Microinvasive glaucoma surgeries: critical summary of clinical trial data with and without phacoemulsification

Long-term outcomes of phacoemulsification with iStent inject® implantation in narrow angle glaucoma

PURPOSE

To assess the outcomes of phacoemulsification with iStent inject implantation (phaco-iStent) in patients with narrow angle glaucoma (NAG) at a single tertiary eye centre.

DESIGN

Retrospective clinical cohort study.

METHODS

Patients undergoing phaco-iStent for NAG between March 2018 and October 2020 under the glaucoma team at a tertiary referral hospital were included. Data was analysed from a surgical outcome database. Primary outcomes included postoperative change in the mean intraocular pressure (IOP) and medications. Success was defined at two IOP cut-off points:≤21mmHg and≤15mmHg with (qualified) or without (complete) drops. Failure was repeat glaucoma surgery or loss of light perception (LP).

RESULTS

Fifty-seven eyes with a mean follow-up of 32months (range 12months to 36months) were included. Mean IOP changed from 19.7±4.2mmHg (range 12-28) to 14.0, 14.9 and 14.6 at 12, 24 and 36months. Drops reduced from 2.2±0.7 to 0.92±1.24 at the last follow-up. Complete success for an IOP≤21mmHg was 49%, 39%, 37% and qualified success was 96%, 92% and 95% at 12, 24 and 36months. An IOP≤15mmHg (qualified) was achieved in 74%, 58%, 54% at 6, 12, 24 and 36months. Three patients (5%) required further glaucoma surgery, one patient underwent selective laser trabeculoplasty and one patient requiring peri-ocular steroid treatment due to persistent cystoid macular oedema. There were no other long-term complications.

CONCLUSION

Phacoemulsification with iStent inject is a safe and effective surgical option in the management of narrow angle glaucoma.

Historical and Contemporary Debates in Schlemm's Canal-Based MIGS

Glaucoma is one of the primary causes of blindness worldwide. Canal opening surgery, a type of minimally invasive glaucoma surgery (MIGS) applied in cases of mild to moderate glaucoma, has gained increasing popularity in recent years due to its efficacy in reducing the intraocular pressure, its safety profile, the simplicity of its technique, and the reduced likelihood of compromised vision. Nevertheless, the existing body of histopathological studies remains insufficient for a comprehensive understanding of post-surgical wound healing. Consequently, debates persist among researchers regarding the mechanism through which Schlemm's canal opening surgery reduces the intraocular pressure, as well as the surgical techniques that may impact the outcomes and the factors influencing surgical success. As the history of MIGS is relatively short and lacks sufficient systemic reviews or meta-analyses evaluating the influence of individual factors, this review was conducted to illuminate the disparities in researchers' opinions at the current stage of research.

Alternatives to Topical Glaucoma Medication for Glaucoma Management

Topical glaucoma medications have favorable safety and efficacy, but their use is limited by factors such as side effects, nonadherence, costs, ocular surface disease, intraocular pressure fluctuations, diminished quality of life, and the inherent difficulty of penetrating the corneal surface. Although traditionally these limitations have been accepted as an inevitable part of glaucoma treatment, a rapidly-evolving arena of minimally invasive surgical and laser interventions has initiated the beginnings of a reevaluation of the glaucoma treatment paradigm. This reevaluation encompasses an overall shift away from the reactive, topical-medication-first default and a shift toward earlier intervention with laser or surgical therapies such as selective laser trabeculoplasty, sustained-release drug delivery, and micro-invasive glaucoma surgery. Aside from favorable safety, these interventions may have clinically important attributes such as consistent IOP control, cost-effectiveness, independence from patient adherence, prevention of disease progression, and improved quality of life.