Faculty Bibliography

BACKGROUND AND OBJECTIVE: To evaluate the effectiveness of combined phacoemulsification and trabeculectomy with mitomycin-C with respect to visual rehabilitation and control of intraocular pressure in patients with coexisting cataract and glaucoma. PATIENTS AND METHODS: The authors retrospectively studied 20 consecutive cases of phacoemulsification with posterior chamber intraocular lens implantation combined with trabeculectomy using mitomycin-C. They included in their study 20 eyes of 19 patients with primary open-angle glaucoma, pseudoexfoliation glaucoma, inflammatory glaucoma, chronic angle-closure glaucoma, and normal tension glaucoma. RESULTS: After a mean postoperative follow-up time of 14.4 +/- 3.1 months, intraocular pressure was reduced from a preoperative mean of 19.2 +/- 6.1 mm Hg to a postoperative mean of 13.4 +/- 3.9 mm Hg (P = .0004). The number of required intraocular pressure-lowering medications dropped from a preoperative mean of 2.3 +/- 0.7 medications to 0.2 +/- 0.4 medications postoperatively (P < .0001), with only 4 eyes requiring the restarting of a single medication each. Mean log(10) (minimum angle of resolution) visual acuity improved from a preoperative 0.66 +/- 0.53 (Snellen 20/91) to a postoperative 0.30 +/- 0.40 (Snellen 20/40) (P<.0005). The most frequent complication was a bleb leak (8 of 20 eyes [40%]), usually occurring early and responding to conservative management. One eye with later-onset bleb leak incurred endophthalmitis. In another eye, hypotony with maculopathy developed. CONCLUSIONS: Phacoemulsification combined with trabeculectomy using mitomycin-C appears to be an effective approach to the management of cataract in patients with glaucoma. It offers potential for good improvement in visual acuity as well as long-term control of intraocular pressure with reduced or no dependence on medications. Potential vision-threatening complications of this procedure, specifically hypotony maculopathy and late-onset bleb leaks, should be considered in the decision to use mitomycin-C.

OBJECTIVES: To demonstrate the inheritance of the pigment dispersion syndrome in 4 families and to determine the location of a gene responsible for this syndrome. PATIENTS: Fifty-four members of 4 families affected by the pigment dispersion syndrome and pigmentary glaucoma. All 4 families are white. Two of the pedigrees are of Irish descent, and 2 are of mixed western European descent that includes some Irish ancestry. INTERVENTIONS: Individuals from 4 pedigrees affected by the pigment dispersion syndrome and their spouses were clinically examined for evidence of the pigment dispersion syndrome. DNA samples from patients and appropriate family members were used for a genome screen using microsatellite repeat markers distributed throughout the human genome. Genotypes were used for linkage analysis to identify markers segregating with the disease trait. RESULTS: Twenty-eight patients showed clinical evidence of the pigment dispersion syndrome. Of these, 14 also had elevated intraocular pressures requiring medical or surgical treatment or both. Significant linkage was observed between the disease phenotype and markers located on the telomere of the long arm of human chromosome 7 (i.e., 7q35-q36). The maximum 2-point lod score (i.e., Zmax) for a single pedigree (i.e., PDS5) was 5.72 at theta = 0 for markers D7S2546 and D7S550. An analysis of affected recombinant individuals demonstrated that the responsible gene is located in a 10-centimorgan interval between markers D7S2462 and D7S2423. CONCLUSIONS: The pigment dispersion syndrome was found to be inherited as an autosomal dominant trait in 4 affected pedigrees. The gene responsible for the syndrome in these 4 families maps to the telomeric end of the long arm of chromosome 7 (i.e., 7q35-q36). Locating a gene responsible for this condition is the first step toward the isolation of the gene itself. Characterization of the responsible gene will help elucidate the pathophysiology of this disease and potentially will lead to new methods of diagnosis and treatment.

OBJECTIVE: Optic nerve head drusen often make evaluation of the nerve head difficult to interpret. In addition, visual field defects are known to occur in patients with optic disk drusen, resembling glaucomatous damage. The authors report two cases of coincident optic nerve head drusen and glaucoma, in which the use of optical coherence tomography (OCT) in evaluating the nerve fiber layer was beneficial. PARTICIPANTS: Two patients with both optic nerve head drusen and glaucoma, one with primary open angle glaucoma, the other with pseudoexfoliation glaucoma were evaluated. Both patients had asymmetric optic disk drusen, with clinically visible drusen only in one eye. INTERVENTION: Ophthalmologic examination, color and red-free photography, automated Humphrey visual field testing and OCT were performed. RESULTS: Nerve fiber layer loss as measured by OCT was found to be greater than expected by the appearance of the optic nerve head and red-free photography, with visual fields consistent with findings in case 1. In case 2, visual fields were full, despite nerve fiber layer thinning seen by OCT and red-free photography. CONCLUSIONS: There can be significant nerve fiber layer thinning in patients with both glaucoma and optic disk drusen, despite the appearance of the optic nerve head in these patients. The cup margin may be obscured by the drusen, giving rise to a falsely full-appearing disk. In such cases, OCT may provide a useful means to quantitatively measure the nerve fiber layer thickness and to aid in the management of these patients by detecting nerve fiber layer thinning earlier than would otherwise be possible.

