Dorzolamide-timolol combination and retinal vessel oxygen saturation in patients with glaucoma or ocular hypertension.

AIMS: To examine whether the addition of dorzolamide to timolol monotherapy influences oxygen saturation in the human retina. METHODS: Non-invasive spectrophotometric retinal oximetry was used to measure oxygen saturation in retinal vessels. Twenty patients with open-angle glaucoma (11) and ocular hypertension (9) were recruited. The patients were randomised into receiving timolol monotherapy or dorzolamide-timolol combination for an 8-month test period, followed by a second test period, before which the patients switched treatments. Oximetry measurements were performed at 2-month intervals during each period. Of the 20 patients, 13 followed the study protocol into the second test period, and 10 managed all study visits. RESULTS: The oxygen saturation in retinal vessels was stable within the test periods. The mean arteriolar saturation was 96 (2)% (mean (SD)) during timolol monotherapy and 97 (2)% during dorzolamide-timolol combination therapy (p = 0.17, all patients pooled, n = 13). Corresponding values in venules were 66 (5)% during timolol monotherapy and 65 (6)% during dorzolamide-timolol therapy (p = 0.13). Patients who started on dorzolamide-timolol combination showed a significant reduction in arteriolar (98 (2)% to 95 (2)%, p<0.01) and venular saturation (69 (5)% to 66 (6)%, p<0.05) when changing to timolol monotherapy. CONCLUSION: Adding dorzolamide to timolol monotherapy has a minimal effect, but going from dorzolamide-timolol combination to timolol alone lowered arteriolar and venular oxygen saturation. The retinal oxygen saturation measurements show a high degree of stability over an extended period of time. Previous studies have suggested increased retinal and optic nerve blood flow with dorzolamide. Unchanged oxygen saturation and increased blood flow would indicate increased oxygen delivery to the retina.

Pseudoexfoliation syndrome in Icelandic families.

AIM: To examine the distribution and clinical ophthalmic characteristics of pseudoexfoliation syndrome (pseudoexfoliation) and glaucoma in Icelandic families. METHODS: Icelandic families containing three or more members aged 70 or older with at least one member with pseudoexfoliation were identified. All family members over age 45 were invited to participate. Visual acuity, Goldmann applanation tonometry, gonioscopy, slit lamp examination before and after dilatation, and dilated fundus examination were performed on all available family members. Pertinent data were obtained from medical records, including ophthalmic history and a medical history of cardiovascular disease, cerebrovascular disease, systemic hypertension, and diabetes mellitus. Participants were classified according to affected status for pseudoexfoliation, glaucoma, and age related macular degeneration. RESULTS: Six families were identified who met the criteria for entry into the study. Of 94 family members who were invited to participate 82 were enrolled (87%). Of these 25 (30%) had pseudoexfoliation syndrome, 51 (62%) were unaffected, and six (7%) were suspects. At least one individual with pseudoexfoliation was identified in the second generation of every family. A parent with pseudoexfoliation was identified in all cases either by examination (4/6) or a review of ophthalmic records (2/6). In all cases the mother was the affected parent. The prevalence of glaucoma was significantly greater in the group with pseudoexfoliation (p <0.0001). Although the presence of age related macular degeneration (ARMD) was highly associated with the presence of pseudoexfoliation, the significance was lost after correction for age (p = 0.69). Although the sample size was small, no association between pseudoexfoliation affected status and cardiovascular disease, cerebrovascular disease, systemic hypertension, or diabetes mellitus was found. CONCLUSIONS: Multiple Icelandic families with pseudoexfoliation in two generations were identified. In all cases where determination was possible, transmission to the second generation was through an affected parent. In each case the affected parent was the mother. Pseudoexfoliation was strongly associated with the presence of glaucoma, but was not associated with either ARMD or systemic disease in this study. These data clearly indicate that pseudoexfoliation is a familial condition and although not conclusive, supports the hypothesis that pseudoexfoliation syndrome is genetically inherited.

