Baseline retinal thickness measurements with a novel integrated imaging system (concurrent optical coherence tomography and fundus photography) positively correlates with spectralis optical coherence tomography.

Abstract

Traditionally fundus photographs and optical coherence tomography (OCT) are obtained separately during evaluation of retinal pathology. We describe a novel integrated imaging system (Monaco, Optos) that records both OCT as well as fundus photography concurrently. The present study aims to measure retinal thickness and compare it to OCT obtained with traditional spectral domain OCT in subjects without known retinal disease to establish normative data for clinical use. In this cross sectional study, fundus photographs and OCT was obtained concurrently in 34 eyes in healthy patients without any known retinal disease with integrated imaging system. OCT with spectralis was also obtained at the same visit for comparison. All subjects underwent a complete ophthalmologic exam to ensure the absence of ocular pathology. OCT was performed by the same operator. Central subfield thickness (CST), central point thickness (CPT), and retinal thickness in nine central subfields were measured with both 1 instruments. Fundus photographs were obtained. Students t-test was used to determine statistical significance. The mean CST as measured with MIIS-SD OCT and Spectralis OCT was 300.53±22.81 µm and 265.18±17.33 µm (P<0.001) respectively. The Pearson's correlation coefficient, r value was 0.5285, P<0.0013. The mean CPT as measured with MIIS-SD OCT and Spectralis OCT was 268.55±20.70 and 230.67±17.75 µm (P<0.001) respectively. The r-value was 0.5697, P<0.0004. The mean difference between retinal thicknesses was 44.88 µm (range, 21-91 µm) in the eight ETDRS subfields, with r value 0.53, P<0.05, ranging from 0.51 to 0.60. Concurrently obtained ultrawide angle fundus photographs revealed (200°) clear media, normal disc, normal vasculature and normal periphery in all patients with excellent resolution. Retinal thickness measurements strongly correlated with those obtained by Spectralis. An increased measurement in thickness of 35.35 µm was noted in the central fovea. In addition, wide-angle fundus photography was successfully obtained in all subjects. Integrated system provides quality fundus photographs as well as OCT, obviates the need for two separate instruments and likely improves the clinic flow.