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

Potential guidelines for cataract surgery and rehabilitation in visually impaired patients: Literature analysis

Cataracts can reduce the quality of vision in visually impaired patients who already have a visual impairment. The most common causes of low vision include age-related macular degeneration (AMD), high myopia (HM), diabetic retinopathy (DR), glaucoma (GL), and inherited degenerative ocular diseases. The surgery aims to improve their independence, quality of life, and ability to engage in daily, social, and work activities. Phacoemulsification and intraocular lens (IOL) implantation, combined with visual rehabilitation, can improve visual acuity of visually impaired patients. Therefore, comprehensive guidelines for cataract surgery in patients with low vision would be beneficial to ensure optimal surgical outcomes by improving surgical planning, execution, and postoperative care, along with a well-coordinated rehabilitation process. In cases of reduced metabolism, such as low vision, oxidative stress can be aggravated by light exposure and surgical interventions. Thus, maintaining redox balance is crucial for stabilizing retinal conditions. Patients with visual impairments rely on retinal regions with the greatest residual function, and cataract surgery aims to enhance focus on these areas, improving reading quality and reducing scotoma perception. Thorough informed consent is crucial, ensuring that patients are fully aware of the potential risks, benefits, and limitations of surgery. Close postoperative follow-up in the first 6 months is crucial to detect and manage any complications promptly, such as reactivation of maculopathy. The aim of this work is to establish potential guidelines for optimal rehabilitation outcomes through careful literature analysis.

Effects of artificial light with different spectral compositions on refractive development and matrix metalloproteinase 2 and tissue inhibitor of metalloproteinases 2 expression in the sclerae of juvenile guinea pigs

Artificial light can affect eyeball development and increase myopia rate. Matrix metalloproteinase 2 (MMP-2) degrades the extracellular matrix, and induces its remodeling, while tissue inhibitor of matrix MMP-2 (TIMP-2) inhibits active MMP-2. The present study aimed to look into how refractive development and the expression of MMP-2 and TIMP-2 in the guinea pigs' remodeled sclerae are affected by artificial light with varying spectral compositions. Three weeks old guinea pigs were randomly assigned to groups exposed to five different types of light: natural light, LED light with a low color temperature, three full spectrum artificial lights, i.e. E light (continuous spectrum in the range of ~390-780 nm), G light (a blue peak at 450 nm and a small valley 480 nm) and F light (continuous spectrum and wavelength of 400 nm below filtered). A-scan ultrasonography was used to measure the axial lengths of their eyes, every two weeks throughout the experiment. Following twelve weeks of exposure to light, the sclerae were observed by optical and transmission electron microscopy. Immunohistochemistry, Western blot and RT-qPCR were used to detect the MMP-2 and TIMP-2 protein and mRNA expression levels in the sclerae. After four, six, eight, ten, and twelve weeks of illumination, the guinea pigs in the LED and G light groups had axial lengths that were considerably longer than the animals in the natural light group while the guinea pigs in the E and F light groups had considerably shorter axial lengths than those in the LED group. Following twelve weeks of exposure to light, the expression of the scleral MMP-2 protein and mRNA were, from low to high, N group, E group, F group, G group, LED group; however, the expression of the scleral TIMP-2 protein and mRNA were, from high to low, N group, E group, F group, G group, LED group. The comparison between groups was statistically significant (p<0.01). Continuous, peaks-free or valleys-free artificial light with full-spectrum preserves remodeling of scleral extracellular matrix in guinea pigs by downregulating MMP-2 and upregulating TIMP-2, controlling eye axis elongation, and inhibiting the onset and progression of myopia.

Blue-Light Filtering Monofocal Intraocular Lenses: A Study on Optical Function and Tolerance to Misalignment

PURPOSE

To investigate the optical performance and tolerance to misalignment of blue-light filtering monofocal intraocular lenses (IOLs).

METHODS

The optical properties of two monofocal IOLs featuring yellow chromophores, CT Lucia 621 PY (Carl Zeiss Meditec AG) and Clareon CNA0T0 (Alcon Laboratories, Inc), were assessed in monochromatic and polychromatic light while introducing spherical aberration (SA). Optical quality metrics derived from the modulation transfer function were assessed after optimal IOL centration at 3- and 4.5-mm pupils. In addition, each IOL's tolerance to misalignment was examined by inducing up to 1 mm of decentration and the effect of tilting it by 5 degrees at 3 mm.

RESULTS

The IOLs' resolution and contrast, while tested using a 3-mm aperture and an SA-neutral corneal model, indicated the CT Lucia 621 PY had a slightly higher modulation transfer function (MTF) at 50 lp/mm than the CNA0T0 under monochromatic conditions (0.77 vs 0.69). On introducing SA with (0.49 vs 0.40) and without (0.75 vs. 0.70) chromatic aberration, the CT Lucia 621 PY maintained its minimally better performance. When assessed with a 4.5-mm aperture in monochromatic light, the CT Lucia 621 PY displayed improved MTF with aberration-free cornea (0.71 vs 0.40) but performed worse after introducing SA (0.44 vs 0.62). However, both lenses achieved comparable MTF values under spherical and chromatic aberrations (0.28 vs 0.27). The IOL misalignment test revealed a better tolerance to tilt and decentration of the CT Lucia 621 PY across all conditions.

CONCLUSIONS

The CT Lucia 621 PY and CNA0T0 showed similar optical quality in different situations, with equal simulated distance visual acuity for both models. However, the CT Lucia 621 PY's aspheric design offers an advantage when dealing with often imperfect physiological conditions, displaying a more robust performance under tilt and decentration. [J Refract Surg. 2024;40(2):e79-e88.].

