Standard 6 mm Compared to Wide Field 16.5 mm Optical Coherence Tomography for Staging of Posterior Vitreous Detachment.

Abstract Objective To assess whether 6 mm optical coherence tomography (OCT) scans, which image the macula, can distinguish complete from partial posterior vitreous detachment (PVD) in comparison to 16.5 mm OCT scans, which image the macula, optic nerve, and midperiphery. Design Retrospective cross-sectional study. Subjects We compared 6 mm and 16.5 mm scans in 157 eyes of 157 retina clinic patients (mean age 50 years; range 10–64) with diabetic retinopathy (36%), no retinal disease (19%), and various retinal conditions (55%). We analyzed 16.5 mm scans in 35 normal eyes (asymptomatic fellow eyes of unilateral retinal conditions; mean age 46 years; range 9–63). Methods Each subject was imaged by Heidelberg Spectralis with the standard lens (6 mm scan) and/or the 55-degree lens (16.5 mm scan). On 6 mm scans, we classified eyes as stage 3 partial PVD when the posterior vitreous cortex was visualized without visible attachment. On 16.5 mm scans, we classified eyes as stage 3 when the vitreous was attached at the optic nerve and separated from the macula. On both scan types, we classified eyes as stage 4 when neither the premacular bursa nor the posterior vitreous cortex were visualized. We assessed the accuracy of this system for detecting complete PVD on 6 mm scans by calculating test characteristics using 16.5 mm scans as a reference standard. Main Outcome Measures PVD stage (0–4) Results PVD stage was identical in 6 mm and 16.5 mm scans in 88% of eyes. Compared to 16.5 mm scans, 6 mm scans detected complete PVD (versus earlier stages 0-3) with 95% sensitivity and 98% specificity. Seven eyes were classified as no PVD on 6 mm scans and classified as partial PVD on 16.5 mm scans because vitreoretinal separation was localized to the mid-periphery. All 16.5 mm scans showed some degree of PVD, including scans from 9 subjects between the ages of 9 and 20. Conclusions 6 mm scans distinguished complete from partial PVD with good sensitivity and specificity, but missed the earliest stages of PVD which occur in the mid-periphery. PVD may begin as early as the second decade of life.