Purchase this article with an account.
Yuko Shibata, Hiroshi Uozato, Masakazu Hirota, Takushi Kawamorita; Change of corneal curvature under the open eye condition and the slightly closed eye condition. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1645.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To assess the influence of squinted eyes, we measured corneal curvature under the condition of widely opened eye and the condition of slightly closed eye.
39 eyes of 20 healthy subjects (age 21 - 42 yrs) participated in this study. Corneal curvatures of central zone (1 - 4 mm as a diameter) were measured and front photo images of the eyelids and eye were obtained at the same time by an anterior segment imaging analyzer (Galilei, Ziemer Ophthalmic Systems, Port, Switzerland) under both a condition with the eye opened widely and a condition with the eye closed slightly in which subjects opened their eyes narrowly with consciousness.
The group mean size of slightly closed eye was 67.0 ± 12.2 % of that of widely opened eye condition (Range: 45.9 - 89.5%). The mean SimK value average of widely opened eye was 43.59 ± 1.39 D and that of slightly closed eye was 43.44 ± 1.57 D, the mean flat SimK value of widely opened eye was 42.82 ± 1.32 D and that of slightly closed eyes was 42.35 ± 1.84 D and the mean steep SimK value of widely opened eye was 44.36 ± 1.53 D and that of slightly closed eye was 44.52 ± 1.69 D. Significant differences were found in flat SimK value and steep SimK value between two conditions (Wilcoxon signed-ranks test, p < 0.05) but there was no significant difference in SimK value average. The mean anterior instantaneous curvature Mean K of widely opened eye was 43.03 ±1.30 D and that of slightly closed eye was 42.98 ± 1.59 D, the mean anterior instantaneous curvature Flat K of opened eye was 42.23 ± 1.28 D and that of slightly closed eye was 41.83 ± 1.63 D and the mean anterior instantaneous curvature Steep K of opened eye was 43.82 ± 1.42 D and that of slightly closed eye was 44.13 ± 1.91 D. There was no significant difference in anterior instantaneous curvature values of two conditions (Wilcoxon signed-ranks test, p > 0.05).
Data obtained in this study shows that in the slightly closed eye condition, cornea curvature of central zone had a little change to become more astigmatic. It was suggested that even in the slightly closed eye condition, corneal curvature was affected by the eyelids and tear film’s distribution.
This PDF is available to Subscribers Only