The Massachusetts Eye and Ear Infirmary Illustrated Manual of Ophthalmology, 4th Ed.

8. Lens

Congenital Anomalies

Congenital Cataract

Acquired Cataract

Posterior Capsular Opacification

Aphakia

Pseudophakia

Exfoliation

Pseudoexfoliation Syndrome

Pseudoexfoliation Glaucoma

Lens-Induced Glaucoma

Dislocated Lens

Congenital Anomalies

Definition

Variety of developmental lens abnormalities:

Coloboma

Focal inferior lens flattening due to ciliary body coloboma with absence of zonular support (not a true coloboma); other ocular colobomata (iris) usually exist. Ciliary body tumors may cause a secondary lens “coloboma.”

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FIGURE 8-1 Lens coloboma appears as inferior flattening or truncation of the lens due to lack of zonular attachments when viewed with retroillumination

Lenticonus

Cone-shaped lens due to bulging from a thin lens capsule; either anteriorly or posteriorly, rarely in both directions.

Anterior

Usually males; bilateral; may be associated with Alport’s syndrome (see Congenital Cataract section below).

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FIGURE 8-2 Anterior lenticonus in a patient with Alport’s syndrome. Note peaked slit-beam as it crosses anterior lens surface (arrowhead).

Posterior

More common; slight female predilection; may have associated cortical lens opacities, may be associated with Lowe’s syndrome (see Congenital Cataract section below).

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FIGURE 8-3 Posterior lenticonus with polar cataract.

Lentiglobus

Globe-shaped lens caused by bulging from thin lens capsule; rare.

Microspherophakia

Small spherical lens; may be an isolated anomaly or part of a syndrome (i.e., dominant spherophakia, Weill–Marchesani syndrome, Lowe’s syndrome, Alport’s syndrome, Peter’s anomaly, rubella).

Mittendorf Dot

A small white spot on the posterior lens capsule that represents a remnant of the posterior tunica vasculosa lentis where the former hyaloid artery attached.

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FIGURE 8-4 Mittendorf dot demonstrating a small white spot on the posterior lens capsule that represents a remnant of the posterior tunica vasculosa lentis.

Symptoms

Asymptomatic (Mittendorf dot, coloboma); may have decreased vision (lenticonus, lentiglobus, and microspherophakia), diplopia, or symptoms of angle-closure glaucoma (microspherophakia).

Signs

Normal or decreased visual acuity; may have amblyopia, strabismus, nystagmus, myopia, and an “oil-droplet” fundus reflex on retroillumination in lenticonus and lentiglobus; may have dislocated lens and increased intraocular pressure in microspherophakia.

Differential Diagnosis

See above.

Evaluation

• Complete ophthalmic history and eye exam with attention to cycloplegic refraction, retinoscopy, gonioscopy, lens, and ophthalmoscopy.

Management

• Correct any refractive error.

• Patching or occlusion therapy for amblyopia (see Chapter 12).

• Microspherophakia causing pupillary block is treated with a cycloplegic (scopolamine 0.25% tid or atropine 1% bid); may also require laser iridotomy or lens extraction (see Secondary Angle-Closure Glaucoma section in Chapter 6).

Prognosis

Usually good; poorer if amblyopia exists.

Congenital Cataract

Definition

Congenital opacity of the crystalline lens usually categorized by location or etiology:

Capsular

Opacity of the lens capsule, usually anteriorly.

Lamellar or Zonular

Central, circumscribed opacity surrounding the nucleus; “sand dollar” appearance.

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FIGURE 8-5 Congenital zonular cataract.

Lenticular or Nuclear

Opacity of the lens nucleus.

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FIGURE 8-6 Congenital nuclear cataract with central white discoid appearance.

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FIGURE 8-7 Same patient as Figure 8-6 demonstrating congenital nuclear cataract as viewed with retroillumination.

Polar

Central opacity located near the lens capsule, anteriorly or posteriorly.

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FIGURE 8-8 Congenital posterior polar cataract.

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FIGURE 8-9 Same patient as Figure 8-8 demonstrating congenital polar cataract in retroillumination.

Sutural

Opacity of the Y-shaped sutures in the center of the lens.

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FIGURE 8-10 Congenital cataract with prominent suture lines.

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FIGURE 8-11 Same patient as Figure 8-10 demonstrating congenital sutural cataract in retroillumination.

