Corneal Curvature Ratio To Help Improve Lens Calculation Accuracy After Laser Vision Correction Surgery
Published 2022
- 40th Congress of the ESCRS
Reference: PP13.05
| Type: ESCRS 2022 - Posters
| DOI:
10.82333/jy1r-a498
Authors:
Ben Lahood* 1
, Michael Goggin 1
, Doug Koch 2
, Li Wang 2
1Ophthalmology,The Queen Elizabeth Hospital,Adelaide,Australia, 2Ophthalmology,Baylor University,Houston,United States
Purpose
Calculating the correct intraocular lens (IOL) power for an eye post laser vision correction (LVC) is less precise than for standard eyes. Total keratometry (TK) and modern formulas have improved our predictions. However, eyes which have either shown regression following LVC, or underwent multiple refractive procedures, as well as those eyes where the patient has forgotten their pre-LVC refractive error can still be challenging. This study aimed to assess whether using the ratio of posterior to anterior corneal curvature could help guide appropriate IOL calculation methods and improve refractive outcomes.
Setting
Private Practice at Ashford Advanced Eye Care in Adelaide, Australia
Methods
53 consecutive eyes that underwent cataract surgery post LVC were included. All had a complete set of pre-operative biometry including anterior and posterior keratometry as well as corneal tomography. An additional four eyes had undergone multiple keratorefractive procedures prior to cataract surgery. 6 weeks post-operatively, an accurate subjective refraction was obtained to provide an ideal calculated IOL. Corneal curvature ratios were used to categorise eyes into either non-LVC, previous myopic, or previous hyperopic treatments and IOLs calculated accordingly. These values were compared to ideal IOL power and those calculated based on the patient history of LVC type.
Results
17 eyes of 53 (32%) had corneal curvature ratios indicating a category of LVC different to their history, of which 13 (76.5%) had a difference in IOL power recommended by the Barrett Universal Formula. 14 eyes had corneal curvature ratios indicating no prior LVC while 3 eyes had a history of myopic LASIK but had corneal curvature ratios indicating previous hyperopic keratorefractive ablations. Of the 13 eyes where a difference in IOL power was recommended, the IOL based on curvature ratio rather than history would have given a better refractive outcome in 10 cases. All four eyes that underwent multiple keratorefractive procedures had improved outcomes when IOL power was calculated based on corneal curvature ratio.
Conclusions
Corneal curvature ratio appears to be helpful in identifying the most precise method to calculate IOL power following LVC. This is especially useful in eyes that have undergone multiple refractive procedures. Consider using this method for all eyes where regression is suspected or where corneal tomography does not clearly indicate a typical identifiable LVC pattern.