Surgically induced astigmatism and refractive outcomes after minimally invasive glaucoma surgery combined with...

Area of Science:

• Ophthalmology
• Surgical Innovation
• Refractive Surgery

Background:

• Minimally invasive glaucoma surgery (MIGS) is theorized to cause less surgically induced astigmatism (SIA) due to smaller incisions.
• Limited research exists on SIA specifically within MIGS procedures.
• Evaluating refractive outcomes alongside SIA is crucial for patient satisfaction.

Purpose of the Study:

• To compare SIA and refractive outcomes among three distinct MIGS techniques.
• To assess the refractive neutrality of MIGS procedures in various glaucoma subtypes.
• To provide data supporting MIGS as a refractive-stable option when combined with cataract surgery.

Main Methods:

• Retrospective cohort study comparing first-generation iStent (IS), second-generation iStent inject W (IW), and microhook ab interno trabeculotomy (μLOT).
• Analysis included SIA, refractive prediction error (RPE), intraocular pressure (IOP) reduction, and glaucoma subtypes.
• Statistical analysis utilized a linear mixed model to compare outcomes between the three MIGS groups.

Main Results:

• SIA was minimal and not significantly different across the IS, IW, and μLOT groups (p=0.95).
• Refractive prediction error differed significantly between IW and μLOT (p=0.025), but remained mild.
• The μLOT group showed a slight myopic shift and greater IOP reduction; however, absolute prediction error did not significantly differ among groups (p=0.062).

Conclusions:

• MIGS procedures, including IS, IW, and μLOT, demonstrate refractive stability when performed with cataract surgery.
• These MIGS techniques are equally viable from a refractive perspective.
• Subgroup analysis confirmed refractive neutrality across primary open-angle glaucoma, pseudoexfoliative glaucoma, and chronic angle-closure glaucoma.