Perception and awareness of the public about presbyopia and its corrective approaches in Saudi Arabia: a population-based survey.

BACKGROUND: This study investigated patients' awareness of presbyopia and its management approaches and their preferred methods for near vision correction. METHODS: In Saudi Arabia, 785 participants (aged between 35 and 60 years) completed a structured survey online, consisting of hard copies and direct interviews. The survey consisted of twenty-eight items divided into three parts. It was designed to record participants' awareness of and preferences for presbyopia and its refractive corrections. Nonparametric tests and descriptive analyses were conducted to analyse participants' responses. RESULT: Approximately half of the participants had difficulty with near vision activities, such as reading newspapers or using mobile phones. Among all the participants, 76% were not aware of presbyopia. The prevalence of uncorrected presbyopia was 48% of the 785. The majority (82%) felt that spectacles were acceptable for correction of presbyopia. Most reported that they did not experience social stigma when using reading spectacles (87% of participants). When asked if they were aware of management approaches other than spectacles, 72% responded with not at all. Most participants had no earlier knowledge of the use of multifocal contact lenses or eye drops for presbyopia correction (67% and 82%, respectively). In the present study, some tendencies to use corrective approaches to presbyopia other than spectacles were noted. Finally, participants' age, sex, region, education, and income had a statistically significant impact on essential parts of their responses (p < 0.05). CONCLUSION: Presbyopia is a highly prevalent age-related ocular disorder, and a significant percentage of cases are uncorrected due to a lack of awareness or reluctance to wear spectacles. More efficient health education about presbyopia and its corrective alternatives is urgently needed.

Visual performance of new affordable and auto-adherent lenses for presbyopia correction.

Presbyopia is a visual condition that affects all of us, evolving with time, reducing the range of accommodation and the ability to work at near. Reading glasses, bifocals or multifocal lenses are the most common solutions. In this work, we demonstrate the near visual performance of new elastomeric auto-adherent lenses developed for the correction of presbyopia. Visual acuity and contrast sensitivity were measured in 10 presbyopic subjects. The results showed that wearing either conventional trial ophthalmic lenses or the new elastomeric lenses provided similar visual quality. These elastomeric lenses can be placed in, or removed from the distance-vision spectacles of the wearers, providing an affordable solution for correcting presbyopia at its clinical onset, which might be especially useful in subjects with different refractive error in each eye and for those with astigmatism.

Gaze and behavioural metrics in the refractive correction of presbyopia.

PURPOSE: To investigate gaze and behavioural metrics at different viewing distances with multifocal contact lenses (MFCLs), single vision contact lenses (SVCLs) and progressive addition lenses (PALs). METHODS: Fifteen presbyopic contact lens wearers participated over five separate study visits. At each visit, participants were randomly assigned to wear one of five refractive corrections: habitual PAL spectacles, delefilcon A (Alcon Inc.) MFCLs and three separate pairs of delefilcon A single vision lenses worn as distance, intermediate and near corrections. Participants wore a Pupil Core headset to record eye and head movements while performing three visual tasks: reading, visual search and scene observation. Data were investigated using linear regression and post-hoc testing. Parameters of interest included gaze (fixation duration, head movement) and behavioural (reading speed, reading accuracy, visual search time) metrics. RESULTS: Reading speed in SVCLs was significantly faster than in MFCLs and PAL spectacles (F = 16.3, p < 0.0001). Refractive correction worn did not influence visual search times (F = 0.16, p = 0.85). Fixation duration was significantly affected by the type of visual task (F = 60.2, p < 0.001), and an interaction effect was observed between viewing distance and refractive correction (F = 4.3, p = 0.002). There was significantly more horizontal and vertical head movement (F = 3.2, p = 0.01 and F = 3.3, p = 0.01, respectively) during visual search tasks when wearing PAL spectacles compared to SVCLs or MFCLs. CONCLUSION: This work showed that the type of refractive correction affects behavioural metrics such as reading speed and gaze behaviour by affecting horizontal and vertical head movements. The findings of this study suggest that under certain conditions, wearers of MFCLs make fewer head movements compared to PAL spectacles. Gaze behaviour metrics offer a new approach to compare and understand contact lens and spectacle performance, with potential applications including peripheral optical designs for myopia management.

A Study to Understand Challenges and Factors that Influence Effective Yoga Interventions for Presbyopia using CLARIFY Guidelines.

The demand for treating diseases using yoga therapy, a Complementary and Alternative Medicine (CAM) treatment, has increased globally. An increase in the research in this yoga area from fewer than 10 research publications per year in the 1990s to at least 20 per year after 2010 is evidence of this change in treatment needs over time. The beneficial effect of yoga therapy has been limited to practice in acute care despite its remarkable success in this domain. This is due to many factors that impact the therapy's effectiveness, irrespective of disease indications. However, the prime challenges for its effectiveness lie with the reliability of the yoga trial outcome and reporting. There is a great need to reevaluate the yoga trials' reporting for the reliability of their outcome. This study attempts to address the issue by studying challenges for presbyopia with yoga interventions. Among many indications, progressive vision loss (presbyopia), which occurs due to refractive errors in the ocular region, has scope to be treated effectively with yoga therapies. However, trials for yoga interventions for treating refractive errors have not been studied well. This study was conducted to understand the challenges in yoga therapy trials and its potential to treat presbyopia. The CLARIFY guidelines were used to understand the challenges and factors that impact effective treatment in the current research landscape. We found that trials conducted are not in compliance with the reporting guidelines. Adaptation of CLARIFY guidelines is essential to produce reliable evidence to prescribe yoga therapies to treat refractive errors.

Refractive Lens Exchange: A Review.

In recent decades, technical advancements in lens surgery have considerably improved safety and refractive outcomes. This has led to a much broader range of indications for refractive lens exchange (RLE). Effective restoration of uncorrected distance and near visual acuity is possible with modern presbyopia correcting intraocular lenses (IOLs). Hyperopic patients who are fully presbyopic were identified as ideal candidates for RLE. For myopic patients, an increased risk of retinal detachment has been reported, which leads to a higher threshold to perform RLE in this patient group. The most frequent postoperative complications include posterior capsular opacification, deviation from the target refraction and cystoid macular edema. Thus, adequate planning of surgery, careful patient selection, as well as comprehensive counseling are crucial for successful RLE.

Vergence-Accommodation Conflict: Increased Presbyopia in Virtual Reality.

BACKGROUND: Performance and symptoms in completing a visual search task on a PC monitor and using a head-mounted display (HMD) were compared for different viewing conditions and between users of different ages. PATIENTS AND METHODS: Twenty-three young (M = 30 y, SD = 7 y) and 23 older (M = 52 y, SD = 5 y) participants performed a visual search task presented on a PC monitor. The task was repeated using an HMD for a near and a far virtual viewing distance. Reaction times (RT), detection sensitivity (d'), and symptoms were recorded for the three different viewing conditions. RESULTS: RT and d' were not affected by the viewing condition (p > 0.05). In contrast, symptoms significantly depended on the viewing condition but were, in part, not significantly affected by age. It is interesting to note that although not significant, young participants reported more ocular symptoms than older participants in the near vision task carried out using the HMD. DISCUSSION: HMD increases visual symptoms. However, HMD could be, in part, a remedy to problems when using visual aids for near work, in particular for presbyopes.

Promotion of Protein Solubility and Reduction in Stiffness in Human Lenses by Aggrelyte-1: Implications for Reversing Presbyopia.

With aging, human lenses lose the ability to focus on nearby objects due to decreases in accommodative ability, a condition known as presbyopia. An increase in stiffness or decrease in lens elasticity due to protein aggregation and insolubilization are the primary reasons for presbyopia. In this study, we tested aggrelyte-1 (S,N-diacetyl glutathione diethyl ester) for its ability to promote protein solubility and decrease the stiffness of lenses through its dual property of lysine acetylation and disulfide reduction. Treatment of water-insoluble proteins from aged human lenses (58-75 years) with aggrelyte-1 significantly increased the solubility of those proteins. A control compound that did not contain the S-acetyl group (aggrelyte-1C) was substantially less efficient in solubilizing water-insoluble proteins. Aggrelyte-1-treated solubilized protein had significant amounts of acetyllysine, as measured by Western blotting and LC-MS/MS. Aggrelytes increased the protein-free thiol content in the solubilized protein. Aged mouse (7 months) and human (44-66 years) lenses treated with aggrelyte-1 showed reduced stiffness accompanied by higher free thiol and acetyllysine levels compared with those treated with aggrelyte-1C or untreated controls. Our results suggested that aggrelyte-1 reduced lens stiffness through acetylation followed by disulfide reduction. This proof-of-concept study paves the way for developing aggrelyte-1 and related compounds to reverse presbyopia.

Testing the efficacy of vision training for presbyopia: alternating-distance training does not facilitate vision improvement compared to fixed-distance training.

PURPOSE: Current evidence demonstrates the effectiveness of vision training for presbyopia. We developed and examined a training program to test the effectiveness of alternating focal distances as a training method. METHODS: We devised a sharpness discrimination task, in which participants judged whether the stimulus was a sine- or square-wave grating, and tested in two training groups and one control group. In the alternating-distance training group (N = 8, age 49-64), participants had to alternate the fixation between a near- and far-screen. In the fixed-distance training group (N=8, age 47-65), participants fixated on the same-distance target for the whole block. Before and after the 20 training sessions, we measured the near- and far-visual acuity (VA) using the Landolt C and Early Treatment Diabetic Retinopathy Study (ETDRS) tasks and contrast sensitivity using the qCSF procedure. The control group (N=8, age 49-65) participated only in the pre- and post-tests. RESULTS: Both training groups showed a significant improvement between the pre- and post-tests in the Landolt C task, and the improvement sizes were not significantly different between the groups. In the ETDRS task, only the fixed-distance training group showed significant improvement, although there was no significant difference between the two groups. Neither group showed improvement in the contrast sensitivity task compared to the control group. CONCLUSION: The novel sharpness discrimination task can be an effective training method for presbyopia to prevent the deterioration of VA; however, contrary to popular belief, the effect of alternating-distance training was comparable to or even weaker than that of fixed-distance training.

Living with presbyopia: experiences from a virtual roundtable dialogue among impacted individuals and healthcare professionals.

BACKGROUND: Presbyopia is a common progressive vision disorder characterised by an inability to focus on near objects. The emergence of newer treatment options in addition to spectacles or contact lenses highlights the importance of assessing patient/user preferences. METHODS: People with presbyopia and healthcare professionals (HCPs) took part in a moderated, structured discussion of specific questions on a virtual advisory-board platform. The objective was to better understand unmet needs and the experience of living with the condition. Closed and open questions were included. RESULTS: Nine individuals (age 40 to 70 years) with presbyopia participated, from Australia, China, France, Italy, Ireland, Japan and the US. One ophthalmologist and one optometrist represented the perspective of HCPs. Over two weeks, 621 posts were entered on the platform. There was widespread agreement that the often stated association between age and presbyopia was unfortunate. Some participants had developed presbyopia at 30-45 years of age. What is more, the association with age was seen as implying a natural process, reducing the incentive to treat. Instead there was a call for an action-oriented view of presbyopia as a condition which may be effectively treated in the future. All participants experienced dealing with presbyopia as burdensome, affecting quality of life to varying degrees. When considering new treatments, convenience was the most important factor. The option to administer drops when needed was considered favourable, but short-acting treatments may not reduce inconvenience compared with spectacles. Participants viewed a therapy that targets the underlying cause of the condition favourably compared with symptomatic treatment. Side effects would severely reduce the appeal of drops. For clinical trials in presbyopia, patient-reported outcomes should be mandatory and need adequately to capture quality of life. Studies in presbyopia must be designed to minimise the inconvenience to participants in order to counter the risk of high drop-out rates. CONCLUSIONS: The interactive format provided insights into living with presbyopia, particularly the negative impact on quality of life, subjects' openness to new therapies, and the need to move away from considering the condition an unavoidable and intractable consequence of ageing.

The term presbyopia describes the difficulty to focus the eyes on things nearby, due to stiffening of the eye lens. The condition often considered something which worsens with increasing age. Many people cope with presbyopia by wearing reading glasses or bifocals, but alternative treatments are being developed. This publication reports from a moderated discussion among people with presbyopia and healthcare professionals specialising in eye health. People with presbyopia strongly felt that it should not be seen as an inevitable effect of middle age, but as something which may be treated medically. They felt that reading glasses, bifocals and monovision lenses were a daily burden and did not fit with how they wanted to live their lives. When discussing possible medical treatments, the option to use drops instead of glasses to improve eye sight appealed to the participants, particularly if the drops acted on the mechanism behind the stiffened lens with effect over many weeks or months. Convenience was the key benefit the participants would look for when considering a new treatment. Importantly, drops must not have any undesirable effects such as burning. The roundtable discussion showed the need for both healthcare professionals and those living with presbyopia to take the condition seriously with an an action-oriented view towards better therapies in the future.

Exploring the Experience of Living with and Managing Presbyopia.

