Comparison of ultrasonic and ophthalmoscopic evaluation of retinopathy of prematurity

Abstract

Purpose: Screening for detection of retinopathy of prematurity (ROP) currently is limited to indirect ophthalmoscopy, which requires considerable examiner skill and experience. We investigated whether conventional 10 MHz B-scan ultrasonography could document the clinical stages of ROP as accurately as indirect ophthalmoscopy.

Methods: Thirty-four eyes of 18 neonates were examined by masked, independent observers with indirect ophthalmoscopy and digitally recorded 10-MHz B-scan ultrasonography. After pupil dilation and lid speculum placement, the retinologist recorded the stage of retinopathy with a retinal drawing. The ultrasonographer, without use of papillary mydriatics or lid speculum, determined the presence or absence of a ridge or tractional elements, if present on the ridge.

Results: Ultrasound grade correlated with clinical grade (R = .79, P < .001). However, nine eyes were overdiagnosed by one stage, and one eye, in which a peripheral detachment was mistaken for an artifact, was underdiagnosed.

Conclusions: Ten-megahertz ultrasonography offers the potential of imaging and detecting the clinical stages of ROP; the use of higher ultrasound frequencies, now becoming commercially available, is likely to enhance diagnostic accuracy. Care must be taken to distinguish between artifact and true anatomical structures in noncontact ultrasound examinations. Neonates with suspected ROP could be screened with B-scan ultrasonography by neonatal personnel without pupillary dilatation or lid speculum, thus eliminating potential morbidity, and clinically significant cases of ROP then could be referred to the retinologist.

Figures

Figure 1

Cribside examination of the eye with ultrasound. Enclosure of the transducer probe in a fluid-filled sheath ensures sterility and allows optimal positioning of the transducer focal zone.

Figure 2

(A) Ultrasonic view of an eye with stage 2 retinopathy of prematurity (ROP). The arrows point to a ridge, which exhibits increased echogenicity. (B) Ultrasonic view of a peripheral detached retina (arrows) in the region of a ridge in stage 4 ROP.

Figure 3

Histogram representing comparative ultrasound and clinical classification of all eyes.