Etiology

Hereditary or Syndromes

Without chromosomal abnormalities

Autosomal dominant (AD), autosomal recessive (AR), X-linked.

With chromosomal abnormalities

Down’s syndrome (snowflake cataracts), Turner’s syndrome, and others.

Other syndromes

Craniofacial, central nervous system, skin.

Intrauterine Infections

Congenital rubella syndrome

Cataracts, glaucoma, microcornea, microphthalmos, iris hypoplasia, and retinopathy with characteristic fine, granular, salt-and-pepper appearance (most common finding). Other complications include prematurity, mental retardation, neurosensory deafness, congenital heart disease, growth retardation, hepatosplenomegaly, interstitial pneumonitis, and encephalitis.

Congenital varicella syndrome

Cataracts, chorioretinitis, optic nerve atrophy or hypoplasia, nystagmus, and Horner’s syndrome. Systemic findings include hemiparesis, bulbar palsies, dermatomal cicatricial skin lesions, developmental delay, and learning difficulties.

Metabolic

Galactosemia

Bilateral, oil-droplet cataracts from accumulation of galactose metabolites (galactitol) due to hereditary enzymatic deficiency; usually galactose 1-phosphate uridyltransferase, also galactokinase. Associated with mental retardation, hepatosplenomegaly, cirrhosis, malnutrition, and failure to thrive. Mapped to chromosomes 1p (GALE gene), 9p (GALT gene) and 17q (GALK1 gene).

Lowe’s oculocerebrorenal syndrome (X-linked)

Small discoid lens, posterior lenticonus, and glaucoma. Systemic findings include acidosis, aminoaciduria, renal rickets, hypotonia, mental retardation. Female carriers have posterior, white, punctate cortical opacities and subcapsular, plaque-like opacities. Mapped to chromosome Xq25 (OCRL gene).

Alport’s syndrome (AD)

Basement membrane disease associated with acute hemorrhagic nephropathy, deafness, anterior lenticonus, anterior polar or cortical cataracts, and albipunctatus-like spots in the fundus. Mapped to chromosome Xq22 (COL4A5 gene [80% of cases], also COL4A3 and COL4A4 genes).

Other metabolic diseases

Hypoglycemia, hypocalcemia (diffuse lamellar punctate opacities), Fabry’s disease (spoke-like cataracts in 25%), mannosidosis (posterior spoke-like opacities).

Ocular Disorders

Persistent hyperplastic primary vitreous, Peter’s anomaly, Leber’s congenital amaurosis, retinopathy of prematurity, aniridia, posterior lenticonus, tumors.

Other

Birth trauma, idiopathic, and maternal drug ingestion.

Epidemiology

Congenital cataracts occur in approximately 1 of 2000 live births. Roughly one-third are isolated, one-third are familial (usually dominant), and one-third are associated with a syndrome; most unilateral cases are not metabolic or genetic.

Symptoms

Variable decreased vision; may notice white pupil or eye turn.

Signs

Decreased visual acuity, leukocoria, amblyopia; may have strabismus (usually with unilateral cataract), nystagmus (usually does not appear until 2–3 months of age; rarely when cataracts develop after age 6 months), amblyopia; may have other ocular or systemic findings if syndrome exists.

Differential Diagnosis

See Leukocoria in Chapter 7.

Evaluation

• Complete ophthalmic history with attention to family history of eye disease, trauma, maternal illnesses and drug ingestion during pregnancy, systemic diseases in the child, and birth problems.

• Complete eye exam with attention to cycloplegic refraction, retinoscopy, tonometry, gonioscopy, lens (size and density of the opacity as viewed with retroillumination), and ophthalmoscopy.

• May require examination under anesthesia.

• Keratometry and biometry when intraocular lens (IOL) implantation is anticipated.

• Lab tests: TORCH titers (toxoplasmosis, other infections [syphilis], rubella, cytomegalovirus, and herpes simplex), fasting blood sugar (hypoglycemia), urine-reducing substances after milk feeding (galactosemia), calcium (hypocalcemia), and urine amino acids (Lowe’s syndrome).

• B-scan ultrasonography if unable to visualize the fundus (can perform through the lids of a crying child).

• Pediatric consultation.

