Abstract
Purpose: :
To investigate the sensitivity and specificity of 4 stimulus variations of multifocal pupillographic perimetry in unilateral exudative macular degeneration (MD).
Methods: :
Pupillary contraction amplitudes and time to peak contraction were analysed for 29 normal (mean age 70.9 ±6.0) and 20 unilateral exudative MD (mean age 78.0 ±5.3) subjects with 4 different stimulus protocols. Stimuli were presented dichoptically and pupil responses were measured concurrently. All protocols presented multifocal stimulus arrays subtending ±15° of visual field. A dart board layout having 24 or 44 independent test regions/eye with a mean presentation interval of 1 or 4 s/region and a presentation duration of 33 ms on each presentation was employed. Luminance of the stimulus regions was 250 cd/m2 and background 10 cd/m2. Test duration was 4 minutes separated into 8 segments of 30 second recording intervals. Cameras under infrared illumination monitored pupil responses. Data during blinks and fixation losses were excluded to a maximum of 15% of responses beyond which a segment was repeated.
Results: :
Stimuli presented in a 24 region layout with a 4 s/region presentation rate achieved the largest responses by a factor of 2.3 (b = 3.63 dB, t = 3.57, p <.00001); however this was not found to be most diagnostic, achieving an ROC area under the curve (AUC) of 83.31%. A linear discriminant model incorporating contraction amplitude and time to peak found the 44 region layout with 4 s/region presentation rate to be the most diagnostic achieving an AUC of 89.51%.
Conclusions: :
The clinical application of multifocal pupillography utilizing a 44 region stimulus with a slow presentation rate can produce ROC AUC of 89% in the diagnosis of unilateral exudative MD. Further investigation into the assessment of non-exudative MD through pupillography may facilitate early diagnosis and therapeutic intervention.
Keywords: age-related macular degeneration • pupil • perimetry