Abstract
Purpose:
The purpose of the present research was to analyze the influence of biomechanical properties of fibrous coat of the eye on intraocular pressure (IOP) in patients after intravitreal ranibizumab injections.
Methods:
The study involved 60 patients (60 eyes) with wet age-related macular degeneration without history of glaucoma or ocular hypertension. 0,05 ml (0,5 mg) of ranibizumab was injected into the vitreous. IOP was measured before and 1 minute after the injection with the Icare ONE tonometer (Finland). Biomechanical properties of the cornea such as corneal hysteresis (CH) and corneal resistance factor (CRF) were examined two weeks after the last injection (after IOP normalization without medication) with an Ocular Response Analyzer (Reichert ORA, USA).
Results:
One minute after injection IOP in all patients was elevated by 14,0±0,39 to 36,9±1,5 mm Hg. In 7 patients IOP after injection was more than 35 mm Hg, CH and CRF in these eyes were 7,25±0,33 and 10,2±0,7 respectively. In 5 other patients IOP after injection was less than 15 mm Hg, CH and CRF were 9,88±0,33 and 9,9±0,66 respectively. Difference in CH was statistically significant (p=0,021).
Conclusions:
Viscoelastic property of fibrous coat of the eye is characterized by CH. Lower CH determines elevated IOP after intravitreal ranibizumab injection.
Keywords: 412 age-related macular degeneration •
479 cornea: clinical science •
568 intraocular pressure