Blue-blocking Intraocular Lenses Research Articles

The Blue Light Hazard Versus Blue Light Hype

The blue light hazard is the experimental finding that blue light is highly toxic to the retina (photic retinopathy), in brief abnormally intense exposures, including sungazing or vitreoretinal endoillumination. This term has been misused commercially to suggest, falsely, that ambient environmental light exposure causes phototoxicity to the retina, leading to age-related macular degeneration (AMD). We analyze clinical, epidemiologic, and biophysical data regarding blue-filtering optical chromophores. Perspective. Analysis and integration of data regarding the blue light hazard and blue-blocking filters in ophthalmology and related disciplines. Large epidemiologic studies show that blue-blocking intraocular lenses (IOLs) do not decrease AMD risk or progression. Blue-filtering lenses cannot reduce disability glare because image and glare illumination are decreased in the same proportion. Blue light essential for optimal rod and retinal ganglion photoreception is decreased by progressive age-related crystalline lens yellowing, pupillary miosis, and rod and retinal ganglion photoreceptor degeneration. Healthful daily environmental blue light exposure decreases in older adults, especially women. Blue light is important in dim environments where inadequate illumination increases risk of falls and associated morbidities. The blue light hazard is misused as a marketing stratagem to alarm people into using spectacles and IOLs that restrict blue light. Blue light loss is permanent for pseudophakes with blue-blocking IOLs. Blue light hazard misrepresentation flourishes despite absence of proof that environmental light exposure or cataract surgery causes AMD or that IOL chromophores provide clinical protection. Blue-filtering chromophores suppress blue light critical for good mental and physical health and for optimal scotopic and mesopic vision.

Blue light filtering ophthalmic lenses: A systematic review

ABSTRACT Background: Blue blocking (BB) lenses, including spectacles and intraocular lenses, work by attenuating short-wavelength light. BB glasses are being marketed with the aim to reduce eye fatigue symptoms when using digital devices, improve sleep quality and potentially confer protection from retinal phototoxicity. BB intraocular lenses following cataract surgery may be implanted because they are thought to prevent age-related macular degeneration (AMD) progression. Methods: The present study is a systematic review aiming to analyze BB lenses clinical efficacy in preventing blue light-related ocular disorders, including AMD progression, eye fatigue, and their impact on sleep quality. We searched Medline, PubMed, Web of Science and the Cochrane Library until May 2020. Results:Although several studies have been performed investigating BB lenses, clinical efficacy for preventing or attenuating the above-mentioned ocular disorders is often theorical or based on laboratory or animal experiments. Conclusions: To date, there is a lack of consistent evidence for a larger-sclale introduction of BB lenses in the routine clinical practice.

Age affects intraocular lens attributes preference in cataract surgery.

PURPOSE:The aim of this study is to analyze the effects of age on intraocular lens (IOL) attributes preference.MATERIALS AND METHODS:We enrolled 4213 eyes that underwent smooth phacoemulsification and IOL implantation between January 2005 and June 2018. Patients were subdivided into six groups according to their ages, i.e.,≤40, 41–50, 51–60, 61–70, 71–80, and ≥ 81 years old. The difference in preference of IOL attributes regarding age, gender, and year of surgery was analyzed separately. The analyzed IOL attributes included asphericity, astigmatism-correction, presbyopia-correction, and blue-blocking function.RESULTS:The patients averaged 68.3 ± 11.6 years old at the time of surgery. There was no significant difference in age between males and females. There were 1980 patients (47.0%) selected aspheric IOL, 822 patients (19.5%) selected multifocal (MF) IOL, 93 patients (2.2%) selected toric IOL, and 859 patients (20.4%) selected blue-blocking IOL. Adoption of aspheric and MF IOL increased significantly during the study (P < 0.001 for both attributes). There were more young patients selected aspheric and MF IOL (P < 0.001 for both), and the change in the trend of adoption over the years was also most significant in the young group (P < 0.001 for both). The proportion of patients that selected blue-blocking IOL decreased significantly after 2011 (P < 0.001). There was no gender preference in aspheric, MF, and toric IOL selection. However, there were more male patients selected blue-blocking IOL (P = 0.018).CONCLUSION:The adoption of IOLs with emerging technologies increased significantly over the years. Younger adults tended to adopt advanced technology IOL more than the older ones.

