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Shweta Singhal, Stephen Stewart, Monisha Nongpiur, Hla Htoon, Shamira Perera, Tin Aung; The Impact of Lens Vault on Visual Acuity and Refractive Error in Subjects with Angle Closure. Invest. Ophthalmol. Vis. Sci. 2013;54(15):1889.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the relationship between lens vault (LV) and visual acuity in subjects with angle closure.
This was a cross-sectional study of 2047 subjects aged 50 years or more who were recruited from a community polyclinic. All participants underwent a standardized ocular examination and anterior segment optical coherence tomography (ASOCT). Customised software was used to measure LV, defined as the perpendicular distance between the anterior pole of the crystalline lens and the horizontal line joining the 2 scleral spurs, on horizontal ASOCT scans. Visual acuity was measured using a logarithm of minimum angle of resolution chart (logMAR chart, Lighthouse Inc, Long Island, New York). Visual acuity was classified as normal (logMAR<0.3), mild impairment (0.3<logMAR<0.6) and moderate/severe impairment (logMAR>0.6). Refracction was measured with an autorefractor machine (Topcon Auto K KR7100D, Topcon Corp, Tokyo, Japan). Spherical equivalent was defined as sphere plus half cylinder. An eye was defined as having angle closure if the posterior pigmented trabecular meshwork was not visualized for at least 180° on gonioscopy.
Complete data on 1453 subjects including 311 with angle closure were available for analysis. Eyes with angle closure were significantly older (p< 0.001), with shorter axial length (AL, p< 0.001) and shallower anterior chamber depth (ACD, p< 0.001). However, although eyes with angle closure had a significantly greater LV (p< 0.001), there was no significant difference in visual acuity (p=0.14) compared to those with open angles. The majority of angle closure subjects had normal visual acuity or mild visual impairment (85.2%). No significant trend was noted in visual acuity (p=0.12) or spherical equivalent (p=0.63) with increasing magnitude of LV. After adjusting for age, gender, AL, ACD, and spherical equivalent, there was no significant correlation between LV and visual acuity (p = 0.35). Similarly, no significant association was found between LV and spherical equivalent (p=0.06).
No association was found between lens vault and visual acuity or refractive error. Subjects with angle closure may have large LV but good visual acuity.
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