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

Investigating the effects of a blue-blocking software on the daily rhythm of sleep, melatonin, cortisol, positive and negative emotions

Since the use of light and electronic devices is inevitable, the use of blue light filters (in various light sources, electronic devices or optical devices including intraocular lenses) has been shown to improve sleep quality, especially in later hours of the day and during night time. In this study, we examine the effect of the blue light on sleep and wakefulness rhythms and positive and negative emotions. This randomized clinical trial was conducted with 80 AJA University of Medical Sciences employees who use computers at least 2 h a day. All subjects were employees of the discharge unit of Imam Reza Hospital, which is located next to AJA University. The subjects were divided into two groups of 40 people, blue light filter software intervention and sham treatment. Pittsburgh Sleep Quality Index (PSQI), Positive and Negative Affect Schedule (PANAS), Visual Function Questionnaire (VFQ), Epworth Sleepiness Scale (ESS) and salivary melatonin and cortisol levels were assessed for both groups before and 3 months after the intervention. Data analysis was performed using IBM SPSS statistics for windows, version 21.0 (Armonk, NY: IBM Corporation). P value ≤ 0.05 was considered as statistically significant. The results showed that the Pittsburgh sleep scale after the intervention was significantly lower in the intervention group than in the control group. After the intervention, the VFQ was significantly lower in the intervention group than in the control group (P = 0.018). There was no significant difference in the Epworth Sleepiness Scale (ESS) between the two study groups after the intervention (P = 0.370). There was no significant difference in Positive and Negative Affect Schedule (PANAS) in the two study groups after the intervention (P = 0.140). After the intervention, cortisol levels were significantly higher in the intervention group than in the control group (P = 0.006). Also, the amount of cortisol increased significantly in the intervention group (P = 0.028). The amount of melatonin decreased significantly in the intervention group (P = 0.034). The sleep quality score after the intervention was significantly lower in the intervention group than in the control group. This indicates better sleep quality in the intervention group. The results also show that the level of visual fatigue in the intervention group decreased significantly. However, no significant change was detected regarding positive and negative emotions. After the intervention, cortisol levels were significantly higher in the intervention group than the control group. In addition, cortisol levels increased significantly and melatonin levels decreased significantly in the intervention group during the course of study.

Association of clear vs blue-light filtering intraocular lenses with mental and behavioral disorders and diseases of the nervous system among patients receiving bilateral cataract surgery

PURPOSE

To analyze new-onset mental and behavioral disorders and nervous system diseases in patients with cataract implanted with either non-blue-light filtering (BLF) or BLF intraocular lenses (IOLs) in both eyes.

SETTING

Department of Ophthalmology, Kymenlaakso Central Hospital, Kotka, Finland.

DESIGN

A retrospective registry-based cohort study of patients operated between September 2007 and December 2018 who were followed until December 2021. We included 4986 patients who underwent bilateral cataract surgery.

METHODS

Patients were implanted with either non-BLF IOLs (N = 2609) or BLF IOLs (N = 2377) in both eyes. Follow-up before the first-eye surgery and between the first-eye and the second-eye surgery was performed to acknowledge the preexisting disorders and diseases. After the second-eye surgery, the groups were analyzed for the new-onset mental and behavioral disorders and diseases of the nervous system subcategorized by the International Classification of Diseases codes.

RESULTS

1707 male and 3279 female patients, aged 73.2 ± 8.6 years at the first-eye surgery and 74.3 ± 8.8 years at the second-eye surgery, were identified. In univariate log-rank tests, the use of BLF IOLs showed no association in overall new-onset disorders or diseases over non-BLF IOLs, in any subtype diagnosis codes except for sleep disorders, which favored BLF IOLs ( P = .003). A multivariate analysis adjusted for age and sex identified no associations in any new-onset disorders or diseases. Multivariate analysis of sleep disorders showed a nonsignificant advantage for BLF-IOLs (hazard ratio 0.756, 95% CI 0.534-1.070, P = .114).

CONCLUSIONS

BLF IOLs were not associated with mental and behavioral disorders or diseases of the nervous system.

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.

Cross-sectional study of intraocular cataract lens replacement, circadian rest–activity rhythms, and sleep quality in older adults

Study Objectives

Age-related cataract decreases light transmission at the most sensitive spectrum for circadian photoentrainment, with negative ramifications for human health. Here, we assessed whether intraocular lens replacement (IOL) in older patients with previous cataract was associated with increased stability and amplitude of circadian rest–activity rhythms, and improved sleep quality.

