Age-related changes in optical and biometric characteristics of emmetropic eyes (original) (raw)
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Progression and Longitudinal Biometric Changes in Highly Myopic Eyes
Investigative Opthalmology & Visual Science
PURPOSE. To examine 2-year progression rate and associated biometric changes in highly myopic eyes. METHODS. This is a longitudinal, observational cohort study that included 657 participants aged 7 to 70 years with bilateral high myopia (≤−6.00 diopters [D]) and followed for 2 years. All participants underwent ocular biometry and cycloplegic refraction examinations. Main outcome measures were changes in spherical equivalent refraction (SE) and ocular biometry in the right eyes. RESULTS. Mean age of participants was 21.6 ± 12.2 years. At baseline, mean SE was −9.82 ± 3.28 D and ocular biometric measurements were 27.40 ± 1.56 mm for axial length, 3.16 ± 0.27 mm for anterior chamber depth, 3.60 ± 0.35 mm for lens thickness, and 20.09 ± 1.50 mm for vitreous chamber depth. After 2 years of follow-up, there was a trend toward more myopia and greater axial elongation in all age groups. Younger participants (≤20 years) had significantly (P < 0.001) greater rates of myopic shift and axial elongation compared with older participants (>20 years). However, highly myopic adults aged 40 to 70 years continued to demonstrate refractive progression, particularly if they had extremely high myopia (≤−10.00 D). In the multiple regression analysis, each additional diopter of myopia at baseline was associated with a 11% higher risk of a >1.00-D/y myopic shift (odds ratio, 1.11; 95% confidence interval, 1.04-1.18; P = 0.002). CONCLUSIONS. Longitudinal data from this large Chinese cohort suggest that highly myopic eyes continue to progress in SE throughout life, with the greatest rates of progression observed in younger participants. Axial elongation rates appeared to stabilize after 20 years of age and were predominantly due to an increase in the vitreous chamber depth. Other risk factors for a myopic shift included a higher degree of myopic refraction at baseline.
A biometric investigation of late onset myopic eyes
Acta Ophthalmologica, 2009
There is a paucity of biometric information on late onset myopia (onset after 15-years-old). The present investigation compared the ocular component dimensions of 30 late onset myopes and 30 emmetropes, who were both age and sex matched. Measurement techniques included A-scan ultrasonography and keratometry. The findings revealed that the ultimate cause of late onset myopia is vitreous chamber elongation. Late onset myopes were also found to have significantly deeper anterior chambers and thinner crystalline lenses, no differences being found in corneal curvature measures. Possible mechanisms leading to these observed biometric differences are discussed in the light of recent findings.
Surgical and Radiologic Anatomy, 2012
Purpose This report assesses white-to-white corneal diameter, pupil diameter, central corneal thickness and thinnest corneal thickness values in a large sample of emmetropic subjects. Methods Three hundred and seventy-nine eyes of 379 young healthy emmetropic subjects were analyzed by means of scanning-slit corneal topography. The age of the subjects ranged from 18 to 53 years (mean ± SD = 29 ± 7). The mean of five consecutive measurements of the central corneal thickness, the thinnest corneal thickness, the whiteto-white corneal diameter, and the photopic pupil diameter was recorded. Results The central corneal thickness ranged from 528 to 588 lm; the thinnest corneal thickness ranged from 504 to 574 lm; the white-to-white corneal diameter ranged from 11.5 to 12.3 mm; and the pupil diameter ranged from 3.0 to 4.7 mm. The central and the thinnest corneal thickness were positively correlated (r = 0.94, p \ 0.001), and the pupil diameter was significantly higher in females (p \ 0.001). Conclusions This study shows that there are no differences in white-to-white corneal diameter, central corneal thickness, and thinnest corneal thickness between emmetropic females and males. However, pupil diameters are greater in emmetropic females.
The Effects of Age, Refractive Status, and Luminance on Pupil Size
Optometry and vision science : official publication of the American Academy of Optometry, 2016
Pupil size is critical for optimal performance of presbyopic contact lenses. Although the effect of luminance is well known, little information is available regarding other contributing factors such as aging and refractive status. The cohort population comprised 304 patients (127 male, 177 female) aged 18 to 78 years. Pupils were photographed at three controlled luminance levels 250, 50, and 2.5 cd/m using an infra-red macro video camera. Measurements of pupil diameter were conducted after transforming pixel values to linear values in millimeters. Luminance was the most influential factor with pupil diameter increasing with decreased luminance (p < 0.001, all comparisons). Age was also found to be a significant factor with a smaller diameter in the older groups, but overall the difference was only significant between the pre-presbyopes and the established presbyopes (p = 0.017). Pupil diameter decreased significantly with increasing age, the effect being most marked at low lumina...
