- Email: [email protected]
Blue light–filtering and violet light–filtering hydrophobic acrylic foldable intraocular lenses: Intraindividual comparison
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Blue light–filtering and violet light–filtering hydrophobic acrylic foldable intraocular lenses: Intraindividual comparison Shinichiro Nakano, MD, Akira Miyata, MD, Junya Kizawa, MD, Daijiro Kurosaka, MD, Kazunori Miyata, MD, Tetsuro Oshika, MD
Purpose: To compare the clinical outcomes after cataract surgery and implantation of a blue light–filtering IOL (AcrySof IQ SN60WF) or a violet light–filtering intraocular lens (IOL) (OptiBlue ZCB00V). Setting: Four surgical sites in Japan. Design: Prospective case series. Methods: One eye of patients with bilateral cataract was randomly allocated to the blue light–filtering IOL and the fellow eye to the violet light–filtering IOL. Visual acuity and contrast sensitivity were assessed over 3 months. The incidence of cyanopsia was evaluated using the neutralization method. Results: The study enrolled 110 eyes of 55 patients. There was no significant difference in visual acuity between the two IOLs. Based
I
n our natural environments, the most offending portions of the electromagnetic spectrum are ultraviolet (UV) radiation (200 to 400 nm) and the blue-light portion of the visible spectrum (400 to 500 nm). More precisely, the blue-light portion comprises violet light (400 to 440 nm) and blue light (440 to 500 nm).1–3 The human cornea filters UV light of less than 300 nm.4 The normal crystalline lens absorbs UV light up to 400 nm.5 The aging crystalline lens, which gradually becomes yellow, reduces the transmission of the short-wavelength part of visible light.6 These protective effects of the crystalline lens are lost when the cataract is removed and an intraocular lens (IOL) without an appropriate chromophore is implanted, potentially increasing the risk for retinal damage from hazardous light.
on the neutralization results 1 week postoperatively, 15 cases (27.8%) with the light–filtering IOL and 8 cases (14.8%) with the violent light–filtering IOL had cyanopsia; the difference reached statistical significance (P Z .049). After 2 weeks, the difference in the incidence of cyanopsia was not significant. Postoperative contrast sensitivity under photopic condition at 1 week and 3 months and contrast sensitivity under mesopic conditions at 3 months were significantly better with the violet light–filtering IOL than with the blue light–filtering IOL (P < .05).
Conclusions: The violet light–filtering IOL yielded highly satisfactory clinical outcomes, including reduction of cyanopsia and a potential improvement in contrast sensitivity. The different chromophores of the IOL and its different material and design might have contributed. J Cataract Refract Surg 2019; 45:1393–1397 Q 2019 ASCRS and ESCRS
Ultraviolet light–filtering chromophores are incorporated into most IOLs available today. Blue light–filtering (yellowtinted) IOLs, which mimic the natural color of the human crystalline lens, have been widely used over the past few decades; these IOLs attenuate blue-light radiation (440 to 500 nm) and shorter wavelength optical radiation.7,8 However, because the most harmful component of visible light is the violet wavelength (400 to 440 nm), violet light–filtering IOLs were developed to reduce retinal exposure to UV radiation and violet light.9,10 Even though violet light–filtering IOLs have been widely used in some markets for a while, to our knowledge the clinical outcomes have not been reported. We performed this study to compare the 3-month clinical results of two hydrophobic acrylic foldable IOLs, a blue light– filtering model and a violet light–filtering model.
Submitted: March 14, 2019 | Final revision submitted: April 22, 2019 | Accepted: May 21, 2019 From the Division of Ophthalmology (Nakano), Ryugasaki Saiseikai Hospital, and Department of Ophthalmology (Oshika), Faculty of Medicine, University of Tsukuba, Ibaraki, Miyata Eye Clinic (A. Miyata), Hiroshima, Department of Ophthalmology (Kizawa, Kurosaka), Iwate Medical University, and Miyata Eye Hospital (K. Miyata), Miyazaki, Japan. Corresponding author: Tetsuro Oshika, MD, Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan. Email: [email protected]. Q 2019 ASCRS and ESCRS Published by Elsevier Inc.
0886-3350/$ - see frontmatter https://doi.org/10.1016/j.jcrs.2019.05.027
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aberrations with a 4.0 mm pupil were measured with a ShackHartmann wavefront analyzer (KR-1W, Topcon Co.). The incidence and degree of cyanopsia were assessed with the neutralization method 1 week, 2 weeks, and 1 month postoperatively.12 The neutralization method uses a series of white gradation cards with an increasingly intense yellow tint. Six cards of varying intensity were presented, and the patients were asked to select the card that appears to be white. Those who selected 1 of the 3 cards with a more intense yellow tint were considered to have cyanopsia.12 The cards were presented at 40 cm in a light environment of approximately 1400 lux; a combination of a high color– rendering fluorescent lamp and a halogen lamp was used to simulate natural sunlight conditions. The light source for the testing environment was a high color–rendering fluorescent lamp.
PATIENTS AND METHODS This prospective multicenter intraindividual study enrolled patients with bilateral senile cataract scheduled for phacoemulsification and IOL implantation. The institutional review boards at all sites approved the study protocol, and all patients provided written informed consent. The study adhered to the tenets of the Declaration of Helsinki and was registered with the University Hospital Medical Information Network Clinical Trials Registry (identification #UMIN000009929).A Patients who matched the study inclusion criteria were selected from the clinic population. Patients were not included if they had a history of eye surgery or ocular disease that may affect the surgical results. Intraocular Lenses This study assessed the AcrySof IQ SN60WF blue light–filtering IOL (Alcon Laboratories, Inc.), and the OptiBlue ZCB00V violet light–filtering IOL (Johnson & Johnson Vision, Inc.). Both are single-piece acrylic foldable IOLs with a 6.0 mm diameter optic of and a 13.0 mm overall length. The spectral transmittance characteristics of the IOLs have been reported.10 The blue light– filtering IOL blocks 67% of violet light and 27% of blue light, while the violet light–filtering IOL blocks 90% and 6%, respectively.10 One eye of each patient was randomly assigned to the blue light–filtering IOL and the contralateral eye to the violet light– filtering IOL. Randomization was performed using a sealedenvelope method. The patients and those performing the clinical examinations were not informed of which IOL was implanted in which eye. All eyes were targeted for emmetropia.
Statistical Analysis A power calculation using a significance level of 5% (a) and a power of 80% (1 b) showed that a sample size of 41 patients (82 eyes) would be required to detect a clinically relevant difference in contrast sensitivity and in the presence and degree of cyanopsia. Statistical analysis was performed using SPSS Statistics for Windows software (version 25, IBM Corp.). Numerical data were compared between groups using the paired t test. The chisquare test (Fisher exact test) was used to assess the significance of differences in the incidence of cyanopsia between the 2 IOL groups. A P value less than 0.05 was considered statistically significant.