Nighttime Outdoor Artificial Light and Risk of Age-Related Macular Degeneration

Importance

Light pollution's impact on human health is increasingly recognized, but its link to exudative age-related macular degeneration (EAMD) remains unclear.

Objective

To investigate the association between exposure to outdoor artificial light at night (OALAN) and the risk of incident EAMD.

Design, Setting, and Participants

In this nationwide population-based case-control study, all individuals 50 years or older with newly diagnosed EAMD between January 1, 2010, and December 31, 2011, were identified with reference to the Korean National Health Insurance Service registration program database for rare and intractable diseases. Birth year- and sex-matched controls (with no EAMD diagnosis until 2020) were selected at a 1:30 ratio. Data were acquired from May 1 to December 31, 2021, and analyzed from June 1 to November 30, 2022.

Exposures

Mean levels of OALAN at participants' residential addresses during 2008 and 2009 were estimated using time-varying satellite data for a composite view of persistent nighttime illumination at an approximate scale of 1 km2.

Main Outcomes and Measures

The hazard ratios (HRs) and 95% CIs of the association between residential OALAN and risk of incident EAMD were determined based on maximum likelihood estimation after adjusting for sociodemographic characteristics, comorbidities, and area-level risk factors (ie, nighttime traffic noise and particulate matter of aerodynamic diameter ≤10 μm in each participant's administrative district of residence).

Results

A total of 126 418 participants were included in the analysis (mean [SD] age, 66.0 [7.9] years; 78 244 men [61.9%]). Of these, 4078 were patients with newly diagnosed EAMD and 122 340 were EAMD-free matched controls. In fully adjusted models, an IQR (55.8 nW/cm2/sr) increase in OALAN level was associated with an HR of 1.67 (95% CI, 1.56-1.78) for incident EAMD. The exposure-response curve demonstrated a nonlinear, concave upward slope becoming more pronounced at higher levels of light exposure (ie, at approximately 110 nW/cm2/sr). In a subgroup analysis, an IQR increase in OALAN was associated with increased risk of incident EAMD in urban areas (HR, 1.46 [95% CI, 1.33-1.61]) but not in rural areas (HR, 1.01 [95% CI, 0.84-1.22]).

Conclusions and Relevance

In this nationwide population-based case-control study, higher levels of residential OALAN were associated with an increased risk of incident EAMD. Future studies with more detailed information on exposure, individual adaptive behaviors, and potential mediators are warranted.

Evaluation of visual performance and eye movements in patients with blue light-filtering intraocular lenses versus ultraviolet light-filtering intraocular lenses

Background

Eye movement plays an important role in visual perception and provides essential visual information for everyday tasks. Our previous study indicated that the visual performance and eye movement pattern were impaired in age-related cataract patients and could be improved after cataract surgery, but the impact of different intraocular lens (IOL) types was obscure. Previous studies found that blue light might affect the eye movement pattern and cognitive function. In this study, we explored the visual performance and eye movement pattern in post-cataract surgery patients implanted with blue light-filtering IOLs or ultraviolet (UV) light-filtering IOLs to further understand the impact of different types of IOLs on and daily visual performance and eye movement pattern and to help ophthalmologists and patients make the personalized option of IOL types in future.

Methods

Patients after both-eye cataract surgeries were included in this study. Eye movement behaviors were automatically recorded by an eye tracker while performing three performance-based everyday tasks (non-social object search, face recognition, and reading). Visual performance and eye movement parameters were compared between participants with blue light-filtering IOLs and UV light-filtering IOLs. The correlation between visual performance and eye movement parameters was explored to determine which eye movement parameters had a significant influence on visual performance outcomes.

Results

A total of 30 patients (16 with blue light-filtering IOLs and 14 with UV light-filtering IOLs) were included. In this study, we found that the eye movement pattern was slightly different with these two IOLs: during non-social object visual search task, time to first fixation and fixation counts before first fixation were notably increased in yellow-tinted blue light-filtering IOL patients. During reading task, a higher total fixation count was also found in blue light-filtering IOL patients. However, the visual performance of these two IOLs was close, except for a quicker search of the target object with clear UV light-filtering IOLs.

Conclusion

Both blue light-filtering and UV light-filtering IOLs were able to successfully restore visual function and yield satisfactory outcomes after cataract surgery. Although subtle, yellow-tinted IOLs did have a slight but significant impact on visual performance and the eye movement pattern of elderly patients when handling everyday tasks.

Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults

BACKGROUND

'Blue-light filtering', or 'blue-light blocking', spectacle lenses filter ultraviolet radiation and varying portions of short-wavelength visible light from reaching the eye. Various blue-light filtering lenses are commercially available. Some claims exist that they can improve visual performance with digital device use, provide retinal protection, and promote sleep quality. We investigated clinical trial evidence for these suggested effects, and considered any potential adverse effects.

OBJECTIVES

To assess the effects of blue-light filtering lenses compared with non-blue-light filtering lenses, for improving visual performance, providing macular protection, and improving sleep quality in adults.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL; containing the Cochrane Eyes and Vision Trials Register; 2022, Issue 3); Ovid MEDLINE; Ovid Embase; LILACS; the ISRCTN registry; ClinicalTrials.gov and WHO ICTRP, with no date or language restrictions. We last searched the electronic databases on 22 March 2022.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), involving adult participants, where blue-light filtering spectacle lenses were compared with non-blue-light filtering spectacle lenses.

DATA COLLECTION AND ANALYSIS

Primary outcomes were the change in visual fatigue score and critical flicker-fusion frequency (CFF), as continuous outcomes, between baseline and one month of follow-up. Secondary outcomes included best-corrected visual acuity (BCVA), contrast sensitivity, discomfort glare, proportion of eyes with a pathological macular finding, colour discrimination, proportion of participants with reduced daytime alertness, serum melatonin levels, subjective sleep quality, and patient satisfaction with their visual performance. We evaluated findings related to ocular and systemic adverse effects. We followed standard Cochrane methods for data extraction and assessed risk of bias using the Cochrane Risk of Bias 1 (RoB 1) tool. We used GRADE to assess the certainty of the evidence for each outcome.

MAIN RESULTS

We included 17 RCTs, with sample sizes ranging from five to 156 participants, and intervention follow-up periods from less than one day to five weeks. About half of included trials used a parallel-arm design; the rest adopted a cross-over design. A variety of participant characteristics was represented across the studies, ranging from healthy adults to individuals with mental health and sleep disorders. None of the studies had a low risk of bias in all seven Cochrane RoB 1 domains. We judged 65% of studies to have a high risk of bias due to outcome assessors not being masked (detection bias) and 59% to be at high risk of bias of performance bias as participants and personnel were not masked. Thirty-five per cent of studies were pre-registered on a trial registry. We did not perform meta-analyses for any of the outcome measures, due to lack of available quantitative data, heterogenous study populations, and differences in intervention follow-up periods. There may be no difference in subjective visual fatigue scores with blue-light filtering lenses compared to non-blue-light filtering lenses, at less than one week of follow-up (low-certainty evidence). One RCT reported no difference between intervention arms (mean difference (MD) 9.76 units (indicating worse symptoms), 95% confidence interval (CI) -33.95 to 53.47; 120 participants). Further, two studies (46 participants, combined) that measured visual fatigue scores reported no significant difference between intervention arms. There may be little to no difference in CFF with blue-light filtering lenses compared to non-blue-light filtering lenses, measured at less than one day of follow-up (low-certainty evidence). One study reported no significant difference between intervention arms (MD - 1.13 Hz lower (indicating poorer performance), 95% CI - 3.00 to 0.74; 120 participants). Another study reported a less negative change in CFF (indicating less visual fatigue) with high- compared to low-blue-light filtering and no blue-light filtering lenses. Compared to non-blue-light filtering lenses, there is probably little or no effect with blue-light filtering lenses on visual performance (BCVA) (MD 0.00 logMAR units, 95% CI -0.02 to 0.02; 1 study, 156 participants; moderate-certainty evidence), and unknown effects on daytime alertness (2 RCTs, 42 participants; very low-certainty evidence); uncertainty in these effects was due to lack of available data and the small number of studies reporting these outcomes. We do not know if blue-light filtering spectacle lenses are equivalent or superior to non-blue-light filtering spectacle lenses with respect to sleep quality (very low-certainty evidence). Inconsistent findings were evident across six RCTs (148 participants); three studies reported a significant improvement in sleep scores with blue-light filtering lenses compared to non-blue-light filtering lenses, and the other three studies reported no significant difference between intervention arms. We noted differences in the populations across studies and a lack of quantitative data. Device-related adverse effects were not consistently reported (9 RCTs, 333 participants; low-certainty evidence). Nine studies reported on adverse events related to study interventions; three studies described the occurrence of such events. Reported adverse events related to blue-light filtering lenses were infrequent, but included increased depressive symptoms, headache, discomfort wearing the glasses, and lower mood. Adverse events associated with non-blue-light filtering lenses were occasional hyperthymia, and discomfort wearing the spectacles. We were unable to determine whether blue-light filtering lenses affect contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels or overall patient visual satisfaction, compared to non-blue-light filtering lenses, as none of the studies evaluated these outcomes.

AUTHORS' CONCLUSIONS

This systematic review found that blue-light filtering spectacle lenses may not attenuate symptoms of eye strain with computer use, over a short-term follow-up period, compared to non-blue-light filtering lenses. Further, this review found no clinically meaningful difference in changes to CFF with blue-light filtering lenses compared to non-blue-light filtering lenses. Based on the current best available evidence, there is probably little or no effect of blue-light filtering lenses on BCVA compared with non-blue-light filtering lenses. Potential effects on sleep quality were also indeterminate, with included trials reporting mixed outcomes among heterogeneous study populations. There was no evidence from RCT publications relating to the outcomes of contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels, or overall patient visual satisfaction. Future high-quality randomised trials are required to define more clearly the effects of blue-light filtering lenses on visual performance, macular health and sleep, in adult populations.

Cataract Surgery-Indications, Techniques, and Intraocular Lens Selection

BACKGROUND

Opacification of the lens of the eye (cataract) is usually due to aging. It is a painless, progressive condition that affects contrast and color perception and alters refraction, leading to visual loss that may be total. In cataract surgery, the turbid lens is replaced by an artificial lens. An estimated 600 000 to 800 000 such procedures are performed in Germany each year.

METHODS

This review is based on pertinent publications retrieved by a selective search in PubMed, including meta-analyses, Cochrane reviews, and randomized controlled clinical trials (RCTs).

