Photoreceptor Inner and Outer Segment Junction Reflectivity after Vitrectomy for Macula-Off Rhegmatogenous Retinal Detachment

Abstract

Purpose. To evaluate the spatial distribution of photoreceptor inner and outer segment junction (IS/OS) reflectivity changes after successful vitrectomy for macula-off retinal detachment (PPV-mOFF) using spectral domain optical coherence tomography (SdOCT). Methods. Twenty eyes after successful PPV-mOFF were included in the study. During a mean follow-up period of 15.3 months, SdOCT was performed four times. To evaluate the IS/OS reflectivity a four-grade scale was used. Results. At the first follow-up visit the IS/OS had very similar reflectivity in entire length of the central scan with total average value of 1,05. At the second visit the most significant increase of the reflectivity was observed in temporal and nasal parafovea with average values of 2,17 and 2,22, respectively. The third region of increased reflectivity of an average value of 2,33 appeared during the third follow-up visit and was located in the foveola. At the last follow-up visit in entire central cross section the IS/OS reflectivity exceeded grade 2 reaching the highest average values in nasal and temporal parafovea and foveola. Conclusions. A gradual increase of the IS/OS reflectivity was observed in eyes after PPV-mOFF. The process is not random and starts independently in the peripheral and central part of the macula which may be attributed to the variable regenerative potential of cones and rods.

Figure 1

Restoration of normal IS/OS reflectivity after pars plana vitrectomy for macula-off rhegmatogenous retinal detachment in central SdOCT cross section. (a) Two weeks after surgery the IS/OS line is invisible in central part of the scan and has reduced reflectivity in periphery. (b) 10 weeks after surgery the IS/OS can be recognized in the entire scan and has reflectivity similar to normal one in foveola (thin arrows) and parafovea (thick arrows). (c) 44 weeks after surgery the IS/OS reflectivity increased in the area between foveola and parafovea (arrows). (d) 80 weeks after surgery only focal IS/OS disruptions can be observed (arrows).

Figure 2

Asymmetrical increase of the IS/OS reflectivity after pars plana vitrectomy in central SdOCT cross section. (a) 4 weeks after surgery two areas of increased IS/OS reflectivity can be found in the foveola and parafovea (arrows). (b) 72 weeks after surgery area of normal IS/OS reflectivity appeared in foveola, parafovea, and nasal part of the fovea (arrows).

Figure 3

En face reflectivity maps at the level of the IS/OS layer. Maps were calculated for an area of 6 × 6 mm. The bright blue color depicts regions of normal IS/OS reflectivity. The dark blue color indicates areas of reduced IS/OS reflectivity. (a) Patient 1. Map calculated 9 months after surgery. Areas of normal reflectivity are visible in the peripheral part of the macula (thick arrow). A small, bright island is also visible in the center of the fovea (thin arrow). (b) Patient 1. 16 months after surgery. Areas of normal reflectivity have enlarged significantly. The superior macula and the central area of normal IS/OS have merged. (c) Patient 2. Seven months after surgery. An area of normal IS/OS is visible in the peripheral part of the macula (bright blue). (d) Patient 2. 14 months after surgery. A new area of normal reflectivity has appeared in the central fovea (arrow).