Monovision Correction Research Articles

Efficacy of small incision lenticule extraction combined with femtosecond laser-assisted in situ keratomileusis for optimized monovision correction in myopia patients with presbyopia

Objective: To evaluate the efficacy of optimized monovision correction using small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) in myopic patients with presbyopia and to assess the corneal epithelial remodeling following these procedures. Methods: A prospective study was conducted. Thirty-two patients (64 eyes) with myopia and presbyopia who underwent surgical correction at Chongqing Bai Ji Eye Clinic from August 2021 to April 2023 were continuously included. There were 9 males and 23 females, with an average age of (44.25±2.96) years. The dominant eyes (32 eyes) underwent SMILE, while the non-dominant eyes (32 eyes) underwent FS-LASIK with mild myopia and partial negative spherical aberration induction. Data on visual acuity and refraction were collected preoperatively and at 1 week, 1 month, 3 months, and 6 months postoperatively. Total ocular aberrations were measured using the iProfiler Plus, and the corneal epithelial thickness in different regions was assessed using anterior segment optical coherence tomography. Safety and efficacy indices were calculated based on visual acuity, the defocus and contrast sensitivity were measured using the Binoptometer 4P binocular vision tester, and a patient satisfaction survey was performed. Results: At 1 week postoperatively, the uncorrected distance visual acuity (UDVA) of dominant eyes significantly improved compared to preoperative values. At 3 months postoperatively, the uncorrected near visual acuity (UNVA) of non-dominant eyes showed significant improvement (P<0.05), 96.9% (31 eyes) of the dominant eyes achieved UDVA of 1.0 or better, and 93.8% (30 eyes) of the non-dominant eyes achieved UNVA of 0.8 or better. The safety index for distance vision was 1.15±0.09, and the efficacy index was 1.15±0.11. At 1 week, 1 month, 3 months, and 6 months postoperatively, the proportion of dominant eyes with a spherical equivalent (SE) deviation within ±0.50 D of the target was 90.6% (29 eyes), 90.6% (29 eyes), 93.8% (30 eyes), and 96.2% (31 eyes), respectively; for non-dominant eyes, the corresponding proportions were 81.3% (26 eyes), 87.5% (28 eyes), 93.8% (30 eyes), and 96.2% (31 eyes). The postoperative spherical aberration was (0.11±0.03) μm for dominant eyes and (-0.01±0.04) μm for non-dominant eyes, showing a statistically significant difference (P<0.05). At 1 week and 1 month postoperatively, the central corneal epithelial thickness of non-dominant eyes was significantly higher than that of dominant eyes [(71.34±21.69) μm vs. (51.97±6.33) μm at 1 week, and (61.34±15.85) μm vs. (52.72±6.32) μm at 1 month; P<0.05]. Patient satisfaction was high, with 96.9% (31 patients) rating their satisfaction as "satisfactory" or higher. Conclusions: The combined use of SMILE and FS-LASIK for optimized monovision correction in myopic patients with presbyopia is both safe and effective, achieving high postoperative satisfaction. The SMILE procedure reduces the extent of corneal epithelial remodeling compared to FS-LASIK.

Ocular Dominance and Its Association With Central Corneal Thickness: An Observational Study in Central India.

Background The aim of this study is to determine ocular dominance and its association with central corneal thickness (CCT). These two parameters are of great significance in clinical practice; identifying the dominant eyehelpsin planning cataract surgeries, treatment of presbyopia, monovision correction, etc., and assessing the CCT helps inearly diagnosis and management of keratoconus, glaucoma, contact lens-related complications, and dry eye. Methods A cross-sectional study that involvespatients and volunteers who have come for a checkup to the ophthalmology department of the college hospital. Ninety patients were examined for this study within two months. The hole-in-card test is performed to determine the ocular dominance in people with normal and healthy eyes without any pathologies except refractive errors. Specular microscopy through a non-contact modality will be done to assess thethickness of the central cornea in both eyes. Statistical analysis was done using the paired t-test to compare the patient's eyes and the chi-square test, which helps usassociate ocular dominance and CCT. Results Right eye dominance was seen in the majority of the participants (72.91%), whereas left eye dominance was seen in comparatively fewer participants (27.08%). The CCT of the dominant eye is found to be 520.40± 29.83μm and that of the non-dominant eye is 524.40± 29.37μm. A lower CCT in the dominant eye was seen in 83.33% of the subjects; 14.58% of them had a higher CCT in the dominant eye and 2.08% had the same CCT in both eyes. Conclusion From the observational study that has been made, the majority of the population shows right eye dominance. The CCT is relatively thinner in the dominant eye. About 80-85%of the examined people showed a thinner cornea in the dominant eye. But we cannot generalize that the eye with a lessercorneal thickness will be the dominant eye in all the cases, as a few cases have shown dominance in the eye with a thicker cornea.

