The Effect of Blue-Light Filtering Intraocular Lenses on the Development and Progression of Neovascular Age-Related Macular Degeneration

Blue Light Filtration in Intraocular Lenses: Effects on Visual Function and Systemic Health

Blue light-filtering (BLF) intraocular lenses (IOLs) are designed to mimic the healthy natural adult crystalline lens. Studies that evaluated the relative merit of ultraviolet-only IOL design (ie, blocking wavelengths <400 nm) versus BLF IOL design (ie, filtering wavelengths ~400-475 nm in addition to blocking wavelengths <400 nm) on protection and function of the visual system suggest that neither design had a deleterious impact on visual acuity or contrast sensitivity. A BLF design may reduce some aspects of glare, such as veiling and photostress. BLF has been shown in many contexts to improve visual performance under conditions that are stressed by blue light, such as distance vision impaired by short-wave dominant haze. Furthermore, some data (mostly inferential) support the notion that BLF IOLs reduce actinic stress. Biomimetic BLF IOLs represent a conservative approach to IOL design that provides no harm for visual acuity, contrast sensitivity, or color vision while improving vision under certain circumstances (eg, glare).

The Effect of Blue-light Filtering Intraocular Lenses on the Development and Progression of Macular Atrophy in Eyes With Neovascular Age-related Macular Degeneration

PURPOSE

To assess the effect of blue-light filtering (BLF) intraocular lenses (IOLs) on the development and progression of macular atrophy (MA) in eyes with neovascular age-related macular degeneration (nAMD).

DESIGN

Retrospective, clinical cohort study.

METHODS

The study included patients with nAMD with anti-vascular endothelial growth factor (VEGF) injections who underwent uneventful cataract surgery between 2007 and 2018 with follow-up until June 2023. Subsequent MA rates were compared between subjects who received a BLF IOL or a non-BLF IOL. All optical coherence tomography scans were manually reviewed in a masked manner regarding patient baseline variables and IOL status by an experienced research technician. By using Heidelberg software, the area of MA was manually evaluated and calculated (mm2) by the program. The overall risk of developing new-onset MA and the effect of IOL type on disease progression were assessed. Death was included as a censoring event.

RESULTS

Included were 373 eyes of 373 patients (mean age, 78.6 ± 6.7 years at surgery; 67.4% were female). BLF IOLs were implanted in 206 eyes, and non-BLF IOLs were implanted in 167 eyes with comparable follow-up times (3164 ± 1420 days vs 3180 ± 1403 days, respectively, P = .908) and other baseline parameters (age, gender, corrected distance visual acuity, macular thickness, cumulative number of anti-VEGF injections). Nine preexisting and 77 new-onset MA cases were detected, with similar distribution between BLF and non-BLF eyes (P = .598 and P = .399, respectively). Both univariate Kaplan-Meier (P = .366) and multivariate Cox regression analyses adjusted for age and gender showed that BLF-IOLs were comparable to non-BLF IOLs regarding hazard for new-onset MA (hazard ratio [HR], 1.236; 95% CI, 0.784-1.949; P = .363). Final MA area at the last visit was 5.14 ± 4.71 mm2 for BLF IOLs and 8.56 ± 9.17 mm2 for non-BLF IOLs (P = .028), with the mean annual MA area increase of 0.78 ± 0.84 mm2 and 1.26 ± 1.32 mm2, respectively (P = .042).

CONCLUSIONS

BLF IOLs did not show added benefit over non-BLF IOLs in terms of MA-free survival but were associated with less progression over time in a cohort of patients with nAMD.

