AcrySof Natural SN60AT versus AcrySof SA60AT intraocular lens in patients with color vision defects

The Effects of a Blue-Light Filtering Versus Clear Intraocular Implant on Color Appearance

Purpose

More than a dozen studies have investigated whether blue-light filtering (BLF) intraocular lens (IOL) implants influence color vision, generally finding they do not. These studies have not tested color vision per se; rather, they have measured color vision deficiencies or chromatic discrimination. Here, we used additive trichromatic colorimetry to assess color appearance in participants with BLF and clear IOL.

Methods

Seventy-six participants were recruited from two populations: older participants (n = 52) with BLF and clear IOL (n = 98 eyes; M = 67.33 ± 7.48 years; 58.8% female; 25.5% non-White), and young adult control participants (n = 24; M = 21.0 ± 5.13 years; 70.8% female; 41.5% non-White). Participants used a custom-built tricolorimeter to mix three primaries until a perceived perfect neutral white was achieved. Color appearance, expressed as chromaticity coordinates, was measured with a spectral radiometer (ILS950).

Results

Between subjects, the BLF IOL chromaticity coordinates (x = 0.34, y = 0.35, u′ = 0.21, v′ = 0.48) were not significantly different from the clear IOL (x = 0.34, y = 0.33, u′ = 0.22, v′ = 0.48). BLF and clear IOL were also not different within-contralateral subjects (n = 21; BLF x = 0.34, y = 0.33, u′ = 0.22, v′ = 0.47; clear x = 0.34, y = 0.33, u′ = 0.21, v′ = 0.48). Both IOL groups differed from young adults (v′[0.45; P = 0.001], x[0.31; P = 0.008], and y[ 0.30, P < 0.000], but not u′[0.21]).

Conclusions

One advantage of geometric representation of color space is the ability to specify the appearance (rather than spectral composition) of any light mixture by specific coordinates. Using this system, only minor differences in color appearance were found between a BLF, clear IOL, and young natural lens.

Translational Relevance

When color perception is directly measured, the BLF and clear IOL are not meaningfully different.

Effect of blue-blocking lenses on colour discrimination

CLINICAL RELEVANCE

Tinted lenses may adversely affect colour discrimination. Before recommending tinted lenses to patients, practitioners should bear in mind any effects on colour discrimination. The effects of 'blue-blocking' spectacle lenses with high luminous transmittance on colour vision is not a concern.

BACKGROUND

Blue-blocking lenses have been widely promoted by manufacturers and practitioners. The more blue-blocking lenses are known to affect colour vision significantly but there has been no study of the effects of 'blue-blocking' spectacle lenses.

METHODS

The transmittances of commercially available lenses were measured and the three lenses with the lowest blue light transmittance were selected. Subjects undertook the following computer-based colour vision tests: Colour Assessment and Diagnosis; the Cambridge Colour Test; and the Farnsworth-Munsell 100 Hue Test.

RESULTS

Blue and luminous transmittances of lenses were documented. The reduction in blue transmittance varied from 12 to 40 per cent (two to 30 per cent compared with an untinted lens). The lenses were found to have no significant, statistical or possibly practical, effect on the results of the three colour vision tests (t-test, analysis of variance, Mann-Whitney, Kruskal-Wallis).

CONCLUSION

The modest blue light transmittance reduction of the 'blue-blocking' spectacle lenses examined was not sufficient to have a statistically significant effect on colour vision.

Blue-light filtering intraocular lenses (IOLs) for protecting macular health

BACKGROUND

An intraocular lens (IOL) is a synthetic lens that is surgically implanted within the eye following removal of the crystalline lens, during cataract surgery. While all modern IOLs attenuate the transmission of ultra-violet (UV) light, some IOLs, called blue-blocking or blue-light filtering IOLs, also reduce short-wavelength visible light transmission. The rationale for blue-light filtering IOLs derives primarily from cell culture and animal studies, which suggest that short-wavelength visible light can induce retinal photoxicity. Blue-light filtering IOLs have been suggested to impart retinal protection and potentially prevent the development and progression of age-related macular degeneration (AMD). We sought to investigate the evidence relating to these suggested benefits of blue-light filtering IOLs, and to consider any potential adverse effects.

OBJECTIVES

To assess the effects of blue-light filtering IOLs compared with non-blue-light filtering IOLs, with respect to providing protection to macular health and function.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2017, Issue 9); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and the ICTRP. The date of the search was 25 October 2017.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), involving adult participants undergoing cataract extraction, where a blue-light filtering IOL was compared with an equivalent non-blue-light filtering IOL.

