Clinical trials (1, 2) have shown that intensive control of blood glucose and hypertension reduce development of clinically significant macular edema (CSME). Elevated HbA1c (A1C) is a risk for persistent CSME (3). Gross proteinuria is associated with a 95% increase in the incidence of macular edema (4). However, the effect of control of systemic factors before focal laser photocoagulation is not known. We aimed to determine whether multifactorial intervention over 4–6 weeks before focal laser photocoagulation would reduce macular thickness.
In a prospective nonrandomized pilot study, 14 consecutive patients (10 men and 4 women, aged 44–65 years) with type 2 diabetes presenting with nonproliferative diabetic retinopathy and CSME underwent multifactorial interventions including single or multiple modifications in oral hypoglycemic agents (n = 10), atorvastatin (n = 11), antihypertensive drugs (n = 12), and losartan (n = 4) to control A1C, fasting and postprandial blood glucose, systolic and diastolic blood pressure, lipid profile, and 24-h urinary proteins. Detailed ocular examination at recruitment and 6 weeks after interventions included fundus fluorescein angiography and measurement of macular thickness using stratus optical coherence tomography done between 12:00 p.m. and 3:00 p.m. Quantitative data are shown as means ± SD. Intergroup comparison was performed by unpaired t test.
At 6 weeks postintervention, we found a statistically significant decrease in mean A1C (8.3 to 7.62%, P < 0.01), LDL (125.14 to 99.5 mg/dl, P < 0.001), fasting blood glucose (142.07 to 117.5 mg %, P < 0.01), systolic blood pressure (141.43 to 126.43 mmHg, P < 0.002), and diastolic blood pressure (87.14 to 81.54 mmHg, P < 0.001). There was significant decrease in mean retinal thickness in both central 1 mm (244.20 ± 64.30 to 220.30 ± 59.68 μm, P < 0.001) and 6 mm (282.87 ± 51.09 to 261.65 ± 40.08 μm, P < 0.001) of the macula that resulted in a trend toward improvement in visual acuity (logarithm of minimal angle of resolution 0.53 ± 0.29 to 0.52 ± 0.27).
Decreasing macular edema on optical coherence tomography with multifactorial control before laser photocoagulation is encouraging in the management of CSME. Reducing macular thickness facilitates application of a low-energy laser beam. Previously, we found that atorvastatin 6 weeks before focal laser photocoagulation reduced subfoveal migration of lipids in patients with macular edema and dyslipidemia (5). We propose larger studies to determine the role of optimizing systemic factors before laser in CSME.