| Purpose: To study the relationships between the refractive power of the crystalline lens, the overall refractive error of the eye, and the degree of nuclear cataract in older participants of a population-based study.
Participants: All phakic participants from the population-based Central India Eye and Medical Study aged 50 years or over (1885 subjects).
Methods: The subjects underwent a medical and detailed ophthalmological examination including refractometry, keratometry, standardized assessment of nuclear cataract, and sonographic measurement of the anterior chamber depth, lens thickness and axial length. The calculation of the refractive power of the lens was based on distance non-cycloplegic refractive error, corneal refractive power, anterior chamber depth, lens thickness and axial length using Bennett´s formula. The A and B constants in Bennett´s formula were calculated using Gullstrand’s reduced eye model.
Results: The study included 1885 (914 (48.5%) men) subjects with a mean age of 60.8±8.2 years (range: 50 to 100 years). Mean refractive lens power was 25.5±3.0 diopters (13.9 to 36.6 diopters). The correlation coefficients (r) of the association with refractive error were highest for crystalline lens power (r= -0.44; P<0.001) and nuclear lens opacity grade (r= -0.44; P<0.001), followed by axial length (r= -0.37; P<0.001). They were lowest for corneal refractive power (r= -0.05; P=0.05) and anterior chamber depth (r= -0.06; P=0.01). In multivariate analysis, refractive error was significantly (P<0.001) associated with lower refractive lens power, shorter axial length, less marked nuclear lens opacity and deeper anterior chamber. Correspondingly, crystalline lens power was significantly lower in hyperopic subjects and significantly higher in myopic subjects than in emmetropic subjects, particularly in subjects with greater nuclear opacity. Lens thickness was significantly lower in eyes with greater nuclear opacity.
Conclusions: Variations in refractive error in adults aged 50+ years were mostly influenced by variations in crystalline lens power and axial length, and only to a minor degree by variations in other ocular biometric variables such as corneal refractive power, anterior chamber depth and lens thickness. |
网友评论：（只显示最新10条。评论内容只代表网友观点，与本站立场无关！）