CORTICAL LENTICULAR OPACIFICATION - DISTRIBUTION AND LOCATION IN A LONGITUDINAL-STUDY

Purpose. To examine the distribution of cortical opacification of the lens by lens quadrant in a longitudinal study. Methods. In 1990, a fol low-up assessment of a cohort of Chesapeake Bap watermen, initially st udied in 1985, was performed. Four hundred thirty-seven subjects (834 eyes) had gradable cortical photographs for at least one eye in both 1 985 and 1990. Cortical photographs were graded by both estimating tota l area and determining the quadrant with the greatest degree of cortic al opacification.Results. The prevalence and severity of cortical opac ification increased with age with a high degree of concordance (84%) b etween eyes. For the 47 eyes with cortical opacification greater than or equal to 1/8 at baseline, the principal locations of opacification were: inferonasal 63.8%, inferotemporal 17.0%, superonasal 6.4%, and s upertemporal 12.8% (P < 0.001, compared with equal distribution by qua drant). Five-year development of new cortical opacification and five-y ear progression of existing cortical opacification showed even greater preferential occurrence in the inferonasal quadrant of the lens. Conc lusions. In this population, the inferonasal quadrant of the lens is t he principal site of cortical opacification in both cross-sectional an d longitudinal assessment. This finding is consistent with the hypothe sis that sunlight exposure is a significant risk factor for cortical o pacification.