Assessment of Human Corneal Biomechanical Properties After Refractive Surgery With Inflation Test Using Optical Coherence Tomography.

PURPOSE: To evaluate the biomechanical properties of the cornea after refractive surgery using an inflation test combined with optical coherence tomography (OCT).

METHODS

Nine human donor corneas were divided into two groups: healthy (control) and treated (divided into three subgroups: photorefractive keratectomy [PRK], laser in situ keratomileusis [LASIK], and small incision lenticule extraction). Refractive treatments were applied to simulate -4.00 diopters of myopia correction. The corneas were mounted on an artificial anterior chamber, and an inflation test was performed using a custom set-up. Intraocular pressure was increased from 15 to 120 mm Hg in steps of 15 mm Hg, and corneal deformation was monitored via OCT imaging. The apex displacement versus IOP relationship was analyzed to calculate corneal stiffness, expressed as Young's modulus. Corneal thickness and curvature were also measured. Statistical comparisons were performed between healthy and treated corneas.

RESULTS

All treated corneas exhibited significant reductions in thickness and Young's modulus compared to the healthy group. The mean corneal thickness was 552.0 ± 5.9 µm in the healthy group and 486.9 ± 14.0 µm in the treated group (P < .05). Young's modulus was significantly lower in treated corneas (14.2 ± 4.9 MPa) compared to healthy corneas (22.9 ± 0.5 MPa, P = .02). Among surgical techniques, LASIK resulted in the greatest reduction in corneal stiffness, whereas PRK showed the least impact.

CONCLUSIONS

Inflation testing combined with OCT imaging allows for precise assessment of biomechanical alterations following refractive surgery. These findings highlight the importance of considering biomechanical consequences when selecting refractive procedures.