Analysis of anterior corneal surface shape after replacing orthokeratology lenses carrying a small base curve diameter

• Published in: Frontiers in neuroscience Vol. 18; p. 1424394
• Main Authors: Chen, Minfeng, Zhao, Sijun, Peng, Lulu, Rong, Yu, Zhu, Chengwei, Lu, Fan, Mao, Xinjie
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Media S.A 18.11.2024
• Subjects: axial length; base curve; decentration distance; myopia; Neuroscience; orthokeratology; myopia; orthokeratology; decentration distance; axial length; base curve
• ISSN: 1662-453X; 1662-4548; 1662-453X
• DOI: 10.3389/fnins.2024.1424394

The study analyzed the changes in corneal surface shape after replacing orthokeratology lenses carrying a small base curve (BC) diameter. In this retrospective study, we included ~54 right eyes belonging to 54 myopic children who insisted on wearing an orthokeratology (ortho-k BC 6.0 mm) lens for more than 12 months and then replaced the second ortho-k (BC 6.0 mm or BC 5.0 mm) lens ~12 months. The children were categorized into two groups based on the design of the BC of the replaced ortho-k lens 6.0/5.0 and 6.0/6.0. The ratio of axial length (AL) elongation in the 6.0/5.0 group was significantly less than in the 6.0/6.0 group (-0.015 ± 0.014 mm/M vs. -0.005 ± 0.012 mm/M, = -2.672, = 0.010). After replacing the BC 5.0 ortho-k lens, the optical zone (8.19 ± 2.60 mm vs. 9.64 ± 1.57 mm , = -2.345, = 0.023), reverse zone (31.64 ± 5.80 mm vs. 34.86 ± 4.61 mm , = -2.169, = 0.035), and treatment zone (17.16 ± 3.94 mm vs. 22.96 ± 2.59 mm , = -6.049, < 0.001) were all smaller than those in the 6.0/6.0 group. In the 6.0/5.0 group, the optical zone (wearing more than 1 month as first: 11.16 ± 2.12 mm , the last inspection before replacing lens as before: 10.87 ± 1.90 mm ), reverse curve zone (first: 22.03 ± 3.11 mm , before: 26.24 ± 5.06 mm ), and treatment zone (first: 35.97 ± 5.54 mm , before: 37.11 ± 6.04 mm ) were all greater than these after replacing ortho-k lens (all < 0.001). Replacing an ortho-k lens with a smaller BC resulted in a larger decrease in the mean central corneal zone and a substantial increase in the paracentral corneal zone. In addition, the ortho-k lens with a smaller BC does not increase the decentration distance and contributes to effective myopia control.