Methods

Our cross-sectional study included sixteen healthy older individuals without ocular diseases (controls; 55–80 years; 63.6 ± 5.6y; 8 women) and 13 patients with previous cataract and bilateral IOL (eight with blue-blocking [BB] lens and five with ultraviolet-only [UV] blocking lens; 55–80 years; 69.9 ± 5.2y; 9 women). The study comprised three weeks of at home rest–activity assessments using wrist-worn actigraphs, and each week preceded a laboratory protocol. Primary outcomes were actigraphy-derived interdaily stability, intradaily variability, and relative amplitude of circadian rest–activity rhythms. Secondary outcomes were actigraphy-assessed sleep quality (i.e. time in bed, sleep duration, sleep efficiency, mean wake bout time and fragmentation index).

Results

Patients with IOL had significantly higher interdaily stability (“Group” effect: pFDR =.001), but not intradaily variability (“Group” effect: pFDR = n.s.), and significantly higher relative amplitude of rest–activity rhythms (“Group” effect: pFDR &lt; .001). Moreover, patients with IOL had significantly higher activity levels during the day and lower levels during the evening, as compared to healthy older controls (“Group” effect: pFDR = .03). Analyses of actigraphy-derived sleep parameters yielded no significant differences across groups (“Group” effect: all pFDR &gt; .1).

Conclusions

Our cross-sectional study suggests that enhancing spectral lens transmission in patients with cataract may benefit their circadian health.

Brain Functional Network Architecture Reorganization and Alterations of Positive and Negative Affect, Experiencing Pleasure and Daytime Sleepiness in Cataract Patients after Intraocular Lenses Implantation

Background: Cataracts are associated with progressive blindness, and despite the decline in prevalence in recent years, it remains a major global health problem. Cataract extraction is reported to influence not only perception, attention and memory but also daytime sleepiness, ability to experience pleasure and positive and negative affect. However, when it comes to the latter, the magnitude and prevalence of this effect still remains uncertain. The current study aims to evaluate the hemodynamic basis of daytime sleepiness, ability to experience pleasure and positive and negative affect in cataract patients after the intraocular lens (IOL) implantation. Methods: Thirty-four cataract patients underwent resting-state functional magnetic resonance imaging evaluation before and after cataract extraction and intraocular lens implantation. Both global and local graph metrics were calculated in order to investigate the hemodynamic basis of excessive sleepiness (ESS), experiencing pleasure (SHAPS) as well as positive and negative affect (PANAS) in cataract patients. Results: Eigenvector centrality and clustering coefficient alterations associated with cataract extraction are significantly correlated with excessive sleepiness, experiencing pleasure as well as positive and negative affect. Conclusions: The current study reveals the hemodynamic basis of sleepiness, pleasure and affect in patients after cataract extraction and intraocular lens implantation. The aforementioned mechanism constitutes a proof for changes in functional network activity associated with postoperative vision improvement.

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

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.

Sleep and mood changes in advanced age after blue-blocking (yellow) intra ocular lens (IOLs) implantation during cataract surgical treatment: a randomized controlled trial

OBJECTIVES

Both advanced age and depression are characterized by changes in sleep patterns. Light exposure is one of the main synchronizers of circadian cycles and influences sleep by inhibiting melatonin secretion, which is mostly sensitive to light of low wavelengths (blue). Blue-blocking (yellow) intraocular lenses (IOLs) have supplanted the usual UV-blocking (clear) IOLs during cataract surgery to prevent age-related macular degeneration, however, the impact of yellow IOLs on sleep and mood is unclear. The purpose of this study was to compare the effects of yellow and clear IOLs on sleep and mood in aged patients undergoing bilateral cataract surgery.

METHODS

A randomized controlled superiority study was conducted within three ophthalmic surgical wards in France. A total of 204 subjects (mean age 76.2 ± 7.5 years) were randomized into yellow or clear IOLs groups. Patients completed a sleep diary, the pictorial sleepiness scale and the Beck Depression Inventory (BDI) one week before and eight weeks after the last surgical procedure.

