Images of Lisch nodules across the spectrum.

The presence of melanocytic hamartomas on the iris, known eponymously as Lisch nodules, is highly characteristic of neurofibromatosis type 1 (NF1). Early recognition of NF1 is vital for optimal detection of associated tumours and for genetic counselling of family members. Although the iris nodules are probably not visible at birth, their prevalence in patients with NF1 gradually increases from birth to about 50% of 5-year-olds, 75% of 15-year-olds and 95-100% of adults over the age of 30. Iris hamartomas in NF1 are elevated, pale brown lesions that vary in appearance depending on the underlying colour of the iris. Colour illustrations are shown in this article, enabling the clinician readily to differentiate hamartomas from other iris lesions.