Pinhole iris-fixated intraocular lens for dysphotopsia and photophobia

Pinhole Pupilloplasty for Higher Order Aberrations: Assessment of Visual Quality and Depth of Focus

PURPOSE

To evaluate visual quality and depth of focus under photopic and mesopic light conditions of patients treated with pinhole pupilloplasty (PPP) for corneal higher order aberrations.

METHODS

This was a prospective, noncomparative, interventional series and PPP was performed with a single-pass four-throw procedure in 14 eyes of 14 patients. After PPP, patients were analyzed with the Clinical Trial Suite machine (M & S Technologies, Inc) that offers a standardized method of recording visual quality. The luminance levels of 85 and 3 cd/m² were set for photopic and mesopic lighting conditions, respectively, and uncorrected and corrected distance visual acuity were recorded for distance (4 m), intermediate (66 cm), and near (44 cm). Low contrast acuity (LCA) at 10% and mesopic contrast sensitivity function (CSF) with glare on and off at four spatial frequencies of 1.5, 3, 6, and 12 cycles per degree (cpd) and defocus curve were assessed.

RESULTS

Under photopic and mesopic conditions, a significant difference was observed postoperatively in uncorrected and corrected distance visual acuity for distance, intermediate, and near. The defocus curve demonstrated extended depth of focus that ranged from +1.50 to -2.50 diopters and LCA at 10% demonstrated significant improvement for all cases. For mesopic CSF, a significant improvement was noted at spatial frequencies of 3 and 6 cpd with glare on. With glare off, an improvement was seen at spatial frequencies of 1.5, 3, and 6 cpd, but not at 12 cpd.

CONCLUSIONS

Early results demonstrate that PPP provides improved visual quality and extended depth of focus and can be a useful option in cases with higher order aberrations. [J Refract Surg. 2020;36(12):812-819.].

Handling regular and irregular astigmatism during cataract surgery

PURPOSE OF REVIEW

There are several different approaches to handling regular and irregular astigmatism during cataract surgery, but still much debate on which solutions are most effective given unique patient circumstances. In this review, we examine recent literature and studies to highlight some of the most effective ways to plan preoperatively, manage regular and irregular astigmatism during cataract surgery, as well as managing postoperative complications.

RECENT FINDINGS

Recent developments in technology have provided increased courses of action for astigmatism management during cataract surgery. Additional options of toric IOLs with presbyopic platforms, light adjustable lenses, intraocular pinhole lenses, online technological tools and platforms, wavefront or topographic laser technology, and phototherapeutic keratectomy are all effective solutions to managing regular and irregular astigmatism. In this review, we will explore optimal approaches for unique situations.

SUMMARY

With increased technology, research, and methods, correcting regular and irregular astigmatism during cataract surgery is achievable in most patients. With in-depth preoperative planning, analysis of patient-specific factors, and a tailored approach, surgeons can obtain excellent uncorrected vision for patients.

Small-aperture optics for the presbyope: do comparable designs of corneal inlays and intraocular lenses provide similar transmittances to the retina?

The near-vision performance of emmetropic presbyopes can be improved by the monocular surgical implantation of small-aperture corneal inlays or intraocular lenses that contain either an annular or circular stop to increase ocular depth of focus. Ray tracing is used to show that, although different stop designs and positions may produce similar axial imagery and increases in depth of focus, off-axis, the vignetting effects associated with the distance between the stop and the iris aperture result in different field dependences for the pupil transmittance. The implications of these effects, and of implanting a stop in only one eye, are discussed.

Presbyopia: Effectiveness of correction strategies

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Reducing starbursts in highly aberrated eyes with pupil miosis

PURPOSE

To test the hypothesis that marginal ray deviations determine perceived starburst sizes, and to explore different strategies for decreasing starburst size in highly aberrated eyes.

METHODS

Perceived size of starburst images and visual acuities were measured psychophysically for eyes with varying levels of spherical aberration, pupil sizes, and defocus. Computationally, we use a polychromatic eye model including the typical levels of higher order aberrations (HOAs) for keratoconic and post-LASIK eyes to quantify the image quality (the visually weighted Strehl ratio derived from the optical transfer function, VSOTF) with different pupil sizes at both photopic and mesopic light levels.

RESULTS

For distance corrected post-LASIK and keratoconic eyes with a night-time pupil (e.g., 7 mm), the starburst diameter is about 1.5 degrees (1 degree for normal presbyopic eyes), which can be reduced to ≤0.25 degrees with pupil sizes ≤3 mm. Starburst size is predicted from the magnitude of the longitudinal spherical aberration. Refracting the eye to focus the pupil margin also removed starbursts, but, unlike small pupils, significantly degraded visual acuity. Reducing pupil diameter to 3 mm improved image quality for these highly aberrated eyes by about 2.7 ×  to 1.7 ×  relative to the natural pupils when light levels were varied from 0.1 to 1000 cd m^-2 , respectively.

CONCLUSION

Subjects with highly aberrated eyes observed larger starbursts around bright lights at night predictable by the deviated marginal rays. These were effectively attenuated by reducing pupil diameters to ≤3 mm, which did not cause a drop in visual acuity or modelled image quality even at mesopic light levels.

Implantation of ArtificialIris, a CustomFlex irisprosthesis, in a trauma patient with an Artisan lens: A case report and review

PURPOSE

To evaluate probable complications of ArtificialIris implantation with iris fixated intraocular lens.

METHOD

Development of photophobia, glare, and psychological strain during face-to-face communication in a 23-year-old man with a widespread traumatic iris defect terminate to make a decision for performing implantation of an ArtificialIris (Humanoptics, Erlangen, Germany) under the remnant iris without removing the patient's existing Artisan lens.

RESULTS

Without any intraoperative or postoperative complications, the patient's visual acuity increased by 1 line, the endothelial cell loss was comparable with the cell loss associated with standard cataract surgery, and the anterior-chamber depth and anterior-chamber anatomy did not change. At the final follow-up examination, the mean intraocular pressure did not differ from baseline, and we achieved high level of patient satisfaction and subjective vision improvement. We discuss the particular importance of considering the patient's expectations, the appropriate measurements, ways to perfect color evaluation, and the types of ArtificialIris products.

CONCLUSION

The implantation of the ArtificialIris in patients with aphakic iris-supported lenses (ie, pre-existing Artisan lenses) is a feasible approach and a useful option for patients with thin irises and iris hypoplasia who are at risk of subluxation or the dislocation of the posterior-chamber intraocular lens (PCIOL), and also those with sclerally fixed PCIOLs.