Purpose
To describe and evaluate the results of a novel technique, utilizing spectral domain anterior segment optical coherence tomography (SD-AS-OCT), to define the volume of corneal lesions.
Methods
Three patients with post-LASIK epithelial ingrowth, inactive herpes simplex stromal keratitis and vascularized herpes zoster stromal keratitis at Moorfield Eye Hospital were investigated with SD-AS-OCT (Spectralis, Heidelberg Engineering, Heidelberg, Germany). Anatomical layers of cornea (including epithelium, stroma, Descemet's membrane and endothelium), LASIK flap interface and lesions within corneal substance were manually delineated by custom image analysis software. Colour photographs were correlated with OCT findings.
Results
Different patterns of corneal lesions were revealed by SD-AS-OCT and the imaging allowed measurement of lesion size to be undertaken. Post-LASIK epithelial ingrowth was observed as sharply delineated hyperreflective lesions with surrounding oedematous corneal tissue at the flap interface, and reduced local epithelium thickness. Mean lesion height was 64.3μm, and volume 0.71mm3. Herpes simplex stromal keratitis appeared as a poorly defined, confluent lesion within the stroma, with a mean lesion height of 76.8μm and volume of 0.54mm3. In Herpes zoster corneal vascularization, hyperreflective linear scarring distorts the overlying Bowman's membrane, with a mean lesion height of 15.8μm and volume of 0.17mm3. In addition, corneal vessels adjacent and within the lesion could be detected on SD-AS-OCT images.
Conclusions
Quantitative measurements of lesion volume is a novel method to describe corneal lesions, and may be a useful tool in the management of other corneal disease.
Keywords: 550 imaging/image analysis: clinical •
479 cornea: clinical science