Short-term effect of Ortho-K on axial length and choroidal thickness

Abstract

Purpose. To investigate the short-term effect of orthokerato- logy (ortho-k) on choroidal thickness (CHT), anterior chamber depth (ACD), central corneal thickness (CCT), and its rela- tionship to the change in axial length (AL). Material and Methods. Sixteen eyes of sixteen adult (age 25 - 54 years) ortho-k lens wearers discontinued treatment for one month. Measurements were taken before discontinua- tion, at the end of the break, and 2 - 4 weeks after resuming ortho-k lens wear. CHT was measured subfoveally and then nasally, as well as temporally of the fovea at 4 locations. Meas- urements were taken between 2 and 6 pm. Results. No significant change in subfoveal CHT was found. The CHT decreased significantly only 1 and 1.5 mm nasally after discontinuation (-12 ± 21 µm p = 0.035 and -13 ± 17 µm p = 0.006) and increased 0.5 mm temporally after resuming the lens wear (+11 ± 17 µm p = 0.025). Both CCT and ACD increased significantly after discontinuation of ortho-k lens wear (+8 ± 11.0 µm p = 0.01 and +0.04 ± 0.05 mm p = 0.005) and then decreased again after resuming ortho-k lens wear (-7 ± 11 µm p = 0.03 and -0.05 ± 0.07 mm p = 0.009). AL did not change significantly between any of the study phases and correlated significantly negatively with CHT, but with no other parameters. Conclusion. Subfoveal CHT did not change significantly due to short-term ortho-k lens treatment in adults. AL was not affected by the treatment either, despite the increase in ACD after discontinuation. Thus, ortho-k does not seem to have a short-term influence on AL. Keywords orthokeratology, choroidal thickness, myopia, myopia control, axial length, OCT