A definitive evidence of corneal stiffening in keratoconus eyes from polarisation sensitive OCT imaging
First Author: P.Paritekar INDIA
Co Author(s): P. Khamar R. Patil R. Shetty A. Sinha Roy
To study the binding of collagen fibril structures on crosslinking eyes using custom built ultrahigh resolution polarization sensitive (PS) – OCT.
Study was conducted on 30 eyes in an eye institute after prior institutional ethics committee approval. It was a progressive, observational study.
30 progressing eyes with varying grades of KC were imaged preoperatively and postoperatively at 1 week, 1 month, 3 months and 6 months with PS-OCT. A scan field of 11mm diameter was achieved using conical scan setup enabling uniform signal strength throughout the cornea. Enface maps representing corneal fibril distribution based on polarization sensitive information were generated using phase retardation and axis orientation information from the posterior cornea. To ensure repeatability all eyes were imaged at least 3 times.
Preoperative enface maps of KC eyes showed an abrupt change in preferential arrangement of collagen fibril structures. Binding of collagen fibrils appeared to be weak in KC eyes. This weak binding of collagen fibrils strengthened from 3 months post crosslinking and in some cases stabilized at 6 months with a relatively stronger binding as compared to respective preoperative arrangements.
The binding density of collagen fibrils was observed to improve and strengthen with time, postoperatively after crosslinking. Posterior corneal surface enface maps derived from PS-OCT can be used to track changes in collagen fibril structure arrangements aiding in analysing the effect of crosslinking procedure.