J Korean Ophthalmol Soc.  1995 Mar;36(3):473-478.

Naka-Rushton Equation Parameters in Normal Pigmented Rabbit ERG

• Chung KH
• Kim JH
• Kim SH

Abstract

The Naka-Rushton equation, R=R(max) I(n)/(I(n)+K(n)), has been used to describe the luminance-response function of the scotopic electroretinogram. R(max) is the asymptotic value of the b-wave amplitude as a function of stimulus luminance, K is the intensity that produces a b-wave amplitude that is one-half R(max) and n is a dimensionless contant that controls the slope of the function and represents the degree of homogeneity of retinal sensitivity. These three parameters are often used in experimental laboratories, since it can show selective changes in each parameter. The present study describes and compares the parameters of Naka-Rushton equation obtained by using ganzfeld stimuli(R(max)=363+/-32 uv, n=0.86+/-0.06, log K=-2.39+/-0.19 log cd.sec/m2) and direct flash stimuli(R(max)=354+/-28 uv, n=0.80+/-0.06, log K=-2.26+/-0.15 log cd.sec/m2) in 20 eyes of the normal pigmented rabbits respectively. The n values were significantly increased by the ganzfeld light stimuli than by the direct flash stimuli(p<0.05).

Keyword

Ganzfeld stimulus; Naka-Rushton equation parameters; Rabbit ERG

MeSH Terms

Rabbits
Retinaldehyde
Retinaldehyde