Review questions in ophthalmology

Lens/Cataract

EDWARD Y. KOO

QUESTIONS

QUESTIONS 1–5 Pertain to Figures 11-1 to 11-6.

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FIGURE 11-1

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FIGURE 11-2

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FIGURE 11-3 From Tasman W, Jaeger E. The Wills Eye Hospital Atlas of Clinical Ophthalmology. Second Edition. Lippincott Williams & Wilkins, 2001.

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FIGURE 11-4

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FIGURE 11-5

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FIGURE 11-6

1   Which cataract is associated with the long-term use of amiodarone?

     A)   Figure 11-1

     B)   Figure 11-2

     C)   Figure 11-3

     D)   Figure 11-4

2   Which can be found in a patient with deafness and hemorrhagic nephritis?

     A)   Figure 11-5

     B)   Figure 11-2

     C)   Figure 11-4

     D)   Figure 11-3

3   A patient has the cataract pictured in Figure 11-2. Which is a true statement about this patient?

     A)   A Vossius ring can be found on the anterior lens capsule.

     B)   The patient may have elevated intraocular pressure (IOP).

     C)   Patients may also have involvement of their liver and brain.

     D)   The cataract is usually visually significant.

4   What additional finding would not be seen in the patient with the cataract displayed in Figure 11-6?

     A)   Temporal bossing

     B)   Muscle weakness

     C)   Angle-closure glaucoma

     D)   Mental retardation

5   Which cataract might be found during a newborn’s examination?

     A)   Figure 11-4

     B)   Figure 11-2

     C)   Figure 11-3

     D)   Figure 11-6

6   The lens finding shown in Figure 11-5 is due to:

     A)   traumatic injury

     B)   systemic metabolic disease

     C)   radiation damage

     D)   advanced mature lens changes

7   Which of the following types of cataracts is classically associated with myotonic dystrophy?

     A)   Nuclear cataract

     B)   Polychromatic crystalline cataract

     C)   Posterior subcapsular cataract

     D)   Anterior polar cataract

8   A 5-year-old Caucasian boy presents with difficulty seeing the blackboard at school. Upon examination, he is found to be highly myopic. He is short of ­stature and has short stubby fingers with broad hands and tight joints. Which of the ­following is most likely?­

     A)   Prone to angle-closure glaucoma aggravated by the administration of pilocarpine

     B)   Prone to angle-closure glaucoma aggravated by the administration of a cycloplegic

     C)   Normal-appearing parents

     D)   Higher risk of lens dislocation with minor trauma

9   Which of the following test acuity by means of contrast sensitivity?

     A)   Pelli–Robson chart

     B)   Purkinje vascular phenomenon

     C)   PAM (potential acuity meter)

     D)   Blue-field entoptic test

10  When did the cataract in Figure 11-7 develop?

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FIGURE 11-7

     A)   Between birth and 2 years of age

     B)   During adolescence

     C)   In utero

     D)   Over age 40

11  Which of the following is incorrect concerning drug-induced cataracts?

     A)   Amiodarone causes stellate anterior axial pigment deposition.

     B)   Psoralen plus ultraviolet A (PUVA) treatment can cause cataracts.

     C)   Prolonged treatment of eyelid dermatitis with topical steroids can cause cataracts.

     D)   Echothiophate use in adults causes progressive cataract formation.

QUESTIONS 12 and 13 A 72-year-old man who underwent uncomplicated cataract extraction with a posterior chamber intraocular lens (PCIOL) implant 2 months ago presents with painless, decreased vision in the operated eye. The patient has a history of well-controlled type II diabetes and primary open-angle glaucoma (POAG) controlled on travoprost 0.004% OU q.i.d.

The patient’s best-corrected visual acuity (BCVA) is 20/40, whereas at the 1-month postoperative visit it was 20/20.

The anterior-segment examination is unremarkable with a deep and quiet anterior chamber and a well-healed temporal clear-corneal incision. The PCIOL is well centered in the capsular bag. Dilated fundus exam reveals an optic nerve with a cup-to-disc ratio of 0.5, a few peripheral microaneurysms, and a blunted foveal light reflex. The rest of the fundus exam is unremarkable.

12  The most useful diagnostic step to take next would be to:

     A)   perform a spectral domain macular optical coherence tomography (OCT)

     B)   perform gonioscopy

     C)   perform fluorescein angiography

     D)   perform ultrasound biomicroscopy

13  Which of the following would be the best course of action for treating this patient?

     A)   Start patient on topical NSAID, steroid, and oral acetazolamide.

     B)   Start patient on topical NSAID and steriod.

     C)   Start patient on topical NSAID, steroid, and discontinue travoprost.

     D)   Treat patient with anti-VEGF medication.

14  Which of the following would least likely be associated with the eyes shown in ­Figure 11-8?

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FIGURE 11-8

     A)   Long, spider-like fingers

     B)   Non–progressive lens subluxation

     C)   Low risk of retinal detachment

     D)   Abnormality in fibrillin

15  Which of the following would be the most appropriate initial management in the patient in Figure 11-8?

     A)   Immediate surgical removal of the lens

     B)   Spectacle or contact lens correction of the refractive error

     C)   No treatment because there is only a low risk of amblyopia

     D)   Pilocarpine to constrict the pupil

QUESTIONS 16 and 17

16  An infant presents with the appearance shown in Figure 11-9. The following are all characteristics of the condition shown except:

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FIGURE 11-9 From Tasman W, Jaeger E. The Wills Eye Hospital Atlas of Clinical Ophthalmology. Second Edition. Lippincott Williams & Wilkins, 2001.

