Abstract
Purpose :
A reduction in visual acuity and visual symptoms are considered as indications for epiretinal membrane (ERM) peeling surgery however post-operative functional prognosis is still difficult to predict. Fundus-driven microperimetry provides quantification of retinal sensitivity and is being increasingly used to assess macular function. This study prospectively evaluated anatomical and functional changes using microperimetry undergoing ERM peeling.
Methods :
Thirty patients diagnosed with ERM planned for surgery were recruited. All patients were assessed preoperatively and 3 months post-operatively. Baseline and postoperative examination included best-corrected visual acuity (BCVA), spectral domain optical coherence tomography and microperimetry. Outcome measures were changes in BCVA, central macular thickness (CMT), fixation stability, average and central 4○ threshold. Student's t-test and Pearson's correlation coefficient were used for the statistical analysis.
Results :
At 3 months mean±standard deviation BCVA improved by 6.90±5.48 letters (p<0.01) and CMT reduced by 71.03±50.82µm (p<0.01). There was an improvement in microperimetric average and central 4○ thresholds (4.72±3.89dB and 3.14±6.79dB respectively p=0.01) and fixation stability (13.45±29.81%, p<0.001). Patients with a lower baseline average threshold (<25dB) had a greater mean gain in average threshold and BCVA at 3 months (5.82±3.58dB and 7.09±5.49 letters respectively p <0.01) compared to patients with normal baseline average threshold (3.22±1.48 dB and 6.01±4.3 letters respectively, p=0.01). Baseline BCVA was equivalent between these groups. Improvement in BCVA and reduction in CMT was found to be moderately correlated with an increase in average threshold (R= 0.68, P=0.01 and R= 0.71, P=0.01 respectively). A correlation was not found between BCVA and CMT with central 4○ threshold (R=0.49, R=0.51 respectively).
Conclusions :
Anatomical and functional outcomes improved significantly 3 months post ERM peeling. Despite having similar BCVA at baseline, patients with lower retinal sensitivity compared to those with normal retinal sensitivity at baseline showed greater gain in BCVA and improved macular function after 3 months. Patient selection for surgery and predicting prognosis postoperatively may be guided by baseline microperimetry parameters together with baseline BCVA and symptomatology.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.