May 2004
Volume 45, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2004
Validation of the anterior chamber angle measurements with the Orbscan II system using two extrapolation methods
Author Affiliations & Notes
  • D. Piñero Llorens
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • J. Moreno–Montañes
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • M. Diez–Cuenca
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • P. Fernandez
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • R. Rodriguez–Conde
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • M.J. Maldonado
    Ophthalmology, University Clinic. University of Navarra, Pamplona, Spain
  • Footnotes
    Commercial Relationships  D. Piñero Llorens, None; J. Moreno–Montañes, None; M. Diez–Cuenca, None; P. Fernandez, None; R. Rodriguez–Conde, None; M.J. Maldonado, None.
  • Footnotes
    Support  none
Investigative Ophthalmology & Visual Science May 2004, Vol.45, 5555. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      D. Piñero Llorens, J. Moreno–Montañes, M. Diez–Cuenca, P. Fernandez, R. Rodriguez–Conde, M.J. Maldonado; Validation of the anterior chamber angle measurements with the Orbscan II system using two extrapolation methods . Invest. Ophthalmol. Vis. Sci. 2004;45(13):5555.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Abstract: : Purpose: To compare the iridocorneal angle measurement with conventional Gonioscopy (CG), using the Shaffer classification system, with the Orbscan system (OS), and to evaluate the validity of the OS for measuring the anterior chamber angle (ACA) width. Methods: ACA width evaluation was performed in 83 eyes of 49 subjects ranging in age from 31 to 90 years by an experienced examiner using two devices: the Zeiss four–mirror gonioscopy lens and the OS. With the OS the angles were determined using two extrapolation methods of the iris surface: plane and 2D polynomial. Results: Using CG we obtained 9 eyes with angle opened grade I, 16 eyes with grade II, 18 with grade III and 40 with grade IV. With the OS mean gonioscopic values obtained with the "plane" mode were larger than those measured with the "polynomial" mode (p<0.001). This device was unable to measure 6 of the 9 grade I angles. Among the 4 angle groups, there were statistically significant differences in Orbscan measurements (one–way ANOVA, p<0.001) for each extrapolation mode. Except for the comparison between grade II and III groups with the "polynomial" method, all results within angle groups were significantly different (p<0.01). Mean difference between the angle values obtained using the "plane" and "polynomial" methods was 4.12 ± 8.17 degrees and the range of agreement was 32.02 degrees. Conclusions: The "plane" extrapolation method of the OS is capable of detecting significant differences in the numeric gonioscopic measurements according to Shaffer classification criteria. The "polynomial" extrapolation method of the OS cannot differentiate between angles grade II and III. Both extrapolation methods are unable to quantify some occludable angles and cannot be used interchangeably.

Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • anterior segment • anterior chamber 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×