Ocular Straylight with Different Multifocal Contact Lenses

BCLA CLEAR Presbyopia: Management with contact lenses and spectacles

This paper seeks to outline the history, market situation, clinical management and product performance related to the correction of presbyopia with both contact lenses and spectacles. The history of the development of various optical forms of presbyopic correction are reviewed, and an overview is presented of the current market status of contact lenses and spectacles. Clinical considerations in the fitting and aftercare of presbyopic contact lens and spectacle lens wearers are presented, with general recommendations for best practice. Current options for contact lens correction of presbyopia include soft simultaneous, rigid translating and rigid simultaneous designs, in addition to monovision. Spectacle options include single vision lenses, bifocal lenses and a range of progressive addition lenses. The comparative performance of both contact lens and spectacle lens options is presented. With a significant proportion of the global population now being presbyopic, this overview is particularly timely and is designed to act as a guide for researchers, industry and eyecare practitioners alike.

Effect of the chromaticity of stimuli on night vision disturbances

The perception of halos and other night vision disturbances is a common complaint in clinical practice. Such visual disturbances must be assessed in order to fully characterize each patient's visual performance, which is particularly relevant when carrying out a range of daily tasks. Visual problems are usually assessed using achromatic stimuli, yet the stimuli encountered in daily life have very different chromaticities. Hence, it is important to assess the effect of the chromaticity of visual stimuli on night vision disturbances. The aim of this work is to study the influence of the chromaticity of different visual stimuli on night vision disturbances by analyzing straylight and visual discrimination under low-light conditions. For that, we assessed the monocular and binocular visual discrimination of 27 subjects under low illumination using the Halo test. The subjects' visual discrimination was assessed after exposure to different visual stimuli: achromatic, red, green, and blue, both at the monitor's maximum luminance and maintaining the same luminance value for the different visual stimuli. Monocular straylight was also measured for an achromatic, red, green, and blue stimuli. The blue stimulus had the greatest effect on halos in both monocular and binocular conditions. Visual discrimination was similar for the red, green, and achromatic stimuli, but worsened at lower luminance. The greatest influence of straylight was observed for the blue stimulus. In addition, visual discrimination correlated with straylight measurements for achromatic stimuli, wherein greater straylight values correlated with an increased perception of halos and other visual disturbances.

Intraocular Straylight and Multifocal Soft Contact Lens Fit With a Myopia Control Approach

OBJECTIVES

Center-distance multifocal contact lenses (MFCLs) are used to slow myopia progression. We examined the effect of two MFCLs on intraocular straylight values in myopic individuals.

METHODS

Twenty-five young myopic adults were enrolled and were fit with three contact lenses (Biofinity sphere, Biofinity Multifocal, and NaturalVue Multifocal) in a random order over two study visits. Pupil size (NeurOptics VIP-300, Laguna Hills, CA) and contact lens centration were measured. Right eye intraocular straylight measurements were collected (OCULUS C-Quant; Wetzlar, Germany) and compared with a spectacle trial lens. Log straylight (LogSL) values and straylight residuals were analyzed using repeated-measures analyses of variance with Tukey-corrected post hoc t -tests.

RESULTS

The mean participant age (±SD) was 24.1±1.5 years, and right eye spherical equivalent refractive error was -3.38±1.53 DS. There was no difference in mesopic pupil size between visits ( P =0.68) and no difference in contact lens centration between lenses ( P =0.99). LogSL values differed by lens type ( P =0.004). LogSL with the spectacle trial lens was significantly greater than with each contact lens type (all P <0.05), but there were no significant differences in LogSL between the three contact lenses (all P >0.05). There was no difference between the three contact lens designs for straylight residuals ( P =0.33).

CONCLUSIONS

Measured intraocular straylight for both MFCLs was not different than with a spherical soft contact lens. A significant increase in intraocular straylight with spectacle trial lens correction was observed compared with all contact lenses.

