Normal value of Arden index:
Ans. d. More than 185% (Ref: Kanski 7/e p649)Normal value of Arden index is more than 185 %.'As there is much variation in EOG amplitude in normal subjects, the result is calculated by dividing the maximal height of the potential in the light (light peak) by the minimal height of the potential in the dark (dark trough). This is expressed as a ratio (Arden ratio) or as a percentage. The normal value is over 1.85 or 185%.' - Kanski 7/e p649Electro-oculographyPrincipleInterpretation* The electro-oculogram (EOG) measures the standing potential between the electrically positive cornea and die electrically negative back of the eye.* It reflects the activity of the RPE and the photoreceptors.* This means that an eye blinded by lesions proximal to the photoreceptors will have a normal EOG.* In general diffuse or widespread disease of the RPE is needed to significantly affect the response.* As there is much variation in EOG amplitude in normal subjects, the result is calculated by dividing the maximal height of the potential in the light (light peak) by the minimal height of the potential in the dark (dark trough).* This is expressed as a ratio (Arden ratio) or as a percentage.* The normal value is over 1.85 or 185%.
1
1.5
Less than 185%
More than 185%
Neuro-Ophthalmology