Biomechanical Properties of Corneal and Ocular Aberrations in Myopic Eyes

Saturday, April 18, 2015: 1:06 PM
Room 1B (San Diego Convention Center)
Rebika Dhiman, MD
Shiva P. Gantyala Jr., MD
Divya Singh, MD
Murugesan Vanathi, MD
Radhika Tandon, MD, FRCS, FRCOphth

To study the correlation of corneal biomechanical properties and ocular aberrations with the magnitude of the refractive error in myopic eyes.

Observational study of 30 myopic patients (60eyes) attending clinic for refractive surgery, categorized into group 1–suitable for femto-LASIK, and group 2– not suitable for femto-LASIK. Data recorded included visual acuity -uncorrected & best corrected, axial length(AL), central corneal thickness(CCT), manifest refraction spherical equivalent(MRSE), anterior corneal curvature (Ka), posterior corneal elevation (PE) [Pentacam–Oculus], corneal biomechanical factors [corneal hysteresis(CH), corneal resistance factor (CRF), Goldmann-correlated intraocular pressure (IOPg), corneal-compensated IOP (IOPcc) [Ocular Response Analyzer (ORA)], optical aberrations –higher-order (HOA) and lower order (LOA) (iTrace).

Ongoing study, results of 60 eyes presented here. Results will be updated. The mean values (±SD) in group 1 (n = 38) and group 2 (n = 22) for MRSE, AL, CCT, Ka, PE, CH, CRF, IOPg, IOPcc, HOA, LOA respectively were-4.61D (±2.4D)/-9.41D (±4.18D) [p = 0.00], 23.95 (±1.38)/26.49mm (±1.29) [p=0 .023], 531 (±39)/493µm (±28.99) [p = 0.027], 43.66 (±1.58)/43.79 (±2.12) [p=0.037], 12.38 (±5.70)/16.13µm (±10.84) [p=0.506], 9.87 (±2.03)/9.13mm Hg (±1.58) [p = 0.825], 9.57 (±2.13)/ 8.62mm Hg (±1.78) [p = 0.560], 14.01 (±3.08)/13.30mm Hg (±2.91) [p = 0.884], 15.67 (±2.75)/15.66mm Hg (±3.04) [p = 0.544], 0.2153 (±0.16)/0.2148 (±0.13) [p = 0.670] and 3.389 (±1.60)/4.086 (±2.15)[p=0.218] respectively.

The factors like amount of refractive error, axial length, central corneal thickness and anterior corneal elevation do significantly vary in the candidates suitable versus those who are unsuitable for LASIK in contrast to other factors like the biomechanical properties of the cornea and ocular aberrations which were not significantly correlated.