RESULTS

According to an Intent To Treat (ITT) analysis, no significant difference was found between yellow and clear IOLs groups regarding sleep time, sleep latency, total sleep duration, quality of sleep and BDI scores. The rate of patients whose BDI score increased at the cutoff score of ≥5 after surgery was significantly higher in the yellow IOL group (n = 11, 13.1%) compared with the clear IOL group (n = 4; 4.7%); p = 0.02.

CONCLUSIONS

Using yellow IOLs for cataract surgery doesn't significantly impact sleep but may induce mood changes in aging.

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.

Role of short-wavelength filtering lenses in delaying myopia progression and amelioration of asthenopia in juveniles

AIM

To evaluate the positive effects of blue-violet light filtering lenses in delaying myopia and relieving asthenopia in juveniles.

METHODS

Sixty ametropia juveniles (aged range, 11-15y) were randomized into two groups: the test group (30 children, 60 eyes), wearing blue-violet light filtering lenses; and the control group (30 children, 60 eyes), wearing ordinary aspherical lenses. Baseline refractive power of the affected eyes and axial length of the two groups was recorded. After 1-year, the patients underwent contrast sensitivity (glare and non-glare under bright and dark conditions), accommodation-related testing, asthenopia questionnaire assessment, and adverse reaction questionnaire assessment.

RESULTS

After 1y of wearing the filtering lenses, changes in refractive power and axial length were not significantly different between the two groups (P>0.05). Under bright conditions, the contrast sensitivities at low and medium-frequency grating (vision angles of 6.3°, 4.0°, and 2.5°) with glare in the test group were significantly higher than in the control group (P<0.05), while the contrast sensitivity at low-frequency grating (vision angles of 6.3° and 4.0°) in the absence of glare in the test group was higher than in the control group (P<0.05). Under glare and non-glare dark conditions, the contrast sensitivities of various frequencies in the test group did not show significant differences compared with those in the control group (P>0.05). In the test group, the amplitude of accommodation, accommodative lag, and accommodative sensitivity of patients wearing glasses for 6 and 12mo were significantly elevated (P<0.05), while the asthenopia gratings were significantly decreased (P<0.05). Nevertheless, in the control group, the amplitude of accommodation, accommodative lag, and accommodative sensitivity after 12mo were not significantly altered compared with baseline (P>0.05), and the asthenopia grating was not significantly decreased (P>0.05). In addition, after wearing glasses for 6 to 12mo, the asthenopia grating of patients in the test group decreased significantly compared with the control group (P<0.05). At 12mo, the constituent ratio of adverse reactions did not show significant difference between the two groups (P>0.05).

CONCLUSION

A 1-year follow-up reveal that compare with ordinary glasses, short-wavelength filtering lenses (blue/violet-light filters) increase the low- and medium-frequency contrast sensitivity under bright conditions and improved accommodation. They effectively relieved asthenopia without severe adverse reactions, suggesting potential for clinical application. However, no significant advantages in terms of refractive power or axial length progression were found compared with ordinary aspheric lenses.

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

PURPOSE

To compare the long-term effect on circadian photoentrainment and sleep in patients implanted with neutral and blue-blocking intraocular lenses 1 year after cataract surgery.

METHODS

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.

RESULTS

One year after surgery, peak melatonin concentration was 3.3 pg/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) 1 year after surgery. Objective sleep quality was also improved as the time of wakefulness after sleep onset had improved by 5 min (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.

CONCLUSION

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 evidence informing the surgeon's selection of intraocular lens on the basis of light transmittance properties

In recent years, manufacturers and distributors have promoted commercially available intraocular lenses (IOLs) with transmittance properties that filter visible short-wavelength (blue) light on the basis of a putative photoprotective effect. Systematic literature review. Out of 21 studies reporting on outcomes following implantation of blue-light-filtering IOLs (involving 8914 patients and 12 919 study eyes undergoing cataract surgery), the primary outcome was vision, sleep pattern, and photoprotection in 9 (42.9%), 9 (42.9%), and 3 (14.2%) respectively, and, of these, only 7 (33.3%) can be classed as high as level 2b (individual cohort study/low-quality randomized controlled trials), all other studies being classed as level 3b or lower. Of the level 2b studies, only one (14.3%) found in favor of blue-light-filtering IOLs vs ultraviolet (UV)-only filtering IOLs on the basis of an association between better post-operative contrast sensitivity (CS) at select frequencies with the former; however, that study did not measure or report CS preoperatively in either group, and the finding may simply reflect better preoperative CS in the eyes scheduled to be implanted with the blue-light-filtering IOL; moreover, that study failed to measure macular pigment, a natural preceptoral filter of blue-light, augmentation of which is now known to improve CS. In terms of photoprotection, there is no level 2b (or higher) evidence in support of blue filtering IOLs vs UV-only filtering IOLs. On the basis of currently available evidence, one cannot advocate for the use of blue-light-filtering IOLs over UV-only filtering IOLs.

