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Standard Curve and the Physiological Limits of Dark Adaptation by Means of the Goldmann-Weekers Adaptometer

1956; BMJ; Volume: 40; Issue: 11 Linguagem: Inglês

10.1136/bjo.40.11.652

1468-2079

P. Dieterlé, Elizabeth F. Gordon,

Mental Health Research Topics

UPON passing from light into darkness the light sensitivity of the eye in- creases.This phenomenon is explained by an increase in the sensitivity of the photoreceptor cells of the retina (cones and rods) and is called dark adaptation.First investigated by Aubert (1865), dark adaptation is now studied quantitatively through the dark-adaptation curve: the logarithm of the light threshold (ordinate) is plotted against the time in darkness (abscissa) after pre-adaptation to light under standard conditions.For the last 3 years our dark-adaptation curves have been obtained by means of the Goldmann-Weekers adaptometer.tThis photometric pre- cision instrument is so constructed that the examiner can record the logarithm of the light threshold for a given time of dark adaptation directly on semi- logarithm paper attached to a drum effecting one rotation per hour.Dark- adaptation curves of different normal individuals are never identical and sometimes vary considerably.In order to make a diagnosis of pathological dark adaptation, it is necessary to obtain data obtained under standard conditions to define the range of the physiological variation.The object of this paper is to determine a standard curve (mean curve) and the physiological limits of dark adaptation by means of the Goldmann-Weekers adaptometer.For this purpose we performed a total of twenty dark-adaptation examina- tions (twenty dark-adaptation curves) on a group of twenty normal subjects (including ametropias of from -2 25 to + 3 00 dioptres) whose ages ranged from 12 to 47 years (average 35).TechniqueThe twenty examinations were performed in the following conditions:(1) The pupil is fixed in dilatation (eighteen cases with homatropine, two with neo- synephrine);(2) The examination is monocular;(3) 15 minutes of dark adaptation is given before pre-adaptation to light;