Abstract
Abstract: :
Purpose: Different examination methods exist in the evaluation and follow–up of patients with diabetic macular edema. Optical coherence tomography (OCT) enables a quantitative measurement of retinal thickening, while fundus–controlled perimetry has been proven useful in the assessment of macular function. Aim of this prospective study was to compare the value of optical coherence tomography, as an objective and noninvasive tool, with microperimetry, as a subjective method of retinal function testing, in the follow–up of patients with diabetic macular edema. Methods: This study enrolled 19 eyes of 19 consecutive patients (mean age 65±7 years) with clinically significant macular edema (CSME) before laser photocoagulation. Mean visual acuity (VA) was 20/40 at baseline visit and all patients were followed over a period of at least 6 months with 4 to 6 follow–up visits after photocoagulation. Retinal thickness was measured using the Stratus OCT (Carl Zeiss Inc.), while retinal sensitivity was determined employing the MP1 Micro Perimeter (Nidek Inc.) Retinal thickness was assessed from 6 OCT scans centered on the fovea. Differential light sensitivity was determined in a 16 degrees field with 53 locations using a 4–2–1 staircase strategy. Results: Mean retinal thickness in the 3 mm diameter circle around the fovea did not change significantly (315±63 µm at baseline to 320±50 µm after 6 month). Neither did retinal function show any significant change (11.4±4.9 dB at baseline visit and 11.8±4.3 dB at 6 month). Although subjective visual function slightly improved during the first two follow–up visits, mean VA remained constant at 20/40. Only mean differential light threshold showed significant correlation to VA. Conclusions: Both techniques showed to be useful in the evaluation and follow–up of diabetic macular edema. Although no significant change of subjective and objective clinical parameters during follow–up of CSME after laser treatment could be observed, retinal thickening could be documented using OCT as well as central functional deterioration could be confirmed with fundus perimetry. Microperimetry enabled a more precise analysis of retinal function than isolated VA testing. Both techniques allow for effective evaluation of therapeutic strategies in patients suffering from diabetic retinopathy in addition to the standard clinical examination.
Keywords: diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry