The Effect of Light Level and Small Pupils on Presbyopic Reading Performance

BCLA CLEAR Presbyopia: Epidemiology and impact

The global all-ages prevalence of epidemiologically-measured 'functional' presbyopia was estimated at 24.9% in 2015, affecting 1.8 billion people. This prevalence was projected to stabilise at 24.1% in 2030 due to increasing myopia, but to affect more people (2.1 billion) due to population dynamics. Factors affecting the prevalence of presbyopia include age, geographic location, urban versus rural location, sex, and, to a lesser extent, socioeconomic status, literacy and education, health literacy and inequality. Risk factors for early onset of presbyopia included environmental factors, nutrition, near demands, refractive error, accommodative dysfunction, medications, certain health conditions and sleep. Presbyopia was found to impact on quality-of-life, in particular quality of vision, labour force participation, work productivity and financial burden, mental health, social wellbeing and physical health. Current understanding makes it clear that presbyopia is a very common age-related condition that has significant impacts on both patient-reported outcome measures and economics. However, there are complexities in defining presbyopia for epidemiological and impact studies. Standardisation of definitions will assist future synthesis, pattern analysis and sense-making between studies.

Impact of Light Conditions on Visual Performance following Premium Pseudophakic Presbyopia Corrections

The primary objective of this study was to objectively compare the visual performance of patients following premium pseudophakic presbyopia corrections in different light combinations for near- and intermediate-vision activities of daily living (ADLs). This is a prospective, comparative study. A total of 75 patients populated three study groups: G1-patients with bilateral trifocal implantation, G2-patients with bilateral bifocal implantation, and G3-patients with bilateral monofocal implantation. All participants addressed 10 ADLs in nine combinations of light temperature (3000 K, 4000 K, and 6000 K) and light intensity (25 fc, 50 fc, and 75 fc) and declared their subjectively optimal light combination while reading. G2 and G3 had the best total ADL scores in 6000 K/75 fc, while G1 had the best total ADL score in 4000 K/75 fc. Total ADL, easy ADL, and moderate difficulty ADL scores were significantly better in G2, while difficult ADL score was significantly better in G1. The majority of all groups selected 6000 K/75 fc as the most comfortable light combination, and no group selected 3000 K and 25 fc. In conclusion, trifocal patients benefit from intense daylight, while bifocal and monofocal patients benefit from intense, cold lighting. Trifocal patients present superior near-vision capacity in difficult near-vision daily tasks, while bifocal patients present superiority in easy and moderate-difficulty ADLs.

Non-Miotic Improvement in Binocular Near Vision with a Topical Compound Formula for Presbyopia Correction

INTRODUCTION

The aim of this case series was to examine the association between unaided binocular visual acuity for near vision and pupil change after the instillation of a special topical formulation for presbyopia treatment.

METHODS

This was a case series consisting of consecutive participants with presbyopia aged 40-70 years who were tested for visual acuity and pupil diameter before and 2 h after instillation of a formulation of pilocarpine and phenylephrine drops (FOV Tears) for presbyopia. Participants underwent subjective refraction, photopic and scotopic pupil diameter measurement and unaided monocular and binocular visual acuity testing by logMAR for distance and near vision both pre- and post-instillation of eye drops.

RESULTS

The study enrolled 363 subjects (n = 176 women, 48%) with a mean (± standard deviation) age of 50.4 ± 5.8 years. Mean spherical equivalent (SE) changed significantly (- 0.17 Diopters) after instillation of the FOV Tears formulation (p < 0.001). Post-instillation of eye drops, the scotopic pupil diameter decreased by 0.97 ± 0.98 mm, and the near visual acuity by logMAR improved significantly by nearly two lines (p < 0.01). In the linear regression analyses, age (p < 0.001) and SE pre-drop instillation (p < 0.001) were associated with unaided binocular visual acuity. The changes in photopic pupil diameter and the scotopic pupil diameter were not associated with unaided binocular visual acuity.

CONCLUSIONS

The use of the pilocarpine and phenylephrine formulation (FOV Tears) improved binocular visual acuity for near vision in presbyopic patients, and the effect was independent of pupil change.

