[Observation of orthokeratology discontinuation].
OBJECTIVE
To observe the change of teenagers with short-time and long-time orthokeratology discontinuation, including diopters, corneal curvature, corneal topography, axial length, and central corneal thickness, and to investigate the refractive correction methods after long-time orthokeratology discontinuation.


METHODS
Retrospective study. A total of 141 patients (257 eyes) with a history of wearing and discontinuing wearing orthokeratology lenses in our center were collected. According to the spherical equivalent diopters, the patients were divided into two groups (< or = -4.00 D for group I and -4.00 D for group II). Each group was further divided into two sub-groups by the discontinuation time (1 to 3 months for sub-group A and more than 3 months for sub-group B). Four sub-groups were named as I A, II A, I B, and II B. Some optical examinations were performed for the patients before orthokeratology lens wearing and after orthokeratology discontinuation, such as refraction, corneal curvature, corneal topography, corneal endothelial cells, axial length, and central corneal thickness measurement. The refractive correction methods used by patients who had long-term orthokeratology discontinuation were recorded. The observed data were analyzed with paired t-test and one-way ANOVA by SPSS16.


RESULTS
The statistically significant changes (t = 3.222, 3.404, 3.141, 5.012, P < 0.05) of spherical diopter values were (-0.31 +/- 0.58) D, (-0.48 +/- 0.68) D, (-0.35 +/- 0.65) D, and (-0.57 +/- 0.58) D for groups IA, IB, IIA, and IIB, respectively. astigmatism of the four sub-groups had no significant change (P > 0.05) The average annual spherical growth was (-0.08 +/- 0.17) D, (-0.12 +/- 0.17) D, (-0.07 +/- 0.19) D, and (-0.15 +/- 0.16) D, respectively, for the four sub-groups, and there was no statistically significant difference among them (F = 1.180, P > 0.05). Compared to the state before wearing orthokeratology lenses, the corneal curvature measured by an autorefractor was statistically different for groups I A and I A, but not statistically different for groups I B and II B. For the long-time discontinuation groups, only the SRI of the corneal topography had a statistically significant decrease compared to the value before wearing orthokeratology lenses, and others had no significant change. The average annual increase of axial length was (0.22 +/- 0.16) mm and (0.16 +/- 0.10) mm for groups IA and IB, respectively, and the increase was statistically significant (P < 0.05), but there was no significant difference between the two sub-groups (F = 1.908, P > 0.05). The central corneal thickness had no significant change (t = 1.971, 2.017, P > 0.05). The rates of the refractive correction methods after long-time discontinuation were 36.7%, 22.4%, 22.4%, 12.4%, and 6.1% for spectacles, rigid gas permeable contact lenses, soft contact lenses, either spectacles or soft contact lenses, and refractive operations, respectively.


CONCLUSIONS
The corneal morphology and central corneal thickness returned to the original after three months of discontinuation of orthokeratology. The myopia had no significant growth after discontinuation, and there was no significant difference between low to moderate and relatively high myopia.
Lina
L
Yang
Xi
X
Guo
Peiying
P
Xie
D000293:Adolescent; D001251:Astigmatism / Q000473:pathology / Q000628:therapy*; D001699:Biometry; D003261:Contact Lenses; D003263:Contact Lenses, Hydrophilic; D003315:Cornea; D063171:Corneal Pachymetry; D019781:Corneal Topography; D006801:Humans; D009216:Myopia / Q000473:pathology / Q000628:therapy*; D009907:Optometry / Q000295:instrumentation; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome