Refractive error changes in cortical, nuclear, and posterior subcapsular cataracts

• Published in: British journal of ophthalmology Vol. 87; no. 8; pp. 964 - 967
• Main Authors: Pesudovs, K, Elliott, D B
• Format: Journal Article
• Language: English
• Published: BMA House, Tavistock Square, London, WC1H 9JR BMJ Publishing Group Ltd 01.08.2003; BMJ; BMJ Publishing Group LTD; Copyright 2003 British Journal of Ophthalmology
• Subjects: Aged; Aged, 80 and over; Analysis of Variance; astigmatism; Astigmatism - etiology; Biological and medical sciences; Care and treatment; Cataract; Cataract - complications; Cataract - pathology; Clinical Science - Scientific Reports; Humans; Lens Cortex, Crystalline - pathology; Lens diseases; Lens Nucleus, Crystalline - pathology; Lens, Crystalline - pathology; Medical sciences; Middle Aged; myopia; Myopia - etiology; Ophthalmology; Prospective Studies; Refractive Errors - etiology; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the eye and orbit; vector analysis; Vision disorders; Human; Cataract; Change; Posterior; Refractive error
• ISSN: 0007-1161; 1468-2079
• DOI: 10.1136/bjo.87.8.964

Aims: To determine the effect of the three main morphological types of cataract on refractive error. Methods: Data were prospectively collected from 77 subjects (age 67 (SD 8) years) with one morphological type of cataract. 34 had cortical, 21 had nuclear, and 21 had posterior subcapsular cataract. 22 subjects with clear lenses (60 (7) years) were recruited as controls. The spherical equivalent and astigmatic vector change between spectacle correction and optimal refraction were calculated. Results: The cortical cataract group showed a significant astigmatic change of 0.71 (0.67) D (mean (1 SD)) compared to the control group (0.24 (0.20) D), with 24% outside the 95% confidence limit (0.63 D). The nuclear cataract group showed a significant myopic shift of −0.38 (0.60) D compared to the control group (+0.02 (0.21) D), with 52% beyond the minus 95% confidence limit (−0.39 D). Conclusion: A quarter of subjects with cortical cataract showed larger changes in astigmatism than subjects with clear lenses. This is probably because of the localised refractive index changes along cortical spoke opacities within the pupillary area. The well known myopic shift of nuclear cataract was also demonstrated.