Management

• Dilation (tropicamide 1% [Mydriacyl] with or without phenylephrine 2.5% [Mydfrin tid) may be used as a temporary measure before surgery to allow light to pass around the cataract; however, surgery should not be delayed.

• If the cataract obscures the visual axis (media opacity > 3 mm) or is causing secondary ocular disease (glaucoma or uveitis), cataract extraction should be performed within days to a week after diagnosis in infants because delay may lead to amblyopia; postoperatively, the child requires proper aphakic correction with contact lens or spectacles if bilateral; depending on age and etiology, consider IOL implantation.

• If the cataract is not causing amblyopia, glaucoma, or uveitis, the child is observed closely for progression.

• Patching or occlusion therapy for amblyopia (see Chapter 12).

• Almost all patients with visually significant, unilateral, congenital cataracts have strabismus and may require muscle surgery after cataract extraction.

• Restrict dietary galactose in galactosemia.

Prognosis

Depends on age and duration of visually significant cataract prior to surgery; poor if amblyopia exists.

Acquired Cataract

Definition

Lenticular opacity usually categorized by location or etiology:

Cortical Degeneration

Caused by swelling and liquefaction of the cortical fiber cells. Various types:

Spokes and vacuoles

Asymmetrically located, radial, linear opacities and punctate dots.

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FIGURE 8-12 Cortical cataract demonstrating white cortical spoking.

Mature cataract

Completely opacified cortex causing the lens to appear white; no red reflex visible from fundus.

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FIGURE 8-13 Mature cataract with white, liquefied cortex.

Morgagnian cataract

Mature cataract with dense nucleus displaced inferiorly in completely liquefied, white cortex.

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FIGURE 8-14 Morgagnian cataract demonstrating a dense, brown nucleus sinking inferiorly in a white, liquefied cortex.

Hypermature cataract

After morgagnian cataract formation, the lens shrinks, the capsule wrinkles, and calcium deposits can form; proteins may leak into the anterior chamber causing phacolytic glaucoma.

Nuclear Sclerosis

Centrally located lens discoloration / opalescence (yellow-green or brown [brunescent]); caused by deterioration of the central lens fiber cells.

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FIGURE 8-15 Cataract with 2+ yellow-green nuclear sclerosis.

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FIGURE 8-16 Brunescent nuclear sclerotic cataract.

Subcapsular Cataract

Anterior subcapsular

Central fibrous plaque caused by metaplasia of the central zone lens epithelial cells beneath the anterior lens capsule. Medications can cause anterior subcapsular stellate changes; acute angle-closure attacks can cause anterior subcapsular opacities (glaukomflecken) due to lens epithelial necrosis.

Posterior subcapsular

Asymmetric granular opacities with a frosted-glass appearance at the posterior surface of the lens; caused by posterior migration of epithelial cells and formation of bladder (Wedl) cells.

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FIGURE 8-17 Posterior subcapsular cataract demonstrating typical white, hazy appearance.

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FIGURE 8-18 Posterior subcapsular cataract due to topical steroid use, as viewed with retroillumination.

Etiology

Senile

Most common; due to age-related lens changes (cortical, nuclear, and /or subcapsular).

Systemic Disease

Many different systemic diseases can cause cataracts, including:

Diabetes mellitus

“Sugar” cataracts are cortical or posterior subcapsular opacities that occur earlier in diabetic patients than in age-matched controls, progress rapidly, and are related to poor glucose control more than duration of disease.

Hypocalcemia

Lens opacities are usually small white dots but can aggregate into larger flakes.

Myotonic dystrophy

Central, polychromatic, iridescent, cortical crystals (Christmas tree cataract); may develop a posterior subcapsular cataract later (see Chronic Progressive External Ophthalmoplegia section in Chapter 2).

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FIGURE 8-19 Polychromatic, refractile, cholesterol deposits within the crystalline lens.

Wilson’s disease

Sunflower cataract due to copper deposition (chalcosis lentis); green-brown surface opacity in the central lens with short stellate processes rather than the full flower petal pattern that occurs in chalcosis (copper foreign body).

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FIGURE 8-20 Sunflower cataract in a patient with Wilson’s disease.

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FIGURE 8-21 Sunflower cataract (chalcosis lentis) with green-brown central opacities in the lens (same patient as Figure 5-90 with Kayser–Fleischer ring).

