eMedicine Specialties > Ophthalmology > Lens

Posterior Polar Cataract: Treatment

Author: George Plechaty, MD, Clinical Assistant Professor, Department of Surgery, Division of Ophthalmology, University of Hawaii School of Medicine
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Updated: Jun 22, 2007

Treatment

Medical Therapy

Therapy for posterior polar cataracts is primarily surgical, but safety is a consideration since this entity poses a special challenge. The timing of the intervention should be early enough to prevent the development of amblyopia.

A thorough pediatric and/or intermedical evaluation for associated systemic findings in all forms of congenital cataract, including posterior polar cataracts, is indicated. Kronenberg and colleagues reported on a rare syndrome with a rare neurocutaneous syndrome in which a chart review revealed significant eye abnormalities.¹³ Duke-Elder cited a series of associated conditions, including ectodermal dysplasia, Rothmund disease, scleroderma, incontinentia pigmenti, congenital dyskeratosis, congenital ichthyosis, and congenital atrophy of the skin.⁶

Surgical Therapy

Posterior polar cataract surgery has posed to be challenging even with the most advanced techniques available. The surgical pitfalls have been well documented in the ophthalmic literature. The importance of being aware of these surgical pitfalls and avoiding them cannot be overemphasized.

Preoperative Details

The preoperative clearance for posterior polar cataract surgery does not need to include more than that obtained prior to a routine cataract surgery.

A full and careful pediatric workup should be obtained with an emphasis on uncovering any associated systemic abnormalities. Appropriate subspecialty referrals should be obtained in the event of any significant findings.

Assuming the absence of any associated systemic or ocular disease, the preoperative preparation for posterior polar cataract surgery can be limited to a routine preoperative workup and clearance.

Intraoperative Details

Posterior polar cataract surgery is associated with an increased incidence of posterior capsular rupture. Undue stress on the capsule must be minimized. The main difficulty is the adherence of the abnormally formed lens fibers to the posterior capsule and its associated weakness. Once the surgeon is aware of these dangers, the technique can be altered to meet these challenges.

For this reason, special lower flow and aspiration settings should be used. This situation is described in the following case, which is used for illustrative purposes. Topical 4% Xylocaine anesthesia is instilled prior to inserting the lid speculum and positioning the eye to the operative microscope. The cataract is inspected and typically presents as a central posterior discoid mass. This can be surrounded by an area of degenerated fibrillar elements (see Media file 1).

A limbal side port incision can be used to instill 1% preservative-free Xylocaine solution into the anterior chamber.

Surgery begins in the usual manner with a clear corneal incision and capsulorrhexis. Care should be taken to minimize posterior pressure during all maneuvers.

Hydrodelineation should be avoided because the fluid wave created may extend to the weak area of the posterior capsule and in itself produce a tear. Rotation of the cataract should also be avoided to prevent the application of any inadvertent torquing forces being transmitted to the posterior capsule.

Instead, the nucleus and the cortex should be outlined using hydrodissection. The goal is to leave the posterior pole as undisturbed as possible by creating a hydrodissected plane separating the nucleus and the epinucleus. This should create a cushion of the cortex and the epinucleus, which should then cushion and protect the region of the central posterior capsule.

The anterior cortex and the nucleus are then removed using low aspiration and as little phacoemulsification as possible. Moreover, once the nucleus is removed, irrigation and aspiration, and especially phaco, should be directed obliquely as much as possible. Direct application of these forces to the posterior polar cataract should be avoided. These forces should be aimed obliquely so as not to cause inadvertent stress on the delicate posterior capsule. Indeed, it is sometimes possible to hydrodissect part of the discoid opacity free to the point where it can be safely removed (see Media file 2).

Once this is achieved, the surgeon is still faced with the epinucleus and, more significantly, any residual posterior capsular adhesion. Dye has been introduced as an aid to ocular surgery.¹² As seen in Media file 3, the peripheral remnant of the opacity still remains. This presents the possibility of an area of capsular adherence, and care must still be exercised in aspirating this area.

For this reason, highly diluted fluorescein has been instilled to delineate this remnant of the posterior polar cataract. Indeed, the appearance of this remnant is enhanced, and the 2- and 9-o'clock positions of the ring look especially suspicious (see Media file 3). Further, the integrity of the posterior capsule is verified because the dye has not spread into the region of the anterior vitreous.

Additional indirect irrigation can be used to further loosen and hydrate the remaining opacity using the silicone tip, which is an additional recommended safety feature. The remainder of the epinuclear cortex can then be aspirated, using vacuum levels as low as practical to avoid any additional stress (see Media file 4).

Finally, once aspiration has been completed, the posterior chamber intraocular lens can be implanted in the surgeon's usual fashion (see Media file 5). When using a viscoelastic, as during the entire case, care must be taken to avoid overpressurization of the anterior chamber, creating undue posterior force.

If the capsular opacity resists removal in the above maneuver, the surgeon may have to resort to a controlled posterior capsulorrhexis combined with a shallow anterior vitrectomy.  

Postoperative Details

The patient should be examined the day after surgery, and the clarity of the cornea and the depth of the chamber should be assessed. Any complications should also be addressed.

A topical fourth-generation fluoroquinolone antibiotic as well as a nonsteroidal anti-inflammatory drug (NSAID) may be instilled.

A refraction is performed 6 weeks postoperatively; at which time, the eye should be well healed.

Follow-up

Once the eye has stabilized and no problems are present, the patient can be seen 3 months postoperatively and every 6 months thereafter.

Complications

The complications of wound leak, malpositioned IOLs, and endophthalmitis are well known and do occur in cases of posterior polar cataract surgery.

Moreover, since this entity occurs in a young age group, refractive errors tend to increase with age. The choice of IOL power should take this tendency into account. The necessity of lens exchange in these patients has not been documented but should be avoided as much as possible.

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