Glaucoma is one of the leading causes of irreversible vision loss worldwide. Elevated intraocular pressure (IOP) is the most important risk factor for the development and progression of the disease.
Ab-interno trabeculotomy (AIT) using the Trabectome system is a minimally invasive glaucoma surgery (MIGS) that reduces aqueous humor outflow resistance by ablating the trabecular meshwork and the inner wall of Schlemm's canal, thereby lowering intraocular pressure.
Previous studies have demonstrated good short-term efficacy of this procedure. However, robust long-term data spanning several years remain scarce.
The aim of this study is to evaluate the long-term outcomes of AIT in glaucoma patients who underwent surgery between 2019 and 2021 at the Department of Ophthalmology, University Hospital Würzburg. Patients are invited for a single study visit at which intraocular pressure, visual acuity, anterior chamber angle by gonioscopy, and optic nerve structure by optical coherence tomography (OCT) are assessed. The collected data are compared with pre-operative baseline values obtained from medical records.
The results are intended to improve the assessment of long-term surgical success and to optimize patient selection for this procedure in the future.
Diagnosis of glaucoma
Previous ab-interno trabeculotomy (AIT) using the Trabectome device performed at the Department of Ophthalmology, University Hospital Würzburg
Surgery performed between 2019 and 2021
Ability to provide written informed consent
Inability to attend the study visit
Withdrawal of informed consent
Insufficient medical records for pre-operative baseline data retrieval
Patients with glaucoma who underwent ab-interno trabeculotomy (AIT) using the Trabectome device at the Department of Ophthalmology, University Hospital Würzburg, between 2019 and 2021. Patients were identified retrospectively through surgical records and invited for a single prospective follow-up visit in order of longest time elapsed since surgery, prioritizing those operated earliest within the inclusion period.
Cohort
Prospective
Ab-interno trabeculotomy
Procedure/SurgeryAb-interno trabeculotomy (AIT) is a minimally invasive glaucoma surgery (MIGS) performed using the Trabectome device. The procedure ablates the trabecular meshwork and the inner wall of Schlemm's canal via an ab-interno approach, thereby reducing resistance to aqueous humor outflow and lowering intraocular pressure. The surgery is performed under local or general anesthesia and can be combined with cataract surgery. In this observational study, the intervention was performed prior to study enrollment; no surgical intervention is performed as part of the study itself.
Change in Intraocular Pressure (IOP) from Pre-operative Baseline to Follow-up
Mean intraocular pressure (mmHg) measured by Goldmann applanation tonometry at the study visit, compared to pre-operative baseline IOP obtained from medical records. Surgical success is defined as IOP reduction of ≥20% from baseline and/or IOP ≤18 mmHg, with or without anti-glaucomatous medication.
Change in Number of Intraocular Pressure-Lowering Medications from Pre-operative Baseline to Follow-up
Total number of topical and systemic anti-glaucomatous medications used by the patient at the time of the study visit, compared to the number documented in medical records prior to surgery. Reduction in medication burden is considered an additional indicator of surgical success.
Visual Acuity at Follow-up
Visual acuity assessed using standardized visual acuity charts at the study visit. Results are recorded in decimal notation and converted to logMAR for analysis. Pre-operative VA is obtained from medical records for comparison.
Peripapillary Retinal Nerve Fiber Layer (RNFL) Thickness as Measured by Optical Coherence Tomography (OCT)
Peripapillary RNFL thickness (µm) assessed by spectral- domain optical coherence tomography (SD-OCT) at the study visit. Global and sectoral RNFL values are recorded. Results are compared to pre-operative OCT data from medical records where available, to evaluate structural progression of glaucomatous optic neuropathy.
Rate of Surgical Failure Requiring Additional IOP-Lowering Intervention After Ab-Interno Trabeculotomy
Proportion of patients who required additional surgical or laser intervention (e.g., trabeculectomy, tube shunt implantation, selective laser trabeculoplasty) due to insufficient IOP control following AIT. Data obtained retrospectively from medical records. Surgical failure is defined as the need for re-intervention at any time point after the primary procedure.
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