Retinal shortening: Ultrasonic evaluation of proliferative vitreoretinopathy

PURPOSE: To evaluate the effect of extraretinal proliferative vitreoretinopathy (PVR) on retinal shortening in eyes with rhegmatogenous retinal detachment (RD) using ultrasound (USG) and objectively prove the presence of intraretinal PVR (iPVR). METHODS: This is a double-masked pilot prospective controlled case series. Patients with total RD planned for vitreoretinal surgery were included in the study. USG was used to determine retinal-to-choroidal length ratios (RCRs) in all the quadrants. Group 1 included 10 patients with preoperative PVR more than Grade B while Group 2 had 14 with PVR of Grades A or B. Severe retinal shortening was defined as RCR < 0.8. Primary outcome measures were severe retinal shortening and an early unexplained recurrence of RD within 15 days of surgery. RESULTS: Mean RCRs were significantly low in all the four quadrants of Group 1 upon comparison with Group 2. The mean RCR had a good negative correlation with number of quadrants of PVR (R = −0.66, P ≤ 0.001). Overall, severe quadrantic retinal shortening was detected in nine patients. In these 9 patients, 11 of the 36 retinal quadrants had severe retinal shortening in the absence of extraretinal PVR (ePVR). Six patients developed early unexplained RD, and all of these belonged to Group 1. Severe quadrantic retinal shortening had the highest odds ratio of developing early unexplained RD (odds ratio = 58, P = 0.01). CONCLUSION: Retinal shortening occurs both due to ePVR and iPVR, and iPVR occurs independently at least in some cases. Severe quadrantic retinal shortening indicates poor primary anatomical prognoses.