Quantitative analysis of diabetic macular edema after scatter laser photocoagulation with the scanning retinal thickness analyzer

Retina. 1999;19(1):59-64. doi: 10.1097/00006982-199901000-00010.


Purpose: To define the effect of scatter laser photocoagulation on foveal retinal thickness.

Methods: A commercial scanning retinal thickness analyzer was used to measure retinal thickness. The foveal retinal thickness was measured at the central area of the fundus (0.4 x 0.4 mm). The method was applied to 20 consecutive patients (mean age, 52.4 +/-16.9 years) with diabetic retinopathy. Measurements were performed before and 6 weeks after scatter photocoagulation. Patients were examined by fluorescein angiography and slit-lamp biomicroscopy to detect macular edema.

Results: Mean foveal thickness before scatter photocoagulation was 187+/-45 microm, increasing to 221+/-46 microm after the treatment (P = 0.0001). The foveal thickness increased in 12 eyes (60%). Laser treatment increased macular permeability in two eyes (10%). Biomicroscopic examination revealed central macular thickening in one eye (5%). Visual acuity was reduced in four eyes (20%).

Conclusions: Our results suggest that subclinical macular edema occurs after scatter laser photocoagulation. The retinal thickness analyzer is a sensitive tool for early detection of macular edema after laser treatment, because increases in retinal thickness as small as 34 microm cannot be assessed by slit-lamp biomicroscopy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Capillary Permeability
  • Diabetes Mellitus, Type 2 / complications
  • Diabetic Retinopathy / physiopathology
  • Diabetic Retinopathy / surgery*
  • Diagnostic Techniques, Ophthalmological / instrumentation*
  • Edema / diagnosis*
  • Edema / etiology
  • Edema / physiopathology
  • Fluorescein Angiography
  • Fundus Oculi
  • Humans
  • Laser Coagulation / adverse effects*
  • Macula Lutea / pathology*
  • Macula Lutea / physiopathology
  • Middle Aged
  • Retinal Diseases / diagnosis*
  • Retinal Diseases / etiology
  • Retinal Diseases / physiopathology
  • Retinal Vessels / physiopathology
  • Visual Acuity