Visual field results after vitreous surgery in a case series of patients with open-angle glaucoma.

BACKGROUND AND OBJECTIVE: Visual field loss is a complication of vitrectomy and a concern for patients with glaucoma. Our objective was to determine whether vitrectomy is associated with new field defects in patients with glaucoma. PATIENTS AND METHODS: This retrospective case series involved 7 eyes of 7 patients, who had open-angle glaucoma and underwent vitrectomy for macular hole (2) or epiretinal membrane (5). RESULTS: Acuity improved by at least two lines in 5 eyes. Visual fields showed a change in mean deviation following vitrectomy (mean difference -1.50 dB, P=0.0006, paired Student's t-test). One eye had confirmed progression of a pre-existing visual field defect, but no new defects were apparent in the other eyes. Transient intraocular pressure rises requiring therapy occurred in 3 eyes. One eye developed macular edema, but no other operative complications occurred. CONCLUSIONS: The results of our small case series suggest that vitrectomy may be an acceptable intervention in eyes with glaucoma and co-existing macular problems.

Age related macular degeneration in monozygotic twins and their spouses in Iceland.

PURPOSE: To examine the importance of genetic factors in age-related macular degeneration by using a twin study to compare the concordance of age-related macular degeneration in monozygotic twin pairs and their spouses. METHODS: This was a prospective study that included 50 twin pairs and 47 spouses. Zygosity was determined by genetic laboratory testing. Macular findings were graded based on the grading system used by the Macular Photocoagulation Study Group and the International ARM Epidemiological Study Group. RESULTS: The concordance of age-related macular degeneration was 90% in monozygotic twin pairs which significantly exceeded that of twin/spouse pairs (70.2%); p=0.0279. In the nine pairs that were concordant, fundus appearance and visual impairment were similar. Environmental factors and medical history were essentially the same in the twin pairs. CONCLUSION: The statistically significant higher concordance of age-related macular degeneration in monozygotic twins compared to their spouses strongly suggests the importance of genetic factors.

Cystoid macular edema associated with latanoprost therapy in a case series of patients with glaucoma and ocular hypertension.

OBJECTIVE: To identify coexisting ocular diagnoses in a case series of eyes that developed cystoid macular edema (CME) associated with latanoprost therapy. DESIGN: Retrospective observational case series. PARTICIPANTS: Seven eyes of seven patients who developed CME possibly associated with latanoprost treatment were studied. INTERVENTION: When these patients, all of whom were treated with latanoprost in addition to other glaucoma medications, described blurred vision or eye irritation, ocular examination revealed CME, which was confirmed by fluorescein angiography. Latanoprost was discontinued, and in three cases topical corticosteroids and nonsteroidal anti-inflammatory agents were used to treat the CME. MAIN OUTCOME MEASURES: Visual acuity and intraocular pressure were determined before latanoprost use began, during therapy, and after latanoprost use ceased. In these cases, resolution of CME was documented clinically after discontinuing latanoprost. RESULTS: Clinically significant CME developed after 1 to 11 months of latanoprost treatment, with an average decrease of 3 lines in Snellen visual acuity. Intraocular pressure decreased an average of 27.9% during treatment. Cystoid macular edema was confirmed in all cases by fluorescein angiography. In these seven patients, the following coexisting ocular conditions may have placed these eyes at risk for prostaglandin-mediated blood-retinal barrier vascular insufficiency: history of dipivefrin-associated CME, epiretinal membrane, complicated cataract surgery, history of macular edema associated with branch retinal vein occlusion, history of anterior uveitis, and diabetes mellitus. In all cases, the macular edema resolved following discontinuation of latanoprost, in some instances with concomitant use of steroidal and nonsteroidal anti-inflammatory agents. CONCLUSIONS: In this case series of pseudophakic, aphakic, or phakic eyes, the temporal relationships between the use of latanoprost and developing CME, and the resolution of CME following cessation of the drug, suggest an association between latanoprost and CME. In all cases, coexisting ocular conditions associated with an altered blood-retinal barrier were present.

