Role of AS-OCT in Managing Corneal Disorders

Abstract

Optical coherence tomography (OCT) is analogous to ultrasound biometry in the cross sectional imaging of ocular tissues. Development of current devices with deeper penetration and higher resolution has made it popular tool in clinics for visualization of anterior segment structures. In this review, the authors discussed the application of AS-OCT for diagnosis and management of various corneal and ocular surface disorders. Further, recent developments in the application of the device for pediatric corneal disorders and extending the application of OCT angiography for anterior segment are introduced.

Keywords: AS-OCT; cornea; ocular surface.

Figure 1

(A) Clinical picture of OSSN in a 51-year-old male patient. (B) Corresponding AS-OCT image showing thickened and hyper-reflective epithelial layer (green arrow) with abrupt transition from normal to abnormal epithelium (white arrow).

Figure 2

(A–C) Clinical images of the left eye of a patient with limbal stem cell deficiency (LSCD) due to chronic sequelae of ocular chemical burns. (A) Slit lamp image depicting total limbal stem cell deficiency with a thick fibrotic pannus covering the visual axis. (B) Details of the anterior chamber can be hazily visualized in the superotemporal quadrant (pink arrow) in the infrared image of optical coherence tomography (AS-OCT) scan. (C) AS-OCT line scan showing the hyperreflective pannus (yellow arrows) with sufficient corneal stromal thickness to permit pannus dissection.

Figure 3

(A–F) This is a collage of images depicting recovery following simple limbal epithelial transplantation (SLET) in the patient from Figure 2. (A,B) Slit lamp image and the corresponding optical coherence tomography (OCT) image captured in the immediate postoperative period illustrating thinning of the corneal stroma with absence of the hyperreflective conjunctival epithelium. (C) The surface is well epithelialized, six weeks after SLET with stromal thinning evident on the OCT scan along with a normal hypo-reflective corneal epithelium (D) The stable ocular surface is maintained 5 months after the surgery (E,F).

Figure 4

Optical coherence tomography angiography of an eye with chemical injury illustrating lack of vasculature inferiorly (arrow), in the area with ischemia.

Figure 5

(A) Early postoperative AS-OCT scan shows a DMEK graft fold as indicated by blue arrow; (B) postoperative AS-OCT scan UT-DSAEK where is possible to evaluate graft thickness and profile.

Figure 6

Anterior segment optical coherence tomography images of various corneal conditions. Congenital hereditary endothelial dystrophy (CHED)—a thickened epithelial layer with underlying irregular bowman’s membrane, increased stromal thickness and abnormally thickened Descemet’s membrane (A); Hurler’s syndrome—a thickened corneal stromal layers and hyperreflective stroma (B); posterior polymorphous corneal dystrophy (PPCD)—abnormal thickening and hyperreflective Descemet’s membrane (C); Peters Anomaly—posterior corneal defect (D); and kerato-irido-lenticular contact (E).