Mechanism for corneal reshaping in hyperopic orthokeratology.
Optom Vis Sci
; 86(4): e306-11, 2009 Apr.
Article
em En
| MEDLINE
| ID: mdl-19225436
ABSTRACT
PURPOSE:
To investigate the mechanism underlying hyperopic orthokeratology (OK) by comparing the short-term clinical effect of lenses before and after central lens fenestration.METHODS:
Twelve subjects (age 21 to 24 years) were fitted with rigid hyperopic OK lenses (BE Enterprises/Capricornia) in one eye only. The fellow eye acted as a non-lens wearing control. Lens specifications were matched to provide the same post lens tear film profile in all subjects. Non-fenestrated lenses were worn in the open eye for 1 h and in the closed eye for four nights. Subjective spherical equivalent refraction and corneal topography (Medmont E300) were measured at baseline, after 1 h of lens wear, and within 1 h of waking on days 1 and 4 of overnight lens wear. The lenses were then sent for three 0.75 mm fenestrations within the central optic zone, and lens wearing and measurement procedures were repeated.RESULTS:
There was a statistically significant change from baseline in all variables at all visits in lens wearing eyes. Refraction changed after 1 h of lens wear, with greater effect after overnight wear. Para-central corneal flattening was apparent after 1 h of lens wear, with greater flattening after overnight wear. Central corneal steepening was only statistically significant after overnight wear. Central fenestrations did not lead to a difference in clinical effect in any variables. However, a correlation between apical corneal curvature change and refractive change became apparent only after lens fenestration.CONCLUSION:
A hyperopic OK effect was established after 1 h with increased effect with longer lens wearing time. Central fenestrations did not affect the clinical outcomes, indicating that corneal compression by the lens in the para-central region as opposed to central post lens tear film suction may be the primary mechanism behind the hyperopic OK clinical effect.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Córnea
/
Procedimentos Ortoceratológicos
/
Hiperopia
Limite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
Optom Vis Sci
Assunto da revista:
OPTOMETRIA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Austrália