Louis B. Cantor

PREVALENCE OF GLAUCOMA: THE BEAVER DAM EYE STUDY

PURPOSE The purpose of this study is to determine the prevalence of glaucoma in the population participating in the Beaver Dam Eye Study (n = 4926). METHODS All subjects were examined according to standard protocols, which included applanation tonometry, examination of the anterior chamber, perimetry, grading of fundus photographs of the optic disc, and a medical history interview. Visual field, cup-to-disc ratio, and intraocular pressure (IOP) criteria were used to define the presence of open-angle glaucoma. Definite open-angle glaucoma was defined by the presence of any two or all three of the following: abnormal visual field, large or asymmetric cup-to-disc ratio, high IOP. RESULTS The overall prevalence of definite open-angle glaucoma was 2.1%. The prevalence increased with age from 0.9% in people 43 to 54 years of age to 4.7% in people 75 years of age or older. There was no significant effect of sex after adjusting for age. Of the 104 cases of definite open-angle glaucoma, 33 had IOPs less than 22 mmHg in the involved eye. Hemorrhage on the optic disc was found in 46 people; 2 of these had glaucoma. Narrow-angle glaucoma was rare, with two definite cases in the population. CONCLUSION The prevalence of open-angle glaucoma in Beaver Dam is similar to that in other white populations. Findings from this study re-emphasize the notion that estimates of glaucoma prevalence should be based on assessing multiple risk indicators.

Morphologic classification of filtering blebs after glaucoma filtration surgery: The Indiana Bleb Appearance Grading Scale

PurposeTo establish a new classification system for filtering blebs according to clinical morphologic parameters. The purpose of this classification system is to provide a uniform and objective assessment of bleb appearance and establish a framework system through which outcomes of filtration surgery may be better correlated to clinical morphology. Materials and MethodsThe Indiana Bleb Appearance Grading Scale contains a set of photographic standards illustrating a range of filtering bleb morphology selected from the slide library of the Glaucoma Service at the Indiana University Department of Ophthalmology. These standards consist of slit lamp images for grading bleb height, extent, vascularity, and leakage with the Seidel test. For grading, the morphologic appearance of the filtration bleb is assessed relative to the standard images for the 4 parameters and scored accordingly. Fifty-one clinical bleb photographs were evaluated and scored by 3 glaucoma subspecialists in a masked fashion according to the scale. ResultsFor all of the grading scales, high interobserver agreement was found using the scale to classify the appearance of filtering blebs (height +0.76; extent +0.78; vascularity +0.90, interclass correlation coefficient for consistency using a 2-way mixed effect model). ConclusionThe Indiana Bleb Appearance Grading Scale is a simple, reproducible, yet comprehensive system for classifying the morphologic slit lamp appearance of filtration blebs.

Retrobulbar arterial hemodynamic effects of betaxolol and timolol in normal-tension glaucoma.

PURPOSE beta-Adrenergic blocking drugs lower intraocular pressure. The question of whether these drugs also alter, either directly or indirectly, orbital hemodynamics is potentially of great importance for patients with normal-tension glaucoma who may have some degree of reversible vasospasm. METHODS We compared the effect of selective (betaxolol) and nonselective (timolol) beta-adrenergic blocking drugs on flow velocities (as determined by color Doppler imaging) in orbital vessels in 13 patients with normal-tension glaucoma (mean age, 62 +/- 3 years; mean intraocular pressure, 15 +/- 2 mm Hg). A one-month drug treatment double-masked crossover design, with a three-week washout before each drug, was used. RESULTS Neither drug changed peak systolic velocity in any of the four vessels studied (ophthalmic, nasal and temporal posterior ciliary, and central retinal arteries). Additionally, timolol did not alter end-diastolic velocity or resistance index (defined as [peak systolic velocity minus end-diastolic velocity] divided by peak systolic velocity) in any of the vessels measured. In contrast, betaxolol tended to increase end-diastolic velocity and to decrease resistance index: the four-vessel average end-diastolic velocity increased 30% (P = .08), and the four-vessel average resistance index decreased significantly (P = .04). These reductions in resistance index occurred despite that betaxolol, in contrast to timolol, did not significantly decrease intraocular pressure. CONCLUSIONS These results suggest that, in patients with normal-tension glaucoma, selective beta-adrenergic blockade (betaxolol) may have ocular vasorelaxant effects independent of any influence on intraocular pressure, whereas nonselective blockade (timolol) lowers intraocular pressure without apparently altering orbital hemodynamics.

