THE ROLE OF OCT IN THE FOLLOW UP EVALUATION OF PENETRANTING KERATOPLASTY

To investigate cornea vascularization (CNV) in eyes with penetranting keratoplasty using optical coherence tomography angiography (OCTA) technology

Prospective cross-sectional study of vessel density (VD) measurements in patients submitted to penetrating keratoplasty at least 5 years, without history of rejection. 20 eyes of 18 patients were included. All eyes underwent anterior segment Slit-Lamp photography (SLP), and OCTA with en-face, b-scans and c-scans imaging. The VD was analyzed in the inferior, nasal and temporal corneal margin in all patients. The measurements were calculated after binarization with ImageJ software, using OCTA scans with 6x6 mm in a depth of 800 μm.

Patients included had a mean age 59.278±18.689 (years±SD). The mean cell density (CD) was 1399.894±340.390 and the mean central corneal thickness (CCT) was 576.4±62.02. The mean total vessel area was 50.159±2.521%. VD was higher in the temporal quadrant (50.470±2.440) and lower in the inferior quadrant (49.987±2.468) but there were no significant differences between the three analyzed areas (p=0.801). OCTA was able to identify abnormal vessels when SLP apparently showed no abnormal vessels; OCTA was able to distinguish between larger and smaller vessels; OCTA scans allowed the investigation of several corneal planes and the relation of them with clinical findings.

OCTA can be useful in both qualitative and quantitative follow-up of eyes with penetranting keratoplasty. It is well known that graft failure and rejection risk progressively increase as an increasing number of quadrants of the eye are affected with pathologic corneal neovascularization. Besides this it is know that penetrating keratoplasty promotes parallel growth vessels into the avascular recipient bed. OCTA is a non-invasive alternative to objectively monitor corneal vascularization