Abstract
Purpose: :
: To investigate the effect of protection from sunlight on lens light scattering profile in a subset of nuns from the Irish Nun Eye Study (INES) correlated to age and outdoor activity / convent type.
Methods: :
After obtaining informed consent, the eyes of 144 retired nuns from contemplative and missionary orders in Ireland were monitored with a Scheimpflug Camera (Pentacam HR®, Oculus, Wetzlar, Germany). Following pupil dilation with tropicamide, Scheimpflug images of the anterior eye segments in 25 meridians were recorded using the automatic recording algorithm of the camera. The images were later subjected to densitometric image analysis using special analytical software (BIOM®). In addition discoloration of the lenses was determined with the handheld slitlamp microscope and LOCS III Grading System. Cortical and posterior sub-capsular lens opacities were also imaged using the Neitz cataract screener. The data were compared to results from other studies investigating lens light scattering and discoloration.
Results: :
Age-related light scattering increase in the nuclear layers of the lenses was generally lower than that of the cortical layers. In addition the frequency of cortical cataracts of various types was significantly higher than that of nuclear cataracts compared to other studies with normal and high light exposure. Lens discoloration intensity proved to be uncorrelated to the intensity of light scattering in distinct lens layers and also not correlated to the amount of light exposure.
Conclusions: :
Light protection affects the intensity distribution of back scattered light in different lens layers and reverses the frequencies of cataract between cortex and nucleus. It does not affect, however, the development of yellow discoloration of the lens.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • cataract • aging