Others

Fabry’s disease, atopic dermatitis (anterior subcapsular shield-like plaque), NF-2 (posterior subcapsular cataracts), and ectodermal dysplasia.

Other Eye Diseases

Uveitis, angle-closure glaucoma (glaukomflecken), retinal detachment, myopia, intraocular tumors, retinitis pigmentosa (posterior subcapsular cataracts), Refsum’s disease (posterior subcapsular cataracts), Stickler’s syndrome (cortical cataracts), phthisis bulbi.

Toxic

Steroids (posterior subcapsular cataracts), miotic agents, phenothiazines, amiodarone, busulfan; ionizing (X-rays, gamma rays, and neutrons), infrared, ultraviolet, microwave, and shortwave radiation; electricity, and chemicals.

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FIGURE 8-22 Anterior subcapsular star-pattern cataract due to phenothiazine use.

Trauma

Blunt or penetrating; intraocular foreign bodies (iron, copper); and postoperative (i.e., pars plana vitrectomy, trabeculectomy).

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FIGURE 8-23 Dense, white, central cataract due to trauma; also note iridodialysis.

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FIGURE 8-24 Intralenticular foreign body.

Epidemiology

Senile cataracts represent senescent lens changes related, in part, to ultraviolet B radiation. In the Framingham Eye Study, the prevalence of senile cataracts was 42% in adults 52–64 years old, 73% in 65–74-year-olds, and 91% in 75–85-year-olds. African-American men and women were more likely to have cataracts in every age category. Cataracts are the leading cause of blindness worldwide.

Symptoms

Painless, progressive loss of vision, decreased contrast and color sensitivity, glare, starbursts; rarely monocular diplopia.

Signs

Decreased visual acuity (distance vision usually affected more than near vision in nuclear sclerosis, and near vision affected more than distance vision in posterior subcapsular), decreased contrast sensitivity, focal or diffuse lens opacification (yellow, green, brown, or white; often best appreciated with retroillumination), change in refractive error (often a myopic shift); intumescent cataracts may cause the iris to bow forward and lead to secondary angle-closure (see Chapter 6); hypermature cataracts may leak lens proteins and cause phacolytic glaucoma (see Lens-Induced Glaucoma section).

Differential Diagnosis

See above; senile cataract is a diagnosis of exclusion, must rule out secondary causes.

Evaluation

• Complete ophthalmic history with attention to systemic diseases, medications, prior use of steroids, trauma, radiation treatment, other ocular diseases, congenital problems, and functional visual status.

• Complete eye exam with attention to visual acuity, refraction, contrast sensitivity, cornea, gonioscopy, lens, and ophthalmoscopy.

• Consider brightness acuity tester (BAT) and potential acuity meter (PAM) testing (the latter is used to estimate visual potential, especially when posterior segment pathology exists).

• B-scan ultrasonography if unable to visualize the fundus.

• Keratometry and biometry to calculate the IOL implant power before cataract surgery; also consider specular microscopy and pachymetry if cornea guttata or corneal edema exists.

Management

• Cataract extraction and insertion of an IOL is indicated when visual symptoms interfere with daily activities and the patient desires improved visual function, when the cataract causes other ocular diseases (e.g., lens-induced glaucoma, uveitis), or when the cataract prevents examination or treatment of another ocular condition (e.g., diabetic retinopathy, age-related macular degeneration, glaucoma).

• Dilation (tropicamide 1% [Mydriacyl] with or without phenylephrine 2.5% [Mydfrin] tid) may help the patient see around a central opacity in those rare instances when the patient cannot undergo or declines cataract surgery.

Prognosis

Very good; success rate for routine cataract surgery is > 96%; increased risk of complications for posterior polar and traumatic cataracts, pseudoexfoliation syndrome (see below), ectopia lentis, small pupil, intraoperative floppy iris syndrome (IFIS, caused by α1-adrenergic antagonist drugs [i.e., Flomax]).

Posterior Capsular Opacification

Definition

Clouding of the posterior lens capsule after extracapsular cataract extraction.

Epidemiology

After cataract extraction, up to 50% of adult patients may develop posterior capsule opacification; increased incidence in children and patients with uveitis (approaches 100%). IOL material (acrylic) and design (square edge) have reduced the incidence of posterior capsular opacification to less than 10%.

