Skip to main content
Download PDF

Quantitative visual tests in primary open-angle glaucoma patients according to three different lights with different color-rendering index

BMC Ophthalmology volume 21, Article number: 238 (2021) Cite this article

Abstract

Purpose

To compare quantitative visual tests, such as visual acuity, contrast sensitivity, and color vision tests in patients with primary open-angle glaucoma (POAG) patients according to three different light systems with different color-rendering index (CRI).

Methods

This was a cross-sectional study of 36 eyes in 36 patients with POAG. Three different light systems consisting of a 3-band fluorescent lamp (CRI 80), a white LED (CRI 75), and a quantum dot LED (CRI > 95) were used. All lights had the same illuminance of 230 lx to exclude illuminance effects. The visual testing included best-corrected visual acuity (BCVA) using an ETDRS chart, a CSV-1000E contrast test, and a color test performed by the Farnsworth Munsell 100-hue test.

Results

There was no significant difference in BCVA (p = 0.86). There were no significant differences in the detail contrast tests according to the three light systems (p = 0.95, p = 0.94, p = 0.94, respectively, p = 0.64). There was significant difference between the three light systems in color test (p = 0.042). The color test scores with a quantum dot LED were significantly lower than those of the white LED and 3-band fluorescent lamp (p = 0.03 and 0.047, respectively).

Conclusions

POAG patients did not show significant differences in visual acuity scores and contrast test scores, expressed as black and white symbols, according to the different light systems. However, POAG patients tested under a quantum dot LED (CRI > 95) could distinguish color differences better than in the other light systems.

Peer Review reports

Introduction

Glaucoma is a chronic, progressive heterogeneous group of diseases characterized by cupping of the optic nerve head and irreversible visual impairment. [1] It has become the most frequent cause of irreversible blindness worldwide[2, 3]. Patients with glaucoma may suffer from the inconvenience of using anti-glaucoma drugs, economic concerns for the cost of anti-glaucoma treatment, and obstacles faced with the visual impairment of glaucoma. Also, glaucoma impacts individuals in several ways, including a reduced ability to perform self-care activities[4], decreased steroacuity[5], being prone to traffic accidents,[6] depression,[7] and falls[8]. Thus, the quality of life (QoL) is strongly influenced by glaucoma. Specifically, impairment in visual acuity, contrast acuity, and color discrimination due to glaucoma negatively impacts physical and mental health and is a global concern.

Visual function also may be affected by artificial light sources because artificial light is common in the daily life of most people who consume around 2650 billion MWh/year, almost 19 % of the worldwide electricity production.[9] Traditionally, incandescent lights have been used as artificial light sources. However, as of the first of September 2016, no more incandescent lights were available in Europe for domestic lighting due to environmental problems and solid-state lighting based on light-emitting diodes (LEDs) has become the next-generation light source. Compared to conventional general illumination solutions, such as incandescent bulbs and compact fluorescent lamps, white LEDs have several advantages, including high luminous efficacy (> 70 lm W− 1), long lifetime (> 25,000 h), dimmability, and fast response times. [10] Moreover, several values are used to measure and judge the performance and color quality of artificial light sources, including LEDs. These are the color-rendering index (CRI), the correlated color temperature (CCT), and visual energy efficiency (luminous efficacy of radiation, LER), among others.[11, 12].

Thus, the purpose of this study was to evaluate three different kinds of light systems affect on quantitative visual tests in glaucoma patients and determine if the visual function in glaucoma patients was affected by the CRI degree used in the typical and traditional color quality metrics of artificial light systems.

Methods

Subjects

This study adhered to the tenets of the Declaration of Helsinki and Ulsan University Hospital Institutional Review Board approval was obtained (UUH 2021-01-010). We obtained informed consents from all subjects. The study was a cross-sectional study and all subjects were enrolled between June 2017 and May 2019.

The subjects in the POAG group were recruited from the Department of Ophthalmology at Ulsan University Hospital, South Korea. The inclusion criteria for the POAG group were (1) a cup-to-disc ratio ≥ 0.5 or > 0.2 difference in the cup to disc ratio of each eye, (2) a defect in the retinal nerve fiber layer (consistent with a glaucomatous change in the optic nerve) on either a fundus photograph taken using red-free light or an optical coherence tomography image, (3) evidence of glaucomatous visual field loss using a Humphrey Field Analyzer (with the Swedish Interactive Threshold Algorithm-Standard 30 − 2 or 24 − 2 program), and (4) open angle was assessed by van Herick method first. If anterior chamber depth was shallower than grade 3 (PAC = 1/4 to 1/2CT), gonioscopic examination was used to confirm open angle. All POAG patients were diagnosed by one glaucoma specialist (C.K.L).

