Vascular effects on ciliary tissue from endoscopic versus trans-scleral cyclophotocoagulation.

AIM: To determine the acute and chronic vascular effects of endoscopic cyclophotocoagulation (ECP) versus trans-scleral cyclophotocoagulation (TCP) in a rabbit model. METHODS: 20 rabbits underwent ECP in one eye and another 20 rabbits had unilateral TCP. Five treated eyes from each group underwent endoscopic fluorescein angiography (EFA) of the treated ciliary processes at each of the following time points: immediate, 1 day, 1 week, and 1 month. Five untreated rabbits were used as controls. The NIH Image software program was used to trace ciliary processes in order to determine their mean intensity, as a measure of their perfusion. Histopathology was also performed on eyes from each time point. RESULTS: Immediately and 1 day after laser, both TCP and ECP eyes demonstrated severely reduced or non-existent blood flow in the areas of treatment. TCP treated processes essentially remained non-perfused at the 1 week and 1 month time points. ECP treated processes showed some reperfusion at 1 week and greater reperfusion by 1 month. Histopathology confirmed the overall greater vascular occlusion seen with TCP. CONCLUSIONS: Chronic poor perfusion of the ciliary body after TCP may account, in part, for its efficacy, as well as the significant complications including hypotony and phthisis. Late reperfusion of this region after ECP may provide some insight into the differences in efficacy and complication rates compared to TCP.

Long-term effects of mitomycin on filtering blebs. Lack of fibrovascular proliferative response following severe inflammation.

BACKGROUND AND OBJECTIVE: The use of antimetabolites, such as fluorouracil and mitomycin, enhances the success rate of filtering surgery, especially in eyes at high risk for failure, and increases the likelihood of a thin, avascular filtering bleb. In addition, mitomycin may cause long-term inhibition of the fibroblast's ability to proliferate in the conjunctiva and Tenon's capsule. Preoperative and postoperative inflammation frequently contributes to scarring of filtering blebs. The purpose of this study is to evaluate the effect of intraoperative mitomycin use on the survival of filtering blebs after severe inflammation. DESIGN: We retrospectively studied three eyes that had undergone trabeculectomy with intraoperative mitomycin. Two eyes had concomitant intraocular lens implantation. All three eyes had blebs that functioned well postoperatively. PATIENTS: These eyes sustained episodes of intense inflammation in the form of herpes zoster ophthalmicus, endophthalmitis, or purulent infection of the bleb postoperatively. RESULTS: Following treatment of the inflammation, no change in the appearance or function of the bleb could be detected. CONCLUSION: Either the indirect effect of mitomycin in producing a thin, avascular bleb or a long-term effect of mitomycin on the ability of conjunctival and Tenon's capsule fibroblasts to proliferate may have contributed to bleb survival.

Arden contrast sensitivity testing in glaucoma.

Two hundred sixteen eyes (164 patients) were studied with the Arden printed contrast gratings to test Arden's hypothesis that an abnormal score would distinguish between eyes with and without glaucoma. Ninety-five eyes were normal and 75 eyes were glaucomatous; 46 eyes suspected of being glaucomatous were also studied to determine whether such eyes would score differently than eyes with normal intraocular pressures. No age-dependent trend in scoring was found in the different diagnostic categories, except with the age group younger than 40 years, which had consistently better contrast sensitivity. The tests were demonstrated to be reproducible over time and showed little or no intertester variability. Decreased contrast sensitivity was found in the glaucomatous eyes compared with normal eyes. The scores of the eyes suspected of being glaucomatous fell between the scores of the glaucomatous and normal eyes. Overlapping distributions among the three groups, however, limit the diagnostic value of the test.

Screening for glaucoma with frequency-doubling technology and Damato campimetry.

OBJECTIVE: To assess frequency-doubling technology (FDT) perimetry (Humphrey Systems, San Leandro, Calif) and Damato campimetry (Precision Vision, Villa Park, Ill) for detecting glaucoma in a public glaucoma screening. METHODS: A 2-day public glaucoma screening was held at 2 different institutions. Each subject underwent 2 visual field screening tests (Damato campimetry and FDT perimetry in screening mode), an ophthalmologic examination, and Humphrey perimetry (24-2 FASTPAC) for each eye. Eyes were divided into 4 categories: normal, ocular hypertensive, glaucoma suspect, and definite glaucoma. The sensitivity and specificity of FDT perimetry and Damato campimetry for detecting glaucoma were estimated with receiver operating characteristic curves. RESULTS: Among 240 subjects who underwent FDT, the number identified as normal, ocular hypertensive, glaucoma suspect, and definite glaucoma was 151, 28, 35, and 26, respectively; among 175 subjects who underwent Damato campimetry, the numbers for the same groups were 118, 19, 19, and 19, respectively. The areas under the receiver operating characteristic curve for FDT perimetry and Damato campimetry were 0.925 and 0.883, respectively. The optimal sensitivity and specificity for FDT perimetry were 92% and 93%, while those for Damato campimetry were 53% and 90%, respectively. The average test time was 1 minute and 3 minutes per eye for FDT perimetry and Damato campimetry, respectively. CONCLUSION: Frequency-doubling technology perimetry was superior to Damato campimetry in this screening for glaucoma.

Brimonidine in the prevention of intraocular pressure elevation following argon laser trabeculoplasty.

OBJECTIVE: To evaluate the efficacy of 0.5% brimonidine tartrate, an alpha 2-adrenergic agonist, in preventing intraocular pressure (IOP) elevation following argon laser trabeculoplasty. DESIGN: In a multicenter, double-masked, randomized study, 248 patients (248 eyes) who underwent argon laser trabeculoplasty were allocated to four treatment groups: (1) brimonidine administered before and after the procedure; (2) brimonidine administered before the procedure; (3) brimonidine administered after the procedure; and (4) a vehicle administered before and after the procedure. RESULTS: In the first 3 hours after argon laser trabeculoplasty, only one (0.54%) of the 183 brimonidine-treated patients had a postlaser IOP increase of 10 mm Hg or more, while increases of this magnitude occurred in 13 (23%) of the 56 patients who received only the vehicle (P < .001). The three brimonidine-treatment groups demonstrated significant mean reductions in IOP from the pretrabeculoplasty level (-4 to -8 mm Hg), whereas the vehicle-treated group showed an increase in mean IOP (4 mm Hg). Side effects associated with brimonidine treatment included conjunctival blanching (40.9%), lid retraction (7.6%), and a slight lowering of the systolic blood pressure. CONCLUSIONS: One drop of 0.5% brimonidine administered either before or after surgery was found to be efficacious and safe in preventing posttrabeculoplasty elevations in IOP.

Psychophysical changes in glaucoma.

Chronic glaucoma has been thought to spare the central vision until quite late in the disease process. This assumption is based on the use of the relatively insensitive Snellen chart to measure central vision and the relatively sensitive kinetic and static perimetry to measure the peripheral vision. In recent years, new measures of visual function have been utilized to assess patients with glaucomatous damage. Sensitive methods of measuring central visual function such as color vision, contrast sensitivity (both spatial and temporal), and macular light sensitivity have demonstrated defects early in the glaucomatous process - sometimes even before perimetry is affected. Since these visual functions are largely mediated by macular fibers, central vision may be affected earlier and more frequently in glaucoma than previously believed. Studies of both the nerve fiber layer of the retina and of quantitative light sense perimetry suggest that glaucomatous damage may occur diffusely across the population of nerve fibers, focally in the arcuate portion of the nerve fiber layer, or in both places. Color vision, contrast sensitivity and macular light sense appear to correlate with the diffuse type of nerve fiber layer damage. The exact utility of the psychophysical tests that assess central visual function for the clinical management of glaucoma has not yet been demonstrated. More work is needed to determine which tests are most useful, what parameters are most efficient, and what the diagnostic and prognostic significance of abnormal values may be. However, the studies of color vision, contrast sensitivity and macular light sensitivity have led to a better understanding of how glaucoma affects visual function.

Needle revision with and without 5-fluorouracil for the treatment of failed filtering blebs.

Twelve patients with failed or failing filtering blebs were treated by transconjunctival needle revision of the bleb. Seven of these received 5-fluorouracil as an adjunct. Intraocular pressure decreased from 31.3 +/- 8.8 mm Hg (range, 20 to 47 mm Hg) to 17.0 +/- 3.7 mm Hg (range, 8 to 22 mm Hg). The length of follow-up ranged from two to 31 months. The results in 11 of 12 patients (91.6%) were satisfactory, defined by an intraocular pressure of 22 mm Hg or less, with or without antiglaucoma medications, and requiring no subsequent procedures for control of intraocular pressure. The success rates and overall pressure lowering effect of the seven patients receiving and the five patients not receiving 5-fluorouracil were similar. However, most patients receiving 5-fluorouracil were thought to be at higher risk for surgical failure. Complications of needle revision were minor and resolved without sequelae. We advocate the consideration of transconjunctival needle revision with or without the use of 5-fluorouracil as a useful therapeutic modality in the management of the failed or failing filtering bleb.

Hypotonous maculopathy after trabeculectomy with subconjunctival 5-fluorouracil.

Long-term success in trabeculectomy has been enhanced in recent years by postoperative subconjunctival 5-fluorouracil injections and intraoperative mitomycin C applications. During 1990 and 1991, after trabeculectomy with a small scleral flap (2 x 3 mm) augmented by antimetabolite therapy, hypotonous maculopathy developed in eight eyes of six patients. The maculopathy was characterized by loss in visual acuity, retinal striae, and choroidal folds without evidence of vascular leakage. The average loss in visual acuity was four Snellen lines. Visual acuity did not return to preoperative levels even when the hypotony could be reversed. Reversing the hypotony with various strategies aimed at stimulating subconjunctival scarring has been relatively ineffective. During that same period, an additional seven eyes in six patients had prolonged hypotony but without development of maculopathy. Features common to patients who developed maculopathy included age (mean age, 46 years; range, 32 to 60 years) and myopia (mean, -7.5 diopters; range, -0.75 to -11.75 diopters). The patients with hypotony but no maculopathy were older (mean age, 73 years; range, 63 to 82 years) and were closer to emmetropia (mean, -1.11 diopters; range, +1.50 to -9.00 diopters). The means of the ages and refractive errors were statistically significantly different in the two groups (P = .007 and .04, respectively). Trabeculectomy with adjunctive antifibrosis therapy should be used with caution in young myopic patients.

Presumed activation of herpetic keratouveitis after Argon laser peripheral iridotomy.

PURPOSE: To describe presumed activation of herpetic keratouveitis after argon laser peripheral iridotomy. METHOD: Case report. RESULTS: A 68-year-old man developed chronic, unilateral, anterior uveitis associated with decreased corneal sensation, focal keratitis, and increased intraocular pressure after argon laser peripheral iridotomy. Treatment with oral acyclovir and discontinuation of topical latanoprost resulted in prompt and continued control of both the intraocular inflammation and pressure. CONCLUSION: Herpetic keratouveitis may occur after argon laser iridotomy, and it should be considered when postoperative inflammation persists despite appropriate use of topical corticosteroids, particularly in patients with a history of herpetic eye disease.

Late onset of sequential multifocal bleb leaks after glaucoma filtration surgery with 5-fluorouracil and mitomycin C.

PURPOSE: To describe the late onset of sequential multifocal bleb leaks as a postoperative complication after filtering surgery with antimetabolites. MATERIALS: Retrospectively, 385 consecutive eyes (304 patients) undergoing trabeculectomy with 5-flurouracil (5-FU) or mitomycin C (MMC) from 1989 to 1994 were reviewed. Eyes with filtration bleb leak occurring 6 months or more after trabeculectomy were analyzed, and clinical characteristics of the filtration bleb, response to treatment, and bleb histopathology from eyes undergoing bleb excision were analyzed. RESULTS: In seven (1.8%) of 385 consecutive eyes from 304 patients undergoing glaucoma filtration surgery with 5-FU or MMC, repetitive bleb leaks in different locations of the bleb were observed from 9 to 44 months (mean, 20.4 months) after the procedure. One hundred ninety-three eyes (50%) were treated with 5-FU and the remaining eyes, with MMC. All eyes had transparent, avascular, lobular, cystic blebs. Bleb leaks occurred in five eyes treated postoperatively with subconjunctival 5-FU and in two eyes in which MMC was used intraoperatively. Three eyes (all treated with 5-FU) required surgical excision, and four eyes healed with soft contact lens, cyanoacrylate glue, or intrableb injection of autologous blood. Histopathology of the bleb leak sites demonstrated focal epithelial thinning and interruption with subjacent hypocellularity and stromal collagen degeneration. CONCLUSION: Late sequential multifocal bleb leaks may occur after glaucoma filtration surgery with administration of antimetabolites (5-FU or MMC) and are associated with epithelial break-down, hypocellularity, and stromal collagen necrosis in the filtration bleb.

