Abstract
Purpose :
To investigate choroid thicknesses change after orthokeratology both at horizontal and vertical meridians with spectral domain optical coherence tomography. Analysis the correlation of choroid thickness change with refractive error and ocular biological parameters change.
Methods :
Subjects with low or moderate myopia (–1 D to –6 D) were asked to wear orthokeratology lens for 3 months. Scans through the fovea both from horizontal and vertical meridians were acquired with Cirrus OCT. Around the fovea, the choroid equivalent to a 3.50 mm chord distance, were selected for data analysis. Choroid thicknesses (CT) were acquired by custom software. The analyzed regions were divided into 7 equal zones. Ocular biological parameters were detected by Lenstar during the period of study. Two-tailed Student’s t-test was used to evaluate CT at each zone before and after orthokeratology lens wear.
Results :
Total 30 subjects were enrolled. The mean age of all subjects was 11.3±1.7 years old. The mean CT was 253.1 ± 38.6 µm in macular zone, 273.1 ± 31.8 µm in temporal zone and 194.8 ± 52.2 µm in nasal zone at baseline. After 3 months lens wear, the mean CT was 262.8 ± 44.3 µm in macular zone, 287.2 ± 40.1 µm in temporal zone and 203.2 ± 51.2 µm in nasal zone respectively. The mean CT was not significantly change in each zone of vertical meridian. (P>0.05) The mean CT was increased in each zone of horizontal meridian. (P<0.05) The CT thicken most in temporal zone up to 13.5 ± 22.5 µm. In nasal zone, the choroid thickness thicken about 8.4 ± 14.2 µm. The axial length increased 0.04 mm after 3 months lens wear, while the changes of axial length were not significantly (P>0.05). The negative correlations of the choroid thickness thicken with the axial length changes were found in the temporal and nasal zones. (r : -0.3~-0.4, P<0.05).
Conclusions :
The thickest choroid was in the temporal and the thinnest in the nasal region at baseline. After otthokeratology lens wearing for 3 months, the choroid thicknesses increased in horizontal meridian but not in vertical meridian. Choroid thickness changes were negative related to the changes of axial length. This study hint that the choroid may play some role in myopia control during orthokeratology.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.