Effects of focal/grid laser treatment on the central visual field in diabetic macular oedema: a 2‐year follow‐up study

PURPOSE To assess the long-term effects of focal/grid laser treatment on the central visual field in subjects with clinically significant diabetic macular oedema (CSMO). METHODS Twenty-six subjects with CSMO were included in the study. Fundus photography, assessment of retinal thickness by time-domain optical coherence tomography (OCT), measurement of visual acuity (VA) and standard automated perimetry of the central 10° of the visual field were performed at baseline before focal/grid laser treatment and thereafter at four follow-up visits 6 months apart, when the laser treatment was also repeated in subjects with persistent oedema. Changes in VA and retinal thickness between baseline and study end at 24-month follow-up were calculated. Trends in changes in the visual field were assessed by linear regression of number of significantly depressed test points over time. RESULTS On average after the laser treatment, retinal thickness decreased by 17% and VA decreased by three letters. In most eyes, visual fields were stable over time: the mean of the trend slopes (0.05 points/month) did not differ significantly from 0 (p = 0.63). The number of depressed test points at follow-up was not correlated with either the total number of laser effects or the number of laser sessions. CONCLUSION Focal/grid laser treatment for CSMO did not affect retinal sensitivity in the central visual field in the subjects included in this 2-year follow-up study.