[Blue light and intraocular lenses (IOLs): Beliefs and realities]

The first intraocular lenses (IOLs) used for cataract surgery transmitted both ultraviolet (UV) radiation and visible light to the retina. Colorless UV-blocking IOLs were introduced and rapidly adopted in the 1980s. Yellow-tinted blue-blocking (also known as blue-filtering) IOLs were marketed in the early 1990s. Blue-blocking IOLs were intended to simulate age-related crystalline lens yellowing to reduce the cyanopsia that some patients experienced after cataract surgery. When blue-filtering IOLs were introduced in North America, however, blue-blocking chromophores were advocated as a way to protect patients from age-related macular degeneration (AMD) despite the lack of evidence that normal environmental light exposure causes AMD. The "blue light hazard" is a term that describes the experimental finding that acute, abnormally intense light exposures are potentially more phototoxic to the retina when short rather than long wavelengths are used. Thus, in brief exposures to intense light sources such as welding arcs, ultraviolet radiation is more hazardous than blue light, which is more hazardous than longer wavelength green or red light. International commissions have cautioned that the blue light hazard does not apply to normal indoor or outdoor light exposures. Nonetheless, the hazard is used for commercial purposes to suggest misleadingly that ambient environmental light can cause acute retinal phototoxicity and increase the risk of AMD. Very large epidemiological studies show that blue-blocking IOLs do not reduce the risk or progression of AMD. Additionally, blue-filtering IOLs or spectacles cannot decrease glare disability, because they decrease image and glare illuminance in the same proportion. Blue light is essential for older adults' scotopic photoreception needed to reduce the risk of nighttime falling and related injuries. It is also critical for circadian photoreception that is essential for good health, sleep and cognitive performance. Unfortunately, age-related pupillary miosis, retinal rod and ganglion cell photoreceptor degeneration and decreased outdoor activity all reduce the amount of healthful blue light available to older adults. Blue-restricting IOLs further reduce the available blue light at a time when older adults need it most. Patients and ophthalmologists are exposed to hypothesis-based advertisements for blue-filtering optical devices that suppress short wavelength light critical for vision in dim lighting and for good physical and mental health. Spectacle and intraocular lens selections should be based on scientific fact, not conjecture. Ideal IOLs should improve photoreception rather than limit it permanently. Practice efficiency, surgical convenience and physician-manufacturer relationships may eliminate a patient's opportunity to choose between colorless blue-transmitting IOLs and yellow-tinted, blue-restricting IOLs. Cataract surgeons ultimately determine whether their patients have the opportunity to make an informed choice about their future photoreception.

Lipofuscin, Its Origin, Properties, and Contribution to Retinal Fluorescence as a Potential Biomarker of Oxidative Damage to the Retina

Lipofuscin accumulates with age as intracellular fluorescent granules originating from incomplete lysosomal digestion of phagocytosed and autophagocytosed material. The purpose of this review is to provide an update on the current understanding of the role of oxidative stress and/or lysosomal dysfunction in lipofuscin accumulation and its consequences, particularly for retinal pigment epithelium (RPE). Next, the fluorescence of lipofuscin, spectral changes induced by oxidation, and its contribution to retinal fluorescence are discussed. This is followed by reviewing recent developments in fluorescence imaging of the retina and the current evidence on the prognostic value of retinal fluorescence for the progression of age-related macular degeneration (AMD), the major blinding disease affecting elderly people in developed countries. The evidence of lipofuscin oxidation in vivo and the evidence of increased oxidative damage in AMD retina ex vivo lead to the conclusion that imaging of spectral characteristics of lipofuscin fluorescence may serve as a useful biomarker of oxidative damage, which can be helpful in assessing the efficacy of potential antioxidant therapies in retinal degenerations associated with accumulation of lipofuscin and increased oxidative stress. Finally, amendments to currently used fluorescence imaging instruments are suggested to be more sensitive and specific for imaging spectral characteristics of lipofuscin fluorescence.

The Effect of Blue-Light Filtering Intraocular Lenses on the Development and Progression of Glaucoma

PRCIS

Among patients who underwent uneventful cataract surgery, an advantage was seen to blue-light filtering (BLF) intraocular lenses (IOLs) in terms of glaucoma-free survival and glaucoma procedure-free survival. Among patients with preexisting glaucoma, no advantage was seen.

PURPOSE

To assess the effect of BLF IOLs on the development and progression of glaucoma after cataract surgery.