Intraocular pressure and corneal curvature changes on application of limbal-scleral suction fixation ring in rabbits.

Suction rings are used to stabilize the globe during refractive surgery procedures. This study investigates the changes in ocular pressure and corneal curvature induced by a suction ring on rabbit corneas. A sharp rise in intraocular pressure, to as high as 80 mm Hg, followed by a time-dependent decline was found. The application of this ring also caused astigmatic changes in the cornea. Corneal thickening was also encountered. These findings have implications for possible artifactual changes during photorefractive keratoplasty and raise the possibility of intraocular pressure-induced damage in susceptible individuals.

The temporal visuogram in ocular hypertension and its progression to glaucoma.

In a study of progression to glaucoma in ocular hypertensive eyes followed for at least 4 years, temporal flicker sensitivity measured at the beginning of the period was evaluated as a predictor of the likelihood of progression. Significantly abnormal temporal visuograms at a 1 criterion predicted progression in 9 of 10 eyes that developed glaucomatous losses. Temporal visuograms for locations in the nasal arcuate area (15 nasal to fixation) showed much greater sensitivity to visual loss than those in the central part of the retina. Comparison with threshold perimetry losses showed that patients within the normal range on the central four points were also within normal range on the temporal visuogram. Peripheral flicker testing was more sensitive than threshold perimetry to losses in the nasal arcuate area in glaucoma patients.

Midterm follow-up results of combined phacoemulsification, lens implantation, and mitomycin-C trabeculectomy procedure.

PURPOSE: This study evaluates the visual, refractive, perimetric, and intraocular pressure (IOP) results following combined phacoemulsification, lens implantation, and trabeculectomy with mitomycin-C. METHODS: Twenty-nine consecutive eyes of 26 patients with cataract and glaucoma that had undergone combined phacoemulsification, posterior chamber lens implantation, and limbus-based trabeculectomy with mitomycin-C applied after the cataract removal and trabeculectomy had a minimal follow-up time of 12 months (mean follow-up 20 +/- 6.3 months). Each eye was evaluated for visual acuity, corneal astigmatism, IOP, bleb persistence, optic nerve stability, visual field status, and complications. Goldmann visual fields were assessed by a semi-quantitative method and threshold static perimetry by statistical indices of diffuse damage (mean deviation) and focal loss (corrected pattern standard deviation). The preoperative and postoperative results were compared by Student's t-test. RESULTS: All eyes that were free of pre-existing macular disease demonstrated significant improvement in visual acuity by at least 4.5 lines of Snellen acuity. Postoperative astigmatism was negligible (0.29 diopters). The average IOP reduction was 6.5 mm Hg, with the one year or more average of 13.4 mm Hg on virtually no antiglaucoma medicines (0.2 +/- 0.5). Functioning filtering blebs persisted in 86% of eyes. Of 11 patients tested with pre- and postoperative Goldmann perimetry, only two showed visual field defect progression despite IOPs < 15 mm Hg. Of the 12 eyes with pre- and postoperative static threshold perimetry, the mean deviation deteriorated in nine eyes (p = 0.003). The corrected pattern standard deviation changes were not statistically significant (p = 0.69). Complications (including two cases of late-onset endophthalmitis) were comparable with other studies reporting filtration surgery with adjunctive antimetabolites. We detected no untoward effects of applying the mitomycin at the end of the procedure rather than at the beginning. CONCLUSIONS: The combined procedure technique that we describe appears to be effective at restoring visual acuity and significantly reducing IOP. Nevertheless, many visual fields showed continued, diffuse glaucomatous progression in the year or two following surgery and the development of late endophthalmitis in two eyes is a concern.

Evaluation of optic disc measurements with the glaucoma-scope.