DATA COLLECTION AND ANALYSIS

The prespecified primary outcome was the change in distance best-corrected visual acuity (BCVA), as a continuous outcome, between baseline and 12 months of follow-up. Prespecified secondary outcomes included postoperative contrast sensitivity, colour discrimination, macular pigment optical density (MPOD), proportion of eyes with a pathological finding at the macula (including, but not limited to the development or progression of AMD, or both), daytime alertness, reaction time and patient satisfaction. We evaluated findings related to ocular and systemic adverse effects.Two review authors independently screened abstracts and full-text articles, extracted data from eligible RCTs and judged the risk of bias using the Cochrane tool. We reached a consensus on any disagreements by discussion. Where appropriate, we pooled data relating to outcomes and used random-effects or fixed-effect models for the meta-analyses. We summarised the overall certainty of the evidence using GRADE.

MAIN RESULTS

We included 51 RCTs from 17 different countries, although most studies either did not report relevant outcomes, or provided data in a format that could not be extracted. Together, the included studies considered the outcomes of IOL implantation in over 5000 eyes. The number of participants ranged from 13 to 300, and the follow-up period ranged from one month to five years. Only two of the studies had a trial registry record and no studies referred to a published protocol. We did not judge any of the studies to have a low risk of bias in all seven domains. We judged approximately two-thirds of the studies to have a high risk of bias in domains relating to 'blinding of participants and personnel' (performance bias) and 'blinding of outcome assessment' (detection bias).We found with moderate certainty, that distance BCVA with a blue-light filtering IOL, at six to 18 months postoperatively, and measured in logMAR, was not clearly different to distance BCVA with a non-blue-light filtering IOL (mean difference (MD) -0.01 logMAR, 95% confidence interval (CI) -0.03 to 0.02, P = 0.48; 2 studies, 131 eyes).There was very low-certainty evidence relating to any potential inter-intervention difference for the proportion of eyes that developed late-stage AMD at three years of follow-up, or any stage of AMD at one year of follow-up, as data derived from one trial and two trials respectively, and there were no events in either IOL intervention group, for either outcome. There was very low-certainty evidence for the outcome for the proportion of participants who lost 15 or more letters of distance BCVA at six months of follow-up; two trials that considered a total of 63 eyes reported no events, in either IOL intervention group.There were no relevant, combinable data available for outcomes relating to the effect on contrast sensitivity at six months, the proportion of eyes with a measurable loss of colour discrimination from baseline at six months, or the proportion of participants with adverse events with a probable causal link with the study interventions after six months.We were unable to draw reliable conclusions on the relative equivalence or superiority of blue-light filtering IOLs versus non-blue-light filtering IOLs in relation to longer-term effects on macular health. We were also not able to determine with any certainty whether blue-light filtering IOLs have any significant effects on MPOD, contrast sensitivity, colour discrimination, daytime alertness, reaction time or patient satisfaction, relative to non-blue-light filtering IOLs.

AUTHORS' CONCLUSIONS

This systematic review shows with moderate certainty that there is no clinically meaningful difference in short-term BCVA with the two types of IOLs. Further, based upon available data, these findings suggest that there is no clinically meaningful difference in short-term contrast sensitivity with the two interventions, although there was a low level of certainty for this outcome due to a small number of included studies and their inherent risk of bias. Based upon current, best-available research evidence, it is unclear whether blue-light filtering IOLs preserve macular health or alter risks associated with the development and progression of AMD, or both. Further research is required to fully understand the effects of blue-light filtering IOLs for providing protection to macular health and function.

Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses

Introduction

The purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material.

Methods

Monocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions.

Results

No difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found.

Conclusion

Blue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

Ultraviolet or blue-filtering intraocular lenses: what is the evidence?

Cataract surgery was revolutionised by the introduction of modern intraocular lenses in the late 1940's. By the late 1960's to 1970's evidence had emerged that short-wavelength light caused phototoxicity at the retina and retinal pigment epithelium. By the early 1980's ultraviolet filters had been incorporated into intraocular lenses. This caused intense controversy, as there was concern that the UV-filtering chromophore might leach out into the eye causing toxicity. With the arrival of blue-filtering intraocular lenses (BFIOLs) in 1990's, a further debate was ignited as to their safety and potential disadvantages. Selecting the optimal performing intraocular lens to obtain the best visual performance with the fewest potential drawbacks has become complex and challenging for cataract surgeons and their patients with the wide choice of lenses available. Choosing a personalised lens to address astigmatism, presbyopia, spherical aberration, chromatic aberration, and potentially to shield the retina from short-wavelength light is now possible. The potential benefits and possible side effects of these different innovations emphasise the importance of assessing the evidence for their clinical utility, allowing the surgeon and the patient to weigh-up the risk benefit ratio and make an informed decision. The BFIOLs were developed to reduce cyanopsia, address chromatic aberration, and improve contrast sensitivity in different lighting conditions, as well as to prevent short-wavelength light reaching the retina thus potentially reducing the risk of developing age-related macular degeneration. Further design development of the BFIOLs was to mimic the natural crystalline lens absorption and transmittance properties in adulthood. Multiple publications have reported on the potential benefits and pitfalls of implanting a blue-filtering lens. The potential disadvantages raised in the literature over the last 25 years since their introduction, regarding compromise of visual function and disruption of the circadian system, have been largely dispelled. The clear benefits of protecting the retina from short-wavelength light make a BFIOLs a sensible choice. The purpose of this article presented at the Cambridge symposium 2015 is to review the literature on this subject.

