Session Title: Imaging II
Session Date/Time: Friday 12/09/2014 | 16:30-18:00
Paper Time: 17:42
Venue: Boulevard C
First Author: : A.Abdullatif EGYPT
Co Author(s): : H. Mortada M. Abdelhakim H. El Said
The purpose of this study was to study the structure-function relationship following primary vitrectomy for rhegmatogenous retinal detachment by correlating findings on spectral domain optical coherence tomography and visual acuity.
This is a prospective interventional non-randomized case series at Kasr Al-Ainy teaching hospital, Cairo University. Seventy eyes, of 70 patients, with rhegmatogenous retinal detachment (RRD) and proliferative vitreoretinopathy of intermediate severity (PVR
Patients underwent primary vitrectomy, with or without phacoemulsification and intraocular lens (IOL) implantation. One-time cross-sectional analysis of the retinal structure at 4 weeks postoperatively was chosen. The presence or absence of vitreoretinal interface abnormalities, intra-retinal fluid and subretinal fluid (SRF), were evaluated. Also the status of the inner segment/outer segment (IS/OS) junction and external limiting membrane (ELM) were judged in the images as disrupted or complete. In the scan that showed the largest defect, the extent of disruption was measured along a 1.8 mm-diameter area centered on the fovea. The extent of disruption in the IS/OS line and ELM were graded according to their length into four grades similar to that done by Otani et al (2010) in diabetic macular edema; grade 0 (intact), grade 1 (mild disruption, i.e. <400 micron), grade 2 (moderate disruption, i.e. ≥400 microns but <1400 micron) and grade 3 (severe disruption, i.e. ≥1400 micron, or completely lost). The correlations between SD-OCT findings and postoperative best-corrected visual acuity (BCVA) were analyzed.
All patients achieved complete postoperative reattachment with 95% SOSR and mean logMAR BCVA one month following the surgery of 0.79± 0.35. The values of BCVA showed statistically significant difference between patients with ERM and those without (p=0.017). There was statistically significant correlation between both the length of IS/OS and ELM defect and the visual acuity (r= 0.782, p< 0.001 for IS/OS, r 0.650, p=0.02 for ELM). The values of BCVA showed statistical significant difference between the four classified grades (p= 0.009 for IS/OS and p=0.011 for the ELM). Our study showed statistically significant correlation between length of IS/OS defect and the duration of retinal detachment (r= 0.602, p= 0.05).
Primary vitrectomy achieves high primary anatomical success rates. SD-OCT is a valuable, noninvasive tool for evaluating foveal microstructural changes. Incomplete visual acuity recovery after anatomically and clinically successful repair has been attributed to several factors: subretinal fluid, epiretrinal membranes and interruption of either IS/OS line or ELM. The extent of IS/OS and ELM disruption could be a measure of the structural and functional health of the photoreceptors and can explain poor visual outcome in successful retinal detachment surgery with an otherwise normal foveal contour.