Corneal Viscoelastic Properties in Patients With Angioid Streaks
Purpose
The aim of our study is to investigate the possible corneal biomechanical changes in patients with angiod streaks by using ocular response analyzer (ORA) and to understand if the calcified and thickened Bruch membrane that gives characteristic appearance to the fundus has overall influence on elasticity of the eye and intraocular pressure.
Methods
Twelve eyes of 12 patients with angioid streaks (6 males and 6 females) and 12 eyes of 12 age and sex matched healthy volunteers (6 males, 6 females) were enrolled in the study. Corneal hysteresis (CH), corneal resistance factor (CRF), corneal compensated intraocular pressure (IOPcc) and Goldmann correlated intraocular pressure (IOPg) were measured with ORA. Central corneal thickness (CCT) was measured with an ultrasound pachymeter.
Results
Mean CRF and IOPg values in eyes with angioid streaks (12.10±1.27, 17.76±2.73 respectively) were significantly higher than those in age-matched controls (10.70±1.28, 14.67±2.72 respectively) (p=0.01 for CRF, p=0.007 for IOPg). There was no statistical difference between patients with angioid streaks and healthy subjects in measured CH, IOPcc and CCT values (p=0.29, p=0.09, p=0.86).
Conclusion
This study revealed that angioid streaks affects corneal biomechanical properties by increasing CRF indicating that the structural, functional, and biomechanical properties of the cornea may be different in eyes with angioid streaks than in control eyes. Increased CRF means increased resistance for effect of IOP on eye so it might be speculated that these patients tend to be more protected for glaucoma.