The Bascom Palmer Eye Institute Pediatric OCT System: A Concept

Abstract

Purpose: : To design, develop and fabricate a system to perform Optical Coherence Tomography (OCT) on sedated premature infants in order to study and evaluate the macula and retinal nerve fiber layer of premature eyes.

Methods: : A pediatric OCT system was created by modifying a Stratus Zeiss–Humphrey OCT–3 with a custom built adjustable stage and infant carrier with 2 axis of rotation to allow examination of the retinal structures of premature infants. To effectively visualize the fundus, all infants are anesthetized in the controlled environment of the Bascom Palmer Eye Institute Anne Bates Leach Eye Hospital's operating suites. Each infant is monitored in the presence of an experienced ophthalmologist and pediatric anesthesiologist. The custom made infant carrier is designed with safety in mind and to allow easy access to the child in the face of an emergency. The carrier is designed to safely accept children up to age 3 and weighing no more than 45 pounds. The OCT–3 is used to obtain cross–sectional images of macula and retinal nerve fiber layer.

Results: : Engineering designs were made using 3–D CAD software (SolidWorks Corp Concord, MA) and anthropometric data of infants (www.itl.nist.gov), to define 3 cradles for preemies, babies 1 year or less, and children age 1 to 3. A 3–section bead–filled vacuum bag mechanism was designed to hold the infant without compression to the head, thoracic cage, abdomen, arms and legs, yet leaving space for positioning tracheal tube, EKG leads, pulse, pressure monitoring cuff and IV lines. The system easily allows proper vertebral column and head positioning to free the air–way and prevent tracheal tube motion. Safety mechanisms include a magnetic lock to the table and Velcro straps. A battery operated vacuum pump located beneath the support table assures fixation of the infant is less than 15±5s and release in less than 5±2s. A first generation designed for preemies was tested using a manikin. The support system and OCT functions were tested in a rabbit model. A second generation for use on human infants is under construction.

Conclusions: : The pediatric OCT imaging system is an innovative concept that may be a useful tool to evaluate the structural abnormalities of the macula and retinal nerve fiber layer associated with infant prematurity.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • infant vision • retina