Quantitatively comparing weekly changes in retinal vascular characteristics of eyes eventually treated versus not treated for retinopathy of prematurity.

PURPOSE: To quantitatively compare retinal vascular characteristics over time in eyes eventually treated versus not treated for retinopathy of prematurity (ROP), using ROPtool analysis of narrow-field retinal images. METHODS: This longitudinal study used prospectively collected narrow-field retinal images of infants screened for ROP, prior to treatment, if needed. Images were analyzed using a methodology that combines quadrant-level measures from several images of the same eye. For the longitudinal analysis, one examination per postmenstrual age (PMA) was included per eye. We compared the following ROPtool indices and their change per week between eyes eventually treated versus not treated for ROP: tortuosity index (TI), dilation index (DI), sum of adjusted indices (SAI), and tortuosity-weighted plus (TWP). Analysis was performed on three levels: eye (mean value/eye), quadrant (highest quadrant value/eye), and blood vessel (highest blood vessel value/eye). RESULTS: Of 832 examinations (99 infants), 745 images (89.5%) had 3-4 quadrants analyzable by ROPtool. On the eye level, ROPtool indices differed between eyes eventually treated versus not treated at PMA of 33-35 and 37 weeks for TI, SAI, and TWP, and at PMA of 33-34 and 37 weeks for DI (P ≤ 0.0014), and change per week differed between eyes eventually treated versus not treated only for SAI at PMA of 32 weeks (P < 0.001). CONCLUSIONS: Quantitative analysis of retinal vascular characteristics using ROPtool can help predict eventual need for treatment for ROP as early as 32 weeks PMA. ROPtool index values were more useful than change in these indices to predict eyes that would eventually need treatment for ROP.

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 [Tmax], dilation index [DI], maximum dilation [Dmax], 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) = Tmax (0.97) > SAI (0.96) > DI (0.88) > Dmax (0.84). For pre-plus or plus disease, AUCs were: TWP (0.95) > TI (0.94) = Tmax (0.94) = SAI (0.94) > DI (0.86) > Dmax (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.

Evaluating a Portable, Noncontact Fundus Camera for Retinopathy of Prematurity Screening by Nonophthalmologist Health Care Workers.

PURPOSE: To evaluate (1) the feasibility of non-ophthalmologist healthcare workers (HCWs) to obtain images of sufficient quality for retinopathy of prematurity (ROP) screening using a FDA-approved portable, non-contact, narrow-field fundus camera (i.e., Pictor™), and (2) the accuracy of grading these images to identify infants who developed treatment-warranted (type 1) ROP. DESIGN: Prospective cohort study. SUBJECTS: Infants undergoing routine ROP screening examinations (i.e. birth weight ≤1500 grams and/or gestational age ≤30 weeks or selected infants with a birth weight of 1500-2000g or gestational age >30 weeks and an unstable clinical course). METHODS: We prospectively recruited infants undergoing ROP screening examinations at a community hospital. On the same day an ophthalmologist examined them, a trained HCW imaged their retinas using the non-contact camera. Two masked ROP experts graded these images remotely. We calculated both the percentage of gradable images (i.e. having at least 3 quadrants with sufficient image quality), as well as the accuracy of identifying infants who developed type 1 ROP. MAIN OUTCOME MEASURES: Percentage of gradable images and the sensitivity and specificity of each grader for identifying infants with type 1 ROP by grading for the presence of pre-plus or plus disease. RESULTS: Ninety-nine infants were included. Overall, 92.4% and 94.2% of all infant imaging sessions were considered gradable by graders 1 and 2, respectively. Amongst gradable images, the sensitivity of both graders for identifying type 1 ROP by grading for the presence of pre-plus or plus disease was 100% (95% confidence interval (CI): 95-100%) and the specificity 91% (95% CI: 83-95%) for grader 1 and 93% (95% CI: 86-96%) for grader 2. CONCLUSIONS: It was highly feasible for trained HCWs to obtain digital retinal images of sufficient quality for ROP screening using a non-contact fundus camera. By grading for the presence of pre-plus or plus disease, graders identified infants who developed type 1 ROP with high sensitivity and specificity. The use of portable, non-contact retinal cameras by trained HCWs could increase our workforce in ROP screening and identify infants needing an indirect ophthalmoscopy examination by an ophthalmologist.

Non-contact retinal imaging compared to indirect ophthalmoscopy for retinopathy of prematurity screening: infant safety profile.

OBJECTIVE: Most retinopathy of prematurity screening involves an ophthalmologist performing indirect ophthalmoscopy, which can be stressful to infants. The purpose of this study is to evaluate the safety profile (using cardiopulmonary events as an indicator) of imaging infants with a non-contact retinal camera compared to examining them using indirect ophthalmoscopy. STUDY DESIGN: Prospective cohort study of 99 infants at a community hospital who were examined using indirect ophthalmoscopy and imaged using a non-contact retinal camera for retinopathy of prematurity. We evaluated the difference in the occurrence of safety events (i.e., clinically significant bradycardia, tachycardia, oxygen desaturation, or apnea) following the clinical examination versus retinal imaging. RESULT: Safety events occurred after 0.8% (n = 1) of imaging sessions and 5.8% (n = 18) of clinical examinations (mean difference = -0.055 (p = 0.015), favoring imaging). CONCLUSION: Retinal imaging with a non-contact camera was well tolerated and less stressful to infants compared to indirect ophthalmoscopy by an ophthalmologist.