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Lesley Doyle, Julie-Anne Little, Kathryn Saunders; Repeatability of Crystalline Lens Thickness Measurements in the Accommodating Eye. Invest. Ophthalmol. Vis. Sci. 2013;54(15):3581. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the repeatability of lens thickness (LT) measurements taken using the Visante Anterior Segment Optical Coherence Tomographer (AS-OCT) (Zeiss Meditec, Germany) for the first time under non-cycloplegic and accommodative conditions.
Participants were 66 visually normal adults, (18 -75 years), stratified into five age groups (18-29, 30-39, 40-49, 50-59 and 60-75 years). Images of the crystalline lens were taken during stimulation of accommodation at demands of 0, 1, 2, 3, 4, 5 and 8D. Raw lens images were analysed using a refractive index n=1.42. Participants returned for repeat measures on another occasion.
LT measures were obtained from 90% of images. The mean interval between visit 1 and visit 2 was 12.68+/-26.80 days. The mean difference between visits for LT measurements in the unaccommodated state for all participants was -0.0001mm with 95% limits of agreement from -0.051 to 0.051mm. Over the range of accommodative demands the 95% limits of agreement were widest for the 18-29-year-old age group, ranging from -0.034 to 0.043mm for a 2D accommodative demand to -0.120 to 0.171mm for a 5D demand and narrowest for the 60-75-year-old age group, ranging from -0.023 to 0.017mm for a 3D demand to -0.033 to 0.033mm for a 4D demand. When considering the 95% limits of agreement across accommodative demands there was no significant difference with increasing demand (repeated measures ANOVA, F(6, 24)= 1.30, p>0.05) however the 95% limits of agreement were significantly smaller in the 50-59 and 60-75-year-olds in comparison to the younger age groups (one-way ANOVA, F(4, 30)= 6.11, p<0.05).
Our data demonstrates similar repeatability compared with a previous study in children under cycloplegia (Lehman et al., 2009). Repeatability does not deteriorate significantly with increasing accommodative effort and was shown to improve with increasing age. The ability to detect small changes in LT with good repeatability indicates the suitability of the Visante AS-OCT when studying changes in LT both with age and under accommodative conditions.
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