Impact of blue-light filtering intraocular lens implantation on the quality of sleep in patients after cataract surgery

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

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

Transmittance characteristics of transparent hydrophobic acrylic foldable intraocular lenses that were in vivo for a prolonged period of time: A UV visible spectrophotometric study

PURPOSE

To record experimental data on the spectral transmittance characteristics of transparent hydrophobic acrylic foldable IOLs, which were in vivo for a prolonged period of time and explanted under clinical indications and also to compare the data with that of corresponding control and crystalline lens along with review of the relevant literature.

METHOD

Material and make of each of the explanted intraocular lenses (IOLs) as well as pre-explantation clinical status of the eyes were confirmed from the medical record. The transmittance of wavelength from 185 to 900 nm of each of the selected IOLs was measured using Shimadzu UV 2600 UV visible (UV-Vis) spectrophotometer in double-beam configuration and probe version 2.16 software. The data obtained were statistically analyzed.

RESULTS

The mean transmittance of 12 clinically explanted IOLs at spectral range 300-700 nm was 49.5% ± SD 6.9%. This value was 10% and 38% less than the corresponding clear (59% ± SD 0.4%) and yellow (87.5% ± SD 0.4%) control, respectively. The mean transmittance of the analytes in the UV range was 43.3 ± SD 6.9%, and it was almost similar to the control. The data showed wide variations without good correlation, and it matches with the human crystalline lens at the age range of 50-60 years. All eyes were otherwise healthy, and none had age-related macular degeneration.

CONCLUSION

In comparison with fresh IOL with a yellow filter, light transmittance at the spectral range 300-700 nm was found decreased in all the IOLs, which were in vivo for an average period of 12.25 ± 4.4 years. All IOLs transmitted variable amounts of UV radiation. More data are required for further analysis on the subject.

Effect of Blue Light-Filtering Intraocular Lenses on Insomnia After Cataract Surgery: A Nationwide Cohort Study With 10-Year Follow-up

PURPOSE

To compare the incidence of clinically diagnosed insomnia after cataract surgery in pseudophakic eyes with blue light-filtering intraocular lenses (BF-IOLs) and non-BF-IOLs.

DESIGN

Nationwide cohort study using the Taiwan National Health Insurance Research Database.

METHODS

We enrolled 171,415 patients who underwent cataract surgery in both eyes between 2008 and 2013 and followed them till 2018. Propensity score matching (PSM) was used to balance the baseline characteristics between the 2 IOL groups. The Cox model and cause-specific hazard model were used to estimate the hazard ratios (HRs) and subdistribution hazard ratio (SHR).

RESULTS

Overall, 19,604 (11.4%) and 151,811 (88.6%) patients had BF-IOL and non-BF-IOL implants, respectively. The BF-IOL group tended to be younger and had fewer chronic diseases. Within a mean follow-up period of 6.2 years, the incidence rates of insomnia (per 100 person-years) in the BF-IOL and non-BF-IOL groups were 2.97 and 3.21, respectively. There was no significant difference in the incidence rate of insomnia between the 2 IOL groups after treating all-cause mortality as a competing risk (SHR 0.98, 95% CI 0.95-1.01) and after PSM (HR 0.97, 95% CI 0.92-1.01), respectively. Subgroup analysis revealed no significant difference in the insomnia rate between the 2 IOL groups for various age groups, 2 sex groups, and men with and without benign prostatic hyperplasia.

CONCLUSION

In Taiwan, the use of a BF-IOL for up to 10 years had no apparent disadvantage over non-BF-IOLs with respect to insomnia.

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.

Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial

OBJECTIVES

Evening blue light has been shown to suppress melatonin, which can negatively impact sleep quality. The impact of evening blue light blocking (BLB) interventions on sleep remains ambiguous due to lack of randomized control trials. The present study tests the hypothesis that BLB glasses improve subjective and objective sleep in a population of healthy adults.

DESIGN

Two-week, randomized, controlled, crossover design.

SETTING

At-home testing of individuals in Michigan and Montana.

PARTICIPANTS

Twenty healthy adults (11 men, 9 women, age: 32 ± 12, body mass index: 28 ± 4 kg/m²).

INTERVENTION

Following a 1-week run-in baseline (ie, no glasses), participants were randomized to 1-week of BLB or control (ie, clear lens) glasses. Upon finishing the 1-week intervention, participants crossed over to the opposite condition. In both conditions, glasses were worn for 7 consecutive days from 6 PM until bedtime.

