Laser goniopuncture can effectively rescue eyes following failed deep sclerotomy, but there are several factors that might contribute to its success or failure, according to research results published in the British Journal of Ophthalmology.
Serious postoperative complications can occur after laser goniopuncture, among them iris incarceration. Although laser goniopuncture is generally safe, researchers sought to report the incidence, long-term outcomes, and prognostic factors associated with laser goniopuncture after deep sclerectomy through a large, retrospective cohort study.
Consecutive patients who underwent laser goniopuncture after deep sclerectomy at 2 institutions in the United Kingdom between 2014 and 2020 were included in the current study. The primary study outcome was the success rate of deep sclerectomy following laser goniopuncture; secondary outcomes included procedure incidence and prevalence, prognostic factors for the outcome after the procedure, intraocular pressure (IOP), best-corrected visual acuity (BCVA), and the number of medications required during follow-up, in addition to the occurrence of complications — specifically, iris incarceration — following laser goniopuncture procedures.
The cohort included 1765 eyes from 1385 eligible patients. Within this group, 1076 and 689 eyes underwent either deep sclerectomy or deep sclerectomy combined with cataract extraction. In total, laser goniopuncture was performed in 53% of eyes (n=942) at a median of 24.3 months after deep sclerectomy (95% CI, 21.7-28.0). Estimated laser goniopuncture incidence was 33.3%, 56.3%, and 62.8% at 1, 3, and 5 years, respectively.
Among the eyes that underwent laser goniopuncture, 42 had no available data following the procedure; a total of 900 eyes were included in the study. Median follow-up after the procedure was 43 months (interquartile range [IQR], 18 to 81 months).
In the follow-up period, mean IOP decreased from 21.2±6.0 mm Hg before the procedure to 14.1±4.8 mm Hg, 13.8±5.2 mm Hg, and 12.9±4.7 mm Hg at each timepoint: 1, 3, and 5 years, respectively. IOP values at all points following the procedure were significantly lower compared with preprocedure values.
Only 39 eyes — 4.3% of patients — were taking glaucoma medications before laser goniopuncture; the number of medications significantly increased in the postprocedure period while remaining as low as less than 0.5 medications per eye.
Postprocedure BCVA did not change significantly until 1-year follow-up; the reduction was then mild, which was statistically — but not clinically — significant.
The researchers conducted multivariable Cox regression analyses for factors associated with failure, per 3 tonometric cutoffs. In all models, a high number of pre-procedure medications was associated with an increased risk of procedural failure. Male gender, intraoperative MMC, and late laser goniopuncture were all associated with a reduced risk for failure. Older age was also associated with a reduced failure risk, particularly in high- and mid-teen, but not low-teen, IOP cutoffs.
After laser goniopuncture, iris incarceration occurred in 29 eyes (3.2%). In 6 of these eyes, iris incarceration took place directly after the procedure; only 3 eyes had iris incarcerations after more than 3 years. Cumulative incidence of iris incarceration was 2.1%, 3.4% and 3.6% at each follow-up timepoint.
Results of a multivariable Cox regression analysis showed that later laser goniopuncture was associated with a decreased risk of iris incarceration (for 1 month increase, hazard ratio [HR], 0.936; 95% CI, 0.884-0.991). In 24 cases, iris incarceration was treated successfully with Argon iridoplasty, while 2 eyes required surgical iris repositioning. In 2 eyes, IOP was satisfactory with only topical treatment, while another 2 eyes underwent no further intervention due to low IOP. Ultimately, 6 eyes underwent further glaucoma surgery after a median of 5.5 months (IQR, 3.3-7.0 months).
Serious complications included hypotony maculopathy (2.7%), choroidal effusion (1.4%), bleb-related infection (0.6%), suprachoroidal hemorrhage (0.2%), and aqueous misdirection (0.1%).
Study limitations include the retrospective nature of the research, as well as the irregular visit intervals and the number of patients lost to follow-up, a lack of a control group, potentially missed diagnoses of limited and subclinical iris incarceration, and an inability to determine whether complications were “truly caused” by laser goniopuncture.
“The majority of patients undergoing [deep sclerectomy] will eventually require [laser goniopuncture],” the researchers report. “Overall, [laser goniopuncture] is effective in rescuing eyes with failing [deep sclerectomy], prolonging…success rates, and avoiding additional glaucoma surgery.”
“This study identifies several factors associated with [laser goniopuncture] outcomes, knowledge of which may help the clinician anticipate…efficacy and counsel the patient accordingly,” the study says. “Despite a good safety profile, [laser goniopuncture] is not a risk-free procedure and may lead to serious complications.”
Rabiolo A, Leadbetter D, Kirk J, Anand N. Laser goniopuncture after deep sclerectomy: Incidence, long-term outcomes and risk factors for failure. Br J Ophthalmol. Published online July 20, 2021. doi:10.1136/bjophthalmol-2021.319314