CHANGES OF BIOMECHANICAL PROPERTIES OF THE CORNEAAFTER CATARACT PHACOEMULSIFICATION

Background: Cataract phacoemulsification is accompanied by changes in biomechanical parameters of the eye. Corneal hysteresis is a characteristic of viscoelastic properties of the cornea which may be studied in vivo. 

Aim: To assess the changes of corneal hysteresis in 3 months after phaco. 

Materials and methods: We studied 72  eyes of 72  patients after uncomplicated phacoemulsification with soft Intraocular lens implantation. Patients’ examination included routine assessment of corneal compensated intraocular pressure (IOP), Goldman-correlated IOP and corneal hysteresis using Ocular Response Analyzer (Reichert, USA) before the procedure, on the first 2 days, in 2 weeks,1 and 3 months after the procedure. 

Results: Corneal hysteresis decreased from 9.85 ± 0.30 mm Hg to 8.91 ±0.31 mm Hg on the first day after the procedure and to 7.97 ± 1.51 mm Hg (p < 0.05) after 2 weeks. Later, corneal hysteresis begins to grow and returned to preoperative values in 3 months after the procedure (9.68 ± 0.45 mm Hg). Directly after the procedure, IOP raised by 3–3.5 mm Hg, reached maximum in 2 weeks, then decreased to preoperative values in 1 month after phaco with consequent decrease by 1.5–2 mm Hg in 3 months after phacoemulsification. 

Conclusion: After phaco, decreased corneal hysteresis may reflect tissue response to the procedure. Return to reoperative values indicates recover of biomechanical properties of the cornea. Monitoring of corneal hysteresis may be useful for adequate clinical interpretation of the results of intraocular pressure measurement.