A pilot study using "ROPtool" to quantify plus disease in retinopathy of prematurity

David K. Wallace, Zheen Zhao, Sharon F. Freedman

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

Purpose: The accurate diagnosis of plus disease is critical to optimize the timing of laser treatment. Unfortunately, it is highly subjective and error-prone. "ROPtool" is a computer program that automatically traces retinal blood vessels and measures their tortuosity and dilation. Our aims were to pilot ROPtool, determine its reliability and validity, and establish appropriate numerical thresholds for plus and pre-plus disease. Methods: Twenty high-quality images of the posterior poles of premature infants were collected. Two of the authors (DKW and SFF) independently judged tortuosity and dilation separately as plus, pre-plus, or normal for each quadrant of each image. Disagreements were adjudicated, and the results were considered to be the standard for comparison to ROPtool. These two authors then separately used ROPtool to analyze the same 20 images. Results: For determination of tortuosity sufficient for plus disease, ROPtool interuser agreement was 95% (19/20), compared with 90% (18/20) agreement by investigator judgment. Eye-level (2 MDs × 20 eyes) sensitivity of ROPtool in detecting tortuosity sufficient for plus disease averaged 95% (21/22) and specificity averaged 78% (14/18). Quadrant-level (2 MDs × 20 eyes × 4 quadrants) sensitivity averaged 85% (66/78) and specificity averaged 77% (63/82). A numeric threshold for pre-plus disease equal to 70% of the average tortuosity of the standard photograph of plus disease resulted in mean sensitivity of 89% (103/116) and mean specificity of 82% (36/44) in distinguishing quadrant-level tortuosity sufficient for pre-plus disease or worse from normal. Conclusions: ROPtool can reduce subjectivity and thereby enhance the evaluation of plus and pre-plus disease.

Original languageEnglish (US)
Pages (from-to)381-387
Number of pages7
JournalJournal of AAPOS
Volume11
Issue number4
DOIs
StatePublished - Aug 1 2007
Externally publishedYes

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Retinopathy of Prematurity
Dilatation
Retinal Vessels
Reproducibility of Results
Premature Infants
Lasers
Software
Research Personnel

ASJC Scopus subject areas

  • Ophthalmology

Cite this

A pilot study using "ROPtool" to quantify plus disease in retinopathy of prematurity. / Wallace, David K.; Zhao, Zheen; Freedman, Sharon F.

In: Journal of AAPOS, Vol. 11, No. 4, 01.08.2007, p. 381-387.

Research output: Contribution to journalArticle

Wallace, David K. ; Zhao, Zheen ; Freedman, Sharon F. / A pilot study using "ROPtool" to quantify plus disease in retinopathy of prematurity. In: Journal of AAPOS. 2007 ; Vol. 11, No. 4. pp. 381-387.
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