Effect on contrast sensitivity after clear, yellow and orange intraocular lens implantation

The objective of this study is to evaluate contrast sensitivity function (CSF) after clear, yellow- and orange-tinted intraocular lens (IOL) implantation. This was a prospective randomized study of 98 patients with senile cataract for a period of 6 months from day 1 of August 2014 to day 31 of January 2015. After phacoemulsification, 33 patients were implanted with clear IOLs (AcrySof UV-filtering IOL, SA60AT), 32 patients were implanted with yellow coloured IOLs (AcrySof Natural blue-light-attenuating and UV-filtering IOL, SN60AT with IMPRUV(®) filter) and 33 patients were implanted with orange-tinted blue-filtering IOLs (PC440Y Optech). After 1 month, monocular CSF was done under photopic (85 cd/m(2)) and mesopic (3 cd/m(2)) illumination condition with CSV-1000 test. The best corrected visual acuity (BCVA) after 1 month was 0.021 ± 0.058 logMAR for clear lens, 0.022 ± 0.059 logMAR for yellow lens and 0.019 ± 0.065 logMAR for orange lens (p = 0.989). Uniocular average photopic contrast sensitivity was 1.36 ± 0.19, 1.43 ± 0.18 and 1.46 ± 0.15 log units for clear lens, yellow lens and orange lens, respectively (statistically not significant; p = 0.076). Average mesopic contrast sensitivity was 1.02 ± 0.21 log units for clear lens, 1.00 ± 0.17 log units for yellow lens and 0.99 ± 0.15 log units for orange lens (statistically not significant; p = 0.771). Yellow or orange coloured blue-filtering IOLs are comparable to clear IOLs in terms of photopic and mesopic contrast sensitivity.

Recent studies provide an updated clinical perspective on blue light-filtering IOLs

Background

Recent reviews of blue light-filtering intraocular lenses (IOLs) have stated their potential risks for scotopic vision and circadian photoentrainment. Some authors have challenged the rationale for retinal photoprotection that these IOLs might provide. Our objective is to address these issues by providing an updated clinical perspective based on the results of the most recent studies.

Methods

This article evaluates the currently available published papers assessing the potential risks and benefits of blue light-filtering IOLs. It summarizes the results of seven clinical and two computational studies on photoreception, and several studies related to retinal photoprotection, all of which were not available in the previous reviews. These results provide a clinical risk/benefit analysis for an updated review for these IOLs.

Results

Most clinical studies comparing IOLs with and without the blue light-filtering feature have found no difference in clinical performance for; visual acuity, contrast sensitivity, color vision, or glare. For blue light-filtering IOLs, three comparative clinical studies have shown improved contrast sensitivity and glare reduction; but one study, while it showed satisfactory overall color perception, demonstrated some compromise in mesopic comparative blue color discrimination. Comparative results of two recent clinical studies have also shown improved performance for simulated driving under glare conditions and reduced glare disability, better heterochromatic contrast threshold, and faster recovery from photostress for blue light-filtering IOLs. Two computational and five clinical studies found no difference in performance between IOLs with or without blue light-filtration for scotopic vision performance and photo entrainment of the circadian rhythm. The rationale for protection of the pseudophakic retina against phototoxicity is discussed with supporting results of the most recent computational, in-vitro, animal, clinical, and epidemiological investigations.

Conclusions

This analysis provides an updated clinical perspective which suggests the selection of blue light-filtering IOLs for patients of any age, but especially for pediatric and presbyopic lens exchange patients with a longer pseudophakic life. Without clinically substantiated potential risks, these patients should experience the benefit of overall better quality of vision, reduced glare disability at least in some conditions, and better protection against retinal phototoxicity and its associated potential risk for AMD.

Electronic supplementary material

The online version of this article (doi:10.1007/s00417-011-1697-6) contains supplementary material, which is available to authorized users.