Case report of the evidence of a spontaneous Reverse Pulfrich effect in monovision after cataract surgery

BackgroundCataracts affect the optics of the eye in terms of absorption, blur, and scattering. When cataracts are unilateral, they cause differences between the eyes that can produce visual discomfort and harm binocular vision. These interocular differences can also induce differences in the processing speed of the eyes that may cause a spontaneous Pulfrich effect, a visual illusion provoking important depth misperceptions. Interocular differences in light level, like those present in unilateral cataracts, can cause the Classic Pulfrich effect, and interocular differences in blur, like those present in monovision, a common correction for presbyopia, can cause the Reverse Pulfrich effect. The visual system may be able to adapt, or not, to the new optical condition, depending on the degree of the cataract and the magnitude of the monovision correction.Case presentationHere, we report a unique case of a 45-year-old patient that underwent unilateral cataract surgery resulting in a monovision correction of 2.5 diopters (D): left eye emmetropic after the surgery compensated with a monofocal intraocular lens and right eye myopic with a spherical equivalent of -2.50 D. This patient suffered severe symptoms in binocular vision, which can be explained by a spontaneous Pulfrich effect (a delay measured of 4.82 ms, that could be eliminated with a 0.19 optical density filter). After removing the monovision with clear lens extraction in the second eye, symptoms disappeared. We demonstrate that, at least in this patient, both Classic and Reverse Pulfrich effects coexist after unilateral cataract surgery and that can be readapted by reverting the interocular differences. Besides, we report that the adaptation/readaptation process to the Reverse Pulfrich effect happens in a timeframe of weeks, as opposed to the Classic Pulfrich effect, known to have timeframes of days. Additionally, we used the illusion measured in the laboratory to quantify the relevance of the spontaneous Pulfrich effect in different visual scenarios and tasks, using geometrical models and optic flow algorithms.ConclusionsMeasuring the different versions of the Pulfrich effect might help to understand the visual discomfort reported by many patients after cataract surgery or with monovision and could guide compensation or intervention strategies.

Multifocal versus modified monovision corrections: A non-dispensing comparison of visual assessment in presbyopic neophytes.

To compare the visual performance of two simultaneous-vision soft multifocal contact lenses and to compare multifocal contact lens and its modified monovision counterpart in presbyopic neophytes. A double-masked, prospective, comparative study was conducted on 19 participants fitted with soft PureVision2 multifocal (PVMF) and clariti multifocal (CMF) lenses in random order. High- and low-contrast distance visual acuity, near visual acuity, stereopsis, contrast sensitivity, and glare acuity were measured. The measurements were conducted using multifocal and modified monovision design with one brand and then repeated with another brand of lens. High-contrast distance visual acuity showed a significant difference between CMF (0.00 [-0.10-0.04]) and PureVision2 modified monovision (PVMMV; -0.10 [-0.14-0.00]) correction (P = 0.003) and also between CMF and clariti modified monovision (CMMV; -0.10 [-0.20-0.00]) correction (P = 0.002). Both modified monovision lenses outperformed CMF. The current study did not show any statistically significant difference between contact lens corrections for low-contrast visual acuity, near visual acuity, and contrast sensitivity (P > 0.01). Stereopsis at near distance was significantly lower with both modified monovision (PVMMV: 70 [50-85]; P = 0.007, CMMV: 70 [70-100]; P = 0.006) and with CMF (50 [40-70]; P = 0.005) when compared to spectacles (50 [30-70]). Glare acuity was significantly lower with multifocal (PVMF: 0.46 [0.40-0.50]; P = 0.001, CMF: 0.40 [0.40-0.46]; P = 0.007) compared with spectacles (0.40 [0.30-0.40]), but no significant difference was noted between the multifocal contact lenses (P = 0.033). Modified monovision provided superior high-contrast vision compared to multifocal correction. Multifocal corrections performed better for stereopsis when compared to modified monovision. In parameters like low-contrast visual acuity, near acuity, and contrast sensitivity, both the corrections performed similarly. Both multifocal designs showed comparable visual performances.

