Retrodots in the Ageing Crystalline Lens in Iceland -Reykjavik Eye Study

Abstract

Abstract: : Purpose: To establish the prevalence of Retrodots (RD) in the Icelandic population 55 years and older. Methods: The Reykjavik Eye Study is a population based study using the population census. The 1045 subjects who participated in The Reykjavik Eye Study (RES) in 1996 were reexamined 5 years later in 2001. 846 or 88% of the survivors participated again in the RES in 2001. Among the 846 participants, 1524 eyes of 762 cases (68.0±8.4 years old) were selected as subjects for the study. Cases with pseudophakic and aphakic eyes were excluded. Changes in the crystalline lens were examined and photographed under maximal pupillary dilation. RD were determined by slitlamp examination and graded in three steps according to the density of RD. Classification of the three main types of opacity was done by photographed images using the simplified cataract classification and grading system established by the World Health Organization (Ophthalmic Epidemiol. 2002). Statistical analysis was performed using logistic regression (Genmod procedure in SAS). Results Prevalence of RD was 19.2% (21.1 % in males and 17.6% in females). We observed 2.9% in 55-59 yrs, 12.0% in 60s, 33.3% in 70s and 40.0% in 80s and over. RD with grade 2 and over increased rapidly after age 70s. RD were observed in 9.8% of the eyes that did not display any of the three main types of opacities. The prevalence of RD in eyes with nuclear, cortical and subcapsular and mixed type of cataract was 26.7%, 22.2%, 12.5% and 37.9%, respectively. Advanced age was risk factor of RD. Further nuclear, cortical and mixed type of cataract were risk factors of RD after adjusting age and gender. Conclusions: The prevalence of RD in the Icelandic population was established. The prevalence of RD increased with aging and was more prevalent in eyes with cortical, nuclear and mixed types of cataract. Since RD is common in the elderly population and often causes visual impairment, not only the three main types of cataract, but also this type of opacity should be further investigated in epidemiological studies.

Keywords: cataract • clinical (human) or epidemiologic studies: pre • clinical (human) or epidemiologic studies: ris