Intraocular pressure control and long-term visual field loss in the Collaborative Initial Glaucoma Treatment Study

Area of Science:

• Ophthalmology
• Glaucoma Research
• Clinical Trials

Background:

• Open-angle glaucoma (OAG) is a leading cause of irreversible blindness.
• Effective intraocular pressure (IOP) management is crucial for preventing visual field (VF) loss.
• The specific impact of various IOP control measures on long-term VF progression remains under investigation.

Purpose of the Study:

• To evaluate how different measures of IOP control affect the progression of VF loss in OAG patients.
• To compare the association between IOP control metrics and VF outcomes in medication versus surgical treatment groups.

Main Methods:

• A longitudinal, randomized clinical trial involving 607 newly diagnosed OAG participants.
• Participants were randomized to initial treatment with medications or trabeculectomy.
• IOP was measured using Goldmann applanation tonometry, and VF loss was assessed via Humphrey 24-2 tests over 3-9 years. Various IOP summary measures (maximum, SD, range) were analyzed.

Main Results:

• In the medication group, higher maximum IOP, standard deviation (SD) of IOP, and IOP range were significantly associated with worse mean deviation (MD) over time.
• No IOP summary measure was significantly associated with MD progression in the surgery group.
• Black race, higher baseline IOP, and clinical center predicted inadequate IOP control, characterized by high maximum, SD, and range of IOP.

Conclusions:

• IOP variability and elevation, particularly in medication-treated patients, are significant predictors of VF loss in OAG.
• These findings underscore the importance of monitoring IOP fluctuations and considering more aggressive treatment strategies when undue IOP elevation or variation is observed.