Etiology

Epithelial cell proliferation (Elschnig pearls) and fibrosis of the capsule.

Symptoms

Asymptomatic or may have decreased vision and glare depending on severity and location with respect to the visual axis.

Signs

Posterior capsule opacification; graded on a 1 to 4 scale according to density; may appear as haze, striae, Elschnig pearls, or any combination.

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FIGURE 8-25 Secondary cataract composed of Elschnig pearls.

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FIGURE 8-26 Posterior capsular opacification demonstrating fibrosis of posterior capsule. Also note the anterior capsular opacification and phimosis.

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FIGURE 8-27 Posterior capsule opening following Nd : YAG laser capsulotomy when viewed with retroillumination. Jagged edges or leaflets of the larger anterior capsulotomy are visible, as is the superior edge of the intraocular lens optic from the 12 o’clock to 3 o’clock positions.

Evaluation

• Complete ophthalmic history and eye exam with attention to visual acuity, refraction, cornea, tonometry, gonioscopy, IOL position and stability, posterior capsule, and ophthalmoscopy.

Management

• If visually significant, treat with neodymium : yttrium–aluminum–garnet (Nd : YAG) laser posterior capsulotomy.

• Procedure parameters: A contact lens is used to stabilize the eye and focus the beam better; the goal is to create a central 3–4-mm opening in the posterior capsule; pupil dilation is usually performed but is not always necessary. Laser energy setting is typically 1–3 mJ and is titrated according to tissue response.

• In young children, a primary posterior capsulotomy and anterior vitrectomy are performed at the time of cataract surgery.

Prognosis

Very good; complications of Nd : YAG capsulotomy are rare but include increased intraocular pressure, IOL damage or dislocation, corneal burn, retinal detachment, cystoid macular edema, and hyphema.

Aphakia

Definition

Absence of crystalline lens; usually secondary to surgery, rarely traumatic (total dislocation of crystalline lens [see Figure 8-39]), or very rarely congenital.

Symptoms

Loss of accommodation and decreased uncorrected vision.

Signs

Decreased uncorrected visual acuity (usually very high hyperopia), no lens, iridodonesis; may have a visible surgical wound, peripheral iridectomy, vitreous in the anterior chamber, complications from surgery (bullous keratopathy, increased intraocular pressure, iritis, posterior capsule opacification, cystoid macular edema), or evidence of ocular trauma (see appropriate sections).

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FIGURE 8-28 Aphakia demonstrating absence of the crystalline lens. Pigment cells on the anterior vitreous face are visible.

Evaluation

• Complete ophthalmic history with attention to previous ocular surgery or trauma.

• Complete eye exam with attention to refraction, cornea, tonometry, anterior chamber, gonioscopy, iris, lens, and ophthalmoscopy.

• Consider specular microscopy and pachymetry if cornea guttata or corneal edema exists.

Management

• Proper aphakic correction with contact lens; consider aphakic spectacles if bilateral.

• Consider secondary IOL implantation.

• Treat complications if present.

Prognosis

Usually good; increased risk of retinal detachment, especially for high myopes and if posterior capsule is not intact.

Pseudophakia

Definition

Presence of IOL implant after crystalline lens has been removed; may be inserted primarily or secondarily. There are numerous types of IOLs including: anterior or posterior chamber; rigid or foldable; 1- or 3-piece; loop or plate haptic; round or square edge; polymethylmethacrylate, acrylic, silicone, hydrogel, or collamer; monofocal, multifocal, accommodating, toric, and aspheric.

Symptoms

Asymptomatic; may have decreased vision, loss of accommodation, edge glare, monocular diplopia or polyopia, or induced ametropia with decentered or tilted IOL.

Signs

IOL implant (may be in anterior chamber, iris plane, capsular bag, or ciliary sulcus with or without suture fixation to iris or sclera); may have a visible surgical wound, peripheral iridectomy, complications from surgery (bullous keratopathy, iris capture, decentered IOL, increased intraocular pressure, iritis, hyphema, opacified posterior capsule, cystoid macular edema).

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FIGURE 8-29 Pseudophakia demonstrating posterior chamber intraocular lens (IOL) well centered in the capsular bag. The anterior capsulorrhexis edge has fibrosed and is visible as a white circle overlying the IOL optic; the edges of the IOL haptics where they insert into the optic are also seen.