The exclusion criteria were as follow: best-corrected visual acuity < 0.1 on a decimal scale or > 1.0 on the logarithm of the minimum angle of resolution scale; the presence of uveitis or other retinal diseases; severe cataract (> 3 nuclear opalescence classified by LOCS III)[13]; myopia of ≥ − 6 D; age > 65 or < 18 and a history of cerebrovascular disease, ocular trauma.

The sample size was calculated by using of our pilot study results. Sample number of pilot was five and within group standard deviation (SD) was 81.2. One-sided alpha level was set as 0.05, the power was 80 %, and dropout rate was 10 %. Finally, the study population of each group was calculated 36.

All quantitative visual tests were performed in our light research lab. All tests were administered to all patients in turn through group 1,2 and 3 order and BCVA test was first performed, followed by CSV and color tests in the same order for all patients. There were three different light systemes in this study; a 3-band fluorescent lamp that had a CRI of 80 was classified as Group 1, a general white LED that had a CRI of 75 and was classified as Group 2, and a quantum dot LED that had a CRI as 95 and was classified as Group 3. The light sources were suspended from the ceiling of our lab. In the white and quantum dot LED, an attenuator was fitted to control the illumination. All quantitative visual tests were conducted after controlling the illuminance from each source at 230 lx by using digital light meter (TES-1330 A, TES, Taiwan) because all visual acuity and contrast test were essentially needed under same illuminance [14] (Fig. 1).

Fig. 1
figure 1

The ETDRS chart and CSV-1000E chart under each of three different light systems. (A)3-band fluorescent lamp (CRI: 80). (B) White LED (CRI: 75). (C) Quantum dot LED (CRI > 95). (D, G) ETDRS and CSV-1000E charts under the 3-band fluorescent lamp. (E, H) ETDRS and CSV-100E charts under the white LED. (F, I) ETDRS and CSV-1000E charts under the quantum dot LED

Full size image

Best-Corrected Visual Acuity (BCVA)

BCVA was checked by ETDRS charts that were used for a test distance range of 3 m. One eye of each patient was tested and the eye to be tested was chosen by tossing a coin. There was a 5-minute break after each test under each light system to rule out fatigue effects and interference from the previous light system. This was commonly done by counting the number of letters read correctly on the entire chart and converting this to an acuity score by means of a simple formula that placed an L or N value on the letter, where L was the difference in acuity between adjacent lines and N was the number of letters per line. Thus, in a chart with five letters per line and a 0.1 LogMAR progression from line to line, each correct letter is worth 0.1/5 = 0.02LogMAR[15].

Contrast Sensitivity Test (CSV)

Contrast sensitivity testing was done with a CSV-1000E (Vector Vision, Dayton, OH, USA)[16] The test distance was 2.5 m and one eye of each patient was tested and the eye to be tested was chosen by tossing a coin. There was a 5-minute break time after each test under each light system to rule out fatigue effects and interference from the previous light system. The CSV-1000E provides for four rows of sine-wave gratings with spatial frequencies of 3, 6, 12, and 18 cycles/degree (CPD). The CSV results are presented as log values according to a table provided by the manufacturer.

Color test

Color testing was done by the Farnsworth-Munsell(F-M) 100 hue test (VeriVide, Enderby, United Kingdom)[17]. This test was the 85 colored- cap version. The caps are arranged in four boxes, each containing a fixed anchor cap at each end. There were 22 caps in box 1 and 21 caps in each of the remaining three boxes. Standard administration procedures were followed whereby, for each tray, the intermediate caps were removed from the tray and placed in a random arrangement while the participant looked away. The participant is then asked to view and place the intermediate caps in the correct order in the tray between the two fixed caps, with as little difference in hue between the neighboring caps as possible. The tray was completed in a different order by each participant. The order in which the participant placed the caps was recorded by the experimenter. The tests were conducted under the same illumination with different light systems and one eye of each patient was tested. There was a 10-minute break after each test under every light system to rule out fatigue effects and interference from the previous light system. Standard scoring procedures were followed. Error scores for each tray position were calculated based on the differences between the chosen cap and the two neighboring caps, generating a baseline score of 2 for each cap when in perfect order. Error scores for caps at the end of each tray were calculated using the neighboring cap in the same tray and the first cap of the next tray so that all caps were considered on a continuum around a color circle. The total error score (TES) was measured and computed, in which a higher number of misplacements is reflected by larger TES values. Also, age-matched normal persons were administered the same procedure for comparing results to the POAG patients.

