Optical coherence tomography (OCT) is a means of noninvasive evaluation of the retina and optic nerve through imaging the back of the eye. The extension of this capability to the front of the eye rounds out our ability to provide a complete, noninvasive evaluation of the eye. Image types include corneal, angle and sclera.
Corneal scans allow for assessment of corneal thickness (CT) and low-resolution imaging of corneal cells. This noninvasive technique allows for CT monitoring over the duration of a safety assessment study. Measurements are taken prior to the initiation of dosing and, at a minimum, following cessation of dosing.
By imaging the iridocorneal angle, changes in the angle can be monitored over the duration of a safety assessment study. Spectral-domain OCT (SD-OCT) provides the capability for noninvasive imaging of anterior segment ocular structures. This technique is particularly suited to topical ocular toxicology studies, but is also applicable to the evaluation of nonocular therapeutics, which have been shown to cause ocular effects. The Heidelberg Spectralis® can obtain images from many of the commonly used laboratory animal species. In addition to anterior segment SD-OCT, posterior segment structures such as the retina and optic nerve can be imaged.
Scleral imaging provides the ability to monitor the appearance and volume of the sclera, as well as to monitor sclera blebs, if present.
The scanning laser ophthalmoscopy component of the anterior segment OCT provides an image of the cornea, iris and pupil that may also be useful for monitoring changes over the duration of an ocular toxicity study.
Together, these capabilities can be applied to studies for front-of-the-eye therapeutics targeting diseases such as glaucoma and uveitis.