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.

The UK Prospective Diabetes Study Group: Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).
The UK Prospective Diabetes Study Group: Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38.
Do DV, Shah SM, Sung JU: Persistent diabetic macular edema is associated with elevated hemoglobin A1C.
Am J Ophthalmol
Klein R, Klein BEK, Moss SE, Cruickshanks KJ: The Wisconsin Epidemiological Study of Diabetic Retinopathy XVII: the 14-year incidence and progression of diabetic retinopathy and associated risk factors in type 1 diabetes.
Gupta A, Gupta V, Thapar S, Bhansali A: Lipid-lowering drug atorvastatin as an adjunct in the management of diabetic macular edema.
Am J Ophthalmol