C. Davis Belcher

Argon Laser Trabeculoplasty in the Presurgical Glaucoma Patient

The trabecular meshwork in 334 eyes of 260 patients with medically uncontrolled primary and secondary open-angle glaucoma was treated with the argon laser. The average intraocular pressure reduction obtained was 7.1 mm Hg. Tonographic data showed significant increase in the facility of outflow. Glaucoma surgical intervention was avoided in 87.5% of phakic eyes and in 62.1% of aphakic eyes. Laser trabeculoplasty was found to be effective in primary open-angle glaucoma, pseudoexfoliation glaucoma, pigmentary glaucoma, angle recession glaucoma, glaucoma secondary to uveitis, and in eyes with failed glaucoma surgical procedures. The length of follow-up in this series ranged from one week to 21 months, with an average of five months. The major complication noted was a rise in intraocular pressure following treatment. In one eye, a small central island of vision was lost due to this intraocular pressure elevation. Treating one-half of the angle in each of two treatment sessions separated by a few weeks reduces the degree of this pressure elevation. The glaucoma status of 3% eyes was made worse after treatment with trabeculoplasty.

Extracapsular Cataract Extraction and Posterior Chamber Intraocular Lens Implantation in Glaucomatous Eyes

Two hundred ninety-six eyes of 250 patients undergoing extracapsular cataract extraction (ECCE) with or without the implantation of a posterior chamber intraocular lens (PC-IOL) were studied. Pre-existing glaucoma of varying severity was present in 139 eyes and no known ocular pathology other than cataract in 157 eyes. During the first eight weeks following surgery, intraocular pressure elevations greater than or equal to 15 mmHg above baseline were seen in 23% of glaucomatous eyes controlled before surgery with glaucoma medications, in 39% of glaucomatous eyes controlled before surgery with argon laser trabeculoplasty, and in only 3% of nonglaucomatous eyes. The implantation of a PC-IOL did not influence the incidence of postoperative intraocular pressure (IOP) elevations. Among glaucomatous eyes with severe preoperative visual field loss (split fixation or central island less than or equal to 10 degrees), 9.7% had worsening of visual field after surgery. Open angle glaucoma of unclear etiology developed in 1.4% of normal eyes following uncomplicated ECCE with PC-IOL implantation. Surgical techniques the authors have found useful in glaucomatous eyes undergoing ECCE with PC-IOL implantation are discussed.

Laser Photodisruptors: Damage Mechanisms, Instrument Design and Safety

Short-pulse neodymium: YAG clinical laser systems permit noninvasive incision of transparent intraocular structures. Selection and safe use of these photodisruptors, however, require a limited understanding of certain basic physical principles. These principles are reviewed and applied in a series of optical experiments designed to study the performance and safety of clinical, short-pulse laser systems. The results of these experiments are presented, in addition to an analysis of current and proposed photodisruptors.

Contact Transscleral Nd:YAG Laser Cyclophotocoagulation: Midterm Results

BACKGROUND Early reports of both contact and noncontact transscleral Nd:YAG laser cyclophotocoagulation have been encouraging; however, recent evidence indicates a significant incidence of hypotony, visual loss, and phthisis with the noncontact technique with more than 6 months of follow-up. The authors sought to determine the intermediate term effects of contact transscleral Nd:YAG laser cyclophotocoagulation (CYC). METHODS The authors followed 116 eyes of 114 patients for a minimum of 1 year after treatment of advanced glaucoma with CYC. RESULTS The mean preoperative intraocular pressure (IOP) of 35.0 +/- 1.0 mmHg decreased to 18.6 +/- 1.1 mmHg (P less than 0.0001) during the average follow-up of 19.0 +/- 0.6 months (range, 12 to 36 months). Intraocular pressure control of 3 to 25 mmHg was achieved in 72%, 3 to 22 mmHg in 65%, and 3 to 19 mmHg in 56% of eyes. Retreatment was required in 31 of the 116 eyes (27%). Intraocular pressure decreased to less than 3 mmHg in 9 eyes and to 0 mmHg in 6 of these 9 eyes. Nineteen eyes, all with initial visual acuity of counting fingers or worse, progressed to no light perception; 17 of 36 eyes (47%) with visual acuity of 20/200 or better lost 2 or more Snellen lines. CONCLUSION Midterm results of CYC continue to be encouraging but are tempered by a nearly 10% incidence of hypotony or phthisis and the progression of visual loss.

Effect of Pilocarpine in Treatment of Intraocular Pressure Elevation Following Neodymium:YAG Laser Posterior Capsulotomy

A prospective study was conducted in 30 eyes of 30 patients to determine if pilocarpine would prevent increased intraocular pressure following Q-switched neodymium (Nd):YAG laser posterior capsulotomy. Fifteen eyes were given pilocarpine 4%, immediately following laser therapy and every hour until bedtime. Fifteen eyes served as untreated controls. Our results show that without prophylactic therapy, 10 of 15 eyes (67%) had a post-laser intraocular pressure (IOP) elevation of greater than 10 mmHg, while only one of 15 (6.6%) of the pilocarpine-treated eyes had a rise of that magnitude. The facility of outflow was reduced by 42% in the untreated eyes in contrast to an increase of 3% in those eyes treated with pilocarpine. Thus, pilocarpine 4% is effective in reducing the incidence and magnitude of elevated IOP following Nd:YAG posterior capsulotomy.

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.

Anterior chamber washout for traumatic hyphema

A surgical approach that involves paracentesis and gentle anterior chamber washout and minimal surgical trauma is presented for dealing with traumatic hyphema. This technique taught by Dr. Paul Chandler produces excellent results and is safe, simple, and without need for elaborate instrumentation.

Acute Glaucoma Following Nd:YAG Laser Membranotomy

A 65-year-old aphake with a functioning filtration bleb underwent neodymium:YAG laser membranotomy. Shortly thereafter, he acutely developed pain, nausea, and visual blur with an intraocular pressure of 42 mm Hg. The mechanism of the acute glaucoma is believed to be occlusion of the fistula by herniated vitreous.

Visual Field Improvement After Neodymium: YAG Laser Puncture of Miotic Cysts

This case report describes the use of a Q-switched neodymium:YAG laser to puncture miotic cysts. Fifteen shots of 0.06 mJ were needed. The pupil dilated more widely following this procedure, resulting in an improvement in the patients visual field. Intraocular pressure (IOP) was not able to be controlled medically, however, and filtering surgery 20 days post laser treatment was required. IOP control had been poor prior to the laser-treatment, and did not appear to be more following treatment.