Use of the novel polarisation sensitive (PS) OCT to image and analyse the changes in the structural arrangement of collagen fibrils post cataract surgery
First Author: N.Balakrishnan INDIA
Co Author(s): L. Kaweri R. Shetty R. Patil Y. Patel A. Roy
To analyse changes in collagen fibril structures post cataract surgery using custom built ultrahigh resolution polarization sensitive (PS) – OCT and to see its effect on surgically induced astigmatism (SIA).
Narayana Nethralaya Super Speciality Hospital
In this longitudinal case study, 30 eyes that underwent micro-incision cataract surgery were imaged preoperatively and postoperatively at 1 week, 1 month and 3 months with PS-OCT, Pentacam HR and Lenstar LS900. A scan field of 11mm diameter was achieved using conical scan setup enabling uniform signal strength throughout the cornea. Phase retardation and axis orientation enface maps were generated at the posterior corneal surface, to see changes in collagen fibril arrangement. Further, to ensure repeatability all eyes were imaged at least 3 times at the incision site.
Phase retardation and axis orientation enface maps showed changes in the preferential arrangement of collagen fibrils post cataract surgery in the cornea and at the incision site. The crimping effect of the fibrils due to incision, was observed as distinct changes in the sectoral alignment of collagen fibrils in the axis orientation maps and at the site of incision. Postoperative SIA was correlated to the level of crimping of the fibrils.
PS-OCT showed changes in the birefringence properties of the cornea and incision post cataract surgery. This may be used to monitor acute wound healing and more reliable prediction of SIA.