RESULTS The study enrolled 110 eyes of 55 patients; all completed the 3-month follow-up examination. The mean power of the implanted blue light–filtering IOLs and violet light– filtering IOLs was 20.9 G 3.1 diopters (D) and 21.2 G 3.0 D, respectively. Throughout the 3-month follow-up, there was no significant difference in the manifest refraction (Table 1) or corrected distance visual acuity (Table 2) between the two IOL groups. No patient reported subjective differences in color perception between his or her two eyes. Contrast sensitivity under photopic conditions was significantly better 1 week and 3 months postoperatively in the violet light–filtering IOL group than in the blue light–filtering IOL group (Figure 1). Contrast sensitivity under mesopic conditions was significantly better 3 months postoperatively with the violet light–filtering IOL than with the blue light–filtering IOL (Figure 2). Ocular aberrations were measured in 27 cases at two sites. The spherical aberration tended to be lower with the violet light–filtering IOLs (mean 0.017 G 0.037 mm) than with the blue light–filtering IOLs (mean 0.032 G 0.042 mm);
Surgical Technique Four surgeons at 4 surgical sites participated in this study. Surgeries were performed using a standard phacoemulsification technique through a 2.4 mm or 2.75 mm incision. The incision sizes in the eyes of the same patient were similar. An anterior capsulorhexis approximately 5.0 mm in diameter was created, and the IOL was implanted in the capsular bag using an injector. Direct observation showed that all IOLs were implanted within the intact continuous capsulorhexis. No sutures were placed to close the incisions. Examinations The manifest refraction and corrected distance visual acuity were measured preoperatively and 1 day, 1 week, 2 weeks, 1 month, and 3 months postoperatively. The contrast sensitivity under photopic conditions (85.0 candelas/m2) and mesopic conditions (3.0 candelas/m2) was assessed at 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree using the Optec 6500 Vision Tester (Stereo Optical Co.) 1 week, 1 month, and 3 months postoperatively. The test was performed monocularly with undilated pupils at 2.5 m with full spectacle correction. From the data obtained with Optec 6500 device, the area under the log contrast sensitivity function was calculated using a previously described method.11 Ocular higher-order
Table 1. Manifest refraction. Mean (D) ± SD Postoperative IOL Blue-filtering Violet-filtering
Preoperative 0.20 G 3.03 0.34 G 3.23
IOL Z intraocular lens
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1 Day 0.20 G 0.89 0.27 G 0.80
1 Week 0.33 G 0.77 0.42 G 0.73
2 Weeks 0.33 G 0.77 0.41 G 0.79
1 Month 0.32 G 0.80 0.35 G 0.84
3 Months 0.30 G 0.83 0.30 G 0.95
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Table 2. Corrected distance visual acuity (logMAR). Mean (LogMAR) ± SD Postoperative IOL Blue-filtering Violet-filtering
Preoperative
1 Day
0.283 G 0.340 0.258 G 0.223
0.011 G 0.123 0.001 G 0.097
1 Week
2 Weeks
0.038 G 0.088 0.054 G 0.066
0.045 G 0.082 0.046 G 0.084
1 Month 0.044 G 0.077 0.059 G 0.066
3 Months 0.056 G 0.070 0.066 G 0.059
IOL Z intraocular lens; LogMAR Z logarithm of the minimum angle of resolution
the difference did not reach statistical significance (P Z .181). The mean coma aberration was 0.080 G 0.050 mm with violet light–filtering IOLs and 0.080 G 0.051 mm with blue light–filtering IOLs; the difference was not significant (P Z .990). Cyanopsia test results were available for 54 patients. One week postoperatively, cyanopsia was detected in 15 patients (27.8%) in the blue light–filtering group and 8 patients (14.8%) in the violet light–filtering IOL group. The difference was statistically significant (P Z .049). The difference in the incidence of cyanopsia was not significant 2 weeks after surgery (14 eyes [25.9%] and 9 eyes [16.7%], respectively) (P Z .174). At 1 month, 12 eyes (22.2%) in the blue light–filtering group and 9 eyes (16.7%) in the violet light–filtering group had cyanopsia (P Z .314). DISCUSSION To our knowledge, this is the first study to compare the clinical outcomes of blue light–filtering and violet light– filtering hydrophobic acrylic foldable IOLs. The goal was not to compare the effects of blue-light filtering and violet-light filtering per se. In addition to the difference chromophores used to filter light, the two IOLs in our study have many different characteristics, such as the refractive index, shape and design, biomaterial, amount of spherical aberrations, and Abbe number (chromatic aberration). Valid comparison of the effects of the light filters themselves requires a comparison between two IOLs with different chromophores but based on an identical IOL platform. Such a study design, however, was not possible because of the limited commercial availability of these types of IOLs; for example, clear and yellow versions of the OptiBlue ZCB00V IOL are not available in our country. Moreover, intraindividual comparison of tinted IOLs and untinted IOLs is difficult to design for ethical reasons. Thus, in the current study we attempted to evaluate the clinical outcomes of violet light–filtering IOLs and compare them with one of the most commonly used blue light– filtering IOLs on the market. In other words, the current study compared two commercial products rather than two different filtering options. In the current study, both blue light–filtering IOLs and violet light–filtering IOLs yielded a highly stable postoperative manifest refraction and very satisfactory visual acuity results. On the other hand, contrast sensitivity was significantly better with the violet light–filtering IOLs than with
the blue light–filtering IOLs. Zigman13 reported that short-wavelength lighting enhances light scattering, chromatic aberration, and fluorescence and that contrast and visual clarity in human vision and in photography are improved when cutoff filters are used to eliminate environmental light with wavelengths shorter than 450 nm. The effects of eliminating the short wavelength light could, at least in part, explain our results. In addition, it has been reported that UV radiation and violet light can cause significant phototoxicity but contribute little to rod-mediated visual function, while blue light is vital for scotopic vision.3,9 In a psychophysical study,14 filtering blue light in addition to violet light reduced scotopic sensitivity. In contrast, a study by Mojzis et al.15 comparing a plate-haptic IOL (CT Asphina 404V, Carl Zeiss Meditec AG) with an violet-light filter that suppresses violet light transmittance in the range of 400 to 440 nm and a C-loop blue light–filtering (yellow-tinted) IOL (AcrySof IQ SN60WF, Alcon) found that the yellow-tinted IOL provided significantly better photopic and mesopic contrast sensitivity at some frequencies, probably because of better optimization of spherical aberration. In our study, postoperative ocular spherical aberrations tended to be smaller with the violet light–filtering IOL than with the blue light–filtering IOL. Moreover, Nakajima et al.16 found that longitudinal chromatic aberration was smaller in eyes with the OptiBlue ZCB00V IOL than with other yellow-tinted IOLs. They performed a simulation study of the modulation transfer function or a visual Strehl ratio computed on the basis of an optical transfer function (visual Strehl optical transfer function). The differences in chromatic dispersions of different IOLs had a smaller impact on visual function when monochromatic aberrations existed to some extent but that the small chromatic dispersion markedly improved visual performance when the amount of monochromatic aberration was small. Negishi et al.17 evaluated pseudophakic eyes with several type of IOLs and found that longitudinal chromatic aberration of some IOLs degraded the quality of retinal images. Similar findings were obtained in simulation studies using human eye models.18,19 These factors, including monochromatic and chromatic aberrations, could have contributed to the difference in contrast sensitivity between the two IOLs tested in our study. Cyanopsia, which is also referred to as blue vision, is a form of chromatopsia. Cyanopsia is associated with the Volume 45 Issue 10 October 2019
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Figure 1. Area under the log contrast sensitivity function calculated from contrast sensitivity measurements under photopic conditions in the blue light–filtering IOL group (solid line) and the violet light– filtering IOL group (dotted line) (* Z P ! .05, paired t test; AULCSF Z area under the log contrast sensitivity function; IOL Z intraocular lens).