SIGNIFICANCE: Presbyopia typically occurs around 40 years of age and affects approximately one-quarter of the global population. Up to October 2021, there were no approved pharmacotherapies for presbyopia, and common treatments, such as glasses, can have disadvantages for individuals' health-related quality of life. PURPOSE: This study aimed to document the experience of living with and managing presbyopia, identify perspectives on treatment options, and determine whether there is an unmet need in the treatment landscape. METHODS: Coded transcripts of concept elicitation (CE; n = 20) and cognitive debriefing (n = 20) interviews with presbyopic individuals, originally conducted for development of patient-reported outcome instruments, were reanalyzed to identify salient concepts describing participants' experiences with presbyopia treatments. Qualitative ranking exercises assessed participants' preferences for a potential pharmacotherapy vs. existing treatments. RESULTS: Because most concepts were identified with the CE interviews, data reflect CE findings unless otherwise noted. Average age across CE/cognitive debriefing interviews was 49.4 years; a vast majority of participants used glasses for presbyopia treatment. Four themes related to treatment with glasses were identified with the interviews: inconvenience during daily activities, negative physical sensations around the eyes/head, limitations, and undesirable impacts on daily life (e.g., psychosocial). Most commonly, participants reported inconveniences related to forgetting glasses and psychosocial impacts (e.g., feeling/looking older). Strained/tired eyes and limited ability to see at varying distances were also reported. Among participants with near-vision glasses who provided data, two-thirds expressed interest in alternative treatments. In addition, almost three-quarters of the participants ranked hypothetical eye drops as their first or second preferred option, vs. reading glasses, contact lenses, magnifying glasses, and surgery. CONCLUSIONS: This study explored the experience of living with and managing presbyopia and identified limitations and negative impacts of current treatments. Pharmacological development (e.g., eye drops) may fulfill an unmet need in the presbyopia treatment landscape.

[TREATMENTS FOR PRESBYOPIA].

INTRODUCTION: Presbyopia is the physiological, gradual, progressive loss of the ability to see clearly at near point which affects people as they age. It is primarily caused by the thickening and stiffening of the lens leading to an inability to adjust its shape to become convex enough to induce adequate plus power to see at short distances. Symptoms usually begin affecting individuals around 40 years of age, the most common being discomfort in or around the eyes after prolonged near work, blur at distance after near work, and eventually progressing to near blur, often with a natural tendency to distance the object by holding it farther away to try to see it better. At a certain point near tasks become impossible and the patient will seek an external solution. Various therapies are available and being developed to treat presbyopia, which include glasses, contact lenses, intraocular lens implants, corneal laser procedures, intracorneal implants, scleral alterations and pharmacological ocular drops. Untreated presbyopia negatively affects quality of life as well as the world productivity since presbyopia progresses from approximately an age when people are still an active part of the workforce. As the population and life expectancy grow, so will the number of presbyopes. This article will discuss the various options available to treat presbyopia.

Digitized mini optofluidic element and its application to ophthalmic lenses for presbyopia correction.

Using the internally placed elastic membrane and multi-chamber configuration, we designed a digitized mini optofluidic element for fast switching between refractive and diffractive states of preset optical powers. Relief surface was used in the diffractive state. We applied finite element analysis to establish membrane mechanical characteristics for switching at the force level produced by the ocular elements such as ciliary muscle or lower eyelid at eye downgaze. The prototypes were made to demonstrate proof-of-concept. Membrane conformance to the diffractive grooves and imaging quality were demonstrated. The analysis supported switching under the force level exerted by the ocular elements supporting the digitized optofluidic element potential for presbyopia correction by ophthalmic lenses.

Subjective Evaluation of Defocus and Astigmatism Combinations Using Image Simulation in Presbyopes.

SIGNIFICANCE: Image simulation is a useful and efficient tool to explore the impact of defocus and astigmatism combinations on visual acuity and image quality score when accommodation is taken into account. PURPOSE: The goal of this experiment was to determine if a simulation is able to predict visual acuity and image quality score (IQS) with defocus and astigmatism combinations in presbyopes. METHODS: We measured visual acuity and IQS in five defocus and astigmatism combinations in either real or simulated conditions. In real conditions, the subjects viewed a stimulus through an ophthalmic lens or a deformable mirror. In simulated conditions, subjects viewed images of the same stimulus with simulated blur. The amounts of defocus and astigmatism combinations of a progressive addition lens in near vision were generated through a static correction of the subject's aberrations. We simulated three levels of accommodation: subject could not accommodate (FOC0), subject could accommodate to the less hyperopic focal point (FOC1), or subject could accommodate to the circle of least confusion (FOC2). RESULTS: Visual acuity or IQS did not differ between mirror and progressive addition lens conditions. Visual acuity measured in real blur conditions differed significantly from that in FOC0 simulated blur condition but were similar to that in FOC1 and FOC2 simulated blur conditions. Image quality score obtained in real conditions were between scores measured with the FOC0 and FOC1 simulated conditions, suggesting that the subjects were able to produce a low level of accommodation. CONCLUSIONS: Accommodation may play a role when comparing optical and simulated defocus and astigmatism combinations. Presbyopic subjects are able to produce a low level of accommodation that may counterbalance a part of the deleterious effect of the astigmatism on image quality. Simulation remains a useful tool if the correct accommodation state is taken into account.

