June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Comparison of Fundus quantitative Autofluorescence (qAF) Analysis on Heidelberg Eye Explorer (HEYEX) and IGOR Pro QuantAF Software
Author Affiliations & Notes
  • Ryan Larochelle
    New York University School of Medicine, New York, New York, United States
  • Julia Margaret Agee
    New York University School of Medicine, New York, New York, United States
  • Meleha Ahmad
    New York University School of Medicine, New York, New York, United States
  • Nicole Topilow
    New York University School of Medicine, New York, New York, United States
  • Samantha Ayoub
    New York University School of Medicine, New York, New York, United States
  • Nathaniel Tracer
    New York University School of Medicine, New York, New York, United States
  • Theodore Smith
    New York University School of Medicine, New York, New York, United States
  • Footnotes
    Commercial Relationships   Ryan Larochelle, None; Julia Agee, None; Meleha Ahmad, None; Nicole Topilow, None; Samantha Ayoub, None; Nathaniel Tracer, None; Theodore Smith, None
  • Footnotes
    Support  NIH R01 EY015520
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 1582. doi:
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      Ryan Larochelle, Julia Margaret Agee, Meleha Ahmad, Nicole Topilow, Samantha Ayoub, Nathaniel Tracer, Theodore Smith; Comparison of Fundus quantitative Autofluorescence (qAF) Analysis on Heidelberg Eye Explorer (HEYEX) and IGOR Pro QuantAF Software. Invest. Ophthalmol. Vis. Sci. 2017;58(8):1582.

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

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Abstract

Purpose : Heidelberg Engineering’s Spectralis confocal scanning laser ophthalmoscope (cSLO) and HEYEX analysis module are currently used in a research capacity to study fluorophores in the retinal pigment epithelium. No study has demonstrated equivalency of this proprietary analysis process to the previous research standard, an IGOR program called QuantAF, developed by Delori et al [IOVS, 2011], and available to the research team. Our purpose was to compare qAF calculated from the same images of normal phakic and pseudophakic eyes on HEYEX and IGOR QuantAF.

Methods : We analyzed qAF imaging of 38 subjects (59 eyes) using HEYEX and calculated the qAF-8, which is the mean qAF of the middle ring of the Delori grid. To create images compatible with IGOR QuantAF, HEYEX images were resized and the reference images were shifted into the retinal field. These images were processed on IGOR QuantAF to calculate a second qAF-8. We then compared qAF-8 values obtained by each method of analysis with all parameters equal, including age, corneal curvature, electronic zero, scaling factor, and reference calibration factor. Grid placement on the IGOR software was adjusted to match closely the automatic grid on the HEYEX.

Results : qAF-8 values had consistent upward trends with age on both softwares as expected (Greenberg, PMID 23860757). HEYEX qAF-8 values were positively correlated with IGOR qAF-8 values for the same images (Pearson correlation coefficient, r = 0.867). However, values for the same image could differ as much as 90 qAF units (Fig), for reasons that were not clear. The only component of the calculations not accessible for comparison was the proprietary HEYEX software.

Conclusions : Consistent trends and correlations observed with both HEYEX and IGOR QuantAF softwares on the same images demonstrate that HEYEX qAF values may be comparable to previous normative values calculated on IGOR QuantAF. However, individual readings for clinical use could be disparate. Given the clinical potential for diagnostic use of qAF, analysis should be continued over the course of future research to understand how qAF values obtained with newer integrated systems may be made completely compatible with the gold standard published research methods.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Figure. Quantitative Autofluorescence (qAF) values for 38 normal subjects (59 eyes) obtained using HEYEX and IGOR QuantAF softwares on the same images.

Figure. Quantitative Autofluorescence (qAF) values for 38 normal subjects (59 eyes) obtained using HEYEX and IGOR QuantAF softwares on the same images.

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