OBJECTIVE: Brimonidin tartrate is a highly selective alpha 2-agonist. This study investigates the safety and efficacy of 0.2% brimonidine administered twice daily for 1 year in patients with glaucoma or ocular hypertension. METHODS: The study design was a multicenter, double-masked, randomized, parallel-group, active-controlled comparison clinical trial. Subjects instilled 0.2% brimonidine or 0.5% timolol maleate twice daily for 12 months. Subjects were examined at baseline, week 1, and months 1, 2, 3, 6, 9, and 12. A subset of subjects was examined at week 2. RESULTS: Of 443 subjects enrolled in this study, 374 met the entry criteria; 186 received brimonidine and 188 received timolol. Brimonidine-treated subjects showed an overall mean peak reduction in intraocular pressure (IOP) of 6.5 mm Hg; timolol-treated subjects had a mean peak reduction in IOP of 6.1 mm Hg. Brimonidine lowered mean peak IOP significantly more than timolol at week 2 and month 3 (P < .03); no significant difference was observed between the groups for this variable at other visits throughout the 1-year course of the study. No evidence of tachyphylaxis was seen in either group. Allergy was seen in 9% of subjects treated with brimonidine. Dry mouth was more common in the brimonidine-treated group than in the timolol-treated group (33.0% vs 19.4%), but complaints of burning and stinging were more common in the timolol-treated group (41.9%) than in the brimonidine-treated patients (28.1%). Headache, fatigue, and drowsiness were similar in the 2 groups. In general, the tolerance to medication was acceptable. CONCLUSIONS: Brimonidine is safe and effective in lowering IOP in glaucomatous eyes. Brimonidine provides a sustained long-term ocular hypotensive effect, is well tolerated, and has a low rate of allergic response.

The purpose of the study was to evaluate the effect of erbium (Er): yttrium aluminum garnet (YAG) laser trabecular ablation with a sapphire optical fiber on outflow facility. After obtaining baseline outflow facility using a computerized differential pressure perfusion system, human cadaver eyes were subjected to Er: YAG laser trabecular ablation using a sapphire optical fiber. Single pulses at varying energy levels (10 to 20 mJ pulse-1) were applied in a nearly contiguous fashion over four clock hours of meshwork. Post-laser outflow facility was then determined utilizing the same perfusion system and histopathologic analysis performed. Of the ten eyes, nine were perfused to steady baseline facility. One eye was excluded from the study because of a leak in our system during the initial perfusion. The mean baseline facility was 0.283+/-0.08 microl min-1 mmHg-1. There was a significant increase in outflow facility after trabecular ablation, with a mean post-laser facility of 0.62+/-0.15 microl min-1 mmHg-1 (P=0.01). Eyes which received a sham treatment showed no increase or a minimal increase in facility. Histopathologic analysis revealed ablation into Schlemm's canal with some thermal damage to the outer wall at all energy levels. Er: YAG laser trabecular ablation with a sapphire fiber is capable of increasing outflow facility in human cadaver eyes.

BACKGROUND AND OBJECTIVE/OBJECTIVE:Acute and long-term effects of contact transscleral cyclodiathermy (CTCD) were studied in rabbits. MATERIALS AND METHODS/METHODS:In the acute phase, three evenly spaced applications were placed at the limbus in each of four quadrants using the Ophthalmic Diathermy TR4000 (MIRA, Inc., Waltham, MA). Each quadrant of 17 eyes of 13 Dutchbelted rabbits was treated with radio frequencies (RFs) of 1.0 to 4.5, for times of 0.5, 0.75, 1.0 to 3.0, and 4.0 to 10.0 seconds. Eyes were then immediately enucleated and fixed in Karnovsky's solution after the rabbits had been sacrificed with 3 ml of pentobarbital sodium. In the longitudinal phase, four groups of six rabbits each were treated with 20 evenly spaced applications at the limbus at one of four settings: 1.5 RFs/4 seconds, 2.0 RFs/3 seconds, 2.5 RFs/2 seconds, or 3.0 RFs/2 seconds. Intraocular pressures were measured on alternate days for 1 week prior to treatment and for 4 weeks after treatment, following which the eyes were enucleated and fixed in Karnovsky's solution. RESULTS:Gross examination of the acute phase eyes revealed blanching of the ciliary processes at RF settings of 2.5 and higher with exposure times of 1.5 seconds or longer. Gross and light microscopic studies showed that levels of destruction correlated positively with RF settings and exposure times. Higher RF levels resulted in scleral coagulation necrosis on light microscopy. In addition, there was coagulation necrosis of the pigmented and nonpigmented ciliary epithelium and stroma. Longitudinal phase study showed a significant decrease in intraocular pressure (IOP) in the four groups of rabbits treated over the 4-week follow-up period (P = .005, multivariate analysis of variance [MANOVA]). Rabbits treated at higher RF levels sustained a greater IOP-lowering effect (P = .025, MANOVA). Gross and light microscopic examination revealed focal atrophy, fusion, and fibrosis of the ciliary processes. CONCLUSION/CONCLUSIONS:Nonpenetrating CTCD results in focal destruction of the ciliary body in rabbits. The authors found that significant reduction in IOP was possible over the 4-week follow-up period in the Dutch-belted rabbits treated, with greater IOP and tissue effects at higher RF settings.