Retinal Hemodynamics Using Scanning Laser Ophthalmoscopy and Hemorheology in Chronic Open-angle Glaucoma

PURPOSE Recent studies suggest that elevated intraocular pressure is not the only causative factor for the development of visual field loss and optic nerve damage in glaucomatous eyes. The authors determine whether retinal hemodynamics or blood fluidity are alternated in eyes of patients with open-angle glaucoma compared with those of age- and sex-matched healthy subjects. METHOD High-quality video fluorescein angiograms were obtained from single eyes of 51 patients with chronic open-angle glaucoma. From these angiograms, the arm-retina time, mean dye velocity, and arteriovenous passage time were quantified. The data from patients were compared with those of an age- and sex-matched group of healthy subjects. RESULTS In patients with chronic open-angle glaucoma, an 11% reduction of the mean dye velocity (P < 0.05) and a 41% prolongation of the arteriovenous passage time (P < 0.01) was observed relative to the values obtained among the control subjects. Among hematocrit values, plasma viscosity, and erythrocyte aggregation, only plasma viscosity showed a significant increase (4%; P < 0.01) in patients with chronic open-angle glaucoma. CONCLUSION These results indicate that a pronounced circulatory deficit exists within the retinal vasculature of glaucomatous eyes, which may coexist with, but cannot be fully attributed to, an increase in plasma viscosity.

Reversible Optic Disk Cupping and Visual Field Improvement in Adults With Glaucoma

To assess change over time in the optic disk and the associated change in visual field, we retrospectively reviewed perimetry results and optic disk photographs of adult patients treated for glaucoma. Three glaucoma specialists masked to the clinical course independently reviewed optic disk stereophotographs and visual fields taken before and after treatment. Each member of each pair of stereophotographs or perimetry results, which were presented in a random sequence, were graded as better, worse, or unchanged. Of the 75 eyes, 16 (21%) showed a reversal of optic disk cupping; 20 of the 63 visual fields (31%) were classified as improved. In six of 17 eyes (35%) with a change in the disk (better or worse), a corresponding change was also noted in the visual field. The frequency of improvement in optic disk and visual field appearance was significantly (P less than .05) associated with the degree of intraocular pressure reduction.

Long-term Outcomes of Intraoperative 5-Fluorouracil versus Intraoperative Mitomycin C in Primary Trabeculectomy Surgery

OBJECTIVE To compare the long-term efficacy of intraoperative 5-fluorouracil (5-FU) and mitomycin C (MMC) in primary trabeculectomy. DESIGN Comparative case series and extension of a prospective, randomized controlled trial. PARTICIPANTS One hundred fifteen eyes of 103 subjects undergoing primary trabeculectomy with either intraoperative 5-FU or MMC. METHODS This study is an extension of a 12-month, prospective, double-masked, randomized trial that previously was reported. Subjects were randomized to receive either intraoperative 5-FU (50 mg/ml for 5 minutes) or MMC (0.2 mg/ml for 2 minutes) during primary trabeculectomy. Follow-up data were collected from patient medical records after informed consent was obtained from the study patient. Attempts were made to contact subjects who had been lost to follow-up, and some consented to reexamination. MAIN OUTCOME MEASURES The primary measure was Kaplan-Meier survival function, with failure defined as intraocular pressure (IOP) of more than 21 mmHg or less than 6 mmHg on 2 consecutive visits, less than 20% reduction from baseline IOP, loss of light perception vision, or additional glaucoma surgery to lower IOP (except bleb revision). Secondary measures included IOP, number of glaucoma medications, visual acuity, additional surgeries, and number and type of complications. RESULTS Mean follow up was 53.4+/-31.4 months (interquartile range, 34-82 months) in the 5-FU group and 45.3+/-28.0 months (interquartile range, 19-70 months) in the MMC group (P = 0.15, t test). Kaplan-Meier success was 0.83 at 3 years and 0.76 at 5 years in the 5-FU group and 0.79 at 3 years and 0.66 at 5 years in the MMC group (P = 0.18, log-rank test). Bleb leakage was the most common complication in each group and developed in approximately 4% of subjects in each group per year (P = 0.33, log-rank test). CONCLUSIONS There were no significant differences between topical 5-FU and topical MMC in reducing IOP of eyes undergoing primary trabeculectomy. Both antifibrosis agents may contribute to the development of bleb leakage. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

A prospective randomized trial comparing intraoperative 5-fluorouracil vs mitomycin C in primary trabeculectomy.

PURPOSE To compare the safety and efficacy of intraoperative 5-fluorouracil (5-FU) or Intraoperative mitomycin C (MMC) in eyes undergoing primary trabeculectomy. DESIGN Prospective double-masked randomized clinical trial. METHODS One hundred fifteen eyes of 103 patients with uncontrolled intraocular pressure (IOP) despite maximally tolerated medical therapy or laser were prospectively randomized in a double-masked fashion to one of two treatment groups in a single institution setting. Subjects eyes underwent primary trabeculectomy with either topical 5-FU (50 mg/ml for 5 minutes) or topical MMC (0.2 mg/ml for 2 minutes). Primary outcome measures included the number of eyes achieving target pressures of 21, 18, 15, and 12 mm Hg at 6 and 12 months postoperatively. Secondary outcome measures included IOP, best-corrected visual acuity, complications, and interventions. RESULTS Of the 115 eyes, 57 received 5-FU while 58 received MMC. A target IOP of 21 mm Hg at 6 months was achieved in 53 of 56 (95%) eyes in the 5-FU group and 54 of 57 (95%) eyes in the MMC group (P = 1.00). At 12 months, 45 of 48 (94%) eyes in the 5-FU group met a target IOP of 21 mm Hg while 48 of 54 (89%) eyes in the MMC group did (P =.49). The most common complications in each group were persistent choroidal effusions and bleb leak. CONCLUSION Our study suggests that intraoperative topical 5-FU is at least as effective as intraoperative topical MMC in reducing IOP of eyes undergoing primary trabeculectomy.

