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Maintaining a good quality of life in glaucoma patients is second to none. By 2050, the number of people with glaucoma worldwide is estimated to be 111.8 million1. Approximately 28-35% of people over 65 years suffer falls each year, causing a significant socio-economic damage.2,3 One important risk factor for falls in the elderly is poor balance mechanism. Thus, this study by De Luna RA et al. attends to an important subject of geriatric health concern.
De Luna RA et al. in their work aimed to relate the effects of glaucomatous visual field loss on balance. They used a state-of-the-art OPAL kinematic system to quantify sway, jerk and visual dependence as measures of balance. The results revealed that with decreasing visual field sensitivity and increasing number of peripheral test points missed, increased sway and jerk was noted with eyes open on foam surface, greater jerk with eyes open on firm surface and increased sway and jerk in feet together position. They also observed that worse visual field sensitivity was significantly associated with lower visual dependence.
Balance was worse in glaucoma patients with greater VF damage
Balance or postural stability in humans is a complex mechanism with three prime elements - visual input, somatosensory input (proprioception) and the vestibular system.4 Ageing is known to have a deleterious effects on balance control affecting all these mechanisms to some extent.5 Elderly people depend more on their visual inputs for balance compared to the younger counterparts due to the declining proprioception, musculoskeletal strength and cognitive function. Visual field damage in such a scenario gives an additional blow to the already decrepit balance mechanism.6 Previous studies have shown that in patients with glaucoma dependence on visual inputs decreases as visual field damage progresses. Pro-prioception becomes the more important in such scenarios. However, when a patient is subjected to conditions like standing on a foam surface, the proprioception inputs decrease, causing evident 'instability' in the 'stability mechanism'.
A limitation of this study as stated by the author is that it is conducted in a defined prefixed milieu, not so similar to the environment at home, on roads or garden outside. A second limitation is that dynamic balance was not assessed. Thirdly, the study did not take into account the level of physical activity and cognitive function of these patients which could have some effect on balance.
As a step forward, studies should be designed which can simulate natural conditions and are able to assess postural instability while climbing the staircase or on a slippery surface. Efforts should be made to translate these results for the benefit of patients. Trials could be designed to see the effect of balance exercise on glaucoma patients in terms of fear of fall, number of falls, moving around independently and psychological impact.