The Influence of Overnight Orthokeratology on Ocular Surface and Meibomian Gland Dysfunction in Teenagers with Myopia

Abstract

Purpose The aim of this study was to investigate the effect of overnight orthokeratology (OOK) on ocular surface and meibomian gland dysfunction in teenagers with myopia. Methods A total of 59 subjects were recruited in this prospective study. The following tests were performed before and after 1, 3, 6, 12, and 24 months of OOK lens wear, including ocular surface disease index (OSDI) questionnaire, slit-lamp examination, and Keratograph 5M. Results No infectious keratitis occurred during the study. OSDI scores increased gradually and reached the maximum at 6 months of OOK wear (P < 0.001). The meniscus height was significantly increased at 1 and 3 months after the initiation of OOK (P=0.006, P=0.035). The corneal fluorescein staining at 1, 3, 6, 12, and 24 months after wearing OOK were all increased than the prewearing level with significant difference (P=0.014, P=0.036, P < 0.001, P < 0.001, and P=0.008, respectively). The first and the average tear film NIKBUT were all higher than the prewearing level, but there was no significant difference between every follow-up time points (P > 0.05). The lid margin abnormalities were significantly increased (P=0.003, P=0.038, and P=0.015) at 6, 12, and 24 months after the initiation of OOK. There was no significant difference in the meibomian gland orifice scores at each follow-up time points compared to the prewearing level (P > 0.05). The meibomian gland lipid secretion scores after wearing OOK were higher than those of the prewearing level, however, without statistically significant difference (P > 0.05). No significant differences of the degree of difficulty of lipid excretions were detected after the initiation of OOK (P > 0.05). There was no significant difference in meibomian gland dropout scores between all follow-up time points and the prewearing level (P=1.000). Conclusion OOK increased the symptoms of dry eye and decreased the function of tear film by affecting the meniscus height and BUT. OOK did not affect the function of meibomian glands.Clinical Study registration number: ChiCTR18000185708.

Analysis of tear film spatial instability for pediatric myopia under treatment

“…The population of children treated with atropine and orthokeratology is increasing every year and the potential ocular surface damage should not be underestimated. Ocular surface damages caused by these treatments are generally initiated by tear film instability 12,17,19,30 . Therefore, thorough understanding of the tear film stability is highly important for pediatric myopia control.…”

“…Only a healthy ocular surface can provide a smooth optical surface for visual function and a normal tear film plays a dominant role in it 31 . Though tear film instability, which might be the initiator of severe ocular surface disease, has not yet been reported in myopic children under atropine control, it was recently announced and noticed as an unignorable risk in children under orthokeratology control 12,13,15,32 . Some researchers debated about the ocular surface alterations after overnight wearing of orthokeratology lenses.…”

“…Na et al proposed that overnight wearing of orthokeratology lenses may cause changes in the meibomian glands and tear film stability 15 . Wang et al 12 reported that overnight wearing of orthokeratology lenses could decrease TMH and TBUT but did not affect the function of the meibomian glands. However, Li et al 32 and Xie et al 13 pointed out that basal tear secretion and ocular surface inflammation were unaffected after orthokeratology treatment and there was only a short-term decrease in TBUT.…”

“…Microbial keratitis is a rare but unneglectable vision-threatening complication with an estimated incidence rate of 7.7 cases per 10,000 patient years, similar in extended or overnight lens wear 11 , 14 , 30 , which can be prevented by a normal tear film. Therefore, the concern over tear film instability in children is increasing and was announced recently, especially for myopic children under orthokeratology treatment 12 – 15 .…”

“…Wearing the orthokeratology lens is thought to alter the ocular surface and induce tear film instability, potentially causing severe ocular surface complications in myopic children under treatment 17 – 19 . The possible mechanisms associated with tear film instability may include thinning of the tear film lipid layer as a result of the loss of meibomian glands based on contact-lens-induced aggregation of desquamated epithelial cells into keratotic clusters that block the meibomian duct 12 , 17 , 19 , conjunctival fold and metaplasia, reduction in goblet cell density, lid wiper epitheliopathy 18 , and upregulation of proinflammatory mediators induced by tissue reshaping 20 . However, no consensus has been reached till now.…”