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FIGURE 8-30 Pseudophakia demonstrating a well-positioned accommodating posterior chamber IOL (Crystalens AO). The capsulorrhexis is visible slightly larger than the optic and overlying the haptic hinges.

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FIGURE 8-31 Pseudophakia demonstrating anterior chamber intraocular lens in good position above the iris.

Evaluation

• Complete ophthalmic history and eye exam with attention to visual acuity, refraction, cornea, anterior chamber, gonioscopy, iris, IOL position and stability, posterior capsule integrity and clarity, and ophthalmoscopy.

Management

• May require correction of refractive error (usually reading glasses).

• Treat complications if present.

Prognosis

Usually good; increased risk of retinal detachment, especially for high myopes and if posterior capsule is not intact.

Exfoliation

Definition

True exfoliation is delamination, or schisis, of the anterior lens capsule into sheet-like lamellae.

Etiology

Infrared and thermal radiation; also senile form.

Epidemiology

Rare; classically occurs in glass blowers.

Symptoms

Asymptomatic.

Signs

Splitting of anterior lens capsule, appears as scrolls; may have posterior subcapsular cataract.

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FIGURE 8-32 True lens exfoliation demonstrating scrolling of split anterior lens capsule (arrowheads).

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FIGURE 8-33 Same patient as Figure 8-32, demonstrating appearance of lens capsule exfoliation as viewed with retroillumination.

Differential Diagnosis

Pseudoexfoliation syndrome.

Evaluation

• Complete ophthalmic history with attention to infrared and thermal radiation exposure.

• Complete eye exam with attention to lens.

Management

• No treatment recommended.

• Prevention by use of protective goggles.

• May require cataract extraction.

Prognosis

Good.

Pseudoexfoliation Syndrome

Definition

Pseudoexfoliation is a generalized disorder of elastin formation that results in the abnormal accumulation of small, gray-white fibrillar aggregates (resembling amyloid) on the lens capsule, iris, anterior segment structures, and systemically (may involve the skin, heart, and lungs).

Epidemiology

Usually asymmetric, bilateral more often than unilateral. Occurs in all racial groups, common in Scandinavians, South African Blacks, Navaho Indians, and Australian Aborigines; almost absent in Eskimos. Age-related, rare in individuals under 50 years old, incidence increases after age 60 years (4–6% in patients over 60 years old). Up to 60% develop ocular hypertension or glaucoma (see below); in the United States, 20% have elevated intraocular pressure at initial examination, and 15% develop it within 10 years. Mapped to chromosome 15q24 (LOXL1 gene).

Symptoms

Asymptomatic.

Signs

Loss of pupillary ruff, iris transillumination defects, pigment deposits on the iris, trabecular meshwork, and anterior to Schwalbe’s line (Sampaolesi’s line); target pattern of exfoliative material on lens capsule (central disc and peripheral ring with intervening clear area); white exfoliation material is also seen on zonules, anterior hyaloid, iris, and pupillary margin; shallow anterior chamber due to forward displacement of the lens–iris diaphragm; may have phacodonesis, cataract (40%), or signs of glaucoma with increased intraocular pressure, optic nerve cupping, nerve fiber layer defects, and visual field defects.

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FIGURE 8-34 Exfoliative material on the anterior lens surface in typical pattern of central disc and peripheral ring in a patient with pseudoexfoliation syndrome.

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FIGURE 8-35 Central disc and peripheral ring of exfoliative material as seen with retroillumination.

Evaluation

• Complete ophthalmic history and eye exam with attention to tonometry, anterior chamber, gonioscopy, iris, lens, and ophthalmoscopy.

• Check visual fields in patients with elevated intraocular pressure or optic nerve cupping to rule out glaucoma.

Management

• Observe for pseudoexfoliation glaucoma by monitoring intraocular pressure.

• May require treatment of increased intraocular pressure (see Primary Open-Angle Glaucoma section in Chapter 11) and pseudoexfoliation glaucoma (see below).

Prognosis

Good; poorer if pseudoexfoliation glaucoma develops; increased incidence of complications at cataract surgery due to weak zonules and increased lens mobility.

Pseudoexfoliation Glaucoma

Definition

A form of secondary open-angle glaucoma associated with pseudoexfoliation syndrome.