The effect of lens aging and cataract surgery on circadian rhythm

Many organisms have evolved an approximately 24-hour circadian rhythm that allows them to achieve internal physiological homeostasis with external environment. Suprachiasmatic nucleus (SCN) is the central pacemaker of circadian rhythm, and its activity is entrained to the external light-dark cycle. The SCN controls circadian rhythm through regulating the synthesis of melatonin by pineal gland via a multisynaptic pathway. Light, especially short-wavelength blue light, is the most potent environmental time cue in circadian photoentrainment. Recently, the discovery of a novel type of retinal photoreceptors, intrinsically photosensitive retinal ganglion cells, sheds light on the mechanism of circadian photoentrainment and raises concerns about the effect of ocular diseases on circadian system. With age, light transmittance is significantly decreased due to the aging of crystalline lens, thus possibly resulting in progressive loss of circadian photoreception. In the current review, we summarize the circadian physiology, highlight the important role of light in circadian rhythm regulation, discuss about the correlation between age-related cataract and sleep disorders, and compare the effect of blue light- filtering intraocular lenses (IOLs) and ultraviolet only filtering IOLs on circadian rhythm.

Effect of cataract surgery on regulation of circadian rhythms

This review looked at the effect of cataract surgery on the regulation of circadian rhythms and compared the effect of blue light-filtering and clear intraocular lenses (IOLs) on circadian rhythms. A systematic review and metaanalysis were performed, and the level of evidence was evaluated based on the principles described in the Grading of Recommendations Assessment, Development, and Evaluation system. A literature search of PubMed, Embase, and Cochrane Library databases was performed, as well as a search for unpublished trials at the U.S. National Institutes of Health Clinical Trials web site. Trials that reported the effect of cataract surgery on circadian rhythms were included. Outcomes were the Pittsburgh Sleep Quality Index (PSQI) global score, number of poor sleepers, Epworth Sleepiness Score, sleep efficiency, and mean concentration of melatonin. Cataract surgery improved regulation of circadian rhythms measured by the PSQI questionnaire, but the clinical relevance is uncertain. There was no difference between the effect of the 2 IOL types.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Mitigating Stress and Supporting Health in Deprived Urban Communities: The Importance of Green Space and the Social Environment

Environment-health research has shown significant relationships between the quantity of green space in deprived urban neighbourhoods and people’s stress levels. The focus of this paper is the nature of access to green space (i.e., its quantity or use) necessary before any health benefit is found. It draws on a cross-sectional survey of 406 adults in four communities of high urban deprivation in Scotland, United Kingdom. Self-reported measures of stress and general health were primary outcomes; physical activity and social wellbeing were also measured. A comprehensive, objective measure of green space quantity around each participant’s home was also used, alongside self-report measures of use of local green space. Correlated Component Regression identified the optimal predictors for primary outcome variables in the different communities surveyed. Social isolation and place belonging were the strongest predictors of stress in three out of four communities sampled, and of poor general health in the fourth, least healthy, community. The amount of green space in the neighbourhood, and in particular access to a garden or allotment, were significant predictors of stress. Physical activity, frequency of visits to green space in winter months, and views from the home were predictors of general health. The findings have implications for public health and for planning of green infrastructure, gardens and public open space in urban environments.

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

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

The Photobiology of Lutein and Zeaxanthin in the Eye

Lutein and zeaxanthin are antioxidants found in the human retina and macula. Recent clinical trials have determined that age- and diet-related loss of lutein and zeaxanthin enhances phototoxic damage to the human eye and that supplementation of these carotenoids has a protective effect against photoinduced damage to the lens and the retina. Two of the major mechanisms of protection offered by lutein and zeaxanthin against age-related blue light damage are the quenching of singlet oxygen and other reactive oxygen species and the absorption of blue light. Determining the specific reactive intermediate(s) produced by a particular phototoxic ocular chromophore not only defines the mechanism of toxicity but can also later be used as a tool to prevent damage.

