history:A 29-year-old man presented with symptoms of blurred vision and micropsia for three months in the left eye. He had no history of previous ocular problems. He was generally well and not on any regular medication.
The patient was emmetropic with acuities of 6/6 (20/20) in the right eye and
6/9 (20/30) in the left eye. He was N5 (Jaeger 1) in both eyes and had full
color vision on Ishihara plate testing. The anterior segments were normal in
both eyes. On fundoscopic examination, the right eye was normal, and the left
eye had a large diameter optic disc with a coloboma, an inferior retinochoroidal
coloboma, central retinal pigment epithelial atrophy and macular retinal
elevation (Figure 1).
Ocular coherence tomography (OCT) of the left eye
revealed schisis-like separation of the retinal layers in the macula with a
partial outer layer detachment adjacent to the disc and strands of tissue
bridging the schisis cavity
(Figure 2). A connection between the inner layer
separation and the optic disc was suggested. Mean central 1 mm retinal thickness
was 697 microns. Visual acuity deteriorated 2 months after presentation to 6/18
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Color fundus photograph of the left eye
showing the colobomatous disc (black arrow), retino-choroidal coloboma (red
arrow), foveal retinal pigment epithelial atrophy and macular elevation (blue
Linear horizontal OCT image pre-treatment
through the disc. The scan shows schisis-like separation of the retinal layers
in the macula with a partial outer layer detachment adjacent to the disc
Central serous retinopathy (CSR)
In CSR there is a localized serous detachment of the neurosensory retina in the region of the macula secondary to focal RPE defects. There is no optic disc pit seen as in this case. In CSR, fluorescein angiography can show a ‘smoke-stack’ appearance, which was not seen in this case either. The lack of these findings excludes this as the diagnosis.
Retinal pigment epithelial detachment (PED)
PED is probably caused by reduction of the hydraulic conductivity of the thickened Bruch’s membrane, thus impeding movement of fluid from the RPE towards the choroid. OCT images show separation of the RPE from Bruch’s membrane by the fluid in PED. There is no sub-RPE fluid in this case, and the clinical appearance excludes this as the diagnosis.
Age related macular degeneration (AMD)
AMD usually affects patients over the age of 50 years and is the most common cause of irreversible visual loss in the developed world. Clinical features include the presence of drusen, pigment epithelial alterations, hemorrhages, choroidal neovascularization and RPE detachment. In view of the age of this patient (29 years) and the lack of other AMD clinical features, this is not the diagnosis.