title: Attenuating Photostress and Glare Disability in Pseudophakic Patients through the Addition of a Short-Wave Absorbing Filter Effect of Blue Light–Reducing Eye Glasses on Critical Flicker Frequency VISION WITH CHROMATIC FILTERS* Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances D‐15 Performance with Short Wavelength Absorbing Filters in Normals Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue. Amber lenses to block blue light and improve sleep: a randomized trial. Effect of variable tinted spectacle lenses on visual performance in control subjects.
abstract: To evaluate the effects of filtering short wavelength light on visual performance under intense light conditions among pseudophakic patients previously implanted with a clear intraocular lens ( IOL ) .  This was a patient-masked , r and omized crossover study conducted at 6 clinical sites in the United States between September 2013 and January 2014 . One hundred fifty-four bilaterally pseudophakic patients were recruited .  Photostress recovery time and glare disability thresholds were measured with clip-on blue-light-filtering and placebo ( clear ; no blue-light filtration ) glasses worn over patients ' habitual correction . Photostress recovery time was quantified as the time necessary to regain sight of a grating target after intense light exposure . Glare disability threshold was assessed as the intensity of a white-light annulus necessary to obscure a central target . The order of filter used and test eye were r and omized across patients . Photostress recovery time and glare disability thresholds were significantly improved ( both P < 0.0001 ) when patients used blue-light-filtering glasses compared with clear , nonfiltering glasses . Compared with a nonfiltering placebo , adding a clip-on blue-absorbing filter to the glasses of pseudophakic patients implanted with clear IOLs significantly increased their ability to cope with glare and to recover normal viewing after an intensive photostress . This result implies that IOL design s with blue-light-filtering characteristics may be beneficial under intense light conditions Purpose This study aims to evaluate the effect of blocking short-wavelength light on critical flicker frequency ( CFF ) . Design This study is a prospect i ve clinical study . Methods Thirty-three participants ( 17 men and 16 women ; age range , 28–39 years ) were divided into 3 groups . Each group wore 1 of 3 types of lenses while performing an intensive computer task for 2 hours . To evaluate the effect of blocking short-wavelength light before and after the task , we measured the CFF and evaluated subjective question naires . We used the analysis of variance test to examine whether the type of lenses tested affected any of the visual fatigue-related parameters . Results The type of lens worn significantly affected the CFF ; however , answers to the subjective question naires did not differ significantly between the groups . Two of the 13 question items showed a statistical difference between lens transparency and increase in the CFF ( lens 3 > lens 2 > lens 1 ) . Conclusions The higher the blocking effect of the lens , the lower the reduction in the CFF , suggesting that blocking short-wavelength light can reduce eye fatigue & NA ; Detection and resolution thresholds for blue and yellow targets against blue , green , and yellow background s were measured while wearing yellow and blue filters . Yellow filters improved thresholds for yellow targets against blue background s. Their effectiveness decreased ( i ) as the wavelength of the background increased , ( ii ) as the size of the target decreased , and ( iii ) with the age of the observer . The blue filters were generally ineffective . The results are for the most part explained on the basis of changes in target contrast brought about by the filters . The effectiveness of  yellow facemasks  for divers under certain conditions is discussed Purpose s 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-r and omized 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 st and ard and glare conditions , and colour discrimination were measured using st and ard clinical tests . After one month of lens wear , subjective ratings of lens performance were collected by question naire . 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 Clinical Trials.gov ABSTRACT Short wavelength absorbing filters ( SWAF 's ) have become very popular in the prescription and commercial sunglass markets . Like other chromatic filters SWAF 's have the potential to alter color vision . Performance on the Farnsworth Panel D‐15 ( D‐15 ) test was measured to determine whether any of 4 popular SWAF 's , in the form of sunglasses , produced color vision changes in 22 color normal adults . Using st and ard illuminant C , observers were tested under the following conditions : wearing no filter , a 1.0 log unit neutral density filter ( NDF ) , or one of the following SWAF 's : Corning CPF 550 ; NoIR Amber 40 % ; Blu Blocker ; and Vuarnet 4006 . In addition , the Vuarnets were tested outdoors in shaded daylight to determine the effects of increased illumination . The NDF served as the control and had no effect on D‐15 performance . Compared to it , only the Blu Blockers and Vuarnets affected D‐15 cap arrangements for