Effect of pupil size on kinetic visual field measurements

Peltre, Gabriel; Kitchen, C.; Brown, Brian

doi:10.1111/j.1444-0938.1988.tb03850.x

Cited by 8 publications

(8 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…I have tried to reconcile the optical predictions in this paper with empirical perimetry findings by other researchers. [3][4][5][6][7][8] Previous researchers have found that semi-opaque periphery contact lenses do not affect field measurements obtained with clinically Contact lens field restriction Carkeet used static perimeters, 6-8 but the optical theory in this paper suggests that such lenses cause the largest retinal illuminance drop for field regions wider than those measured by clinical perimeters. Therefore, future empirical studies of such lenses could involve field regions wider than 60 to 75 degrees.…”

Section: Discussionmentioning

confidence: 76%

“…3 By using kinetic perimetry, it has been shown that such lenses can constrict visual fields 3 but previous literature contains almost no discussion of the optical theory behind the visual field restriction by such lenses. Some authors have measured kinetic visual field restriction with cosmetic contact lenses that have semi-opaque peripheries (that is, a matrix of opaque dots which alter iris colour appearance) 4,5 although two studies have reported that such lenses do not significantly affect static visual fields.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Field restriction and vignetting in contact lenses with opaque peripheries

Carkeet

1998

Clinical and Experimental Optometry

View full text Add to dashboard Cite

BACKGROUND: Some previous researchers have shown empirically that visual fields can be restricted by contact lenses with opaque and semi-opaque peripheral zones. However, there has been no formal statement of the optical theory behind such restriction. METHODS: Calculations are made of fields of view with opaque periphery contact lenses, based on paraxial theory and meridional finite ray tracing in the Gullstrand-Emsley schematic eye. RESULTS: This analysis shows that paraxial theory is adequate for predicting 'half fields of full illumination' for ocular pupil diameters smaller than six millimetres, although paraxial estimates of 'half total field' can substantially underestimate those obtained by finite ray tracing for a wide range of ocular pupil sizes. Therefore finite ray tracing may be a more appropriate method of calculating half total field. 'Total field' will be smaller with smaller ocular pupils and smaller contact lens apertures. A clinical method is suggested for assessing total field with such contact lenses in situ. The analysis applied to opaque periphery contact lenses is extended to the semi-opaque periphery contact lenses used for cosmetic alteration of eye appearance. CONCLUSION: Semi-opaque periphery contact lenses will decrease retinal illuminance most at regions outside those tested by previous empirical static perimetry studies.

show abstract

Section: Discussionmentioning

confidence: 76%

mentioning

confidence: 99%

Field restriction and vignetting in contact lenses with opaque peripheries

Carkeet

1998

Clinical and Experimental Optometry

View full text Add to dashboard Cite

show abstract

“…Figure 5 then suggests that under these conditions the field boundary should lie at field angles of about 60°, which is compatible with the trend of the observed loss in sensitivity at field angles beyond 30° (Figure 7). For comparison, Gabriel et al, 30 using kinetic perimetry and a 31.8 cd m À2 Goldmann I-0.11°stimulus, found that the area of the visual field was limited to about 2.8 steradians in subjects wearing contact lenses with a 3 mm clear aperture, corresponding to a field radius of about 54°.…”

Section: Discussionmentioning

confidence: 99%

Do small‐aperture presbyopic corrections influence the visual field?

Atchison

Blazaki

Suheimat

et al. 2015

Ophthalmic Physiologic Optic

View full text Add to dashboard Cite

Purpose: To explore the effect of small-aperture optics, designed to aid presby-opes by increasing ocular depth-of-focus, on measurements of the visual field. Methods: Simple theoretical and ray-tracing models were used to predict the impact of different designs of small-aperture contact lenses or corneal inlays on the proportion of light passing through natural pupils of various diameters as a function of the direction in the visual field. The left eyes of five healthy volunteers were tested using three afocal, hand-painted opaque soft contact lenses (www.davidthomas.com). Two were opaque over a 10 mm diameter but had central clear circular apertures of 1.5 and 3.0 mm in diameter. The third had an annular opaque zone with inner and outer diameters of 1.5 and 4.0 mm, approximately simulating the geometry of the KAMRA inlay (www.acufocus.com). A fourth, clear lens was used for comparison purposes. Visual fields along the horizontal meridian were evaluated up to 50° eccentricity with static automated perimetry (Medmont M700, stimulus Goldmann-size III; www.medmont.com). Results: According to ray-tracing, the two lenses with the circular apertures were expected to reduce the relative transmittance of the pupil to zero at specific field angles (around 60° for the conditions of the experimental measurements). In contrast , the annular stop had no effect on the absolute field but relative transmit-tance was reduced over the central area of the field, the exact effects depending upon the natural pupil diameter. Experimental results broadly agreed with these theoretical expectations. With the 1.5 and 3.0 mm pupils, only minor losses in sensitivity (around 2 dB) in comparison with the clear-lens case occurred across the central 10° radius of field. Beyond this angle, sensitivity losses increased, to reach about 7 dB at the edge of the measured field (50°). The field results with the annular stop showed at most only a slight loss in sensitivity (≤3 dB) across the measured field. Conclusion: The present theoretical and experimental results support earlier clinical findings that KAMRA-type annular stops, unlike circular artificial pupils, have only minor effects on measurements of the visual field.

show abstract

“…It has since been suggested that it might be useful for presbyopic patients who have already been implanted with multifocal IOLs but who find that their vision is poor. Since the pinhole is very close to the natural pupil, it has negligible effect upon the extent of the visual field although sensitivity is, of course, lost because of the reduced retinal illuminance …”

Section: Surgical Pinhole Variants: Corneal Inlays and Iolsmentioning

confidence: 99%

Pinholes and presbyopia: solution or sideshow?

Charman

2019

Ophthalmic Physiologic Optic

View full text Add to dashboard Cite

Effect of pupil size on kinetic visual field measurements

Cited by 8 publications

References 5 publications

Field restriction and vignetting in contact lenses with opaque peripheries

Field restriction and vignetting in contact lenses with opaque peripheries

Do small‐aperture presbyopic corrections influence the visual field?

Pinholes and presbyopia: solution or sideshow?

Contact Info

Product

Resources

About