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Modelling the normal retinal nerve fibre layer thickness as measured by Stratus optical coherence tomography

  • Jesper Leth HougaardEmail author
  • Carl Ostenfeld
  • Anders Heijl
  • Boel Bengtsson
Clinical Investigation

Abstract

Background

The variation in retinal nerve fibre layer thickness (RNFLT) as measured by Stratus optical coherence tomography (OCT) in healthy subjects may be reduced when the effect on RNFLT measurements of factors other than disease is corrected for, and this may improve the diagnostic accuracy in glaucoma. With this perspective we evaluated the isolated and combined effects of factors potentially affecting the Stratus OCT RNFLT measurements in healthy subjects.

Methods

We included 178 healthy eyes of 178 subjects between 20 and 80 years of age. Participants underwent an extensive eye examination. Stratus OCT RNFLT was measured by three standard protocols, two with high and one with standard image resolution. Effects on RNFLT of age, gender, refractive error, axial length, lens nuclear colour and opalescence, intra-ocular pressure (IOP), and optic disc size were examined by univariate and multivariate analyses.

Results

Age, refractive error, axial length, and lens nuclear colour and opalescence affected RNFLT in univariate analyses, whereas gender, IOP, and optic disc size had no significant effect. In multivariate analyses only age in combination with refractive error, or with axial length, was significant and explained 14.7–17.6% (R 2) of the total variation of RNFLT, approximately 50% more than age alone. RNFLT decreased by 2.6–2.9 μm per increasing decade of age and increased by 1.5–1.8 μm per more positive diopter of spherical equivalent using full-circle measurements of the three standard protocols. These effects varied between measurement sectors.

Conclusions

RNFLT as measured by Stratus OCT standard protocols was significantly affected by age and refractive status. The effect on global RNFLT of a difference in refractive error of 10 diopters corresponded to the effect of a difference in age of 60 years. Theoretically, the effect of refractive status may be explained by artefacts of RNFLT measurement circle placement. The results suggest that the diagnostic accuracy of Stratus OCT may be improved by considering refractive status in addition to age when RNFLT is measured. For this purpose spherical equivalent seems as effective as axial length.

Keywords

Nerve fibre layer thickness Optical coherence tomography Healthy subjects Age Refractive error Lens Optic disc 

Notes

Acknowledgements

This research was supported by grants K2005-74X-1426-13A and K2005-74BI-15375-01A from the Swedish Research Council (Vetenskapsrådet), by the Crown Princess Margareta Foundation for the Visually Handicapped (Stiftelsen Kronprinsessan Margaretas arbetsnämnd för synskadade), by the Margit and Kjell Stoltz Foundation (Margit och Kjell Stoltz´ fond), and by the Järnhardt Foundation (Järnhardts stiftelse).

