Models for the description of angioscotomas

To describe small scotomas in visual field examinations several statistical models are proposed and applied to the evaluation of angioscotoma in 13 op hthalmologically normal subjects. A special perimetric grid is used where t hresholds can be estimated along a line of narrow-spaced test points which crosses the predicted location of the retinal vessel. A two-stage analysis employs single estimations to fit a threshold curve by means of a special p arametric description of the luminance difference sensitivity threshold as a function of stimulus position. An alternative model incorporates the thre shold as a function of position into the probabilistic description of the b inary response (stimulus seen/not seen). (C) 1999 Elsevier Science Ltd. All rights reserved.