argon laser peripheral iridoplasty should be performed to widen the angle.263,332 Long-term follow-up in patients with plateau iris

syndrome suggests that peripheral iridoplasty is quite effective in both opening the angle and preventing progression; however, some patients may require retreatment, so long-term monitoring is necessary.265 If iridoplasty plus medical therapy cannot control the IOP adequately, then trabeculectomy, other filtration surgery, or glaucoma drainage devices should be considered; care is needed, as these patients are at risk for ciliary block glaucoma (aqueous misdirection syndrome). Cataract extraction with IOL implant has also been described as effective in allowing the ciliary processes to move posteriorly and improve pressure control;333 but apposition has been documented to persist even after lens removal.104

Pseudoplateau iris (cysts of the iris and ciliary body)

Primary cysts of the iris and ciliary body usually arise from the epithelial layers.The cysts can be single or multiple and involve one or both eyes. In most cases the cysts remain stationary and cause no harm.334 In rare cases the cysts are sufficient in size and number

to lift the iris forward and cause angle-closure glaucoma without pupillary block.335,336 As noted above, this condition appears clini-

cally identical to plateau iris but is caused by peripheral iris or ciliary body pigment epithelial cysts (or rarely a ciliary body tumor) pushing the peripheral iris forward causing angle closure and potential glaucoma.322 The syndrome of iris cysts and angle-closure glaucoma has been reported in a few families in whom it is inherited in an autosomal dominant pattern.337

Iris cysts are usually dark brown and may be visible through an iridectomy or at the pupillary margin, especially when the pupil is dilated. Ciliary body cysts are often less pigmented and are difficult to see unless they are quite large. The presence of the cysts gives the iris surface an undulating or irregular appearance.The anterior chamber is uneven in depth, and the angle is variable in width.The diagnosis of pseudoplateau iris or angle closure caused by iris or ciliary body cysts can only be confirmed by UBM. Peripheral iridoplasty has been described as sometimes effective.338

Once diagnosed, angle-closure glaucoma associated with cysts of the iris or ciliary body may be found to manifest an acute or chronic time course. If the cysts causing angle closure are visible, they can be punctured with an argon or Nd:YAG laser.Argon laser settings of 50–100  m, 0.1–0.2 seconds, and 200–1000 mW are used to collapse the cysts and free their fluid (which is well tolerated by the eye). Nd:YAG settings are similar to iridotomy. It may be necessary to repeat the laser treatment if the cysts reform.339 If the cysts are not visible at the pupillary margin, it is possible to puncture them by first doing a laser iridotomy over the involved area, especially if UBM has identified their location.340 This technique is suitable when a few large cysts cause angle closure; it would not be suitable when multiple small cysts are present. Nonpigmented cysts of the ciliary body can be punctured with the Nd:YAG laser. Medical therapy may be required after cyst puncture if extensive PAS are present. In a few cases the cysts cannot be treated with a laser, and filtering surgery is necessary.

Secondary cysts of the iris and ciliary body may be caused by trauma, tumors, or congenital syphilis.341 The cysts may cause glaucoma by the mechanism described above, or they may be associated with glaucoma on the basis of inflammation or neovascularization.

3. PHACOMORPHIC GLAUCOMA

This third category of PACG mechanisms embraces a variety of situations where an abnormal lens either compromises the lens–iris

channel (pupillary block) or mechanically pushes the peripheral iris forward into the angle structures. Though the term phacomorphic glaucoma is often reserved for intumescent cataracts which crowd the anterior segment, technically the Greek etymology refers to ‘lens-shape’ or ‘lens-form’, the common denominator among several lens-related angle-closure glaucomas. (Pupillary block from secondary causes, such as uveitis, are not per se related to anomalous lens structure or positioning, and are addressed in Ch. 16.) Such distinctive conditions of an aberrant lens – from swelling, dislocation or subluxation – often require a laser iridotomy in an attempt to eliminate any pupillary block component, and can be imaged with UBM to clarify the anomalous anatomy.

Intumescent and swollen lens

Increased pupillary block can develop slowly with an age-related cataract or rapidly with a traumatic, swollen cataract. Pupillary block may not be the sole mechanism of angle closure because the enlarging lens may also push the peripheral iris forward into the angle.342 Phacomorphic glaucoma is often seen in eyes that were traumatized in the past and that have limited vision.This condition is usually unilateral and resembles PACG, except for the presence of an intumescent lens and a normal anterior chamber depth in the fellow eye.

The immediate medical treatment for phacomorphic glaucoma is identical to that outlined earlier in this chapter for managing PACG. The goals of medical treatment are to open the angle and reduce the IOP to a level that permits corneal clarity for laser, or to lower pressures for safer incisional surgery. The definitive treatment for this condition is cataract extraction. If cataract extraction is not possible because of extenuating circumstances (e.g., gravely ill patient) or must be delayed, iridotomy should be performed. Iridotomy may not be curative in all cases, especially those in which direct pressure from the lens is playing a greater role than is pupillary block. Yet one study showed excellent effectiveness of Nd:YAG iridotomy in breaking the acute attack of angle-closure glaucoma and allowing the inflammation to improve prior to cataract surgery.343

Angle-closure glaucoma from a swollen lens has been described as an idiosyncratic response to a variety of systemic medications, including the sulfonamide drugs and their derivatives, the carbonic anhydrase inhibitors,344–346 thiazide diuretics,347 tetracycline,348 prochlorperazine,349 spironolactone,350 phenformin, acetylsalicylic acid,351 and the anticonvulsant topiramate (Topamax).352 This clinical situation has a distinctive presentation: affected patients complain of blurred vision at distance, and are noted to have acquired bilateral myopia, with shallow anterior chambers and angle closure.

This condition is thought to be caused by swelling of the lens,243,353,354 although some authorities suggest that forward lens

movement also plays a role. The myopia and induced angle closure disappear a few days after the drug is discontinued. During this time, the patient can be treated with one or more hypotensive drops: -adrenergic antagonist, prostaglandin anaologue, or-adrenergic agonist. A topical carbonic anhydrase inhibitor can also be added (assuming sulfa-based systemic drugs did not precipitate the problem), as can pilocarpine and a hyperosmotic agent if necessary. Cycloplegic agents are thought to be ineffective in this condition.355 Surgical intervention should be avoided, because the lens swelling improves spontaneously.188,355

Although such condition as dislocated and subluxed lenses, from ectopia lentis or microspherophakia, are included in Chapter 16, their clinical diagnosis and treatment are comparable to the clinical management of the senile enlarged lens in phacomorphic PACG.