Figure 2. Area under the log contrast sensitivity function calculated from contrast sensitivity measurements under mesopic conditions in the blue light–filtering IOL group (solid line) and the violet light– filtering IOL group (dotted line) (* Z P ! .05, paired t test; AULCSF Z area under the log contrast sensitivity function; IOL Z intraocular lens).
subjective perception that everything is tinted with a blue hue of varying degrees. In the current study, we used the neutralization method to evaluate the presence and severity the degree of cyanopsia; this is a very sensitive semiquantitative test.12 The number of eyes with cyanopsia was significantly lower in the violet light–filtering IOL group than in the blue light–filtering IOL group 1 week postoperatively; the difference became statistically insignificant at 2 weeks and remained so at 3 months. Thus, the difference in cyanopsia between the two IOLs was transient and not severe. The potential difference in color perception between the two eyes of each patient was explained as part of the preoperative informed consent process, and the study protocol was approved by the institutional review board at all surgical sites. Clinically, however, patients did not report different color perception between their two eyes at any point after surgery. Several previous studies12,20,21 found a lower incidence of cyanopsia after cataract surgery and implantation of IOLs with a yellow chromophore compared with implantation of clear IOLs. Cyanopsia appears in the early period after cataract surgery and tends to resolve within a few weeks.12,21,22 In a comparative study of clear IOLs and yellow IOLs,21 cyanopsia resolved by 3 months postoperatively, implying that color constancy or neural adaptation had taken place. Another study assessed cyanopsia with achromatic-point settings at several timepoints starting 1 day before cataract surgery22; color perception during cyanopsia was recalibrated by neural mechanisms within several hours. Two studies23,24 reported that the different spectral transmittance was the main explanation for subjective complaints about color vision after implantation of a yellow IOL in one eye and a clear IOL in the other eye. Until now, cyanopsia after cataract surgery has been attributed
to the different blue light–cutting features of the cataractous crystalline lens versus the implanted IOLs.12 The two IOLs used in our study have significantly different spectral transmittance; the blue light–filtering IOL blocks 67% of violet light and 27% of blue light, while the violet light–filtering IOL suppresses 90% and 6%, respectively.10 The violet light–filtering IOL induced less cyanopsia after surgery, indicating that violet light, rather than blue light, plays a major role in the development of cyanopsia. Many studies of tinted IOLs have been performed. There are two approaches to the filtrating of visible light by IOLs; that is, filtering visible light to the blue part of the spectrum (400 to 500 nm) or limiting the violet part of the spectrum (400 to 450 nm) only and allowing transmission of blue light.25 Violet light is reported to be less important to rod-mediated vision but has higher phototoxicity than blue light.26,27 There has been an argument about whether IOLs should transmit blue light for optimum scotopic vision and circadian photoreception.3 It has been reported that the response of nonvisual retinal ganglion photoreceptors to bright, properly timed light exposures helped ensure effective circadian photoentrainment and optimum diurnal physiologic processes.28 The spectral sensitivity of circadian photoreception peaks in the blue part of the spectrum at approximately 460 nm. Retinal illumination decreases with aging because of pupil miosis. Inadequate environmental light and/or ganglion photoreception can cause circadian disruption, increasing the risk for insomnia, depression, and numerous systemic disorders.28 Optimum IOL designs should consider the spectral requirements of both conscious and unconscious retinal photoreception. Detailed analysis of this topic is beyond the scope of our study, however. Nonetheless, the current study found that the violet light–filtering IOL gave highly satisfactory clinical outcomes while
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reducing cyanopsia and potentially improving contrast sensitivity after surgery.
WHAT WAS KNOWN Blue light–filtering (yellow-tinted) intraocular lenses (IOLs) mimicking natural coloring of the human crystalline lens are widely used. They attenuate blue and shorter wavelength optical radiation. The blue-light portion of the visible spectrum (400 to 500 nm) comprises violet light (400 to 440 nm) and blue lights (440 to 500 nm).
WHAT THIS PAPER ADDS Violet light–filtering IOLs, which filter 400 to 440 nm of the wavelength spectrum, reduced the incidence and severity of cyanopsia after surgery. The IOL evaluated with a violet light–filtering chromophore has a potential to improve contrast sensitivity; the different spectral transmittance and IOL material and design might contribute to this.