Chronic open-angle glaucoma and associated ophthalmic findings in monozygotic twins and their spouses in Iceland.

PURPOSE: To determine the concordance of glaucoma and ocular parameters in monozygotic twins and their spouses. METHODS: This was a prospective study that included 50 twin pairs 55 years of age or older and 47 of their spouses. Zygosity was determined by genetic laboratory testing. RESULTS: The concordance of open-angle glaucoma in monozygotic twin pairs was 98.0%, which significantly exceeded that of twin/spouse pairs (70.2%). There was a significant association in mean intraocular pressure (IOP), mean axial length, anterior chamber depth, and refractive error in the twin pairs. However, there was no association between the twins and their spouses for these ocular parameters. Eight twin pairs were found to have pseudoexfoliation syndrome (PXFS), five of which were concordant. There was no association between glaucoma and mean axial length or glaucoma and refractive error in the twin pairs studied. CONCLUSION: The statistically significant higher concordance of glaucoma--and the high correlation of mean IOP, mean axial length, anterior chamber depth, and refractive error--in twin pairs and the lack of association of these factors in twin/spouse pairs strongly suggests the importance of genetic factors for these ocular parameters.

Retinal vessel dilatation and elongation precedes diabetic macular oedema.

AIMS/BACKGROUND: Retinal vessel dilatation is a well known phenomenon in diabetes. In this study, the theory of whether excessive changes in diameter and length of retinal vessels occur in the development of diabetic macular oedema was tested, supporting a hypothesis that the development of diabetic macular oedema may be linked to hydrostatic pressure changes described in Starling's law. METHODS: From fundus photographs of diabetic patients attending a regular eye screening programme, the diameter and segment length of retinal vessels were measured in three retinopathy groups (12 patients each) with diabetic macular oedema (DMO), background retinopathy and no retinopathy, over a period of approximately 4 years, ending at the time of diagnosis of diabetic macular oedema in the DMO group. RESULTS: A statistically significant dilatation and elongation of retinal arterioles, venules, and their macular branches was found before the diagnosis of macular oedema in the DMO group. No significant changes were found in the other two groups. CONCLUSION: It is suggested that Starling's law applies to the formation of oedema in the retina as in other tissues.

Physicians' guide to interactions between glaucoma and systemic medications.

PURPOSE: To develop a Physicians' Guide to assist clinicians in the concomitant use of glaucoma and systemic medications. METHODS: The records of 100 consecutive patients with chronic open-angle glaucoma were retrospectively studied to determine the most common systemic medications that are prescribed in this population. The ten most common drug classes were then used to construct a guide to potential interactions and side effects when these medications are used concomitantly with glaucoma drugs. RESULTS: Eighty-four patients were receiving 1 or more medications (a mean of 3.5) for a mean of 2.6 systemic conditions. Systemic antihypertensive agents was the most common class of drugs, being used by 48 patients. Aspirin, the most common single systemic drug, was being used by 25 patients. CONCLUSIONS: A high percentage of patients with chronic open-angle glaucoma receive a wide variety of medications for coexisting systemic disorders. The concomitant use of glaucoma and systemic medications creates the potential for drug interactions, as well as side effects for both groups of drugs, for which the Physicians' Guide may be beneficial.

Retinal vasoconstriction after laser treatment for diabetic macular edema.

The diameter of retinal arterioles, venules, and their macular branches was measured before and after macular laser photocoagulation in one eye each of six men and eight women with diabetic macular edema. The macular arteriolar branches constricted 20.2% (P < .001) and the venular branches constricted 13.8% (P < .001). This autoregulatory vasoconstriction results from the improved retinal oxygenation caused by the laser treatment. By extrapolating the principles of tissue edema formation in general, we hypothesized how macular laser treatment affects diabetic macular edema. Starling's law predicts that (laser-induced) vasoconstriction and reduced intravascular hydrostatic pressure should reduce edema formation in any tissue, including the retina.