Computer vision syndrome in presbyopic digital device workers and progressive lens design.

PURPOSE: To estimate the prevalence of computer vision syndrome (CVS) in presbyopic digital device workers using two ophthalmic progressive lens designs during the working day, and to analyse the association of CVS with sociodemographic, occupational, digital device exposure and refractive factors. METHODS: This time series, quasi-experimental design study included 69 presbyopic digital device workers (age range: 46-69 years; mean ± SD = 54.7 ± 5.0). All used desktop computers at their workplace. Progressive addition lenses (PALs) and occupational lenses were used for three months each. CVS was measured with the CVS-Q© questionnaire before intervention (baseline) and at 1 week, 1 month and 3 months after wearing the lenses. A multivariate logistic regression model was used to identify the factors that were associated with an improved CVS-Q© score. RESULTS: 37.7% of the subjects were female and 78.3% were ametropes; 65.2% had advanced presbyopia. 56.2% used digital devices at work >6 h day-1 . The prevalence of CVS at baseline, after wearing PALs for three months and after three months of occupational lens wear was 68.1%, 33.3% and 18.8%, respectively. The mean CVS-Q© score was lower with occupational lenses than with PALs (p = 0.001). 40.6% of the digital device workers improved their CVS-Q© score ≥2 points with the occupational lenses. Ametropes were less likely than emmetropes to improve with occupational lenses (OR = 0.27, p = 0.05). 89.8% of the sample workers were satisfied or very satisfied with the occupational lenses and 71% were similarly satisfied with the PALs. 73.9% chose the occupational lenses as their first choice of lens for digital device use, compared with 17.4% for PALs. CONCLUSIONS: Computer vision syndrome is reduced in presbyopic desktop computer workers wearing occupational lenses compared with PALs, especially in emmetropes.

Large area liquid crystal lenses for correction of presbyopia.

Presbyopia is the failure of the eye lens to accommodate. The widely used presbyopia correction method involves wearing bi/trifocal or progressive glasses, which limits the field of view due to division of lens area into sections of different optical power. A large aperture focus tunable liquid crystal lens has the potential to correct human eye accommodation failure and provide a wide field of view. In this paper, we present characterization and demonstration of a segmented phase profile liquid crystal lens, which has the characteristics of a large area (diameter: 20 mm), being flat and thin (<2 mm), and having continuous focus tunability (1.5 D to 0 D), fast response time (<500 ms), low operating voltage (<5 V), and on-axis diffraction-limited performance (for a 5mm aperture). Considering all these properties, our lens provides performance details of an approach for presbyopia correction. We have tested the minimum resolution and visual acuity of 20 subjects using the designed lens and compared the results with a reference glass lens of the same optical power.

Unmet need for presbyopia correction and its associated factors among school teachers in Hawassa city, South Ethiopia.

BACKGROUND: Presbyopia is a decline in the amplitude of accommodation with the onset in the age range 40-45 years affecting near visual task performance. As the age of presbyopia onset coincides with productive age, it results in great productivity loss especially in those with high near visual demand like teachers. A maximum near vision potential is essential for teachers in ensuring the quality of education, as most of the students' evaluations and scripts are assessed manually in Ethiopia. The prevalence of unmet need for presbyopia correction among school teachers ranges from 38.5-70.4% worldwide. Though presbyopia is a common ocular condition, there is limited evidence regarding the unmet need for presbyopia correction in Ethiopia as well as in Hawassa city. Therefore, this study aimed to determine the magnitude of unmet need for presbyopia correction and its associated factors among school teachers in Hawassa city, South Ethiopia. METHODS: A school-based cross-sectional study was conducted among teachers older than 35 years. A simple random sampling technique was used to select participants using name lists as a sampling frame from 69 schools. The participants selected underwent for distance and near visual acuity test. Those with distance visual acuity of 6/12 or worse were refracted before near visual acuity test. Information on the spectacle use and associated factors was obtained using the interviewer-administered questionnaire. Data analysis was done using Statistical Package for Social Sciences software version 20. Binary logistic regression analysis was performed to assess association between independent variables and the unmet need for presbyopia correction. RESULTS: A total of 459 study participants were included in the study with a response rate of 95.21%.The unmet need for presbyopia correction was 51.26% (95%CI: 46.7-55.6%). Female gender (AOR = 2.50; 95%CI: 1.51-4.15), age 36-45 (AOR = 4.12; 95%CI: 1.46-11.76), unaware of presbyopia (AOR = 2.36; 95%CI: 1.2-4.66) and self-rating of current vision as good (AOR = 3.5; 95%CI: 1.61-7.6) were factors significantly associated with the unmet need for presbyopia. CONCLUSIONS: The burden of unmet need for presbyopia correction is a moderate priority according to the World Health Organization for presbyopia correction services criteria. A school-based presbyopia awareness creation program is important to reduce this huge burden.

