Using an Image Fusion Methodology to Improve Efficiency and Traceability of Posterior Pole Vessel Analysis by ROPtool

ROPtool analysis of plus and pre-plus disease in narrow-field images: a multi-image quadrant-level approach

BACKGROUND

The presence of plus disease is important in determining when to treat retinopathy of prematurity (ROP), but the diagnosis of plus disease is subjective. Semiautomated computer programs (eg, ROPtool) can objectively measure retinal vascular characteristics in retinal images, but are limited by image quality. The purpose of this study was to evaluate whether ROPtool can accurately identify pre-plus and plus disease in narrow-field images of varying qualities using a new methodology that combines quadrant-level data from multiple images of a single retina.

METHODS

This was a cross-sectional study of previously collected narrow-field retinal images of infants screened for ROP. Using one imaging session per infant, we evaluated the ability of ROPtool to analyze images using our new methodology and the accuracy of ROPtool indices (tortuosity index [TI], maximum tortuosity [T_max], dilation index [DI], maximum dilation [D_max], sum of adjusted indices [SAI], and tortuosity-weighted plus [TWP]) to identify pre-plus and plus disease in images compared to clinical examination findings.

RESULTS

Of 198 eyes (from 99 infants) imaged, 769/792 quadrants (98%) were analyzable. Overall, 98% of eyes had 3-4 analyzable quadrants. For plus disease, area under the curves (AUCs) of receiver operating characteristic curves were: TWP (0.98) > TI (0.97) = T_max (0.97) > SAI (0.96) > DI (0.88) > D_max (0.84). For pre-plus or plus disease, AUCs were: TWP (0.95) > TI (0.94) = T_max (0.94) = SAI (0.94) > DI (0.86) > D_max (0.83).

CONCLUSIONS

Using a novel methodology combining quadrant-level data, ROPtool can analyze narrow-field images of varying quality to identify pre-plus and plus disease with high accuracy.

Telemedicine for ROP

With the increasing survival of preterm babies in the Asia-Pacific region, there has been an increase in the incidence of retinopathy of prematurity (ROP). There is also a lack of trained ophthalmologists to screen for this disease. New strategies for screening of ROP are required, wherein the load on the ophthalmologist can be reduced. Telemedicine is an excellent tool to address this need. This paper reviews the initial studies comparing digital imaging with indirect ophthalmoscopy, the current active ROP telescreening programs in the world, and ends with studies dealing with automated diagnosis of ROP.