Elsevier

Ophthalmology

Volume 105, Issue 8, 1 August 1998, Pages 1359-1363
Ophthalmology

Iris color, skin sun sensitivity, and age-related maculopathy: The blue mountains eye study

https://doi.org/10.1016/S0161-6420(98)98013-7Get rights and content

Abstract

Objective

The purpose of the study was to assess relationships between age-related maculopathy (ARM) and iris color, skin sun sensitivity, and other sunlight-related factors.

Design

Cross-sectional population-based study.

Participants

The Blue Mountains Eye Study performed a detailed eye examination of 3654 residents living in the Blue Mountains area, west of Sydney, Australia.

Main outcome measures

Subjects with late age-related macular degeneration (late AMD), early ARM, and large drusen (≥125 μm diameter) were identified using masked grading of retinal photographs. Iris color was graded using standard photographs, and interviewers collected questionnaire data on sunlight-related factors. Logistic regression, adjusting for age, sex, AMD family history, and current smoking, was used to assess associations.

Results

Blue iris color was significantly associated with an increased risk of both late AMD (odds ratio [OR], 1.69) and early ARM (OR, 1.45). An increased risk of late AMD, but not early ARM, was associated with both high (OR, 2.54) and low (OR, 2.18) skin sun sensitivity, as assessed using the Fitzpatrick sun-sensitivity scale. These associations remained after adjusting for the presence of sun-related skin damage. Neither history (or treatment) of skin cancer lesions, signs of sun-induced skin damage, or number of severe sunburns was associated with either late AMD or early ARM.

Conclusions

Blue iris color was associated with an increased risk of both late AMD and early ARM in this population. Abnormal skin sensitivity to sunlight was also associated with an increased risk of late AMD.

Section snippets

Methods

The Blue Mountains Eye Study (BMES) is a population-based survey of vision and eye disease in an urban population aged 49 years or older, resident in two postcode areas in the Blue Mountains region, west of Sydney, Australia. Details of the survey methods have been previously described.2, 15, 16 Of the 4433 eligible residents, 3654 (82.4%) were examined during 1992–1994. A questionnaire covering medical history was administered, and subjects underwent a detailed eye examination, including

Results

The distributions of iris, hair, and skin color, skin sun sensitivity, number of bad sunburns, and examiner-assessed skin damage in women and men are shown in Table 2. Associations between iris, hair, and skin color and each outcome: (1) late AMD, (2) neovascular AMD, (3) early ARM, and (4) large drusen are shown in Table 3. This analysis revealed a significantly reduced risk for both late AMD and early ARM for other iris colors combined compared with blue, with no particular iris color

Discussion

Iris color was associated with both late AMD and early ARM, with blue-eyed subjects at higher risk of having late AMD or early ARM than subjects with all other iris colors, either individually or combined. This result is consistent with findings by Hyman et al,3 Holz et al,5 and Weiter et al,4 although no significant iris color association was found in the other five studies examining this hypothesis. A biologically plausible explanation for the lower risk of ARM among subjects with nonblue

Conclusions

This study provides further evidence that blue iris color is associated with an increased risk for both early ARM and late AMD. However, recent observations regarding change in iris color during life5, 29 and ARM were not able to be tested. Skin sensitivity to sunlight was also found to be associated with an increased risk of late AMD but not with early ARM. No other markers of sunlight exposure, from the history or examination, were found to be associated with age-related maculopathy.

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