Skip to main content

Clinical utility of ocular residual astigmatism and topographic disparity vector indexes in subclinical and clinical keratoconus

Abstract

Purpose

We aimed to characterize the distribution of the vector parameters ocular residual astigmatism (ORA) and topography disparity (TD) in a sample of clinical and subclinical keratoconus eyes, and to evaluate their diagnostic value to discriminate between these conditions and healthy corneas.

Methods

This study comprised a total of 43 keratoconic eyes (27 patients, 17–73 years) (keratoconus group), 11 subclinical keratoconus eyes (eight patients, 11–54 years) (subclinical keratoconus group) and 101 healthy eyes (101 patients, 15–64 years) (control group). In all cases, a complete corneal analysis was performed using a Scheimpflug photography-based topography system. Anterior corneal topographic data was imported from it to the iASSORT software (ASSORT Pty. Ltd), which allowed the calculation of ORA and TD.

Results

Mean magnitude of the ORA was 3.23 ± 2.38, 1.16 ± 0.50 and 0.79 ± 0.43 D in the keratoconus, subclinical keratoconus and control groups, respectively (p < 0.001). Mean magnitude of the TD was 9.04 ± 8.08, 2.69 ± 2.42 and 0.89 ± 0.50 D in the keratoconus, subclinical keratoconus and control groups, respectively (p < 0.001). Good diagnostic performance of ORA (cutoff point: 1.21 D, sensitivity 83.7 %, specificity 87.1 %) and TD (cutoff point: 1.64 D, sensitivity 93.3 %, specificity 92.1 %) was found for the detection of keratoconus. The diagnostic ability of these parameters for the detection of subclinical keratoconus was more limited (ORA: cutoff 1.17 D, sensitivity 60.0 %, specificity 84.2 %; TD: cutoff 1.29 D, sensitivity 80.0 %, specificity 80.2 %).

Conclusion

The vector parameters ORA and TD are able to discriminate with good levels of precision between keratoconus and healthy corneas. For the detection of subclinical keratoconus, only TD seems to be valid.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

References

  1. 1.

    Piñero DP, Nieto JC, Lopez-Miguel A (2012) Characterization of corneal structure in keratoconus. J Cataract Refract Surg 38:2167–2183

    Article  PubMed  Google Scholar 

  2. 2.

    Alió JL, Piñero DP, Alesón A, Teus MA, Barraquer RI, Murta J, Maldonado MJ, Castro de Luna G, Gutiérrez R, Villa C, Uceda-Montanes A (2011) Keratoconus-integrated characterization considering anterior corneal aberrations, internal astigmatism, and corneal biomechanics. J Cataract Refract Surg 37:552–568

    Article  PubMed  Google Scholar 

  3. 3.

    Piñero DP, Ruiz-Fortes P, Pérez-Cambrodí RJ, Mateo V, Artola A (2014) Ocular residual astigmatism and topographic disparity vector indexes in normal healthy eyes. Cont Lens Ant Eye 37:49–54

    Article  Google Scholar 

  4. 4.

    Alpins NA (1997) New method of targeting vectors to treat astigmatism. J Cataract Refract Surg 23:65–75

    CAS  Article  PubMed  Google Scholar 

  5. 5.

    Alpins N (2001) Astigmatism analysis by the Alpins method. J Cataract Refract Surg 27:31–49

    CAS  Article  PubMed  Google Scholar 

  6. 6.

    Rabinowitz YS (1998) Keratoconus. Surv Ophthalmol 42:297–319

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Piñero DP, Alió JL, Alesón A, Escaf Vergara M, Miranda M (2010) Corneal volume, pachymetry, and correlation of anterior and posterior corneal shape in subclinical and different stages of clinical keratoconus. J Cataract Refract Surg 36:814–825

    Article  PubMed  Google Scholar 

  8. 8.

    Piñero DP, Alió JL, Barraquer RI, Michael R, Jiménez R (2010) Corneal biomechanics, refraction, and corneal aberrometry in keratoconus: an integrated study. Invest Ophthalmol Vis Sci 51:1948–1955

    Article  PubMed  Google Scholar 

  9. 9.

    Gobbe M, Guillon M (2005) Corneal wavefront aberration measurements to detect keratoconus patients. Cont Lens Ant Eye 28:57–66

    Article  Google Scholar 

  10. 10.

    de Sanctis U, Loiacono C, Richiardi L, Turco D, Mutani B, Grignolo FM (2008) Sensitivity and specificity of posterior corneal elevation measured by Pentacam in discriminating keratoconus/subclinical keratoconus. Ophthalmology 115:1534–1539

    Article  PubMed  Google Scholar 

  11. 11.

    Nilforoushan MR, Speaker M, Marmor M, Abramson J, Tullo W, Morschauser D, Latkany R (2008) Comparative evaluation of refractive surgery candidates with Placido topography, Orbscan II, Pentacam, and wavefront analysis. J Cataract Refract Surg 34:623–631

    Article  PubMed  Google Scholar 

  12. 12.

    Schlegel Z, Hoang-Xuan T, Gatinel D (2008) Comparison of and correlation between anterior and posterior corneal elevation maps in normal eyes and keratoconus-suspect eyes. J Cataract Refract Surg 34:789–795

    Article  PubMed  Google Scholar 

  13. 13.