Commentary: Leap forward in presbyopia management - Correcting beyond spectacles.

Commentary: Leap forward in presbyopia management - Correcting beyond spectacles.

Monovision Correction Preference and Eye Dominance Measurements.

To propose new methods for eye selection in presbyopic monovision corrections. Twenty subjects with presbyopia performed two standard methods of binary eye dominance identification (sensory with +1.50 diopters [D ]and +0.50 D and sighting with "hole-in-the-card") and two psychophysical methods of perceived visual quality: (1) the Preferential test, 26 natural images were judged with the near addition in one eye or in the other in a 2-interval forced-choice task, and the Eye Dominance Strength (EDS) defined as the proportion of trials where one monovision is preferred over the other; (2) the Multifocal Acceptance Score (MAS-2EV) test, the perceived quality of a natural images set (for 2 luminance levels and distances) was scored and EDS defined as the score difference between monovision in one eye or the other. Left-eye and right-eye dominance are indicated with negative and positive values, respectively. Tests were performed using a Simultaneous Vision Simulator, which allows rapid changes between corrections. Standard sensory and sighting dominances matched in only 55% of subjects. The Preferential EDS (ranging from -0.7 to +0.9) and MAS-2EV EDS (ranging from -0.6 to +0.4) were highly correlated. Selecting the eye for far in monovision with the MAS-2EV, sensory, or sighting tests would have resulted in 79%, 64%, and 43% success considering the Preferential test as the gold standard. Tests based on perceptual preference allow selection of the preferred monovision correction and measurement of dominance strength. The binocular visual simulator allows efficient implementation of eye preference tests for monovision in clinical use.

Spatial Interactions in Interocular and Monocular "Blur Suppression".

The suppression of blurred images in one eye by clear images in the other eye is thought to contribute to the success of monovision correction. We show that interocular suppression occurs also for low-contrast targets that are not blurred and, to a lesser extent, when clear and low-contrast targets are presented to the same eye. A blurred target presented to one eye may be suppressed when a clear target is presented to the other eye. We sought to determine how this interocular suppression varies according to the separation between the blurred and clear targets and the magnitude of imposed blur. In addition, we examined whether a similar suppression occurs when the clear and blurred targets are imaged in the same eye. Subjects (N = 4) viewed a clear 20/40 Sloan letter surrounded by four 2 × 10 min-arc flanking bars. In different blocks of trials, the gap between the letter and flanking bars varied from 0.5 to 4 bar widths. In addition, the flanking bars were either clear or spatially filtered to simulate 0.5 to 2 D of blur. The contrast required to detect the flanking bars was determined when the letter and flanking bars were presented either dichoptically or monoptically and compared with the thresholds for the bar targets presented alone. In both dichoptic and monoptic viewing conditions, detection thresholds for the blurred flanking bars are highest for the smallest spatial gap and decrease systematically as the gap increases. Thresholds are uniformly higher during dichoptic than monocular viewing, but the proportional change with the bar-to-letter separation is similar in both conditions. Surprisingly, the magnitude of imposed blur has very little influence on the magnitude of threshold elevation in either the dichoptic or monoptic viewing conditions. Because threshold elevation is nearly the same in the presence of 0 to 2 D of blur, we prefer to designate the phenomenon we studied as "contrast suppression." The similar spatial characteristics of suppression during dichoptic and monoptic viewing are consistent with contributions from a common neural mechanism.

Effect of interocular differences on binocular visual performance after inducing forward scattering

PurposeTo assess binocular visual performance by means of binocular summation on visual function after inducing monocular forward scattering, and to study the influence of interocular differences on ocular parameters.MethodsSeven young healthy subjects were recruited. Four Bangerter foils and five fog filters were used to induce monocular forward scattering. To analyse the impact of the scatter, visual acuity, contrast sensitivity, visual discrimination capacity and distance stereoacuity were measured binocularly with the filter placed over the dominant eye. Additionally, interocular differences were calculated for four ocular parameters: the Objective Scatter Index (OSI), Strehl ratio (SR), modulation transfer function cut‐off (MTF cut off) and straylight (log[s]). Binocular summation was determined for these visual functions.ResultsA statistically significant deterioration in visual acuity, contrast sensitivity and stereoacuity was seen for all of the filter conditions with respect to the natural state (baseline), with the largest change being recorded for the Bangerter foils. Similarly, the interocular difference for the three retinal image quality parameters (OSI, SR and MTF cut‐off) and log(s) increased significantly for the Bangerter foil condition, but not for the fog filters (except log(s)). Binocular summation declined gradually with the Bangerter foils, but not for the fog filters. Statistically significant correlations were found, that is, the greater the interocular differences, the lower the binocular summation of the visual functions and the greater the distance stereoacuity.ConclusionIncreased forward scattering in the dominant eye resulted in interocular differences, which reduced the overall binocular visual performance, including the binocular summation of several visual functions and distance stereoacuity. The results suggest that marked interocular differences in ocular parameters should be avoided in cases of ocular pathology, amblyopia and emmetropisation procedures (such as refractive surgery) or a monovision correction for presbyopia.

