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V. Surguch, F. Gora, B. Fassbender, V.–P. Gabel; Assessment of Retinal Function With Fundus–Controlled Microperimetry in Patients Undergoing Macular Laser Coagulation for Diabetic Macular Edema . Invest. Ophthalmol. Vis. Sci. 2005;46(13):395.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Functional results of laser coagulation in patients with diabetic macular edema (DME) are usually assessed with visual acuity only. As macular laser coagulation affects parafoveal retina, microperimetry seems to be suitable approach for assessment of retinal function in patients with DME. Absolute or relative scotoma was previously reported in up to 70% of the patients after laser treatment of DME. The aim of the study was to assess the effect of laser coagulation on macular sensitivity in patients with DME in relation to pre–treatment state and treated area. Methods: Twenty–seven eyes of 20 patients with focal (n=16) or diffuse (n=11) DME where included according to ETDRS criteria and treated with focal or grid laser coagulation, respectively. Follow–up was 3 to 6 months. Microperimetry, fluorescein angiography and optical coherence tomography where performed in all patients before laser coagulation and at follow–up visits. The visual acuity change and change of retinal sensitivity threshold were controlled. To correlate retinal sensitivity with area of treatment, angiography was merged with microperimetry map using special software. Results: Initial mean retinal sensitivity threshold was statistically lower in patients with diffuse DME (9,4 dB vs. 15,8 in focal) and correlated with degree of retinal thickening. Although the variability of retinal sensitivity change was considerable (range: –2,8 dB to +4,7dB) there was no statistically significant change of the threshold either in patients with diffuse or focal DME (mean change: –0,3 dB and –0,2 respectively). Analysis of treated vs. untreated areas after focal treatment demonstrated statistically significant reduction of sensitivity in the area of treatment only in patients with good initial sensitivity (mean change –2,7 dB if initial mean retinal sensitivity threshold was more than 15 dB vs. –0,17 dB if less than 15 dB), whereas retinal sensitivity in untreated areas remained stable in all patients. No absolute scotoma resulting from laser treatment was observed. Conclusions: Fundus–controlled microperimetry may provide additional information on the function of parafoveal retina. After recent laser coagulation in DME it reveals stable retinal sensitivity in most patients. Sensitivity threshold decrease was found only in treated areas with good initial retinal sensitivity. More selective indication of the treatment based on retinal sensitivity may be beneficial.
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