Number of macula optical coherence tomography scans needed to detect glaucoma progression

Area of Science:

• Ophthalmology
• Medical Imaging
• Glaucoma Research

Background:

• Glaucoma progression monitoring is crucial for timely intervention.
• Optical coherence tomography (OCT) enables quantitative assessment of retinal nerve fiber layer and ganglion cell complex (GCC) thickness.
• Detecting statistically significant progression relies on testing frequency and disease rate.

Purpose of the Study:

• To evaluate how testing frequency impacts the time needed to detect statistically significant glaucoma progression in GCC thickness using OCT.
• To determine optimal OCT testing intervals for efficient glaucoma management.

Main Methods:

• Analysis of longitudinal GCC thickness data from 332 eyes of 201 glaucoma patients over an average of 4.4 years.
• Linear regression to calculate GCC thickness change rates.
• Computer simulation to assess time to progression detection at various loss rates and testing frequencies (1-3 times/year).

Main Results:

• Increased OCT testing frequency reduced the time to detect significant GCC thinning.
• With a GCC loss rate of -1 µm/year, progression was detected in 3.8, 2.6, and 2.2 years for annual, semi-annual, and tri-annual testing, respectively.
• With a GCC loss rate of -1.5 µm/year, progression was detected in 3.3, 2.2, and 1.8 years for annual, semi-annual, and tri-annual testing, respectively.

Conclusions:

• Testing macular OCT three times per year offers more sensitive progression detection than twice per year.
• Twice-yearly OCT testing may be sufficient for clinical detection of glaucoma progression while potentially reducing healthcare burden.