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ORA waveform analysis of biomechanical properties of the cornea in normal tension glaucoma and comparison with open angle glaucoma...

Session Details

Session Title: Cornea

Session Date/Time: Sunday 05/02/2012 | 08:30-11:00

Paper Time: 10:15

Venue: Hall 1

First Author: : A.Grise-Dulac FRANCE

Co Author(s): :    A. Saad   F. Cabot   J. Febbraro   D. Gatinel     

Abstract Details

"Purpose:

To analyze the Ocular Response Analyzer (ORA) waveform of biomechanical properties of the corneas in normal tension glaucoma (NTG) patients and compare them with those of patients with primary open angle glaucoma (POAG), isolated ocular hypertension (OHT) and normal subjects (N).

Setting:

Fondation Ophtalmologique Adolphe de Rothschild, Paris, France

Methods:

37 parameters of ORA waveform, caracterizing peak 1 and 2, were measured, among wich : area (p1 and p2area, p1and p2 area1), aspect ratio (aspect1, 2, 11 and 21), downslope (dslope1, 2, 11 and 21), width (w1 and w2), height (h1 and 2), dive (dive1 and 2) and absolute value of path length around each peak (path1 and 2). High frequency noise in region between peaks (aplhf) was also quantified. All parameters were provided by ORA device for 58 eyes of 29 patients with NTG, 85 eyes of 43 patients with chronic POAG, 57 eyes of 29 patients with OHT and 44 eyes of 22 N subjects. Ultrasonic central corneal thickness (CCT) was also measured for each eye. ANOVA test was used for statistical analysis. A p value lower than 0.05 was considered statistically significant. RESULTS CCT was not significantly different between the 4 groups. NTG subjects had significant lower aspect1, aspect11, dive1, dslope1, dslope11, h1 and h11 than normal subjects. POAG subjects had significant higher aspect11, w1 than normal subjects. NTG subjects had significant lower dive1, h1, h11, p1area, p1area1, p2area and p2area1 than POAG patients. Both POAG and NTG subjects had higher aplhf than normal subjects. OHT subjects waveforms were not significantly different from normal subjects except slight higher aplhf.

Conclusions:

NTG and POAG subjects were associated with significant differences on peak 1 and higher frequency noise (aplhf) compared to normal subjects. Peak 1 and 2 areas were significantly smaller in NTG group compared to POAG group. ORA waveform analysis could be useful in early diagnosis of NTG, OHT and POAG.

Financial Disclosure:

No"