MO is a 54-year-old woman who noted a shadow increasing over several months in the lower part of her field of vision in the left eye. She presented to her optometrist, who noted vision OD of 20/20 and OS of 20/30 with some distortion. Fundus examination of the left eye found a lightly pigmented lesion posterior to the superior equator. A visual field examination showed an inferior defect that extended into the lower part of central fixation.

B-scan revealed a solid lesion just above the left macula with basal dimension measurements of 6.2 mm circumferentially and 7.1 mm radially with 2+ spontaneous internal vascularity. A-scan measured thickness of the lesion to be 6.24 mm with medium and regular internal reflectivity (Fig. 1).

Fig. 1
figure 00051

A-scan of choroidal melanoma. Tumor surface indicated by first arrow and sclera by second arrow

Full size image

These findings were highly consistent with a choroidal melanoma, and the patient was referred for radioactive plaque therapy after a systemic evaluation for metastatic melanoma was negative.

The quantitative capability of the A-scan has become essential in the management of intraocular tumors. The last 30 years has witnessed the transition from enucleation as the procedure of choice in the management of intraocular malignant melanoma to observation and radiation in cases of documented growth. A-scan measurements of the thickness of intraocular lesions are integral to this current management paradigm.