Corneal edema may result from long-term wear of orthokeratology (OK) lenses in children, according to research published in Contact Lens and Anterior Eye. Secondary findings also revealed that baseline refractive error was not associated with changes in corneal volume, densitometry, or pachymetry.
Researchers retrospectively analyzed 28 eyes of 28 participants treated with OK (mean age 12.03±3.80 years, mean OK duration 666 days) between 2013 and 2018. They recorded the volume of the central 10mm cornea, densitometry measurements (central, nasal, and temporal cornea), and pachymetry readings (horizontal and vertical) at baseline. The team also obtained follow-up data at 1 day, 1 week, 1 month, 3 months, and every 6 months following the initial visit.
According to the report, baseline spherical equivalent (SE) was -3.03±1.56 D among the cohort. The investigators noted a significant association between OK lens wear and corneal volume between baseline and final visit (+0.91±1.50 mm3 and +1.57±1.60 mm3, respectively, P <.001). They also reported an increase in corneal densitometry, but it did not reach statistical significance or correlate with baseline SE (P >.05 for both). The team did note significant changes in pachymetry for mid-peripheral regions of the cornea across baseline, 1-day, and final visits for the nasal 3 mm cornea (P =.01) and inferior 3 mm cornea (P =.005), but did not observe significant changes for the central cornea as a whole (P >.05). Overall, researchers determined that baseline refractive error did not correlate with changes in corneal volume, densitometry, or pachymetry.
“An increase in corneal volume, densitometry and pachymetry of the mid-peripheral cornea was found with long-term OK wear,” according to the investigators. Despite an anticipated thinning effect witnessed with OK lenses, “these changes may indicate the presence of corneal edema with long-term OK wear in young myopes.”
Study limitations include a small sample size, single center design, and the use of only 1 type of OK lens.
Zhang YE, Ouzzani M, Wright C, Sorbara L. Changes in corneal thickness, corneal volume, and densitometry after long-term orthokeratology wear. Cont Lens Anterior Eye. Published online May 9, 2022. doi:10.1016/j.clae.2022.101703