Eye Movement Abnormalities in Glaucoma Patients: A Review

Abstract

Glaucoma is a common condition that relies on careful clinical assessment to diagnose and determine disease progression. There is growing evidence that glaucoma is associated not only with loss of retinal ganglion cells but also with degeneration of cortical and subcortical brain structures associated with vision and eye movements. The effect of glaucoma pathophysiology on eye movements is not well understood. In this review, we examine the evidence surrounding altered eye movements in glaucoma patients compared to healthy controls, with a focus on quantitative eye tracking studies measuring saccades, fixation, and optokinetic nystagmus in a range of visual tasks. The evidence suggests that glaucoma patients have alterations in several eye movement domains. Patients exhibit longer saccade latencies, which worsen with increasing glaucoma severity. Other saccadic abnormalities include lower saccade amplitude and velocity, and difficulty inhibiting reflexive saccades. Fixation is pathologically altered in glaucoma with reduced stability. Optokinetic nystagmus measures have also been shown to be abnormal. Complex visual tasks (eg reading, driving, and navigating obstacles), integrate these eye movements and result in behavioral adaptations. The review concludes with a summary of the evidence and recommendations for future research in this emerging field.

Assessing REALTER simulator: analysis of ocular movements in simulated low-vision conditions with extended reality technology

“…We assessed the performance and oculomotor behavior of subjects across three different tasks simulating everyday activities ( Section 3.1 ). Data pertaining to subjects’ behavior in simulated low-vision conditions, including eye and head movements, also exhibited similarities with alterations previously investigated in various studies ( Goodwin, 2014 ; Nguyen et al, 2014 ; Verghese et al, 2021 ; McDonald et al, 2022 ) involving individuals affected by low-vision conditions ( Section 3.2 ).…”

“…Similarly, subjects affected by tunnel vision experience alterations in saccadic movements and fixations, with saccades being more numerous, shorter, and slower, and fixations being more unstable compared to healthy-sighted individuals ( McDonald et al, 2022 ). In our study, simulated tunnel vision resulted in a small amount of shorter saccades across all tasks, particularly impacting tasks requiring object recognition, such as water pouring and block insertion.…”

“…Tubular vision presents initially as a blurred effect in the superior or inferior visual field, progressing to tunnel vision characterized by blurred effects, lack of information, and dark gray peripheral scotomas ( Crabb et al, 2013 ; Gupta et al, 2016 ). Fixation instabilities and altered saccades are common in individuals with tubular vision, affecting daily tasks such as reading ( Nguyen et al, 2014 ; McDonald et al, 2022 ).…”

The impact of horizontal eye movements versus intraocular pressure on optic nerve head biomechanics: A tridimensional finite element analysis study

“…Besides that, to the best of our knowledge, eye movements have not been recognized as a glaucoma risk factor in clinical settings [ 21 , 22 ], and even when eye movement alterations have been reported in glaucoma patients [ [23] , [24] , [25] ], this could primarily be the result of visual pathway and cortex damage observed in this disease [ [26] , [27] , [28] , [29] , [30] ], rather than a direct mechanical injury. In this sense, glaucoma could not be mechanically caused by ocular movements.…”

Central Visual Attention in Primary Open-angle Glaucoma

“…The visual system is biased toward salient stimuli that resolve the competition simply based on the bottom-up input before top-down influences can have an effect. Because of loss of information in peripheral vision, 28,29 we hypothesized that the bottom-up weight is decreased in glaucoma (linked with the input signal loss) as compared with a control group. To compensate the visual loss, top-down processing might be more involved in glaucoma, and the visual search will be probably altered with the use of different strategies during an attentional task.…”