Optimizing hand-held spectral domain optical coherence tomography imaging for neonates, infants, and children

Abstract

Purpose: To describe age-related considerations and methods to improve hand-held spectral domain optical coherence tomography (HH-SD OCT) imaging of eyes of neonates, infants, and children.

Methods: Based on calculated optical parameters for neonatal and infant eyes, individualized SD OCT scan parameters were developed for improved imaging in pediatric eyes. Forty-two subjects from 31 weeks postmenstrual age to 1.5 years were imaged with a portable HH-SD OCT system. Images were analyzed for quality, field of scan, magnification, and potential clinical utility.

Results: The axial length of the premature infant eye increases rapidly in a linear pattern during the neonatal period and slows progressively with age. Refractive error shifts from mild myopia in neonates to mild hyperopia in infants. These factors affect magnification and field of view of optical diagnostic tools applied to the infant eye. When SD OCT parameters were corrected based on age-related optical parameters, SD OCT image quality improved in young infants. The field of scan and ease of operation also improved, and the optic nerve, fovea, and posterior pole were successfully imaged in 74% and 87% of individual eye imaging sessions in the intensive care nursery and clinic, respectively. No adverse events were reported.

Conclusions: SD OCT in young children and neonates should be customized for the unique optical parameters of the infant eye. This customization, not only improves image quality, but also allows control of the density of the optical sampling directed onto the retina.

Figure 1.

Portable hand-held SD OCT workstation. (A) Arrow: reference arm position adjuster with digital readout. (B) Hand-held probe with focus adjustment system and diopter scale bar. Infant is imaged in the incubator with the non-contact probe held over the left eye. The lids are held open by the examiner's fingertips.

Figure 2.

(A) SD OCT scans of fovea in a premature infant without proper focus. Arrow: foveal area, blurred with low saturation in this image. (B) Good retinal layer differentiation in the SD OCT scan after fine focusing of the HH-SD OCT system.

Figure 3.

AXL change with age. (A) From 32 to 52 weeks PMA. (B) From birth to adulthood.

Figure 4.

SD OCT images with (A, B) and without (C–F) vignetting from incorrect reference arm length. (A, B) A 6.8 × 6.8-mm volumetric scan of a 38-week PMA infant obtained without reference arm correction, focus, or scan density correction. After reference arm correction, the 10.9 × 10.9-mm scan of a 35-week (C, D) and of a 47-week (E, F) PMA infant show a decrease in vignetting. The SVP demonstrates the loss of peripheral image in (A) compared with when the reference arm is correct (C, E).

Figure 5.

Retinal field of view and magnification with SD OCT in an infant. (A–C) The right eye at 8 months; (C) the projection of the SD OCT imaged area on the retinal camera photograph. (D, G) Additional SD OCT imaging of the same eye at 12 months. Left: the SVP retinal image with a selected B-scan in the middle column (corresponding to the green line in the SVP): (A, B) At high magnification, 6.8 × 6.8-mm scan projecting to 5.4 × 5.4-mm scan length on retina (80% of the adult); (D, E) with moderate magnification and wider field of view, a 10.9 × 10.9-mm scan projecting to 8.7 × 8.7-mm scan length on retina; and (F, G) with an even wider field of view, 13.6 × 13.6-mm volumetric scan projecting to 10.9 × 10.9-mm scan length (38°) on the retina. With SD OCT imaging of a large area, the scan area is limited by the pupil and vignetting occurs as in (F).

Figure 6.

Suggested sequence of steps for pediatric imaging with HH-SD OCT.