Abstract
Purpose :
Idiopathic ERM peeling is a challenging surgery because still have unpredictable results. There is no known biomarker to estimate the postoperative visual acuity improvement. The epiretinal membrane (ERM) can cause distortion and disorganization of retinal inner layers (DRIL). The aim of our study is analyze the DRIL thickness as a determinant of visual prognosis in patients operated for ERM.
Methods :
A retrospective cohort study was conducted on patients 40 years or older with symptomatic idiopathic ERM submitted to vitrectomy peeling surgery by one of the authors (LCC or AD), with a minimum follow-up time of 6 months. Patients were excluded if other causes of macular edema, other ocular condition compromising visual acuity, except cataract, damage to the photoreceptor layers, subfoveal atrophy or scarring on OCT were present.
Charts were reviewed for best corrected visual acuity (VA) (preoperative, 3 and 6 months post-op) and OCT measurements: Central foveal subfield thickness (CST); Maximum retinal thickness (MRT); Thickness from internal limiting membrane to the beginning of the outer plexiform layer (DRIL) in the area of maximum retinal thickness; DRIL/maximum retinal thickness ratio. Healthy contralateral eye were used as Control group.
Results :
Seventeen eyes from 17 patients, mean age 66 ± 11 years, were included. Mean baseline VA was 0.8 ± 0.5 logMAR and improved to 0.6 ± 0.7 logMAR after 6 months (p=0.001). After surgery the mean preoperative MRT decrease from 428,00 ± 71,17 μm to 350,70 ± 61,74 μm (p=0.003), the DRIL thickness decease from 273.35 ± 62.97 μm to 180.47 ± 36.10 μm (p<0,001). The preoperative DRIL/MRT ratio decrease from 0.634 ± 0.069 to 0.515 ± 0.063 (p=0.001) after macular peeling. The visual acuity gain was not related with MRT (p=0.25), DRIL thickness (p=0.73) or DRIL/MRT ratio improvements (p=0.59).
Preoperative DRIL/MRT ratio of the control group (fifteen normal contralateral eyes of 15 patients) and study group were statistically significant different (p = 0.001). Six months after surgery, this difference was not statistically significant (p = 0.855).
Conclusions :
Although idiopathic EMR peeling restore MRT, decreasing the DRIL thickness, approaching the control measures, the changes in thickness are not statistically significant related to visual acuity gain, not being possible to use DRIL thickness or DRIL/MRT ratio as a biomarker to predict the visual outcome after surgery.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.