Wearing ortho-K lenses for over 12 months did not significantly affect the tear film quality and the number of meibomian glands in children. Photo: Dan Fuller, OD. Click image to enlarge.

The momentum for bringing myopia management efforts into mainstream practice has more practitioners than ever training to implement techniques like orthokeratology (ortho-K). However, there is little data on the safety of long-term overnight wear in terms of corneal health and tear film quality. In a new study, researchers investigated the effect of overnight ortho-K lenses on tear film stability and meibomian gland status in children between the ages of eight and 15. They found they weren’t significantly affected, suggesting that continuous use of ortho-K lenses for 12 months has a minimal effect on the ocular surface.

A total of 33 children with monocular myopia who were prescribed ortho-K lenses for at least one year were evaluated. The experimental group (ortho-K lens on myopic eye) and control group (non-myopic eye of the same participant) each included 33 eyes. The researchers believed that setting up the groups this way reduced the impact of most of the confounding factors on the experimental results. Tear film stability and meibomian gland status were measured using a Keratograph 5M (Oculus).

No significant difference was observed in loss of meibomian glands or noninvasive average tear film break-up time between both groups. At the one-year visit, the non-invasive first tear film break-up time values were 6.15s and 6.18s in the experimental and control groups, respectively. The lower tear meniscus height was 18.74μm and 18.65μm in these groups, respectively. The researchers found no significant difference in dry eye symptoms, height of the lacrimal river and meibomian gland function between the groups.

“Overnight use of ortho-K lenses had a minimal effect on the ocular sur­face, while controlling the axial growth of the eye,” the authors concluded. “Its overnight use could be considered safe because it did not significantly change the ocular surface environment or affect meibomian gland function.”

The authors noted that this finding can help guide the clinical management of tear film quality with respect to the use of ortho-K lenses.