    Ahmadi Hosseini SM, Mohidin N, Abolbashari F, Mohd-Ali B, Santhirathelagan CT (2013) Corneal thickness and volume in subclinical and clinical keratoconus. Int Ophthalmol 33:139–145

    Article  PubMed  Google Scholar 

  14. 14.

    Kozobolis V, Sideroudi H, Giarmoukakis A, Gkika M, Labiris G (2012) Corneal biomechanical properties and anterior segment parameters in forme fruste keratoconus. Eur J Ophthalmol 22:920–930

    Article  PubMed  Google Scholar 

  15. 15.

    Ambrósio R Jr, Alonso RS, Luz A, Coca Velarde LG (2006) Corneal thickness spatial profile and corneal-volume distribution: tomographic indices to detect keratoconus. J Cataract Refract Surg 32:1851–1859

    Article  PubMed  Google Scholar 

  16. 16.

    Fontes BM, Ambrósio Junior R, Jardim D, Velarde GC, Nosé W (2010) Ability of corneal biomechanical metrics and anterior segment data in the differentiation of keratoconus and healthy corneas. Arq Bras Oftalmol 73:333–337

    Article  PubMed  Google Scholar 

  17. 17.

    Fontes BM, Ambrósio R Jr, Jardim D, Velarde GC, Nosé W (2010) Corneal biomechanical metrics and anterior segment parameters in mild keratoconus. Ophthalmology 117:673–679

    Article  PubMed  Google Scholar 

  18. 18.

    Piñero DP, Alió JL, Barraquer RI, Uceda-Montanes A, Murta J (2011) Clinical characterization of corneal ectasia after myopic laser in situ keratomileusis based on anterior corneal aberrations and internal astigmatism. J Cataract Refract Surg 37:1291–1299

    Article  PubMed  Google Scholar 

  19. 19.

    Dunne MC, Elawad ME, Barnes DA (1996) Measurement of astigmatism arising from the internal ocular surfaces. Acta Ophthalmol Scand 74:14–20

    CAS  Article  PubMed  Google Scholar 

  20. 20.

    Uçakhan ÖÖ, Cetinkor V, Özkan M, Kanpolat A (2011) Evaluation of Scheimpflug imaging parameters in subclinical keratoconus, keratoconus, and normal eyes. J Cataract Refract Surg 37:1116–1124

    Article  PubMed  Google Scholar 

  21. 21.

    Miháltz K, Kovács I, Kránitz K, Erdei G, Németh J, Nagy ZZ (2011) Mechanism of aberration balance and the effect on retinal image quality inkeratoconus: optical and visual characteristics of keratoconus. J Cataract Refract Surg 37:914–922

    Article  PubMed  Google Scholar 

  22. 22.

    Touboul D, Bénard A, Mahmoud AM, Gallois A, Colin J, Roberts CJ (2011) Early biomechanical keratoconus pattern measured with an ocular response analyzer: curve analysis. J Cataract Refract Surg 37:2144–2150

    Article  PubMed  Google Scholar 

  23. 23.

    Jafarinasab MR, Feizi S, Karimian F, Hasanpour H (2013) Evaluation of corneal elevation in eyes with subclinical keratoconus andkeratoconus using Galilei double Scheimpflug analyzer. Eur J Ophthalmol 23:377–384

    Article  PubMed  Google Scholar 

  24. 24.

    Visser N, Berendschot TT, Verbakel F, de Brabander J, Nuijts RM (2012) Comparability and repeatability of corneal astigmatism measurements using different measurement technologies. J Cataract Refract Surg 38:1764–1770

    Article  PubMed  Google Scholar 

  25. 25.

    McAlinden C, Khadka J, Pesudovs K (2011) A comprehensive evaluation of the precision (repeatability and reproducibility) of the Oculus Pentacam HR. Invest Ophthalmol Vis Sci 52:7731–7737

    Article  PubMed  Google Scholar 

Download references

Funding

No funding was received for this research.

Conflict of interest

All authors certify that they have no affiliations with or involvement in any organization or entity with any financial interest (such as honoraria; educational grants; participation in speakers' bureaus; membership, employment, consultancies, stock ownership, or other equity interest; and expert testimony or patent-licensing arrangements), or non-financial interest (such as personal or professional relationships, affiliations, knowledge or beliefs) in the subject matter or materials discussed in this manuscript

The authors have no proprietary or commercial interest in the medical devices that are involved in this manuscript.

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards

Informed consent

Informed consent was obtained from all individual participants included in the study.

Author information

Affiliations

Authors

Corresponding author

Correspondence to David P. Piñero.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Piñero, D.P., Pérez-Cambrodí, R.J., Soto-Negro, R. et al. Clinical utility of ocular residual astigmatism and topographic disparity vector indexes in subclinical and clinical keratoconus. Graefes Arch Clin Exp Ophthalmol 253, 2229–2237 (2015). https://doi.org/10.1007/s00417-015-3169-x

Download citation

Keywords

  • Keratoconus
  • Ocular residual astigmatism
  • Corneal topography
  • Topography disparity
  • Corneal astigmatism