Complications of Small Aperture Intracorneal Inlays: A Literature Review

Presbyopia can be defined as the refractive state of the eye in which, due to a physiological decrease in the ability to accommodate, it is not possible to sustain vision without fatigue in a prolonged manner, along with difficulty focusing near vision. It is estimated that its prevalence in 2030 will be approximately 2.1 billion people. Corneal inlays are an alternative in the correction of presbyopia. They are implanted beneath a laser-assisted in situ keratomileusis (LASIK) flap or in a pocket in the center of the cornea of the non-dominant eye. The purpose of this review is to provide information about intraoperative and postoperative KAMRA inlay complications in the available scientific literature. A search was conducted on PubMed, Web of Science, and Scopus with the following search strategy: ("KAMRA inlay" OR "KAMRA" OR "corneal inlay pinhole" OR "pinhole effect intracorneal" OR "SAICI" OR "small aperture intracorneal inlay") AND ("complication" OR "explantation" OR "explanted" OR "retired"). The bibliography consulted shows that the insertion of a KAMRA inlay is an effective procedure that improves near vision with a slight decrease in distance vision. However, postoperative complications such as corneal fibrosis, epithelial iron deposits, and stromal haze are described.

Age-specific influences of refractive error and illuminance on pupil diameter

To assess the most influential factor for pupil diameter changes among age, illuminance, and refractive state and reestablish the optimal procedures for clinical applications based on refractive state and illuminance for different age groups. The study was an observational study (repeated measure study). Participants included 219 Korean adults aged 20 to 69 years. Pupil diameters were measured using a pupilometer under scotopic, mesopic-low, and mesopic-high lighting conditions. Factor interactions among age, illuminance, and refractive state were evaluated using mixed linear model and chi-square automated interaction detection. Illuminance mainly contributed to variations in pupil diameter of participants over 50 years, whereas the refractive state was the dominant controlling factor for the pupil variation in participants below 50 years. For more generalized application, the pupil diameter decreased with older age and brighter illuminance (P < .001, inverse correlation, all comparisons). The mean pupil diameter was significantly higher in myopes and emmetropes than in hyperopes (P < .001). Pupil diameter variation modeled using the mixed model confirmed age, illuminance, and refractive error as significant factors (P < .001). Accounting for the interactions among age, illuminance, and refractive error and establishing their hierarchical dominance can be generalized using the chi-square automated interaction detection method and mixed model. Promoting age-dependent consideration for both illuminance and refractive state is necessary when pupil diameters play significant roles in clinical and manufacturing circumstances.

Development and Validation of a Lighting Facility for the Objective Assessment of the Visual Performance of Presbyopic Patients in a Series of Activities of Daily Living

Introduction The primary objective of this study is to develop and validate an experimental lighting facility that allows the evaluation of near and intermediate vision in different user-defined illuminance levels. Methods This is a prospective, randomized, controlled study. Normophakic patients populated three validation groups (VGs) according to their binocular uncorrected near visual acuity (UNVA): a) VG1, 0.0-0.1 logMAR; b) VG2, 0.4 logMAR; and c) VG3, 0.7 logMAR. All participants addressed 10 near and intermediate activities of daily life (ADLs) in the three following lighting settings: 1) 25 foot candles (fc)/3000 kelvins (K), 2) 50 fc/4000 K, and 3) 75 fc/6000 K. Results Thirty patients in each group performed all ADLs in the three lighting settings. VG1 demonstrated the best ADL scores in all ADLs and lighting settings, followed by the VG2. VG3 presented the worst scores. ADLs using printed material showed significant differences among the three lighting settings for all study groups, while ADLs using screens or needing manual dexterity demonstrated no significant differences except for the Screwdriver Test (ST) in VG1. All ADL scores demonstrated a high correlation with UNVA in all lighting settings (p < 0.001). Conclusion This is the first study that validates a lighting facility for comparative studies in patients with different near vision capacities performing a series of ADLs.

Multifocal contact lenses: A bibliometric study

PURPOSE

To analyze the state of scientific publications in multifocal contact lenses field through a bibliometric study.

METHODS

The database used to carry out the study was SCOPUS and contained the descriptors "multifocal contact lens", "bifocal contact lenses", "progressive contact lenses" and "presbyopia contact lenses", limited to the fields of title, keywords and abstract. The indicators applied in this research were: doubling time and annual growth rate, Price's transience index, Lotka's law of scientific productivity, and Bradford's zones.

RESULTS

A total of 346 articles were published between 1960 and 2019. The growth in the number of publications matches the exponential adjustment slightly better (R = 0.53). The duplication time was 13.2 years. The productivity level is focused on articles with an average number of authors of just 2.06 per article. The Bradford core was formed by two journals, Optometry and Vision Science and Eye and Contact Lens.

CONCLUSIONS

Research on multifocal contact lenses has exponential growth, without evidence of having reached a saturation point. The main countries in scientific production in this field are the United States and Australia.

Phentolamine Mesylate Ophthalmic Solution Provides Lasting Pupil Modulation and Improves Near Visual Acuity in Presbyopic Glaucoma Patients in a Randomized Phase 2b Clinical Trial

PURPOSE

Phentolamine mesylate ophthalmic solution (PMOS), applied to the eye topically, was shown previously to have beneficial effects in patients with dim light vision disturbances (DLD), including decreased pupil diameter (PD), improved best-corrected distance visual acuity (BCDVA), as well as lower intraocular pressure (IOP). The ORION-1 trial evaluated the long-term safety and efficacy of PMOS in a glaucomatous, presbyopic population.