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

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

Rejuvenation effects of cataract surgery with ultraviolet blocking intra-ocular lens on circadian rhythm and gait speed

BACKGROUND

Previously, we reported improvements in sleep quality and gait speed after implantation of a yellow-colored, blue light-blocking intra-ocular lens (IOL). This study evaluated systemic health parameters for 7 months after cataract surgery with implantation of a clear, ultraviolet (UV)-blocking IOL.

METHODS

A total of consecutive 71 patients (average age 74.1 years) underwent cataract surgery with the implantation of a clear, UV-blocking IOL. Participants were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the National Eye Institute Visual Function Questionnaire (VFQ-25) before and at 2 and 7 months after surgery. Four-meter gait speed was also determined. The metabolic parameters of serum glycated hemoglobin (HbA1c), triglycerides (TGs), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were tested.

RESULTS

The pre-operative and post-operative (2 and 7 months after surgery) results were 66.4±16.5, 79.5±12.6, and 81.0±13.0 for VFQ-25 score, 5.7±3.5, 5.1±3.1, and 4.8±2.9 for PSQI, and 0.90±0.22, 0.91±0.22, and 0.92±0.22 meters/sec for gait speed. Significant improvements following surgery were noted in the VFQ-25 score for all cases and in the PSQI for poor sleepers (preoperative PSQI >5.5) (P<0.05, paired t-test). The gait speed and metabolic parameters showed no significant changes.

CONCLUSIONS

Cataract surgery with implantation of an UV-blocking clear IOL has the potential for improving circadian rhythm and systemic health parameters.

Color of intra-ocular lens and cataract type are prognostic determinants of health indices after visual and photoreceptive restoration by surgery

Background: This study compared post-operative quality of life and sleep according to the type of cataract opacity and color of the implanted intra-ocular lens (IOL).

Methods: This is a cohort study and participants were 206 patients (average age 74.1 years) undergoing cataract surgery with the implantation of a clear ultra-violet (UV)-blocking IOL (C) or a yellow blue-light-blocking IOL (Y). Participants were evaluated using the National Eye Institute Visual Function Questionnaire (VFQ-25) and Pittsburgh Sleep Quality Index (PSQI) before surgery and 2 and 7 months after surgery. Changes in sub-scale scores of VFQ-25 and PSQI were compared.

Results: Sub-scale analyses for improvement after surgery revealed significant differences in ocular pain scores on the VFQ-25 (Y>C; the higher the score, the better the outcome). Furthermore, there were significant differences between the two IOLs in terms of the sleep latency score (C>Y) and sleep disturbances score (C>Y). A posterior sub-capsular cataract was significantly correlated with improvements in ocular pain and sleep latency scores. These effects were successfully represented by the change in scores rather than absolute post-operative scores because individual standard of response may often change after intervention, recognized as a response shift phenomenon in patient-reported outcome study. Regarding seasonal differences, patients who had surgery in summer exhibited relatively better sleep quality than those who had surgery in winter.

Conclusions: Analysis of sub-scales of health indices demonstrated characteristic prognoses for each IOL and cataract type. Cataract surgery may potentially contribute to systemic health in older adults.

Unilateral persistent hyperplastic primary vitreous: intensive management approach with excellent outcome beyond visual maturation

Persistent hyperplastic primary vitreous (PHPV) is an ocular developmental disorder resulting from incomplete apoptosis of the embryonic hyaloid vasculature. Unilateral PHPV is traditionally associated with a poor prognosis because of the challenges associated with managing progressive anisometropic amblyopia. We report a child with unilateral PHPV who underwent cataract extraction, primary posterior capsulotomy with anterior vitrectomy and intraocular lens implantation followed by combined trabeculectomy/trabeculotomy within the first 8 weeks of life. Intensive optometric and orthoptic input was required for many years to manage the increasing anisometropic amblyopia with final visual acuity of 20/40 unaided in the affected eye and without evidence of glaucomatous optic neuropathy. This case illustrates the excellent visual outcome possible in a child with complex, unilateral PHPV using an intensive management approach comprising: early surgical intervention for congenital cataract and secondary glaucoma, meticulous monitoring of refraction, visual acuity and intraocular pressure and motivated parents who engaged in the management.