The purpose of this study is to correlate changes of visual function three weeks after photocoagulation for macular edema, with changes of center point thickness and macular volume.

Photocoagulation for clinically significant macular edema is effective to reduce the incidence of moderate visual loss. Selective photocoagulation for focal macular edema statistically reduces macular thickening, measured with optical coherence tomography, as early as two weeks after treatment, without significant changes over center point thickness. Although anatomic improvement has been demonstrated with OCT, clinical improvement takes longer to be evident: the Early Treatment Diabetic Retinopathy Study describe that clinical differences in visual function are after the eight month, and all the treatment strategies for macular edema used in this study were associated with an increased rate of moderate visual loss, during the first six weeks. Differences in research can achieve statistical significance, without clinical significance. A study was conducted to identify changes of visual function three weeks after photocoagulation for focal macular edema, and to correlate them with changes of CPT and macular volume, in order to compare the behavior of anatomical changes with visual changes.

Inclusion Criteria:

• type 2 diabetes
• regardless of diabetes duration and retinopathy severity level
• one or both eyes with focal clinically significant macular edema
• treated with selective or focal photocoagulation
• visual capacity under subjective refraction before and three weeks after treatment
• adequate quality 6 mm fast macular map both on the day of photocoagulation, and three weeks after it

Exclusion Criteria:

• patients with myopia over -6.00 diopters
• any retinal disease different from diabetic retinopathy at the moment of photocoagulation
• eyes with a thickened posterior vitreous
• eyes with vitreoretinal traction at the macula
• if they had required scatter photocoagulation before the three weeks evaluation

Target population were type 2 diabetics from Mexico City and its metropolitan area, accessible population were the patients who attended a General Hospital in Mexico City