Diabetic macular edema is often associated with multiple comorbid systemic conditions (1). In a pilot study (2), multifactorial interventions in clinically significant macular edema (CSME) led to a decrease in retinal thickness. However, the effect of these interventions, before laser photocoagulation, on the outcome of diabetic macular edema has not been studied.
In a prospective study, 125 patients (180 eyes; 72 men and 53 women; median age 55 years [range 38–72]) completed a minimum follow-up of 1 year (median 1.8 years [range 1.0–2.7]). All underwent multifactorial interventions, including initiation of insulin therapy (n = 47), newer oral hypoglycemic agents (n = 70), angiotensin receptor blockers (n = 59), ACE inhibitors (n = 100), lipid-lowering drugs (n = 107), iron supplements (n = 22), and antihypertensive agents (n = 100), in an attempt to optimize control. Patients were encouraged to meet the targets and maintain them throughout (3). Focal laser photocoagulation was done after 4–6 weeks of initiating control.
Final visual outcomes were compared in the “complete control” (all target values achieved) and the “partial control” (target values not achieved for one or more factors) groups. At baseline, demographic and lipid profiles of two groups were comparable, whereas blood pressure, HbA1c, hemoglobin, and proteinuria were significantly worse in the partial control group.
CSME was bilateral in 55 subjects (110 eyes) and unilateral in 70 (70 eyes). Median interval from diagnosis of diabetes was 10 years (mean 7.2 ± 2.97 years [range 0.5–25.0]) There was statistically significant improvement in best-corrected visual acuity (BCVA) in the complete control group (P < 0.001). The improvement of BCVA by three or more lines was achieved in 25 (29.1%) eyes in the complete control group compared with 20 (21.3%) eyes in the partial control group. The BCVA deteriorated by three or more lines in 14 (14.9%) eyes in the partial control group compared with none in the complete control group.
The ETDRS (Early Treatment Diabetic Retinopathy Study) (4) reported improvement in visual acuity up to one line in 16%, vision remaining unchanged in 77%, and worsening by three lines in 7% of the treated eyes. Improvement of visual acuity by 15 letters (three lines or one-half the initial visual angle) was uncommon (<3%) (5). The ETDRS, however, did not address the issue of systemic control in patients who were candidates for receiving focal laser photocoagulation. In the present series, the complete control group showed three or more lines improvement (one-half the initial visual angle) in 29.1% and stabilization of visual acuity in 70.9%. Even in the partial control group where multifactorial control was attempted, three or more lines of visual acuity improvement was seen in 21.3% of the treated eyes, while the vision remained unchanged in 63.8%. Our study, though limited, has shown better visual outcome than is obtainable by the current standard of care strategies of laser photocoagulation, without enforcing systemic control. In view of our observations, the strategy of multifactorial interventions in CSME before laser photocoagulation needs to be addressed in a larger number of patients.