Topographic variation and interocular symmetry of macular choroidal thickness using enhanced depth imaging optical coherence tomography.
OBJECTIVE
To report and analyze factors influencing topographical and interocular variations in choroidal thickness (CT) in a healthy adult population.


METHODS
One hundred eyes of 50 healthy subjects underwent visual acuity and axial length measurements and optical coherence tomography (OCT) with enhanced depth imaging (EDI). CTs at the fovea and at 3 mm nasal, temporal, superior, and inferior to the fovea were measured manually. Topographic variation, relative interocular differences in CT and predictors of CT were analyzed. The relationships between interocular differences in CT and differences in age and interocular axial length were explored.


RESULTS
The mean (SD) foveal CT in the right and left eyes were 334 (95) and 333 (90) μm, respectively. For foveal CT, there was a high correlation between the two eyes (r = 0.90) with a relative interocular 95% limits of agreement of -80 to +83, and a median (range) absolute difference of 21 (0.4-135). There was no significant variation in the relative and absolute interocular differences in CT. Axial length was the main predictor of CT for nasal and foveal CT. Symmetry in CT in the horizontal and vertical meridians was seen in eyes with axial length shorter than 23.50 mm (P < 0.05).


CONCLUSIONS
There was no significant relative interocular difference in CT. Axial length contributes to some of the variances in CT but has a significant influence on the CT profile. Although relative interocular difference is not significant, absolute interocular differences in CT may reach 85 μm.
Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), University of Western Australia, 2 Verdun Street, Nedlands, WA, Australia. nfredchen@lei.org.au
Fred K
FK
Chen
Jonathan
J
Yeoh
Waheeda
W
Rahman
Praveen J
PJ
Patel
Adnan
A
Tufail
Lyndon
L
Da Cruz
D000328:Adult; D002829:Choroid / Q000166:cytology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D008266:Macula Lutea / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D041623:Tomography, Optical Coherence / Q000379:methods*