GLANCE

Glaucoma is a progressive eye disease that leads to irreversible damage to the optic nerve, primarily affecting the retinal ganglion cells, which transmit visual information from the eye to the brain. As these cells deteriorate,
patients gradually lose peripheral vision, which can progress to tunnel vision and eventually blindness. Currently,
glaucoma affects an estimated 76 million people globally (Tham et al., 2014), making it one of the leading causes of irreversible blindness. In the Netherlands, its prevalence is around 3.5% (Springelkamp et al., 2017).
While standard clinical tests like visual field assessments and intraocular pressure measurements are effective at
identifying structural damage, they do not fully capture the functional vision challenges that glaucoma patients
face in daily life. Many patients report difficulties seeing in dimly lit environments, which are often not reflected in clinical assessments (Biering et al., 2018). Additionally, glaucoma patients suffer from increased visual crowding, which is the difficulty in recognizing objects when surrounded by other objects (Tanriverdi et al., 2024; Shamsi et al., 2022, Ogata et al., 2019).
These two issues—difficulty in low lighting and elevated crowding—are not sufficiently accounted for in current
diagnostic practices, leading to a gap in understanding how glaucoma affects patients’ real-world vision. In the
GLANCE project we aim to investigate the relationship between increased crowding in glaucoma and patients'
difficulties with visual tasks under low-light conditions.

The objective of the GLANCE project is to test the hypothesis that visual crowding in individuals with glaucoma is
selectively raised under low-luminance conditions.
If this hypothesis is supported, this would contribute to our understanding of the challenges glaucoma patients
face during everyday tasks such as reading and navigating dimly lit environments. The findings could lead to the
development of specific clinical tests that better capture functional vision and guide targeted rehabilitation
strategies. These advancements could also improve the monitoring of disease progression and treatment
effectiveness, ultimately enhancing patients' quality of life.

This study will employ a prospective cross-sectional design and will span 12 months to allow for sufficient data
collection and analysis. Visual crowding assessments will be conducted under photopic(200 cd/m2), mesopic(2 cd/ m2), and scotopic luminance (0.02) levels. We will ask glaucoma patients and healthy aged-matched controls to perform a computerized crowding test under three different conditions.  This test was developed within the UMCG by us, in the Department of Ophthalmology (Laboratory of Experimental Ophthalmology), and previously tested on healthy controls in a pilot study prior to this project (RR number: 18019). It does not fall under the Medical Device Regulation, as they are not medical devices. The design of this test can be find in the research protocol.
The crowded conditions and isolated conditions will be presented randomly in one block. The luminance
conditions will be measured in separate blocks. Each participant will complete all luminance blocks. One block will consist of 100 trials. Between different blocks, participants will wait wearing the appropriate luminance filters for dark adaptation.
At the end of the visual crowding test participants will be asked to fill out a questionnaire that aims to identify
visual challenges glaucoma participants face on a daily basis under extreme luminance conditions (Bierings et al., 2018). This questionnaire will help to characterize the control and patient population of our study in terms of
complaints under low luminance.
A 2x2x3 mixed effects ANOVA will be conducted on participants' report errors with the main independent
variables: group (glaucoma vs controls), stimulus(crowded vs isolated), and luminance (photopic, mesopic, and
scotopic).

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The potential risks to participants are minimal and may consist of experiencing mild fatigue or eye strain from the experimental procedure and mild discomfort due to sitting still and wearing goggles. The study involves site visits to UMCG. The experiment requires sitting in a dark room in front of a computer screen, looking at various visual stimuli appearing on the screen, and reacting to them using a mouse. One visit requires approximately three hours, and participants will be given ample opportunity to take breaks between examination and experiment sessions. Participants will be asked to sit still and rest their chin on a chinrest without a break for at most 10 minutes in a row during the experimental sessions. Moreover, they will be required to wear goggles equipped with neutral density filters (NDF) to decrease the luminance of the screen.
Participants will be made aware that they can end participation in the study at any time. If they choose to
participate, they will sign an informed consent form prior to participation. Participants will be given a gift card for participating in the study. Possible travel costs will be reimbursed. Data collection will not start until approval of the the ethical review board has been obtained.