Abstract
Purpose:
To investigate incidence, time course and pathophysiology of visual loss in eyes with macula-on rhegmatogenous retinal detachment operated with vitrectomy and silicone oil tamponade.
Methods:
15 eyes of 15 patients, who had been operated with 5000 centistoke silicone oil between 2006 and 2014 were included in a retrospective case series. Examinations included logMAR best corrected visual acuity (BCVA), visual field testing, spectral domain optical coherence tomography (OCT), electro retinogramme (ERG), and fluorescein angiography (FLA). All patients gave full written informed consent to data acquisition and processing according to the declaration of Helsiniki.
Results:
Visual loss was seen in 8 (53 %) eyes of 15 patients with symptomatic central scotoma which was confirmed by visual field testing (5/6). Preoperative median BCVA of these patients was 0.15 (0.5 to 0), prior to oil removal 0.7 (1.0 to 0.5), 6 weeks post oil removal 1.0 (1.5 to 0.2). BCVA recovered in 5 patients to median 0.15 (0.5 to 0.1) at latest follow up. BCVA remained 1.0 in 3 patients. Visual loss occurred within the first 6 postoperative weeks in 4 patients, all of which recovered. OCT revealed significant thinning of the foveal and parafoveal ganglion cell and inner plexiform layers in affected eyes (mean 58.3 µm encircling fovea, 500 µm radius) compared to their healthy partner eyes (mean 84.5 µm encircling fovea, 500 µm radius, p= 0.01, n= 6). Intraretinal microcysts in the inner plexiform and inner nuclear layers were present in 5/6 eyes. In 2 patients with visual loss multifocal ERG showed a reduction in electrophysiological activity of central stimulation areas, which improved over time without increase in visual acuity. FLA was normal in all cases.
Conclusions:
The frequency of visual loss under silicone oil appears to be underestimated. We see visual loss with recovery after oil removal in 1/3 and persisting visual loss in 1/5 of all patients. The point in time of oil removal has no effect on the visual outcome. An early drop in vision seems to be of good prognosis. Thinning of inner retinal layers accompanied by intraretinal microcysts possibly filled with silicone oil might be a pathophysiological explanation for visual loss in these patients. Multifocal ERG improvement over time supports the hypothesis. However, there is a need for further prospective multicenter studies to confirm our results.