How can measurement of axial length be useful in the management of keratoconus by intra-corneal ring segment implantation?
First Author: Y.Rifay MOROCCO
To studiy the interest of eye axial lenth mesurement in the planning for intra corneal ring segment implantation in keratoconus.. Refraction in ectatic diseases is very difficult that make the sphere calculation very inaccurate . The mesurement of axial lenth can give roughly the amouth of sphere that can help for therapeutic surgical plan.
This is a retrospective study in 167 keratoconic eyes that have been treated by intra corneal ring segment implantation without using manufacturer’s nomograms.
Calculation of the ring used Uncorrected visual acuity, Best corrected distance visual acuity , potential visual acuity with hard contact lens, corneal tomography, subjective non cycloplegic refraction and axial lenth mesurement by a non contact biometer. Surgery was done under topical anesthesia in 165 eyes and general anesthesia in 2 eyes, all surgeries were done by femto second laser tunnel creation , ring used were Keraring.
In the 167 studies eyes , 13 eyes were high myopes with axial lenth more than 25 mm, 23 eyes were moderately myopes with Axial lenth between 23 and 25 mm, and 131 were emetropic. 16 eyes were treated with intra corneal rings and phakic IOLs, and 151 were treated only with intra corneal ring implantation. Mean preoperative BCVA is 0.27, and mean BCVA is 0.69.
The use of axial lenth measurement is a very interesting tool for sphere evaluation to plan for intra corneal ring segment implantation in keratoconic eyes, it gives an idea about the amount of sphere to diferenciate between real axial high myopia and false myopia due to errors in the evaluation of refraction in keratoconic patients.