Statistical analysis

One-way ANOVA were used to analyze the data and a p-value of < 0.05 was considered statistically significant. if values were statistically significant, subsequent post hoc multiple comparison using Duncan revealed specific group difference. All statistical analyses were performed using Statistical Package for the Social Sciences (SPSS) for Windows (version 21.0, SPSS, Inc., Chicago, IL, USA).

Results

Thirty six eyes of 36 POAG patients were included in this study. The age range of the patients was 15 − 64 years (mean age, 46.7 ± 14.2 years). The ratio between men and women was 61.1/38.9 %. The MD of visual field test in this group was − 10.5 ± 9.0 decibels (dB)(range, -2.00 to -26.78 dB) and the mean PSD in this group was 7.24 ± 4.7 dB (range, 1.75 to 15.08 dB) (Table 1).

Table 1 Baseline characteristics of the patients (20 eyes of 20 patients)
Full size table

There was no significant difference in BCVAs in the three groups (p = 0.86) (Table 2). There was no significant difference in the detail contrast test (A, B, C, D) in the three groups (p = 0.95, p = 0.94, p = 0.94, p = 0. 64, respectively) (Table 3).

Table 2 BCVA values between the three groups by ETDRS (LogMAR)
Full size table
Table 3 Contrast test Values between the three groups by CSV-1000E (Log value)
Full size table

The mean TES was significantly difference in between groups (p = 0.042)(Table 4) and the quantum dot LED group had significantly lower TES than other groups (Table 4; Fig. 2) Also, there were no significant differences of the TES according to three different light systems between non-glaucoma subjects age-matched to the study subjects (p > 0.05) (Fig. 2). The mean deviation, which is one of the Humphrey visual field indices, was significantly negatively correlated with the TES of the color test (p = 0.001)(Fig. 3A) and the pattern standard deviation, which is another Humphrey visual field index, was significantly positively correlated with the TES of color testing (p = 0.002)(Fig. 3B).

Table 4 Color test values between the three groups by the F-M 100 hue test.
Full size table
Fig. 2
figure 2

Relationship between color tests and groups (light systems). Black bar shows results of glaucoma patients and gray bar shows result of normal subjects that were age-matched to glaucoma patients. There were significant differences between group 1 and group 3, and group 2 and 3 in the TES of the color test in glaucoma patients(asterisk means significant difference) (p = 0.047, p = 0.03, respectively).There was no significant difference between groups in normal subjects. There was no significant difference between group 1 and group 2 (p > 0.05). Group 1: 3-band fluorescent lamp (CRI: 80), Group 2: White LED (CRI: 75), Group 3: Quantum dot LED (CRI > 95)

Full size image
Fig. 3
figure 3

Relationship between the color test, MD, and PSD. (A)There was a significant negative relationship between the MD and TES of the color test (r = -0.549, p = 0.001). (B) There was a significant positive relationship between the PSD and TES of the color test (r = 0.385, p = 0.002)