PURPOSE: We evaluated the Glaucoma-Scope's ability to acquire images of the optic disc, the reproducibility of its analysis, and the comparison between it and expert evaluation. METHODS: One hundred and sixty-eight patients with satisfactory standard fundus photography were referred for Glaucoma-Scope analysis. Characteristics of eyes in which Glaucoma-Scope analysis could not be obtained were evaluated. Eight glaucoma patients (15 eyes) were quantitatively evaluated: inter- and intraobserver reproducibility of the Glaucoma-Scope analyses were calculated utilizing weighted Kappa index of agreement and coefficient of variation. The Glaucoma-Scope cup-to-disc ratio was calculated from the gray scale analysis and compared to the ratio as evaluated by a glaucoma expert. RESULTS: Glaucoma-Scope analysis was not achieved in 14% of a total of 336 eyes of 168 patients. The conditions associated with the inability to obtain a satisfactory image were hyperpigmented fundi, pseudophakia, aphakia, corneal opacities, cataract, and contact lenses. The quantitative analysis of the 15 patients showed small inter- and intraobserver means of the coefficient of variation (0.136 +/- 0.023 and 0.129 +/- 0.016) and SD (0.063 +/- 0.0056 and 0.064 +/- 0.0077) and moderate-substantial intra- and interobserver agreement (weighted K = 0.427 +/- 0.1 and 0.61 +/- 0.14, respectively). Significant disagreement (weighted K = -0.11, p = 0.0023) was found between Glaucoma-Scope (mean 0.52 +/- 0.064) and expert's evaluations (0.673) of the cup-to-disc ratio. CONCLUSIONS: The inter- and intraobserver reliability and low variation of the Glaucoma-Scope readings indicates moderate to substantial reproducibility for detecting changes in optic disc's topography under selected conditions. However, eyes with moderate cataract, aphakia, pseudophakia, mild corneal opacity, darkly pigmented fundi or myopia were inconsistently analyzable. In a small group of randomly selected eyes there was very low agreement between the glaucoma expert's evaluation of the optic disc and that of the Glaucoma-Scope. These findings raise questions about the usefulness of the instrument as a diagnostic tool for glaucoma but show promise for detecting change when good images are possible.

Interobserver and intraobserver variability in the detection of glaucomatous progression of the optic disc.

PURPOSE: To evaluate the potential value of obtaining follow-up stereoscopic photographs on glaucoma suspects in identifying progressive optic nerve damage. METHODS: Nineteen sets of stereoscopic optic disc photographs, reflecting one eye from each of 19 patients at two time points, were selected from the records of subjects enrolled in the Glaucoma Screening Study. By consensus, three experts judged 13 of these eyes to have progressive glaucomatous optic nerve damage. Four other ophthalmologists who were masked to the expert panel evaluation then assessed glaucomatous progression in the same eyes. They were asked to evaluate glaucomatous progression in three ways: first, by drawing the optic nerve head appearance from initial stereoscopic photographs and later comparing their own drawings to follow-up stereoscopic photographs; second, by comparing serial stereoscopic photographs directly; and third, by comparing drawings of the optic nerve head made by another examiner to the follow-up photographs. RESULTS: Neither sensitivity nor specificity was consistently better for serial stereoscopic photographs than for drawings. Individual ophthalmologist agreement rates with the expert panel's determinations of progression were 23-62% when examiners compared their own drawings to follow-up photographs, 54-71% when examiners compared serial stereoscopic photographs, and 38-85% when comparing another ophthalmologist's drawings to follow-up photographs. CONCLUSION: Baseline stereoscopic photographs of the optic nerve head did not substantially improve recognition of progressive glaucomatous optic nerve damage when compared with the use of baseline drawings of the optic nerve head made from photographs in subjects who developed visual loss in the interim.

Glaucoma screening using the scanning laser polarimeter.

