Background: Menicon Z night orthokeratology (OK) lenses
was introduced in Malaysia in 2015 and to date there is no
report on its effects on the cornea. The objective of this
study was to examine short term changes in corneal
thickness and morphology of endothelial cells in young
Malay adults after wearing Menicon Z night OK lenses.
Methods: Corneal thickness was measured at the central
and mid-peripheral locations of 20 participants aged
22.45±1.19 years using Tomey SP-3000 A-scan
ultrasonography. Endothelial images of the central and
peripheral locations captured using Tomey EM-3000
specular microscope were noted. Corneal thickness,
endothelial cell density (ECD), coefficient of variation in cell
size (CV), and hexagonality (HEX) at baseline, 24 hours,
three months and six months after treatment were noted and
analysed using repeated measure analysis of variance.
Results: Central corneal thickness decreased significantly
over a three-month period (p=0.001) and stabilised
thereafter. There were no significant changes in thickness in
all peripheral areas measured (p>0.05), and in ECD, CV and
HEX after the six-month period (p>0.05).
Conclusions: The current study showed that significant
thinning of central cornea and none at the mid-periphery. OK
lens wear with Menicon Z night lenses had no effects on
corneal morphology over the six month period.