The role of multifocal electroretinography in the preclinical diagnosis of tumor-associated distant maculopathy in small melanoma of the choroid of extramacular localization

Abstract

To assess the role of multifocal electroretinography (mf-ERG) in preclinical diagnosis of tumor-associated distant maculopathy in small choroidal melanoma (CM) of extramacular localization.Material and methods. 35 patients (35 affected and 35 fellow eyes) with small CM of extramacular localization and 23 healthy volunteers (46 eyes) aged 59.67 ± 14.2 years were given general ophthalmological examinations and mf-ERG. Density (nV/deg2), culmination time of the P1 component and amplitude (μV) of the N1 component were measured for 5 response rings (R1–R5) at different distances from the fixation point: central hexagon R1: 2.3° (fovea zone); R2: 2.3–6.9° (parafovea); R3: 6.9–14.3° (perifovea); R4: 14.3–20.8° and R5: 20.8–29.9° (middle periphery areas of the retina).Results. Eyes affected by CM showed a decrease in the density of the P1 component in the R1 hexagon by 25.7% of the normal values (p = 0.03). The fellow eyes showed an increase in the density of the P1 component in the R2 ring (p < 0.05). The peak latency of the P1 component in the R1–R5 rings in the affected and fellow eye was found to elongate by 30–45% (p < 0.05). The amplitude of the N1 component in the central hexagon of CM-affected eyes increased by 12.96%, whilst in the R4–R5 rings it decreased by 36–45% as compared with healthy individuals (p < 0.05). The fellow eye showed supernormal values of the N1 amplitude in R1 and its suppression in R4 and R5 rings (p < 0.05).Conclusion. The mf-ERG method is useful for preclinical diagnosis of tumor-associated distant maculopathy in small CM of extramacular localization. Changes in mf-ERG of the fellow eye in patients with small CM have been documented.