Biometry and visual function of a healthy cohort in Leipzig, Germany

Abstract

Background: Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany.

Methods: Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies.

Results: The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL -0.19 (0.006), ACD -0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (-0.66 (< 0.001)), ACD (-0.52 (< 0.001)) and ACV (-0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = -0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF -0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age.

Conclusion: Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research.

Trial registration: ClinicalTrials.gov # NCT01173614 July 28, 2010.

Keywords: Cross section; Dioptric distance; Gullstrand; Ocular biometry; Visual function.

Figures

Fig. 1

“Spherical equivalent by age of subject (n = 218)”. Caption: Scatterplot of age and spherical equivalent for subjective refraction. In the study population there was weak association between age and subjective refractive error (r = 0.335, p < 0.001). Regression equation: Spherical equivalent = −3.03 + 0.054 Age; 50 % confidence interval: 1.96 D

Fig. 2

“Contrast sensitivity measured with the Visual Contrast Test System chart and its association with age”. Caption: Contrast sensitivity for all age groups: ● 20–29 years; x 30–39 years; □ 40–49 years; + 50–50 years; ∆ 60–69 years. Gratings examined consisted of spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree

Fig. 3

“Contrast sensitivity results for different spatial frequencies stratefied by refractive status”. Caption: Contrast sensitivity for the three refractive states, stratified by spherical equivalent of subjective refraction determined by best corrected visual acuity: ● myopia; x emmetropia; □hyperopia. Gratings examined consisted of spatial frequencies of 1.5, 3, 6, 12 and 18 cycles per degree