BACKGROUND: To assess the influence of natural and pharmacologically induced pupil size fluctuations on differential luminance sensitivity threshold (DLS) using bright (increment) and dark (decrement) stimuli. METHODS: Twelve healthy volunteers (20-30 years) were examined under the effect of phenylephrine 2%, dapiprazole 0.5%, and placebo. Pupil size was recorded by infra-red video camera in sessions without and with visual field examination (Tübingen Computer Campimeter). DLS was estimated at 9 locations within the central 20 degrees visual field, using bright and dark 26 min-of-arc-stimuli (10 cd/m(2) background, 4-2-1 dB thresholding strategy, four reversals). RESULTS: There were substantial inter-individual differences in pupil size and pupil size fluctuations. Intra-individual differences were small. Independently of medication, pupil size fluctuations were reduced by more than one-third when a subject was undergoing perimetric examination. Pupil size affected DLS on its own (slope 0.21 dB/mm; 95% CI: 0.09-0.33 dB/mm), differently at different stimulus locations, and to a greater extent with increment than with decrement stimuli (slope difference 0.13 dB/mm; 95% CI: 0.00-0.26 dB/mm). CONCLUSIONS: Campimetric examinations have a stabilising effect on pupil size fluctuations. Pupil size affects DLS with bright stimuli more than with dark stimuli; in normal young subjects this effect is not relevant for clinical or normative studies.
BACKGROUND: To assess the influence of natural and pharmacologically induced pupil size fluctuations on differential luminance sensitivity threshold (DLS) using bright (increment) and dark (decrement) stimuli. METHODS: Twelve healthy volunteers (20-30 years) were examined under the effect of phenylephrine 2%, dapiprazole 0.5%, and placebo. Pupil size was recorded by infra-red video camera in sessions without and with visual field examination (Tübingen Computer Campimeter). DLS was estimated at 9 locations within the central 20 degrees visual field, using bright and dark 26 min-of-arc-stimuli (10 cd/m(2) background, 4-2-1 dB thresholding strategy, four reversals). RESULTS: There were substantial inter-individual differences in pupil size and pupil size fluctuations. Intra-individual differences were small. Independently of medication, pupil size fluctuations were reduced by more than one-third when a subject was undergoing perimetric examination. Pupil size affected DLS on its own (slope 0.21 dB/mm; 95% CI: 0.09-0.33 dB/mm), differently at different stimulus locations, and to a greater extent with increment than with decrement stimuli (slope difference 0.13 dB/mm; 95% CI: 0.00-0.26 dB/mm). CONCLUSIONS: Campimetric examinations have a stabilising effect on pupil size fluctuations. Pupil size affects DLS with bright stimuli more than with dark stimuli; in normal young subjects this effect is not relevant for clinical or normative studies.
Authors: S Lutz; T J Dietrich; N Benda; B Selig; H Strasburger; U Schiefer Journal: Graefes Arch Clin Exp Ophthalmol Date: 2001-03 Impact factor: 3.117
Authors: Sarwat Salim; Kevin Childers; Alvaro P C Lupinacci; George Z Hu; Vance Zemon; Peter A Netland Journal: Doc Ophthalmol Date: 2010-02-10 Impact factor: 2.379