Silicone hydrogel versus hydrogel soft contact lenses for differences in patient-reported eye comfort and safety

BACKGROUND

Ocular discomfort is the leading cause of permanent discontinuation of soft contact lens (SCL) wear. Silicone hydrogel and hydrogel materials are the two major categories of SCLs, with silicone hydrogel materials being newer and more breathable than hydrogel materials. Whether comfort is associated with SCL material is controversial despite numerous studies. Similarly, the difference between these materials in terms of safety outcomes (e.g. frequency of microbial keratitis) is unclear.

OBJECTIVES

To evaluate the comparative effectiveness and safety of silicone hydrogel compared with hydrogel SCLs on self-reported comfort, dry eye test results, and adverse events in SCL-wearing adults 18 years of age or older.

SEARCH METHODS

The Cochrane Eyes and Vision Information Specialist searched the electronic databases for randomized controlled trials (RCTs). There were no restrictions on language or date of publication. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, including the Cochrane Eyes and Vision Trials Register; 2022, Issue 6), MEDLINE Ovid, Embase.com, PubMed, LILACS (Latin American and Caribbean Health Science Information database), ClinicalTrials.gov, and World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We also searched the reference lists of identified studies, review articles, and guidelines for information about relevant studies that may not have been identified by our search strategy. Furthermore, we contacted investigators regarding ongoing trials. The most recent database search was conducted on 24 June 2022.

SELECTION CRITERIA

Our search selection criteria included RCTs, quasi-RCTs, and cross-over RCTs.

DATA COLLECTION AND ANALYSIS

We applied standard Cochrane methodology.

MAIN RESULTS

We included seven parallel-group RCTs conducted in the USA, the UK, Australia, Germany, India, and Turkey. A total of 1371 participants were randomized. The duration of SCL wear ranged from one to 52 weeks. Study characteristics and risk of bias The median number of participants per trial was 120 (interquartile range: 51 to 314), and the average age ranged from 20.7 to 33.0 years. Women represented the majority of participants (range 55% to 74.9%; 5 RCTs). Collectively, the included trials compared eight different silicone hydrogel SCLs with three different hydrogel SCLs. Five trials compared daily disposable SCLs, and two compared extended wear SCLs (worn for seven days and six nights). New SCL wearers were enrolled in three trials. Two trials included both new and established SCL wearers, and two trials did not report participants' history of SCL use. Five trials were sponsored by industry. We judged the overall risk of bias to be 'high' or 'some concerns' for the safety and efficacy outcomes. Findings One trial reported Ocular Surface Disease Index (OSDI) results, with the evidence being very uncertain about the effects of SCL material on OSDI scores (mean difference -1.20, 95% confidence interval [CI] -10.49 to 8.09; 1 RCT, 47 participants; very low certainty evidence). Three trials reported visual analog scale comfort score results, with no clear difference in comfort between materials, but the evidence was of very low certainty; trial results could not be combined because the three trials reported results at different time points. The evidence is very uncertain about the effect of SCL material on discontinuation of contact lens wear (risk ratio [RR] 0.64, 95% CI 0.11 to 3.74; 1 RCT, 248 participants). None of the included trials reported Contact Lens Dry Eye Questionnaire (CLDEQ-8) or Standard Patient Evaluation of Eye Dryness (SPEED) scores. There was no evidence of a clinically meaningful difference (> 0.5 unit) between daily disposable silicone hydrogel and hydrogel SCLs in corneal staining, conjunctival staining, or conjunctival redness (very low certainty evidence). Adverse events Very low certainty evidence from two trials comparing daily disposable SCLs suggested no evidence of a difference between lens materials in the risk of vision-threatening adverse events at one to four weeks (RR 0.68, 95% CI 0.08 to 5.51; 2 RCTs, 368 participants). Two trials comparing extended wear SCLs indicated that hydrogel SCLs may have a 2.03 times lower risk of adverse events at 52 weeks compared with silicone hydrogel SCLs (RR 2.03, 95% CI 1.38 to 2.99; 815 participants), but the certainty of evidence was very low.