these SWAF 's significantly . Blu Blocker error patterns had no predominant axis , whereas the predominant axis of errors in both Vuarnet conditions was tritan . Results of quantitative analysis performed on three factors confirmed these findings and indicated the Blu Blockers and Vuarnet SWAF 's caused moderate and moderate‐to‐severe levels of color confusion , respectively . Increasing the illumination level improved performance with the Vuarnets , but it remained significantly outside the normal range Purpose The purpose of this study was to determine whether subjects who wear short wavelength-blocking eyeglasses during computer tasks exhibit less visual fatigue and report fewer symptoms of visual discomfort than subjects wearing eyeglasses with clear lenses . Methods A total of 36 healthy subjects ( 20 male ; 16 female ) was r and omized to wearing no-block , low-blocking , or high-blocking eyeglasses while performing a 2-hour computer task . A masked grade r measured critical flicker fusion frequency ( CFF ) as a metric of eye fatigue and evaluated symptoms of eye strain with a 15-item question naire before and after computer use . Results We found that the change in CFF after the computer task was significantly more positive ( i.e. , less eye fatigue ) in the high-block versus the no-block ( P = 0.027 ) and low-block ( P = 0.008 ) groups . Moreover , r and om assignment to the high-block group but not to the low-block group predicted a more positive change in CFF ( i.e. , less eye fatigue ) following the computer task ( adjusted β = 2.310 ; P = 0.002 ) . Additionally , subjects wearing high-blocking eyeglasses reported significantly less feeling pain around/inside the eye ( P = 0.0063 ) , less feeling that the eyes were heavy ( P = 0.0189 ) , and less feeling that the eyes were itchy ( P = 0.0043 ) following the computer task , when compared to subjects not wearing high-blocking lenses . Conclusions Our results support the hypothesis that short-wavelength light-blocking eyeglasses may reduce eye strain associated with computer use based on a physiologic correlate of eye fatigue and on subjects ' reporting of symptoms typically associated with eye strain All light is not equal : blue wavelengths are the most potent portion of the visible electromagnetic spectrum for circadian regulation . Therefore , blocking blue light could create a form of physiologic darkness . Because the timing and quantity of light and darkness both affect sleep , evening use of amber lenses to block blue light might affect sleep quality . Mood is also affected by light and sleep ; therefore , mood might be affected by blue light blockade . In this study , 20 adult volunteers were r and omized to wear either blue-blocking ( amber ) or yellow-tinted ( blocking ultraviolet only ) safety glasses for 3 h prior to sleep . Participants completed sleep diaries during a one-week baseline assessment and two weeks ' use of glasses . Outcome measures were subjective : change in overall sleep quality and positive/negative affect . Results demonstrated that sleep quality at study outset was poorer in the amber lens than the control group . Two- by three-way ANOVA revealed significant ( p < .001 ) interaction between quality of sleep over the three weeks and experimental condition . At the end of the study , the amber lens group experienced significant ( p < .001 ) improvement in sleep quality relative to the control group and positive affect ( p = .005 ) . Mood also improved significantly relative to controls . A replication with more detailed data on the subjects ' circadian baseline and objective outcome measures is warranted PURPOSE To evaluate quantitatively the effects of tinted spectacle lenses on visual performance in individuals without visual pathology . METHODS Twenty-five subjects were assessed by measuring contrast sensitivity with and without glare . Gray , brown , yellow , green , purple , and blue lens tints were evaluated . Measurements were repeated with each lens tint and with a clear lens , and the order was counterbalanced within and between subjects . Glare was induced with a modified brightness acuity tester . RESULTS All subjects demonstrated an increase in contrast thresholds under glare conditions for all lens tints . However , purple and blue lens tints result ed in the least amount of contrast threshold increase ; the yellow lens tint result ed in the largest contrast threshold increase . CONCLUSIONS Purple and blue lens tints may improve contrast sensitivity in control subjects under glare conditions
target: A study involving normal participants found no observed difference in sleep quality .
  We found no studies investigating effects on macular structure or function .
  We find a lack of high quality evidence to support using BB spectacle lenses for the general population to improve visual performance or sleep quality , alleviate eye fatigue or conserve macular health
background: PURPOSE Blue-blocking ( BB ) spectacle lenses , which attenuate short-wavelength light , are being marketed to alleviate eyestrain and discomfort when using digital devices , improve sleep quality and potentially confer protection from retinal phototoxicity .
  The aim of this review was to investigate the relative benefits and potential harms of these lenses .