Glaucoma involves progressive, irreversible damage to the optic nerve, and reduction of intraocular pressure (IOP) is the only proven mechanism to treat the disease.¹ Treatment is essential, because untreated glaucoma will cause serious vision loss and blindness. Vision impairment affects quality of life, and bilateral glaucoma has been associated with difficulty functioning in extreme lighting, limitations or cessation of driving, slower walking, bumping into objects, and falls.²

For patients still working or with an otherwise active lifestyle, limitations following surgeries designed to lower IOP can make the procedures undesirable or even impossible. Patients who have had a tube shunt implantation or a trabeculotomy report reduced function in the postoperative period, with tube shunt implantation causing greater morbidity than trabeculectomy.³ Following a trabeculectomy, 65% of participants reported being able to resume work after 1 week, and 67% reported being able to drive 2 weeks after the procedure, while only 29% of participants that received a tube shunt could work after 1 week and 53% could drive after 2 weeks. Following both procedures, patients are commonly advised not to lift or bend for 2 to 3 weeks, due to risk of hyphema.

Patients who undergo minimally invasive glaucoma surgery (MIGS) face fewer comorbidities and limitations than those who have invasive surgery, but anterior-chamber inflammation, hyphema, and corneal edema have been reported to last up to 3 months after the surgeries.⁴ Here too, the risk of hyphema results in a limitation on lifting and bending following surgery. The incision during surgery requires an additional limitation on activities in or near water, such as swimming and fishing, due to risk of infection.

Laser Treatment

Transscleral cyclophotocoagulation (TSCPC) targets the ciliary body to reduce aqueous humor secretion, thereby reducing IOP. When performed with a continuous wave laser, it is a cyclodestructive procedure in which 810-nm light is absorbed by the melanin in the pigmented ciliary epithelium, leading to coagulative necrosis. The procedure is associated with inflammation and vision-threatening complications, and this has resulted in its use largely being limited to patients who are poor candidates for incisional glaucoma surgery or who have poor visual potential.⁵

The more recent approach of micropulse transscleral cyclophotocoagulation (MPTSCPC), or micropulse transscleral laser therapy (TLT), with the Cyclo G6 laser system (Iridex), causes less tissue disruption to the ciliary body than traditional and low-burn TSCPC treatments, because it does not cause thermal necrosis but rather creates a stress response that induces a biologic effect.⁶ Micropulse technology divides the laser beam into microsecond bursts, which are interspersed with longer resting intervals. The “off” periods allow the tissue to cool between pulses and reduce thermal buildup within the tissue targeted by the laser.

Studies have shown micropulse TLT not only to be effective, but also to have a strong safety profile. A retrospective cohort study of 399 micropulse TLT surgeries on 342 eyes of 214 patients revealed no patients demonstrating the persistent inflammation or hypotony, phthisis bulbi, or sympathetic ophthalmia of concern with continuous-wave TSCPC.⁷ The most common adverse events were vision loss (16.3%), IOP spike (9.1%), and cataract (2.7%). Ocular hypertension as well as all severities and types of glaucoma were represented in the study.

A prospective study comparing the safety and efficacy of micropulse TLT and continuous-wave TS-CPC for the treatment of refractory glaucoma in the pediatric age group included 45 eyes of 36 children and found both treatments to be effective in lowering the IOP in children with refractory glaucoma.⁸ The authors reported the rate of complications, pain, and inflammation to be lower with the micropulse mode, with only 1 of the 17 eyes treated with micropulse TLT developing hypotony for 2 weeks postoperatively.

A retrospective study to report safety and efficacy outcomes following micropulse TLT in patients with uncontrolled glaucoma found the procedure to be a safe and generally effective option in the treatment of primary open-angle glaucoma.⁹ Of the 197 eyes from 161 patients included in the study, complications were limited to 4 cases of cystoid macular edema, which resolved with an extended taper of postoperative prednisolone drops. There was no incidence of corneal edema, prolonged hypotony, phthisis bulbi, or mydriasis.

Reducing Limitations After Surgery

The strong safety profile of micropulse TLT, coupled with the lack of incision during the procedure, eliminates the need for limitations on activity following the treatment. For patients such as an accountant who cannot take any time away from work during tax season, a retiree whose passion is fishing, or a child who should return to school, micropulse TLT provides an effective option that does not disrupt lifestyle.

Conclusion

With its low complication rates, micropulse TLT has a safety profile that makes it possible for patients to resume regular activities directly after the procedure. This allows them to undergo the treatment to lower their IOP despite demanding work or personal responsibilities. GP

Analisa Arosemena, MD, is a glaucoma and anterior segment surgeon at Aran Eye Associates in Miami, Florida. She reports consultancy to Iridex.

References

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8. Abdelrahman AM, El Sayed YM. Micropulse versus continuous wave transscleral cyclophotocoagulation in refractory pediatric glaucoma. J Glaucoma. 2018;27(10):900-905. doi:10.1097/IJG.0000000000001053
9. Yelenskiy A, Gillette TB, Arosemena A, et al. Patient outcomes following micropulse transscleral cyclophotocoagulation: intermediate-term results. J Glaucoma. 2018;27(10):920-925. doi:10.1097/IJG.0000000000001023