Evaluation of patients with keratoplasty in Tanta University Hospital using anterior segment optical coherence tomography

Abstract

Purpose This study aimed to evaluate patients with keratoplasty in Tanta University Hospital using anterior segment optical coherence tomography (AS-OCT).Patients and methods This was a cross-sectional study that included 30 eyes of 22 patients who underwent keratoplasty in Tanta University Hospital from January 2016 till December 2016. The AS-OCT imaging using Topcon 3D optical coherence tomography; 3D OCT 2000(FA) was done. The preoperative pathology was corneal scarring in 16 (53.33%) eyes and advanced keratoconus in 14 (46.67%) eyes. Penetrating keratoplasty was done in 27 eyes, whereas deep anterior lamellar keratoplasty was performed in three eyes.Results Comparing the base line characteristics between the keratoconus and the corneal scar groups, statistically significant differences were detected in age (P<0.001), best corrected visual acuity (decimal) (P=0.001), spherical equivalent in diopters (D) (P=0.018), and thickness disparity at the wound interface (μm) (P=0.026). The keratoconus group was younger and had better best corrected visual acuity than the corneal scar group. The total number of graft–host interface images from 30 eyes obtained by the AS-OCT was 120 cross sections. Of these, 22 (18.33%) cross sections had well-apposed junction and 98 cross sections had malapposed junction (81.67%). Protrusion (50 cross sections; 41.67%) was the most frequent misalignment type. When classifying the eyes according to the most frequent alignment pattern among the four cross sections, five eyes had well-apposed junction state (16.67%) (all were keratoconus cases) and 25 eyes had the malapposed junction state (83.33%) (corneal scar: 16 eyes, keratoconus: nine eyes). Among the 25 eyes with malapposed junction state, 12 eyes had protrusion, seven eyes had gap, and six eyes had step.Conclusion The AS-OCT is a valuable tool for postoperative follow up of patients with keratoplasty. It helps in visualization of the internal surface of the graft–host interface. Thus, it can help in detecting the malapposition and so the cause of postoperative astigmatism can be recognized and can be managed early.