The effect of blue-blocking and neutral intraocular lenses on circadian photoentrainment and sleep one year after cataract surgery.

To compare the long-term effect on circadian photoentrainment and sleep in patients implanted with neutral and blue-blocking intraocular lenses 1year after cataract surgery. Randomized, controlled trial involving 67 patients with age-related cataract. Intervention was cataract surgery with implantation of either a neutral or a blue-blocking intraocular lens (IOL). Main outcome was activation of the intrinsically photosensitive retinal ganglion cells (ipRGC) measured by chromatic pupillometry. The circadian rhythm was analysed by 24-hr melatonin profiles and actigraphy; the latter was also used to determine objective sleep quality. The Pittsburgh Sleep Quality Index determined subjective sleep quality. One year after surgery, peak melatonin concentration was 3.3pg/ml (95% CI, 2-5.5) corresponding to 50% lower for the participants allocated to blue-blocking IOLs compared with participants allocated to neutral IOLs. Compared with preoperative levels, the ipRGC response had increased by 13.7% (95% confidence interval [CI], 3.2-22.6) 1year after surgery. Objective sleep quality was also improved as the time of wakefulness after sleep onset had improved by 5min (95% CI, 1-10) for the entire population while sleep efficiency had increased by two percentage points (95% CI, 0.42-3.65) although exclusively, for the participants allocated to blue-blocking IOLs. Blue-blocking IOLs increased sleep efficiency but lowered nocturnal melatonin secretion compared with neutral IOLs. Cataract surgery improved the response of ipRGCs and sleep quality. However, the effect of cataract surgery on sleep quality may be unrelated to circadian photoentrainment.

The effect of blue-blocking intraocular lenses on circadian biological rhythm: protocol for a randomised controlled trial (CLOCK-IOL colour study)

IntroductionBlue light information plays an important role in synchronising internal biological rhythm within the external environment. Circadian misalignment is associated with the increased risk of sleep disturbance, obesity, diabetes mellitus,...

Ultraviolet-blocking intraocular lenses

Ultraviolet-blocking intraocular lenses (IOLs) are used routinely in cataract surgery and are widely accepted. Blue-blocking IOLs, however, have been much debated since their inception. In this article, we will review the advantages and disadvantages of blue-blocking IOLs. In experimental and animal studies, acute blue light exposure induces retinal damage and the use of blue-blocking IOLs lessens this damage. Many large epidemiologic studies have further investigated this relationship between blue light exposure and the development of age-related macular degeneration, and have shown conflicting results. Visual performance and circadian rhythm disturbances have also been explored in patients with blue-blocking IOLs; no significant negative effects have been shown. The current literature on blue-blocking IOLs is contradictory. Studies have failed to conclusively prove that blue-blocking lenses provide photoprotection against age-related macular degeneration or cause any significant detrimental effects on visual function or circadian rhythms.

New light for old eyes: comparing melanopsin-mediated non-visual benefits of blue-light and UV-blocking intraocular lenses

Background/aimsMelanopsin-expressing photosensitive retinal ganglion cells form a blue-light-sensitive non-visual system mediating diverse physiological effects including circadian entrainment and cognitive alertness. Reduced blue wavelength retinal illumination through cataract formation is thought...

