July 2020
Volume 61, Issue 9
Open Access
ARVO Imaging in the Eye Conference Abstract  |   July 2020
Single point versus zonal maximum keratometry in the assessment of CXL efficacy
Author Affiliations & Notes
  • Shiva Mehravaran
    Morgan State University, Baltimore, Maryland, United States
  • Hassan Hashemi
    Noor Ophthalmology Research Center, Iran (the Islamic Republic of)
  • Kazem Amanzadeh
    Noor Ophthalmology Research Center, Iran (the Islamic Republic of)
  • Mohammad Seyedian
    Noor Ophthalmology Research Center, Iran (the Islamic Republic of)
  • Hojjat Zeraati
    Noor Ophthalmology Research Center, Iran (the Islamic Republic of)
  • Cynthia J Roberts
    The Ohio State University, Ohio, United States
  • Renato Ambrósio
    Federal University of the State of Rio de Janeiro (UNIRIO), Brazil
  • Md Rahman
    Morgan State University, Baltimore, Maryland, United States
  • Riccardo Vinciguerra
    Humanitas San Pio X Hospital, Italy
  • Paolo Vinciguerra
    Humanitas University, Italy
  • Soheila Asgari
    Noor Ophthalmology Research Center, Iran (the Islamic Republic of)
  • Footnotes
    Commercial Relationships   Shiva Mehravaran, None; Hassan Hashemi, None; Kazem Amanzadeh, None; Mohammad Seyedian, None; Hojjat Zeraati, None; Cynthia Roberts, Oculus (C); Renato Ambrósio, Oculus (C); Md Rahman, None; Riccardo Vinciguerra, Oculus (C); Paolo Vinciguerra, Oculus (C); Soheila Asgari, None
  • Footnotes
    Support  National Institute for Medical Research Development (NIMAD) # 973289
Investigative Ophthalmology & Visual Science July 2020, Vol.61, PB0071. doi:
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      Shiva Mehravaran, Hassan Hashemi, Kazem Amanzadeh, Mohammad Seyedian, Hojjat Zeraati, Cynthia J Roberts, Renato Ambrósio, Md Rahman, Riccardo Vinciguerra, Paolo Vinciguerra, Soheila Asgari; Single point versus zonal maximum keratometry in the assessment of CXL efficacy. Invest. Ophthalmol. Vis. Sci. 2020;61(9):PB0071.

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

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Abstract

Purpose : To compare the safety and efficacy of an accelerated cross-linking (CXL) protocol (9mW/cm2, 10 minutes) with standard CXL (3mW/cm2, 30 minutes) in patients with keratoconus (KC) and Down Syndrome (DS) using single point maximum keratometry (Kmax) and zonal-Kmax.

Methods : In this non-inferiority contralateral randomized clinical trial based on good clinical practice principles, 27 DS patients (age range: 10 to 20 years) with bilateral progressive KC who were identified over an 18-month monitoring period were enrolled in the study and completed follow-up exams for one year. Fellow eyes were randomly allocated to the accelerated or standard CXL groups. Zonal Kmax was defined as the average keratometry in the 3mm zone surrounding the point of maximum keratometry, as measured with Pentacam. Vision and refraction tests, ophthalmic examinations, and corneal tomography were done at baseline and at 6 and 12 months after the procedure. The main outcome measure was an inter-group difference of ≤1.0 diopter (D) in Kmax. Failure was defined as ≥1.0D increase in Kmax, ≥1.0D increase in astigmatism, or ≥2.0% reduction in minimum corneal thickness.

Results : The mean age of the sample was 15.71±2.40 years. At one year, mean changes in single point Kmax in the accelerated and standard CXL groups were +0.61±1.02D and -0.46±1.25D, and failure rates based on this index were 32.1% and 11.1%, respectively. In the subgroup of failed cases, single point Kmax at baseline was 51.33±3.90D and 54.90±0.01D in the accelerated and standard CXL groups, respectively. Mean changes in zonal Kmax in the accelerated and standard CXL groups were +0.27±0.90D and -0.27 ±0.82D, and failure rates based on this index were 22.2% and 0.0%, respectively. In the subgroup of failed cases in the accelerated CXL group zonal Kmax at baseline was 48.90±3.12D.

Conclusions : Based on results with zonal Kmax, in pediatric DS patients with Kmax around 50.0D, the accelerated protocol could halt disease progression and be an alternative for standard CXL. Based on single point Kmax, however, the accelerated protocol is not as effective as standard CXL for cases with Kmax ≤50D.

This is a 2020 Imaging in the Eye Conference abstract.

 

Kamx = single point of greates curvature.
Zonal Kmax = average of a specified region of greatest curvature.

Kamx = single point of greates curvature.
Zonal Kmax = average of a specified region of greatest curvature.

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