Focal choroidal excavation’s coexistence with other choroidal diseases impairs vision

By Lucy Piper, Senior medwireNews Reporter

Focal choroidal excavation (FCE) appears to be relatively common and can have a detrimental effect on vision, a study of Korean patients suggests.

This effect was largely attributable to coexisting macular choroidal diseases, say the study researchers, led by Christopher Seungkyu Lee (Yonsei University College of Medicine, Seoul, South Korea). And, although classically thought to be a congenital malformation, acquired forms of the condition, resulting from scarring changes in the choroidal layer, do exist.

The findings, published in Ophthalmology, shed light on the causes and clinical implications of FCE, which the researchers say have been “largely unknown” until now.

Spectral-domain optical coherence tomography identified FCE in 41 eyes of 38 individuals, from two tertiary medical centres in Korea. When considered in conjunction with published research, this case series in Asian patients, aged an average of 50 years, suggests there might be a predisposition to FCE among Asian individuals, says the team, adding that further validation of this is needed.

Most of the patients were moderately myopic and had a mean refractive error of –3.7 dioptres. The mean subfoveal choroidal thickness of FCE eyes was 284 µm, which did not differ significantly from that of 41 individuals matched for age, gender and refractive error, and is therefore unlikely to be a characteristic of the condition.

But the researchers note that mean choroidal thickness under the evacuation was reduced in 22 eyes with hyperreflective choroidal tissue, at 128 versus 190 µm in those without hyperreflective choroidal tissue.

In all, 12 (29%) FCEs were of the nonconforming type of excavation, where there is a separation between the photoreceptor tips and the retinal pigment epithelium, and these were significantly associated with visual symptoms, largely due to co-occurring with central serous chorioretinopathy (CSC).

Indeed, visual symptoms in 19 of the 23 symptomatic eyes were attributed to concurrent macular pathology; CSC in 10 eyes and choroidal neovascularisation (CNV) in nine eyes, including one with polypoidal choroidal vasculopathy (PCV) features.

The remaining four symptomatic eyes had excavation in the foveal area, three of which were of the nonconforming type.

The researchers note that there were two instances where FCE occurred as a secondary ocular change. In one case, a small choroidal excavation developed during CNV scarring over 45 months of follow-up, while in another case concurrent with PCV, the excavated area enlarged slightly over 52 months of follow-up.

“It may be the case that FCE can develop as a congenital lesion or an acquired lesion”, say the researchers. “These 2 FCE types would not necessarily represent the same disease entity or share the same pathogenesis.”

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