Pinholes and presbyopia: solution or sideshow?

Charman, W. N.

doi:10.1111/opo.12594

Cited by 21 publications

(29 citation statements)

References 71 publications

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“…The lens is based on the well-established optical principles of a pinhole, which prevents the peripheral light rays from entering the eye and minimizes the effects of optical aberrations, increasing the visual quality and depth of focus. 27 As a supplementary lens, the Xtrafocus lens also has specific features to prevent complications related to piggyback IOLs, which were elaborated in detail in a previous study. 28 …”

Section: Discussionmentioning

confidence: 99%

A pinhole implant to correct postoperative residual refractive error in an RK cataract patient

Son

Khoramnia

Mayer

et al. 2020

American Journal of Ophthalmology Case Reports

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Purpose To report the clinical outcomes after implantation of a pinhole supplementary implant (Xtrafocus, Morcher GmbH, Stuttgart, Germany) to correct fluctuating residual refraction after cataract surgery in a patient with a history of radial keratotomy (RK). Observations A 62-year-old patient who had radial keratotomy 22 years earlier, underwent uneventful bilateral cataract surgery using the ASCRS IOL-Calculator for post-RK. Postoperatively, the patient showed fluctuating subjective manifest refraction (MR) on both eyes. To correct the large fluctuating residual refractive error and subjectively worse visual acuity, Xtrafocus IOL was implanted in the right eye. One week later, the uncorrected distance visual acuity (UDVA) was already 0.1 logMAR and the patient stated to have stable vision. Three months after Xtrafocus implantation, the UDVA was −0.04 logMAR which did not improve with MR and the patient expressed high satisfaction, good subjective binocular contrast sensitivity, comparable visual field outcomes, and an elongated depth of focus. Conclusions and Importance The pinhole sulcus implant not only helped eliminate the fluctuation in residual refraction after cataract surgery, but also provided an elongated depth of focus without greatly affecting the visual field. The supplementary implantation of the Xtrafocus lens can offer an effective option for the treatment of instable refractive errors after cataract surgery in patients with a history of corneal surgery.

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Section: Discussionmentioning

confidence: 99%

A pinhole implant to correct postoperative residual refractive error in an RK cataract patient

Son

Khoramnia

Mayer

et al. 2020

American Journal of Ophthalmology Case Reports

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“…Balancing the need for expanded depth of field with the need to avoid loss of distance vision may require a small pupil approach that adjusts with light level, and this behaviour is generally observed with miotics drugs . As pointed out by Charman, effectiveness of expanding the eye's depth of field may also be enhanced if the eye is slightly myopic.…”

Section: Small Aperture Opticsmentioning

confidence: 99%

“…The need for multiple optical powers can be avoided by employing pinhole optics, which can expand the depth of field of the eye 21,40,41 because the blur resulting from defocus is approximately proportional to pupil diameter. 42 The invertebrate nautilus employs this type of pinhole eye design, achieving imaging and depth of field with a small pupil, 14 and to a lesser extent, there is some argument that human vision also employs this small pupil strategy.…”

Section: Small Aperture Opticsmentioning

confidence: 99%

“…Clinical strategies that employ pinhole pupils to expand the eye's depth of field have a long history (for example, Daza de Valdes, 1591, cited in a recent review by Charman 21 ). Three key parameters must be selected: pupil axial location, pupil size, and whether to employ a fixed pupil or one that varies with light level.…”

Section: Small Aperture Opticsmentioning

confidence: 99%

“…Variants of these less common strategies are now being utilised by older humans who have lost the ability to adjust power of their lenses (presbyopes and pseudphakes 17,18 ), a senescent trait also observed in non-human primates and other mammals. 18,19 This paper builds upon recent comprehensive reviews 20,21 to examine the optical implications of current and potential strategies to focus the retinal image despite the loss of accommodative ability.…”

mentioning

confidence: 99%

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Correction of presbyopia: old problems with old (and new) solutions

Kollbaum

Bradley

2020

Clinical and Experimental Optometry

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We live in a three‐dimensional world and the human eye can focus images from a wide range of distances by adjusting the power of the eye's lens (accommodation). Progressive senescent changes in the lens ultimately lead to a complete loss of this ability by about age 50, which then requires alternative strategies to generate high‐quality retinal images for far and close viewing distances. This review paper highlights the biomimetic properties and underlying optical mechanisms of induced anisometropia, small apertures, dynamic lenses, and multi‐optic lenses in ameliorating the visual consequences of presbyopia. Specifically, the advantages and consequences of non‐liner neural summation leveraged in monovision treatments are reviewed. Additionally, the value of a small pupil is quantified, and the impact of pinhole pupil location and their effects on neural sensitivity are examined. Different strategies of generating multifocal optics are also examined, and specifically the interaction between ocular and contact or intraocular lens aberrations and their effect on resulting image quality are simulated. Interestingly, most of the novel strategies for aiding presbyopic and pseudophakic eyes (for example, monovision, multifocality, pinhole pupils) have emerged naturally via evolution in a range of species.

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