MEASUREMENTS

Objective sleep parameters were obtained using wrist actigraphy. Subjective sleep measures were assessed using sleep diaries. Karolinska Sleep Diaries were used to assess perceived sleep quality.

RESULTS

BLB reduced subjective sleep onset (21 ± 28 vs 24 ± 21 minute, P = .033) and awakenings (1.6 ± 1.0 vs 2.2 ± 1.0 awakenings, P = .019) compared to the control condition. In contrast, objective measures of sleep were not significantly impacted. In fact, our primary outcome variable of total sleep time (TST) tended to be paradoxically shorter in the BLB condition for both subjective (468 ± 45 vs 480 ± 48 minute, P = .066) and objective (433 ± 40 vs 449 ± 39 minute, P = .075) TST.

CONCLUSIONS

Blue light blocking glasses did not improve objective measures of sleep time or quality in healthy adults.

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.

Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep: A systematic review and meta-analysis

The sleep-wake and circadian cycles are influenced by light, particularly in the short-wavelength portion of the visible spectrum. Most personal light-emitting electronic devices are enriched in this so-called "blue" light. Exposure to these devices in the evening can disturb sleep. Interventions to reduce short-wavelength light exposure before bedtime may reduce adverse effects on sleep. We conducted a systematic review and meta-analysis to examine the effect of wearing color-tinted lenses (e.g. orange or amber) in frames to filter short-wavelength light exposure to the eye before nocturnal sleep. Outcomes were self-reported or objective measures of nocturnal sleep. Relatively few (k = 12) studies have been done. Study findings were inconsistent, with some showing benefit and others showing no effect of intervention. Meta-analyses yielded a small-to-medium magnitude combined effect size for sleep efficiency (Hedge's g = 0.31; 95% CI: -0.05, 0.66; I2 = 38.16%; k = 7), and a small-to-medium combined effect size for total sleep time (Hedge's g = 0.32; 95% CI: 0.01, 0.63; I2 = 12.07%; k = 6). For self-report measures, meta-analysis yielded a large magnitude combined effects size for Pittsburgh Sleep Quality Index ratings (Hedge's g = -1.25; 95% CI: -2.39, -0.11; I2 = 36.35%; k = 3) and a medium combined effect size for total sleep time (Hedge's g = 0.51; 95% CI: 0.18, 0.84; I2 = 0%; k = 3), Overall, there is some, albeit mixed, evidence that this approach can improve sleep, particularly in individuals with insomnia, bipolar disorder, delayed sleep phase syndrome, or attention-deficit hyperactive disorder. Considering the ubiquitousness of short-wavelength-enriched light sources, future controlled studies to examine the efficacy of this approach to improve sleep are warranted. Systematic review registration: PROSPERO 2018 CRD42018105854.

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.

Melanopsin-Mediated Acute Light Responses Measured in Winter and in Summer: Seasonal Variations in Adults with and without Cataracts

Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs. winter. Fifty-two participants (mean age 67.4 years; 30 with bilateral cataracts and 22 age-matched controls with clear lenses; pseudophakes) were tested twice, once in summer and once in winter. At each test session we assessed the electroretinogram and pupil responses during daytime and we determined melatonin suppression, subjective sleepiness and mood in response to light exposure in the evening. Circadian rest-activity cycles and sleep from activity recordings were also analyzed for both seasons. Both groups had similar visual function. There were no seasonal differences in the electroretinogram. For the pupil responses to bright blue light, the post-illumination pupil response (PIPR) was greater in winter than summer in pseudophakes, but not in cataract participants, whereas melatonin suppression to acute light exposure showed no differences between both groups and seasons. Overall, intra-daily variability of rest-activity was worse in winter but participants felt sleepier and reported worse mood at the laboratory in evening time in the summer. Those with cataracts had poorer sleep quality with lower sleep efficiency, and higher activity during sleep in winter than summer. In this study, the PIPR showed a seasonal variation in which a larger response was found during winter. This variation was only detected in participants with a clear intraocular lens. In the cataract group, visual function was not impaired yet these participants showed a lack of seasonal changes in the pupil response to blue light and poorer sleep in winter. These findings raise the question for tailored lighting conditions for cataract patients in order to counter potentially deleterious effects of living with chronically lower light exposure.