Utility of Optical Coherence Tomography (OCT) in Centers For Medicare and Medicaid Services (CMS)-defined Severe Glaucoma Patients.

Abstract

Patients with Centers For Medicare and Medicaid Services (CMS)-defined severe glaucoma often have clinically useful remaining retinal nerve fiber layer (RNFL), suggesting that structurally based rather than functionally based criteria would be more appropriate to use as guidelines for the utilization of optical coherence tomography (OCT) imaging. RNFL OCT in glaucomatous eyes with advanced structural damage can reach a floor after which there is no further detectable thinning of RNFL. Insurers are considering limiting coverage for OCT in "severe stage glaucoma" defined by CMS. However, CMS definitions of severe glaucoma are based primarily on visual field criteria. Many of these patients may have preserved RNFL in other sectors. This study aims to assess the clinical utility of RNFL measurements by OCT in eyes with CMS-defined severe glaucoma. Medical records of patients with CMS-defined severe glaucoma were consecutively reviewed. Data collected included average/sectoral RNFL thickness, and visual field mean deviation. Previous estimates of RNFL floor and test-retest variability for Cirrus OCT were used to establish 3 threshold values of RNFL. Data analysis included descriptive statistics, χ analysis, and analysis of variance. A total of 129 eyes qualified (age: 71±12 y; mean deviation: -13.5±4.3 dB; average RNFL: 60.9±7.9 μm), A majority (66%) of eyes met severe glaucoma criteria with defects in both hemifields; 34% met only paracentral defect criteria. The proportion of eyes that had significant remaining average, superior, or inferior RNFL, estimated by thresholds 1 to 3, was 21% to 54%, 29% to 51%, and 16% to 37%, respectively. At least 1 vertical quadrant had significant remaining RNFL in 35% to 66% of eyes, depending on the threshold used. Our data demonstrate a substantial portion of eyes with CMS-defined severe glaucoma have measurable RNFL above the floor in at least 1 vertical quadrant that may be longitudinally monitored for progression. The presence of CMS-defined severe glaucoma does not exclude the potential utility of OCT to monitor progression.