Abstract
Purpose: :
The aims of this study are to 1) evaluate and compare the symmetry of choroidal thickness between the right eye and left eye in patients with normal retinas, dry age-related macular degeneration (AMD) in both eyes, and dry AMD in one eye and wet AMD in the other, and 2) determine if the difference in choroidal thickness between the two eyes is correlated with age.
Methods: :
Enhanced Depth Imaging with a spectral domain optical coherence tomography (Spectralis, Heidelberg Engineering, Germany) was obtained in 20 patients with normal eyes, 18 patients with dry AMD in both eyes, and 17 patients with dry AMD in one eye and wet AMD in the other eye. ImageJ software was used to manually measure the choroidal thickness underneath the fovea, from the bottom of the retinal pigment epithelial layer to the chorioscleral border.
Results: :
For 20 patients with normal eyes (mean age=66.8+9.1 years old), the mean subfoveal choroidal thickness (SCT) of the right eye was 240.44+ 38.21 um and the left eye was 231.33 +36.23 um. The mean difference between the two eyes for SCT was 19.3 um (range: 0-50 um). The mean SCT between two eyes was not statistically significant (p=0.11). Measures of SCT in the right and left eye were strongly correlated (R=0.79, p<0.0001). For 18 patients with bilateral dry AMD (mean age=76+11.5 years old), mean difference in SCT between two eyes was 37.8 um (range: 4-92 um). The mean SCT between right eye (mean=166.67 + 83.12 um) and left eye (mean=167.72+96.16 um) was not statistically significant (p=0.93). Measures of SCT in left and right eye were strongly correlated (R=0.86, p<0.0001). For the 17 patients (mean age=81+7 years old), the SCT difference between two eyes of each patient was an average of 30.8 um (range: 0-160 um). The mean SCT of the dry AMD eye (mean=229.35 +107.94 um) did not differ significantly from the eye with wet AMD (mean=217.71+121.98 um) (p=0.30). Measures of the SCT in the dry AMD and wet AMD eye (R=0.93, p<0.0001) were strongly correlated. There was no statistically significant association between difference in choroidal thickness of two eyes and age for the three groups. The choroidal thickness difference between two eyes did not differ by disease status (p=0.74).
Conclusions: :
There was a high degree of bilateral symmetry in subfoveal choroidal thickness, regardless of whether the eyes are normal or affected by AMD and both eyes appeared to be similarly affected by age. There was no significant difference between mean SCT of the right and left eye among the three groups, suggesting that eyes with AMD do not differ significantly from normal eyes in choroidal thickness.
Keywords: imaging/image analysis: clinical • choroid • age-related macular degeneration