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Hiroshi Sasaki, Natsuko Hatsusaka, Eri Shibuya, Norihiro Mita, Ayako Okamoto, Hiromi Osada, Masami Kojima, Eri Kubo, Kazuyuki Sasaki, Fridbert Jonasson; 12-year Change Of Crystalline Lens Power By Opacity Type Reykjavik Eye Study. Invest. Ophthalmol. Vis. Sci. 2012;53(14):3027.
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© ARVO (1962-2015); The Authors (2016-present)
Cortical opacity concomitant with water clefts (WC) may cause hyperopia. We reported that WC, which usually develop at the Y-suture, led to reduced power of crystalline lens. We followed-up Icelanders for 12 years and investigated change of refractive power of crystalline lens by opacity type.
Among 1045 subjects who joined the Reykjavik Eye Study (RES) in 1996, 573 subjects participated in 2008. From those 398 right eyes that had transparent lens and no evidence of WC (age 58.1±6.1 yrs) in 1996 were selected as subjects in this study. They were grouped as transparent or with only one of the 3 main types of cataract (302, transparent ;, 56, cortical; 33, nuclear, and 7, PSC). Eyes with transparent lens and cortical opacity were further classified by presence of WC (within 3-mm central optical zone (Central: C) and outside (Peripheral: P)). Lens power (LP) was calculated from refractive power, corneal refractive power, and axial length by Olsen's method (Acta Ophthalmol Scand. 2007).
Spherical equivalent (SE) increased by 0.6D (0.6±1.8D to 1.2±1.8D) over 12 yrs in transparent group. In these eyes LP significantly decreased by 1.04D (22.5±2.2D to 21.5±2.2D) (p<0.05), while LP decreased by 1.03D (21.8±2.0D to 20.8±2.3D) in cortical group, with no significant difference between these groups. LP increased by 0.29D (21.1±2.1D to 21.4±2.4D) in nuclear group. Hyperopia in eyes with WC (C) in transparent and cortical groups worsened by 1.39±0.82D, as LP decreased by 2.24D which was significant compared with eyes without WC (p<0.05). WC (P) had no influence on LP.
Eyes aged >50 yrs with transparent lens, and those with cortical opacity, develop hyperopia at the rate of 0.5D a decade with decreasing refractive power, whereas those with nuclear opacity became slightly myopic. Water cleft located within the 3-mm central optical zone is an important factor of hyperopia due to decreased lens refractive power.
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