Reference Ranges for Fixed Protocol Short Duration Transient Visual Evoked Potentials Parameter of Healthy Eyes

Abstract

 

Purpose

 

To evaluate the responses of Fixed Protocol Short Duration Transient Visual Evoked Potentials (SD-tVEP) on healthy subjects, to obtain the distribution of these parameters, and to establish expected reference ranges.

 

Methods

 

95 healthy eyes were randomly selected (95 subjects). Inclusion criteria was: 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 disk photos, normal retinal nerve fiber layer thickness by optic coherence tomography, normal dilated fundus examination. SD-tVEP’s were recorded using the Diopsys NOVA System . Each eye was stimulated with a 15% (Lc) and 85% (Hc) Michelson contrast checkerboard pattern. Test duration was 30 seconds/eye and each test resulted in a low and high contrast response . Each response’s P100 latency and N75-P100 amplitude was evaluated. Reference ranges were calculated: Lc Amplitude, Lc Latency, Hc Amplitude and Hc Latency. The reference ranges were validated for normal distribution 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: 45.3% male; 54.7% female; 75.8% Caucasian; 2.1% African American; 17.9% Hispanic; and 4.2% Asian. The age range was 21 to 81 years old. Table 1 is the SD-tVEP parameter age adjusted reference ranges with ±95% CI.

 

Conclusions

 

SD-tVEP low and high contrast fixed protocol reference ranges with (-/95%CI) will provide the clinician the ability to compare a patient’s SD-tVEP results to an age adjusted mean value with upper and lower limits.  

 

Table 1. SD-tVEP parameter age adjusted reference ranges with ±95%CI.