Effect of yellow-tinted intraocular lenses on short-wavelength automated perimetry

PURPOSE

To investigate the effect of yellow-tinted intraocular lenses (IOLs) on short-wavelength automated perimetry (SWAP).

DESIGN

Cross-sectional observation study.

METHODS

Twenty-two patients who had implantation of yellow-tinted IOLs (AcrySof SN60AT or SN60WF; Alcon Laboratories) in 1 eye and nontinted IOLs (AcrySof SA60AT) in the other eye were included in the study. Standard automated perimetry (SAP) and SWAP were performed. The results for the mean deviation (MD), pattern standard deviation (PSD), and glaucoma hemifield test results were compared intra-individually.

RESULTS

There was no statistically significant difference between the IOLs on the SAP (MD, PSD; P = .851, P = .388, respectively). However, a significant difference was observed between the IOLs on the SWAP (MD, PSD; P = .033, P = .033, respectively). The glaucoma hemifield test did not show significant differences in the SAP (P = .083). However, the SWAP showed significant differences (P = .003).

CONCLUSIONS

The yellow-tinted IOLs may affect the results of the SWAP; therefore, caution is needed in interpreting the results of the SWAP in eyes with implanted yellow-tinted IOLs.

Blue-blocking IOLs: a complete review of the literature

Intraocular lenses (IOLs) that block both ultraviolet and blue wavelength light (<500 nm)were introduced in the 1990s. Since then, the potential benefits and harm from blocking blue light has been debated. We report the results of a complete review of all peer-reviewed published studies regarding the impact of blocking the transmission of blue light. Fifty-six published reports on subjects related to blue-blocking lenses including sleep disturbance, visual outcomes, cataract surgery, lens transmittance, sunlight exposure, and macular disease were found in peer reviewed journals from 1962 to 2009. Eleven reports specifically compared visual outcomes between blue-blocking IOLs and nonblue-locking IOLs. Of these, 10 independent studies (10/11, 91%) concluded that there are no significant effects of blue-blocking IOLs on various meters of visual performance including visual acuity, contrast sensitivity, color perception, and photopic, mesopic, and scotopic sensitivities. Only one group of authors reported that the use of blue-blocking IOLs may have detrimental effects on scotopic vision and circadian rhythms. However, the actual clinical significance of these potential negative effects on scotopic vision and on sleep patterns is uncertain. The benefits of blocking the transmission of blue light to the macula and the relationship between progression of age-related macular degeneration remain unclear. However, the published studies clearly state that the use of blue-blocking IOLs is not detrimental in visual acuity, color perception, and contrast sensitivity. The reported potential negative effects on scotopic vision and sleep disturbance appear to be minimal and may not be clinically relevant. (Surv Ophthalmol 55:284--289, 2010. 2010 Elsevier Inc. All rights reserved.)

Effect of a blue-light-blocking intraocular lens on the quality of sleep

PURPOSE

To evaluate whether implantation of a blue-light-blocking intraocular lens (IOL) affects sleep quality.

SETTING

Repatriation General Hospital, Adelaide, Australia.

METHODS

This study comprised patients who had bilateral cataract surgery during the preceding 12 months with implantation of a conventional SI40NB IOL or an AcrySof Natural SN60WF blue-light-blocking IOL. Patients were contacted by telephone at least 6 months after second-eye surgery, and the Pittsburgh Sleep Quality Index (PSQI) questionnaire was administered. Results were compared between groups.

RESULTS

Of the 49 patients, 31 received conventional IOLs and 18, blue-light-blocking IOLs. The mean age of the patients was 80 years +/- 8.1 (SD). The median PSQI score was 6 (interquartile range 3 to 8). There were no statistically significant differences in PSQI scores between the 2 IOL groups (P = .65). This remained true after adjustment for sex, age, medication, and time since surgery.

CONCLUSION

The blue-light-blocking IOL had no effect on the sleep quality of patients, indicating that these IOLs might serve as an alternative to conventional IOLs without a detrimental effect on circadian rhythm.

Effect of a yellow intraocular lens on scotopic vision, glare disability, and blue color perception

PURPOSE

To compare the photopic and scotopic contrast sensitivity with and without glare as well as blue color perception between eyes with an AcrySof SN60AT Natural intraocular lens (IOL) (Alcon Laboratories Inc.) and eyes with a conventional AcrySof SA60AT IOL.

SETTING

Ankara University School of Medicine, Department of Ophthalmology, Ankara, Turkey.

