Nerve Fibre Bundle Shift and Glaucoma Misdiagnosis Risk in a Small Nonconsecutive Series of African American Patients

Alexander Hynes; Alaina Short

doi:10.65636/cjo.v88i1.6569

Authors

Alexander Hynes Nova Southeastern University College of Optometry https://orcid.org/0009-0009-0201-0898
Alaina Short Nova Southeastern University College of Optometry

DOI:

https://doi.org/10.65636/cjo.v88i1.6569

Keywords:

retinal nerve fiber layer (RNFL), glaucoma suspect, normative database, glaucoma, optical coherence tomography (OCT), African American

Abstract

Purpose
To share preliminary observations of how some African American patients may have anatomically shifted superior-temporal and inferior-temporal retinal nerve fibre layer (RNFL) bundle peaks compared with the Cirrus Optical Coherence Tomography (OCT) normative database majority. This discrepancy may yield false-positive thinning on RNFL deviation maps, thereby appearing glaucomatous. Three nonconsecutive African American patients with mild myopia (<2.12 dioptre spherical equivalent) were selected to illustrate this bundle shift. Despite the very limited sample size, our case study may spur more rigorous study with larger cohorts of diverse patients.
Observations
Three patients of African descent presented with cup-to-disc ratios of 0.6 or higher and were flagged with symmetrical bilateral RNFL thinning in superior-temporal and/or inferior-temporal RNFL sectors compared with the Cirrus OCT normative database. All six eyes had discs without significant peripapillary atrophy nor tilt, either of which could be associated with non-glaucomatous OCT defects. Thinning on RNFL deviation maps in each patient showed symmetrical wedge defects toward the superior-temporal and inferior-temporal vulnerability zones of the disc. However, each patient demonstrated robust macular ganglion cell thicknesses and had automated fields inconsistent with glaucoma. On closer inspection, the principal superior-temporal and inferior-temporal RNFL bundle peaks in these patients appeared shifted more vertically (or nasally).
Conclusions
The RNFL anatomy of African American patients may differ from the OCT normative database majority. Each patient in our series had high-risk, yet symmetrically appearing superior-temporal and/or inferior-temporal RNFL thinning, largely attributable to anatomical shifting of these bundle peaks. Ignoring bundle shift has the potential to result in improper glaucoma diagnoses. This is particularly relevant as clinicians are trained to pay particular attention to the superior-temporal and inferior-temporal RNFL sectors as known vulnerabilities to early glaucoma. Correlation of RNFL findings with macular ganglion cell analysis and fields with careful optic nerve assessment is therefore important.

Author Biographies

Alexander Hynes, Nova Southeastern University College of Optometry

Alex is as an Assistant Professor at NSUCO where he serves as a clinical attending in various NSU clinics: glaucoma; ocular surface disease; specialty contact lens; and Broward community health center. He completed a residency in ocular disease/glaucoma at the University of Waterloo in 2018 after graduating from there. He has also completed a clinical fellowship at University of Illinois Chicago's ophthalmology teaching hospital with emphasis in medically necessary contact lenses for ectasia and severe ocular surface disease. He was previously on faculty at the Kentucky College of Optometry for 3 years where he co-taught the ocular anatomy, clinical medicine and glaucoma courses while also learning, performing and later helping teach anterior segment lasers in clinic.

Alaina Short, Nova Southeastern University College of Optometry

Dr Short completed a rural hospital based VA residency with focus in retina, glaucoma and vision rehabilitation at White-river Junction in Vermont in 2020. She subsequently joined the faculty at Kentucky College of Optometry where she cotaught both the Clinical Medicine and the Advanced Topics in Ocular Disease Courses. She also served as a clinical attending and helped run two rural satellite optometry clinics in Eastern Kentucky. In 2024, she joined Nova Southeastern College of Optometry where she currently is Instructor of Record of Anterior Segment Disease as well as the Chief of the Vision Rehabilitation Clinic. She has given multiple CE lectures for the Kentucky Optometric Association.

References

1. Mwanza JC, Warren JL, Budenz DL. Utility of combining spectral domain optical coherence tomography structural parameters for the diagnosis of early glaucoma: A mini-review. Eye Vis. 2018 Apr 15;5:9. https://doi.org/10.1186/s40662-018-0101-6

2. Bussel II, Wollstein G, Schuman JS. OCT for glaucoma diagnosis, screening and detection of glaucoma progression. Br J Ophthalmol. 2014;98 Suppl 2:ii15-ii19. https://doi.org/10.1136/bjophthalmol-2013-304326

3. Addis V, Chan L, Chen J, et al. Evaluation of the cirrus high-definition OCT normative database probability codes in a Black American population. Ophthalmol Glaucoma. 2022;5(1):110-118. https://doi.org/10.1016/j.ogla.2021.05.002

4. Hood DC, La Bruna S, Tsamis E, et al. Detecting glaucoma with only OCT: Implications for the clinic, research, screening, and AI development. Prog Retin Eye Res. 2022;90:101052. https://doi.org/10.1016/j.preteyeres.2022.101052

5. Hood DC. Improving our understanding, and detection, of glaucomatous damage: An approach based upon optical coherence tomography (OCT). Prog Retin Eye Res. 2017;57:46-75. https://doi.org/10.1016/j.preteyeres.2016.12.002

6. Tanna AP. Retinal nerve fiber layer analysis in glaucoma. In: Budenz, DL, ed. Atlas of Optical Coherence Tomography for Glaucoma. Springer Cham. 2020: 31-35. https://doi.org/10.1007/978-3-030-46792-0

7. Mwanza JC, Oakley JD, Budenz DL, Anderson DR. Cirrus Optical Coherence Tomography Normative Database Study Group. Ability of cirrus HD-OCT optic nerve head parameters to discriminate normal from glaucomatous eyes. Ophthalmology. 2011;118(2):241-8.e1. https://doi.org/10.1016/j.ophtha.2010.06.036