RESULTS

Cataract is the most common reversible cause of blindness around the world (approximately 95 million people). The surgical replacement of a turbid lens with an artificial lens is usually carried out under local anesthesia. The standard technique for fragmentation of the nucleus of the lens is ultrasonic phacoemulsification. RCTs have not shown the superiority of the femtosecond laser over phacoemulsification for this purpose so far. The spectrum of artificial intraocular lenses, aside from the conventional type with a single focus, include lenses with multiple foci, extended-depth-of-focus (EDOF) lenses, and astigmatism-correcting lenses.

CONCLUSION

In Germany, cataract surgery is usually performed on an outpatient basis under local anesthesia. Artificial lenses with various additional functions are available nowadays; the choice of lens depends on the needs of the individual patient. Patients must be adequately informed about the advantages and disadvantages of the different lens systems.

Content, Readability, and Accountability of Online Health Information for Patients Regarding Blue Light and Impact on Ocular Health

Objective To evaluate the quality and readability of online health content regarding the ocular health effects of blue light. Methods Five commercial and five non-commercial websites with content regarding the ocular effect of blue light were examined. Quality evaluations were conducted using a 14-question assessment composed by the authors and the 16-question DISCERN instrument. Website accountability was evaluated via the Journal of the American Medical Association (JAMA) benchmarks. Readability was determined using an online tool (Readable). Correlational and comparative analyses were conducted where appropriate. Results The average questionnaire score was 84 (standard deviation [SD] ± 17.89, 95% confidence interval [CI] 77.32-90.68) out of 136 points (61.8%). Significant differences in quality were identified between websites (p = 0.02), with Healthline achieving the highest score. Compared to commercial websites, non-commercial websites trended toward having significantly higher median questionnaire scores (p = 0.06). Zero websites achieved all four JAMA benchmarks. The average reading grade level of content was 10.43 (SD ± 1.15, 95% CI 9.60 - 11.25), with differences between websites trending toward significance (p = 0.09). There was no correlation between resource readability and quality (ρ = 0.28; p = 0.43) or accountability (ρ = 0.47; p = 0.17). Conclusions There remain substantial deficiencies in the quality, accountability, and readability of online content concerning the effect of blue light on ocular health. Clinicians and patients must recognize such issues when recommending and consuming these resources.

Clinical Evaluation of a Modified Light Transmission Short-Wavelength Filtering Intraocular Lens Compared to a Colorless Control

INTRODUCTION

The aim of this study was to evaluate the safety and efficacy of a violet-light filtering intraocular lens (IOL) compared to a colorless IOL control.

METHODS

This was a prospective, bilateral, randomized, comparative, patient/evaluator-masked multi-center clinical trial at 12 sites in the USA. Patients underwent standard small-incision phacoemulsification cataract extraction. Visual acuity, contrast sensitivity, and color vision were tested 12 months postoperatively. Patient satisfaction and vision-related quality of life were evaluated based on directed patient responses obtained from a binocular subjective questionnaire.

RESULTS

A total of 250 subjects were bilaterally implanted with the violet-light filtering TECNIS monofocal ZV9003 (n = 126) and colorless TECNIS monofocal ZA9003 (n = 124). Mean uncorrected distance visual acuity (UDVA) was 0.123 LogMAR for ZV9003 and 0.116 LogMAR for the ZA9003 group. Mean corrected distance visual acuity (CDVA) was 0.00 LogMAR for both groups. No significant difference was found between the groups for 22/25 questionnaire categories, including color perception. A significant difference was found in favor of the ZV9003 group for day driving, night driving, and frustration with vision. Contrast sensitivity mean difference was < 0.05 log units across all lighting conditions and spatial frequencies.

CONCLUSION

No difference was found between groups for visual acuity, contrast sensitivity, color testing, and adverse events as well as with the majority of optical/visual symptoms. A statistical difference was noted in driving and frustration with eyesight that may be related to benefits of using a violet-light filtering chromophore. Overall, the violet-light filtering ZV9003 showed excellent visual acuity and contrast sensitivity results with a low incidence of optical/visual symptoms.

Effects of artificial light with different spectral composition on eye axial growth in juvenile guinea pigs

The purpose of the study was to investigate the effect of artificial light with different spectral composition and distribution on axial growth in guinea pigs. Three-week-old guinea pigs were randomly assigned to groups exposed to natural light, low color temperature light-emitting diode (LED) light, two full spectrum artificial lights (E light and Julia light) and blue light filtered light with the same intensity. Axial lengths of guinea pigs' eyes were measured by A-scan ultrasonography prior to the experiment and every 2 weeks during the experiment. After light exposure for 12 weeks, retinal dopamine (DA), dihydroxy-phenylacetic acid (DOPAC) levels and DOPAC/DA ratio were analyzed by high-pressure liquid chromatography electrochemical detection and retinal histological structure was observed. Retinal melanopsin expression was detected using Western blot and immunohistochemistry. After exposed to different kinds of light with different spectrum for 4 weeks, the axial lengths of guinea pigs' eyes in LED group and Julia light group were significantly longer than those of natural light group. After 6 weeks, the axial lengths in LED light group were significantly longer than those of E light group and blue light filtered group. The difference between axial lengths in E light group and Julia light group showed statistical significance after 8 weeks (p<0.05). After 12 weeks of light exposure, the comparison of retinal DOPAC/DA ratio and melanopsin expression in each group was consistent with that of axial length. In guinea pigs, continuous full spectrum artificial light with no peak or valley can inhibit axial elongation via retinal dopaminergic and melanopsin system.

