Glaucoma New Zealand’s (GNZ) recent public campaign highlighted the “injustice” of the lack of alternative, preservative-free (PF), glaucoma drops in New Zealand. Now, in a bid to bolster the evidence behind these concerns, GNZ chair and glaucoma specialist, Professor Helen Danesh-Meyer is running a clinical trial to investigate the ocular impacts of the eyedrop preservative benzalkonium chloride (BAK).

After GNZ used Glaucoma Awareness Week to raise awareness of the dearth of alternative PF glaucoma drops with its members, “we received a barrage of sad stories of how their lives had been impacted”, said Pippa Martin, GNZ general manager. Some of these stories were shared in GNZ’s Eyelights magazine, including one from a woman whose father’s quality of life had been severely diminished by BAK-preserved eyedrops. “Every drop Dad was on to reduce the pressure damaged the cornea, which then meant it really hurt him to open and close (his eye). It damaged the surface of his eye so much that they thought he had this immunosuppressant condition,” she said. He was switched to an oral medication to reduce his intraocular pressure (IOP) and, although the tablet was “incredible” at controlling his IOP, her father was rendered almost helpless, she said. “He was unsteady on his feet. He would sleep all day. Some days he struggled to dress himself… I just don’t understand why if preservative damages the eye so much, we don’t just make the preservative-free ones available?”

GNZ's Pippa Martin and chair Prof Helen Danesh-Meyer

While BAK in eyedrops effectively prevents microbial contamination, accumulating evidence suggests its association with adverse effects on the ocular surface, reported Prof Danesh-Meyer in the background information for the study. “The delicate balance of the tear film, essential for maintaining ocular health, may be disrupted by the chronic exposure to BAK, leading to ocular surface disease, dry eye syndrome and inflammation.” While there are some PF glaucoma drops now available in New Zealand, they are not publicly funded by Pharmac. The new study aims to bridge the gap in the literature specifically about BAK’s effects on the ocular surface, said Prof Danesh-Meyer. The case-control clinical trial will focus on the comparison of inflammatory markers in patients using BAK-containing glaucoma medications (Latanoprost and Dorzolamide) and their PF counterparts (Monoprost and AFT Pharmaceuticals’ Vizo-PF Dorzolatim).

GNZ intends to stay on this crusade and use Prof Danesh-Meyer’s research, its patients’ stories and it’s influential membership to influence Pharmac, said Martin. “I appreciate it will take years. However, we believe stories of Kiwis losing their sight unnecessarily and the impact on them and those around them, in addition to the associated personal and New Zealand health financial burden, are stories we can keep telling.”