A comparative study of betaxolol and dorzolamide effect on ocular circulation in normal-tension glaucoma patients

OBJECTIVE To determine whether dosages of a selective beta-blocking agent (betaxolol) and a topical carbonic anhydrase inhibitor (dorzolamide), sufficient to significantly lower intraocular pressure (IOP), have similar or disparate impact on the retinal and retrobulbar circulation. DESIGN Counterbalanced crossover, with open-label use of medications. PARTICIPANTS Nine persons with normal-tension glaucoma (NTG). INTERVENTION After a 3-week drug washout, NTG patients were studied after 1 month of treatment with either dorzolamide or betaxolol, with determinations of IOP and retinal and retrobulbar hemodynamics. MAIN OUTCOME MEASURES At baseline and after treatment with each drug, retinal arteriovenous passage time was determined by scanning laser ophthalmoscopy after fluorescein dye injection, and flow velocities in the central retinal and ophthalmic arteries were measured with color Doppler ultrasonography imaging. RESULTS Betaxolol and dorzolamide each lowered IOP significantly, with these changes apparent and maximal after 2 weeks (each P < 0.05). In contrast, dorzolamide (but not betaxolol) accelerated arteriovenous passage of fluorescein dye in the inferior temporal quadrant of the retina (P < 0.05). Neither drug affected arteriovenous passage in the superotemporal retina or any aspect of central retinal or ophthalmic artery flow velocity after either 2 or 4 weeks. CONCLUSIONS Although both dorzolamide and betaxolol are effective ocular hypotensive agents and their topical instillation leaves retrobulbar hemodynamics unaltered, dorzolamide alone accelerates inferotemporal retinal dye transit.

The effect of mitomycin C on Molteno implant surgery: a 1-year randomized, masked, prospective study.

PURPOSE The authors assess whether adjunctive mitomycin C improves Molteno tube shunt surgery in terms of intraocular pressure (IOP), visual acuity, and complication rates. PATIENTS AND METHODS Twenty-five eyes of twenty-five consecutive patients undergoing double-plate Molteno implant surgery were randomized to receive either mitomycin C (MMC) 0.4 mg/mL for 2 minutes or a control balanced salt solution in a masked, prospective study. Intraocular pressure, visual acuity, and complications were recorded 1 week and 1, 3, 6, and 12 months after surgery. A repeated measures analysis of variance (ANOVA) model was used to test the overall effect of the drug on IOP and percent change from preoperative IOP. RESULTS Thirteen eyes received balanced salt solution and 12 eyes received MMC. There was no difference between the groups with respect to age, preoperative IOP, log mean angle of resolution (LogMar) visual acuity, or number of preoperative medications. Except for week 1, there were no differences between the groups at any of the clinic visits with respect to IOP and percent change from baseline IOP. Analysis of the visual acuity (LogMar) showed reduction in vision for both groups. Complications were similar in each group, as were number of postoperative hypotensive agents required. CONCLUSIONS Adjunct MMC does not demonstrate a significant difference in outcomes compared with placebo in pressure-ridged Molteno implant surgery. Results of this study are limited by a small number of patients in each group and a fixed dose of MMC.

Hemodynamic and visual function effects of oral nifedipine in patients with normal-tension glaucoma.

PURPOSE To investigate ocular hemodynamic and visual function changes in patients with normal-tension glaucoma after treatment with a calcium channel blocker (nifedipine). METHODS In 21 patients with normal-tension glaucoma, color Doppler imaging of the ophthalmic, central retinal, and short posterior ciliary arteries was carried out after a 4-week washout of prior drug treatment and again after 6 months of treatment with nifedipine (30 mg per day). Visual field sensitivity, spatial contrast sensitivity, and intraocular pressure were also recorded. RESULTS Three subjects experienced intolerable side effects from the drug and were removed from the study. In two other patients, visual function was substantially reduced after 4 months of treatment; nifedipine was discontinued. In the remaining 16 subjects, mean intraocular pressure, retrobulbar hemodynamics, visual field mean sensitivity, and contrast sensitivity at 3, 12, and 18 cycles per degree (cpd), respectively, were unchanged after nifedipine treatment. Contrast sensitivity at 6 cpd, however, improved after drug treatment (P = .004). Individuals with the greatest improvements in contrast sensitivity at 6 cpd showed the largest increases in ophthalmic arterial peak systolic velocity (r = .57; P = .02) and end-diastolic velocity (r = .65; P = .001). CONCLUSION Nifedipine fails to provide uniform visual function or retrobulbar hemodynamic responses in patients with normal-tension glaucoma. Those patients who do show improved visual function also show improved indices of retrobulbar perfusion.