Age and Myopia–Related Changes in Multifocal Electroretinography (Mferg) Recorded With Lcd Monitor–Provided System in Normal Subjects

Abstract

 

Purpose:

 

To determine normal values for N₁ and P₁ components of mfERG responses recorded with LCD monitor–based multifocal system in normal subjects of different age groups with and without moderate–to–high myopia.

 

Methods:

 

The study was performed in 52 volunteers divided into four groups. Group A included 16 emmetropes 18–45 y/o; group B – 17 emmetropes 45–75 y/o; group C – 13 myopes 18–45y/o; group D – 6 myopes 45–75y/o. For the recording, VERIS^TM multifocal system (San Mateo, CA) was used and 103–hexagonal element stimulus was employed. Latencies and amplitudes of N₁ and P₁ components were evaluated. For the statistical analysis one way ANOVA with concomitant paired t–test were performed.

 

Results:

 

As compared with the group A, at the 0º eccentricity, mean values for the N₁ amplitude were reduced by 2.26% in group B, by 9.15% in group C, and by 12.9% in group D (p<0.05); mean values for the P₁ amplitude were reduced by 10.65% in group B (p<0.05), by 14.1% in group C (p<0.05), and by 40.8% in group D (p<0.05). At the eccentricities from 5º to 25º, mean values for the N₁ amplitude were reduced by 5.22±3.7% in group B, by 11.54±7% in group C (p<0.05), and by 31.85±5.15% in group D (p<0.01); mean values for the P amplitude were reduced by 0.9–1% in group B, by 19.25±3.3% in group C (p<0.05), and by 22.5±4.5% in group D (p<0.05). The table shows averages (nV) and standard deviations for the P₁ amplitude in groups A–D at different eccentricities: The N₁ and P₁ latencies within the central 10º were not significantly different between the groups; however, at the eccentricities from 15º to 25º there was a significant delay of both N₁ and P₁ in group D as compared with other groups.  

 

Conclusions:

 

Our findings indicate age–related and myopia–related depression of cone function in the posterior pole of the eye. The data can be used as a normative database in the evaluation of retinal function by means of LCD monitor–provided multifocal system in myopic and non–myopic patients of different age groups.

 

Keywords: electrophysiology: clinical • retina • photoreceptors