Presbyopia Correction Using Multifocal Soft Contact Lenses in Patients With Monofocal Intraocular Lenses.

OBJECTIVES: To investigate the effectiveness of presbyopia correction using multifocal soft contact lenses (MF SCLs) for pseudophakic subjects with monofocal intraocular lenses (IOLs). METHODS: In 11 subjects, after monofocal IOL implantation, disposable MF SCLs (Dailies Total 1 Multifocal, Alcon) were daily used for 3 months. Binocular visual acuity between 0.3 and 5 m was measured using an all-distance vision tester (AS-15, Kowa) at 1 and 3 months and compared before and during MF SCL wear. Binocular contrast sensitivity testing was conducted under mesopic and photopic illuminations at 1 month. RESULTS: The mean manifest refraction spherical equivalent before MF SCL wear was -0.36 D. The add powers of used MF SCLs were +1.25, +2.00, and +2.50 D in 1, 16, and 5 eyes, respectively. The mean binocular visual acuities during MF SCL wear were 20/20 or better between 0.5 and 5 m and significantly improved at 0.7 m or less (P<0.025). There was no change in the mesopic contrast sensitivity, whereas the photopic contrast sensitivity at 18 cycles per degree was degraded during MF SCL wear. CONCLUSIONS: The use of MF SCL was effective for presbyopia correction in pseudophakic subjects with monofocal IOL, and favorable binocular vision would be obtained in a range from distance to intermediate.

Adaptive eyeglasses for presbyopia correction: an original variable-focus technology.

We propose an original variable-focus technology specially designed for presbyopia-correcting adaptive eyeglasses. It has been thought through to offer vision comfort without cutting on aesthetics. It relies on a fluid-filled variable-focus lens (presenting 2 liquids and 1 ultra-thin membrane) assisted by a low-power, high-volume microfluidic actuator. It also features a distance-sensing system to provide automatic focusing. We demonstrate the qualities of this novel technology on our first prototype. Our prototype achieves the necessary 3-diopter-high power variation on a 20-millimeter-wide variable zone with low actuation pressures (~200 Pa at most), and the preliminary optical quality analysis shows the spatial resolution is much better than the one specified by classic eye charts. We discuss further improvements in terms of optics, aesthetics and portability. In particular, we point out that this variable technology is compatible with standard base curves, and we highlight an optimal configuration where the power consumption of our opto-fluidic engine is about 25 mW peak.

Small-aperture strategies for the correction of presbyopia.

PURPOSE OF REVIEW: The recent scientific literature provides evidence of long-term results with small-aperture corneal inlays, as well as new evidence from a multicenter postmarket study of small-aperture intraocular lenses (IOLs) and early reports of the use of topical agents for presbyopia correction through pupil constriction. The field of small-aperture optics is growing and changing rapidly. RECENT FINDINGS: This article reviews what is known to date about various small-aperture optics platforms, including a posterior chamber IOL, add on device, corneal inlay, contact lenses, and pupil-constricting drops. Additionally, the impact of small-aperture technologies on light perception and visual performance, as well as the relative merits of monocular versus binocular small apertures are discussed. SUMMARY: Small-aperture optics are a dynamic, physiologic solution to the problem of presbyopia. They are effective throughout the range of accommodation loss and in pseudophakia. Small-aperture optics offer an opportunity to improve vision in presbyopes with and without cataracts. In some forms, they may also be able to reduce the impact of aberrations or improve vision in eyes with corneal irregularities, scars, or iris damage.

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.