Original article
Choroidal Thickness in Normal Eyes Measured Using Cirrus HD Optical Coherence Tomography

https://doi.org/10.1016/j.ajo.2010.04.018Get rights and content

Purpose

To examine choroidal thickness and area in healthy eyes using spectral-domain optical coherence tomography (SD-OCT).

Design

Retrospective, observational case series.

Methods

Thirty-four eyes (34 subjects), with no retinal or choroidal disease, underwent high-definition raster scanning using SD-OCT with frame enhancement software. Choroidal thickness was measured from the posterior edge of the retinal pigment epithelium to the choroid/sclera junction at 500-μm intervals up to 2500 μm temporal and nasal to the fovea. The central 1-mm area of the choroid was also measured, along with foveal thickness of the retina. All measurements were performed by 2 independent observers. Statistical analysis was used to correlate inter-observer findings, choroidal thickness and area measurements with age, and choroidal thickness with retinal foveal thickness.

Results

The 34 subjects had a mean age of 51.1 years. Reliable measurements of choroidal thickness were obtainable in 74% of eyes examined. Choroidal thickness and area measurements had strong inter-observer correlation (r = 0.92, P < .0001 and r = 0.93, P < .0001 respectively). Area had a moderate negative correlation with age (r = −0.62, P < .0001) that was comparable to the correlation between mean subfoveal choroidal thickness and age (r = −0.61, P < .0001). Retinal and choroidal thickness were found to be poorly correlated (r = −0.23, P = .18). Mean choroidal thickness showed a pattern of thinnest choroid nasally, thickening in the subfoveal region, and then thinning again temporally. Mean subfoveal choroidal thickness was found to be 272 μm (SD, ± 81 μm).

Conclusions

Choroidal thickness can be measured using SD-OCT high-definition raster scans in the majority of eyes. Choroidal thickness across the macula demonstrates a thin choroid nasally, thickest subfoveally, and again thinner temporally, and a trend toward decreasing choroidal thickness with age.

Section snippets

Methods

A retrospective analysis was performed on 34 eyes of 34 normal patients, who underwent high-definition 1-line raster scanning at the New England Eye Center, Tufts Medical Center, Boston, Massachusetts, between November 23, 2009 and December 21, 2009. Medical chart review was done to identify patients with no retinal or choroidal pathology. Patients with a myopic refractive error of greater than −6.0 diopters were excluded from this study. Cirrus HD-OCT scans were obtained from patients as part

Results

The group of 34 subjects consisted of 17 men and 17 women, with an average age of 51.1 years (range, 22 to 78 years). Nine out of 34 were undilated volunteers. All eyes had normal foveal contour with no retinal pathology and no abnormalities of the choroid. The delineation between choroid and sclera could be visualized easily to permit reliable thickness measurements to be performed in 34 out of 46 (74%) of the images evaluated in this study. Of the 12 normal eyes in which choroidal thickness

Discussion

The choroid is a highly vascular tissue, necessitating in vivo imaging to accurately determine its true structure and thickness. Until recently, information regarding choroidal thickness in normal eyes was based primarily on histologic results, which do not necessarily reflect the true measurements of this dynamic tissue. OCT has been well established as an accurate imaging study of known retinal pathology through good correlation between histology of animals and humans in vivo;17 however,

Varsha Manjunath graduated with high honors with a Bachelor of Science degree from McGill University, Quebec, Canada, and is presently between her third and fourth year of medical school at Drexel University College of Medicine, Philadelphia, Pennsylvania. She was awarded the of the Research to Prevent Blindness Medical Student Eye Research Fellowship in 2009, and is currently involved in a one-year research fellowship at the New England Eye Center investigating retinal diseases using prototype

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Varsha Manjunath graduated with high honors with a Bachelor of Science degree from McGill University, Quebec, Canada, and is presently between her third and fourth year of medical school at Drexel University College of Medicine, Philadelphia, Pennsylvania. She was awarded the of the Research to Prevent Blindness Medical Student Eye Research Fellowship in 2009, and is currently involved in a one-year research fellowship at the New England Eye Center investigating retinal diseases using prototype and commercial optical coherence tomography devices.

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