     A)   prone to angle-closure glaucoma

     B)   progressive cataract formation

     C)   unilateral process

     D)   autosomal dominant inheritance

17  Differential diagnosis of the patient in Figure 11-9 includes all of the following except:

     A)   retinoblastoma

     B)   retinopathy of prematurity

     C)   homocystinuria

     D)   Coats disease

18  A 6-month-old infant presents with a unilateral, complete cataract OD. There is no family history of eye disease. Which would be most helpful in determining the etiology?

     A)   TORCH (toxoplasmosis, other agents, rubella, cytomegalovirus, herpes simplex) titers and syphilis serology

     B)   B-scan ultrasonography

     C)   Chromosomal analysis

     D)   Urine protein and reducing substances

19  Regarding age-related cataracts, which is correct concerning the following histopathologic changes?

     A)   Posterior subcapsular cataract—morgagnian globules

     B)   Cortical cataracts—Wedl (bladder) cells

     C)   Nuclear sclerotic cataracts—homogenous, loss of cellular laminations

     D)   Elschnig pearls—proliferation of lens capsule

QUESTIONS 20 and 21

20  A 15-year-old boy presents with bilateral, symmetric findings. His left eye is pictured in Figure 11-10. He is tall with blond hair. Both of his parents appear normal. Which of the following is least likely to be found in this patient?

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FIGURE 11-10

     A)   Mental retardation

     B)   Osteoporosis

     C)   Decreased serum levels of methionine

     D)   Increased thromboembolism with surgery and general anesthesia

21  Which would be appropriate therapy for this patient (Fig. 11-10)?

     A)   Vitamin A

     B)   Coenzyme Q

     C)   Vitamin B6

     D)   Low phenylalanine diet

22  Which of the following concerning polar cataracts is correct?

     A)   Anterior polar cataracts usually cause more visual disturbance than posterior polar cataracts.

     B)   Posterior polar cataracts have been associated with remnants of the tunica vasculosa lentis.

     C)   Both anterior and posterior polar cataracts can be sporadic or recessively inherited.

     D)   Posterior polar cataracts invariably progress to complete cataracts.

QUESTIONS 23 and 24

23  Complications during or after cataract surgery in the patient shown in Figure 11-11 will most likely be due to:

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FIGURE 11-11

     A)   severe postoperative inflammation

     B)   zonular dehiscence

     C)   corneal decompensation

     D)   retention of viscoelastic

24  In which of the following individuals is this most typically found?

     A)   Young, myopic males

     B)   Men with type-A personality

     C)   Women with tall, thin stature

     D)   Elderly, Caucasian women

25  A dispersive ophthalmic viscosurgical device (OVD) used in phacoemulsification has which of the following properties?

     A)   Adheres to and protects endothelium from damage

     B)   Easy to remove at the end of case

     C)   Retained viscoelastic does not cause an increase in IOP postoperatively

     D)   Prevents collapse of the anterior chamber during high vacuum

26  During a complicated cataract removal case, the lens and capsular bag were both removed and an anterior chamber lens was placed. The first day postoperatively, the IOP is 50 mm Hg and the iris is bowed forward around the intraocular lens (IOL). Which of the following measures would be most effective?

     A)   Topical glaucoma medications and close observation

     B)   Laser peripheral iridectomy

     C)   Increased frequency of the topical steroid

     D)   Paracentesis to release aqueous fluid

27  A patient has with-the-rule astigmatism. During uncomplicated cataract surgery, a one-piece toric PCIOL is placed into the capsular bag and aligned with the astigmatism. The day following surgery, the lens appears to have rotated 90°. Which of the following statements is most accurate?

     A)   Lens explantation is necessary because the lens is not stable.

     B)   The measured astigmatism has increased.

     C)   The lens should have been placed in the ciliary sulcus.

     D)   Rotation of the lens can be done anytime after the first 3 months.

QUESTIONS 28 and 29 A 1-week-old baby is noted by the pediatrician to have an abnormal red reflex of both eyes. His right eye is shown in Figure 11-12. The left eye has a similar appearance. Both eyes are otherwise normal.

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FIGURE 11-12

28  Which of the following may be the most appropriate therapy for this infant?

     A)   Patch the eye that best fixes and follows and perform surgery on the other eye.

     B)   Perform surgery on one eye as soon as possible and the other eye after 3 months of age.

     C)   Perform surgery on one eye with immediate aphakic correction; perform surgery on the other eye before 3 months of age.

     D)   Observe until 3 months of age and perform cataract surgery only if nystagmus develops.

29  Appropriate surgical methods or steps during cataract surgery on this infant include all of the following except:

     A)   aspiration of the cataractous lens

     B)   implantation of posterior chamber IOL

     C)   posterior capsulectomy and limited anterior vitrectomy

     D)   extracapsular cataract extraction

30  What is the cause for posterior capsular opacification following phacoemulsification and implantation of an IOL?

     A)   Fibrovascular ingrowth stimulated by the lens

     B)   Bacterial sequestration and colonization

     C)   Proliferation of residual lens epithelium

     D)   Toxicity of the IOL

31  Which of the following is the least common expected complication following ­neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy?

     A)   Iritis

     B)   Cystoid macular edema (CME)

     C)   Corneal edema

     D)   Elevated IOP

32  Which of the following is true concerning the different designs of phacoemulsification machines?

     A)   The peristaltic pump requires a slow building of vacuum for aspiration.

     B)   The diaphragm pump allows instantaneous vacuum.

     C)   The Venturi pump has stepwise increases in vacuum.

     D)   The speed of rollers in the peristaltic pump allows linear control of vacuum.