Full size image

Discussion

This study showed that there was no difference in the ability of glaucoma patients to distinguish items in the visual acuity and contrast tests under different lighting systems, although the glaucoma patients, especially the POAG patients, had trouble distinguishing color depending on the quality of light in the different light systems. Also, according to our previous study, there was no difference in the ability of normal subjects to distinguish color under the same light system used to in this study[13]. The results of this study indicated that glaucoma patients had no difficulty distinguishing black and white under different types of light sources or different light quality if the different light systems had the same illuminance. However, the ability of glaucoma patients to distinguish color was significantly different according to the CRI. The CRI is one of the major and traditional performance metrics and constant values used to judge color quality and is well known as a color metric used to reproduce good saturated colors of illuminated objects under white conditions[12]. A good white light source must render the real colors of the objects it illuminates. This feature of light sources has great importance for indoor lighting applications. Moreover, under low ambient lighting, such as outdoor lighting, Reynham et al. indicated that good color rendition helped to increase road safety by improving color contrast.[18]The CRI was developed by the Commission Internationale de l’Eclairage (CIE) in 1971[19]and updated to its current form in 1995[20]. The best CRI value is 100, whereas the worst is -100.[11] Accordingly, a light system with a high CRI indicates that the light source illuminates the object’s true color perfectly and provides the capability for accurate color discrimination. Therefore, we presumed that glaucoma patients might have some trouble with color discrimination under light systems with low CRI scores and easily distinguish color under a light system with a high CRI, independent of the type of light system if the illuminance was the same. This finding is very important for glaucoma patients because it is strongly associated with vision-related QoL in glaucoma patients. Many previous studies have reported that the QoL of glaucoma patients was lower than normal individuals because visual impairment significantly affects QoL. [21,22,23] Color discrimination is a type of visual function, such as visual acuity and the contrast test. Therefore, low color discrimination could affect QoL in glaucoma patients. It is well known that acquired color vision defects occur in glaucoma [24,25,26,27]because defects in the photoreceptors and optic nerve fibers distort color perception[28, 29] and the color vision defect may become worse when the glaucomatous visual defect is more severe. [21, 27] Thus, in this study, glaucoma patients with acquired color vision defects could have more difficulty distinguishing color influenced by the quality of the light system, as indicated by factors such as the CRI rather than the type of light system and this will be more severe in patients with more severe glaucoma (Fig. 3). The reason the CRI differs according to the light source is that an incandescent lamp has a continuous spectrum and a fluorescent lamp has a discrete line spectrum. An incandescent lamp has a higher CRI, however, incandescent lamps have surpassed them in terms of energy efficiency.[11] White LEDs usually have a low CRI (< 70) and a high correlated-color temperature (CCT > 6000 K)[30], which is another typical and classic performance metric and negatively correlated with the CRI. In contrast, quantum dot LEDs have other advantages. They exhibit fine spectral tuning, achieved by their size control and narrow-band emission[31]. Therefore, with optimized spectral designs, the real color of objects can be rendered properly while achieving a warm white shade and good spectral overlap with the sensitivity of the human eye.[11] Moreover, quantum dot LEDs with a high color CRI are graded as third-generation LED lights by LED-related scientists and engineers[12].

Moreover, many glaucoma patients use multiple antiglaucoma drugs and when they use these drugs, the bottle cap color is the most commonly used method for identifying the glaucoma medications.[32] Therefore, if glaucoma patients with acquired color vision defects have trouble in a low-CRI light system, they may confuse other drugs with anti-glaucoma drugs and lead to low adherence with glaucoma treatment and low treatment efficacy.

One of the limitations of this study was that the ETDRS and CSV-1000E tests were recommended to use retro-illumination as the illumination source rather than projection or using direct illumination because projection or direct illumination have a lack of sufficient luminance and contrast. However, in our study, the light systems were hung from the ceiling of our lab and we could only use direct illumination for the tests. However, the most important factor during all the tests was illuminance and we checked in front of the test chart and the F-M color unit and then controlled the attenuation of the two LEDs to match the illuminance of the 3-band fluorescent lamp (230 lx).

Also, the effect of the color metric degree on glaucoma target tissues and target cells, such as optic disc and retinal ganglion cells, must be evaluated by in vitro and in vivo tests in detail and step by step. Because, high-quality light systems, such as those with a high CRI, help glaucoma patients improve color discrimination though, light could be a risk factor in glaucoma or be a protector to glaucoma according to light character. [33,34,35].

In conclusion, glaucoma patients with deficiencies in color discrimination could be affected, not by the type of light system with the same illumination, but the quality of the light system, especially the CRI. Patients with more severe visual field defects had a lower ability to discriminate color. Thus, a more high-quality light system could increase the ability of color distinction and may increase the QoL in glaucoma patients because the relationship between ability of color distinction and QoL has been closed. In future studies, the safety of the main target organ or cells in glaucoma affected by different light systems and quality should be investigated according to several light quality indices, such as the CRI and CCT, by in vivo and in vitro testing.

Availability of data and materials

The datasets used and analysed during the current study are available from the corresponding author on reasonable request.

References

  1. Jonas JB, Aung T, Bourne RR, et al. Glaucoma. Lancet. 2017;390:2183–2193.

  2. Bourne RR, Taylor HR, Flaxman SR, et al. Number of People Blind or Visually Impaired by Glaucoma Worldwide and in World Regions 1990–2010: A Meta-Analysis. PLoS One. 2016;11:e0162229.

    Article  Google Scholar 

  3. Tham YC, Li X, Wong TY, et al. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014;121:2081–2090.

    Article  Google Scholar 

  4. Freeman EE, Egleston BL, West SK, et al. Visual acuity change and mortality in older adults. Invest Ophthalmol Vis Sci. 2005;46:4040–4045.