A review of the current state of research on artificial blue light safety as it applies to digital devices

Light is necessary for human health and well-being. As we spend more time indoors, we are being increasingly exposed to artificial light. The development of artificial lighting has allowed us to control the brightness, colour, and timing of our light exposure. Yet, the widespread use of artificial light has raised concerns about the impact of altering our light environment on our health. The widespread adoption of personal digital devices over the past decade has exposed us to yet another source of artificial light. We spend a significant amount of time using digital devices with light-emitting screens, including smartphones and tablets, at close range. The light emitted from these devices, while appearing white, has an emission spectrum with a peak in the blue range. Blue light is often characterised as hazardous as its photon energy is higher than that of other wavelengths of visible light. Under certain conditions, visible blue light can cause harm to the retina and other ocular structures. Blue light can also influence the circadian rhythm and processes mediated by melanopsin-expressing intrinsically photosensitive retinal ganglion cells. While the blue component of sunlight is necessary for various physiological processes, whether the low-illuminance artificial blue light emitted from digital devices presents a risk to our health remains an ongoing area of debate. As technological advancements continue, it is relevant to understand how new devices may influence our well-being. This review examines the existing research on artificial blue light safety and the eye, visual performance, and circadian functions.

Photopic and Mesopic Contrast Sensitivity Function in the Presence of Glare and the Effect of Filters in Young Healthy Adults

Purpose: The aim of this study was to evaluate the effect of four different filters on contrast sensitivity under photopic and mesopic conditions with and without glare.

Methods: A forced choice algorithm in a Bayesian psychophysical procedure was utilized to evaluate the spatial luminance contrast sensitivity. Five different spatial frequencies were evaluated: 1.5, 3, 6, 12, and 18 cycles per degree (cpd). The measurements were performed under 4 settings: photopic and mesopic luminance with glare and no glare. Two long pass filters (LED light reduction and 511nm filter) and two selective absorption filters (ML41 and emerald filter) and a no filter condition were evaluated. The measurements were performed in 9 young subjects with healthy eyes.

Results: For the no filter condition, there was no difference between glare and no glare settings for the photopic contrast sensitivity measurements whereas in the mesopic setting, glare reduced the contrast sensitivity significantly at all spatial frequencies. There was no statistically significant difference between contrast sensitivity measurements obtained with different filters under both photopic conditions and the mesopic glare condition. In the mesopic no glare condition, the contrast sensitivity at 6 cpd with 511, ML41 and emerald filters was significantly reduced compared to no filter condition (p = 0.045, 0.045, and 0.071, respectively). Similarly, with these filters the area under the contrast sensitivity function in the mesopic no glare condition was also reduced. A significant positive correlation was seen between the filter light transmission and the average AULCSF in the mesopic non-glare condition.

Conclusion: The contrast sensitivity measured with the filters was not significantly different than the no filter condition in photopic glare and no glare setting as well as in mesopic glare setting. In mesopic setting with no glare, filters reduced contrast sensitivity.

Safety and effectiveness of an iris hook assisted phacoemulsification in vitrectomized eyes

AIM

To introduce a simple iris hook assisted phacoemulsification (PE) procedure and evaluate the safety and efficacy of it in completely vitrectomized eyes.

METHODS

A single centre study which included 65 previously completely vitrectomized eyes of 62 patients who underwent cataract surgery. Patients were randomly divided into 3 groups. Patients received PE, and intraocular lens (IOL) implantation with the assistance of iris hook (Synergeties™) as group A (25 eyes); patients who received PE assisted with a 25G pars plana irrigation as group B (20 eyes), and patients who received PE performed without the help of any instrument as group C (20 eyes). Main outcome measures were surgery duration, Ultrasound (U/S) total time, endothelial cell density (ECD), cumulative dissipated energy (CDE) and complications of the procedures.

RESULTS

With the help of iris hook, the patients in group A had the lowest ECD loss rate (0.07±0.03, 0.09±0.03, and 0.10±0.03, P<0.05), shortest CDE (12.2±4.1, 15.8±6.0, and 16.0±6.0, P<0.05) and U/S total time (36.6±13.0s, 46.3±16.4s, and 47.6±16.1s, P<0.05), and minimal incidence of complications. The longest surgery duration was in group B (19.4±1.6min) and maximum complications rate in group C (20% miosis, 10% posterior capsular tears, 5% zonular dialysis, 5% cystoid macular edema). While best-corrected visual acuity (BCVA), intraocular pressure (IOP) and ECD did not show a significant difference among the three groups.

CONCLUSION

Without prolonged surgery duration, the iris hook assistant method can minimize heat generation during surgery and incidence of complications, which transfer the challenged PE in vitrectomized eyes into a regular surgery. It does not need any change in the hydrodynamic parameters and in the bag PE technique, easy to operate even for junior surgeons.

Comparative spectrophotometer analysis of ultraviolet-light filtering, blue light-filtering and violet-light filtering intraocular lenses

Purpose

To compare the light transmittance property of 7 currently used intraocular lens models (IOLs) by spectrophotometer data.

Materials and methods

Light-transmission spectra of 7 IOL models were assessed with a spectrophotometer. The transmittance properties were analyzed in 1 nm units from 350 nm wavelength to 800 nm.

Results

Three UV filtering IOL models (ZCB00, XC1-SP, AT LISA 809M) showed nearly full transmittance of the light from 400 to 500 nm, while steeply attenuating light with shorter wavelengths in various degrees. Three blue-light filtering IOLs (yellow-tinted IOLs; XY1, SN60WF, TNFT00) showed a slow-sloped increase of light transmission between 400 to 500nm. Among the three, XY1 showed different degree of inclination, showing a steeper slope than SN60WF and TNFT00. The violet-light filtering IOL (ZFR00V) showed a rapid increase of the transmission at around 435 nm wavelength, which is similar to UV filtering IOLs.

