Evaluation of post-operative foveal location and microstructural changes after pars plana vitrectomy for rhegmatogenous retinal detachment using enhanced-depth imaging optical coherence tomography.

Background: Patients who had successful rhegmatogenous retinal detachment (RRD) surgery often complained of metamorphopsia due to postoperative fovea displacement and alteration of the foveal microstructure. The papillo-foveal distance (PFD) is correlated bilaterally. Therefore, PFD from the fellow healthy eye could be used to determine the change of foveal position in eyes with successful RRD repair. Ultra-high-resolution optical coherence tomography (UHR-OCT) could explain incomplete visual recovery by demonstrating foveal misalignment and changes in foveal microstructure. The rationale of the study is to assess the changes in the foveal location and microstructural layers after successful retinal reattachment and correlate them with visual dysfunction.

Patients and methods: A prospective interventional cross-sectional controlled study included patients who had successful retinal reattachment and complained of defective vision or metamorphopsia. The primary outcome measure is to evaluate the post-operative foveal location. The secondary outcome measures are the assessment of metamorphopsia, the evaluation of the foveal microstructural changes, and the correlation between foveal shift, metamorphopsia, foveal microstructure, and visual function. We used a standard Amsler chart to detect subjective metamorphopsia and a modified Amsler chart to quantify metamorphopsia. We used the enhanced-depth imaging optical coherence tomography (EDI-OCT) to detect changes in PFD and the foveal microstructure. p < 0.05.

Results: The study included 50 study eyes and 50 control eyes. The male gender constituted 70%. The mean age was 53 years. The mean baseline BCVA was 0.001. The incidence of foveal displacement was 70%. Disorganized retinal inner layers (DRIL) occurred in 56% of eyes, and disorganized retinal outer layers (DROL) occurred in 72% of eyes. The mean postoperative BCVA was 0.3. The subjective metamorphopsia was mild in 39%, moderate in 24%, severe in 33%, and very severe in 3% of eyes. The mean quantitative metamorphopsia was 587 mm. PVR correlated significantly with the foveal shift. DROL correlated significantly with subjective metamorphopsia. There was a statistically significant difference between subjective metamorphopsia and quantitative metamorphopsia.

Conclusion: Foveal displacement and metamorphopsia after successful retinal reattachment pose significant morbidity. UHR-OCT is pivotal in evaluating the anatomical outcome after successful retinal re-attachment surgery and its relation to visual function.