New Zealand Glaucoma Study Reveals Growth, Stark Equity Gap

A decade-long analysis of New Zealand's national pharmacy dispensing records has laid bare a growing burden of glaucoma treatment alongside deep and persistent inequities in who receives it — findings that eyecare professionals on both sides of the Tasman will want to take note of.

The study, published in the Asia-Pacific Journal of Ophthalmology, is billed as the most comprehensive analysis to date of glaucoma medication dispensing in Aotearoa New Zealand. Researchers from Te Whatu Ora Health New Zealand and the University of Auckland examined more than three million publicly funded glaucoma prescriptions dispensed between 2012 and 2021, drawing on de-identified data from the Ministry of Health.

A growing treatment burden

The numbers point to a steadily rising demand for glaucoma care. The number of unique patients receiving treatment climbed from 39,725 in 2012 to 50,048 in 2021, a 25.9 per cent increase that outpaced New Zealand's population growth over the same period. Treated prevalence of glaucoma or ocular hypertension rose from 0.90 per cent to 0.98 per cent of the population, while the annual incidence of newly treated patients was estimated at 125 per 100,000 people.

Unsurprisingly, age was the dominant driver. Over three-quarters of treated individuals were 65 or older, and almost 80 per cent of all dispensed medications went to people aged 60 to 89, a pattern the authors say reflects New Zealand's ageing population and one likely to intensify as the number of over-65s climbs toward an estimated 1.3 million by 2040.

Latanoprost cements its place as first-line therapy

Prescribing patterns confirmed what many clinicians will already suspect anecdotally: prostaglandin analogues, and latanoprost in particular, now dominate glaucoma pharmacotherapy. Latanoprost accounted for 40 per cent of all glaucoma prescriptions dispensed, well ahead of timolol (13 per cent) and bimatoprost (11 per cent). The authors note this represents a clear shift from earlier New Zealand prescribing data, where beta-blockers held the leading position, a change they attribute largely to the removal of earlier funding restrictions on prostaglandin analogues.

A troubling equity gap

The study's most significant finding, however, is the scale of ethnic disparity in access to treatment. Although Europeans make up 67.8 per cent of the New Zealand population, they received 87 per cent of all glaucoma prescriptions dispensed, with an age-adjusted prescribing rate of 34.7 per 1,000. By contrast, Māori, who represent 17.8 per cent of the population, received just 1.9 per cent of prescriptions, at a rate of 8.5 per 1,000. Pasifika peoples, 8.9 per cent of the population, received 1.4 per cent of prescriptions, at a rate of 14.5 per 1,000. The differences were statistically significant (p<0.001) even after adjusting for age.

The authors are careful to note that a genuine difference in underlying disease prevalence between ethnic groups cannot be ruled out, given the absence of population-based glaucoma prevalence data specific to Māori or Pasifika. But they argue the gap is far more likely to reflect the same systemic barriers documented elsewhere in New Zealand's health system, pointing to comparable inequities in diabetes and cardiovascular disease outcomes among Māori and Pasifika populations. Unequal access to healthcare and specialist services, cultural and communication barriers, potential implicit bias, and a modest gap in life expectancy were all flagged as plausible contributing factors, though the authors stress none fully explains the scale of the disparity.

COVID-19's lingering shadow

The data also captured a sharp spike in dispensing in 2020, consistent with pandemic-related stockpiling reported elsewhere in New Zealand's health system. Notably, while overall dispensing rebounded for European and "Other" patients, it failed to recover to the same extent for Māori, Pacific and Asian patients raising concerns that the pandemic may have widened pre-existing access gaps rather than merely disrupting care temporarily.

Relevance for Australian practice

For Australian optometrists and ophthalmologists, the findings offer a useful comparison point. The authors note general concordance with Australian prevalence estimates, albeit with methodological caveats, the Australian National Eye Health Survey used random-cluster sampling with clinical grading, versus this study's reliance on real-world dispensing data alone. That distinction is itself a point of interest: the New Zealand authors argue dispensing records offer a more accurate picture of actual medication uptake and adherence than prescribing data, since not every prescription written is filled.

The study's authors are calling for further research to unpick the specific mechanisms behind the Māori and Pasifika treatment gap, including funding policy, out-of-pocket costs and referral pathways, and for future work to incorporate surgical and MIGS uptake data to build a fuller picture of glaucoma management intensity across the population.