Cataract Surgery, 3rd Edition

PART V – Special Techniques for Cataract Extraction

Chapter 27 – The Intumescent Cataract

Roger F. Steinert, MD


Contents

  

   

Clinical Presentation

  

   

Absence of the Red Reflex

  

   

Thinning and Weakening of the Posterior Capsule

  

   

Weak or Absent Zonules

  

   

The Nucleus

  

   

Conclusion

CHAPTER HIGHLIGHTS

  

   

Hydration changes in the lens capsule

  

   

Techniques for capsular dye staining

  

   

Issues with zonules and the nucleus

Surgical removal of an intumescent lens presents several special challenges to the surgeon. An intumescent lens is a lens that has begun to lose structural integrity; the protein is denatured to the point that the lens is becoming hydrating. The capsule is thinner and more fragile, the red reflex is absent, zonules may be weakened or absent, and the nucleus is often large and hard if the intumescence occurs in an age-related cataract.

Clinical presentation

A crystalline lens in which the cortex has become extensively hydrated, with white opacification, is historically known as a mature cataract. A mature lens that is swollen to the point of obstructing aqueous flow through the pupil and/or physically crowding the anterior chamber and angle is causing phacomorphic glaucoma. If the nucleus has sunk off-center in the lens as a result of liquefaction of the cortex, it is known as morgagnian. If the process is so advanced that some hydrated and denatured protein has begun to slowly leave the capsular bag, resulting in wrinkles in the no longer distended bag, the cataract is called hypermature. If the capsule loses integrity so that macrophages are attracted to scavenge the lens protein that has been released out of the capsular bag, phacolytic glaucoma may result from obstruction of the trabecular outflow. Severe inflammation caused by the released lens protein is called phacoanaphylaxis.

Some cases of intumescent cataract are due to physical damage to the capsule. A frank traumatic break in the capsule will result in rapid hydration and opacification of the cortex. A small break, particularly a puncture, will occasionally seal itself and result in only a local opacity. Physical damage to the capsule usually occurs in the setting of a perforating or severe blunt trauma or from intraocular surgery, particularly pars plana vitrectomy. Zonules are often damaged in this same process.

In mature and hypermature cataracts, the anterior capsule may undergo degeneration, with deposition of calcium or development of focal dense plaques. Dense postinflammatory plaques are particularly common after blunt trauma that triggers an intumescent cataract (Figure 27-1). If present, these areas will interfere with a normal capsulorrhexis tear. The surgeon will need to direct the tear around these abnormalities, if possible, or use another technique, such as a Gills-Vannas scissors, to cut across these densities.

 

 

Figure 27-1  A, Intumescent traumatic cataract. Note the loss of zonules in the upper right. B, Trypan blue staining of the anterior capsule reveals a dense, darker staining plaque on the anterior capsule that will not tear with a conventional capsulorhexis technique. C and D, Gills-Vannas scissors must be used to cut through the anterior capsular plaque.

 

 

As part of the preoperative evaluation of a patient with an intumescent cataract, the surgeon should ask about past ocular history that might alter the surgical approach, obtain past medical records if possible, perform further nonroutine preoperative testing, and discuss with the patient that the potential for surgical complications is increased and the prognosis for full recovery of vision is uncertain. In particular, the surgeon must try to answer the questions: “Why did the patient wait so long before presenting?” Is the eye densely amblyopic, or was useful vision lost years earlier to a process such as a retinal vascular occlusion or retinal detachment? Did the patient suffer traumatic maculopathy or optic neuropathy? In most cases of an intumescent lens, where the fundus cannot be seen, a B-scan ultrasound is indicated. Other helpful evaluations include testing for entoptic imagery, perception of colored lights, gross visual field examination with a point light source, and bright flash visual-evoked response. Usually these tests do not provide a highly accurate prognosis of visual potential, but they may help determine the potential value of surgery in patients with questionable past histories.

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Absence of the red reflex

The largest challenge in removal of the intumescent cataract is the absence of a red fundus reflex when the cataract is viewed through the operating microscope.[1] If the surgeon intends to perform phacoemulsification with placement of an intraocular lens (IOL) in the capsular bag, an intact capsulorrhexis is critical in maintaining structural integrity.[2] If the surgeon's intention is to perform an extracapsular cataract extraction and express the nucleus, then a can-opener style of anterior capsulotomy may be acceptable. Even then, however, it is nearly impossible to avoid large capsule flaps and the potential for equatorial and posterior tears unless the anterior capsule can be visualized.