PATIENTS AND METHODS

A retrospective cohort study of patients who underwent uneventful cataract surgery between 2007 and 2018 at Kymenlaakso Central Hospital, Finland. Survival analyses for the overall risk of developing glaucoma or undergoing glaucoma procedures were assessed between patients who received a BLF IOL (SN60WF) and a non-BLF IOL (ZA9003 and ZCB00). A separate analysis was performed on patients with preexisting glaucoma.

RESULTS

Included 11,028 eyes of 11,028 patients with a mean age of 75 ± 9 years (62% females). The BLF IOL was used in 5188 eyes (47%) and the non-BLF IOL in 5840 eyes (53%). During the follow-up (mean: 55 ± 34 mo), 316 cases of glaucoma were diagnosed. Glaucoma-free survival rates showed an advantage to the BLF IOL ( P = 0.036). In a Cox regression analysis controlling for age and sex the use of a BLF IOL was again associated with a lower ratio of glaucoma development (hazard ratio:0.778; 95% CI: 0.621-0.975). Furthermore, glaucoma procedure-free survival analysis revealed an advantage to the BLF IOL (hazard ratio:0.616; 95% CI: 0.406-0.935). Among 662 cases, which already had glaucoma at the time of surgery, no significant differences were seen in any outcome.

CONCLUSIONS

Among a large cohort of patients who underwent cataract surgery, the use of BLF IOLs was associated with favorable glaucoma outcomes compared with the use of non-BLF IOLs. Among patients with preexisting glaucoma, no significant advantage was seen.

Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review

INTRODUCTION

Exposure to blue light has seriously increased in our environment since the arrival of light emitting diodes (LEDs) and, in recent years, the proliferation of digital devices rich in blue light. This raises some questions about its potential deleterious effects on eye health. The aim of this narrative review is to provide an update on the ocular effects of blue light and to discuss the efficiency of methods of protection and prevention against potential blue light-induced ocular injury.

METHODS

The search of relevant English articles was conducted in PubMed, Medline, and Google Scholar databases until December 2022.

RESULTS

Blue light exposure provokes photochemical reactions in most eye tissues, in particular the cornea, the lens, and the retina. In vitro and in vivo studies have shown that certain exposures to blue light (depending on the wavelength or intensity) can cause temporary or permanent damage to some structures of the eye, especially the retina. However, currently, there is no evidence that screen use and LEDs in normal use are deleterious to the human retina. Regarding protection, there is currently no evidence of a beneficial effect of blue blocking lenses for the prevention of eye diseases, in particular age-related macular degeneration (AMD). In humans, macular pigments (composed of lutein and zeaxanthin) represent a natural protection by filtering blue light, and can be increased through increased intake from foods or food supplements. These nutrients are associated with lower risk for AMD and cataract. Antioxidants such as vitamins C, E, or zinc might also contribute to the prevention of photochemical ocular damage by preventing oxidative stress.

CONCLUSION

Currently, there is no evidence that LEDs in normal use at domestic intensity levels or in screen devices are retinotoxic to the human eye. However, the potential toxicity of long-term cumulative exposure and the dose-response effect are currently unknown.

m6A Modification-Association with Oxidative Stress and Implications on Eye Diseases

Oxidative stress (OS) refers to a state of imbalance between oxidation and antioxidation. OS is considered to be an important factor leading to aging and a range of diseases. The eyes are highly oxygen-consuming organs. Due to its continuous exposure to ultraviolet light, the eye is particularly vulnerable to the impact of OS, leading to eye diseases such as corneal disease, cataracts, glaucoma, etc. The N6-methyladenosine (m6A) modification is the most investigated RNA post-transcriptional modification and participates in a variety of cellular biological processes. In this study, we review the role of m6A modification in oxidative stress-induced eye diseases and some therapeutic methods to provide a relatively overall understanding of m6A modification in oxidative stress-related eye diseases.

The Blue Light Hazard Versus Blue Light Hype

PURPOSE

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.

DESIGN

Perspective.

METHODS

Analysis and integration of data regarding the blue light hazard and blue-blocking filters in ophthalmology and related disciplines.

RESULTS

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.

CONCLUSIONS

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.

