New parameters for evaluating corneal biomechanics and intraocular pressure after small-incision lenticule extraction by Scheimpflug-based dynamic tonometry

Abstract

The biomechanically corrected IOP measured after surgery with the dynamic Scheimpflug analyzer showed better agreement with the preoperative values than IOP. The stiffness parameter was not dependent on the amount of removed corneal thickness. A new sign correlated with dynamic corneal densitometry was found and might be related to changes in corneal hydration and biomechanics.

Age Distribution and Associated Factors of Cornea Biochemical Parameter Stress-Strain Index in Chinese Healthy Population

“…It was not surprising, since SSI re ected the corneal stiffness, and IOP measurement was affected by corneal stiffness 10,34 . While it was emphasized that bIOP can exclude the in uence of corneal thickness and age on intraocular pressure measurement 35 , and can re ect more accurate intraocular pressure [36][37][38] . Besides IOP, previous studies have shown that, parameters of corneal biomechanics in vivo were mostly affected by bIOP such as de ection area at the highest concavity and de ection amplitude (HC DefArea and HC DefA), SP -A1 38 CH and CRF 39 .…”

Biomechanical changes in the cornea following cataract surgery: A prospective assessment with the Corneal Visualisation Scheimpflug Technology

“…However, only A1 deflection length was significantly between control eyes and eyes having laser in situ keratomileusis (LASIK), femtosecond lenticule extraction or small‐incision lenticule extraction in another study . There is ongoing debate about the changes in corneal biomechanical properties with LASIK compared to small‐incision lenticule extraction (SMILE) . The A1 stiffness parameter changes independently of the lenticule thickness in SMILE surgery and corneal refractive surgery, in contrast to other dynamic corneal response factors, which correlated highly with lenticule thickness …”

“…There is ongoing debate about the changes in corneal biomechanical properties with LASIK compared to small‐incision lenticule extraction (SMILE) . The A1 stiffness parameter changes independently of the lenticule thickness in SMILE surgery and corneal refractive surgery, in contrast to other dynamic corneal response factors, which correlated highly with lenticule thickness …”

“…29 There is ongoing debate about the changes in corneal biomechanical properties with LASIK compared to small-incision lenticule extraction (SMILE). [30][31][32] The A1 stiffness parameter changes The analysis accounts for non-linear confounding effects of intraocular pressure, corneal thickness, age and gender. Abbreviations: A1, first applanation; A2, second applanation.…”

“…independently of the lenticule thickness in SMILE surgery and corneal refractive surgery, in contrast to other dynamic corneal response factors, which correlated highly with lenticule thickness. 32 Corneal stiffness is reduced following cataract surgery causing corneas to reach A1 faster with greater total deformation and higher outward velocity at A2. The decrease in corneal stiffness is, however, partially confounded by the decreased postoperative IOP and vice versa as these parameters cannot be independently measured using the Corvis-ST. 12 Multiple linear regression and generalized linear model analysis was used in the current study to overcome this limitation and definitively identify those factors that relate directly to corneal biomechanical changes independent of IOP.…”