Surgeons have used several approaches to improve visualization of the anterior capsule in the absence of the red reflex, most notably employing oblique illumination from another instrument such as a fiberoptic light pipe.[3] In addition, when the anterior capsule is opened and white cortex clouds the surgeon's view, the surgeon should pause the capsulotomy and improve the view, either by adding more viscoelastic or using the irrigation–aspiration device to remove the obscuring cortex while taking care not to engage the capsule.

The most important advance in managing the anterior capsule in the absence of a red reflex is the use of an anterior capsule stain. Surgeons have attempted to stain the anterior capsule with a variety of substances. Fluorescein sodium 2% weakly stains the anterior capsule on the exterior surface and has slightly stronger uptake on the inner (epithelial) surface if it is injected after an initial opening into the capsular bag.[4] Cobalt blue illumination, not generally available on most operating microscopes, may be necessary to visualize the stain.[5] Some other commonly available stains, such as methylene blue and gentian violet, are toxic to the endothelium, at least in many common formulations.[6] The patient's own blood has been applied to the capsule as a method of staining as well.[7]

Two dyes are available that have been proven safe and effective for staining the anterior capsule. Horiguchi et al.[8] elegantly demonstrated both the endothelial safety and also the effective technique for safely dissolving, diluting, and applying indocyanine green to the anterior capsule. Melles et al.[9] have developed a commercial preparation of trypan blue (VisionBlue, DORC, Zuidland, Holland) that is also safe and effective. In the original version of these techniques, the dye is applied under an air bubble that fills the anterior chamber, in order not to dilute the dye. The dye is applied as one or two microdrops wiped across the anterior capsule under the air bubble from a 27- or 30-gauge cannula. The air bubble itself, although preventing dye dilution by aqueous humor in the anterior chamber, prevents the dye from contacting the anterior capsule; therefore, the cannula is used to wipe the dye under the air bubble and across the anterior capsule. The air bubble is then replaced with viscoelastic, and the capsulotomy is performed in the usual manner (Figure 27-2).

     

 

Figure 27-2  A, Intraoperative photographs of a mature white cataract with anterior capsule staining by trypan blue. B, Injection of air bubble through paracentesis. C, Trypan blue dye is applied under an air bubble filling the anterior chamber, using a blunt-tip cannula to inject and wipe the stain across the anterior capsule. D, Capsulorrhexis proceeds normally, with clear visualization as a result of the staining. E, During phacoemulsification, the surgeon can visualize the stained anterior capsule edge, reducing the potential for inadvertent damage by the phaco tip. F, After intraocular lens (IOL) implantation, the stained anterior capsule can be seen overlying the IOL optic.

 

 

An alternative to the air bubble technique is the use of a high concentration cohesive ophthalmic viscoelastic device, most commonly Healon 5 (Advanced Medical Optics). The surgeon must avoid injection of more than the minimum amount of dye necessary to stain the capsule. Otherwise, free dye in the anterior chamber surrounding the bolus of Healon 5 may obscure visualization of the anterior capsule and require washout of the anterior chamber and reinstillation of viscoelastic to perform the capsulorrhexis. However, in the author's experience, Healon 5 allows better contact of the dye with the anterior capsule compared with an air bubble (Figure 27-3). More intense anterior capsule staining results. In addition, there is no need to perform the steps of injecting air and later exchanging the air bubble for the viscoelastic agent to perform the anterior capsulotomy.

    

 

Figure 27-3  Application of trypan blue stain under a dome of Healon 5. A, Cannula is wiped across the anterior capsule while the stain is injected into the space created between the capsule and the Healon 5. B, If the dye does not mix with the solid mass of Healon 5 and the surgeon avoids injecting excess dye, visualization is adequate to proceed with the capsulorrhexis without washing out the Healon 5 and replacing it.

 

 

Some surgeons simply inject enough trypan blue into the anterior chamber to overcome initial dilution and thereby directly stain the capsule. The surgeon must be aware that if the corneal endothelium is diseased, however, especially in Fuch's dystrophy, the posterior cornea will take up the dye and impair the surgeon's view of the cataract.

With either the air bubble or Healon 5 technique, the dye should be left in contact with the anterior capsule for at least 1min before performing the anterior capsulotomy to obtain adequately intense staining of the anterior capsule.

In addition to facilitating the capsulotomy, the dye-enhanced visualization of the capsule often proves helpful in avoiding operative trauma to the capsulorrhexis edge by the phacoemulsification instruments (see Figure 27-2E and F).

