Small-aperture strategies for the correction of presbyopia

BCLA CLEAR Presbyopia: Evaluation and diagnosis

It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.

Applications of the pinhole effect in clinical vision science

The pinhole effect is commonly used to discriminate uncorrected refractive error from ocular diseases. A small aperture limits the width of light beams entering the eye, thus increasing the depth of focus. The pinhole effect has also been used in spectacles, contact lenses, corneal inlays, and intraocular lenses (IOLs) to improve reading by compensating for loss of accommodative function. Pinhole spectacles improve near visual acuity, but reduce reading speed, increase interblink interval, and decrease tear break-up time. For contact lenses and IOLs, pinhole devices are usually used in the nondominant eye, which allow compensation of various refractive errors and decrease spectacle dependence. Pinhole corneal inlays are implanted during laser in situ keratomileusis or as a separate procedure. Pinhole IOLs are gaining popularity, particularly as they do not bring a risk of a local inflammatory reaction as corneal inlays do. Disadvantages of using the pinhole effect include high susceptibility to decentration, decrease in retinal luminance levels, and difficulties in performing fundus examinations or surgery in eyes with implanted devices. There are also concerns regarding perceptive issues with different retinal illuminances in the 2 eyes (the Pulfrich effect).

Defocus Curve of Emerging Presbyopic Patients

Purpose

To create a defocus curve of emerging presbyopic patients of various age groups.

Setting

Single site private practice in Sioux Falls, South Dakota.

Design

This was a non-randomized, prospective study. All subjects were enrolled from healthy volunteers.

Methods

Subjects aged 37-9, 40-42, 43-45 and 46-48 that have 20/20 best-corrected distance visual acuity (BCDVA) were included. Binocular visual acuity at different defocus steps ranging from +0.5 D to -3 D was measured in each age group. Defocus curves were generated from the mean logMAR visual acuities at each defocus step, by age group.

Results

Of the 60 subjects, 23.3% of subjects were between the ages of 37-39, 26.7% were between the ages of 40-42, 25% of subjects were between ages 43-45, and 25% were between the ages of 46-48. Visual acuity significantly decreased from plano to -3 D defocus steps in all groups (p < 0.0002, p = 0, p = 0 and p = 0). The 46-48-year-old group had worse visual acuity compared to the other three groups from the -1.0 to -2.0 D defocus steps (p = 0.037, p = 0.022 and 0.017, respectively). Starting at a near point of 40cm, the 37-39 group had the best logMAR vision and the 46-48 group had the worst vision (p = 0.001).

Conclusion

The defocus curves of emerging presbyopic individuals demonstrate a decreasing visual acuity at near defocus steps that decreases with age. Defocus curves at different age ranges can help doctors explain various presbyopia treatment options in terms of near point capabilities at various ages.

New insights in presbyopia: impact of correction strategies

Presbyopia occurs when the physiologically normal age-related reduction in the eyes 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. Hence, it is more about the impact it has on an individual’s visual ability to function in their environment to maintain their lifestyle than a measured loss of focusing ability. Presbyopia has a significant impact on an individual’s quality of life and emotional state. While a range of amelioration strategies exist, they are often difficult to access in the developing world and prescribing is generally not optimal even in developed countries. This review identified the need for a standardised definition of presbyopia to be adopted. An appropriate battery of tests should be applied in evaluating presbyopic management options and the results of clinical trials should be published (even if unsuccessful) to accelerate the provision of better outcomes for presbyopes.

Small-aperture intracorneal inlay implantation in emmetropic presbyopic patients: a systematic review

Small-aperture corneal inlays, commonly known as KAMRA, are tiny optical devices inserted in the corneal stroma aiming to gain near vision in patients with presbyopia. The purpose of this study was to systematically review case series of small-aperture corneal inlays performed in presbyopic emmetropic patients and to evaluate the visual outcomes of this procedure. This systematic review included 18 articles published between 2011 and 2018, overall studying 2724 eyes from 2691 participants. The mean longest follow-up was 19 months. Results showed that 78.5% of eyes reported an uncorrected near visual acuity of 20/32 or better and 90.50% of eyes achieved an uncorrected distance visual acuity of 20/25 or better. All patients experienced an improvement in uncorrected near visual acuity with a patient satisfaction ranging between 60% and 90%. The highlighted complications were keratocyte activation leading to corneal stromal haze, epithelial growth, iron deposits and poor distance visual acuity. Explantation was carried out in 101 eyes (3.7%) due to distance vision blurriness, development of epithelial microcysts, incorrect implant placement or hyperopic shift changes. KAMRA demonstrated high efficacy. However, safety and satisfaction rates remain unclear. Despite the low explantation rates reported in the literature, some complications were permanent. The results and conclusions should be taken with caution due to the conflict of interest stated in the reviewed articles.

