Study of the blood-aqueous barrier in choroidal melanoma

Aqueous flare was used to determine the frequency and amount of blood-aqueous barrier breakdown and correlate it with tumour variables.

Aqueous flare was analysed prospectively by laser flare photometry in 139 consecutive patients seen in the oncology unit for choroidal melanoma. Both eyes of patients were examined with a laser flare cell meter in a standard fashion.

Mean flare difference between healthy and tumour eyes was 3.01 (SD 2.5) photons per millisecond (ph/ms) in 32 cases of small melanomas (p < 0.0001), 10.74 (13.9) ph/ms in 92 cases of medium and large melanomas (p < 0.0001), and 19.23 (11.8) ph/ms in 15 cases of very large melanomas (p < 0.0001). This mean differential flare was significantly higher in medium and large than in small melanomas (p < 0.002) and in very large melanomas than in medium and large melanomas (p < 0.028). A difference of > or = 7 ph/ms between affected and healthy eyes was noted in 70 of 139 melanomas (50.4%). It was found in 3/32 small melanomas (9.4%), in 53/92 medium and large melanomas (57.6%), and in 14/15 very large melanomas (93.3%).

Multiple linear regression analysis showed that flare was most strongly correlated with tumour volume (r = 0.43; p < 0.0001) and tumour height (r = 0.41; p < 0.0008).