Conclusions

The seven different IOLs measured showed different characteristics of light transmission depending on the properties of each material and color. Blue-light filtering IOLs tend to blocked a wide range of wavelength up to 500nm, but rather were not effective at the range of 400 to 430nm. Violet-light filtering IOL showed advantages in filtering the high-energy wavelength, around 430nm, having a potential risk to retina and allowing the transmission of useful blue and green wavelength which is necessary for a better scotopic contrast sensitivity.

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.

Management of Cataract in Patients with Age-Related Macular Degeneration

Cataract and age-related macular degeneration (AMD) are two of the most common eye diseases of aging. This review addresses the pre-operative, intra-operative, and post-operative considerations in managing cataract in patients with age-related macular degeneration. Surgery for visually significant cataracts in patients with AMD can substantially improve the quality of life and reduce the risk of falls. Pre-operative optical coherence tomography is now recommended where possible to identify pre-existing macula disease. Careful counselling of patients is required before cataract surgery, especially with respect to the expected visual outcome, intraocular lens choice and potential risks of surgery. Real-world data has suggested 6 months of intravitreal anti-VEGF therapy for neovascular AMD before cataract surgery is compatible with optimum long-term visual outcomes. Patients receiving intravitreal therapy for neovascular AMD should be advised of the slightly higher risk of intraoperative complications and the surgeon should be prepared to manage these during the operation. During cataract surgery, unnecessary light exposure should be avoided to reduce phototoxicity. Careful planning of intravitreal therapy for neovascular AMD just before cataract surgery allows the eye greater recovery time in the post-operative period before further planned intravitreal therapy.

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.

Effect of Blue Light Filtering Intraocular Lenses on Visual Perception

Background and Objectives: This retrospective consecutive case control study compares best-corrected visual acuity (BCVA), mesopic contrast sensitivity (CS), color vision, and glare between a group of eyes with blue-light-filtering intraocular lenses and another with UV-light-filtering intraocular lenses. Materials and Methods: We used Early Treatment Diabetic Retinopathy Study charts to compare BCVA, Rabin charts for mesopic CS testing, Oculus HMC Anomaloscope MR to test for chromatic discrimination, and Oculus Mesotest II to measure scotopic CS with glare. For analysis, we used descriptive statistics and compared means with parametric and non-parametric tests. The level of significance was set as α = 0.05. Results: For the group with the blue-light-filtering intraocular lens, the average results were BCVA = 0.96 (SD ± 0.09), CS = 1.78 log (SD ± 0.12), chromatic discrimination results M = 63.91 (SD ± 11.88), R = 60.07 (SD ± 7.89). For mesopic CS with glare, the group achieved on average 2.54 (SD ± 1.50) points out of 4. For the group with the UV-light-filtering intraocular lens, the average results were BCVA = 0.93 (SD ± 0.14), CS = 1.79 log (SD ± 0.13), chromatic discrimination results M = 65.38 (SD ± 17.14), R = 60.79 (SD ± 10.39). For mesopic CS with glare, this group achieved an average of 2.79 (SD ± 1.53) points out of 4. Conclusion: No significant differences (p > 0.05) were found in any of the tested parameters between the analyzed groups. Slight shift in color vision was observed, although not statistically significant.

[Advertising or information in ophthalmology? : Scientific evaluation of a YouTube sample]

BACKGROUND

Despite the liberalization of the Therapeutic Products Advertising Act, advertising that praises, misleads or compares is still contrary to the German professional conduct. In view of the increasing commitment of financial investors and the economization in ophthalmology, this study was initiated to examine and check which (advertising) statements are affected in openly accessible videos on the YouTube platform.

METHODS

Using the search terms "ophthalmologist" and "eye center" as well as predefined criteria (German origin, audio track with spoken text, duration >1 min), videos were identified and transcribed into an anonymized text version. Using a self-developed predefined questionnaire, the individual statements were then subjected to a critical review by three experts and clarity, relevance and completeness of the information were also assessed. At the same time, laypersons were asked how convincingly, comprehensibly and completely they assessed the information and whether they would want to be treated by the physicians.

RESULTS

Out of 68 videos 30 met the defined inclusion criteria. Of the videos 46% focused on procedures for refractive surgery. From the experts' point of view, at least 11.8% of the individual statements were completely wrong or only slightly correct. Over 80% of the videos presented information incompletely. Perioperative and postoperative complications were only mentioned by three films. Laypersons evaluated the texts very inconsistently and could not identify the videos that contained problematic statements as assessed by the ophthalmologists. Conflicts with the legal requirements for advertising, e.g. the use of lurid superlatives were found. A balanced presentation, such as alternatives to treatment procedures was rare. There was a great need to improve the comprehensibility for laymen.

CONCLUSION

Only a very small number of freely accessible videos provide scientifically founded and correct information. Until now, many ophthalmologists do not sufficiently consider the legal and moral requirements for advertising statements. Therefore, there may be negative effects on the professional image in the public eye and opportunities for health promotion remain unused.

