Abstract
Abstract: :
Purpose: Diabetic maculopathy is the leading cause of diabetic blindness. Imaging such as optical coherence tomography – 3 (Carl Zeiss Stratus OCT–3) is useful in diagnosing diabetic macular oedema. It can also be used to monitor macular oedema and its response to focal or grid laser treatment. Two macular scanning programs (fast and standard) are available with the OCT – 3 machine. We have compared these two scanning programs to evaluate the accuracy of macula thickness measurement in 3 groups of diabetic patients. The time required to perform each macula scan using the two programs was also investigated. Methods: 79 eyes of 40 patients were prospectively recruited from the diabetic eye clinic and grouped into the following : i) diabetic retinopathy with no clinically significant macular oedema (CSMO) ii) diabetics with CSMO ( treated or untreated) iii) diabetics with ischaemic maculae and no CSMO Each patient underwent a timed macula scan using OCT –3 fast and standard programs for each eye. Macula thickness measurements through the fovea were recorded for each program. Fixation was graded for each eye. Results: Bland & Altman plots indicate that there was a very good agreement in the measurement of retinal thickness for the two programs (fast and standard) in all diabetic groups. An analysis of variance with random effects for subject showed agreement, resulting in an intraclass correlation coefficient of 0.97 (95% ci 0.95 to 0.98). A paired t–test shows that, on average, the time taken for the standard program is significantly greater. The mean time difference was 55 seconds (95% c.i. 46 to 64; P=0.0001). Conclusions: We have demonstrated that the fast macula program is sufficient in producing quick and accurate foveal thickness measurements compared to the standard program in all our groups of diabetic patients. We conclude that the OCT fast macula program can be safely used when aiding diagnosis of diabetic macula oedema and its monitoring following laser treatment.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • diabetic retinopathy