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Buck Cunningham, Thomas Callan, Carmen Yoo, Sophia Yu; Pupil Size Over Course of Perimetry Exam – Influence of Translucent and Opaque Occlusion. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2841.
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© ARVO (1962-2015); The Authors (2016-present)
Currently pupil size is determined once at the beginning of a perimetry test on the Humphrey Field Analyzer (HFA). However, pupil size has been observed to change during the course of the test. The purpose of this study was to record and analyze pupil size measurements using a standardized threshold visual field test (24-2 SITA-Standard) with a high speed camera. Data was collected on subjects taking visual field examinations using both translucent and opaque eye patches over the occluded eye.
Volunteers with no known ophthalmic diseases were recruited and both eyes were tested with the Swedish Interactive Thresholding Algorithm (SITA) Standard 24-2 test using an opaque (black) eye patch and a translucent (white) eye patch on the HFA3 Model 860 (ZEISS, Dublin, CA). Each eye of each subject was tested once with each eye patch for a total of four tests per subject. Pupil size was measured by the HFA at the start of each test. During the tests, the pupil size was continuously recorded every 100ms, using the new HFA3 eye image processing capability. Mean and standard deviation of pupil size as a function of time though the course of the visual field test were calculated.
Ten normal subjects (mean age 46.5; range 31 – 63 years) were studied. Mean pupil size using translucent (W) occlusion (4.53 mm, SD 1.18) was slightly smaller than with opaque (B) occlusion (4.70 mm, SD 1.27) while the mean pupil size range during the test was slightly larger for white than black (W: 1.91 mm SD 0.61; B: 1.87 mm SD 0.82) but neither was statistically significant ( P= 0.640 and P= 0.854 respectively). The mean value for all pupil size measurements was within 0.5 mm of the initial reported value in 92% of the tests. Range of pupil size variation was from 0.9 mm to 3.4 mm (see Figure 1). Also, the pupil size was within 0.5 mm of the mean for 89% of the test time.
There was no significant difference in pupil size with either opaque or translucent occlusion. Though there is fluctuation of the pupil and a range of pupil size during a visual field test, the initial pupil size recorded by the HFA was within 0.5 mm of the mean size for most of the visual field tests. Also, the pupil size measured within 0.5 mm of the mean for most of the test duration.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
Fig. 1 Examples of small and large range of pupil size changes over time.
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