Small Aperture IC-8 Extended-Depth-of-Focus Intraocular Lens in Cataract Surgery: A Systematic Review

The aim of this paper is to evaluate the visual outcomes and patient satisfaction of small aperture IC-8 IOLs in cataract patients with or without prior ocular events. A systematic review of full-length original English studies reporting the visual results of small aperture IC-8 IOL implantation after cataract surgery in three databases, PubMed, Web of Science and Scopus, was performed according to the PRISMA statement. The Quality Assessment Tool for case series studies from the National Heart, Lung, and Blood Institute was used to analyze the quality of the studies selected. The search provided 543 articles, of which 22 were included in this systematic review. Significant improvements in uncorrected distance visual acuity (UDVA); uncorrected intermediate visual acuity (UIVA); uncorrected near visual acuity (UNVA); perception of photic phenomena; and patient satisfaction have been reported. Unilateral and bilateral small aperture IC-8 IOL implantation reduces photic phenomena and provides good vision for all distances with high patient satisfaction and minimal postoperative complications. Therefore, the implantation of this IOL may be recommended for patients with cataracts, corneal irregularities and ocular trauma with partial aniridia.

Refractive corneal inlay implantation outcomes: a preliminary systematic review

PURPOSE

To review all case series of refractive corneal inlay implantation: Flexivue (Presbia, Netherlands), Invue (BioVision, Brügg, Switzerland) and Icolens (Neoptics, Hünenberg, Switzerland) performed in presbyopia patients and to evaluate the reported visual outcomes. In addition, our aim is to provide assessment for complications and to report the satisfaction rates.

METHODS

PubMed, Web of Science and Scopus databases were consulted using "refractive corneal inlay", "Flexivue Inlay", "Invue Inlay" and "Icolens inlay" as keywords. 147 articles were found, and they were assessed considering the inclusion and exclusion criteria. After filtering, this systemic review included ten articles, published between 2011 and 2020.

RESULTS

308 eyes from 308 participants were enrolled in this systematic review. Mean maximum follow-up was 13.9 months. Nine of the ten case series included used femtosecond laser for the corneal pocket creation. Mean pocket depth was 293.75 µm. 77.5% of the eyes reported a postoperative uncorrected near visual acuity of 20/32 or better, and 19.20% of the inlay-implanted eyes achieved an uncorrected distance visual acuity of 20/20 or better. The most prominent complications were halos, pain, photophobia, and poor distance visual acuity. 27 eyes (8.7%) had to be explanted due to complications, such as near-distance spectacle dependence or blurred distance vision.

CONCLUSION

Refractive corneal inlay outcomes demonstrated high efficacy, safety, and satisfaction rates. Furthermore, it is a reversible technique. However, the findings must be viewed with caution due potential conflict of interest. Further research with higher sample size is needed to validate these findings.

Non-diffractive wavefront shaping extended depth of focus (EDoF) intraocular lens: visual performance and patient-reported outcome

PURPOSE

To evaluate visual performance and patient-reported outcomes after bilateral implantation of new non-diffractive wavefront shaping extended depth of focus (EDOF) intraocular lens (IOL).

SETTING

Department of Ophthalmology, Goethe University, Frankfurt, Germany.

DESIGN

Prospective, single-arm, single-center study.

METHODS

Patient population: We included 16 patients (32 eyes) who received bilateral implantation of a non-diffractive wavefront shaping EDOF IOL (AcrySof® IQ Vivity®, Alcon Research, TX, USA). Target refraction in both eyes was emmetropia. Observation procedure: Monocular and binocular uncorrected (UCVA) and distance-corrected (DCVA) visual acuity (VA), refractive outcome, defocus curve, contrast sensitivity (CS) were evaluated 3 months after surgery with a questionnaire on optical phenomena and spectacle independence. Main Outcome measure: Three months postoperative monocular and binocular UCVA and DCVA (logMAR); defocus curve; CS; and quality of vision (QoV) questionnaire results.