REFERENCES 1. Begaj T, Schaal S. Sunlight and ultraviolet radiationdpertinent retinal implications and current management. Surv Ophthalmol 2018; 63:174–192 2. Glickman RD. Phototoxicity to the retina: mechanisms of damage. Int J Toxicol 2002; 21:473–490 3. Mainster MA, Turner PL. Blue-blocking IOLs decrease photoreception without providing significant photoprotection. Surv Ophthalmol 2010; 55:272–289 4. Doutch JJ, Quantock AJ, Joyce NC, Meek KM. Ultraviolet light transmission through the human corneal stroma is reduced in the periphery. Biophys J 2012; 102:1258–1264 5. Mellerio J. Yellowing of the human lens: nuclear and cortical contributions. Vision Res 1987; 27:1581–1587 6. Weale RA. Age and the transmittance of the human crystalline lens. J Physiol 1988; 395:577–587 7. Yang H, Afshari NA. The yellow intraocular lens and the natural ageing lens. Curr Opin Ophthalmol 2014; 25:40–43 8. Downes SM. Ultraviolet or blue-filtering intraocular lenses: what is the evidence? Eye 2016; 30:215–221 9. Mainster MA. Intraocular lenses should block UV radiation and violet but not blue light. Arch Ophthalmol 2005; 123:550–555 10. Mainster MA. Violet and blue light blocking intraocular lenses: photoprotection versus photoreception. Br J Ophthalmol 2006; 90:784–792 11. Applegate RA, Howland HC, Sharp RP, Cottingham AJ, Yee RW. Corneal aberrations and visual performance after radial keratotomy. J Refract Surg 1998; 14:397–407 12. Miyata A. Neutralization method for detecting the incidence of color perception changes after cataract surgery. J Cataract Refract Surg 2015; 41:764–770 13. Zigman S. Light filters to improve vision. Optom Vis Sci 1992; 69:325–328 14. Aarnisalo EA. Effects of yellow filter glasses on the results of photopic and scotopic photometry. Am J Ophthalmol 1988; 105:408–411 ~ero DP. Clinical 15. Mojzis P, Bombera Z, Vesela S, Klapuchova D, Ziak P, Pin comparative analysis of the outcomes with a yellow- and a violet-tinted intraocular lens [letter]. Int J Ophthalmol 2016; 9:166–169 16. Nakajima M, Hiraoka T, Yamamoto T, Takagi S, Hirohara Y, Oshika T, Mihashi T. Differences of longitudinal chromatic aberration (LCA) between eyes with intraocular lenses from different manufacturers. PLoS One 2016; 11 (6):e0156227 17. Negishi K, Ohnuma K, Hirayama N, Noda T. Policy-Based Medical Services Network Study Group for Intraocular Lens and Refractive Surgery. Effect of chromatic aberration on contrast sensitivity in pseudophakic eyes. Arch Ophthalmol 2001; 119:1154–1158 18. Weeber HA, Piers PA. Theoretical performance of intraocular lenses correcting both spherical and chromatic aberration. J Refract Surg 2012; 28:48–52
19. Song H, Yuan X, Tang X. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models. BMC Ophthalmol 2016; 16:9 20. Yuan Z, Reinach P, Yuan J. Contrast sensitivity and color vision with a yellow intraocular lens. Am J Ophthalmol 2004; 138:138–140 21. Hayashi K, Hayashi H. Visual function in patients with yellow tinted intraocular lenses compared with vision in patients with non-tinted intraocular lenses. Br J Ophthalmol 2006; 90:1019–1023 22. Kitakawa T, Nakadomari S, Kuriki I, Kitahara K. Evaluation of early state of cyanopsia with subjective color settings immediately after cataract removal surgery. J Opt Soc Am A Opt Image Sci Vis 2009; 26:1375–1381 23. Shah SA, Miller KM. Explantation of an Acrysof Natural intraocular lens because of a color vision disturbance. Am J Ophthalmol 2005; 140:941– 942 24. Olson MD, Miller KM. Implanting a clear intraocular lens in one eye and a yellow lens in the other eye: a case series. Am J Ophthalmol 2006; 141:957– 958 25. Edwards KH, Gibson GA. Intraocular lens short wavelength light filtering. Clin Exp Optom 2010; 93:390–399 26. Ham WT Jr, Mueller HA, Sliney DH. Retinal sensitivity to damage from short wavelength light. Nature 1976; 260:153–155 27. Mainster MA, Ham WT Jr, Delori FC. Potential retinal hazards; instrument and environmental light sources. Ophthalmology 1983; 90:927–932; discussion by T Lawwill, 931–932 28. Turner PL, Mainster MA. Circadian photoreception: ageing and the eye’s important role in systemic health. Br J Ophthalmol 2008; 92:1439–1444 OTHER CITED MATERIAL A. University Hospital Medical Information Network Clinical Trials. Prospective Observational Multicenter Study to Examine the Stability and Quality of the Visual Function After the Implantation of OptiBlue (ZCB00V). UMIN000009929. Available at: https://upload.umin.ac.jp/cgi-open-bin/ ctr_e/ctr_view.cgi?recptnoZR000011531. Accessed July 5, 2019
Disclosures: Drs. Nakano and Kizawa received personal fees and Drs. A. Miyata, Kurosaka, K. Miyata, and Oshika received grants and personal fees from Alcon Laboratories, Inc. and Johnson & Johnson Vision during the conduct of the study. Dr. Nakano received personal fees from Hoya Surgical Optics, Inc., and Kowa Co., Ltd. outside the submitted work. Dr. A. Miyata received personal fees from Carl Zeiss Meditec AG, Hoya Surgical Optics, Inc., Kowa Co., Ltd., Novartis Corp., and Santen Pharmaceutical Co., Ltd., outside the submitted work. Dr. Kizawa received grants and personal fees from Hoya Surgical Optics, Inc., Kowa Co., Ltd., Novartis Corp., and Santen Pharmaceutical Co., Ltd., outside the submitted work. Dr. Kurosaka received grants and personal fees from Kowa Co., Ltd. and Senju Pharmaceutical Co., Ltd.; personal fees from Hoya Surgical Optics, Inc., Otsuka Pharmaceutical Co., Ltd., and Santen Pharmaceutical Co., Ltd.; and grants from Nippon Ganka Iryocenter Co., Ltd., Novartis Corp., Pfizer, Inc., and Wakamoto Pharmaceutical Co., Ltd., outside the submitted work. Dr. K. Miyata received grants and personal fees from Hoya Surgical Optics, Inc., Otsuka Pharmaceutical Co., Ltd., Santen Pharmaceutical Co., Ltd., Senju Pharmaceutical Co., Ltd., and Wakamoto Pharmaceutical Co., Ltd.; grants from Becton Dickinson & Co., GlaxoSmithKline, Kissei Pharmaceutical Co., Ltd., Novartis Corp., Shionogi, Inc., and Sucampo Pharma, LLC; and personal fees from MSD, Pfizer, Inc., and STAAR Surgical Co. outside the submitted work. Dr. Oshika received grants from Kai Medical, Inc., Novartis Corp., Pfizer, Inc., and Topcon Corp.; personal fees from Japan Focus Co., Ltd., Mitsubishi Tanabe Pharma, and Otsuka Pharmaceutical Co., Ltd.; grants and personal fees from Hoya Surgical Optics, Inc., Kowa Co., Ltd., Santen Pharmaceutical Co., Ltd., and Senju Pharmaceutical Co., Ltd.; and personal fees and nonfinancial support from Tomey Corp. outside the submitted work.
