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Nuclear Cataract and Myopic Shift in Refraction

2007; Elsevier BV; Volume: 144; Issue: 3 Linguagem: Inglês

10.1016/j.ajo.2007.05.003

1879-1891

Chameen Samarawickrama, Jie Jin Wang, George Burlutsky, Ava Grace Tan, Paul Mitchell,

Corneal surgery and disorders

Purpose Nuclear cataract is thought to cause a myopic shift in refraction in older persons. The authors tested this hypothesis by assessing the correlation of nuclear opacity with spherical equivalent refraction (SER) in an older population. Design Population-based cross-sectional study. Methods Three thousand six hundred and fifty-four participants aged 49 years or older were examined in the Blue Mountains Eye Study [BMES] (1992 to 1994). Eye examinations included subjective refraction and lens photographs. Nuclear opacity was assessed against four standard slit-lamp lens photographs using the Wisconsin Cataract Grading System. Nuclear cataract was defined as opacity level 4 or higher. Results Participants without nuclear cataract had an annual mean hyperopic shift of 0.05 diopters ( P < .0001). In persons with nuclear cataract, this hyperopic shift disappeared. A myopic refractive shift occurred only in persons with nuclear opacity levels of 4 or higher. Conclusion This study documents the contribution of nuclear cataract to the mild myopic shift that neutralizes the age-related hyperopic shift occurring in older persons.