Comparison of macular hole size measured by optical coherence tomography, digital photography, and clinical examination.

AIM: To report on the agreement of macular hole size as measured using optical coherence tomography (OCT), Topcon digital photography, and surgeon estimate on clinical examination. METHODS: Observational cohort series of patients who underwent macular hole surgery over an 18-month period. Patients had OCT scan and digital fundus photographs preoperatively. At operation the surgeon estimated the size of macular hole. The agreement between methods was assessed using the technique described by Bland and Altman. RESULTS: There was good repeatability of photographic and OCT assessment and no evidence of systematic bias between repeated macular hole measurement by digital photography (P=0.36) or by OCT (P=0.58). There was evidence of systematic bias between photographic and surgeon measurements (P<0.001), and between OCT and surgeon (P<0.001) with photographic and OCT assessment being greater. There was also evidence of bias between OCT and photographic measurements with photographic measurement tending to be greater than the OCT measurement for smaller holes and lower for larger holes (P=0.02). CONCLUSIONS: OCT and Topcon digital photography have good repeatability for measurement of macular hole size. Both these methods measured larger hole sizes compared to surgeon estimate. Digital photography and OCT methods did not agree.

Assessment of the reproducibility and repeatability of a method of grading macular subretinal fluid using optical coherence tomography.

AIM: To devise a quantative method for the measurement of the extent of macular subretinal fluid using optical coherence tomography (OCT), and to assess the interobserver and intraobserver agreement for this grading system. METHODS: Observational cohort series. Patients were a cohort who underwent retinal detachment surgery over an 18-month period. All patients had OCT scan at 6 weeks after surgery. The scans were graded by two independent observers experienced in OCT interpretation and each grader was masked to the others findings. Observer 1 then regraded the scans on a later day masked to his previous findings. The interobserver and intraobserver agreement was assessed using weighted Kappa (Kw) statistics. RESULTS: In all, 116 patients were analysed. Both the intraobserver and interobserver agreement was very high, with Kw being 0.9631 and 0.9070, respectively. CONCLUSIONS: The grading system for assessment of the extent of macular subretinal fluid using OCT appears to have very good reproducibility and repeatability. We propose that this grading system would be clinically useful when applied to pathologies visible on OCT scan of the macula.