Abstract
Purpose: :
Optic atrophy constitutes the final stage in the evolution of optic neuropathy. The aim of this study is to demonstrate the utility of Spectral Domain OCT (OCT-SD) in the visualisation of hypo reflective structures (or retinal pseudo cysts) in the internal nuclear layer (INL) in several cases of advanced optic atrophy.
Methods: :
The medical files of 14 patients that presented retinal pseudo cysts during an optic atrophy have been analysed. All patients underwent a complete neuro-ophthalmologic assessment. A retinal nerve fibres (RNFL) analysis of the optic head and of the macula was performed in each patient using the OCT-SD together with a morphological analysis of the macula.
Results: :
In the majority of cases optic atrophy was the result of glaucoma (n=6) or inflammation (n=4). The evolution of these optic neuropathies varied from 1 to 18 years (average: 5,75 years). Visual acuity ranged from 1/20 to 12/10 (average: 5/10). The sex ratio was 0,5 and patients’ average age was 37 years old. The retinal pseudocysts were visualised as hypo reflective lesions in the INL located in the superior (17), nasal (16) and inferior (14) perimacular region. The infrared images revealed a hypo reflective cockade corresponding to the pseudo cysts location in all cases. Fluoresceine angiography (performed in 40% of cases) confirmed the absence of macular oedema. Mean thickness of the peripapillary RNFL was statistically inferior to that of the fellow eye (p=.0003). The RNFL thickness adjacent to the pseudocysts location was statistically inferior to that of the non affected quadrants, while mean retinal thickness was superior in the same area (p=.0046).
Conclusions: :
Retinal pseudocysts can only be visualised with the OCT-SD. It is important to distinguish retinal pseudocysts from cystoid oedema. The adjacent to the pseudocysts retinal thickness has to be analysed in order not to miss a thinning of the overlying retinal nerve fibres. Detecting retinal pseudocysts enables to refine the anatomical follow-up of patients with optic atrophy. Their discovery ameliorates our understanding of the physiopathogenical mechanisms involved in optic neuropathy.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • neuro-ophthalmology: diagnosis • retina: proximal (bipolar, amacrine, and ganglion cells)