Is there a relationship between outer retinal destruction and choroidal changes in cone dystrophy?

Onder Ayyildiz,Cem Ozgonul,Fatih Mehmet Mutlu,Gokhan Ozge,Ali Hakan Durukan,Tarkan Mumcuoglu,Murat Kucukevcilioglu

doi:10.5935/0004-2749.20160090

Abstract

The aim of the present study was to use enhanced depth imaging optical coherence tomography (EDI-OCT) to investigate choroidal changes in patients with cone dystrophy (CD) and to correlate these findings with clinical and electroretinography (ERG) findings. This case-control study included 40 eyes of 20 patients with CD and 40 eyes of 40 age- and refraction-matched healthy individuals. Choroidal thickness (CT) measurements were obtained under the foveal center and at 500 and 1,500 μm from the nasal and temporal regions to the center of the fovea, respectively. EDI-OCT and ERG data were analyzed, and the correlations of CT with the best-corrected visual acuity (BCVA) and the central foveal thickness (CFT) were evaluated. The mean subfoveal CTs in the CD and control groups were 240.70 ± 70.78 and 356.18 ± 48.55 μm, respectively. The subfoveal CT was significantly thinner in patients with CD than in the controls (p<0.001). The patients with CD also had significantly thinner choroids than the controls at each measurement location relative to the fovea (p<0.001). The subfoveal CT in the CD group correlated with CFT (p=0.012), but no significant correlation was found between the subfoveal CT and BCVA or photopic ERG responses. The present study demonstrated a significant thinning of the choroid in patients with CD. EDI-OCT is a useful technique for describing the choroidal changes occurring in CD. Future studies investigating the association between choroidal changes and outer retinal destruction or the disease stage may provide a better understanding of the pathophysiology of CD.

Highlights

Cone dystrophy (CD) is an inherited retinal disease characterized by the deterioration of the cone cells responsible for central and color vision[1]
Alterations in the retinal structure were pre viously demonstrated in patients with CD using spectral-domain optical coherence tomography (SD-OCT)(3), and some investigators have observed reduced neuroretinal thickness in the fovea centralis and macula using SD-OCT[3]
Data recorded for all subjects included Snellen best-corrected visual acuity (BCVA), intraocular pressure, biomicroscopy, fundoscopy, refractive error, and enhanced depth imaging optical coherence tomography (EDI-OCT) (Spectralis OCT; Heidelberg Engineering, Heidelberg, Germany) findings as well as demographic data such as age and sex

Summary

Introduction

Cone dystrophy (CD) is an inherited retinal disease characterized by the deterioration of the cone cells responsible for central and color vision[1]. A variety of mechanisms, such as defective outer segment morphogenesis, protein transport along the cilium, phototransduction, or cellular interaction, have been suggested as being responsible for cone dysfunction[2]. Alterations in the retinal structure were pre viously demonstrated in patients with CD using spectral-domain optical coherence tomography (SD-OCT)(3), and some investigators have observed reduced neuroretinal thickness in the fovea centralis and macula using SD-OCT[3]. Images acquired with EDI-OCT have an improved ability to visualize the deeper ocular structures and the choroid; they allow the thickness and contour of the choroid to be assessed[5]

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