PATIENTS AND METHODS

In this randomized, double-masked, multi-center, placebo-controlled, multiple-dose Phase 2b trial, 39 patients with elevated IOP were randomized to receive one evening dose of study medication or placebo for 14 days. The primary outcome measure was mean change in diurnal IOP, and the key secondary outcome measures included changes in PD, distance-corrected near visual acuity (DCNVA), and conjunctival hyperemia.

RESULTS

Use of 1% PMOS did not lead to a statistically significant decrease in diurnal IOP compared to placebo (P = 0.89) but trended toward a greater decrease in patients with lower IOP baselines. PMOS produced a statistically significant mean 20% PD reduction under both photopic and mesopic conditions that was sustained for 36 hours post-dosing. A statistically significant number of patients with PMOS compared to placebo demonstrated ≥1 line of improvement in photopic DCNVA at day 8 (P = 0.0018), day 15 (P = 0.0072), and day 16 (P = 0.0163), with a trend for 2- and 3-line improvements at all time points. There was no statistical difference in conjunctival hyperemia compared to placebo.

CONCLUSION

Although mean IOP was not lowered significantly, daily evening dosing of 1% PMOS was found to be well tolerated with no daytime conjunctival redness and demonstrated improvement in DCNVA with sustained PD reduction in a glaucomatous and presbyopic population. Smaller pupil size can have beneficial effects in improving symptoms of presbyopia and DLD, which will be the focus of further studies.

Time-course of the visual Impact on presbyopes of a low dose miotic

PURPOSE

To examine the pupil and visual impact of a single early morning drop of a low concentration miotic.

METHODS

Pupil size, refraction, visual acuity (VA), near reading performance and intraocular pressure were monitored for 8 h at a wide range of light levels following bilateral instillation of single drops of 0.1% brimonidine tartate in 19 early presbyopes (40-50 years) and 11 mature presbyopes (>50 years).

RESULTS

Pupil miosis did not alter distance VA or refraction. Significant pupil miosis peaked at 1-2 h after dosing, which expanded the depth of focus of mature presbyopes with the mean improvement in near logMAR VA of -0.15, -0.07 and -0.03, at 20, 200 and 2000 lux, respectively. One hour after instillation, near reading speed improved by 21, 24 and 5 words per min for text size commonly seen in US newspaper and cellphone text messages, 18, 21 and 19 words per min for text size of grocery labels and 12, 13 and 30 words per min for text size of over-the-counter medications at light levels of 20, 200 and 2000 lux, respectively. No such improvements in near VA and near reading speed were observed in the young presbyopes having some residual accommodation. Most of the pupil miosis remained 8 h after instillation, whereas near VA improvements disappeared after 4 h.

CONCLUSION

Low dose miotics can enhance near vision in presbyopic subjects while retaining high quality distance vision over a wide range of light levels. Significant improvements in near vision were observed only during the 1-2 h period after dosing when miosis peaked.

The Effect of Retinal Illuminance on the Subjective Amplitude of Accommodation

SIGNIFICANCE

We show that the amplitude of accommodation decreases with retinal illumination even under photopic reading conditions and a constant pupil size. This result provides a basis for clinical approaches that are not based on an optical explanation.

PURPOSE

We investigated the effect of retinal illuminance on the amplitude of accommodation while the pupil of the eye remained constant.

METHODS

The amplitudes of accommodation of 10 young subjects (from 20 to 38 years of age) and that of 10 presbyopic subjects (from 45 to 54 years of age) were measured subjectively through an artificial pupil of 5 mm using a Badal optometer and for four values of retinal illuminance: 222, 821, 2138, and 5074 trolands. Phenylephrine was instilled to all the subjects to ensure that their natural pupil was greater than the artificial one in all experimental runs. Linear mixed-effects model for repeated measures with age and log luminance as covariates were used to check whether changes in amplitude of accommodation with retinal illumination were statistically significant.

RESULTS

In the range of illuminances tested, the amplitude of accommodation decreased on average from 6.34 to 4.35 D in the young subjects and from 1.69 to 1.04 D in the presbyopic subjects. Illuminance was associated with the amplitude of accommodation in both young and presbyopic groups, with P < .01.

CONCLUSIONS

The reduction in the amplitude of accommodation with target illumination (a phenomenon named night presbyopia) under photopic light conditions is not only due to a reduction in the depth of focus as a consequence of pupil dilation; it is strongly affected by the decrease of retinal illumination.

