Comparison of smartphone ophthalmoscopy with slit-lamp biomicroscopy for grading vertical cup-to-disc ratio

Purpose of the Study: The purpose of the study was to determine the agreement between smartphone ophthalmoscopy and slit-lamp indirect biomicroscopy when assessing vertical cup-to-disc ratios (VCDRs). Materials and Methods: This was a clinical-based, prospective, comparative instrument study performed in 110 patients with ocular hypertension (OH) or primary open angle glaucoma (POAG). Patients underwent estimation of VCDR by undilated smartphone ophthalmoscopy and slit-lamp biomicroscopy by 2 masked glaucoma specialists. Results: The differences between the mean VCDR estimations obtained by each techniques were not statistically significant. Overall exact agreement between the 2 modalities was found in 21 of 29 eyes (72.4%; simple k=0.63, confidence interval, 0.52-0.73, P<0.001) in POAG patients and in 52 of 78 eyes (66.7%) in OH patients. The optic nerve head was not gradable with smartphone ophthalmoscopy in 1 eye with POAG and in 2 eyes with OH because of media opacities and/or small pupil diameter. Conclusions: Smartphone ophthalmoscopy showed substantial agreement with slit-lamp examination for the estimation of the VCDR. The ubiquitous diffusion of the smartphones, together with their connectivity and portability features, enables an extensive benefit for this technology to be used in glaucoma screening, especially in low-resource settings.