33  Excessive iris prolapse during extracapsular cataract extraction via phacoemulsification may be caused by all of the following except:

     A)   infusion bottle height too high

     B)   wound size too large for phacoemulsification tip

     C)   excessive phacoemulsification power

     D)   suprachoroidal hemorrhage

QUESTIONS 34 and 35 A 37-year-old woman is hit in the left eye with a metallic foreign body. On examination, you observe a corneal laceration, rupture of the lens capsule with lens opacification and subluxation, and vitreous present anterior to the lens. No foreign body is found and the posterior pole appears normal.

34  Following repair of the corneal laceration, which of the following is the best approach?

     A)   Pars plana vitrectomy, lensectomy

     B)   Extracapsular cataract extraction via nucleus expression, anterior vitrectomy

     C)   Extracapsular cataract extraction via phacoemulsification, anterior vitrectomy

     D)   Intracapsular cataract extraction, anterior vitrectomy

35  Following lens removal and vitrectomy, you notice an iridodialysis that extends from the 5 o’clock position to the 7 o’clock position. Which of the following is the most correct statement regarding secondary lens implantation in this patient?

     A)   A posterior chamber lens would likely have adequate support.

     B)   A sutured posterior chamber lens is appropriate.

     C)   Anterior chamber lens implantation would be technically easiest and most stable.

     D)   The patient is best left aphakic and should wear an aphakic contact lens.

QUESTIONS 36 and 37 A 65-year-old ex-CEO of a Fortune 500 company underwent sequential uncomplicated cataract surgery in both eyes 1 month ago with implantation of diffractive multifocal IOLs (MFIOLs) OU. His uncorrected VA is 20/20 OU. But he complains of increased glare and halos at night with a “Vaseline-like” vision that fluctuates during the day. On examination, he is noted to have 1+ meibomian gland insipation, an increased tear breakup time, and a clear cornea with a well-healed temporal incision OU. The MFIOLs are both well centered in the round pupil. Retinal exam is unremarkable.

36  The least useful next step would be:

     A)   obtain a corneal wave front analysis

     B)   perform lissamine green or rose bengal testing

     C)   perform manifest refraction

     D)   measure scotopic pupil size

37  All these actions would be considered reasonable in the management of a dissatisfied patient who had a refractive multifocal IOL implanted except:

     A)   trial of brimonidine or diluted pilocarpine drops

     B)   treatment with warm compresses and lid scrubs

     C)   perform customized wave front–guided PRK or LASIK

     D)   implant a piggyback IOL

38  Which of the following is correct concerning cataract surgery in patients with nanophthalmos?

     A)   The chances for a poor visual outcome are similar to those in other cataract surgeries.

     B)   Extracapsular cataract extraction without IOL insertion is the recommended procedure.

     C)   Trabeculectomy is not recommended at the time of cataract extraction.

     D)   Anterior sclerotomies may be indicated at the time of surgery.

39  A 76-year-old man is scheduled for cataract surgery in his right eye as his visual acuity has decreased to 20/200 due to cataract. He previously underwent cataract surgery in the opposite eye, which resulted in an expulsive choroidal hemorrhage and no light perception vision. All of the following may be steps to prevent an ­expulsive hemorrhage in this eye except:

     A)   placement of patient in Trendelenburg postion

     B)   use of a Honan balloon after peribulbar anesthesia

     C)   closure of the wound with nylon sutures

     D)   careful control of blood pressure during surgery

40  Which of the following is correct regarding cataract surgery in patients with uveitis?

     A)   Placement of the IOL should be in the posterior chamber in patients with juvenile rheumatoid arthritis and iridocyclitis.

     B)   Ideally, uveitis should be quiet for 3 to 6 months before elective surgery.

     C)   Patients with Fuchs heterochromic iridocyclitis have a poor prognosis.

     D)   The risk of complications is increased in patients with pars planitis.

41  The risk of complications during cataract extraction in an eye that has previously undergone pars plana vitrectomy is primarily due to:

     A)   collapse of the globe during surgery

     B)   positive pressure from the vitreous cavity

     C)   the excessive mobility of the posterior capsule

     D)   iridodonesis

42  A patient is sent to you for decreased visual acuity due to cataracts. On examination, you find significant nuclear sclerotic cataracts and a visual acuity of 20/80 in each eye. Dilated fundus examination shows proliferative diabetic retinopathy and clinically significant macular edema. Regarding cataract surgery, you should tell the patient that:

     A)   cataract surgery should be performed as soon as possible to better visualize the fundus.

     B)   an attempt should be made to perform photocoagulation before cataract surgery.

     C)   extracapsular cataract extraction without IOL implantation is the procedure of choice.

     D)   extracapsular cataract extraction with intact posterior capsule is associated with a greater chance of neovascular glaucoma postoperatively.

43  A 72-year-old woman presents complaining of pain and redness in her left eye (Fig. 11-13). Moderate anterior chamber cell and flare are present as is minimal corneal edema. IOP is 38 mm Hg, and the angle appears open, although the view is poor. She has had very poor vision in this eye for at least 6 months. No relative afferent papillary defect is noted. All of the following are acceptable management options at this time except:

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FIGURE 11-13

     A)   IOP-lowering agents and topical steroids

     B)   laser peripheral iridotomy and topical steroids

     C)   extracapsular cataract extraction with posterior chamber IOL insertion

     D)   intracapsular cataract extraction if significant zonular dehiscence is present

44  A 60-year-old man successfully undergoes phacoemulsification of the nuclear sclerotic cataract in his right eye. The surgeon accidentally leaves a moderate amount of viscoelastic in his eye. How long after completion of the case might the patient experience a significant spike in IOP?

     A)   30 minutes

     B)   4 hours

     C)   10 hours

     D)   24 hours

QUESTIONS 45 and 46 A 65-year-old man underwent cataract surgery with placement of a posterior chamber IOL. He presents 2 years later as shown in Figure 11-14. He has l­ow-grade inflammation and 1+ anterior chamber cellular reaction.

