Micropulse transscleral laser therapy for glaucoma: a retrospective study
Keywords:
Glaucoma, Intraocular pressure, Laser therapyAbstract
Objective: To evaluate the safety and efficacy of micropulse transscleral laser therapy (MPTLT) in patients with glaucoma at a tertiary eye center in Hong Kong.
Methods: Medical records of patients who underwent MPTLT at Hong Kong Eye Hospital between 1 August 2020 and 31 July 2021 were retrospectively reviewed. Successful treatment was defined as a postoperative intraocular pressure (IOP) between 6 and 21 mmHg or a 20% reduction in IOP from baseline, without an increase in glaucoma medications (topical or oral) or additional glaucoma interventions.
Results: In total, 205 eyes underwent MPTLT either for the first time (n=100) or retreatment (n=105). The mean preoperative visual acuity was 1.6 LogMAR, and 42 (20.5%) eyes had a baseline visual acuity of light perception or worse. The mean preoperative IOP was 27.7 mmHg. All the patients were on the maximum tolerated medical therapy prior to undergoing MPTLT; the mean number of preoperative topical anti-glaucoma medications was 4.1. The mean energy administered was 116.4 J. The overall success rates were 64.9% at 1 month, 51.7% at 3 months, 42.4% at 6 months, 31.2% at 1 year, and 29.3% at 18 months. Success rates were comparable across all time points for both groups. At 18 months or the last visit before additional intervention, the mean IOP reduced 11.3% to 23.3 mmHg (p<0.001), and approximately 23% of patients had an IOP reduction of at least 20%. The mean number of topical anti-glaucoma medications required decreased 5.3% from 4.1 to 3.9 (p=0.003). The decrease was significant in eyes undergoing first-time MPTLT (p=0.004). The percentage of eyes requiring an oral carbonic anhydrase inhibitor also decreased from 72.2% to 44.9% (p<0.001). Patients who received intermediate-energy MPTLT experienced a greater reduction in the number of topical glaucoma medications and in eyes requiring oral carbonic anhydrase inhibitor (acetazolamide) than patients who received low-energy MPTLT. Of 205 eyes, 124 (60.5%) required a mean of 1.9 additional interventions per eye; the median time to the first additional intervention was 3.0 months. Overall, eight (3.9%) eyes developed complications after MPTLT.
Conclusions: MPTLT is a safe and effective treatment modality for various glaucoma subtypes, reducing IOP and the need for topical and oral anti-glaucoma medication. The optimal treatment parameters remain to be determined.
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