Reply to letter from Mainster M.A. &amp; Turner P.L. titled “Blue light’s benefits vs blue-blocking intraocular lens chromophores”

Dear Editor, We are pleased to reply to the letter from Mainster and Turner concerning our review article [1]. We referred to “published” references [2, 3] by Mainster for his preference for violet-blocking intraocular lenses (IOLs). The quote which contradicts their viewpoint [4] is correctly attributed to the patent with Mainster as the principal inventor [5]. Any reader of the patent would reasonably surmise that the principal inventor would have accepted the quoted statements in the patent. AMO OptiBlue IOLs based on this patent were available to Mainster as he comparatively evaluated them [3]. The referred 1986 paper by Mainster suggested only an ideal short wavelength cut-off for 10% transmittance value, which can be met by many possible complete spectral transmittance curves, unlike the specific preference in the patent and his later papers [2, 3, 5]. Views by Mainster and Turner related to circadian rhythm photoentrainment, including unsubstantiated concerns for pediatric patients are in error, since they are based on computations using erroneously constructed action spectra with a peak of 460 nm as published by two investigators in 2001 before the discovery of intrinsically photosensitive retinal ganglion cells (ipRGC) in 2002 [1, 6]. In addition to ipRGC cells, additional contributions by medium wavelength cones as found in animal investigations are also supported by later independent measurement of the light-induced human melatonin suppression which gives a relatively broad peak from 460 to 500 nm [6, 7]. Lack of any concern for circadian photoentrainment for blue light-filtering IOLs, and its validation by the two human sleep studies, is summarized in our review article [1, 6]. Unlike their viewpoint [4] with glaring omissions, our review [1] discusses three scotopic clinical studies showing no clinically detectable disadvantage for blue light-filtering IOLs in scotopic conditions. In patients with early AMD, even with higher simulated blue-light filtering, timed performances of block manipulation by hand and ambulation by walking though two mobility courses under scotopic conditions was the same as for colorless IOLs [8]. While Mainster and Turner state photoreceptive benefits of colorless IOLs, there is no supporting clinical evidence. In addition, blue light-filtering IOLs have been confirmed to be safe in millions of pseudophakic patients since 2003. Their letter ignores the comparative glare study showing reduced effect of glare disability on simulated driving performance for blue light-filtering IOLs [9].We acknowledge the proof reading error in the Hammond et al. paper where the two bulbs were mislabeled in their figure 3 [10]. Our resultant erroneous sentence should be corrected to state that the Xenon glare source has relatively greater energy from shorter wavelength [1]. But this minor error does not at all affect the study’s scientific validity and key findings related to reduced glare disability, better heterochromatic contrast threshold, and faster recovery from photostress in eyes implanted with blue light-filtering IOLs [1, 10]. In addition, the target and glare sources need not be the same during the day, because natural outdoor backgrounds are more likely to be an atmospheric blue and targets are more likely to be mid-to-long wavelength [10].Their suggestion of wearing sunglasses in dazzling conditions is unrealistic at night to reduce glare or photostress effects while driving against an opposing lane of cars with Xenon headlights. Unlike their examination of selected epidemiological studies, we reviewed in-vitro, animal, clinical, and epidemiological studies related to photoprotection by blue light-filtering IOLs [1]. In summary, we did not find any validated risk for photoreception by blue light-filtering IOLs, while finding many investigations which suggest their benefits of creating better vision and reduced glare while protecting against retinal phototoxicity and its associated potential risk for AMD.