References

  1. 1.
    Aydin A, Wollstein G, Price LL, Fujimoto JG, Schuman JS (2003) Optical coherence tomography assessment of retinal nerve fiber layer thickness changes after glaucoma surgery. Ophthalmology 110:1506–1511PubMedCrossRefGoogle Scholar
  2. 2.
    Balazsi AG, Rootman J, Drance SM, Schulzer M, Douglas GR (1984) The effect of age on the nerve fiber population of the human optic nerve. Am J Ophthalmol 97:760–766PubMedGoogle Scholar
  3. 3.
    Bayraktar S, Bayraktar Z, Yilmaz OF (2001) Influence of scan radius correction for ocular magnification and relationship between scan radius with retinal nerve fiber layer thickness measured by optical coherence tomography. J Glaucoma 10:163–169PubMedCrossRefGoogle Scholar
  4. 4.
    Bengtsson B, Krakau CE (1992) Correction of optic disc measurements on fundus photographs. Graefes Arch Clin Exp Ophthalmol 230:24–28PubMedCrossRefGoogle Scholar
  5. 5.
    Bowd C, Zangwill LM, Blumenthal EZ, Vasile C, Boehm AG, Gokhale PA, Mohammadi K, Amini P, Sankary TM, Weinreb RN (2002) Imaging of the optic disc and retinal nerve fiber layer: the effects of age, optic disc area, refractive error, and gender. J Opt Soc Am A Opt Image Sci Vis 19:197–207PubMedGoogle Scholar
  6. 6.
    Budenz DL, Michael A, Chang RT, McSoley J, Katz J (2005) Sensitivity and specificity of the StratusOCT for perimetric glaucoma. Ophthalmology 112:3–9PubMedCrossRefGoogle Scholar
  7. 7.
    Chylack LT Jr, Leske MC, McCarthy D, Khu P, Kashiwagi T, Sperduto R (1989) Lens opacities classification system II (LOCS II). Arch Ophthalmol 107:991–997PubMedGoogle Scholar
  8. 8.
    Chylack LT Jr, Leske MC, Sperduto R, Khu P, McCarthy D (1988) Lens Opacities Classification System. Arch Ophthalmol 106:330–334PubMedGoogle Scholar
  9. 9.
    Hougaard JL, Kessel L, Sander B, Kyvik KO, Sorensen TI, Larsen M (2003) Evaluation of heredity as a determinant of retinal nerve fiber layer thickness as measured by optical coherence tomography. Invest Ophthalmol Vis Sci 44:3011–3016PubMedCrossRefGoogle Scholar
  10. 10.
    Jaffe GJ, Caprioli J (2004) Optical coherence tomography to detect and manage retinal disease and glaucoma. Am J Ophthalmol 137:156–169PubMedCrossRefGoogle Scholar
  11. 11.
    Jonas JB, Schmidt AM, Muller-Bergh JA, Schlotzer-Schrehardt UM, Naumann GO (1992) Human optic nerve fiber count and optic disc size. Invest Ophthalmol Vis Sci 33:2012–2018PubMedGoogle Scholar
  12. 12.
    Kanamori A, Escano MF, Eno A, Nakamura M, Maeda H, Seya R, Ishibashi K, Negi A (2003) Evaluation of the effect of aging on retinal nerve fiber layer thickness measured by optical coherence tomography. Ophthalmologica 217:273–278PubMedCrossRefGoogle Scholar
  13. 13.
    Kerrigan-Baumrind LA, Quigley HA, Pease ME, Kerrigan DF, Mitchell RS (2000) Number of ganglion cells in glaucoma eyes compared with threshold visual field tests in the same persons. Invest Ophthalmol Vis Sci 41:741–748PubMedGoogle Scholar
  14. 14.
    Medeiros FA, Zangwill LM, Bowd C, Vessani RM, Susanna R, Jr., Weinreb RN (2005) Evaluation of retinal nerve fiber layer, optic nerve head, and macular thickness measurements for glaucoma detection using optical coherence tomography. Am J Ophthalmol 139:44–55PubMedCrossRefGoogle Scholar
  15. 15.
    Medeiros FA, Zangwill LM, Bowd C, Weinreb RN (2004) Comparison of the GDx VCC scanning laser polarimeter, HRT II confocal scanning laser ophthalmoscope, and Stratus OCT optical coherence tomograph for the detection of glaucoma. Arch Ophthalmol 122:827–837PubMedCrossRefGoogle Scholar
  16. 16.
    Savini G, Zanini M, Carelli V, Sadun AA, Ross-Cisneros FN, Barboni P (2005) Correlation between retinal nerve fibre layer thickness and optic nerve head size: an optical coherence tomography study. Br J Ophthalmol 89:489–492PubMedCrossRefGoogle Scholar
  17. 17.
    Schmitt JM (1999) Optical coherence tomography (OCT): a review. IEEE J Select Topics Quantum Electron 5(4):1205–1215CrossRefGoogle Scholar
  18. 18.
    Schuman JS, Hee MR, Puliafito CA, Wong C, Pedut-Kloizman T, Lin CP, Hertzmark E, Izatt JA, Swanson EA, Fujimoto JG (1995) Quantification of nerve fiber layer thickness in normal and glaucomatous eyes using optical coherence tomography. Arch Ophthalmol 113:586–596PubMedGoogle Scholar
  19. 19.
    Varma R, Bazzaz S, Lai M (2003) Optical tomography-measured retinal nerve fiber layer thickness in normal latinos. Invest Ophthalmol Vis Sci 44:3369–3373PubMedCrossRefGoogle Scholar
  20. 20.
    Wakitani Y, Sasoh M, Sugimoto M, Ito Y, Ido M, Uji Y (2003) Macular thickness measurements in healthy subjects with different axial lengths using optical coherence tomography. Retina 23:177–182PubMedCrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • Jesper Leth Hougaard
    • 1
    Email author
  • Carl Ostenfeld
    • 1
  • Anders Heijl
    • 1
  • Boel Bengtsson
    • 1
  1. 1.Department of Clinical Sciences, Ophthalmology, Malmö University HospitalLund UniversityMalmöSweden

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