AUTHORS' CONCLUSIONS

The overall evidence for a difference between all included silicone hydrogel and hydrogel SCLs was of very low certainty, with most trials at high overall risk of bias. The majority of studies did not assess comfort using a validated instrument. There was insufficient evidence to support recommending one SCL material over the other. For extended wear, hydrogel SCL may have a lower risk of adverse events at 52 weeks compared to silicon hydrogel. Future well-designed trials are needed to generate high certainty evidence to further clarify differences in SCL material comfort and safety.

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

Purpose

To 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.

Methods

Seven 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.

Results

A 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.

Conclusion

Increased 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.

Visual performance after the deterioration of retinal image quality: induced forward scattering using Bangerter foils and fog filters

We induced and evaluated different levels of retinal-image degradation using Bangerter foils and fog filters. We found increased straylight and an important deterioration in visual performance, assessed by means of visual acuity, contrast threshold, and visual discrimination capacity. Bangerter foils induced forward scattering levels comparable to those observed in mature to severe cataracts, with an important impact of halos and starbursts. Fog filters induced lower levels of intraocular scattering, although luminous veils and circular halos were reported. The visual disturbance index positively correlated with intraocular scattering and straylight. Our results show retinal-image quality has an important influence on night-vision performance.

Clinical performance of presbyopia correction with a multifocal corneoscleral lens

AIM

To assess the clinical performance of a multifocal corneoscleral lens for the presbyopia correction.

METHODS

A prospective clinical trial of the Onefit™ A multifocal corneoscleral lens was conducted with 40 participants with presbyopia. At 4wk of continuous wear of the corneoscleral lens, changes in the distance, intermediate, and near visual acuity (VA) were evaluated. The safety of the corneoscleral lens, central corneal thickness (CCT), corneal endothelial cell count, binocular stereopsis, tear film break-up time (BUT), corneal staining, corneal edema, corneal neovascularization (NV), and conjunctival hyperemia were examined. In addition, a subjective questionnaire addressing satisfaction (rated from 1 to 5 points) and discomfort (rated from 1 to 5 points) was administered.

RESULTS

Forty participants were enrolled in this study. Six participants were excluded because of poor compliance with lens fitting (n=2) and loss to follow-up (n=4). The mean age of the participants was 53.0±4.9y. At 4wk of continuous wear of the corneoscleral lens, the best corrected far, intermediate, and near VA was 0.08±0.11, 0.10±0.12, and 0.10±0.12 logMAR, respectively. These results were significant improvements over the baseline uncorrected VA (far: P=0.004; intermediate: P=0.004; near: P=0.002). CCT, corneal endothelial cell count, binocular stereopsis, BUT, corneal staining, corneal edema, corneal NV, and conjunctival hyperemia were not significantly different between baseline and after corneoscleral lens use. The average satisfaction scores for fit sensation; corrected far, intermediate, and near VA; and ease of handling were 4.1, 3.4, 3.6, 3.5, and 3.4, respectively. The average discomfort scores for dryness, irritation, foreign body sensation, redness, fogging, and halo were 1.7, 1.8, 1.5, 1.7, 1.7, and 1.3, respectively.

CONCLUSION

Far, intermediate, and near VA are improved in presbyopic patients with the multifocal corneoscleral lens compared to uncorrected baseline VA, without adverse ocular effects. This evidence supports the safety and effectiveness of presbyopia correction with multifocal corneoscleral lenses.

Straylight As The Result Of Refractive Correction

Purpose

To investigate the effect of refractive correction on straylight.

Patients and methods

Straylight values were measured with the C-Quant (Oculus Optikgeräte, GmbH, Wetzlar, Germany) in 1) near-emmetropic eyes (n=30) with various negative powered refractive lenses and in 2) myopic eyes (n=30) corrected with prescribed eyeglasses and contact lenses. The straylight measurements in each group were compared in the different conditions.

Results

In the near-emmetropic group, a significant effect (p<0.001) of each added negative diopter was found to increase straylight values with 0.006 log-units. In the second group, no significant correlation with type of correcting lens was found on straylight values.

Conclusion

Refractive correction with high minus power (contact) lenses result in subtle increase of straylight values. These changes are relatively small and do not lead to visual disability in a clinical setting.

Presbyopia: Effectiveness of correction strategies

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