A possible strategy for implanting blue‐blocking intraocular lenses

Editor, Age-related macular degeneration (AMD) is said to be associated with sunlight exposure. This is supported by some epidemiological studies but not others. Epidemiological studies have also shown AMD progression following cataract surgery (Cuthbertson et al. 2009). Lipofuscin is considered a biomarker for cellular ageing and oxidative damage with one fluorophore A2E found in the retinal pigment epithelium (RPE) with peak sensitivity of short wavelength. It is thought to be an important mediator of AMD progression generating reactive oxygen species on photoexcitation and being phototoxic to RPE cells in culture (Algvere et al. 2006). Short wavelength light is absorbed by the ageing crystalline lens and this protective effect is lost following cataract surgery, likely resulting in cellular damage as a result (Algvere et al. 2006). Experimental studies showing the protective nature of a yellow intraocular lens (IOL) against radiation damage between 400 and 500 nm and the peak blue-light hazard of wavelengths at 435–440 nm (ICNIRP 1997) support this hypothesis (Cuthbertson et al. 2009). However the data is experimental and with conflicting evidence from epidemiological studies, the role of sunlight exposure in AMD remains inconclusive. In the 1980s, patients undergoing phacoemulsification surgery were given protection against radiation of wavelengths below 400 nm with clear UVR-blocking IOLs but not the blue-light hazard. Considering the experimental (Ham et al. 1976) and the epidemiological evidence that blue light induces damage in the retina, it is rational to implant a yellow IOL following phacoemulsification surgery, in patients at risk of AMD. However, early theoretical reports suggest yellow IOLs may have an effect on scotopic vision, reducing visual performance and contrast sensitivity when compared to a clear IOL due to blue light absorption. On the other hand, filtering out blue light improves the contrast on the retina in the sense that Rayleigh scattering in the vitreous is inversely proportional to the forth power of the wavelength. With foveal scotopic vision decreasing with age, the loss of blue light in the image caused by yellow IOLs may have an impact on night activities such as walking down stairs. Theoretical comparison between yellow IOLs and a middle aged crystalline lens indicated that the loss of blue light in the image may cause reduced scotopic sensitivity but this may not be clinically significant for scotopic vision and clinical trials with blue blocking IOLs have demonstrated no impact on contrast sensitivity (Cuthbertson et al. 2009). Blue light is said to have a role in the regulation of circadian rhythms which could affect sleep and lead to depression, although it is unclear how clinically relevant this is. Therefore, using clear IOLs with UV filters is also recommended over yellow IOLs further complicating the choice in IOL selection. Ideally, an IOL should have no effect on scotopic sensitivity and circadian rhythm with maximal protective effective against short wavelength phototoxicity. However, each of these scenarios has different peak wavelengths and therefore IOL selection will be a balance of these functions. Thus, clinical trials were not able to demonstrate a negative impact of blue blocking IOLs (Cuthbertson et al. 2009). However, if concern exists one option is to implant a clear IOL in one eye and a yellow IOL in the fellow eye. In a patient with bilateral asymmetrical AMD, we recommend that consideration should be given to implanting the yellow IOL in the eye with less severe disease to minimize AMD progression. The literature reports that most patients do not notice a problem with colour vision having a clear IOL in one eye and a yellow one in the other (Marshall et al. 2005; Algvere et al. 2006). There is only one case report of a patient who required explantation of the yellow IOL due to colour perception problems (Shah & Miller 2005). We anticipate this strategy will help minimize AMD progression and while preserving scotopic vision for patients undergoing cataract surgery if scotopic vision is an issue.

Practice patterns of Canadian Ophthalmological Society members in cataract surgery—2010 survey

Objective: To establish the cataract surgery practice patterns of the members of the Canadian Ophthalmological Society (COS). Study Design: Web-based questionnaire. Methods: In January 2010, an email with a link to SurveyMonkey was sent from the COS office to its 305 members who had indicated their practice focus is cataract surgery. A reminder email was sent 2 weeks later. All responses were collected anonymously. Results: There was a 32.5% response rate (99 responses), compared with 20.7% in 2009. Two respondents volunteered that they no longer performed cataract surgery and 1 response was incomplete; therefore, 96 responses were analyzed. The results of the 2010 survey were compared to those of the 2009 survey. Conclusions: While the majority of the practice patterns analyzed were unchanged between the 2009 and 2010 surveys, there appears to be a trend to start nonsteroidal anti-inflammatory drug eye drops earlier preoperatively and an increase in the use of one-piece hydrophobic acrylic, aspheric, and blue-blocking intraocular lenses. The use of the fourth generation fluoroquinolone antibiotic gatifloxacin has increased at the expense of older antibiotics.