PURPOSE: To determine the ability of scanning laser polarimetry (GDx Nerve Fiber Analyzer; Laser Diagnostic Technologies, Inc., San Diego, CA) to separate normal eyes and those considered likely to have glaucoma in a public glaucoma screening. METHODS: A 2-day public glaucoma screening program was held at two different institutions. Each subject underwent ophthalmologic examination, Humphrey perimetry (24-2 Fastpac program), and imaging using scanning laser polarimetry (GDx) in each eye for allocation into a diagnostic category: normal, ocular hypertensive, glaucoma suspect, or glaucoma. Results from the normal and glaucoma groups were analyzed, using modulation parameters calculated from a measurement band located 1.8 disc diameters from the disc, and selected parameters provided automatically by GDx software. Receiver operating characteristic curves were used to depict the sensitivity/specificity relationship at different GDx parameter cutoff levels. RESULTS: Of 200 subjects, 197 were classified; 122 were classified as normal, 23 were classified with ocular hypertension, 30 were classified as glaucoma suspects, and 22 were classified with definite glaucoma. Three subjects had ocular diseases other than glaucoma. The maximum area under the receiver operating characteristic curve for modulation parameters was 0.935, and for the GDx software parameters was 0.901. CONCLUSIONS: Scanning laser polarimetry may be useful in glaucoma screening.

The effect of glaucoma on central visual function.

Glaucoma has traditionally been thought to affect peripheral visual function in its early stages and to spare central visual function until late in the disease process. The basis for this assumption has been the reliance on Goldmann-type perimetry, a rather sensitive method for assessing the peripheral visual function, and on Snellen-type visual acuity measurements, a rather insensitive method of assessing central visual function. This belief has persisted despite frequent complaints from patients with glaucoma that their central vision is disturbed. Over the past two decades, several investigations of central visual functions and their anatomic substrate have challenged this assumption. Histologic studies of the nerve fiber layer in eyes with glaucoma suggest that the number of ganglion cells subserving macular function is decreased even in early stages of the disease. In addition, afferent pupillary defects (a gross measurement of macular nerve fiber function) may also be present in eyes with early glaucoma. Several studies have demonstrated that color perception (largely mediated by the fovea) is defective in glaucoma. Furthermore, defects in color perception may even precede the development of visual field abnormalities. Seventy-eight percent of patients with early glaucomatous visual field defects were found to have a defect in color perception when tested with a desaturated D-15 color panel that tests only the central 1.5 degrees. In addition, both chromatic and achromatic foveal perception channels are defective in eyes with glaucoma and even in some eyes of those with suspected glaucoma. Contrast sensitivity has become recognized as an important component of visual function. Partial loss of contrast sensitivity may cause a degradation in the quality of perception even though the Snellen visual acuity remains normal. Although contrast sensitivity is not entirely a macular function, it has been shown that as little as 3 degrees of disturbance of the macula (eg, with macular degeneration or with an artificial central scotoma) will reduce the contrast sensitivity, suggesting that this modality is indeed mediated to a significant extent by this portion of the retina. Spatial contrast sensitivity appears to be reduced in patients with glaucoma. However, because of overlap and lack of a sharp cutoff measurement, present testing procedures fail to allow a clear distinction between the glaucomatous and normal populations. Although reduced temporal contrast sensitivity has been demonstrated in glaucomatous eyes by others, I undertook a systematic investigation of this function in a large group of patients with glaucoma and with suspected glaucoma.(ABSTRACT TRUNCATED AT 400 WORDS)

The corneal endothelium and Descemet's membrane in the iridocorneal endothelial syndrome.

A 39-year-old woman with progressive left unilateral glaucoma associated with corneal edema, iris changes, and peripheral anterior synechia formation underwent a left trabeculectomy and iridectomy in an attempt to control the intraocular pressure. Shortly after surgery the edema worsened despite low intraocular pressure measurements. A repeat trabeculectomy combined with a full thickness keratoplasty was performed 11/2 years later. The posterior corneal surface was found to be covered by a partially doubled layer of endothelial cells with ultrastructural features resembling epithelium. Similar cells were not noted on the surface of the initial trabecular meshwork and iris specimens, but were seen on the surface of the specimens obtained at the second trabeculectomy. The anterior and middle portions of Descemet's membrane, formed during perinatal and early adult life, appeared normal, but its posterior portion appeared abnormal. The ultrastructural changes in the endothelial cells and the abnormalities observed in Descemet's membrane suggest that the endothelial cells were initially normal but subsequently acquired epithelial-like features as they degenerated and proliferated. The continued presence of corneal edema despite the hypercellularity of the endothelium suggests that the proliferating cells were permeable to aqueous.