Not dominance but the loss of binocularity determines the success of monovision

Purpose: To determine whether ocular dominance strength influences success of monovision Design: Single-center, prospective, double blind crossover. Subjects received contact lenses with reading addition added to the left eye in the first trial period and to the right eye in the second period so that the type of monovision was randomized and blinded for the test subject and the investigator. Methods: 17 presbyopic subjects, aged 50-65, received conventional and crossed monovision, each for 2 weeks. Satisfaction, stereopsis (TNO, Titmus) and Snellen visual acuity were measured. Ocular dominance was examined according to Haidinger and +1D test. Results: Pearson correlation coefficient between strength of ocular dominance and subject satisfaction was ρ=0.088 for the conventional and ρ=0.000 for the crossed group. 93% of subjects were most satisfied with the type of monovision that yielded the highest Titmus score. For the TNO test this was only 64%. A statistical significant interaction effect was shown for this relationship (ρ=0.019). Conclusion: A significant correlation between dominance strength, refraction error and satisfaction could not be found. However, we observed that the highest stereopsis score according to the Titmus test was more likely to yield a higher satisfaction when comparing conventional and crossed monovision. When a physician opts for monovision correction, the Titmus test can be performed with test spectacles or contact lenses to decide which eye should be corrected for distance vision. The choice should be in favor of the correction that yields the best Titmus score.

Not dominance but the loss of binocularity determines the success of monovision

Purpose: To determine whether ocular dominance strength influences success of monovision Design: Single-center, prospective, double blind crossover. Subjects received contact lenses with reading addition added to the left eye in the first trial period and to the right eye in the second period so that the type of monovision was randomized and blinded for the test subject and the investigator. Methods: 17 presbyopic subjects, aged 50-65, received conventional and crossed monovision, each for 2 weeks. Satisfaction, stereopsis (TNO, Titmus) and Snellen visual acuity were measured. Ocular dominance was examined according to Haidinger and +1D test. Results: Pearson correlation coefficient between strength of ocular dominance and subject satisfaction was ρ=0.088 for the conventional and ρ=0.000 for the crossed group. 93% of subjects were most satisfied with the type of monovision that yielded the highest Titmus score. For the TNO test this was only 64%. A statistical significant interaction effect was shown for this relationship (ρ=0.019). Conclusion: A significant correlation between dominance strength, refraction error and satisfaction could not be found. However, we observed that the highest stereopsis score according to the Titmus test was more likely to yield a higher satisfaction when comparing conventional and crossed monovision. When a physician opts for monovision correction, the Titmus test can be performed with test spectacles or contact lenses to decide which eye should be corrected for distance vision. The choice should be in favor of the correction that yields the best Titmus score.

Contact lenses, the reverse Pulfrich effect, and anti-Pulfrich monovision corrections

Interocular differences in image blur can cause processing speed differences that lead to dramatic misperceptions of the distance and three-dimensional direction of moving objects. This recently discovered illusion—the reverse Pulfrich effect—is caused by optical conditions induced by monovision, a common correction for presbyopia. Fortunately, anti-Pulfrich monovision corrections, which darken the blurring lens, can eliminate the illusion for many viewing conditions. However, the reverse Pulfrich effect and the efficacy of anti-Pulfrich corrections have been demonstrated only with trial lenses. This situation should be addressed, for clinical and scientific reasons. First, it is important to replicate these effects with contact lenses, the most common method for delivering monovision. Second, trial lenses of different powers, unlike contacts, can cause large magnification differences between the eyes. To confidently attribute the reverse Pulfrich effect to interocular optical blur differences, and to ensure that previously reported effect sizes are reliable, one must control for magnification. Here, in a within-observer study with five separate experiments, we demonstrate that (1) contact lenses and trial lenses induce indistinguishable reverse Pulfrich effects, (2) anti-Pulfrich corrections are equally effective when induced by contact and trial lenses, and (3) magnification differences do not cause or impact the Pulfrich effect.

