Iris freckles may suggest sun damage on skin
Iris freckles are good indicators of sun exposure and may be accessible markers in assessing sun damage on the skin, a new study suggests.
The study included 632 participants (mean age 38.4±18.4 years; 57 percent female) being screened for skin cancer. Only those able to undergo slit lamp examination were included. Baseline demographic data and information on sun exposure was collected via anonymous questionnaires.
Following dermatologic examination, slit lamp examination was performed to determine the presence, number and location of iris freckles, which are characterized by small flecks of pigment on the anterior surface of the iris.
At least one iris freckle was observed in 76.1 percent (n=481) of the participants. The median number of iris freckles was five (one to 70). Freckles occurred bilaterally in majority of the participants (72.6 percent; n=349), while 13.3 (n=64) and 14.1 (n=68) percent had unilateral freckles on the right and left sides, respectively.
The presence of iris freckles was associated with a significantly higher number of sunburns (p<0.001), less use of sun protection (p=0.034) and more history of severe sunburns with blisters (p=0.034).
Moreover, significantly less participants with iris freckles had no actinic lentigines (p<0.001), more had sun-damaged skin (p<0.001) and more had freckles on the skin (p<0.001). Iris freckles also showed a significant relationship with a high number of melanocytic nevi on the skin (p=0.027).
“The evaluation of iris freckles offers an easily accessible potential biomarker that might be helpful in indicating chronic sun exposure. Therefore, the evaluation of iris freckles could be helpful in understanding the role of sunlight in several ophthalmologic diseases,” said the researchers.