Anisometropia of ocular refractive and biometric measures among 66- to 79-year-old female twins
Acta ophthalmologica, 2016
To examine the prevalence of anisometropia of spherical refraction (AnisoSR), astigmatism (AnisoAST) and spherical equivalent (AnisoSE) and their associations with spherical refraction (SR), refractive astigmatism (AST), spherical equivalent (SE) and interocular differences of ocular biometric parameters among elderly female twins. Refraction of 117 monozygotic (MZ) and 116 dizygotic (DZ) female twin subjects aged 66-79 years was assessed with an auto-refractor (Topcon AT) and controlled by subjective refraction. Corneal refraction, anterior chamber depth and axial length were measured with a Zeiss IOL Master. Participants with eyes operated for cataract or glaucoma were excluded, but the grade of nuclear opacity was not recorded. The associations between the absolute values of AnisoSR, AnisoAST and AnisoSE with SR, AST, SE, corneal refractive power (CR), corneal astigmatism (CAST), anterior chamber depth (ACD) and axial length (AL) and with their interocular differences were calcul...
Axial Length, Corneal Radius, and Age of Myopia Onset
Optometry and Vision Science, 2008
Purpose. This study was designed to establish variations in the biometry of the ocular globe according to refractive state, and to determine the extent to which these characteristics contribute to the appearance and degree of myopia. Methods. Subjects recruited for the study were 583 university students of mean age 20.32 Ϯ 2.82 years. Objective refraction without cycloplegia and the corneal radius (CR) of curvature were determined using an autokeratorefractometer. The axial length (AL) of the eye was measured by ultrasound biometry. The population was then characterized according to these three variables to establish relationships among them. Data were stratified by both refractive state and age of onset of myopia. Results. The prevalence of myopia (more minus than 0.50 D) was 57.78%; half the refractive defects being less minus than Ϫ3.00 D. The AL of the eye was found to be more related to the refractive error than the CR, especially in subjects with moderate myopia. In emmetropes or subjects with low myopia, the CR was directly correlated with AL, although this correlation was somewhat diminished in moderate myopias. Nonetheless, in the latter and in juvenile-onset myopia, a trend towards a shorter radius of curvature was observed. Conclusions. The AL of the eye is the main morphological variable related to myopia. The function of the cornea seems to compensate the possible myopizing effects of slight increases in AL. When increases in AL are excessive, this effect of the cornea tends to disappear.
International Journal of Environmental Research and Public Health
Background: Do gender, age, body mass and height influence eye biometrical properties in young adults? Methods: A total of 155 eyes (92 female, 63 male) of healthy subjects between the ages of 18 and 39 years were included in the study. The subjects’ gender and age were recorded, and their body mass, height and biometrical properties of the eyes were measured. Results: The male subjects had significantly thicker and flatter corneas and lower minimal rim-to-disk ratios than the female subjects did. In both genders, age showed strong, negative correlations with anterior chamber depth and pupil diameter and a positive correlation with lens thickness. We also found significant, negative correlations between body height and mass with keratometry measurements, negative correlations between body height and optic disk rim area and rim volume, and positive correlations between body mass and axial length in both genders. Conclusions: Biometric eye parameters differ among people. In addition t...
Corneal Refraction According to Age and Sex in an Isolated Population and the Heredity of the Trait
Acta Ophthalmologica, 2009
During the nineteenth century it became possible to measure the corneal radius, and particularly after Java1 had constructed his ingenious apparatus, intensive research began in this field. During the first decades of the present century few relevant investigations were made, but today the anterior surface of the cornea again attracts increasing interest as a result of the introduction of contact lenses. With Javal's apparatus the corneal radius can be measured on the living eye with great accuracy, i. e. to the nearest quarter of a dioptre. A large number of statistical studies on the corneal radius and its relationship with total refraction have been published. The majority of authors, beginning with Donders in 1866, have found a sex difference of up to 1.7 per cent of the dioptre value, men having a less refractive cornea than women. Of Finnish investigators, Heinonen (1928) reported a mean value of 43.51 D in girls and 42.93 D in boys, and Elenius & Sopanen's (1963) corresponding values were 43.13 and 42.42 D (r = 7.79 and 7.92 mm, respectively). Steiger (1894) also found that the ratio of flat corneas (up to 42 D) increased from 20.8 per cent in children up to 8 years of age to 24.8 per cenf in the age group 10-16 years and 32.5 per cent in subjects aged from 16 to 88 years. Among school-children aged from 10 to 16 years the corneal refraction averaged 43.15 D for the girls and 42.89 D for the boys, while the mean refraction for women aged from 20 to 88 years was 42.95 D, and the corresponding value for men was 42.35 D. Later (1913), Steiger noted a corneal refraction of 43.36 D for women aged from 40 to 65 years and 43.0 1) for men. In another paper (1907) he reported a study performed on 3000 Aided by a grant from the Sigrid JusClius Stiftelse, Helsingfors.