Impact of monovision on dynamic accommodation of early presbyopes

To examine the impact of monovision on dynamic changes in accommodation, pupil responses, spherical aberration and resultant image quality in early presbyopes. Refractive state, pupil size and spherical aberration levels were monitored in nine early presbyopes who exhibited some accommodation (40-50years, mean=42±2.37years) using a Shack-Hartmann aberrometer as a binocularly viewed stimulus stepped closer (from 2m to 40cm), or farther (from 40cm to 2m). Comparison data from two fully presbyopic (i.e. non-accommodating) subjects (ages 46 and 61years) and two young adults (ages 26 and 29years) were also collected. Each subject was fit with four different refractive strategies: (1) both eyes corrected for 2m, (2) both eyes corrected for 40cm, (3) monovision with the measured right eye corrected for 2m and, (4) monovision with the right eye corrected for 40cm. Monochromatic image quality was quantified using the AreaMTF metric. When fit with monovision, the largest number of early presbyopes produce an accommodative response dominated by the right eye correction (distance or near) as the stimulus is abruptly changed from the retinal conjugate plane of one eye to that of the other eye. However, the accommodative responses in some early presbyopes were always dominated by the distance corrected eye, the near corrected eye, or by convergence. When the stimulus approached, the near corrected eye experienced high image quality only if there was no accommodative response. However, reduced image quality was observed if an accommodative response was initiated. Neither accommodation nor pupil response latencies were longer with monovision corrections compared with bilateral distance corrections (p>0.05). In the early presbyopes, spherical aberration was reduced during near viewing, but primarily due to pupil miosis and not lens shape changes. As the stimulus was abruptly changed from the retinal conjugate plane of the distance corrected eye to that of the near corrected eye, most early presbyopes fit with monovision accommodated, which resulted in a decline, not an increase in image quality in the near corrected eye. These results reveal a non-optimal accommodative strategy in early presbyopes fit with monovision.

Evaluation of A Marketed Silicone Hydrogel Spherical Lens Used for Monovision Correction of Presbyopia

Evaluation of A Marketed Silicone Hydrogel Spherical Lens Used for Monovision Correction of Presbyopia

Vision with different presbyopia corrections simulated with a portable binocular visual simulator.

Presbyopes can choose today among different corrections to provide them with functional vision at far and near, and the outcomes and patient satisfaction depend on the selection. In this study, we present a binocular and portable vision simulator, based on temporal multiplexing of two synchronized tunable lenses allowing see-through and programmable visual simulations of presbyopic corrections. Seventeen binocular corrections were tested: 3 Monofocal (Far, Intermediate, Near), 4 Simultaneous Vision (bifocal, trifocal), 2 Monovision (far and near in either eye) and 8 Modified Monovision corrections (Simultaneous vision in one eye, Monofocal in the other eye). Perceived visual quality was assessed through the simulated corrections in 8 cyclopleged subjects who viewed a composite realistic visual scene with high contrast letters and a landscape at far (4 m) and a high contrast text at intermediate (66 cm) and near (33 cm) distances. Perceptual scores were obtained on a scale of 0 to 5 (low to high perceived quality). Perceptual preference was assessed by judging 36 random image pairs (6 repetitions) viewed through 9 binocular presbyopic corrections using two-interval forced choice procedures. The average score, across far and near distances, was the highest for Monovision (4.4±0.3), followed by Modified Monovision (3.4±0.1), Simultaneous Vision (3.0±0.1) and Monofocal corrections (2.9±0.2). However, the mean difference between far and near was lower for Simultaneous Vision and Monovision (0.4±0.1 PS) than Modified Monovision (1.8±0.7) or monofocal corrections (3.3±1.5). A strong significant correlation was found between the perceptual scores and the percentages of energy in focus, for each correction and distance (R = 0.64, p<0.0001). Multivariate ANOVA revealed significant influence of observation distances (p<10–9) and patients (p = 0.01) on Perceptual Score. In conclusion, we have developed a binocular portable vision simulator that can simulate rapidly and non-invasively different combinations of presbyopic corrections. This tool has applications in systematic clinical evaluation of presbyopia corrections.

