Comparative Analysis of Unaided Emmetropic and Unaided Noncorrected Myopic Underwater Visual Acuity

Cramer, John L.

doi:10.1080/10671315.1975.10615310

Cited by 1 publication

(3 citation statements)

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“…Luria and Kinney (1969) found mean grating resolution loss for 15 emmetropes of 1.0 logMAR at 0.81 m water thickness, similar to that found here. Cramer (1971) determined mean vision acuity underwater for a Landolt C target of 2.3 logMAR, similar to what we found for the large pupil sizes likely to occur under the low lighting conditions of Cramer's study. Gislén et al (2003) attributed the two times better water vision of Moken children than of European children at a grating task (6.1 compared with 3.0 c/8) to the ability of the former to accommodate and reduce pupil size.…”

Section: Discussionmentioning

confidence: 72%

“…The nature of the tasks would be important to this, including that Luria and Kinney's (1969) study was conducted in daylight, which provided the target illumination, and Cramer's (1971) study was conducted at night with lamps illuminating the target. The likely lower ambient lighting levels for the second study and the consequent larger pupils should have contributed to poorer vision.…”

Section: Introductionmentioning

confidence: 99%

“…Across the emmetropes, six myopes, and two hyperopes, resolution in water was 1.07 6 0.13 logMAR. Cramer (1971) determined mean vision underwater for a group of subjects for a Landolt C target to be 2.3 logMAR with significant but small effects of refraction group (myopes 0.04 less logMAR). Participants in the study wore masks containing one of three levels of tonicity of water, but this did not affect results.…”

Section: Introductionmentioning

confidence: 99%

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Vision in water

et al. 2013

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The purpose of this study is to determine visual performance in water, including the influence of pupil size. The water environment was simulated by placing goggles filled with saline in front of the eyes with apertures placed at the front of the goggles. Correction factors were determined for the different magnification under this condition in order to estimate vision in water. Experiments were conducted on letter visual acuity (seven participants), grating resolution (eight participants), and grating contrast sensitivity (one participant). For letter acuity, mean loss of vision in water, compared to corrected vision in air, varied between 1.1 log min of arc resolution (logMAR) for a 1 mm aperture to 2.2 logMAR for a 7 mm aperture. The vision in min of arc was described well by a linear relationship with pupil size. For grating acuity, mean loss varied between 1.1 logMAR for a 2 mm aperture to 1.2 logMAR for a 6 mm aperture. Contrast sensitivity for a 2 mm aperture deteriorated as spatial frequency increased with a 2 log unit loss by 3 c/°. Superimposed on this deterioration were depressions (notches) in sensitivity with the first three notches occurring at 0.45, 0.8, and 1.3 c/° with estimates for water of 0.39, 0.70, and 1.13 c/°. In conclusion, vision in water is poor. It becomes worse as pupil size increases, but the effects are much more marked for letter targets than for grating targets.

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Section: Discussionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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