Topographic effect persistence after intracorneal ring segment explant: densitometric evaluation
First Author: M.Molero Senosiain SPAIN
Co Author(s): J. Garcia Bella R. Cuiña Sardiña D. Diaz Valle P. Arriola Villalobos .
Our pourpose is to show the topographic effect persistence of an intracorneal ring segment (ICRS) after its explant due to extrusion in Keratoconus.
It has been observed that GSU is higher in advanced keratoconus stages and increases after a 1 to 4 year follow-up period in patients who have been treated with CXL, compared to preoperative measures
With the Pentacam HR software the density is calculated using a gray scale (gray scale unit –GSU) to measure the light scattering, being 0 the maximum and 100 the minimum transparency. The analysis of the central 12mm diameter of the cornea is performed in concentric rings from 0to12mm. Depth is also considered as anterior, mid stroma and posterior layer. GSU (grey scale for density) is higher in advanced keratoconus stages and increases after 1to4 year follow-up in patients who have received CXL, compared to preoperative measures. Some studies have shown that corneal density is not significatively modified after ICRS implantation.
The data we observed in our patient (from 17.3 to 16.9 GSU/m3) would suggest the possible effect of the modification of the collagen fibers after the implantation of the ICRS and the remodeling of the corneal stroma, generating an increase in density due to the fibrosis produced, coinciding with the most curved area of the cornea and producing a flattening.
In conclusion, this case shows that ICRS implantation is not a completely reversible technique, so proper information should be given to the patients regarding this procedure. Longer studies, including topographic and densitometric evaluations after ICRS explantation, are needed to confirm this observation.