The Long-Term Effect of Blue-Light Blocking Spectacle Lenses on Adults’ Contrast Perception

Purpose

To evaluate the long-term effect of two different degrees of blue-light blocking (BB) spectacle lenses on adults’ contrast perception under various lighting conditions.

Methods

In total, 144 healthy adults aged 24.70 (±4.32 years) were recruited to this randomized controlled trial. The participants were randomly divided into three groups and used three different spectacle lenses (15% BB: 15% blue-blocking spectacle lenses; 30% BB: 30% blue-blocking spectacle lenses; RC: regular clear lenses serving as control). Contrast sensitivity under four light conditions (scotopic and photopic, both with/without glare) was measured using standard clinical tests at baseline, 1 month, 3 months and 6 months of use. The area under the log contrast sensitivity function (AULCSF) was also computed as an index for their overall contrast sensitivity across spatial frequencies.

Results

There was no significant difference in AULCSFs among the three types of spectacle lenses under any light condition (all P > 0.81). No statistical difference was found in the AULSCF among the four time points (all P > 0.39), with no interaction between the effects of group and time (all P > 0.42).

Conclusion

Wearing blue-light blocking lens had no clinically significant effect on adults’ long-term contrast perception under scotopic or photopic conditions, or with glare.

Effect of cataract surgery on wet age-related macular degeneration activity

BACKGROUND

Wet age-related macular degeneration (AMD) and age-related cataract are often coexisting causes of visual impairment. Yet, the timing of cataract surgery in wet AMD patients is controversial.

METHODS

One hundred and eleven eyes of 111 patients with wet AMD underwent cataract surgery at Helsinki University Hospital in Finland during 2014-2018. Best-corrected visual acuity and central subfield macular thickness (CSMT) were analysed at the time of wet AMD diagnosis, at the last recording prior to cataract surgery and at the first recording and at 1 year after surgery. The cumulative number of antivascular endothelial growth factor (anti-VEGF) injections at surgery, systemic and topical medication and postoperative anti-VEGF burden were recorded.

RESULTS

Mean age was 78.9 ± 5.6 years at the time of surgery. Central subfield macular thickness (CSMT) significantly decreased (280.1 ± 75.0 µm preoperatively to 268.6 ± 67.6 µm at the first postoperative recording, p = 0.001, and to 265.9 ± 67.9 µm at 1 year, p = 0.003), visual acuity improved (0.70 ± 0.46 logMAR units preoperatively to 0.39 ± 0.40 at the first postoperative recording, and to 0.33 ± 0.34 at 1 year, p < 0.001 for both) and anti-VEGF treatment intervals lengthened despite the surgery (6.53 ± 2.08 weeks prior to surgery to 7.03 ± 2.23 weeks at 1 year, p = 0.246, and to 7.05 ± 2.57 weeks at the last documented visit, p = 0.035). A CSMT increase of over 30% from the preoperative values was seen in only one case (1 out of 111 eyes, 0.9%). Macular status at surgery, wet AMD subtype, comorbidity of type II diabetes, systemic drugs and topical anti-inflammatory medication were not associated with macular changes nor with treatment intervals after surgery. The cumulative number of anti-VEGF injections correlated neither with CSMT change postoperatively (r = -0.051, p = 0.619) nor with CSMT change at 1 year (r = 0.091, p = 0.426).

CONCLUSION

Satisfactory visual outcomes and controlled disease activity were seen in patients with wet AMD undergoing cataract surgery. We found no evidence to support delaying surgery in patients who require it.

Effect of Blue Light-Filtering Intraocular Lenses on Age-Related Macular Degeneration: A Nationwide Cohort Study With 10-Year Follow-up

PURPOSE

To determine the incidence rate of age-related macular degeneration (AMD) after cataract surgery and compare the relative incidence of AMD in pseudophakes with blue light-filtering intraocular lenses (BF-IOLs) and non-BF-IOLs.

DESIGN

A nationwide cohort study conducted using the Taiwan National Health Insurance Research Database.