First author: Shinichiro Nakano, MD Division of Ophthalmology, Ryugasaki Saiseikai Hospital, Ibaraki, Japan
Volume 45 Issue 10 October 2019
ARTICLE
Blue light–filtering and violet light–filtering hydrophobic acrylic foldable intraocular lenses: Intraindividual comparison Shinichiro Nakano, MD, Akira Miyata, MD, Junya Kizawa, MD, Daijiro Kurosaka, MD, Kazunori Miyata, MD, Tetsuro Oshika, MD
Purpose: To compare the clinical outcomes after cataract surgery and implantation of a blue light–filtering IOL (AcrySof IQ SN60WF) or a violet light–filtering intraocular lens (IOL) (OptiBlue ZCB00V). Setting: Four surgical sites in Japan. Design: Prospective case series. Methods: One eye of patients with bilateral cataract was randomly allocated to the blue light–filtering IOL and the fellow eye to the violet light–filtering IOL. Visual acuity and contrast sensitivity were assessed over 3 months. The incidence of cyanopsia was evaluated using the neutralization method. Results: The study enrolled 110 eyes of 55 patients. There was no significant difference in visual acuity between the two IOLs. Based
I
n our natural environments, the most offending portions of the electromagnetic spectrum are ultraviolet (UV) radiation (200 to 400 nm) and the blue-light portion of the visible spectrum (400 to 500 nm). More precisely, the blue-light portion comprises violet light (400 to 440 nm) and blue light (440 to 500 nm).1–3 The human cornea filters UV light of less than 300 nm.4 The normal crystalline lens absorbs UV light up to 400 nm.5 The aging crystalline lens, which gradually becomes yellow, reduces the transmission of the short-wavelength part of visible light.6 These protective effects of the crystalline lens are lost when the cataract is removed and an intraocular lens (IOL) without an appropriate chromophore is implanted, potentially increasing the risk for retinal damage from hazardous light.
on the neutralization results 1 week postoperatively, 15 cases (27.8%) with the light–filtering IOL and 8 cases (14.8%) with the violent light–filtering IOL had cyanopsia; the difference reached statistical significance (P Z .049). After 2 weeks, the difference in the incidence of cyanopsia was not significant. Postoperative contrast sensitivity under photopic condition at 1 week and 3 months and contrast sensitivity under mesopic conditions at 3 months were significantly better with the violet light–filtering IOL than with the blue light–filtering IOL (P < .05).
Conclusions: The violet light–filtering IOL yielded highly satisfactory clinical outcomes, including reduction of cyanopsia and a potential improvement in contrast sensitivity. The different chromophores of the IOL and its different material and design might have contributed. J Cataract Refract Surg 2019; 45:1393–1397 Q 2019 ASCRS and ESCRS
Ultraviolet light–filtering chromophores are incorporated into most IOLs available today. Blue light–filtering (yellowtinted) IOLs, which mimic the natural color of the human crystalline lens, have been widely used over the past few decades; these IOLs attenuate blue-light radiation (440 to 500 nm) and shorter wavelength optical radiation.7,8 However, because the most harmful component of visible light is the violet wavelength (400 to 440 nm), violet light–filtering IOLs were developed to reduce retinal exposure to UV radiation and violet light.9,10 Even though violet light–filtering IOLs have been widely used in some markets for a while, to our knowledge the clinical outcomes have not been reported. We performed this study to compare the 3-month clinical results of two hydrophobic acrylic foldable IOLs, a blue light– filtering model and a violet light–filtering model.
Submitted: March 14, 2019 | Final revision submitted: April 22, 2019 | Accepted: May 21, 2019 From the Division of Ophthalmology (Nakano), Ryugasaki Saiseikai Hospital, and Department of Ophthalmology (Oshika), Faculty of Medicine, University of Tsukuba, Ibaraki, Miyata Eye Clinic (A. Miyata), Hiroshima, Department of Ophthalmology (Kizawa, Kurosaka), Iwate Medical University, and Miyata Eye Hospital (K. Miyata), Miyazaki, Japan. Corresponding author: Tetsuro Oshika, MD, Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan. Email: [email protected]. Q 2019 ASCRS and ESCRS Published by Elsevier Inc.
0886-3350/$ - see frontmatter https://doi.org/10.1016/j.jcrs.2019.05.027
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aberrations with a 4.0 mm pupil were measured with a ShackHartmann wavefront analyzer (KR-1W, Topcon Co.). The incidence and degree of cyanopsia were assessed with the neutralization method 1 week, 2 weeks, and 1 month postoperatively.12 The neutralization method uses a series of white gradation cards with an increasingly intense yellow tint. Six cards of varying intensity were presented, and the patients were asked to select the card that appears to be white. Those who selected 1 of the 3 cards with a more intense yellow tint were considered to have cyanopsia.12 The cards were presented at 40 cm in a light environment of approximately 1400 lux; a combination of a high color– rendering fluorescent lamp and a halogen lamp was used to simulate natural sunlight conditions. The light source for the testing environment was a high color–rendering fluorescent lamp.
PATIENTS AND METHODS This prospective multicenter intraindividual study enrolled patients with bilateral senile cataract scheduled for phacoemulsification and IOL implantation. The institutional review boards at all sites approved the study protocol, and all patients provided written informed consent. The study adhered to the tenets of the Declaration of Helsinki and was registered with the University Hospital Medical Information Network Clinical Trials Registry (identification #UMIN000009929).A Patients who matched the study inclusion criteria were selected from the clinic population. Patients were not included if they had a history of eye surgery or ocular disease that may affect the surgical results. Intraocular Lenses This study assessed the AcrySof IQ SN60WF blue light–filtering IOL (Alcon Laboratories, Inc.), and the OptiBlue ZCB00V violet light–filtering IOL (Johnson & Johnson Vision, Inc.). Both are single-piece acrylic foldable IOLs with a 6.0 mm diameter optic of and a 13.0 mm overall length. The spectral transmittance characteristics of the IOLs have been reported.10 The blue light– filtering IOL blocks 67% of violet light and 27% of blue light, while the violet light–filtering IOL blocks 90% and 6%, respectively.10 One eye of each patient was randomly assigned to the blue light–filtering IOL and the contralateral eye to the violet light– filtering IOL. Randomization was performed using a sealedenvelope method. The patients and those performing the clinical examinations were not informed of which IOL was implanted in which eye. All eyes were targeted for emmetropia.
Statistical Analysis A power calculation using a significance level of 5% (a) and a power of 80% (1 b) showed that a sample size of 41 patients (82 eyes) would be required to detect a clinically relevant difference in contrast sensitivity and in the presence and degree of cyanopsia. Statistical analysis was performed using SPSS Statistics for Windows software (version 25, IBM Corp.). Numerical data were compared between groups using the paired t test. The chisquare test (Fisher exact test) was used to assess the significance of differences in the incidence of cyanopsia between the 2 IOL groups. A P value less than 0.05 was considered statistically significant.
RESULTS The study enrolled 110 eyes of 55 patients; all completed the 3-month follow-up examination. The mean power of the implanted blue light–filtering IOLs and violet light– filtering IOLs was 20.9 G 3.1 diopters (D) and 21.2 G 3.0 D, respectively. Throughout the 3-month follow-up, there was no significant difference in the manifest refraction (Table 1) or corrected distance visual acuity (Table 2) between the two IOL groups. No patient reported subjective differences in color perception between his or her two eyes. Contrast sensitivity under photopic conditions was significantly better 1 week and 3 months postoperatively in the violet light–filtering IOL group than in the blue light–filtering IOL group (Figure 1). Contrast sensitivity under mesopic conditions was significantly better 3 months postoperatively with the violet light–filtering IOL than with the blue light–filtering IOL (Figure 2). Ocular aberrations were measured in 27 cases at two sites. The spherical aberration tended to be lower with the violet light–filtering IOLs (mean 0.017 G 0.037 mm) than with the blue light–filtering IOLs (mean 0.032 G 0.042 mm);
Surgical Technique Four surgeons at 4 surgical sites participated in this study. Surgeries were performed using a standard phacoemulsification technique through a 2.4 mm or 2.75 mm incision. The incision sizes in the eyes of the same patient were similar. An anterior capsulorhexis approximately 5.0 mm in diameter was created, and the IOL was implanted in the capsular bag using an injector. Direct observation showed that all IOLs were implanted within the intact continuous capsulorhexis. No sutures were placed to close the incisions. Examinations The manifest refraction and corrected distance visual acuity were measured preoperatively and 1 day, 1 week, 2 weeks, 1 month, and 3 months postoperatively. The contrast sensitivity under photopic conditions (85.0 candelas/m2) and mesopic conditions (3.0 candelas/m2) was assessed at 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree using the Optec 6500 Vision Tester (Stereo Optical Co.) 1 week, 1 month, and 3 months postoperatively. The test was performed monocularly with undilated pupils at 2.5 m with full spectacle correction. From the data obtained with Optec 6500 device, the area under the log contrast sensitivity function was calculated using a previously described method.11 Ocular higher-order
Table 1. Manifest refraction. Mean (D) ± SD Postoperative IOL Blue-filtering Violet-filtering
Preoperative 0.20 G 3.03 0.34 G 3.23
IOL Z intraocular lens
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1 Day 0.20 G 0.89 0.27 G 0.80
1 Week 0.33 G 0.77 0.42 G 0.73
2 Weeks 0.33 G 0.77 0.41 G 0.79
1 Month 0.32 G 0.80 0.35 G 0.84
3 Months 0.30 G 0.83 0.30 G 0.95
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Table 2. Corrected distance visual acuity (logMAR). Mean (LogMAR) ± SD Postoperative IOL Blue-filtering Violet-filtering
Preoperative
1 Day
0.283 G 0.340 0.258 G 0.223
0.011 G 0.123 0.001 G 0.097
1 Week
2 Weeks
0.038 G 0.088 0.054 G 0.066
0.045 G 0.082 0.046 G 0.084
1 Month 0.044 G 0.077 0.059 G 0.066
3 Months 0.056 G 0.070 0.066 G 0.059
IOL Z intraocular lens; LogMAR Z logarithm of the minimum angle of resolution
the difference did not reach statistical significance (P Z .181). The mean coma aberration was 0.080 G 0.050 mm with violet light–filtering IOLs and 0.080 G 0.051 mm with blue light–filtering IOLs; the difference was not significant (P Z .990). Cyanopsia test results were available for 54 patients. One week postoperatively, cyanopsia was detected in 15 patients (27.8%) in the blue light–filtering group and 8 patients (14.8%) in the violet light–filtering IOL group. The difference was statistically significant (P Z .049). The difference in the incidence of cyanopsia was not significant 2 weeks after surgery (14 eyes [25.9%] and 9 eyes [16.7%], respectively) (P Z .174). At 1 month, 12 eyes (22.2%) in the blue light–filtering group and 9 eyes (16.7%) in the violet light–filtering group had cyanopsia (P Z .314). DISCUSSION To our knowledge, this is the first study to compare the clinical outcomes of blue light–filtering and violet light– filtering hydrophobic acrylic foldable IOLs. The goal was not to compare the effects of blue-light filtering and violet-light filtering per se. In addition to the difference chromophores used to filter light, the two IOLs in our study have many different characteristics, such as the refractive index, shape and design, biomaterial, amount of spherical aberrations, and Abbe number (chromatic aberration). Valid comparison of the effects of the light filters themselves requires a comparison between two IOLs with different chromophores but based on an identical IOL platform. Such a study design, however, was not possible because of the limited commercial availability of these types of IOLs; for example, clear and yellow versions of the OptiBlue ZCB00V IOL are not available in our country. Moreover, intraindividual comparison of tinted IOLs and untinted IOLs is difficult to design for ethical reasons. Thus, in the current study we attempted to evaluate the clinical outcomes of violet light–filtering IOLs and compare them with one of the most commonly used blue light– filtering IOLs on the market. In other words, the current study compared two commercial products rather than two different filtering options. In the current study, both blue light–filtering IOLs and violet light–filtering IOLs yielded a highly stable postoperative manifest refraction and very satisfactory visual acuity results. On the other hand, contrast sensitivity was significantly better with the violet light–filtering IOLs than with
the blue light–filtering IOLs. Zigman13 reported that short-wavelength lighting enhances light scattering, chromatic aberration, and fluorescence and that contrast and visual clarity in human vision and in photography are improved when cutoff filters are used to eliminate environmental light with wavelengths shorter than 450 nm. The effects of eliminating the short wavelength light could, at least in part, explain our results. In addition, it has been reported that UV radiation and violet light can cause significant phototoxicity but contribute little to rod-mediated visual function, while blue light is vital for scotopic vision.3,9 In a psychophysical study,14 filtering blue light in addition to violet light reduced scotopic sensitivity. In contrast, a study by Mojzis et al.15 comparing a plate-haptic IOL (CT Asphina 404V, Carl Zeiss Meditec AG) with an violet-light filter that suppresses violet light transmittance in the range of 400 to 440 nm and a C-loop blue light–filtering (yellow-tinted) IOL (AcrySof IQ SN60WF, Alcon) found that the yellow-tinted IOL provided significantly better photopic and mesopic contrast sensitivity at some frequencies, probably because of better optimization of spherical aberration. In our study, postoperative ocular spherical aberrations tended to be smaller with the violet light–filtering IOL than with the blue light–filtering IOL. Moreover, Nakajima et al.16 found that longitudinal chromatic aberration was smaller in eyes with the OptiBlue ZCB00V IOL than with other yellow-tinted IOLs. They performed a simulation study of the modulation transfer function or a visual Strehl ratio computed on the basis of an optical transfer function (visual Strehl optical transfer function). The differences in chromatic dispersions of different IOLs had a smaller impact on visual function when monochromatic aberrations existed to some extent but that the small chromatic dispersion markedly improved visual performance when the amount of monochromatic aberration was small. Negishi et al.17 evaluated pseudophakic eyes with several type of IOLs and found that longitudinal chromatic aberration of some IOLs degraded the quality of retinal images. Similar findings were obtained in simulation studies using human eye models.18,19 These factors, including monochromatic and chromatic aberrations, could have contributed to the difference in contrast sensitivity between the two IOLs tested in our study. Cyanopsia, which is also referred to as blue vision, is a form of chromatopsia. Cyanopsia is associated with the Volume 45 Issue 10 October 2019
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Figure 1. Area under the log contrast sensitivity function calculated from contrast sensitivity measurements under photopic conditions in the blue light–filtering IOL group (solid line) and the violet light– filtering IOL group (dotted line) (* Z P ! .05, paired t test; AULCSF Z area under the log contrast sensitivity function; IOL Z intraocular lens).
