The first thing to consider is visual rehabilitation as the patient is unable to function in accord with her needs and has a central PSC. The perception of reduced acuity may come from 4 sources: the PSC, light scatter from the iris defects, the down-drawn iris covering the visual axis, and possibly the corneal endothelial changes associated with the syndrome.
Before cataract surgery is considered, it would be helpful to advise the patient that the cataract is only part of the visual problem and that cataract removal is unlikely to completely resolve her visual symptoms. Furthermore, cataract surgery may worsen vision as a result of the onset of corneal edema; these eyes have a dysfunctional corneal endothelium at risk for corneal decompensation.
The second issue is that IOP control requires the use of 4 medications. It would be tempting to resolve the pressure problem by doing a combined cataract and glaucoma procedure. However, there is no apparent optic nerve damage, and the visual field is full. In addition, if the patient decides to proceed with glaucoma filtering surgery, resolution of the IOP problem with a single procedure is far from ensured in an eye with ICE syndrome.
In a recent study, 4 of 10 eyes with an aqueous shunt had pressure control (IOP less than 21 mm Hg).1 In another study, after trabeculectomy 12 of 22 eyes had successful control subsequent to initial surgery.2 Furthermore procedures in these eyes are subject to ongoing remodeling associated with endothelial cell proliferation and migration, even with the use of antimetabolites.3
In aqueous shunt surgery, the optimal placement of the tube is problematic. Iris changes can cause tube displacement, resulting in occlusion from iris tissue or ICE membranes; the same mechanisms can cause tube–corneal touch.1 Even early and intermediate-term successes face ongoing risks of bleb failure. Because of these issues, we cannot ensure the patient with much conviction that there will be long-term resolution of the IOP problem by a single filtering surgery. By avoiding filtering surgery now, it might be possible to spare the patient the associated problems for a few more years.
With current temporal clear corneal surgery, the conjunctiva is not typically disturbed, permitting later filtering surgery without an altered prognosis. Given controlled IOPs, a normal optic disc, a full field, and a rather poor prognosis for filtration surgery, I would suggest initially doing cataract surgery alone. This action would be tempered if the patient had strong objections to the use of multiple medications.
For the cataract portion of the procedure, I would perform temporal clear corneal phacoemulsification. A paracentesis would be made in the inferior quadrant directly opposite the apex of the down-drawn pupil. After introduction of a viscoelastic agent, a radial iris incision would be created at the apex of the area of the down-drawn pupil with a Vannas scissors. The iris incision would be advanced upward sufficiently to ensure adequate exposure for a capsulorhexis. No attempt would be made to close the sphinterotomy as the iris in these eyes is too friable to permit satisfactory closure. Although, in general, I do not close cataract incisions after clear corneal surgery, I would in this case, using a continuous shoelace 10-nylon suture to limit the risk of the incision opening with manipulations that might be necessary during subsequent filtering surgery.
If the patient objects strenuously to the use of medications, I would do a 2-site combined procedure. After temporal clear corneal cataract surgery, filtering surgery would be done in the superior nasal quadrant. A limbal-based flap would be used. After the scleral flap is created, a 4.0 × 6.0 mm Polypore™ instrument sponge soaked in mitomycin 0.3 mg/mL would be placed over the flap for 3 minutes and the area then irrigated copiously with a balanced salt solution. The trabeculectomy would then be completed in the standard fashion. If the initial trabeculectomy failed, I would consider placing an aqueous tube shunt in the temporal quadrant.
1. Kim DK, Aslanides IM, Schmidt CM Jr, et al. Long-term outcome of aqueous shunt surgery in ten patients with iridocorneal endothelial syndrome. Ophthalmology 1999; 106:1030-1034
2. Kidd M, Hetherington J, Magee S. Surgical results in iridocorneal endothelial syndrome. Arch Ophthalmol 1988; 106:199-201
3. Wright MM, Grajewski AL, Cristol SM, Parrish RK. 5-fluorouracil after trabeculectomy in the iridocorneal endothelial syndrome. Ophthalmology 1991; 98:314-316