Association between conventional or blue-light-filtering intraocular lenses and survival in bilateral cataract surgery patients

Circadian rhythms regulate adaptive alterations in mammalian physiology and are maximally entrained by the short wavelength blue spectrum; cataracts block the transmission of light, particularly blue light. Cataract surgery is performed with two types of intraocular lenses (IOL): (1) conventional IOL that transmit the entire visible spectrum and (2) blue-light-filtering (BF) IOL that block the short wavelength blue spectrum. We hypothesized that the transmission properties of IOL are associated with long-term survival. This retrospective cohort study of a 15-hospital healthcare system identified 9,108 participants who underwent bilateral cataract surgery; 3,087 were implanted with conventional IOL and 6,021 received BF-IOL. Multivariable Cox proportional hazards models that included several a priori determined subgroup and sensitivity analyses yielded estimates supporting that conventional IOL compared with BF-IOL may be associated with significantly reduced risk of long-term death. Confirming these differences and identifying any potential causal mechanisms await the conduct of appropriately controlled prospective translational trials.

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Risk of all-cause mortality in 9,108 patients after bilateral cataract surgery

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Comparison of conventional intraocular lenses to blue-light-filtering intraocular lenses

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Conventional lenses that transmit the entire visible spectrum may improve survival

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Glaucoma patients particularly may benefit from conventional intraocular lenses

A Review of Complicated Cataract in Retinitis Pigmentosa: Pathogenesis and Cataract Surgery

Retinitis pigmentosa (RP) is a set of inherited retinal degenerative diseases that affect photoreceptor and retinal pigment epithelial cells (RPEs), possibly associated with some ocular complications, including cataract. The complicated cataract formation is most likely the result of RP-related inflammation response, and the most common morphology category is posterior subcapsular cataract (PSC). Despite the absence of curative pharmacologic treatment, phacoemulsification with intraocular lens implantation to deal with opacification in the lens is preferred due to the considerable visual outcomes. However, the incidence of intraocular and postoperative complications is higher in RP patients than those without, including intraoperative phototoxic retinal damage, posterior capsular opacification (PCO), capsular contraction syndrome (CCS), pseudophakic cystoid macular edema (PCME), increased postoperative intraocular pressure (IOP), and intraocular lens (IOL) dislocation. Hence, it needs much attention to surgery progress and close follow-up. In this review, we discuss the current understanding of RP patients with complicated cataracts from morphology to potential pathogenesis to cataract surgical procedure and provide a concise description and the recommended management of related surgery complications to broaden the knowledge and lower the latent risks to yield better clinical outcomes.

Cross-sectional study of the association between cataract surgery and age-related macular degeneration in the era of phacoemulsification in the national health and nutrition examination survey 2005-2008

OBJECTIVE

To determine the association between cataract surgery and age-related macular degeneration (AMD) in a representative US sample.

DESIGN

Population-based, cross-sectional study.

SETTING

The US National Health and Nutrition Examination Survey 2005-2008.

PARTICIPANTS

A total of 5401 participants aged ≥40 years had information in cataract surgery status and gradable retinal photographs for right eyes.

METHODS

Cataract surgery status was obtained from questionnaire. Non-mydriatic fundus photographs were collected and AMD status was assessed. The associations between AMD and cataract surgery were evaluated in right eyes using logistic regression models.

RESULTS

Of 338 right eyes with any AMD, 107 right eyes (28.9%) had cataract surgery. After adjusting for multiple variables, there were significant associations between cataract surgery and any AMD (OR 1.36; 95% CI 1.03 to 1.81) or late AMD (OR 2.48; 95% CI 1.01 to 6.09). No significant association was found between cataract surgery and early AMD after adjusting for multiple covariates (OR 1.20; 95% CI 0.91 to 1.59).

CONCLUSION

Our results suggest that cataract surgery is associated with the presence of AMD, particularly for late AMD. Longitudinal studies investigating the risk and progression of AMD after cataract surgery are needed in the era of phacoemulsification.

Influence of Intraocular Lens Asphericity and Blue Light Filtering on Visual Outcome, Contrast Sensitivity, and Aberrometry after Uneventful Cataract Extraction

Purpose

To evaluate the effect of asphericity and blue light filter (BLF) of three different intraocular lenses (IOLs) on the visual performance, second- and third-order aberrations (defocus, coma, trefoil), and contrast sensitivity after uneventful cataract surgery.

Methods

One hundred and twenty eyes of 60 patients with clinically significant cataract were randomly assigned to receive one of the three IOL types: Bioline Yellow Accurate (aspheric, with BLF, i-medical, Germany), BioAcryl 60125 (spherical, without BLF, Biotech, France), and H65C/N (aspheric, without BLF, PhysIOL, Belgium). Each IOL was implanted in 40 eyes. Complete ophthalmologic examination, functional acuity contrast testing and wavefront analysis were performed 60 days postoperatively.

Results

The mean postoperative best-corrected visual acuity (BCVA) was 0.95 ± 0.08, not differing statistically among the IOL groups (P = 0.83). Mean defocus and coma values did not yield any statistically significant difference through the IOL groups varying from –0.784 to –0.614 μm and 0.129 to 0.198 μm (P = 0.79 and 0.34, respectively). Bioline Yellow Accurate IOL presented less trefoil aberrations, 0.108 ± 0.05 μm, compared to the other two IOL types (BioAcryl [0.206 ± 0.19 μm] and Physiol [0.193 ± 0.17 μm], P< 0.05). Contrast sensitivity values did not differ among the groups under all lighting conditions. Bioline Yellow IOL showed a statistically higher loss of contrast sensitivity (between mesopic and mesopic with glare conditions) compared to the BioAcryl and PhysIOL in 12 and 3 cpd spatial frequencies, respectively (P< 0.05).

Conclusion

Bioline Yellow IOL indicated lower contrast sensitivity under mesopic conditions when glare was applied but resulted in less trefoil aberrations after uneventful cataract surgery. No further differences were noted in postoperative visual performance among three IOL groups.

