Aging of the human lens: changes in lens shape at zero-diopter accommodation

Abstract

Scheimpflug photographs of the zero-diopter-accommodated anterior segments of 100 human subjects, aged 18 to 70 yr and evenly spaced over this range, were digitized and analyzed to characterize lens and lens nucleus shape as a function of age by the Hough transform and other image analysis methods. Anterior and posterior lens surface curves exhibit a decrease in radius of curvature with increasing age, in qualitative but not quantitative agreement with the earlier observations of Brown [Exp. Eye Res. 19, 175 (1974)]. In contrast, the shape of the lens nuclear boundaries changes little with age. Overall lens volume at zero diopters increases with age, but the volume of the lens nucleus remains unchanged. The lens center of mass moves anteriorly with increasing age, as does the central clear region of the lens. Although these data sets were found to be more variable than those of Brown, the complementary variability of other factors, such as anterior chamber depth, for each subject leads to a very high statistical correlation between lens shape and lens location relative to the cornea. This supports the finding of previous work that image formation on the retina for a given individual results from the multifactorial balancing of related factors.

Intra-session repeatability of iridocorneal angle measurements provided by a Scheimpflug photography-based system in healthy eyes

“…The width of the IA increased with decreasing patient age, which confirms age as a factor influencing the IA, as previous studies have reported [21,22]. The increase in crystalline lens volume with age seems to be crucial in this finding [23]. Likewise, our results suggest that the glaucoma mode evaluated is useful for quantitative evaluation of age-related changes in angle structure in healthy eyes.…”

Aspects of eye accommodation evaluated by finite elements

“…Clinical studies confirm that during accommodation the changes in position and curvature are larger in the anterior Hemenger et al (1995) 19-31 11.21 ± 1.08 6.45 ± 0.56 Phakometry Koretz et al (2001) 29 10.575 7.687 Scheimpflug Dubbelman and Van Der Heijde (2001) 29 11.247 5.852 Scheimpflug Garner and Yap (1997) 19-24 11.54 ± 1.27 6.62 ±0.94 Phakometry Dubbelman et al (2005) 29 11.8 6. It should be noted that in vitro the lens is in a different mechanical state of stress than in vivo.…”

Pentacam Scheimpflug Quantitative Imaging of the Crystalline Lens and Intraocular Lens

“…Although a Scheimpfl ug system could not compete in resolution with anterior segment optical coherence tomography (OCT), 15 which otherwise should also be corrected from optical distortion, 16,17 the large depth of focus in Scheimpfl ug images allows full cross-sections of the anterior segment, from the anterior cornea to the posterior lens, in a single snapshot generally not possible with OCT. Applications of corrected Scheimpfl ug crystalline lens/IOL in vivo imaging include customized eye modeling, 18,19 studies of quantitative changes of crystalline lens morphology with accommodation, 11,[20][21][22] aging, 6,23 or disease, 24 and assessment of new intraocular implants and surgical approaches for the correction of presbyopia. 25 …”