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FIGURE 11-14

45  The cause for this condition is often attributed to:

     A)   infection with P. acnes

     B)   use of silicone IOLs

     C)   retained cortical material

     D)   a small capsulorrhexis

46  Treatment for this might be:

     A)   topical steroids

     B)   intraocular vancomycin

     C)   IOL exchange

     D)   use of the YAG laser to disrupt the whitish material

47  A patient with the preoperative refraction OD of −3.00 + 2.00 × 90 has a visually significant cataract in this eye. Keratometry is 40.00 at 180 and 42.00 at 90. Which length and location of the cataract scleral tunnel might help decrease the amount of late postoperative astigmatism for the patient?

     A)   3.5-mm scleral incision superiorly

     B)   6.0-mm scleral incision superiorly

     C)   3.5-mm scleral incision temporally

     D)   6.0-mm scleral incision temporally

48  After removal of the anterior chamber IOL, you decide to place a scleral-sutured posterior chamber IOL. The needle should be passed approximately how far posterior to the limbus?

     A)   2.0 mm

     B)   1.5 mm

     C)   0.75 mm

     D)   0.25 mm

49  A 68-year-old man underwent cataract extraction with phacoemulsification and insertion of a posterior chamber IOL. The first day postoperatively, he comes back with moderate epithelial and stromal edema. One week later, the edema is still present. Which is not a cause for his persistent corneal edema?

     A)   Elevated IOP

     B)   Chemical toxicity

     C)   Epithelial downgrowth

     D)   Surgical trauma

50  A 70-year-old man underwent extracapsular cataract 2 years ago that was complicated by mild wound dehiscence. This was observed, and he recovered good vision over the past month. His current IOP is 5 mm Hg in that eye. Slit-lamp examination reveals the finding shown in Figure 11-15. This most likely represents:

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FIGURE 11-15

     A)   localized bullous keratopathy

     B)   limbal HSV infection

     C)   conjunctival hyperplasia

     D)   filtering bleb

ANSWERS

1   D) Figure 11-4

2   D) Figure 11-3

3   C) Patients may also have involvement of their liver and brain.

4   C) Angle-closure glaucoma

5   C) Figure 11-3

6   D) Advanced mature lens changes

     The following figure numbers enumerate the pictured cataracts:

     Figure 11-1 = posterior subcapsular cataract

     Figure 11-2 = sunflower cataract, Wilson disease

     Figure 11-3 = anterior polar cataract

     Figure 11-4 = phenothiazine cataract

     Figure 11-5 = morgagnian cataract

     Figure 11-6 = Christmas tree cataract, myotonic dystrophy

     The posterior subcapsular cataract can be found in many patients as a result of age-related changes; however, corticosteroid use has also been implicated in causing this opacity.

     Wilson disease is a multisystem disease as a result of abnormal copper metabolism. Copper accumulates in the anterior lens capsule producing the sunflower appearance. Copper deposition in Descemet membrane produces the brownish Kayser–Fleischer ring as well. Systemic manifestations include cirrhosis, renal impairment, and degeneration of the basal ganglia. Treatment is directed toward lowering copper levels with penicillamine. The cataract is usually not visually significant.

     Anterior polar cataractsare idiopathic (90%) remnants of the hyaloid system. These are typically present from birth, nonprogressive, and do not affect vision. They have been reported in association with anterior lenticonus as part of Alport syndrome which is inherited in an X-linked dominant pattern, due to mutations in the COL4A5 gene (deafness, glomerulonephritis).

     Phenothiazine and amiodarone can form deposits in the anterior lens capsule as shown in the cataract in Figure 11-5. These do not affect vision.

     Morgagnian cataracts are mature cataracts in which the peripheral cortical material becomes liquefied and the dense central nucleus can sink inferiorly.

     The multiple polychromatic crystalline cataract, or “Christmas tree” cataract, is associated with myotonic dystrophy. These are not present at birth, but develop as the patient ages. Patients do not typically have symptoms from these crystals. Associated systemic findings with myotonic dystrophy include temporal bossing, muscular atrophy and weakness, mental retardation, and abnormalities in cardiac conduction.

7   B) Polychromatic crystalline cataract

     Cataracts occur in almost all adults with myotonic dystrophy. Iridescent crystals, usually red or green in color in the anterior and posterior subcapsular regions, make up the classic early lens changes.

8   A) Prone to angle-closure glaucoma aggravated by the administration of pilocarpine

     The patient has a classic description of Weill–Marchesani syndrome, an autosomal recessively inherited disorder. Given the spherical shape of the lens, patients are prone to angle-closure glaucoma, which is aggravated by miosis. Cycloplegia may decrease pupillary block by tightening zonules, decreasing anteroposterior lens diameter, and pulling the lens posteriorly.

9   A) Pelli–Robson chart

     The Pelli–Robson chart, Regan contrast sensitivity charts, and Vectorvision are contrast sensitivity tests. The PAM uses the principle of the indirect ophthalmoscope to project an image of a letter chart on the macula of the patient. The Purkinje vascular phenomenon and the blue-field entopic test are visualizations of the vasculature of the eye itself when light is projected through the eyelids or sclera. These tests are highly subjective and variable.

10  C) In utero

     Pictured in Figure 11-7 is a sutural cataract demonstrating opacification of the fetal Y sutures. This is a congenital cataract with the formation occurring during development of the fetal lens nucleus.

11  B) Psoralen plus ultraviolet A (PUVA) treatment can cause cataracts.

     A 25-year prospective study done in Boston by RS Stern showed that proper use of PUVA treatment does not increase cataract risk but does increase the risk of squamous cell carcinoma. Amiodarone and phenothiazine cause stellate cataracts in the anterior lens capsule. All forms of steroids have been associated with cataract formation. Echothiophate has been associated with progressive cataract formation in adults.