Epidemiology

Most common cause of secondary open-angle glaucoma; affects 2% of US population over 50 years old. Up to 60% with pseudoexfoliation syndrome develop ocular hypertension or glaucoma; 50–60% bilateral, often asymmetric; age-related (rare in individuals under 50 years old, increases after age 60 years). Mapped to chromosome 15q24 (LOXL1 gene).

Mechanism

(1) Trabecular meshwork (TM) dysfunction due to obstruction by exfoliative material. The exfoliative material may flow into the TM from the anterior chamber, or it may be produced in the TM.

(2) Abnormally weak lamina cribrosa (composed of elastin) that renders the optic nerve more susceptible to elevated IOP.

Symptoms

Asymptomatic; may have decreased vision or constricted visual fields in late stages.

Signs

Normal or decreased visual acuity, increased intraocular pressure (can be very high and asymmetric); similar ocular signs as in pseudoexfoliation syndrome (see above), optic nerve cupping, nerve fiber layer defects, and visual field defects.

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FIGURE 8-36 Patient with pseudoexfoliation glaucoma demonstrating peripheral ring of exfoliative material on the lens surface with bridging band connecting to the central disc.

Differential Diagnosis

Primary open-angle glaucoma, other forms of secondary open-angle glaucoma.

Evaluation

• Complete ophthalmic history and eye exam with attention to tonometry, anterior chamber, gonioscopy, iris, lens, and ophthalmoscopy.

• Check visual fields.

• Stereo optic nerve photos are useful for comparison at subsequent evaluations.

Management

• Choice and order of topical glaucoma medications depend on many factors, including patient’s age, intraocular pressure level and control, and amount and progression of optic nerve cupping and visual field defects. Treatment options are presented in the Primary Open-Angle Glaucoma section (see Chapter 11); more resistant to treatment than primary open-angle glaucoma.

• Laser trabeculoplasty is effective, but action may be short-lived.

• May require glaucoma filtering procedure if medical treatment fails.

Prognosis

Poorer than primary open-angle glaucoma; increased incidence of angle-closure; lens removal has no effect on progression of disease; increased incidence of complications at cataract surgery due to weak zonules (composed of elastin) and increased lens mobility.

Lens-Induced Glaucoma

Definition

Secondary glaucoma due to lens-induced abnormalities.

Etiology/ mechanism

Lens Particle

Retained cortex or nucleus after cataract surgery or penetrating trauma causes inflammatory reaction and obstructs trabecular meshwork; more anterior segment inflammation than phacolytic.

Phacolytic

Lens proteins from hypermature cataract leak through intact capsule and are ingested by macrophages; can occur with intact, dislocated lens; lens proteins and macrophages obstruct trabecular meshwork.

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FIGURE 8-37 Phacolytic glaucoma demonstrating mature white cataract with anterior chamber inflammation.

Phacomorphic

Enlarged, cataractous lens pushes the iris forward, causing secondary angle-closure (see Chapter 6).

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FIGURE 8-38 Phacomorphic angle-closure glaucoma due to intumescent cataract pushing the iris forward and thereby obstructing the trabecular meshwork.

Symptoms

Decreased vision, pain, photophobia, red eye; may have halos around lights and other symptoms of angle-closure glaucoma (see Chapter 6); may have constricted visual fields.

Signs

Decreased visual acuity, increased intraocular pressure, ciliary injection, anterior chamber cells and flare, peripheral anterior synechiae, cataract or residual lens material, signs of recent surgery or trauma including surgical wounds, sutures, and signs of an open globe (see Chapter 4); may have optic nerve cupping, nerve fiber layer defects, and visual field defects.

Differential Diagnosis

See above; other forms of secondary glaucoma, uveitis, endophthalmitis.

Evaluation

• Complete ophthalmic history and eye exam with attention to cornea, tonometry, anterior chamber, gonioscopy, iris, lens, and ophthalmoscopy.

• B-scan ultrasonography if unable to visualize the fundus.

• Check visual fields.

Management

• Topical steroid (prednisolone acetate 1% up to q1h) and cycloplegic (cyclopentolate 1% or scopolamine 0.25% bid to tid).

• Treatment of increased intraocular pressure (see Primary Open-Angle Glaucoma and Angle-Closure Glaucoma sections in Chapters 11 and 6, respectively).

