Clinical Factors Associated With Long-Term OCT Variability in Glaucoma

Area of Science:

• Ophthalmology
• Glaucoma research
• Optical coherence tomography (OCT) imaging

Background:

• Glaucoma management relies on monitoring structural changes, particularly retinal nerve fiber layer thickness (RNFLT).
• Long-term variability in RNFLT measurements can complicate the accurate assessment of glaucoma progression.
• Understanding factors influencing RNFLT variability is crucial for reliable clinical decision-making.

Purpose of the Study:

• To identify clinical factors associated with long-term variability in optical coherence tomography (OCT)-measured retinal nerve fiber layer thickness (RNFLT) in glaucoma patients.
• To enhance the evaluation of longitudinal structural changes in glaucoma using OCT data.

Main Methods:

• Retrospective cohort study including glaucoma eyes with at least 2 years and 4 visits of follow-up.
• RNFLT variability calculated as the absolute error of RNFLT residuals across longitudinal follow-up.
• Multivariable linear mixed models used to assess associations between clinical factors and RNFLT variability, with 10-fold cross-validation.

Main Results:

• African American race, intervening cataract extraction, intervening glaucoma surgeries, and a faster RNFLT thinning rate were associated with greater RNFLT variability.
• Increased visit/testing frequency was associated with smaller RNFLT variability.
• The study included 1140 eyes from 634 patients, with a mean RNFLT variability of 1.51 µm.

Conclusions:

• Clinical factors influencing long-term RNFLT variability in glaucoma have been identified.
• Increasing testing frequency can help reduce measurement variability, especially in high-risk eyes.
• Resetting baseline imaging after procedures like cataract extraction may improve progression detection accuracy.