Effects of ultraviolet and blue-light filtering on sleep: a meta-analysis of controlled trials and studies on cataract patients

PURPOSE

Two types of intraocular lenses (IOLs), namely ultraviolet-filtering IOL (UVF-IOL) and blue-light-filtering IOL (BF-IOL), are used to replace the aging lens in cataract patients. This provides a clinical scenario to investigate the BF and UVF effects on circadian rhythm. We revisited this topic and conducted an updated meta-analysis investigating the effects of UVF-IOL and BF-IOL on sleep quality.

METHODS

A literature search was conducted using the PubMed, Embase, and Cochrane Library databases, and finally, four randomized controlled trials, one nonrandomized controlled study, and two cohort studies were included in this meta-analysis.

RESULTS

The fixed-effect model revealed a significantly larger sleep quality improvement in the UVF-IOL group than in the BF-IOL group (standard mean difference [SMD] = 0.10, 95% confidence interval [CI]: 0.00-0.21) at 3-8 weeks but not 7-12 months after IOL implantation (SMD = 0.03, 95% CI: -0.08 to 0.13). The random effects model revealed no difference between groups at 3-8 weeks (SMD = 0.16, 95% CI: -0.07 to 0.39) and 7-12 months (SMD = 0.03, 95% CI: -0.08 to 0.13) after IOL implantation.

CONCLUSIONS

Our study found some weak evidence supporting that UVF-IOL implantation demonstrated a greater improvement in subjective sleep quality than the BF-IOL implantation only in a shorter period but not in a longer period. More trials should be conducted before further recommendations. Nevertheless, our study provides some insights into the effects of short wavelength electromagnetic radiation on the circadian rhythm. PROSPERO registration number: CRD42019128832.

Analysis of a Systematic Review About Blue Light-Filtering Intraocular Lenses for Retinal Protection: Understanding the Limitations of the Evidence

Importance

Cataract surgery, with intraocular lens (IOL) implantation, is the most common ocular surgical procedure worldwide. It has been suggested that IOLs that selectively attenuate short wavelength visible light (blue light-filtering IOLs) may be beneficial for macular health. Whether blue light-filtering IOLs impart retinal photoprotection is of public health relevance, particularly in the context of aging demographics and the increasing global prevalence of age-related macular degeneration. This review analyzes and interprets the key findings, including consideration of the implications for practice and future research, of a 2018 Cochrane systematic review that evaluated the efficacy and safety of blue light-filtering IOLs for providing protection to macular health and function.

Observations

The Cochrane systematic review included 51 randomized controlled trials that were performed in 17 countries. The trials involved adults undergoing cataract surgery in which a blue light-filtering IOL was compared with an equivalent non-blue light-filtering IOL. Study follow-up periods ranged from 1 month to 5 years. Together, these studies considered clinical outcomes in more than 5000 eyes. There was limited ability to combine data across trials (to draw overall conclusions) because of the use of different measurement techniques for outcomes, incomplete reporting of data, and/or varied follow-up periods. We identified substantial shortcomings in the internal validity of many of the included studies, particularly regarding trial design, conduct, and reporting. We propose several avenues for improving the rigor of potential future research in the field, including developing a core set of outcome measures, the inclusion of sample size calculations, the masking of trial participants and outcome assessors, and prospective clinical trial registration.

Conclusions and Relevance

Using blue light-filtering IOLs to impart benefits to the macula is currently not supported by the best available clinical research evidence, and it is important that clinicians are mindful of this evidence limitation when adopting these devices in clinical practice.

Retinal Neuron Is More Sensitive to Blue Light-Induced Damage than Glia Cell Due to DNA Double-Strand Breaks

Blue light is a major component of visible light and digital displays. Over-exposure to blue light could cause retinal damage. However, the mechanism of its damage is not well defined. Here, we demonstrate that blue light (900 lux) impairs cell viability and induces cell apoptosis in retinal neurocytes in vitro. A DNA electrophoresis assay shows severe DNA damage in retinal neurocytes at 2 h after blue light treatment. γ-H2AX foci, a specific marker of DNA double-strand breaks (DSBs), is mainly located in the Map2-posotive neuron other than the glia cell. After assaying the expression level of proteins related to DNA repair, Mre11, Ligase IV and Ku80, we find that Ku80 is up-regulated in retinal neurocytes after blue light treatment. Interestingly, Ku80 is mainly expressed in glia fibrillary acidic protein (GFAP)-positive glia cells. Moreover, following blue light exposure in vivo, DNA DSBs are shown in the ganglion cell layer and only observed in Map2-positive cells. Furthermore, long-term blue light exposure significantly thinned the retina in vivo. Our findings demonstrate that blue light induces DNA DSBs in retinal neurons, and the damage is more pronounced compared to glia cells. Thus, this study provides new insights into the mechanisms of the effect of blue light on the retina.

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.

Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances

PURPOSES

To evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality.

METHODS

Experiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18-30 yrs, middle-aged adults: 40-55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire.

RESULTS

All tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR-BT [-0.05, 0.05]; AR-BF [-0.05, 0.06]; BT-BF [-0.06, 0.06]) or without glare (95% CI: AR-BT [-0.01, 0.03]; AR-BF [-0.01, 0.03]; BT-BF [-0.02, 0.02]) and colour discrimination (95% CI: AR-BT [-9.07, 1.02]; AR-BF [-7.06, 4.46]; BT-BF [-3.12, 8.57]).

CONCLUSION

Blue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential blue-light hazard.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02821403.