Sympathetic effect of cross-linking in the unoperated contralateral eye post cross-linking – a molecular and clinical profile
First Author: P.Khamar INDIA
Co Author(s): R. Shetty A. Ghosh S. Sethu
Collagen cross-linking (CXL) is now a standard of care to arrest progressive keratoconus (KC) in patients. There have been anecdotal reports regarding stabilization of KC in the unCXLed contralateral eye in clinical practice. Hence, in this study we investigated the clinical and molecular changes in the unCXLed contralateral eye following CXL in the ipsilateral/other eye in KC patients.
Narayana Nethralaya, India
The study was approved by institutional review board and patients were recruited following informed consent. KC diagnosis was based on clinical parameters including visual acuity, topographical features and structural deformity. Serial topographical maps based changes in Kmax upon patient follow- ups were used to determine progressive form of the disease.Tear fluid using schirmer’s strips was collected from both the eyes of the study subjects (n=65;130 eyes) prior to CXL and 6 months post CXL.30 tear soluble factors including cytokines, chemokines, cell adhesion molecules, growth factors and extracellular matrix remodellers were measured by bead-based multiplex ELISA using a flow cytometer.
A significant (P<0.05) reduction in the Kmax between pre-op and follow up visit was observed in the CXL eye. No changes or increase in the Kmax was observed in the contralateral unCXLed eye between the visits suggestive of stabilization of KC. Further, reduction in the tear soluble factors including IL- 1, IL-6, IL-17, IL-18, IL-33, NGAL, β2microglobulin, MMP2, MMP9 was observed between the pre- and post-op visits in most of unCXLed contralateral eye.
Trends towards reduction in clinical progression of KC along with reduction in key tear inflammatory factors and extracellular matrix remodellers were observed in the unCXLed contralateral eye between pre-op and follow up visits in KC subjects. This suggests the plausibility of a beneficial sympathetic effect in the unmanaged KC eye CXL in the contralateral eye, but further studies are needed to establish why it works only in certain cases.