METHODS

We enrolled 186,591 patients who underwent cataract surgery in both eyes between 2008 and 2013 and monitored them from the index date (the date of first cataract surgery) until AMD, death, loss to follow-up, or December 31, 2017, whichever occurred first. Propensity score matching (PSM) was used to balance the baseline characteristics between the BF-IOL and non-BF-IOL groups.

RESULTS

BF-IOLs were implanted in 21,126 patients (11.3%) and non-BF-IOLs were implanted in 165,465 patients (88.7%). Patients in the BF-IOL group tended to be younger, with fewer men, different cataract surgery years, higher income, more nonmanual workers, more patients from urban and suburban areas, and fewer chronic diseases compared with the non-BF-IOL group. With a mean follow-up period of 6.1 years (range, 1-10 years) after cataract surgery, 12,533 and 1655 patients developed non-exudative AMD and exudative AMD, respectively. The incidence rate of non-exudative AMD and exudative AMD (per 1000 person-years) was 9.95 and 1.22 for the BF-IOL group and 11.13 and 1.44 for the non-BF-IOL group, respectively. After PSM, no statistical difference in the incidence rate of nonexudative AMD (hazards ratio, 0.95; 95% CI, 0.88-1.03) and exudative AMD (hazard ratio, 0.96; 95% CI, 0.77-1.18) was observed between the BF-IOL and non-BF-IOL groups.

CONCLUSIONS

In Taiwan, the incidence rate of AMD after cataract surgery was 11.59 per 1000 person-years. The use of a BF-IOL for up to 10 years had no apparent advantage over a non-BF-IOL in the incidence of AMD.

Prevention of the Onset of Age-Related Macular Degeneration

Age-related macular degeneration (AMD) represents the leading cause of irreversible blindness in elderly people, mostly after the age of 65. The progressive deterioration of visual function in patients affected by AMD has a significant impact on quality of life and has also high social costs. The current therapeutic options are only partially able to slow down the natural course of the disease, without being capable of stopping its progression. Therefore, better understanding of the possibilities to prevent the onset of the disease is needed. In this regard, a central role is played by the identification of risk factors, which might participate to the development of the disease. Among these, the most researched are dietary risk factors, lifestyle, and light exposure. Many studies showed that a higher dietary intake of nutrients, such as lutein, zeaxanthin, beta carotene, omega-3 fatty acids and zinc, reduced the risk of early AMD. Regarding lifestyle habits, the association between smoking and AMD is currently accepted. Finally, retinal damage caused by ultraviolet rays and blue light is also worthy of attention. The scope of this review is to summarize the present knowledge focusing on the measures to adopt in order to prevent the onset of AMD.

The Influence of Blue-Filtering Intraocular Lenses Implant on Exudative Age-Related Macular Degeneration: A Case-Control Study

Purpose

To determine whether the use of a blue light-filtering intraocular lens (IOL) prevents the onset of wet age-related macular degeneration (AMD). More precisely, we examined the proportion of blue light-filtering IOL in a wet AMD patients’ sample and compared it with a general North American pseudophakic population sample.

Design

Retrospective case–control study.

Methods

Case patients were diagnosed and treated for wet AMD and had prior IOL implantation at least 3 years before the diagnosis of wet AMD. Control patients were randomly selected among patients who had cataract surgery at our institution. They were exempt of AMD and paired for the year of surgery, sex and age at cataract surgery. A total of 196 patients were included in each study group.

Results

Among patients with wet AMD, 62.8% had a blue light-filtering IOL compared with 63.3% among control patients (p = 0.92). Mean time between implantation and injection of anti-VEGF in AMD patients was 6.62 years (95% confidence interval (CI): 6.04–7.19) in non-blue light-filtering IOL group and 5.76 years (95% CI: 5.41–6.11) in blue light-filtering IOL group (p = 0.0120).

Conclusion

No correlations could be established between the presence of a blue light filter in the IOL and the occurrence of wet AMD. AMD patients without blue light-filtering IOL were injected significantly later than patients with an IOL filtering blue light, which contradict the potential clinical benefit of the blue light filter.