Micro-Aberrations Scattering Index (Masi) A Novel Parameter On Cso Osiris-T As A Predictor Of Visual Acuity And Contrast Sensitivity After Keratorefractive Laser Procedures

In literature, cases of slow recovery after keratoreffractive surgery have been reported, and there are indications that this could be attributed to the "orange peel" pattern. However, before making any evaluations we need to define an objective measure of this effect. There was a noticed difference in patients with "orange peel" pattern having a worse UCVA, CDVA and contrast sensitivity in the early post operative period. This was especially an issue in KLEx and was a key factor in KLEx being avoided by many LASIK doctors. We wanted to create an objective measurement system for this using an aberrometer from CSO to make comparison faster and easier. MASI is defined as Micro-Aberrations Scattering Index

Svjetlost Eye Clinic, Zagreb, Croatia

We measured MASI before and after surgery on POD1, POW1, POM1 and POM3, we also did a validated Sine wave contrast sensitivity test using Qvision Visual CSF test at each visit.

MASI was then compared for statistical significance against UCVA, CDVA and CS tests.

We performed measurements on 200 eyes, 100 KLEx, 50 LASIK and 50 PRK patients.

Primary end point was validation of MASI against an existing clinically validated test, secondary end point was to understand the effects of different doses in KLEx on visual recovery. MASI showed great correlation with expected UCVA, CDVA and contrast sensitivity. It help to objectively gage quality of vision during a simple scan that takes less than 10 seconds per eye versus a 8-10 minute per eye sine wave contrast sensitivity test. 

We strongly believe Micro-Aberrations Scattering Index will become the de facto standard for evaluating and simulating patient outcomes after keratorefractive procedures in high volume surgery centers where regular sine wave contrast sensitivity would be time consuming. This will allow us to objectively test different laser power settings and compare outcomes on an objective playing filed vs. pure reporting of UCVA and CDVA.