Micropulse transscleral cyclophotocoagulation is a laser-based treatment for glaucoma that aims to reduce intraocular pressure while minimizing damage to surrounding ocular structures that function as key components of aqueous humor regulation. A recent study evaluated the 5-year effectiveness and safety of the procedure in patients with primary and secondary glaucoma.
The investigators described the need for such treatments in glaucoma care in their Ophthalmology and Therapy article, where they noted, “Conventional treatments include incisional glaucoma surgery, minimally invasive techniques, or glaucoma tube implantation. For patients with refractory or uncontrolled glaucoma, cyclodestructive procedures like cyclocryocoagulation, cyclodiathermy, or transscleral cyclophotocoagulation (TSCPC) may be considered as a last resort. However, these procedures have been associated with significant complications, including persistent hypotony, inflammation, and vision loss, leading many practitioners to reserve them for cases where other options have failed.”
The retrospective study included 165 eyes treated at the University Eye Clinic Maastricht between 2016 and 2019. Patients had mild to advanced glaucoma and underwent micropulse transscleral cyclophotocoagulation (MP-TSCPC) using a standardized protocol. The initial treatment for intraocular pressure (IOP) less than 30 mmHg was delivered at 2,000 mW for 80 seconds per hemisphere or 90 seconds per hemisphere for patients with IOP greater than 30 mmHg. The power was increased to 2,100 mW for second treatments, and 2,200 mW for third treatments.
Outcomes were assessed at 1 day, 1 week, 1 month, 3 months, 6 months, 12 months, and yearly for 5 years, and focused on IOP reduction, medication usage, and complications such as “corneal pathology, anterior chamber reaction, cystoid macular edema, choroidal detachment, or other ocular abnormalities,” the researchers wrote.
“Partial treatment success was defined as a postoperative IOP reduction of ≥20% compared with baseline or a decrease in the number of IOP-lowering medications with stable IOP,” Ronald M. P. C. de Crom, of the University Eye Clinic Maastricht at the Maastricht University Medical Center, and colleagues wrote. “Total treatment success was defined as both a postoperative IOP between 6 and 21 mmHg and a postoperative IOP reduction of ≥20% compared with baseline and/or a decrease in the number of IOP-lowering medications with stable IOP.”
In the primary glaucoma group (108 patients), mean preoperative IOP was 20.7 ± 7.1 mmHg and mean preoperative medication use was 3.3 ± 1.3 medications. Mean postoperative IOP after 5 years measured 12.9 ± 4.3 mmHg and mean medication use decreased to 2.7 ± 1.3 medications. The investigators broke down the number of patients who achieved treatment success after each year. After 1 year, 64.8% of patients achieved success. This percentage increased to approximately 75% over years 2 and 3, but decreased back to 66.7% over years 4 and 5.
In the secondary glaucoma group of 57 patients, mean preoperative IOP measured 28.7 ± 10.3 mmHg with a mean of 3.5 ± 1.2 medications used. Mean postoperative IOP after 5 years measured 15.5 ± 7.6 mmHg with a mean of 2.5 ± 1.7 medications used. Treatment success was also measured after each year in this group. After 1 year, 64.9% of patients achieved treatment success. This percentage rose to 77.8% in year 2, decreased in year 3, and increased again over years 4 and 5, where it ended at 80.0% treatment success.
Among the complications were 3 cases of cystoid macular edema, 2 cases of corneal graft rejection, and 1 case of fibrinous anterior chamber reaction, all of which were reversible with prolonged topical steroid treatment. One patient experienced persistent hypotony with an IOP of 3 mmHg, but had no signs of hypotony maculopathy.
While retreatment was needed in 40.6% of eyes initially, the retreatment rate decreased to 30.9% after 1 year. The researchers reported no statistically significant differences in pretreatment need between patients with primary or secondary glaucoma, nor any statistically significant correlations between the number of preoperative medications and the need for additional surgery.
“Visual acuity (VA) decreased by more than two lines on the Snellen chart in 34.9% of patients after 1 year,” the researchers wrote. “Most VA losses were related to retinal disease, cataract, or glaucoma progression. At 1 year, 8 patients experienced unexplained vision loss, which may have been due to variations in VA measurements or decreased CDVA due to (natural) glaucoma progression.”
Limitations included significant loss to follow-up and lack of diversity with a predominantly white population.
Still, the investigators concluded, “micropulse TSCPC is a safe and effective treatment for lowering IOP and decreasing the number of IOP-lowering medications. Micropulse TSCPC can also be considered a good alternative treatment option for patients after failed incisional glaucoma surgery or patients who are at high risk for incisional surgery.”
A full list of author disclosures can be found in the published research.