Laser photomydriasis in pseudophakic pupillary block

The glaucomas in aphakia and pseudophakia

Intraocular pressure may become temporarily or permanently elevated at various intervals following cataract surgery. There are several mechanisms by which glaucoma develops as a complication of the cataract extraction itself. The presence of a pseudophakos may or may not contribute to the pathogenesis. Important diagnostic clues include the anterior chamber depth, the presence or absence of an iridectomy, gonioscopic findings, and the appearance of the optic nerve head. Life-long medical treatment is frequently justified, as alternative laser or surgical modalities may not be successful. The exact causes for high failure of filtration surgery in aphakic eyes is not clearly understood; scarring of the conjunctiva, the vitreous, and altered characteristics of the aqueous humor have all been incriminated. Current research to improve surgical success includes the development of effective artificial drainage implants or the use of pharmacologic modulators of wound healing, which promote filtration by preventing scar formation.

Pseudophakic pupillary block with angle-closure glaucoma in diabetic patients

Six diabetic patients (five women and one man, 63 to 79 years old) developed pseudophakic pupillary block with angle-closure glaucoma two days to one year after undergoing extracapsular cataract extraction. None of the six had had a peripheral iridectomy during the procedure. Symptoms included pain and visual loss. Corneal edema and intraocular pressures as high as 80 mm Hg were also present. Laser iridotomies decreased the intraocular pressure in three cases but failed in a fourth. In one case corneal edema prevented laser treatment but a surgical peripheral iridectomy was successful. One eye with central retinal vein occlusion was treated with panretinal photocoagulation and trabeculectomy.

Neodymium:YAG laser therapy for pseudophakic pupillary block

Pupillary block occurred in six patients with anterior chamber intraocular lens implants. After medical therapy failed, the Nd:YAG laser was used to break the hyaloid face in the pupillary and iridectomy apertures. Iridotomies were also produced at the sites of bulging iris. Following laser treatment the anterior chambers deepened and there were no further signs or symptoms of pupillary block. The Nd:YAG laser proved to be a useful treatment for pseudophakic pupillary block.

Neodymium Q-switched YAG laser lysis of iris lens synechiae

The feasibility of Q-switched Nd: YAG synechiolysis in phakic patients without visible damage to the lens has been demonstrated. The value of this procedure in the management of glaucoma and its advantages over argon laser photomydriasis is discussed.

Clinical experience with the Nd:YAG laser

This study presents the results and complications of 389 patients who were treated with the Nd:YAG laser between September 1982 and November 1983 with at least a six-month follow-up. The majority of patients had a secondary discission of the posterior capsule. Other procedures included vitreolysis, iridotomy, pupilloplasty, synechialysis, intraocular suture cutting, cutting of intraocular lens haptics, and removal of anterior pseudophakic pigmented precipitates. We have purposely avoided performing preoperative laser anterior capsulotomies and have been unsuccessful in reopening freshly sealed trabeculectomy sites. The visual acuity improved in 83.1% of patients. No statistically significant difference in visual outcome was detected in relation to the time interval between surgery and Nd:YAG laser treatment. The most common adverse finding was an increase in intraocular pressure, which occurred to some degree in 63% of patients. Rare complications included cystoid macular edema and retinal detachment. No statistical correlation between these complications and preexisting conditions or intraoperative variables could be found.

Pupillary and iridovitreal block in pseudophakic eyes

Twenty-six cases of pupillary and iridovitreal block in pseudophakic eyes are reported. Although ten patients presented with acute angle closure glaucoma, the majority were asymptomatic and had normal intraocular pressures. While cure was finally achieved in all cases, recurrence of block occurred in six eyes as late as two months after initial successful treatment. A variety of therapeutic modalities including argon laser iridectomy, argon laser gonioplasty (iridoplasty), surgical iridectomy, surgical vitrectomy, Q-switched Nd:YAG laser iridectomy and Nd:YAG laser photodisruption of the anterior vitreous face were needed. Despite successful relief of pupillary and iridovitreal block in these eyes with no evidence of glaucoma prior to cataract and lens implant surgery, four eyes developed eight or more clock hours of peripheral anterior synechiae, and nine eyes continue to require chronic medical therapy for glaucoma.

Pupillary block after intraocular lens implantation

Seventeen patients, ranging in age from 40 to 86 years, developed pupillary block detected one week to three years after intraocular lens implantation. Sixteen of the implants were anterior chamber intraocular lenses and one was a posterior chamber intraocular lens. Despite iris bombé that closed the anterior chamber angle, many cases were asymptomatic and were discovered fortuitously during routine postoperative examinations. Laser iridotomy or iridectomy eliminated the pupillary block in all 17 cases, but permanent synechial closure of a portion of the anterior chamber angle persisted in most cases and sometimes required medication or further surgery. One eye eventually lost all light perception.

Laser iridectomy treatment of acute pseudophakic pupillary block glaucoma

A 71-year-old patient developed acute pupillary block glaucoma two years after uncomplicated extracapsular cataract surgery with primary implantation of a Choyce-style anterior chamber lens. He presented one week after the onset of pain. The attack was relieved with argon laser iridectomy. The presumed mechanism was rotation of the intraocular lens due to blunt trauma, occluding the previously patient single surgical iridectomy site. We felt that in this case, laser iridectomy was a good, safe alternative to surgical iridectomy.

Management of glaucoma in the implanted patient

Implanting an intraocular lens in an eye with controlled open angle glaucoma or angle closure glaucoma does not adversely affect the eye's status. Furthermore, it is extremely rare for primary glaucoma to develop in an eye postimplantation. Secondary glaucoma is certainly more common, although its incidence is not substantially greater than that in nonimplanted eyes. Special considerations with respect to medical therapy and surgical treatment of secondary glaucoma in pseudophakia are discussed.