Hind Alzahrani

PhD Candidate

Research Title: Blue-Blocking Lenses: effect on visual and non-visual systems

Supervisors: Dr Maitreyee Roy & Dr Sieu Khuu

Email Address: h.alzahrani@student.unsw.edu.au



This research aimed to investigate the protective effect of “Blue-blocking” lenses (BBLs) and their effect on visual and non-visual responses.

Seven different types of BBLs from six manufacturers and untinted control lenses with three different powers (+2.00 D, −2.00 D and Plano) were evaluated in this research. The whiteness index of BBLs used in this study was calculated using Commission International de l’Eclairage (CIE) Standard Illuminates D65, and CIE 1964 Standard with a 2 Observer. The protective qualities of BBLs and their effect on blue perception, scotopic vision, and circadian rhythm were evaluated based on their spectral transmittance, which was measured with a Cary 5,000 UV–Vis–NIR spectrophotometer. The effect of BBLs photostress recovery times (PSRTs) in 12 participants were evaluated for chromatic and achromatic stimuli presented under low and high contrast luminance conditions. In addition, the potential effect of BBLs on colour contrast sensitivity was investigated using a custom-designed computer program allowed insight into the performance of goal-oriented behaviours by directly measuring the amount of colour required to detect chromatic targets while wearing BBLs in visual search. Also, the effect of BBLs on colour vision in colour deficient individuals was quantified and compared the magnitude of the effect to individuals with normal colour vision. Finally, the melanopic ratio (Rmel) and circadian stimulus (CS) metrics were calculated for BBLs to compare the effectiveness of the different BBLs types for reducing the ipRGC-influenced responses to light and suppressing the amount of melatonin.

All BBLs negatively affected the colour discrimination ability of both colour deficient and colour normal individuals, photostress recovery time, and colour contrast sensitivity in both high and low luminance contrast conditions but was affected more in lower lighting conditions. However, all results show a degree of variability between lens types with the Blu-OLP lens being the most effective in blocking more blue light. Also, all BBLs used in this study allowed artificial light from lamps and digital devices to alter the natural circadian cycle, but they do not interfere with the natural rhythm of the circadian cycle in the case of natural, solar light exposure. 


Hind Alzahrani is a PhD candidate at the School of Optometry and Vision Science, UNSW, Sydney. Her area of research is focusing on the blue light blocking lenses: effect on visual and non-visual system.

She received her Bachelors (2005) in physics at Taif University, Saudi Arabia, and MPhil in Lighting from Queensland University of Technology (QUT) in 2015. She has worked as a lecturer at Taif University for four years. She is the recipient of a scholarship from the Government of Saudi Arabia.


Bachelor of Science (Physics) 2005, Taif University (TU), Taif, Saudi Arabia

Master of Science: Lighting, 2014, QUT ‐ Brisbane, Australia


Journal Articles

  1. Hind Saeed Alzahrani, Sieu K. Khuu, Maitreyee Roy, "Evaluation of the safety of using commercially available blue-blocking lenses under different blue light exposures", Special Issue - ICTIMESH - 2019, 15-22, ijltetorg. https://www.ijltet.org/journal_details.php?id=954&j_id=4866 
  2. Hind S. Alzahrani, Sieu K. Khuu, Maitreyee Roy, Modeling the effect of commercially available blue- blocking lenses on visual and non-visual functions. Clin Exp Optom. 2019;102(4):1-22.
  3. Hind Saeed Alzahrani, Sieu K. Khuu, Adiba Ali, Maitreyee Roy, The effect of blue-blocking lenses on photostress recovery times for low and high contrast chromatic and achromatic stimuli. OPTOMETRY VISION SCI., 2019: p. 745000. (Accepted and in press)
  4. Hind Saeed Alzahrani, Maitreyee Roy, Vanessa Honson, Sieu K. Khuu. "The effect of blue-blocking lenses on colour contrast sensitivity" Clin Exp Optom 2019. (Accepted and in press)


  1. 15th Conference on Optics Within Life Sciences, 25 - 28 November 2018, Rottnest Island, WA.
  2. Oral presentation in the 3rd Saudi Scientific Symposium, themed: “Aligning Research with Job Market Expectations”, on 18th August 2018, University of Sydney, Australia.
  3. ARVO, 29 Apr 2018 02 May 2018 Hawaii, USA.
  4. AAO Annual Meeting, 12-15 October 2019 Orlando, USA.
  5. ICTIMESH 19, Dubai International Conference Dec. 18-21, 2019.


2018       Travel grant to attend and present paper, Rottnest Island, Western Australia

2019       PRSS (Postgraduate Research Support Scheme) scholarship, UNSW