12  B) Perform gonioscopy

     Although the incidence of CME has decreased significantly due to the less-­traumatic surgical techniques now used for cataract extraction, it still remains a significant cause of decreased postoperative visual acuity. The incidence of clinical CME is now estimated to be 1% to 2% following uncomplicated cataract extraction. The incidence of angiographic evidence of CME is 10 times greater at around 10% to 20%. A detailed history followed by a careful slit-lamp examination should be done of both the anterior and posterior segments. A gonioscopy is important to check for retained lens fragments and to determine the position of the haptics and should be done prior to ordering any imaging studies. OCT is useful in identifying fluid at the intraretinal and subretinal levels as well as evaluating the vitreomacular interface area. In addition, OCT is useful in following the amount of retinal thickening, thus allowing assessment of the therapeutic response. Fluorescein angiography will demonstrate the classic petaloid leakage in the fovea as well as disc hyperfluorescence. Ultrasound biomicroscopy can be considered in cases where a retained lens fragment or malpositioned IOL implant is suspected but not directly visualized by slit-lamp examination or gonioscopy.

13  C) Start patient on topical NSAID, steroid, and discontinue travoprost.

     Corticosteroids and NSAIDs are the mainstay of treatment for routine postoperative CME. Corticosterioids inhibit the enzyme phospholipase A2, directly preventing the production of arachidonic acid and indirectly decreasing the production of prostaglandins and leukotrienes. NSAIDs inhibit the enzyme cyclooxygenase, directly preventing the production of prostaglandins and leukotrienes. Several recent studies have shown a potential association between prostaglandin use and the incidence of CME after cataract surgery in glaucoma patients. Although many surgeons do not stop prostaglandins prior to routine cataract surgery, in this patient due to his preexisting diabetes as well as the development of postoperative CME, it would be most prudent to stop his travoprost and prescribe a non–­prostaglandin glaucoma medication while he is being treated for his CME. Oral acetazolamide has been used to treat macular edema caused by inflammation. Although it can be effective, its use is limited by undesirable systemic side effects and allergic reactions in sulfa-allergic patients. Anti-VEGF medication may be considered in patients who are refractory to more conventional treatments.

14  C) Low risk of retinal detachment

     Marfan syndrome is a genetic abnormality in fibrillin, a structural protein in collagen. Patients with Marfan’s are tall; have long, thin fingers; have hyperextensible joints; and have aneurysms of the aorta. Ocular manifestations include subluxation of the lenses superotemporally and a high risk of retinal detachment.

15  B) Spectacle or contact lens correction of the refractive error

     Given the high risk of retinal detachment, the increased risk of complications with routine cataract surgery, and the generally nonprogressive nature of the subluxation, spectacles or contact lenses should be tried first. Most cases are amenable to spectacles or contact lenses. Pupil dilation is sometimes helpful, because it allows the patient to see around the subluxed lens. A reading add is needed secondary to poor accommodation of the lens due to zonular dehiscence.

16  D) Autosomal dominant inheritance

     Persistent hyperplastic primary vitreous (PHPV) is a congenital, nonhereditary ocular malformation. Associated findings include elongation of ciliary processes, prominent radial iris vessels, persistent hyaloid artery, microphthalmia, and ectopia lentis.

17  C) Homocystinuria

     Homocystinuria does not cause leukocoria but is associated with ectopia lentis. There are no characteristic signs or symptoms in newborns. Early detection relies on newborn blood and urine screening.

18  B) B-scan ultrasonography

     With no family history and unilateral complete cataracts, screening labs are not warranted. Urine protein and reducing substance analysis are screens for Lowe syndrome or galactosemia with bilateral cataracts. Bilateral cataracts are associated with chromosomal abnormalities such as trisomy 13 and Turner syndrome. If no view to the fundus is possible, then B-scan ultrasonography of the eye is necessary to rule out secondary causes such as intraocular tumors which produce unilateral cataracts.

19  C) Nuclear sclerotic cataracts—homogenous, loss of cellular laminations

     In posterior subcapsular cataracts, there is posterior migration of lens epithelial cells, which swell along the posterior capsule. These swollen epithelial cells are called Wedl or bladder cells. In cortical cataracts, there is hydropic swelling of the lens fibers with globules of eosinophilic material in the spaces between the lens fibers called morgagnian globules. Elschnig pearls are formed by the accumulation of proliferating remnant lens epithelial cells.

20  C) Decreased serum levels of methionine

     The history and physical findings are consistent with a diagnosis of homocystinuria, in which serum levels of homocystine and methionine are elevated. Inheritance is autosomal recessive. Patients are normal at birth but develop seizures, osteoporosis, and mental retardation. Classic lens dislocation is bilateral, symmetric, usually inferonasal. Patients with homocystinuria are also prone to thromboembolic episodes and are at risk of increased thromboembolism with surgery and general anesthesia.

21  C) Vitamin B6

     In homocystinuria, there is a disorder in the metabolism of methionine. Deficient cysteine is thought to weaken zonules, which have a high concentration of cysteine. A low methionine, high cysteine diet with trimethylglycine, folic acid, and pyridoxine (vitamin B6) supplementation has shown promise in treating these patients and in reducing ectopia lentis. Coenzyme Q has been touted for patients with Leber hereditary optic neuropathy, and Vitamin A may be helpful in some cases of retinitis pigmentosa. A low pheylalanine diet is the main treatment for patients with penylketonuria.

