Nancy A. Remaley

Metabolic Control and Progression of Retinopathy: The Diabetes in Early Pregnancy Study

OBJECTIVE To evaluate the role of metabolic control in the progression of diabetic retinopathy during pregnancy. RESEARCH DESIGN AND METHODS We conducted a prospective cohort study of 155 diabetic women in the Diabetes in Early Pregnancy Study followed from the periconceptional period to 1 month postpartum. Fundus photographs were obtained shortly after conception (95% within 5 weeks of conception) and within 1 month postpartum. Glycosylated hemoglobin was measured weekly during the 1st trimester and monthly thereafter. RESULTS In the 140 patients who did not have proliferative retinopathy at baseline, progression of retinopathy was seen in 10.3, 21.1, 18.8, and 54.8% of patients with no retinopathy, microaneurysms only, mild nonproliferative retinopathy, and moderate-to-severe nonproliferative retinopathy at baseline, respectively. Proliferative retinopathy developed in 6.3% with mild and 29% with moderate-to-severe baseline retinopathy. Elevated glycosylated hemoglobin at baseline and the magnitude of improvement of glucose control through week 14 were associated with a higher risk of progression of retinopathy (adjusted odds ratio for progression in those with glycohe-moglobin ≥ 6 SD above the control mean versus those within 2 SD was 2.7; 95% confidence interval was 1.1-7.2; P = 0.039). CONCLUSIONS The risk for progression of diabetic retinopathy was increased by initial glycosylated hemoglobin elevations as low as 6 SD above the control mean. This increased risk maybe due to suboptimal control itself or to the rapid improvement in metabolic control that occurred in early pregnancy. Excellent metabolic control before conception may be required to avoid this increase in risk. Those with moderate-to-severe retinopathy at conception need more careful ophthalmic monitoring, particularly if their diabetes was suboptimally controlled at conception.

Arteriovenous Crossing Patterns in Branch Retinal Vein Occlusion

PURPOSEnThe study was designed to evaluate the relative anatomic position of the crossing vessels at the site of occlusion in eyes with branch retinal vein occlusion (BRVO).nnnMETHODSnFundus photographs of 106 eyes (104 patients) with recent BRVO from the Eye Disease Case-Control Study were used to examine the relative position of artery and vein at occluded crossings. Three separate comparison groups were formed by identifying corresponding arteriovenous crossings for each occluded crossing in: (1) the ipsilateral but opposite vessel arcade within eyes affected by BRVO; (2) the same quadrant in unaffected eyes of BRVO patients; and (3) the same quadrant in eyes of patients without BRVO, matched by age, sex, and race with the BRVO patients.nnnRESULTSnThe site of obstruction of the branch vein was an arteriovenous crossing in all affected eyes. In 99% of eyes with BRVO, the artery was located anterior to the vein at the obstructed site. In the three comparison groups, the artery was anterior to the vein in 62%, 61%, and 54% of the crossings, respectively, yielding statistically significant differences for each group of control crossings compared with BRVO crossings (P < 0.001).nnnCONCLUSIONnFinding the vein to be consistently between the more rigid artery and the retina at almost all arteriovenous crossings affected by BRVO suggests a possible role for mechanical obstruction in the pathogenesis of BRVO.

Pars Plana Vitrectomy in the Early Treatment Diabetic Retinopathy Study: ETDRS Report Number 17

Background: The Early Treatment Diabetic Retinopathy Study (ETDRS) enrolled 3711 patients with mild-to-severe nonproliferative or early proliferative diabetic retinopathy in both eyes. Patients were randomly assigned to aspirin 650 mg/day or placebo. One eye of each patient was assigned randomly to early photocoagulation and the other to deferral of photocoagulation. Follow-up examinations were scheduled at least every 4 months, and photocoagulation was initiated in eyes assigned to deferral as soon as high-risk proliferative retinopathy was detected. Aspirin was not found to have an effect on retinopathy progression or rates of vitreous hemorrhage. The risk of a combined end point, severe visual loss or vitrectomy, was low in eyes assigned to deferral (6% at 5 years) and was reduced by early photocoagulation (4% at 5 years). Vitrectomy was carried out in 208 patients during the 9 years of the study. This report presents baseline and previtrectomy characteristics and visual outcome in these patients. Methods: Information collected at baseline and during follow-up as part of the ETDRS protocol was supplemented by review of clinic charts for visual acuity and ocular status immediately before vitrectomy. Results: Vitrectomy was performed in 208 (5.6%) of the 3711 patients (243 eyes) enrolled in the ETDRS. The 5-year vitrectomy rates for eyes grouped by their initial photocoagulation assignment were as follows: 2.1 % in the early full scatter photocoagulation group, 2.5% in the early mild scatter group, and 4.0% in the deferral group. The 5-year rates of vitrectomy (in one or both eyes) were 5.4% in patients assigned to aspirin and 5.2% in patients assigned to a placebo. The indications for vitrectomy were either vitreous hemorrhage (53.9%) or retinal detachment with or without vitreous hemorrhage (46.1 %). Before vitrectomy, visual acuity was 5/200 or worse in 66.7% of eyes and better than 20/100 in 6.2%. One year after vitrectomy, the visual acuity was 20/100 or better in 47.6% of eyes, including 24.0% with visual acuity of 20/40 or better. Conclusions: With frequent follow-up examinations and timely scatter (panretinal) photocoagulation, the 5-year cumulative rate of pars plana vitrectomy in ETDRS patients was 5.3%. Aspirin use did not influence the rate of vitrectomy.

