Lifestyle and Glaucoma: Thinking Earlier, Acting Broader

Glaucoma remains one of the most challenging causes of irreversible vision loss, not because effective treatments are lacking, but because the disease is typically silent until damage is well established. As populations age and patients live longer with early disease, the opportunity and responsibility to intervene earlier has never been greater. The emphasis in glaucoma care is therefore shifting from late intervention to earlier identification of risk and more thoughtful prevention. This does not imply eliminating glaucoma entirely, but rather delaying progression and preserving meaningful vision over a patient’s lifetime.

At its core, glaucoma is a chronic optic neuropathy characterised by retinal ganglion cell loss. Age, genetics, and intraocular pressure (IOP) remain the dominant determinants of risk, yet it has long been clear that IOP alone does not tell the whole story. Many individuals with elevated IOP never develop glaucoma, while others progress despite pressures within the statistically normal range. Prevention, therefore, requires a broader view that integrates risk stratification, lifestyle considerations, and early structural detection.

Lowering IOP remains the only proven disease-modifying strategy. The Ocular Hypertension Treatment Study confirmed that early treatment reduces the risk of conversion to glaucoma in selected patients, particularly when factors such as thinner central corneal thickness and optic nerve vulnerability are present. In practice, this supports a more individualised approach: not every patient with ocular hypertension requires treatment, but those at higher risk benefit from earlier intervention.

Topical therapy remains effective, though adherence is often imperfect in an asymptomatic disease. Increasingly, selective laser trabeculoplasty (SLT) is being used earlier, offering durable pressure reduction without the burden of daily drops and without relying on long-term adherence in patients who feel entirely well. For preventive care, this shift reflects both emerging evidence and pragmatism.

Beyond IOP, several lifestyle and systemic factors appear to influence risk and progression, particularly in susceptible individuals. Regular aerobic exercise has been associated with modest reductions in IOP and improved vascular health. Smoking cessation and management of systemic cardiovascular risk factors are sensible, particularly given the role of vascular dysregulation in some forms of glaucoma, including normal-tension disease.

Diet has also attracted attention. Observational studies suggest that diets rich in leafy green vegetables, antioxidants, and omega-3 fatty acids are associated with lower glaucoma risk. While causality cannot be assumed, such dietary patterns align with broader health advice and carry little downside.

Vitamin B3 (nicotinamide) has emerged as an area of interest. Experimental work demonstrates improved mitochondrial resilience and retinal ganglion cell survival, and early human data are encouraging. However, large-scale clinical trials are still evolving. At present, nicotinamide should be viewed as a promising adjunct rather than established preventive therapy, and clinicians should be cautious not to overstate its role or substitute it for proven IOP-lowering strategies.

Patients frequently ask about marijuana. While cannabinoids can transiently reduce IOP, the effect is short-lived, inconsistent, and impractical, requiring frequent dosing with systemic and psychoactive side effects. Current evidence does not support marijuana as a safe or effective strategy for glaucoma prevention or treatment.

Other lifestyle considerations are increasingly recognised. Sleep quality and nocturnal physiology may be relevant, particularly in progressive or normal-tension glaucoma. Nocturnal IOP elevation, side-sleeping with the affected eye dependent, and untreated obstructive sleep apnoea have all been associated with disease progression. Systemic blood pressure also requires balance, as both hypertension and excessive nocturnal hypotension may compromise optic nerve perfusion.

Certain physical activities warrant discussion in advanced disease. Sustained inverted yoga positions, heavy breath-holding, and repeated Valsalva manoeuvres can cause significant transient IOP elevations. Advising moderation rather than avoidance is usually appropriate. Rapid ingestion of large fluid volumes may also cause short-term pressure spikes, and simple advice to spread fluid intake can be helpful in susceptible individuals.

Early detection remains central to prevention. Visual field-testing is essential, but structural damage often precedes functional loss. Optical coherence tomography (OCT) has therefore become fundamental in contemporary glaucoma care. Increasing emphasis is being placed on macular ganglion cell analysis, where damage may be detected earlier and more reproducibly than visual field change. Longitudinal OCT monitoring, particularly of the ganglion cell layer, allows progression to be identified at a stage when intervention is most effective, often before functional loss becomes apparent to the patient.

Glaucoma prevention is no longer defined by a single pressure reading or a reactive treatment model. It requires thoughtful risk stratification, attention to systemic and lifestyle factors, and intelligent use of modern imaging. By identifying vulnerability earlier and intervening appropriately, clinicians can meaningfully reduce the long-term burden of glaucoma and preserve vision across a lifetime rather than responding only once damage is done.

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Justin Sherwin, MBBS, PhD FRANZCO is the Director of Peninsula Eye Centre, Vice-President of the Australian Society of Ophthalmologists (ASO), and an Honorary Consultant Ophthalmologist at Vision Australia. He specialises in cataract, refractive and glaucoma surgery and contributes to advisory boards and clinical research.