22  B) Posterior polar cataracts have been associated with remnants of the tunica vasculosa lentis.

     Anterior polar cataracts are usually small and nonprogressive, do not usually impair vision, and may be seen in association with microphthalmos, a persistent papillary membrane, and anterior lenticonus. Posterior polar cataracts cause more visual impairment and tend to be larger than anterior polar cataracts. Both can be autosomal dominant or sporadic. Posterior polar cataracts may be associated with posterior lenticonus or a remnant of the tunica vasculosa lentis.

23  B) Zonular dehiscence

     This is an example of pseudoexfoliation syndrome. Note the deposition of pseudoexfoliative debris on the anterior lens capsule and at the pupillary margin. This syndrome is associated with an approximately five times higher rate of vitreous loss during extracapsular cataract extraction. In some cases, phacodonesis or iridodonesis may be evident at the slit lamp, signaling lens subluxation. Other times, however, lens subluxation and zonular dehiscence may not be evident until during surgery. Severe postoperative inflammation and corneal decompensation are not necessarily more common in these patients. Retained viscoelastic may cause a temporary rise in IOP after surgery, which may complicate cases with pseudoexfoliative glaucoma.

24  D) Elderly, Caucasian women

     Pseudoexfoliation is typically found in people of Scandinavian descent, and the incidence increases with age. Young, myopic males may be predisposed to pigmentary dispersion syndrome. The central serous choroidopathy patient characteristically is a type-A personality man. Tall, thin body habitus may be found with Marfan syndrome.

25  A) Adheres to and protects endothelium from damage

     Dispersive OVDs are low-molecular-weight, short-chained molecules that are good at coating intraocular surfaces but are not as effective as cohesive OVDs at maintaining surgical space. With high vacuum, the dispersive OVDs tends to fragment, making it more difficult to remove from the eye whereas cohesive OVDs with their high-molecular-weight, long-chained molecules tend to interlock and intertwine, making removal from the eye much easier. A layer of dispersive OVD can protect the endothelium from lens fragments, since it is not as readily removed from the eye during phacoemulsification. All viscoelastics, if retained in the eye, can cause increases in IOP.

26  B) Laser peripheral iridectomy

     This case describes iris bombé, which can occur if the aqueous humor produced by the ciliary body is unable to move around the IOL to the trabecular meshwork. The iris is pushed forward peripherally and causes a secondary angle closure. A similar situation can occur in uveitis if synechiae form 360° around the pupillary border. A peripheral iridectomy is necessary to create an alternate location for the aqueous. A paracentesis would not be easy to perform with the forward position of the iris. Release of the aqueous may worsen the condition as well.

27  B) The measured astigmatism has increased.

     Toric lenses are designed to counteract the corneal astigmatism. When the lens rotates off axis, the amount of astigmatism correction decreases. When it rotates 90° off axis, the astigmatism measured will be greater than the corneal astigmatism. The lens should be rotated back to the correct position within several weeks after surgery before the anterior and posterior capsule fuse together and make it more difficult to manipulate the lens. The lens should not be placed in the ciliary sulcus because a one-piece lens would not be stable in this location.

28  C) Perform surgery on one eye with immediate aphakic correction; perform surgery on the other eye before 3 months of age.

     Bilateral congenital cataracts of significant opacity, as in Figure 11-12, should be addressed surgically as soon as possible. Aphakic correction with an aphakic contact lens is performed immediately postoperatively. Surgery on the second eye should be done as soon as possible after the first eye. Vision may develop normally without surgery if the lens opacity is axial and the pupils are continuously dilated.

     When indicated, surgery is ideally performed before the child is 3 months of age. Profound amblyopia is present by this age and nystagmus develops. Cataract surgery after the development of nystagmus often does not improve visual acuity and nystagmus persists.

29  B) Implantation of posterior chamber IOL

     Cataract surgery in infants differs from that in adults in several important ways. In infants, the nucleus, although opaque, is soft and gummy. Marked opacification and membrane formation occur on the posterior capsule and anterior hyaloid if the posterior capsule is left untouched. Additionally, significant adhesions exist between the lens and anterior hyaloid face. For these reasons, intracapsular cataract extraction is not considered because vitreous loss may occur. Extracapsular cataract extraction is performed by aspirating the nucleus and cortex with a phacoemulsification handpiece or vitrectomy instrument. A posterior capsulectomy is followed by a limited anterior vitrectomy. Postoperative aphakic correction via contact lens can be started immediately. Implantation of IOLs in children is controversial. In infants under 2 years of age, lenses are generally contraindicated because the eye undergoes a drastic change in refractive power as it grows. An implanted IOL would have to be removed or exchanged in later years.

30  C) Proliferation of residual lens epithelium

     Opacification of the posterior capsule following extracapsular cataract extraction is not an uncommon problem. The main causes include proliferation of retained lens epithelium and capsular fibrosis and contraction. An opening in the capsule can be made with a YAG laser, providing a clear visual pathway.

31  C) Corneal edema

     Complications of YAG capsulotomies result from the energy delivered to the eye. The YAG creates microexplosions that disrupt the posterior capsule. This may also put traction on the vitreous, causing a retinal break. Elevated IOP, iritis, and macular edema are also resulting complications. Corneal edema can occur but should not result if the laser is properly focused on the posterior capsule.

32  D) The speed of rollers in the peristaltic pump allows linear control of vacuum.

     Three kinds of aspiration systems exist in phacoemulsification machines. The peristaltic pump has rollers that move along tubing and create a relatively rapid rise in vacuum. The diaphragm pump has valves over both the inlet and outlet of a fluid chamber covered by a diaphragm. This system allows a slower build of vacuum. The Venturi pump produces the most rapid increase in vacuum. This, however, can be the most dangerous because it allows almost instantaneous engagement of unwanted tissues such as capsule or iris.