Figure 2. Area under the log contrast sensitivity function calculated from contrast sensitivity measurements under mesopic conditions in the blue light–filtering IOL group (solid line) and the violet light– filtering IOL group (dotted line) (* Z P ! .05, paired t test; AULCSF Z area under the log contrast sensitivity function; IOL Z intraocular lens).
subjective perception that everything is tinted with a blue hue of varying degrees. In the current study, we used the neutralization method to evaluate the presence and severity the degree of cyanopsia; this is a very sensitive semiquantitative test.12 The number of eyes with cyanopsia was significantly lower in the violet light–filtering IOL group than in the blue light–filtering IOL group 1 week postoperatively; the difference became statistically insignificant at 2 weeks and remained so at 3 months. Thus, the difference in cyanopsia between the two IOLs was transient and not severe. The potential difference in color perception between the two eyes of each patient was explained as part of the preoperative informed consent process, and the study protocol was approved by the institutional review board at all surgical sites. Clinically, however, patients did not report different color perception between their two eyes at any point after surgery. Several previous studies12,20,21 found a lower incidence of cyanopsia after cataract surgery and implantation of IOLs with a yellow chromophore compared with implantation of clear IOLs. Cyanopsia appears in the early period after cataract surgery and tends to resolve within a few weeks.12,21,22 In a comparative study of clear IOLs and yellow IOLs,21 cyanopsia resolved by 3 months postoperatively, implying that color constancy or neural adaptation had taken place. Another study assessed cyanopsia with achromatic-point settings at several timepoints starting 1 day before cataract surgery22; color perception during cyanopsia was recalibrated by neural mechanisms within several hours. Two studies23,24 reported that the different spectral transmittance was the main explanation for subjective complaints about color vision after implantation of a yellow IOL in one eye and a clear IOL in the other eye. Until now, cyanopsia after cataract surgery has been attributed
to the different blue light–cutting features of the cataractous crystalline lens versus the implanted IOLs.12 The two IOLs used in our study have significantly different spectral transmittance; the blue light–filtering IOL blocks 67% of violet light and 27% of blue light, while the violet light–filtering IOL suppresses 90% and 6%, respectively.10 The violet light–filtering IOL induced less cyanopsia after surgery, indicating that violet light, rather than blue light, plays a major role in the development of cyanopsia. Many studies of tinted IOLs have been performed. There are two approaches to the filtrating of visible light by IOLs; that is, filtering visible light to the blue part of the spectrum (400 to 500 nm) or limiting the violet part of the spectrum (400 to 450 nm) only and allowing transmission of blue light.25 Violet light is reported to be less important to rod-mediated vision but has higher phototoxicity than blue light.26,27 There has been an argument about whether IOLs should transmit blue light for optimum scotopic vision and circadian photoreception.3 It has been reported that the response of nonvisual retinal ganglion photoreceptors to bright, properly timed light exposures helped ensure effective circadian photoentrainment and optimum diurnal physiologic processes.28 The spectral sensitivity of circadian photoreception peaks in the blue part of the spectrum at approximately 460 nm. Retinal illumination decreases with aging because of pupil miosis. Inadequate environmental light and/or ganglion photoreception can cause circadian disruption, increasing the risk for insomnia, depression, and numerous systemic disorders.28 Optimum IOL designs should consider the spectral requirements of both conscious and unconscious retinal photoreception. Detailed analysis of this topic is beyond the scope of our study, however. Nonetheless, the current study found that the violet light–filtering IOL gave highly satisfactory clinical outcomes while
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reducing cyanopsia and potentially improving contrast sensitivity after surgery.
WHAT WAS KNOWN Blue light–filtering (yellow-tinted) intraocular lenses (IOLs) mimicking natural coloring of the human crystalline lens are widely used. They attenuate blue and shorter wavelength optical radiation. The blue-light portion of the visible spectrum (400 to 500 nm) comprises violet light (400 to 440 nm) and blue lights (440 to 500 nm).
WHAT THIS PAPER ADDS Violet light–filtering IOLs, which filter 400 to 440 nm of the wavelength spectrum, reduced the incidence and severity of cyanopsia after surgery. The IOL evaluated with a violet light–filtering chromophore has a potential to improve contrast sensitivity; the different spectral transmittance and IOL material and design might contribute to this.