    Article  Google Scholar 

  5. Park CK, Kim DW, Lee CK. Near and Distance Stereoacuity in Patients With Primary Open-angle Glaucoma. J Glaucoma. 2018;27:537–542.

    Article  Google Scholar 

  6. Chia EM, Wang JJ, Rochtchina E, et al. Impact of bilateral visual impairment on health-related quality of life: the Blue Mountains Eye Study. Invest Ophthalmol Vis Sci. 2004;45:71–76.

    Article  Google Scholar 

  7. Jampel HD, Schwartz A, Pollack I, et al. Glaucoma patients’ assessment of their visual function and quality of life. J Glaucoma. 2002;11:154–163.

    Article  Google Scholar 

  8. Haymes SA, Leblanc RP, Nicolela MT, et al. Risk of falls and motor vehicle collisions in glaucoma. Invest Ophthalmol Vis Sci. 2007;48:1149–1155.

    Article  Google Scholar 

  9. Behar-Cohen F, Martinsons C, Vienot F, et al. Light-emitting diodes (LED) for domestic lighting: any risks for the eye? Prog Retin Eye Res. 2011;30:239–257.

    Article  CAS  Google Scholar 

  10. Tu C-C, H. Hoo J, Böhringer K, et al. Red-emitting silicon quantum dot phosphors in warm white LEDs with excellent color rendering. Optics Express. 2014;22:15–17.

  11. Erdem T, Demir Hilmi V. Color science of nanocrystal quantum dots for lighting and displays. Nanophotonics2013. p. 57.

  12. Yoon HC, Oh JH, Lee S, et al. Circadian-tunable Perovskite Quantum Dot-based Down-Converted Multi-Package White LED with a Color Fidelity Index over 90. Sci Rep. 2017;7:2808.

    Article  Google Scholar 

  13. Yo Sep Yoon CKL, Sang Ook Kang, Sang Woo Kim. Comparison of Contrast Sensitivity and Color Vision according to the Different Illumination in Patients with Cataract. J Korean Ophthalmol Soc. 2018;7:622–628.

    Article  Google Scholar 

  14. Sheedy JE, Bailey IL, Raasch TW. Visual acuity and chart luminance. Am J Optom Physiol Opt. 1984;61:595–600.

    Article  CAS  Google Scholar 

  15. Schachat APS, SriniVas R;Hinton, David R; Wilkinson, C.P; Wiedemann, Peter. Ryan’s RETINA. 6th ed. philadelphia, PA: Saunders Elsevier; 2017.

    Google Scholar 

  16. Pomerance GN, Evans DW. Test-retest reliability of the CSV-1000 contrast test and its relationship to glaucoma therapy. Invest Ophthalmol Vis Sci. 1994;35:3357–3361.

    CAS  PubMed  Google Scholar 

  17. Farnsworth D. The Farnsworth-Munsell 100-hue test for the examination of color discrimination. Baltimore, Md.: Munsell Color Company. Inc; 1957.

  18. Raynham P, Saksvikronning T. White light and facial recognition. Raynham, P. and Saksvikronning, T. (2003) White light and facial recognition. The Lighting Journal, 68 (1). pp. 29–33. ISSN 02650398. 2003;68.

  19. Robertson AR. Colorimetry. Reports on Progress in Physics. 1978;41:469–510.

    Article  CAS  Google Scholar 

  20. Method of Measuring and Specifying Colour Rendering Properties of Light Sources, CIE Publication 13.3–1995. Color Research & Application. 1995;20:212–212.

  21. Alqudah A, Mansberger SL, Gardiner SK, et al. Vision-related Quality of Life in Glaucoma Suspect or Early Glaucoma Patients. J Glaucoma. 2016;25:629–633.

    Article  Google Scholar 

  22. Gupta V, Srinivasan G, Mei SS, et al. Utility values among glaucoma patients: an impact on the quality of life. Br J Ophthalmol. 2005;89:1241–1244.

    Article  CAS  Google Scholar 

  23. Wu P, Xi S, Xia H, et al. Survey on vision-related quality of life and self-management among patients with glaucoma. J Glaucoma. 2014;23:75–80.

    Article  CAS  Google Scholar 

  24. Drance SM, Lakowski R, Schulzer M, et al. Acquired color vision changes in glaucoma. Use of 100-hue test and Pickford anomaloscope as predictors of glaucomatous field change. Arch Ophthalmol. 1981;99:829–831.

    Article  CAS  Google Scholar 

  25. Flammer J, Drance SM. Correlation between color vision scores and quantitative perimetry in suspected glaucoma. Arch Ophthalmol. 1984;102:38–39.