33  C) Excessive phacoemulsification power

     Iris prolapse associated with an excessively deep anterior chamber suggests too high a bottle height, which can be remedied by simply lowering the bottle. If iris prolapse is associated with a normal or shallow anterior chamber depth, this may be caused by wound leak around the phacoemulsification tip or possibly suprachoroidal hemorrhage. If leak around the phaco tip is evident, a temporary suture may be placed. Peripheral iridectomy at the site of prolapse may also help reposit the iris. Excessive phacoemulsification power does not result in iris prolapse.

34  A) Pars planavitrectomy, lensectomy

     When traumatic capsular rupture is present with lens subluxation and disruption of the anterior hyaloid face, the pars plana approach for lensectomy and vitrectomy is the most appropriate. The presence of a hard nucleus, if present, may make this technically difficult. Extracapsular cataract extraction would not be indicated with loss of zonular integrity and presence of free vitreous. Intracapsular cataract extraction is contraindicated when vitreous is present and the capsule is ruptured.

35  B) A sutured posterior chamber lens is appropriate.

     In this case, support for a posterior chamber lens, either in the sulcus or capsular bag, would very likely be inadequate. Anterior chamber lens placement should be considered, but the presence of a large iridodialysis may complicate placement. Other factors that are relative contraindications for anterior chamber lens placement, if present, include corneal endothelial dystrophy, abnormal angle vessels or structures, and peripheral anterior synechiae. Placement of an anterior chamber lens would, however, be technically easiest. Sulcus fixation via transscleral polypropylene (Prolene) sutures would be appropriate but is technically more difficult. Aphakic contact lens wear is an option but not the best one.

36  A) Obtain a corneal wave front analysis

     With the increasing popularity of MFIOLs, it is incumbant on the surgeon to set proper expectations and to correctly identify which patients are reasonable candidates for MFIOLs prior to surgery.A systematic approach to considering the multiple possible abnormalities that can cause visual symptoms is required. This patient has excellent uncorrected visual acuity (VA) with well-centered MFIOLs yet still complains of blurry vision with halos and glare. The evaluation of his scotopic pupil size may be helpful as edge glare from the optic in patients with large pupils may be improved by a trial of brimonidine or dilute pilocarpine drops. Vital staining with lissamine green or rose bengal may elucidate the effects of dry eye syndrome and lid margin disease, which are common causes of poor vision in MFIOL patients. Mild residual refractive error can cause glare, blurry vision and ghosting of images and can be diagnosed with a careful refraction. Wave front analysis can help quantify and delineate the amount of higher-order aberrations caused by irregular corneal healing and MFIOLs themselves, but this is less common and would not be the initial step one would perform in evaluating a dissatisfied MFIOL patient.

37  C) Perform customized wave front–guided PRK or LASIK

     A trial of brimonidine or diluted pilocarpine drops to reduce or prevent mydriasis under mesopic or scotopic conditions may reduce the symptoms of glare and halos. Treatment of lid margin disease with warm compresses and lid scrubs may help stabilize the tear film, thus improving vision clarity. Mild residual refractive errors can be managed with glasses or contact lenses, but significant residual refractive errors are best managed more definitively with PRK, LASIK, IOL exchange, or piggyback IOLs. It is important to wait until the refraction is stabilized, which may take up to 3 to 6 months. A custom wave front–guided ablation is not recommended after refractive MFIOL implantation, since it eliminates negative spherical aberration induced by the refractive MFIOL, thus negating the multifocal effect. A conventional laser ablation is preferred to preserve multifocality.

38  D) Anterior sclerotomies may be indicated at the time of surgery.

     The indications for cataract surgery in nanophthalmic patients are similar to those in other patients. However, the chances for complications and a poor visual outcome are significantly higher. These complications include retinal detachment, choroidal effusion, postoperative angle-closure glaucoma, flat anterior chamber, CME, corneal decompensation, and malignant glaucoma. Extracapsular cataract extraction with posterior chamber lens insertion is generally the procedure of choice, using the smallest incision possible. Some cases with refractory positive vitreous pressure and anterior-segment crowding may do best without IOL implantation. In eyes with significant glaucoma, small incision cataract surgery may be combined with trabeculectomy. When the anterior chamber is shallow preoperatively and the choroid is thickened, anterior sclerotomies are indicated at the time of surgery.

39  A) Placement of patient in Trendelenburg postion

     Risk factors for expulsive choroidal hemorrhage include myopia, glaucoma, atherosclerotic vascular disease, hypertension, and previous expulsive hemorrhage in the opposite eye. Using as small an incision as possible along with being ready to perform a sclerotomy is important. Decompression before opening the globe with digital pressure or another device such as a Honan balloon may be helpful. The wound should be closed with nonabsorbable, preferably nylon sutures to prevent delayed hemorrhage. It is also beneficial to keep blood pressure controlled and the level of anesthesia deep (if general anesthesia is used) during surgery. Shelved or self-sealing incisions allow more rapid closure and repressurization of the globe should bleeding occur. Placing the patient in Trendelenburg position would increase pressure around the eye, thus increasing the chance of having an expulsive hemorrhage.

40  B) Ideally, uveitis should be quiet for 3 to 6 months before elective surgery.

     The indications for cataract surgery in patients with uveitis are similar to those in patients without uveitis. However, complications in the early or late postoperative period may arise in certain uveitides. Elective cataract surgery is best performed after inflammation is quiet for several months. Even minimal or baseline inflammation preoperatively may result in marked inflammation postoperatively. Prophylaxis or treatment may require hourly topical steroids or even systemic steroids.

