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.
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.
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 %).
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.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
Piñero DP, Nieto JC, Lopez-Miguel A (2012) Characterization of corneal structure in keratoconus. J Cataract Refract Surg 38:2167–2183
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
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
Alpins NA (1997) New method of targeting vectors to treat astigmatism. J Cataract Refract Surg 23:65–75
Alpins N (2001) Astigmatism analysis by the Alpins method. J Cataract Refract Surg 27:31–49
Rabinowitz YS (1998) Keratoconus. Surv Ophthalmol 42:297–319
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
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
Gobbe M, Guillon M (2005) Corneal wavefront aberration measurements to detect keratoconus patients. Cont Lens Ant Eye 28:57–66
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
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
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
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
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
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
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
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
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
Dunne MC, Elawad ME, Barnes DA (1996) Measurement of astigmatism arising from the internal ocular surfaces. Acta Ophthalmol Scand 74:14–20
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
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
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
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
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
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
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.
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 was obtained from all individual participants included in the study.
About this article
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
- Ocular residual astigmatism
- Corneal topography
- Topography disparity
- Corneal astigmatism