Brown eyes are more likely to develop iris melanoma

Patients with brown irises are most likely to develop melanomas, according to recent study results published in the Archives of Ophthalmology.

The investigation, led by Dr Samira Khan, New York University School of Medicine, New York, USA, conducted a retrospective chart review on 131 iris melanoma patients from eight eye cancer centres across six countries.

Internet-assisted multicentre, privacy-protected on-line data entry was possible due to the creation of a computer program. Patient and tumour characteristics, ocular and angle abnormalities, management, histopathology and outcomes were among the factors included in the statistical analysis.

Of the patients studied, 65.6% had brown irises, 62.2% had blue-grey, 29.1% had green-hazel, 9.9% had amelanotic and 6.9% had multicoloured irises.

Patients experienced a variety of disorders including iritis, glaucoma, hyphaema and sector cataract. The results of high-frequency ultrasonograpy presented a largest mean tumour diameter of 4.9 mm, a mean maximum tumor thickness of 1.9 mm, angle blunting in 52% of patients, iris root disinsertion in 9% and posterior iris pigment epithelium displacement in 9%.

The American Joint Commission on Cancer-Internaional Union Against Cancer Classification was used to identify T1 tumours in 56% of patients, T2 tumours in 34%, T3 tumours in 2% and T4 tumours in 1%.

At five years the Kaplan-Meier analysis demonstrated a 10.7% risk of metastatic melanoma. The histopathologic grades were G1-spindle in 54% of patients, G2-mixed in 28%, G3-epithelioid in 5%, and undetermined in 13% of cell types.

The iris melanomas were commonly found in the inferior quadrants of patients with light irides. Angle blunting and spindle cell histopathology are linked to small and unifocal melanomas.