Effect of partial posterior vitreous detachment on retinal nerve fiber layer thickness as measured by optical coherence tomography

Objective: To evaluate the effect of partially attached posterior vitreous detachments (pPVDs) at the optic disc on retinal nerve fiber layer (RNFL) thickness as measured by optical coherence tomography. Methods: A retrospective study was conducted using stored Stratus optical coherence tomography III scans of patients with suspected glaucoma from January 2003 to September 2006 at the Montefiore Medical Center, Bronx, New York. All scans were evaluated for vitreous attachments at the disc and were divided into control (without pPVD) and pPVD groups. The RNFL thickness was compared using the fast RNFL protocol. Patients were defined as glaucoma suspects based on clinical findings of either glaucomatous-appearing optic discs or elevated intraocular pressure. All study patients had normal Humphrey visual fields. Results: A total of 110 eyes from 110 patients were included; 59 were in the pPVD group and 51 were controls. Partial PVD was found in 40% of the glaucoma suspects. The mean RNFL thickness of eyes with pPVD was significantly broader than that of controls (101.6μmvs 95.6 μm, respectively; P<.001). The average RNFL thickness of each quadrant was greater in the pPVD group than in the control group, with statistically significant differences in superior and inferior quadrants (P<.001 and P=.001, respectively). Conclusions: More than one-third of this population of glaucoma suspects had a pPVD, indicating that this is a common phenomenon. The results suggest that RNFL thicknesses are greater in patients with pPVD than in controls. This may indicate a limitation of using RNFL thickness as a criterion for evaluating glaucomatous damage in patients with pPVD.