8. Hwang YH, Kim YY. Glaucoma diagnostic ability of quadrant and clock-hour neuroretinal rim assessment using cirrus HD optical coherence tomography. Invest Ophthalmol Vis Sci. 2012;53(4):2226-2234. https://doi.org/10.1167/iovs.11-8689

9. Chen JJ, Kardon RH. Avoiding clinical misinterpretation and artifacts of optical coherence tomography analysis of the optic nerve, retinal nerve fiber layer, and ganglion cell layer. J Neuroophthalmol. 2016;36(4):417-438. https://doi.org/10.1097/WNO.0000000000000422

10. Hardin JS, Taibbi G, Nelson SC, Chao D, Vizzeri G. Factors affecting cirrus-HD OCT optic disc scan quality: A review with case examples. J Ophthalmol. 2015; 2015:746150. https://doi.org/10.1155/2015/746150

11. Chong GT, Lee RK. Glaucoma versus red disease: Imaging and glaucoma diagnosis. Curr Opin Ophthalmol. 2012;23(2):79-88.

https://doi.org/10.1097/ICU.0b013e32834ff431

12. Susanna R Jr, Vessani RM. New findings in the evaluation of the optic disc in glaucoma diagnosis. Curr Opin Ophthalmol. 2007;18(2):122-28. https://doi.org/10.1097/ICU.0b013e328040bfe0

13. Knight OJ, Girkin CA, Budenz DL, Durbin MK, Feuer WJ; Cirrus OCT Normative Database Study Group. Cirrus OCT normative database study group. Effect of race, age, and axial length on optic nerve head parameters and retinal nerve fiber layer thickness measured by Cirrus HD-OCT. Arch Ophthalmol. 2012;130(3):312-318. https://doi.org/10.1001/archopthalmol.2011.1576

14. Girkin CA, McGwin G Jr, McNeal SF, DeLeon-Ortega J. Racial differences in the association between optic disc topography and early glaucoma. Invest Ophthalmol Vis Sci. 2003;44(8):3382-3387. https://doi.org/10.1167/iovs.02-0792

15. Nakayama LF, Zago Ribeiro L, de Oliveira JAE, et al. Fairness and generalizability of OCT normative databases: A comparative analysis. Int J Retina Vitreous. 2023;9(1):48. https://doi.org/10.1186/s40942-023-00459-8

16. KhalafAllah MT, Zangwill LM, Proudfoot J, et al. Racial differences in diagnostic accuracy of retinal nerve fiber layer thickness in primary open-angle glaucoma. Am J Ophthalmol. 2024;259:7-14. https://doi.org/10.1016/j.ajo.2023.10.012

17. Moghimi S, Zangwill LM, Hou H, et al. Comparison of peripapillary capillary density in glaucoma patients of African and European descent. Ophthalmol Glaucoma. 2021;4(1):51-62. https://doi.org/10.1016/j.ogla.2020.07.005

18. Girkin CA. Differences in optic nerve structure between individuals of predominantly African and European ancestry: Implications for disease detection and pathogenesis. Clin Ophthalmol. 2008;2(1):65-69. https://doi.org/10.2147/opth.s1628

19. Nousome D, Mckean-Cowdin R, Richter GM, et al. Retinal nerve fiber layer thickness in healthy eyes of Black, Chinese, and Latino Americans: A population-based multiethnic study. Ophthalmology. 2021;128(7):1005-1015. https://doi.org/10.1016/j.ophtha.2020.11.015

20. Hood DC, Fortune B, Arthur SN, et al. Blood vessel contributions to retinal nerve fiber layer thickness profiles measured with optical coherence tomography. J Glaucoma. 2008;17(7):519-528. https://doi.org/10.1097/IJG.0b013e3181629a02

21. Wang M, Jin Q, Wang H, et al. The interrelationship between refractive error, blood vessel anatomy, and glaucomatous visual field loss. Transl Vis Sci Technol. 2018;7(1):4. https://doi.org/10.1167/tvst.7.1.4

22. Leung CK, Yu M, Weinreb RN, et al. Retinal nerve fiber layer imaging with spectral-domain optical coherence tomography: A prospective analysis of age-related loss. Ophthalmology. 2012;119(4):731-737. https://doi.org/10.1016/j.ophtha.2011.10.010

23. Mendieta N, Suárez J, Barriga N, Herrero R, Barrios B, Guarro M. How do patients feel about visual field testing? Analysis of subjective perception of standard automated perimetry. Semin Ophthalmol. 2021;36(1-2):35-40. https://doi.org/10.1080/08820538.2021.1884270

24. Kim YW, Park KH. Macular parameters For Glaucoma. In: Budenz, DL, ed. Atlas of Optical Coherence Tomography for Glaucoma. Springer Cham. 2020: 77-95. https://doi.org/10.1007/978-3-030-46792-0

25. Hood DC, Raza AS, de Moraes CG, Liebmann JM, Ritch R. Glaucomatous damage of the macula. Prog Retin Eye Res. 2013;32:1-21.

https://doi.org/10.1016/j.preteyeres.2012.08.003

26. Lee J, Kim YK, Ha A, et al. Temporal raphe sign for discrimination of glaucoma from optic neuropathy in eyes with macular ganglion cell-inner plexiform layer thinning. Ophthalmology. 2019;126(8):1131-1139. https://doi.org/10.1016/j.ophtha.2018.12.031

27. Realini T, Zangwill LM, Flanagan JG, et al. Normative databases for imaging instrumentation. J Glaucoma. 2015;24(6):480-483. https://doi.org/10.1097/IJG.0000000000000152