Monovision and the Misperception of Motion

Monovision is a common prescription lens correction for presbyopia [1]. Each eye is corrected for a different distance, causing one image to be blurrier than the other. Millions of people have monovision corrections, but little is known about how interocular blur differences affect motion perception. Here, we report that blur differences cause a previously unknown motion illusion that makes people dramatically misperceive the distance and three-dimensional direction of moving objects. The effect occurs because the blurry and sharp images are processed at different speeds. For moving objects, the mismatch in processing speed causes a neural disparity, which results in the misperceptions. A variant of a 100-year-old stereo-motion phenomenon called the Pulfrich effect [2], the illusion poses an apparent paradox: blur reduces contrast, and contrast reductions are known to cause neural processing delays [3-6], but our results indicate that blurry images are processed milliseconds more quickly. We resolve the paradox with known properties of the early visual system, show that the misperceptions can be severe enough to impact public safety, and demonstrate that the misperceptions can be eliminated with novel combinations of non-invasive ophthalmic interventions. The fact that substantial perceptual errors are caused by millisecond differences in processing speed highlights the exquisite temporal calibration required for accurate perceptual estimation. The motion illusion-the reverse Pulfrich effect-and the paradigm we use to measure it should help reveal how optical and image properties impact temporal processing, an important but understudied issue in vision and visual neuroscience.

Monovision LASIK in emmetropic presbyopic patients.

BackgroundTo evaluate the efficacy and patient satisfaction of laser in situ keratomileusis (LASIK) monovision correction in presbyopic emmetropic patients.MethodsA retrospective review of 294 patients who underwent LASIK for monovision was conducted. All patients had preoperative uncorrected distance visual acuity in each eye of 20/25 or better in both eyes and underwent primary LASIK treatment in one eye with a near target; 82 patients underwent surgery in the distant eye for hypermetropia. Patients completed a patient-reported-outcome questionnaire at their one-month postoperative visit. Analysis was performed on a per patient basis with a logistic regression model.ResultsPatients achieved a postoperative mean spherical equivalent of −0.05 diopters (D) in the distant eye and −1.92 D in the near eye. Prior to surgery, 64.7% (n=178) of patients reported they were satisfied or very satisfied with their vision; postoperatively, this increased to 85.4% (n=251). The greatest predictor of dissatisfaction after surgery was severe patient-reported visual phenomena (glare, halos, starbursts, ghosting) (odds ratio 1.18, P=0.001).ConclusionsLASIK monovision for presbyopic patients with low refractive error and good preoperative uncorrected distance visual acuity is both safe and effective with high patient satisfaction. Patients who were dissatisfied in the postoperative period tended to be those with postoperative visual symptoms.

Revisiting monovision for presbyopia.

Presbyopia is an inevitable age-related loss of accommodation that results in spectacle dependence with common everyday near-vision tasks. Many surgical approaches to presbyopic correction have been investigated, with monovision correction being amongst the most common and attractive options. In this article, we will review the advantages and disadvantages of the new modalities of presbyopic monovision correction. New methods such as mini-monovision, corneal inlays, and multifocal corneal ablation aim to maximize stereopsis and decrease the anisometropic side effects of conventional monovision. These include inlays such as the KAMRA and Raindrop, and phakic intraocular lenses such as the hole ICL. Newer corneal laser refractive procedures such as small incision lenticule extraction have also shown good outcomes with monovision. Pseudophakic monovision using standard monofocal lenses still provides good results. Monovision for presbyopic correction continues to provide promising results. There are a number of new devices and techniques that have shown good visual acuity outcomes, patient satisfaction and spectacle independence.

Visual performance assessment of multifocal soft contact lenses vs. monovision using defocus curves

Purpose: To investigate the use of area-of-focus metrics to characterize the visual performance of nelfilcon A multifocal contact lenses compared with monovision correction in a population of established presbyopes.

Does monovision affect eye movement pattern during reading?

Purpose: Monovision is a successful approach to presbyopia in contact lens (CL) wearers but it may cause stress to the visual system. Visual stress was investigated by examining the impact of monovision correction on reading behaviour through eye movement recordings.

Presbyopia monovision correction and cortical adaptation.

The article “Immediate cortical adaption in visual and non-visual areas functions induced by monovision” approaches adaptation to monovision with contact lenses, one way of compensating the loss of near vision that affects all humans with ageing. This article is protected by copyright. All rights reserved