Steady-State Pattern Electroretinogram (ssPERG) Fixed Protocol Reference Ranges of Healthy Eyes.

Abstract

 

Purpose

 

To establish reference ranges from healthy subjects for the Steady State Pattern Electroretinogram (ssPERG) Fixed Protocols responses.

 

Methods

 

60 healthy eyes (60 subjects) were randomly selected. Inclusion criteria were the following: best corrected visual acuity 20/30 or better, spherical refraction within ±5.00 D, cylinder correction within ±3.00 D, normal Standard Automated Perimetry, normal slit lamp biomicroscopy, intraocular pressure ≤22 mmHg, normal stereoscopic disc photos, normal retinal nerve fiber layer (RNFL) thickness by optical coherence tomography (OCT), normal dilated fundus examination. ssPERGs were recorded using the Diopsys NOVA System (Diopsys, Inc. Pine Brook, NJ). Each eye was stimulated with the contrast sensitivity and the concentric field protocols. Test duration was 30 seconds/eye and each test resulted in a magnitude and magnitudeD response. Each response’s Magnitude, MagnitudeD and the MagnitudeD/Magnitude ratio was evaluated. Reference ranges were calculated for the Magnitude and MagnitudeD parameters for both protocols. The reference ranges were validated for normality of the residuals (Observed values - Predicted values) across the entire age range and for three equal sized subgroups based on age.

 

Results

 

Study population demographics were: 31.7% male; 68.3% female; 65.0% Caucasian; 10.0% African American; 10.0% Hispanic; and 15.0% Asian. The age range was 25 to 86 years old. The Magnitude was not significantly affected by the age (p=0.098). However, age did have an effect on the MagnitudeD parameter (p=0.004). The reference ranges with ±95% CI are as follows: Magnitude (Predicted) = 1.604 - 0.006 * Age, Magnitude (±95% CI) = 1.604 - 0.006 * Age (±1.96 * 0.39, MagnitudeD (Predicted) = 1.615 - 0.012 * Age, Magnitude (±95% CI) = 1.615 - 0.012 * Age (±1.96 * 0.43.

 

Conclusions

 

The ssPERG fixed protocol reference ranges with (±95CI) will provide researchers and clinicians the ability to compare a healthy subject or patient’s ssPERG results to an age adjusted mean value.