    Article  CAS  Google Scholar 

  26. Gunduz K, Arden GB, Perry S, et al. Color vision defects in ocular hypertension and glaucoma. Quantification with a computer-driven color television system. Arch Ophthalmol. 1988;106:929–935.

    Article  CAS  Google Scholar 

  27. Niwa Y, Muraki S, Naito F, et al. Evaluation of acquired color vision deficiency in glaucoma using the Rabin cone contrast test. Invest Ophthalmol Vis Sci. 2014;55:6686–6690.

    Article  CAS  Google Scholar 

  28. Adams AJ, Johnson CA, Lewis RA. S cone pathway sensitivity loss in ocular hypertension and early glaucoma has nerve fiber bundle pattern. Colour vision deficiencies X: Springer; 1991. p. 535–542.

    Google Scholar 

  29. Nork TM. Acquired color vision loss and a possible mechanism of ganglion cell death in glaucoma. Trans Am Ophthalmol Soc. 2000;98:331–363.

    CAS  PubMed  PubMed Central  Google Scholar 

  30. Liu S, Sun P, Liu Y, et al. Warm White Light with a High Color-Rendering Index from a Single Gd3Al4GaO12:Ce3 + Transparent Ceramic for High-Power LEDs and LDs. ACS Applied Materials & Interfaces. 2019;11:2130–2139.

    Article  CAS  Google Scholar 

  31. Erdem T, Demir HV. Semiconductor nanocrystals as rare-earth alternatives. Nature Photonics. 2011;5:126.

    Article  CAS  Google Scholar 

  32. Marando CM, Seibold LK, SooHoo JR, et al. The Utility of Cap Color and Bottle Characteristics for Topical Glaucoma Therapy. Ophthalmology. 2015;122:2577–2578.

    Article  Google Scholar 

  33. Del Olmo-Aguado S, Nunez-Alvarez C, Osborne NN. Red light of the visual spectrum attenuates cell death in culture and retinal ganglion cell death in situ. Acta Ophthalmol. 2016;94:e481-491.

    Google Scholar 

  34. Osborne NN, Lascaratos G, Bron AJ, et al. A hypothesis to suggest that light is a risk factor in glaucoma and the mitochondrial optic neuropathies. Br J Ophthalmol. 2006;90:237–241.

    Article  CAS  Google Scholar 

  35. Osborne NN, Nunez-Alvarez C, Del Olmo-Aguado S. The effect of visual blue light on mitochondrial function associated with retinal ganglions cells. Exp Eye Res. 2014;128:8–14.

    Article  CAS  Google Scholar 

Download references

Acknowledgements

Not applicable.

Funding

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT(NRF-2017R1C1B5018279) and supported by a 2018 Ulsan University Hospital Research Grant (UUH-2018-13).

Author information

Authors and Affiliations

  1. Department of Ophthalmology, Ulsan University Hospital, University of Ulsan College of Medicine, 877 Bangeojinsunhwando-ro, Dong-gu, 44033, Ulsan, South Korea

    Sang Woo Kim & Chang Kyu Lee

  2. GL Vision Co., Ltd, Seo-myeon, Republic of Korea

    YoungWook Go

  3. Department of Advanced Materials Chemistry, Korea University, Seoul, South Korea

    Sang-Ook Kang

  4. Biomedical Research Center, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea

    Chang Kyu Lee

Authors
  1. Sang Woo Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. YoungWook Go
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sang-Ook Kang
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Chang Kyu Lee
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

SWK ,SOK and CKL had the substantial contributions to the conception and designed of the work. SWK and CKL collected and analysed the data. YWG provided study material. SOK and YWG interpreted of data. SWK and CKLdrafted the work and all authors substantively revised it.

Corresponding author

Correspondence to Chang Kyu Lee.

Ethics declarations

Ethics approval and consent to participate

This study adhered to the tenets of the Declaration of Helsinki and Ulsan University Hospital Institutional Review Board approval was obtained (UUH 2021-01-010). We obtained informed consents from all subjects.

Consent for publication

Not applicable.

Competing interest

The authors declare that they have no competing interests.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Kim, S.W., Go, Y., Kang, SO. et al. Quantitative visual tests in primary open-angle glaucoma patients according to three different lights with different color-rendering index. BMC Ophthalmol 21, 238 (2021). https://doi.org/10.1186/s12886-021-02005-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1186/s12886-021-02005-2

Keywords

BMC Ophthalmology

ISSN: 1471-2415

Contact us