RESULTS

Mean spherical equivalent was -0.16 ± 0.37 D 3 month postoperatively. Binocular UDVA at distance, intermediate, and near was 0.01 ± 0.05 logMAR at 4m, 0.05 ± 0.05 logMAR at 80cm, 0.07 ± 0.06 logMAR at 66cm, and 0.25 ± 0.11 logMAR at 40cm, respectively. Despite some minor optical phenomena, 88% of patients would choose the same lens. 63% of patients reported no optical phenomena at all. Contrast sensitivity was 1.25 ± 0.41 logCS (photopic), 0.96 ± 0.24 logCS (mesopic) and 0.93 ± 0.24 (mesopic + glare).

CONCLUSIONS

This non-diffractive wavefront shaping EDOF IOL provides good VA at far and intermediate distance and functional near VA. It showed good QoV and CS, and high spectacle independence for distance and intermediate vision with significantly less optical phenomena than with other EDOF or MIOLs.

Future Intraocular Lens Technologies

The future of intraocular lens (IOL) technology has already begun with a number of recent innovations. The postoperative change of refractive power will lead to a customized fine-tuning that provides patients with the individual vision they expect and with as much spectacle independence as possible. The latest-generation (2.0) Light-Adjustable Lens (RxSight) was recently introduced into clinical practice, with the first results being very encouraging. Other methods of altering the power of an already implanted IOL are under development. The same can be said about the correction of presbyopia, the so-called last frontier in refractive surgery. Extended depth-of-focus IOLs have been introduced, as has the technology of the pinhole IOL. The latter has therapeutic potential beyond the refractive aspect and has already proven helpful in cases of iris defects and irregular corneas. Several technologies are currently being tested to achieve-finally-an accommodative IOL. One such concept uses the (remaining) strength of the ciliary muscle, whereas another is triggered by the pupil reaction when shifting focus from far to near. Not an IOL itself, but rather a high-tech innovation that so far has mostly been implanted during cataract surgery, is a microelectronic sensor that measures habitual intraocular pressure (IOP) at any given time and promises to revolutionize the management of glaucoma patients. The last generation of this device (Eyemate; Implandata Opthalmics Products GmbH) is implanted during small-incision cataract surgery; the latest development is an even smaller sensor that will be inserted suprachoroidally before, in the near future, such a device will be part of a capsular ring. These IOP sensors are a prime example that IOL technology will continue to be a driving force in ophthalmology, with a positive impact far beyond cataract surgery.

Toric intraocular lens combined with a supplementary pinhole implant to treat irregular corneal astigmatism

A case of refractive lens exchange with the implantation of a supplementary intraocular pinhole (IOPH) to treat a challenging case of keratoconus is presented. Four months after the initial procedure, an intraocular lens (IOL) exchange (under the IOPH) was performed to a toric implant to correct the residual manifest astigmatism. This significantly improved both distance and near acuities and demonstrates how a toric IOL and astigmatism correction in combination with a pinhole device could be used to treat selected cases of keratoconus.

Clinical outcomes of a novel presbyopia-correcting soft contact lens with a small aperture

PURPOSE

To investigate the efficacy and safety of a newly developed pinhole soft contact lens (Eyelike Pinhole II; Koryo Eyetech Co. Ltd.) for presbyopia correction.

METHODS

This prospective clinical study enrolled 29 patients with presbyopia between October 2018 and December 2018. All participants wore the Eyelike Pinhole II in the non-dominant eye for >3 h/day for a period of 1 week. Binocular and monocular uncorrected near visual acuities, distance-corrected near visual acuity (DCNVA), uncorrected distance visual acuity, and corrected distance visual acuity (CDVA) were measured before and after the intervention. All visual acuities were measured in logarithm of the minimal angle of resolution (logMAR) units. In addition, binocular defocus curves were generated, and contrast sensitivity values were obtained under photopic and mesopic conditions before and after lens wear.

RESULTS

The mean DCNVA of the treated eye and the mean binocular DCNVA improved from 0.34 ± 0.12 to 0.15 ± 0.14 (P < 0.001) and 0.31 ± 0.13 to 0.11 ± 0.10 (P < 0.001) logMAR, respectively, after pinhole contact lens wear. Although the mean CDVA of the treated eye deteriorated from -0.04 ± 0.05 to 0.02 ± 0.11 logMAR (P = 0.015), there was no significant change in the mean binocular CDVA (P = 0.79). The binocular defocus curve showed a significant improvement from -5.0 dioptres (D) to -1.0 D after pinhole contact lens wear.

CONCLUSIONS

The newly developed Eyelike Pinhole II soft contact lens showed safe and effective outcomes; thus, it could be a promising option for the treatment of presbyopia.

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

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.