The ICD-10 Glaucoma Severity Score Underestimates the Extent of Glaucomatous Optic Nerve Damage

Am J Ophthalmol. 2022 Dec:244:133-142. doi: 10.1016/j.ajo.2022.08.009. Epub 2022 Aug 23.

Abstract

Purpose: To evaluate the International Classification of Disease, Tenth Revision (ICD-10) codes used for glaucoma severity classification, which are based on the location of visual field (VF) defects; given the known poor sensitivity of the 24-2 visual field test to early disease and macular damage, we hypothesized that the ICD-10 codes would not accurately reflect the extent of glaucomatous damage.

Design: Retrospective validity and reliability analysis.

Methods: We evaluated 80 eyes with glaucomatous optic neuropathy (GON). Masked reviewers assigned an ICD-10 severity grade based on 24-2 VF. Two additional masked examiners determined the presence of optical coherence tomography (OCT) structural damage in each hemifield and/or central 5 degrees to define an OCT-based equivalent ICD-10 classification.

Results: A total of 80 eyes with GON were classified as mild, moderate and advanced in 15, 23, and 42 cases, respectively, based on the 24-2 VF, and in 6, 7, and 67 cases, respectively, based on OCT. The OCT classifications were more severe in 29 of 80 cases (36%). In 33 cases (41.3%), macular damage detected by OCT was missed by the 24-2. In 4 of 80 cases (5%), the VF overestimated the severity, likely due to variability of the 24-2 test.

Conclusions: The ICD-10 system relies solely on damage seen on the 24-2 and as provides a 24-2 functional score rather than a "glaucoma" severity score. OCT revealed wide variation of damage across grades, with a significant proportion of the eyes showing macular structural damage missed with the 24-2 VF. Adding OCT information to the ICD-10 system would help it to more accurately reflect the extent of glaucomatous damage.

Keywords: Glaucoma; ICD-10; Optical coherence tomography; Perimetry; Severity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Glaucoma* / diagnosis
  • Humans
  • International Classification of Diseases
  • Intraocular Pressure
  • Nerve Fibers
  • Optic Nerve
  • Optic Nerve Diseases* / diagnosis
  • Reproducibility of Results
  • Retinal Ganglion Cells
  • Retrospective Studies
  • Tomography, Optical Coherence / methods
  • Vision Disorders
  • Visual Field Tests / methods
  • Visual Fields