Medical Care
Medical treatment of phacomorphic glaucoma is aimed at rapidly reducing the IOP to prevent further damage to the optic nerve, to clear the cornea, and to prevent synechiae formation. The reduction of IOP is necessary to prepare the patient for laser iridotomy, which relieves the pupillary block that is causing the glaucoma.
Initial management should address the acute nature of the angle closure and include beta-blockers, alpha 2-adrenergic agonists, and carbonic anhydrase inhibitors. Miotics can worsen the secondary angle closure attack by increasing iridolenticular contact.
Argon laser peripheral iridoplasty (ALPI) has been studied and has been shown to be safe and effective as a first-line treatment of acute phacomorphic glaucoma. [1] This would still need to be followed by cataract extraction for a definitive treatment.
Secondary management begins with laser iridotomy to relieve the pupillary block. This procedure provides an alternate route for aqueous trapped in the posterior chamber to enter the AC, allowing the iris to recede from occluding the trabecular meshwork. Both the argon laser and the Nd:YAG laser can be used. Laser iridectomy sometimes relieves the acute angle-closure attack, but the AC remains shallow. These eyes are susceptible to repeated attacks of angle closure; therefore, cataract extraction should be performed if the AC does not deepen after laser iridectomy.
Gonioscopy is useful after an iridectomy for retrospective assessment of the angle. If the angle is markedly widened, the pupillary block was the likely main mechanism causing the elevated IOP, and laser iridectomy is sufficient in that case. If the angle does not deepen significantly, lens intumescence or forward displacement of the lens is the causative factor, and the patient needs cataract extraction. If the angle closure is not relieved by a laser iridotomy, plateau iris syndrome also is a differential diagnosis.
OCT may serve as an additional aid in establishing a diagnosis prelaser and postlaser. [2]
Surgical Care
Laser iridotomy can temporarily stop an attack of acute pupillary block, but, in most patients with phacomorphic glaucoma, cataract extraction is needed. Laser iridotomy should be performed first as mydriasis before surgery can exacerbate the condition. An extracapsular approach typically is used for cataract extraction. A trabeculectomy often is combined with cataract extraction.
Minimally invasive glaucoma surgeries (MIGS) are effective in lowering the IOP as well, especially in conjunction with cataract surgery. [3]
Studies have shown that a shorter time between duration of symptoms to cataract extraction resulted in greater visual improvement. [4]
Surgery in the nanophthalmic eye is not the procedure of choice; laser peripheral iridectomy and iridoplasty with medical therapy are recommended. The nanophthalmic eye is small with a shallow chamber and moderate-to-high hyperopia. In these patients, cataract extraction has a high rate of exudative detachment of the choroid and ciliary body with rhegmatogenous retinal detachment.
On initial puncture of the capsule on an intumescent lens, an increased risk of a tear extending to the equator exists due to increased pressure forces as the liquefied cortex egresses. One method for dealing with this possibility is using a 30-gauge needle on a syringe to aspirate the liquefied cortex as the capsule is punctured. This provides for a controlled lens decompression.
Because of the increased risk of complications during cataract extraction, deepening of the AC with pars plana vitreous tap or small-gauge vitrectomy has been suggested. [5]
Long-Term Monitoring
Patients should be followed for at least 2 years postoperatively, because 20% of cases may require further glaucoma intervention for IOP control. [4]
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Phacomorphic glaucoma.