REFERENCES 1. Begaj T, Schaal S. Sunlight and ultraviolet radiationdpertinent retinal implications and current management. Surv Ophthalmol 2018; 63:174–192 2. Glickman RD. Phototoxicity to the retina: mechanisms of damage. Int J Toxicol 2002; 21:473–490 3. Mainster MA, Turner PL. Blue-blocking IOLs decrease photoreception without providing significant photoprotection. Surv Ophthalmol 2010; 55:272–289 4. Doutch JJ, Quantock AJ, Joyce NC, Meek KM. Ultraviolet light transmission through the human corneal stroma is reduced in the periphery. Biophys J 2012; 102:1258–1264 5. Mellerio J. Yellowing of the human lens: nuclear and cortical contributions. Vision Res 1987; 27:1581–1587 6. Weale RA. Age and the transmittance of the human crystalline lens. J Physiol 1988; 395:577–587 7. Yang H, Afshari NA. The yellow intraocular lens and the natural ageing lens. Curr Opin Ophthalmol 2014; 25:40–43 8. Downes SM. Ultraviolet or blue-filtering intraocular lenses: what is the evidence? Eye 2016; 30:215–221 9. Mainster MA. Intraocular lenses should block UV radiation and violet but not blue light. Arch Ophthalmol 2005; 123:550–555 10. Mainster MA. Violet and blue light blocking intraocular lenses: photoprotection versus photoreception. Br J Ophthalmol 2006; 90:784–792 11. Applegate RA, Howland HC, Sharp RP, Cottingham AJ, Yee RW. Corneal aberrations and visual performance after radial keratotomy. J Refract Surg 1998; 14:397–407 12. Miyata A. Neutralization method for detecting the incidence of color perception changes after cataract surgery. J Cataract Refract Surg 2015; 41:764–770 13. Zigman S. Light filters to improve vision. Optom Vis Sci 1992; 69:325–328 14. Aarnisalo EA. Effects of yellow filter glasses on the results of photopic and scotopic photometry. Am J Ophthalmol 1988; 105:408–411 ~ero DP. Clinical 15. Mojzis P, Bombera Z, Vesela S, Klapuchova D, Ziak P, Pin comparative analysis of the outcomes with a yellow- and a violet-tinted intraocular lens [letter]. Int J Ophthalmol 2016; 9:166–169 16. Nakajima M, Hiraoka T, Yamamoto T, Takagi S, Hirohara Y, Oshika T, Mihashi T. Differences of longitudinal chromatic aberration (LCA) between eyes with intraocular lenses from different manufacturers. PLoS One 2016; 11 (6):e0156227 17. Negishi K, Ohnuma K, Hirayama N, Noda T. Policy-Based Medical Services Network Study Group for Intraocular Lens and Refractive Surgery. Effect of chromatic aberration on contrast sensitivity in pseudophakic eyes. Arch Ophthalmol 2001; 119:1154–1158 18. Weeber HA, Piers PA. Theoretical performance of intraocular lenses correcting both spherical and chromatic aberration. J Refract Surg 2012; 28:48–52
19. Song H, Yuan X, Tang X. Effects of intraocular lenses with different diopters on chromatic aberrations in human eye models. BMC Ophthalmol 2016; 16:9 20. Yuan Z, Reinach P, Yuan J. Contrast sensitivity and color vision with a yellow intraocular lens. Am J Ophthalmol 2004; 138:138–140 21. Hayashi K, Hayashi H. Visual function in patients with yellow tinted intraocular lenses compared with vision in patients with non-tinted intraocular lenses. Br J Ophthalmol 2006; 90:1019–1023 22. Kitakawa T, Nakadomari S, Kuriki I, Kitahara K. Evaluation of early state of cyanopsia with subjective color settings immediately after cataract removal surgery. J Opt Soc Am A Opt Image Sci Vis 2009; 26:1375–1381 23. Shah SA, Miller KM. Explantation of an Acrysof Natural intraocular lens because of a color vision disturbance. Am J Ophthalmol 2005; 140:941– 942 24. Olson MD, Miller KM. Implanting a clear intraocular lens in one eye and a yellow lens in the other eye: a case series. Am J Ophthalmol 2006; 141:957– 958 25. Edwards KH, Gibson GA. Intraocular lens short wavelength light filtering. Clin Exp Optom 2010; 93:390–399 26. Ham WT Jr, Mueller HA, Sliney DH. Retinal sensitivity to damage from short wavelength light. Nature 1976; 260:153–155 27. Mainster MA, Ham WT Jr, Delori FC. Potential retinal hazards; instrument and environmental light sources. Ophthalmology 1983; 90:927–932; discussion by T Lawwill, 931–932 28. Turner PL, Mainster MA. Circadian photoreception: ageing and the eye’s important role in systemic health. Br J Ophthalmol 2008; 92:1439–1444 OTHER CITED MATERIAL A. University Hospital Medical Information Network Clinical Trials. Prospective Observational Multicenter Study to Examine the Stability and Quality of the Visual Function After the Implantation of OptiBlue (ZCB00V). UMIN000009929. Available at: https://upload.umin.ac.jp/cgi-open-bin/ ctr_e/ctr_view.cgi?recptnoZR000011531. Accessed July 5, 2019
Disclosures: Drs. Nakano and Kizawa received personal fees and Drs. A. Miyata, Kurosaka, K. Miyata, and Oshika received grants and personal fees from Alcon Laboratories, Inc. and Johnson & Johnson Vision during the conduct of the study. Dr. Nakano received personal fees from Hoya Surgical Optics, Inc., and Kowa Co., Ltd. outside the submitted work. Dr. A. Miyata received personal fees from Carl Zeiss Meditec AG, Hoya Surgical Optics, Inc., Kowa Co., Ltd., Novartis Corp., and Santen Pharmaceutical Co., Ltd., outside the submitted work. Dr. Kizawa received grants and personal fees from Hoya Surgical Optics, Inc., Kowa Co., Ltd., Novartis Corp., and Santen Pharmaceutical Co., Ltd., outside the submitted work. Dr. Kurosaka received grants and personal fees from Kowa Co., Ltd. and Senju Pharmaceutical Co., Ltd.; personal fees from Hoya Surgical Optics, Inc., Otsuka Pharmaceutical Co., Ltd., and Santen Pharmaceutical Co., Ltd.; and grants from Nippon Ganka Iryocenter Co., Ltd., Novartis Corp., Pfizer, Inc., and Wakamoto Pharmaceutical Co., Ltd., outside the submitted work. Dr. K. Miyata received grants and personal fees from Hoya Surgical Optics, Inc., Otsuka Pharmaceutical Co., Ltd., Santen Pharmaceutical Co., Ltd., Senju Pharmaceutical Co., Ltd., and Wakamoto Pharmaceutical Co., Ltd.; grants from Becton Dickinson & Co., GlaxoSmithKline, Kissei Pharmaceutical Co., Ltd., Novartis Corp., Shionogi, Inc., and Sucampo Pharma, LLC; and personal fees from MSD, Pfizer, Inc., and STAAR Surgical Co. outside the submitted work. Dr. Oshika received grants from Kai Medical, Inc., Novartis Corp., Pfizer, Inc., and Topcon Corp.; personal fees from Japan Focus Co., Ltd., Mitsubishi Tanabe Pharma, and Otsuka Pharmaceutical Co., Ltd.; grants and personal fees from Hoya Surgical Optics, Inc., Kowa Co., Ltd., Santen Pharmaceutical Co., Ltd., and Senju Pharmaceutical Co., Ltd.; and personal fees and nonfinancial support from Tomey Corp. outside the submitted work.
First author: Shinichiro Nakano, MD Division of Ophthalmology, Ryugasaki Saiseikai Hospital, Ibaraki, Japan
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