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Five‐year change in refraction and its ocular components in the 40‐ to 64‐year‐old population of the Shahroud eye cohort study
Author(s) -
Hashemi Hassan,
Khabazkhoob Mehdi,
Iribarren Rafael,
Emamian Mohammad Hassan,
Fotouhi Akbar
Publication year - 2016
Publication title -
clinical and experimental ophthalmology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.3
H-Index - 74
eISSN - 1442-9071
pISSN - 1442-6404
DOI - 10.1111/ceo.12753
Subject(s) - medicine , dioptre , refraction , ophthalmology , optometry , population , visual acuity , subjective refraction , refractive error , optics , physics , environmental health
Background To assess 5‐year refractive changes and their related factors in the 40‐ to 64‐year‐old population of Shahroud, Iran. Design Prospective cohort study. Participants Of the 5190 participants of Phase I, 4737 participated in Phase II (response rate = 91.3%). Methods Participants were tested by refraction, visual acuity, slit‐lamp biomicroscopy, ophthalmoscopy and biometry. Myopia was defined as a spherical equivalent more negative than −0.5 dioptre (D) and hyperopia as a spherical equivalent more positive than +0.5 D. Main Outcome Measures Mean 5‐year change in spherical equivalent refraction. Results The mean 5‐year change in spherical equivalent refraction was +0.24 D (95% CI: +0.22 to +0.25). After 5 years, 4.77% (95% CI: 4.08 to 5.46) of subjects developed at least 0.5 D of myopia and 22.27% (95% CI: 20.97 to 23.57) developed at least 0.5 D of hyperopia. Five‐year changes in refraction included a hyperopic shift in all age groups. The greatest hyperopic shift was seen in middle‐aged women. The greatest loss of lens power was observed in hyperopic women and the least in myopic men. Nuclear cataract was associated with a myopic shift in refraction. The axial length and the corneal power had very small changes during this period. Myopes showed the greatest increase in axial length. Corneal power increased by a very small amount in all refractive groups. Conclusions The most important biometric index related to hyperopic shifts, which were greater in magnitude in women, was loss of lens power, whereas nuclear cataract was associated with myopic shifts.