Abstract
Purpose :
The outer limits of the far peripheral visual field have not been formally measured with modern perimeters. Such measurements may be useful to investigate pseudophakic dysphotopsia after intra-ocular lens implantation, and to characterize retinal and optic nerve conditions that affect far peripheral vision. We describe measurements with a modified projection perimeter in a group of healthy observers.
Methods :
Far peripheral visual field measurements were obtained in a group of 16 healthy observers (median age 25 y; range 19 to 44 y). An Octopus 900 perimeter (Haag Streit, Switzerland), controlled through the Open Perimetry Interface (Turpin et al., 2012) was modified with a device that projected a fixation target to 5 eccentric positions such that far peripheral isopters beyond 90° could be measured within a mid-peripheral area of the bowl. Kinetic stimuli of 3 sizes (Goldmann I-4e, III-4e, V-4e) were presented along 9 meridians, at a speed of 5°/s. At each meridian, the median of 3 responses was used to define the isopter.
Results :
The temporal visual field to the Goldmann V-4e stimulus extends to ~100° (Table 1). The precision of the isopter locations, derived from the scatter of individual responses, was best with V-4e (median, 1.2°; range 0.7° to 2.1°) and worst with I-4e (median, 1.6°; range, 0.8° to 3.2°).
Conclusions :
Precise measurements of the extreme limits of peripheral vision, beyond 90° of fixation, are feasible with a simple modification of projection perimeters. Our findings on the limits of peripheral vision are in close agreement with those obtained by Rønne (1915) on a Bjerrum screen.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.