Testing impacts of global blur profiles using a multiscale vision simulator

Although it is possible to specify the impact of blur at a specific retinal location, a lack of understanding exists regarding how the inhomogeneous blur distribution across the retina (i.e., global blur) affects the quality of an optical correction at a specific retinal location. To elucidate this issue, a multiscale visual simulator combining the projection of a controllable high-resolution stimulus and an ocular monitoring system was constructed to simultaneously simulate foveal and extrafoveal blurs. To define the range and capability of a wide-angle stimulation, an optimal working pupil was evaluated by optical ray-tracing via a Monte Carlo simulation, including optical variations corresponding to fixational eye movements. To investigate the impacts of global blur on the perception of discrete regions of the visual field, the bothersome blur threshold from five subjects was measured through this novel system using a collection of zonal blurs (annuli image projected sequentially at discrete retinal regions), and these impacts were compared with those using a spatially-varying blur (continuum of simultaneously projected zonal blurs of varying strengths, simulating retinal blur variations). Our results show that the zonal blur threshold does not entirely predict the global blur threshold, having a tendency to overestimate blur the threshold. It was concluded that, in addition to the amount of defocus present at a defined retinal location, the perception of individual defocused retinal regions can be affected by global blur. Given that blur tolerance can affect the perception of optically induced blurs, the findings provide useful implications for designing new optical correction.

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.

Impact of light conditions on reading ability following multifocal pseudophakic corrections

Purpose

To examine the impact of light intensity and temperature on reading performance following bilateral pseudophakic multifocal presbyopic correction.

Patients and methods

This is a prospective clinic-based trial conducted at the Department of Ophthalmology in the University Hospital of Alexandroupolis, Greece. Three groups of patients were formed (G1: patients with bilateral bifocal implantation, G2: patients with bilateral trifocal implantation, and control group: patients with bilateral pseudophakic monofocal implantation). Reading ability was quantified with the Greek version of MNREAD chart with minimal reading speed at 80 words/min for the following light intensities (25, 50, and 75 Foot-Candles [FC]) and temperatures (3,000, 4,000, and 6,000 K). Preferred light conditions for reading were assessed, as well. ClinicalTrials.gov Identifier: NCT03226561.

Results

Control group demonstrated significantly lower reading ability at all light combinations with maximal ability at 75 FC and 6,000 K (0.58±0.18 logMAR). Bifocal group presented a light-dependent reading ability that ranged from 0.45±0.08 logMAR (25 FC and 3,000 K) to 0.40±0.11 logMAR (75 FC and 4,000 or 6,000 K). Trifocal participants presented the best reading ability that was light intensity-independent; however, their performance was reduced at 6,000 K. G1 and G2 preferred primarily intermediate light temperature, while control participants preferred cold light temperature.

Conclusion

Multifocal pseudophakic corrections improve reading ability; however, they present variable efficacy according to the light conditions.

Interaction of aberrations, diffraction, and quantal fluctuations determine the impact of pupil size on visual quality

Our purpose is to develop a computational approach that jointly assesses the impact of stimulus luminance and pupil size on visual quality. We compared traditional optical measures of image quality and those that incorporate the impact of retinal illuminance dependent neural contrast sensitivity. Visually weighted image quality was calculated for a presbyopic model eye with representative levels of chromatic and monochromatic aberrations as pupil diameter was varied from 7 to 1 mm, stimulus luminance varied from 2000 to 0.1  cd/m², and defocus varied from 0 to -2 diopters. The model included the effects of quantal fluctuations on neural contrast sensitivity. We tested the model's predictions for five cycles per degree gratings by measuring contrast sensitivity at 5  cyc/deg. Unlike the traditional Strehl ratio and the visually weighted area under the modulation transfer function, the visual Strehl ratio derived from the optical transfer function was able to capture the combined impact of optics and quantal noise on visual quality. In a well-focused eye, provided retinal illuminance is held constant as pupil size varies, visual image quality scales approximately as the square root of illuminance because of quantum fluctuations, but optimum pupil size is essentially independent of retinal illuminance and quantum fluctuations. Conversely, when stimulus luminance is held constant (and therefore illuminance varies with pupil size), optimum pupil size increases as luminance decreases, thereby compensating partially for increased quantum fluctuations. However, in the presence of -1 and -2 diopters of defocus and at high photopic levels where Weber's law operates, optical aberrations and diffraction dominate image quality and pupil optimization. Similar behavior was observed in human observers viewing sinusoidal gratings. Optimum pupil size increases as stimulus luminance drops for the well-focused eye, and the benefits of small pupils for improving defocused image quality remain throughout the photopic and mesopic ranges. However, restricting pupils to <2  mm will cause significant reductions in the best focus vision at low photopic and mesopic luminances.