Abstract
Purpose: :
Corneal and scleral melts pose diagnostic and surgical challenges to clinicians. Affected tissues are often brittle, opaque, and poorly visualized by slit lamp biomicroscopy. This report presents anterior chamber optical coherence tomography (OCT) as a novel method for safely assessing corneal and scleral melts pre–operatively and evaluating post–operative membrane graft integrity.
Methods: :
Two patients undergoing three membrane graft repairs were studied. The first patient presented with a corneal melt and the second with a scleral melt. Both patients were treated with membrane grafts. Slit lamp photography and anterior segment OCT were performed at the initial visit and during a series of postoperative visits. The Zeiss prototype Cornea Anterior Segment OCT (CAS–OCT) system was used to image the anterior segment. The model acquires 2000 axial scans/second using 1300 nm wavelength light to produce axial and transverse resolutions of 17 and 45 µ respectively full–width half maximum (FHWM) in tissue.
Results: :
A 32 year old female with Crohn’s disease peripheral ulcerative keratitis presented with 5’/200 visual acuity and 360 degree corneal ulceration with limbal conjunctival ingrowth. An amniotic membrane graft was performed. OCT showed apposition of the graft and native cornea on post–op day 1 and full integration one week and two months later. A 65 year old male presented with a 2 x 2 mm nasal scleral melt with overlying opaque plaque associated with beta irradiation. The vertical OCT scan showed 60–70% thinning and suggested the plaque was composed of calcium. The horizontal scan showed the lesion’s relation to the sclera, ciliary body, and muscles. An epicardium amniotic membrane graft with Tisseal fibrin glue was performed without complication, and OCT 1 week post–operatively shows both layers to be in place. One month later, the scleral patch detached from the graft site and was lost. A fresh corneal lamellar graft and pedicled conjunctival rotational autograft secured by sutures were performed with good results.
Conclusions: :
Anterior segment OCT is a fast, reproducible, non–contact, technology that can aid the clinician in evaluating and repairing corneal and scleral melts. The 1300 nm wavelength light penetrates opaque tissues well. OCT is useful in assessing corneal and scleral thinning and identifying whether tissues deep to the ocular surface are affected. Postoperatively, OCT can be used to assess the position and depth of the graft membrane.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • cornea: clinical science • autoimmune disease