Diagnostic Value of a Non-Invasive Protocol for Focal and Pattern ERG Recordings in Children With Macular and Optic Nerve Dysfunctions

Abstract

Purpose: : To evaluate the diagnostic value of a non-invasive protocol for focal and pattern electroretinogram (FERG and PERG, respectively) recordings in children suffering from macular and optic nerve dysfunctions

Methods: : FERGs to 32 Hz flicker and PERGs to 8 Hz, 1.7 cycles/degree sinusoidal gratings, presented to the macular region (central 9 degrees), were recorded by skin electrodes in children (5 to 10 year old) with a clinically-established diagnosis of cone dystrophy (n = 15) or optic neuropathy (n = 15, inflammatory, compressive or traumatic). In both diagnostic groups visual acuity was comparable (Snellen equivalent: 0.4, range: 0.3-0.7). An age-similar control group of normal children (n = 15) was also tested.

Results: : In children with cone dystrophy, both FERGs and PERGs were reduced (p < 0.01) in amplitude and delayed in phase, compared to control values. In children with optic neuropathy, FERG amplitude was normal while PERG was reduced (p < 0.01) in amplitude compared to control values. In individual children, combined analysis of FERG and PERG responses correctly identified 100% of cone dystrophy (having both FERG and PERG abnormal) or optic neuropathy (having normal FERG and abnormal PERG) diagnoses.

Conclusions: : The current, non-invasive protocol for FERG and PERG recordings proved to be of diagnostic value, in a pediatric patient population, for discriminating primary macula from optic nerve dysfunctions

Keywords: electroretinography: clinical • macula/fovea • neuro-ophthalmology: diagnosis