An international study has concluded that prolonged preoperative use of topical glaucoma medications with preservatives may negatively affect long-term trabeculectomy outcomes.
The research, from the department of ophthalmology at Yeungnam University Hospital in Korea, which was published in Scientific Reports, also said that older age at surgery, higher Glaucoma Medication Intensity Index (GMII) and subsequent cataract surgeries were also risk factors for surgical failure.
The work involved a retrospective study of 201 patients (309 eyes) with primary open-angle glaucoma who underwent trabeculectomy between 1999 and 2014.
The researchers in Korea assessed the association between preoperative topical glaucoma medication with preservatives and long-term outcomes, and worked out a GMII to quantify use of these medications and impacts on success rates after surgery.
Results showed cumulative success rates for all patients were 89.3% at 1 year, 70.6% at 5 years, 59.2% at 10 years and 46% at 20 years.
Trabeculectomy is typically performed in patients who were already treated with multiple glaucoma medications for extended periods, said researcher Dr Somi Lee.
Dr Lee and her colleagues found that “the effect of long-term preoperative medication use on surgical outcomes is crucial”.
“By specifically measuring exposure to topical glaucoma medications using the GMII, we established it as a significant risk factor for trabeculectomy failure.
“Moreover, the prolonged use of multiple topical glaucoma medications may induce chronic conjunctival alterations that adversely affect bleb formation and function.”
She said the findings also suggested that optimising the timing of surgery to avoid prolonged exposure to glaucoma medications, as indicated by the GMII, could improve long-term surgical outcomes.
The study also revealed that age at the time of surgery was a significant factor associated with trabeculectomy failure.
“In our study, patients aged under 40 years with a diagnosis of JOAG had better surgical outcomes and long-term success rates after trabeculectomy.”
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