Abstract
Purpose: :
Early treatment of choroidal melanoma is an essential goal in order to reduce the risk of metastatic spread. Currently available risk factors employed to assess which small melanocytic choroidal lesions should be treated are based on clinical features. The aim of this study was to evaluate whether multifocal ERG and MP-1 microperimetry alterations found in some choroidal melanocytic lesions correlate with the presence of clinical risk factors for growth.
Methods: :
Fifteen patients with choroidal nevi were included in the study. All patients underwent binocular ophthalmoscopy, epilesional OCT and US examination to assess the presence of clinical risk factors. Cone-driven multifocal ERGs were recorded in response to the m-sequence modulation of 61 hexagons presented to the central 30 degrees of the retina. Response amplitude densities (RAD) and implicit times of the first order kernel N1-P1-N2 components were measured. Ring (5 rings between 0 and 25 degrees eccentricity) and sector (nasal, temporal superior and inferior fields) analyses were performed. MP-1 microperimetry was performed using Goldmann III stimuli and a 4-2-1 staircase strategy. The stimuli were projected on the area overlying the melanocytic lesion and on the same area in the controlateral unaffected eye.
Results: :
Seven eyes of seven patients had no risk factors for growth, whereas five eyes of five patients had 1 risk factor for growth and four eyes of four patients presented with 2 risk factors for growth. None of the patients without any risk factor presented mfERG response changes in the sector affected. Four patients (80%) with one risk factor had mfERG response changes and four patients (100%) with two risks factors showed reduced mfERG response amplitudes in the sector affected. On MP-1 microperimetry the light threshold on the retinal area overlying the lesion was comparable to a similar area in the unaffected eye in six out of seven eyes (85.71%) without risk factors, whereas in three out of five eyes (60%) with one risk factor and in four out of four eyes (100%) with two risks factors the sensitivity threshold was remarkably reduced.
Conclusions: :
There is evidence of a correlation between mfERG and MP-1 changes and known clinical features predictive of growth. Multifocal ERG and MP-1 could be of potential value in the decision-making process for treatment providing objective measurements and allowing an exact quantification of melanocytic growth potential.
Keywords: melanocytes • tumors • electroretinography: clinical