Prevention of age-related macular degeneration

Age-related macular degeneration (AMD) is one of the leading causes of blindness in the developed world. Although effective treatment modalities such as anti-VEGF treatment have been developed for neovascular AMD, there is still no effective treatment for geographical atrophy, and therefore the most cost-effective management of AMD is to start with prevention. This review looks at current evidence on preventive measures targeted at AMD. Modalities reviewed include (1) nutritional supplements such as the Age-Related Eye Disease Study (AREDS) formula, lutein and zeaxanthin, omega-3 fatty acid, and berry extracts, (2) lifestyle modifications, including smoking and body-mass-index, and (3) filtering sunlight, i.e. sunglasses and blue-blocking intraocular lenses. In summary, the only proven effective preventive measures are stopping smoking and the AREDS formula.

Ultraviolet-B Phototoxicity and Hypothetical Photomelanomagenesis: Intraocular and Crystalline Lens Photoprotection

Ultraviolet-B (UV-B) radiation can cause phototoxic macular injuries in young people who have been sunbathing but not sungazing and in welders. Welders have a reportedly increased risk of uveal melanoma. We analyze phakic and pseudophakic risks for solar and welding arc UV-B exposure. Optical radiation measurement, analysis, and perspective. Spectral transmittances were measured for UV-transmitting, UV-blocking, and blue-blocking intraocular lenses (IOLs). The photoprotective performances of crystalline and intraocular lenses were analyzed using relevant epidemiologic and laboratory data and action spectra for acute retinal phototoxicity and melanoma photocarcinogenesis. Crystalline lens UV-B retinal protection is deficient in children and young adults, increasing their potential susceptibility to acute retinal phototoxicity and hypothetical photomelanomagenesis. UV-B radiation has sufficient energy/photon to induce primary melanomagenic DNA lesions, unlike blue light or UV-A radiation. UV-blocking and blue-blocking IOLs have negligible UV-B transmittance. UV-transmitting IOL transmittance of UV-B radiation is equivalent to that of a 15-year-old crystalline lens. If optical radiation exposure is responsible for welders' increased risk of uveal melanoma, then UV-B radiation is the most probable causative agent and spectacle wear is a potential confounding factor in epidemiologic studies of ocular melanoma. Welders under 30 years of age are at greater risk for welding maculopathy than older welders. Children, adults under 30 years of age, and pseudophakic individuals with UV-transmitting IOLs should wear sunglasses in bright environments because of the UV-B window in their crystalline lenses or IOLs.

Blue-blocking IOLs Decrease Photoreception Without Providing Significant Photoprotection

Violet and blue light are responsible for 45% of scotopic, 67% of melanopsin, 83% of human circadian (melatonin suppression) and 94% of S-cone photoreception in pseudophakic eyes (isoilluminance source). Yellow chromophores in blue-blocking intraocular lenses (IOLs) eliminate between 43 and 57% of violet and blue light between 400 and 500 nm, depending on their dioptric power. This restriction adversely affects pseudophakic photopic luminance contrast, photopic S-cone foveal threshold, mesopic contrast acuity, scotopic short-wavelength sensitivity and circadian photoreception. Yellow IOL chromophores provide no tangible clinical benefits in exchange for the photoreception losses they cause. They fail to decrease disability glare or improve contrast sensitivity. Most epidemiological evidence shows that environmental light exposure and cataract surgery are not significant risk factors for the progression of age-related macular degeneration (AMD). Thus, the use of blue-blocking IOLs is not evidence-based medicine. Most AMD occurs in phakic adults over 60 years of age, despite crystalline lens photoprotection far greater than that of blue-blocking IOLs. Therefore, if light does play some role in the pathogenesis of AMD, then 1) senescent crystalline lenses do not prevent it, so neither can blue-blocking IOLs that offer far less photoprotection, and 2) all pseudophakes should wear sunglasses in bright environments. Pseudophakes have the freedom to remove their sunglasses for optimal photoreception whenever they choose to do so, provided that they are not encumbered permanently by yellow IOL chromophores. In essence, yellow chromophores are placebos for prevention of AMD that permanently restrict a pseudophake's dim light and circadian photoreception at ages when they are needed most. If yellow IOLs had been the standard of care, then colorless UV-blocking IOLs could be advocated now as “premium” IOLs because they offer dim light and circadian photoreception roughly 15–20 years more youthful than blue-blocking 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 non-blue-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.

