Abstract
Purpose: :
Evaluate the Ocular Response Analyzer (ORA), and study corneal hysteresis according to age, in three groups : glaucoma, intraocular hypertension and normal. Compare intraocular pressure (IOP) measures with ORA, Goldman tonometer (IOP Goldmann) and air-puff applanation tonometer (IOP air).
Methods: :
Prospective, single center study including 329 eyes, distributed in Normal (n=207), Intraocular hypertension (n=55) and Primary Open Angle Glaucome (n=67). For all patients, ORA provide Corneal Hysteresis (CH), Goldmann correlated IOP (IOPg) and corneal-compensated IOP (IOPcc) measurements. Ultrasonic Central Corneal Thickness (CCT US), IOP measured with Goldmann and air-puff tonometers were also assessed for each eye.
Results: :
Mean values are : IOP Goldmann 14.4 ±3.4 mmHg, IOPair 15.5±3.6 mmHg, CCT 542.1±3.6µm, CH 10±1,7 mmHg, IOPcc 16.6±4,1 mmHg and IOPg 15.7±3.9 mmHg. The four IOP measurements are strongly correlated in the three age groups. Mean CH in glaucoma (9.8 mmHg) and intraocular hypertension (9.6 mmHg) groups are lower than in the normal group (10,3 mmHg), but an age-related analysis of the three groups found no significant difference. CH and CCT US are correlated in the three groups. IOP measures are not strongly correlated with CH except for IOPcc. There is a negative correlation (-0.79) between CH and IOPcc.
Conclusions: :
Mean ORA, CCT US and IOP values in the Normal group are similar to those found in others publications. These are the first CH values reported for a normal group according to age. We confirm the good correlation between all IOP measurements. The mean Corneal Hysteresis value was low in glaucoma an ocular hypertension, but there is no difference between the three groups for CH values when groups are analyzed according to age. There is a correlation between corneal hysteresis and corneal central thickness. Moreover, IOPcc seems to be the best evaluation of IOP with no influence of corneal biomechanical factors. The Ocular Response Analyzer provide usefull measurements for follow up of patients with intraocular hypertension or glaucoma.
Keywords: intraocular pressure • cornea: clinical science