Abstract
Purpose: :
To elucidate the sub-clinical anatomy of retinopathy of prematurity (ROP) using spectral domain optical coherence tomography (SDOCT).
Methods: :
Three neonatal subjects, ages 23-37 weeks post menstrual age (PMA) were studied with parental consent for this IRB-approved study. Clinical examination was performed using a portable slit lamp and indirect ophthalmoscope. An SDOCT imaging system with a hand-held probe (Bioptigen Inc., Research Triangle Park, North Carolina) and Retcam (Clarity Medical Systems, Pleasanton, California) or video-indirect recording was used for imaging. Imaging was performed in the supine position at the bedside in the neonatal intensive care unit (NICU) and in the operating room. SDOCT images were acquired using Invivovue 1.1 software (Bioptigen Inc., Research Triangle Park, North Carolina). Pre-retinal structures observed on the cross- sectional SDOCT scans were manually traced using the ImageJ software (National Institute of Health, Bethesda, Maryland), and 3-D videos and still images were created using AMIRA version 4.1 software (Visage Imaging Inc., Carlsbad, California). Retcam, video-indirect images and clinical exam notes were compared to SDOCT images.
Results: :
SDOCT images revealed pre-retinal structures, retinoschisis, epiretinal membranes , vitreo-macular traction and retinal detachment in the posterior pole of patients with advanced ROP. Many of these findings were not identified on conventional examination or imaging by the pediatric ophthalmologists or retinal surgeon. The pre-retinal structures extended over the optic nerve and in numerous sites in zone I and II. Some of these structures were found in close proximity to blood vessels. They ranged in size, from 409 microns to 2.7 mm (lateral dimension) and 212 to 440 microns (height). Each subject demonstrated retinoschisis in the inner layers of the retina, not appreciated on clinical examination.
Conclusions: :
Hand-held SDOCT imaging can be performed on the supine non-sedated neonate and provides valuable sub-clinical anatomic information. This novel imaging modality can reveal the location and extent of posterior ROP pathology not evident on conventional examination.We hypothesize that these pretinal structures represent pre-retinal neovascularization. Although this study encompasses very few subjects and further research is clearly needed, we speculate that SDOCT imaging has the potential to play a meaningful role in evaluation of severe ROP.
Keywords: retinopathy of prematurity • imaging/image analysis: clinical • visual development: infancy and childhood