ACCOMMODATIVE AMPLITUDES IN THE EARLY TREATMENT DIABETIC RETINOPATHY STUDY: ETDRS Report Number 21

Purpose: Accommodative amplitude in persons with diabetes was investigated using data collected as part of the Early Treatment Diabetic Retinopathy Study. Methods: Accommodative amplitude was measured at the baseline visit in 1,058 patients who had good visual acuity and who were less than 46 years old. Risk factors for low accommodative amplitude at baseline were evaluated using multivariable linear regression. Change in accommodative amplitude after photocoagulation was evaluated using paired t tests and repeated measures analysis of variance for the 578 patients who underwent follow-up measurements at the 4-month visit. Results: Accommodative amplitudes in Early Treatment Diabetic Retinopathy Study patients were lower than normal accommodative amplitudes. Older age (P < 0.001) and increased duration of diabetes (P < 0.01) were risk factors associated with low amplitudes of accommodation in the Early Treatment Diabetic Retinopathy Study. Full scatter photocoagulation was associated with an apparently transient additional reduction in accommodative amplitude; a one third diopter loss in accommodative amplitude was demonstrated only at the 4-month visit (P < 0.001). Conclusion: This study demonstrates that diabetes and duration of diabetes, along with age, are important risk factors for reduced accommodative amplitude. These factors along with an apparently transient decrease in accommodative amplitude following scatter photocoagulation should be considered when assessing the accommodative needs of patients with diabetes and when discussing side effects of full scatter photocoagulation.

Radial keratotomy does not affect intraocular pressure.

BACKGROUNDnRecent reports have suggested that a secondary effect of radial keratotomy may be a reduction in intraocular pressure (IOP) levels.nnnMETHODSnIn an effort to study the relationship of radial keratotomy to IOP, we compared the mean IOP from the baseline and follow-up visits during 1 year after surgery of operated versus nonoperated eyes of patients enrolled in the Prospective Evaluation of Radial Keratotomy (PERK) study. To investigate if radial keratotomy had more of an effect on eyes with higher baseline IOPs, the same analysis was performed on a subset (134 patients) who had a baseline IOP of 15 mm Hg or greater.nnnRESULTSnThe average baseline IOP for both operated eyes and nonoperated eyes was 14.6 mm Hg. There was no significant difference in mean IOP between operated and nonoperated eyes across all time points (p = .18). Although mean IOP changed over time, it did not clinically differ in operated versus nonoperated eyes at any time point. These findings were similar in the analysis of eyes with higher baseline IOP (15 mm Hg or greater).nnnCONCLUSIONnWe conclude that the radial keratotomy performed in the PERK study had no effect on IOP within 1 year after surgery.

Digoxin Does Not Accelerate Progression of Diabetic Retinopathy

OBJECTIVE To test the hypothesis that digoxin, an inhibitor of Na+ -K+ -ATPase activity, accelerates the progression of diabetic retinopathy. RESEARCH DESIGN AND METHODS We compared the incidence and risk of retinopathy in 120 digoxin-taking vs. 867 non-digoxin-taking diabetic participants in the Wisconsin Epidemiologie Study of Diabetic Retinopathy (WESDR) and in 117 digoxin-taking vs. 1,883 non-digoxin-taking diabetic subjects in the Early Treatment Diabetic Retinopathy Study (ETDRS). In both studies, retinopathy was detected by grading stereoscopic color photographs using the modified Airlie House classification scheme, and a two-step difference in baseline retinopathy grade was considered significant. RESULTS After controlling for other risk factors, we found no statistically significant association with either 4-year incidence of retinopathy (WESDR) or progression of retinopathy (WESDR and ETDRS) in patients taking digoxin at baseline compared with those not taking digoxin. CONCLUSIONS These data suggest that digoxin therapy does not adversely affect the course of diabetic retinopathy.