International Journal of Keratoconus and Ectatic Corneal Diseases

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VOLUME 5 , ISSUE 3 ( September-December, 2016 ) > List of Articles


Keratoconic Bi-aspheric Contact Lenses

Ariela Gordon-Shaag, Philip Fine, Liat Gantz, Arige Gideon-Abousaid, Gad Serero

Citation Information : Gordon-Shaag A, Fine P, Gantz L, Gideon-Abousaid A, Serero G. Keratoconic Bi-aspheric Contact Lenses. Int J Kerat Ect Cor Dis 2016; 5 (3):132-138.

DOI: 10.5005/jp-journals-10025-1134

Published Online: 01-12-2011

Copyright Statement:  Copyright © 2016; The Author(s).



This observational clinical case series examined patients with keratoconus (KC) fit with keratoconic bi-aspheric (KBA) lenses to assess visual acuity (VA), wavefront aberrations, physiological fitting, subjective comfort, and manufacturer's fitting guidelines.

Materials and methods

Seven adult patients (11 eyes, four females, mean age: 34.15 ± 14.12) with nipple cones from the Hadassah Academic College contact lens clinic (Jerusalem, Israel) were fit with KBA lenses by modifying the initial base curve (BC) to obtain an acceptable physiological fit. The uncorrected and corrected distance (D) and near (N) Snellen VA and the ocular wavefront measurements, and responses to a self-administered five-point scale questionnaire were compared after 2 weeks of wear using paired two-tailed t-test or Mann-Whitney U test, as appropriate.


Visual acuity and total root mean square (RMS) improved significantly with the lenses (DVAuncorrected = 0.04 ± 0.02, DVAcorrected = 0.66 ± 0. 22, NVAuncorrected = 0.34 ± 0.30, NVAcorrected = 0.95 ± 0.12). Subjects reported an average of 7.0 ± 2.7 hours of wear daily, with good scores in visual stability, satisfaction with VA and quality of vision, improvement of mood and quality of life, and low scores in foreign body sensation, pain, red eye, and itching during wear, and difficulty with lens removal. An average of two BC modifications from the diagnostic lens were necessary (0.16 mm steeper in nine eyes, 0.27 mm flatter in two eyes).


Keratoconic bi-aspheric lenses can provide 7 hours of comfortable wear, significantly improved VA and total RMS aberrations, alongside subjective satisfaction. Base curve modifications can be reduced by fitting a diagnostic lens 0.75 mm steeper than the flattest keratometry reading.

How to cite this article

Gantz L, Gordon-Shaag A, Gideon-Abousaid A, Serero G, Fine P. Keratoconic Bi-aspheric Contact Lenses. Int J Kerat Ect Cor Dis 2016;5(3):132-138.

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  1. Rigid contact lens fitting relationships in keratoconus. Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study Group. Optom Vis Sci 1999 Oct;76(10):692-699.
  2. Cone location and correction of keratoconus with rigid gas-permeable contact lenses. Cont Lens Anterior Eye 2012 Feb;35(1):17-21.
  3. The epidemiology and etiology of keratoconus. Int J Kerat Ect Cor Dis 2012 Jan-Apr;1(1):7-15.
  4. Prevalence and associated factors of keratoconus in Jerusalem: a cross-sectional study. Ophthalmic Epidemiol 2011 Apr;18(2):91-97.
  5. Prevalence of keratoconus amoung young Arab students in Israel. Int J Ker Ect Cor Dis 2014 Jan-Apr;3(1):9-14.
  6. Keratoconus screening in a Lebanese students’ population. J Fr Ophtalmol 2012 Jan;35(1):23-29.
  7. Prevalence of keratoconus in a population-based study in Shahroud. Cornea 2013 Nov;32(11):1441-1445.
  8. Topographic Keratoconus is not Rare in an Iranian population: the Tehran Eye Study. Ophthalmic Epidemiol 2013 Dec;20(6):385-391.
  9. The prevalence of keratoconus in a young population in Mashhad, Iran. Ophthalmic Physiol Opt 2014 Sep;34(5):519-527.
  10. Short-term outcomes of collagen crosslinking for early keratoconus. J Ophthalmic Vis Res 2011 Jul;6(3):155-159.
  11. Rigid contact lens fitting based on keratometry readings in keratoconus patients: predicting formula. Int J Ophthalmol 2011;4(5):525-528.
  12. Keratoconus. Surv ophthalmol 1998 Jan-Feb;42(4):297-319.
  13. The genetics of keratoconus. Ophthalmol Clin North Am 2003 Dec;16(4):607-620, vii.
  14. Baseline findings in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) study. Invest Ophthalmol Vis Sci 1998 Dec;39(13):2537-2546.
  15. Efron grading scales for contact lens complications. Butterworth-Heinemann, Edinburgh, UK; 1997.
  16. The Contact Lens Impact on Quality of Life (CLIQ) Questionnaire: development and validation. Invest Ophthalmol Vis Sci 2006 Jul;47(7):2789-2796.
  17. The performance of the contact lens dry eye questionnaire as a screening survey for contact lens-related dry eye. Cornea 2002 Jul;21(5):469-475.
  18. Statistical methods for conducting agreement (comparison of clinical tests) and precision (repeatability or reproducibility) studies in optometry and ophthalmology. Ophthalmic Physiol Opt 2011 Jul;31(4):330-338.
  19. Aberrations and topography in normal, keratoconus-suspect, and keratoconic eyes. Optom Vis Sci 2012 Apr;89(4):411-418.
  20. Recent advances in representation of monochromatic aberrations of human eyes. Clin Exp Optom 2004 May;87(3):138-148.
  21. A statistical model of the aberration structure of normal, well-corrected eyes. Ophthalmic Physiol Opt 2002 Sep;22(5):427-433.
  22. Contact lenses in the management of keratoconus. Cornea 2011 Dec;30(12):1510-1516.
  23. Contact lens in keratoconus. Indian J Ophthalmol 2013 Aug;61(8):410-415.
  24. An assessment of the optimal lens fit rate in keratoconus subjects using three-point-touch and apical touch fitting approaches with the rose K2 lens. Eye Contact Lens 2013 Jul;39(4):269-272.
  25. Topography-based RGP lens fitting in normal corneas: the relevance of eyelid and tear film attributes. Eye Contact Lens 2011 Nov;37(6):359-364.
  26. Visual performance and comfort with the Rose K lens for keratoconus. Optom Vis Sci 2002 Aug;79(8):493-501.
  27. A prospective clinical evaluation of a new scleral contact lens for patients with distorted corneas. Int J Kerat Ect Cor Dis 2013;2(1):1-11.
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