• Definitive treatment consists of surgical lens extraction or removal of retained lens fragments.

• May require glaucoma filtering procedure.

Prognosis

Good if definitive treatment is performed early and pressure control is achieved.

Dislocated Lens (Ectopia Lentis)

Definition

Congenital, developmental, or acquired displacement of the crystalline lens; may be incomplete (subluxation) or complete (luxation) dislocation of the lens into the anterior chamber or vitreous.

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FIGURE 8-39 Dislocated crystalline lens resting on the retina.

Etiology

Ectopia Lentis et Pupillae (AR)

Associated with oval or slit-like pupils; pupil displacement is in opposite direction of the lens displacement.

Homocystinuria (AR)

Enzymatic disorder of methionine metabolism with elevated levels of homocystine and methionine; direction of lens displacement is typically down and in. Not present at birth; progressive thereafter, with more than 90% having dislocated lenses by the third decade. Patients develop seizures, osteoporosis, mental retardation, and thromboembolism.

Hyperlysinemia

Inability to metabolize lysine; lens subluxation, muscular hypotony, and mental retardation.

Marfan’s Syndrome (AD)

Usually bilateral; occurs in about two-thirds of Marfan’s patients due to defective zonules; direction of lens displacement is typically up and out. Other signs include marfanoid habitus with disproportionate growth of extremities, arachnodactyly, joint laxity, pectus deformities, scoliosis, and increasing dilation of the ascending aorta with aortic insufficiency (may cause death). Mapped to chromosome 15q (FBN1[fibrillin-1] gene).

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FIGURE 8-40 Lens subluxed (upward) in a patient with Marfan’s syndrome.

Microspherophakia

Small spheric lens; occurs as an isolated anomaly or as part of a syndrome (i.e., dominant spherophakia, Weill–Marchesani syndrome, Lowe’s syndrome, Alport’s syndrome, Peter’s anomaly, rubella); direction of lens displacement is often inferiorly or anteriorly.

Simple Ectopia Lentis (AD)

Often present at birth; lens is small and spheric (microphakic and spherophakic); direction of lens displacement is typically up and out.

Sulfite Oxidase Deficiency (AR)

Error of sulfur metabolism with ectopia lentis, seizures, and mental retardation.

Other

Aniridia, Ehlers–Danlos syndrome, trauma, syphilis, pseudoexfoliation syndrome, megalocornea.

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FIGURE 8-41 Subluxed lens (up and out) due to trauma. Note broken inferior zonular fibers.

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FIGURE 8-42 Lens subluxed (downward) due to trauma.

Epidemiology

Most common cause of lens subluxation or luxation is trauma (up to 50%); associated with cataract and rhegmatogenous retinal detachment. Most frequent cause of heritable lens dislocation is Marfan’s syndrome.

Symptoms

Asymptomatic; may have decreased vision, diplopia, symptoms of angle-closure glaucoma (see Chapter 6).

Signs

Normal or decreased visual acuity, subluxated or luxated lens, phacodonesis, iridodonesis; may have increased intraocular pressure, anterior chamber cells and flare, vitreous in the anterior chamber, iris transillumination defects, angle abnormalities, and other signs of ocular trauma.

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FIGURE 8-43 Dislocated lens in the anterior chamber. The edge of the clear lens is visible overlying the iris.

Differential Diagnosis

See above.

Evaluation

• Complete ophthalmic history and eye exam with attention to visual acuity, refraction, corneal diameter, tonometry, anterior chamber, gonioscopy, iris, and lens.

• Consider B-scan ultrasonography if unable to visualize the fundus.

• Lab tests: Venereal Disease Research Laboratory (VDRL) test, fluorescent Treponema antibody absorption (FTA-ABS) test, and lumbar puncture if syphilis suspected.

• Medical consultation for systemic diseases.

Management

• Correct any refractive error.

• Consider lens extraction.

• May require treatment of angle-closure glaucoma (see Secondary Angle-Closure Glaucoma section in Chapter 6); miotic agents may exacerbate pupillary block and should be avoided. Microspherophakia causing pupillary block is treated with a cycloplegic (scopolamine 0.25% tid or atropine 1% bid); may also require laser iridotomy.

• Treat underlying disorder (e.g., dietary restriction in homocystinuria, IV penicillin for syphilis).

Prognosis

Depends on etiology.