Visual Field Outcomes in the Primary Tube Versus Trabeculectomy Study

Area of Science:

• Ophthalmology
• Glaucoma Research
• Surgical Interventions

Background:

• The Primary Tube Versus Trabeculectomy (PTVT) Study compared outcomes of two glaucoma surgeries.
• Understanding long-term visual field changes is crucial for managing glaucoma progression.

Purpose of the Study:

• To evaluate and compare visual field progression between tube shunt surgery and trabeculectomy.
• To identify factors influencing visual field outcomes after glaucoma surgery.

Main Methods:

• A multicenter randomized clinical trial involving 155 eyes undergoing either tube shunt surgery or trabeculectomy with mitomycin C.
• Standard automated perimetry (SAP) was used to assess visual fields annually for 5 years.
• Linear mixed-effects models analyzed the rate of change in SAP mean deviation (MD), considering intraocular pressure (IOP) and patient age.

Main Results:

• No statistically significant difference in the mean rate of visual field change (SAP MD) was found between the two surgical groups.
• Eyes with higher intraocular pressure (IOP ≥ 14 mmHg) and less consistent IOP control (<100% of visits with IOP < 18 mmHg) showed significantly faster rates of visual field loss.
• Older age and poorer IOP control were identified as independent risk factors for faster visual field progression.

Conclusions:

• Both tube shunt surgery and trabeculectomy offer comparable visual field preservation in the short to medium term.
• Effective and consistent intraocular pressure management is critical for slowing glaucoma progression, regardless of surgical method.
• Patient age is an important factor to consider when predicting glaucoma progression rates post-surgery.