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Thinning and weakening of the posterior capsule

Many clinicians have the clinical impression that the posterior capsule presents increased challenges in the surgery of an intumescent lens. More prolonged phacoemulsification time and manipulation of a large and hard nucleus explain only part of the reason for increased frequency of posterior capsule complications.

The posterior capsule is often thinned and stretched by the expanded intumescent lens. As a result, the surgeon is faced with a posterior capsule that is not only weak but also flaccid, with wrinkles and a laxity that makes it prone to come up to the phaco tip and be ruptured. This problem is worsened by the absence of any epinucleus that protects the posterior capsule. A useful step is to inject a dispersive, noncohesive viscoelastic behind the nucleus one or more times during the phacoemulsification. This will provide an artificial epinucleus to keep the posterior capsule back from the operative plane and also stabilize the nucleus against tumbling.

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Weak or absent zonules

Zonular weakness or frank absence of zonules sometimes presents a challenge during surgery on an intumescent cataract. Usually this occurs either because the patient is elderly, when zonules typically weaken as part of the aging process, or because the cataract has been induced by trauma.

As soon as clinically significant zonular weakness is suspected, placement of a Witschell capsular tension ring (Morcher GmbH) is advised. If the loss of zonules is severe, with major instability of the capsular bag, then the Cionni modification of the capsule tension ring allows the surgeon to directly add stabilization with an ab interno polypropylene transscleral suture (see Chapter 29).

If the capsular bag and/or sulcus are/is compromised to the point where the ability to support an IOL long term is uncertain, then a transscleral sutured posterior chamber IOL or an anterior chamber IOL should be implanted (see Chapter 41).

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The nucleus

In a relatively young patient with an intumescent lens, the hydration that opacifies the cortex will also lead to softening of the immature nucleus. The nucleus will then aspirate or require minimal ultrasound for removal. In elderly patients, however, the nucleus is often quite sclerotic and large. Because the cortex is already hydrated, hydrodissection and hydrodelineation are unnecessary. The removal of a large, hard nucleus is covered in Chapter 28 and is not discussed here. Caution must be taken in view of the weak posterior capsule and zonules.

In some advanced cases of intumescence, the nucleus itself will begin to hydrate slightly. These mildly hydrated nuclei typically have a characteristic golden haze rather than the dark brown, molasses color of a dense and aged nucleus. Although the nucleus will not soften to the point of being removable with aspiration alone, it will split more readily with chopping or cracking techniques and not be encumbered by a leathery posterior epinucleus, unlike a dark brown nucleus.

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Conclusion

The intumescent cataract presents some special surgical challenges, most notably in visualizing the anterior capsule and protecting potentially weakened zonules and posterior capsule.

With the advent of staining of the anterior capsule to ensure visibility during surgery and with increasingly atraumatic phacoemulsification techniques, supplemented by use of viscoelastics, capsule tension rings, and transscleral sutures, the removal of an intumescent cataract is a surgical challenge that frequently has a successful outcome.

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References

[1]. Gimbel H.V., Willerscheidt A.B.: What to do with a limited view: the intumescent cataract.  J Cataract Refract Surg  1993; 19:657-661.

[2]. Gimbel H.V., Neuhann T.: Development, advantages, and methods of the continuous circular capsulorrhexis technique.  J Cataract Refract Surg  1990; 16:31-37.

[3]. Mansour A.M.: Anterior capsulorrhexis in hypermature cataracts.  J Cataract Refract Surg  1993; 19:116-117.letter

[4]. Hoffer K.J., McFarland J.E.: Intracameral subcapsular fluorescein staining for improved visualization during capsulorrhexis in mature cataracts.  J Cataract Refract Surg  1993; 19:566.[letter]

[5]. Fritz W.L.: Fluorescein blue light-assisted capsulorrhexis for mature or hypermature cataract.  J Cataract Refract Surg  1998; 24:19-20.

[6]. Perez A.R., Vainer A.I.: Capsular dyes,  Calif: San Diego; April 1998.

[7]. Cimetta D.J., Gatti M., Lobianco G.: Haemocoloration of the anterior capsule in white cataract CCC.  Eur J Implant Refract Surg  1995; 7:184-185.

[8]. Horiguchi M., Miyake K., Ohta I., et al: Staining of the lens capsule for circular continuous capsulorrhexis in eyes with white cataract.  Arch Ophthalmol  1998; 116:535-537.

[9]. Melles G.R.J., de Waard P.W.T., Pameyer J.H., et al: Trypan blue capsule staining to visualize the capsulorrhexis in cataract surgery.  J Cataract Refract Surg  1999; 25:7-9.