METHODS

Right eyes of 38 patients with an AcrySof Natural IOL and right eyes of 38 age-matched patients with a conventional AcrySof SA60AT IOL were included in a study. Contrast sensitivity was measured with the Functional Acuity Contrast Test under photopic conditions. Scotopic contrast sensitivity in the presence or absence of glare was measured using the Mesotest II (Oculus GmbH). Blue-green color vision was evaluated with the Moreland equation of the HMC Anomaloskop MR (Oculus GmbH).

RESULTS

The mean age of patients was 66.6 years +/- 8.2 (SD) in the Natural IOL group and 66.4 +/- 8.0 years in the conventional IOL group. There was no statistically significant difference in photopic contrast sensitivity, scotopic contrast sensitivity with and without glare, or disability glare between the 2 groups (P>.05). Photopic and scotopic contrast sensitivity with and without glare significantly decreased with age in both groups (P<.01). There was no statistically significant difference in anomaloscope scores between the 2 groups (P>.05). The Moreland middle match point showed a significant shift toward blue with age in both groups (P<.01).

CONCLUSIONS

The AcrySof SN60AT Natural IOL provided contrast sensitivity under photopic and scotopic conditions (with and without glare) and blue color perception comparable that obtained with the AcrySof SA60AT IOL. Scotopic vision and blue color discrimination decreased with age with both IOLs.

Surgical findings with the tinted AcrySof intraocular lens in children

INTRODUCTION

The AcrySof foldable acrylic intraocular lens (IOL) has become an accepted and frequent means of treating pediatric aphakia. A new version of this lens with blue-light filtering properties purports to offer superior retinal protection. We describe our experience with this tinted lens and compare it to findings with the standard, nontinted IOL.

METHODS

A chart review identified 29 eyes of 21 children (tinted lens group; age 11 months to 13 years) who had the tinted IOL implanted. The standard lens group consisted of 38 eyes (31 patients; age 11 months to 15 years). Most eyes had an intact posterior capsule at the time of implantation.

RESULTS

The incidence of postoperative inflammation was fairly high in both groups (71% in the tinted lens group, 60% in the standard lens group). The tinted lens group showed a higher incidence of transient inflammation than the standard lens group (p=0.03) but the rates of nontransient sequelae (posterior synechiae, iris synechiae, membranes formation, capsule, or IOL opacification) were similar (66% versus 47%; p=0.11). Posterior capsule opacification occurred in 15 eyes in the tinted lens group and 16 eyes in the standard lens group (p=0.15) but was visually significant in only 10 and 11 eyes, respectively (p=0.77).

CONCLUSIONS

Transient inflammation is higher with implantation of tinted versus nontinted IOLs, but long-term inflammatory sequelae are roughly equal, as is the rate of posterior capsule opacification. The question as to whether the chromophore in the tinted lens caused the higher incidence of transient inflammation is unresolved.

Comparison of visual function following implantation of Acrysof Natural intraocular lenses with conventional intraocular lenses

BACKGROUND

Recently an intraocular lens (IOL) has been introduced which blocks blue light. As blocking blue light may be to the patient's detriment, this study was designed to evaluate visual function following implantation of a blue-blocking (Acrysof Natural) IOL.

METHODS

Patients were recruited for this non-randomized controlled interventional study, from those attending a private rural ophthalmology clinic for cataract surgery (n = 93). Only those who had previously had a conventional IOL implanted into one eye were offered an Acrysof Natural IOL for the second eye. Postoperatively patients underwent refracted Snellen visual acuity, contrast sensitivity using a CSV-1000E instrument and colour vision testing using a Farnsworth D-15 test, with a subset (n = 20) undergoing a Farnsworth-Munsell 100-Hue test. Results were then compared between eyes. Finally, a subset (n = 63) completed a survey designed to assess the subjective impact of the Acrysof Natural IOL.

RESULTS

There were no statistically significant differences between eyes implanted with conventional IOLs compared with Acrysof Natural IOLs for visual acuity (t = 0.57; P = 0.57), contrast sensitivity (t = 0.43; P = 0.67 for 3 cycles per degree [cpd], t = 0.56; P = 0.58 for 6 cpd, t = 0.09; P = 0.93 for 12 cpd and t = 0.16; P = 0.87 for 18 cpd) or colour vision with the Farnsworth D-15 (Chi(2) = 0.38; P = 0.55) or the Farnsworth-Munsell 100-Hue test t = 0.34; P = 0.74). Most subjects reported that they could not tell a difference between the two IOLs subjectively or that any difference experienced was not significant.

CONCLUSION

Our sample did not show any significant differences between eyes implanted with conventional IOLs and the Acrysof Natural IOL. We would suggest that the Acrysof Natural IOL may be used without any significant difference in visual function.