Structural evaluation with OCT and functional testing with visual fields should be used throughout the glaucoma disease continuum to detect progression.
This article ws reviewed by Felipe A. Mediros, MD, PhD
Glaucoma worsens slowly in most patients who are affected with the disease, but a substantial number of patients with glaucoma show at least moderate progression over time based on monitoring with optical coherence tomography (OCT) and visual fields.
Although OCT can detect progression in patients across all stages of disease, the findings from OCT and standard automated perimetry (SAP) frequently disagree.
Therefore, it is essential that patients who have been diagnosed with glaucoma be followed for progression using both modalities, according to Felipe A. Medeiros, MD, PhD, Distinguished Professor of Ophthalmology, and Joseph A.C. Wadsworth Endowed Chairman, Duke University School of Medicine, Durham, NC.
The above information and recommendations made by Dr. Medeiros are based on findings from analyses of data collected in the Duke Glaucoma Registry Study from over 27,000 eyes of over 14,000 patients with glaucoma or who were glaucoma suspects.
During follow-up that ranged to almost 9 years, this large patient cohort had undergone more than 100,000 tests with spectral-domain (SD) OCT.
“We believe our undertaking is probably the largest analysis of longitudinal SD OCT and SAP results to date,” Dr. Medeiros said. “Visual field testing remains the primary method of assessing glaucomatous progression. The findings of our study are helpful for understanding where OCT is useful.”
In analyzing the data, eyes were categorized as having slow, moderate, fast, or catastrophic change over time based on average annual change in SAP or average retinal nerve fiber layer (RNFL) thickness change criteria. For example, eyes with <0.5 dB/year change in SAP or <1 μm/year loss of average RNFL were classified as experiencing slow change.
Dr. Medeiros explained that the cut-off of <1 μm/year was chosen to define slow change based on findings of a study that looked at the impact of normal aging on change in RNFL thickness.