Abstract
Purpose: :
Macular edema is one of the main causes of vision loss in Western populations. Recent advances in macular edema treatments underlined the fact that return to a normal macular thickness does not always mean full vision recovery. The goal of the present study was to document the changes of retinal structures following macular edema.
Methods: :
High resolution optical coherence tomography (OCT) scans were performed in 66 eyes of 62 patients considered to be cured of macular edema after perfused retinal vein occlusion.
Results: :
We have found that loss of integrity of the photoreceptor inner and outer segments (IS/OS) reflectance appeared prior to other structural abnormality. The extent of morphological damage of IS/OS was strongly correlated to visual acuity (VA). Among patients with a normal VA, 6 had modifications of IS/OS line without any other detectable anomaly. Adaptive optics showed loss of the cone reflectance in these areas. On the other hand, eyes showing severe vision loss had pigmentary central migrations, with thinning of the outer nuclear layer. Eye that had vein occlusion associated with periveinular whitening (n= 7) showed thinning of inner nuclear layer, but no detectable damage of photoreceptor outer segments. Alteration of 488nm autofluorescence and damage to inner retinal structure were detected only in the most severely affected cases.
Conclusions: :
We showed that high resolution OCT is a very sensitive tool for identification of neuroglial remodeling after macular edema. Alteration of the outer segment reflectance is an early consequence of macular edema, the extent of which is directly related to VA. Periveinular whitening, on the other hand, electively affects inner nuclear layer.
Keywords: vascular occlusion/vascular occlusive disease • edema • imaging/image analysis: clinical