Comparative Analysis of Central Corneal Thickness in Four Fish Models

To understand the left-right asymmetry of vertebrate eyes, this study measured the central corneal thickness (CCT) of Oryzias curvinotus, Oryzias melastigma, Oryzias latipes, and zebrafish with optical coherence tomography. The results showed that the CCTs were significant differences among different species and groups, even between the right and left eyes of each fish. The values of the CCTs (mean ± SD, μm) for the four species were 104.71 ± 14.49, 61.88 ± 8.63, 64.76 ± 10.36 and 56.96 ± 10.48, respectively. Moreover, comparing the two wild groups of O. curvinotus from Sanya on N18° and Gaoqiao on N21°, the CCT value for the low-latitude group was 104.71 ± 14.49 μm, greater than the high latitude group 76.13 ± 5.70 μm significantly (t-test, p = 0.0001). Lastly, the paired Student's t-test revealed that significant CCT differences existed between the left and right eye for all four species and groups, of which zebrafish and O. melastigma were belonging to the left thicker type in contrast to the others. This study laid a foundation for understanding the causes of the difference in CCT, and also provided possible fish models for human researches on keratomileusis, glaucoma, and other corneal diseases.