     IOL implantation is contraindicated in patients with juvenile rheumatoid arthritis–associated iridocyclitis. Development of cyclitic membranes and subsequent ciliary body detachment following extracapsular cataract extraction suggest the need for complete capsular removal. Therefore, combined lensectomy and subtotal vitrectomy either through the limbus or through pars plana is recommended. Patients with Fuchs heterochromic iridocyclitis are among the group that does best following cataract extraction and after IOLs have been safely implanted. A transient postoperative hyphema may develop but resolves without sequelae. Although those with pars planitis do not apparently have a significantly increased risk of complications associated with routine cataract surgery, pars plana lensectomy vitrectomy may be indicated as postoperative vitreous opacities may limit visual acuity. Visual acuity may also be limited by CME.

41  C) The excessive mobility of the posterior capsule

     The posterior capsule is capable of moving more posterior than normal without support of the vitreous. Zonular dehiscence may result from attempted manual expression of the nucleus during extracapsular cataract extraction. The posterior capsule is also more likely to move forward with the lens during phacoemulsification and aspiration in extracapsular cataract extraction via phacoemulsification. As a result, capsular tears may be more likely. Collapse of the globe is usually not problematic with a well-formed phaco incision. Positive pressure from the posterior segment occurs more frequently when the vitreous cavity is occupied by the vitreous.

42  B) An attempt should be made to perform photocoagulation before cataract surgery.

     According to the Early Treatment of Diabetic Retinopathy Study (ETDRS), in diabetic retinopathy, argon laser photocoagulation should be attempted to the degree allowed by the lens opacity before cataract surgery. In this case, concomitant focal and panretinal photocoagulation or focal laser followed by panretinal photocoagulation should be performed. As many laser spots as possible to control neovascularization should be placed before surgery.

     Although extracapsular cataract extraction with or without IOL implantation may be indicated following photocoagulation, maintenance of an intact posterior capsule appears to be important. The intact posterior capsule (or anterior hyaloid face) appears to act as a barrier, to some extent, to the proposed angiogenic factors that lead to development of neovascularization. Successful extracapsular cataract extraction with intact posterior capsule does not appear to increase the risk of anterior-segment neovascularization, leading to postoperative neovascular glaucoma.

43  B) Laser peripheral iridotomy and topical steroids

     This is a case of phacolytic glaucoma due to a hypermature cataract. A dense, white cataract along with anterior-segment inflammation is noted. Lens proteins, which have liquefied, leak through an intact lens capsule and attract macrophages with resultant inflammation. The combination of lens proteins and macrophages then block the trabecular meshwork with elevation of the IOP.

     Definitive treatment is cataract extraction. When possible, however, it may be beneficial to attempt control of inflammation and IOP medically before surgery. Most surgeons will perform extracapsular cataract extraction with IOL implantation, but intracapsular cataract extraction may be preferred if significant zonular dehiscence is discovered. Laser peripheral iridotomy is not indicated as glaucoma in this case is not due to angle closure.

44  B) 4 hours

     Lane and colleagues evaluated IOP elevation associated with three commonly used OVDs (sodium hyaluronate, chondroitin sulfate, and hydroxymethylcellulose), and all produced significant pressure elevations at 4 ± 1 hours postoperatively. Removing the viscoelastic did not eliminate significant postoperative IOP elevation, although when chondroitin sulfate was removed, the pressure elevation was slightly less. Patients who have retained OVDs should be started on Diamox and/or IOP lowering eye drops immediately after surgery.

45  A) Infection with P. acnes

46  B) Intraocular vancomycin

     Chronic postoperative endophthalmitis, as shown here, can occur months to years following cataract surgery. A number of bacterial organisms have been isolated from the whitish plaque, among them P. acnes. The low-grade inflammation can wax and wane and responds to topical steroids. Treatment includes intracameral vancomycin and/or vitrectomy and excision of the plaque.

     Retained cortical material can incite inflammation in the months following cataract surgery, but remote inflammation due to the cortical lens material is unusual. Proliferation of lens epithelium (Elschnig pearls and Soemmering ring) is noninflammatory.

47  B) 6.0-mm scleral incision superiorly

     The patient has with-the-rule astigmatism that has no obvious lenticular component. A 6.0-mm scleral incision placed superiorly may help decrease the patient’s preoperative astigmatism 1.5 ± 0.5 D. A 3.5-mm incision would be more astigmatically neutral with 0.5 ± 0.3 D drift against the rule.

48  C) 0.75 mm

     The ciliary sulcus is approximately 0.85 mm posterior to the limbus in the horizontal meridian and 0.45 mm posterior to the limbus in the vertical meridian (Fig. 11-16). Many transcleral suturing techniques have been described in an effort to overcome the inherent challenge of passing a suture safely through the ciliary sulcus with limited visualization. In general, an oblique needle insertion at the 2 o’clock and 8 o’clock or 10 o’clock and 4 o’clock positions are preferable to decrease the chance of damaging the long ciliary arteries and nerves, which tend to run in the vertical meridian. Figure 11-17 shows an example of a lens designed for transscleral suturing. Note the two eyelets for the sutures.

images

FIGURE 11-16 Tasman W, Jaeger E. The Wills Eye Hospital Atlas of Clinical Ophthalmology. ­Second Edition. Lippincott Williams & Wilkins, 2001.

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FIGURE 11-17 Photograph courtesy of Alcon Laboratories, Inc., Ft. Worth, TX.

49  C) Epithelial downgrowth

     Among the causes of corneal edema the day following cataract extraction are elevated IOP (from inflammation, glaucoma, debris clogging the trabecular meshwork), corneal decompensation (low endothelial counts as in Fuchs dystrophy, endothelial chemical toxicity), or trauma to the endothelium. Epithelial downgrowth would not present immediately after surgery but would take weeks to develop. The corneal decompensation would overlie the area of the downgrowth, and a membrane may be seen on the endothelium and iris.

50  D) Filtering bleb

     This is an inadvertent filtering bleb following cataract surgery.



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