Stereo Scanning-Slit Tomography for Anterior Eye Examination

Abstract

Purpose : To present a compact scanning-slit tomography prototype for automated imaging of anterior eye disease and trauma.

Methods : The stereo scanning-slit tomography prototype was designed to produce images that could distinguish pathology in various layers of the cornea. A sharply focused narrow vertical slit of height 15mm and width 100µm of blue light scanned horizontally across the white-to-white corneal diameter. The slits were parallel to the optical axis of the eye and form a 3D cube of light-sheet illumination. Two cameras were located on both sides of the illumination axis at a skewed angle of 45 degrees to resolve the depth of imaged corneal and anterior eye pathology. The cameras were synchronized with the scan to record the slit position associated with each image frame. A hundred frames from each camera were acquired over 2 seconds.

Results : Figure 1 shows the device's potential for diagnosing corneal traumas. Common anterior eye trauma was simulated on ex-vivo porcine eyes using a scalpel. In particular, one half-thickness and one near full-thickness incision were performed around the corneal apex. Metallic particles were added to some incisions to imitate the presence of foreign bodies on the cornea. In addition, we performed corneal perforations close to the corneal limbus to imitate a cataract surgery.

Conclusions : Stereo slit-lamp tomography is an imaging modality that provides images of the cornea from different perspectives. Combining the acquired stereo pairs of frames enables depth-resolved visualization of the cornea. Furthermore, deep learning algorithms can be developed to improve the automatization for diagnosing anterior eye diseases and trauma.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.

 

Figure 1. Clinical applications of the stereo slit-lamp. a) Cornea of an ex-vivo porcine eye imaged by a microscope of magnification 10x. Lacerations were simulated by a scalpel; b) Punctate corneal abrasion as due to cornea dehydration; c) Partial thickness corneal laceration created by a scalpel; d) Metallic particle on the epithelium on both sides of a corneal laceration; e) Descemet's membrane detachment; f) Damage of the lens capsule .