Effect of overnight orthokeratology lenses on tear film stability in children

To assess the tear film surface quality after orthokeratology using an automated Medmont E300 corneal topographer.Children who wore orthokeratology lenses for more than one year were selected in this retrospective study. Tear film disruption (TFD) and central tear film disruption (cTFD) were measured with Medmont E300 corneal topographer at initial and each follow-up visit after fitting with orthokeratology lenses, providing a nominal value from 0 (perfect) to 1 (poor). Tear film surface quality before and after ortho-k treatment was compared.145 children using orthokeratology lenses were observed. TFD and cTFD significantly increased at 1-day follow up (TFD, t = -17.3, P < 0.001; cTFD, t = -10.4, P < 0.001). This change remained consistent through to 12-months visit (TFD, F = 51.1, P < 0.001; cTFD, F = 28.0, P < 0.001). A sub-group of n = 11 children were discontinued for 1-month before being refit with OrthoK lenses of a different design. Similarly, there was a significant increase in TFD compared to pre-orthoK scans (0.172 ± 0.161), but this returned to baseline levels after ceasing lens wear (0.084 ± 0.059). A sub-group of monocular OrthoK wearers (n = 23) found that TFD and cTFD values increased in eyes with monocular lens-wearing but remained stable in the lateral eyes.Objective measurements of tear-film quality are reduced in children after fitting with orthokeratology lenses, but return to baseline after 1-month of lens cessation. It is of importance to ensure tear film surface quality is continuously monitored throughout use of orthoK lenses.