To understand mechanisms of binocular vision from a pathological viewpoint, diseases with abnormal binocular vision, their clinical diagnosis and treatment are reviewed. Strabismus and/or limitation of eye movement induce diplopia and prevent depth perception, due to binocular disparities. Diplopia may disappear with time by way of sensory adaptation, such as suppression in the deviated eye or abnormal retinal correspondence, but this does not necessarily imply recovery from abnormal binocular vision. Strabismus surgery to correct misalignment of the eyes usually reestablishes binocular vision. However, even if the surgery is successful, high-grade stereopsis cannot be achieved in patients with congenital strabismus who have grown up without the experience of binocular vision during the critical period of stereopsis development.
Purpose: To propose new indices of pupil perimetry, indicating inter-individual variability and intra-individual deviation.
Methods: Pupillary light reflex was measured in 57 young normal subjects (mean age: 20.2 ± 1.1 years). The light stimuli were supplied from 21 stimulation points (on the visual field meridians of 45, 135, 225, 315 degrees direction, each of which had 0, 5, 10, 15, 20, 25 degrees); percent pupil contraction was then computed. Regarding inter-individual variability, we proposed summarized percent pupil contraction, quantifying the individually representative response. Regarding intraindividual deviation, we proposed percent pupil contraction deviation, quantifying the roughness of pupillary responses between stimulation points.
Results: Percent pupil contraction monotonically decreased as eccentricity from the center of visual field increased. Correlation analysis showed bilateral symmetry in percent pupil contraction, summarized percent pupil contraction (left eyes 20.8 ± 6.0%, right eyes 20.3 ± 5.8%), percent pupil contraction deviation (left eyes 2.3 ± 0.9, right eyes 2.3 ± 0.7), also showing an inter-independent relationship between summarized percent pupil contraction and percent pupil contraction deviation.
Conclusions: We propose a method for assessing pupil perimetry with doubled size of measurements, offering potential for two-dimensional assessment in clinical ophthalmology.