Film intraocular lens: a new way to choose the light-transmission spectrum

Currently, intraocular lenses (IOLs) are divided into two types in relation to ultraviolet radiation (UVR), UVR-only and UVR+blue-light-absorbing IOLs. It has been widely accepted that UV is harmful to eyes.1...

Fellow-eye comparison of posterior capsule opacification with AcrySof SN60AT and AF-1 YA-60BB blue-blocking intraocular lenses

To evaluate intraindividual differences in posterior capsule opacification (PCO) and visual performance of AcrySof SN60AT (Alcon Laboratories) and AF-1 YA-60BB (Hoya Corp.) intraocular lenses (IOLs). Ophthalmology Department, St. Thomas' Hospital, London, United Kingdom. In this prospective single-surgeon standardized-surgical-procedure fellow-eye comparison, an AcrySof SN60AT or an AF-1 YA-60BB IOL was randomized to the first eye of 36 patients and fellow-eye surgery was performed within 4 to 6 weeks. Follow-up was at 1, 3, 6, 12, and 24 months. Best distance- corrected logMAR visual acuity was measured at 100% and 9% contrast. Contrast sensitivity was measured using the Functional Acuity Contrast Test (FACT) on the Optec 3500 instrument (Stereo Optical Company, Inc.). Color vision was assessed with the Farnsworth Munsell 100-hue test. After pupil dilation, digital retroillumination photographs were taken and the percentage area of PCO was calculated using POCO software. Posterior capsule opacification was significantly greater in the AF-1 YA-60BB group than in the AcrySof SN60AT group at all time points (P<.0001), with the difference greatest at 24 months. At 24 months, 100% contrast visual acuity was significantly better in the AcrySof SN60AT group than in the AF-1 YA-60BB group (P = .0313); 9% contrast visual acuity was significantly better in the AcrySof SN60AT group from 6 months onward. There was no significant difference between groups in color vision or contrast sensitivity. Electron microscopy showed the AcrySof SN60AT IOL has a much sharper posterior edge profile. The AcrySof SN60AT IOL had better PCO performance and thus visual performance than the AF-1 YA-60BB IOL. This is attributable to the differences in optic edge design.

Transmittance characteristics of ultraviolet and blue-light-filtering intraocular lenses

To record the spectral transmittance curves of various ultraviolet (UV) and blue-light-filtering intraocular lenses (IOLs), evaluate their UV and blue-light-radiation- absorption capacities, and compare them with those of the natural crystalline lens. Department of Ophthalmology, Duisburg-Essen University, Essen, Germany. Eight IOLs from 6 manufacturers were evaluated. The transmittance of wavelengths from 200 nm to 800 nm was measured using a high-performance spectrophotometer with a diffuse transmittance accessory through a 1.5 mm aperture. All assessed IOLs provided good UVC (200 to 280 nm) and UVB (280 to 320 nm) protection, but 2 IOLs lacked sufficient UVA (320 to 400 nm) protection. Major differences in the absorption capacities were observed in the blue-light range (400 to 500 nm). The absorption characteristics of some UV and blue-light-filtering IOLs resembled those of the crystalline lens, but some differed. Long-term clinical trials should be performed to determine how blue-blocking IOLs affect the risk for progression of age-related macular degeneration.

The effect of chromatic dispersion on pseudophakic optical performance

Aim:Monochromatic and chromatic aberrations limit the visual performance of pseudophakic eyes. Chromatic aberration is caused by the chromatic dispersion of optical materials which can be characterised by their Abbe numbers....