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Evaluation of the role of corneal hysteresis in diagnosis of glaucoma

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First Author: G.Samir EGYPT

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Abstract Details

Purpose:

Evaluate the benefit from measuring the biomechanical properties of the cornea in diagnosis of different types of glaucoma including angle closure glaucoma (ACG), and open angle glaucoma (OAG). Ocular response analyzer (ORA) makes dynamic measurement which includes two applanation events resulting into two different applanation values enabling measurement of viscoelastic dampening of the cornea (corneal hysteresis CH) which is the difference between these two values, while the average of these values provides highly accurate Goldman correlated intraocular pressure (IOPg), ORA also provides measurement of corneal compensated IOP (IOPcc), and corneal resistance factor (CRF).

Setting:

Ophthalmic examination including, Slit lamb examination of anterior segment , IOP measurement using Goldmann applanation tonometry (GAT), evaluation of the angle using three mirror Goldmann contact lens, measurement of CCT using Occulus pentacam, assessment of visual field using Humphery perimetry and measurement of CH, CRF, IOPcc and IOPg using ORA.

Methods:

The study includes 250 eyes, divided in to 5 groups: Group (1) composed of 50 eyes of (ACG) has undergone SST, Group (2) composed of 50 eyes of (OAG) have received medical treatment, Group (3) is composed of 50 glaucoma suspect eyes, Group (4) composed of 50 eyes having ocular hypertension, Group (5); composed of 50 normal eyes as a control group. All patients are followed up for 12 months and end points are measured one week, one month, three months and one year following surgery for the first group, and every three months, for the other four groups

Results:

CH values in groups (1,2) are significantly lower than values obtained in all other groups, while CRF values in groups (1,2) are significantly higher than values obtained in all other groups , negative correlation between CH values and all IOP values (GAT, IOPg, IOPcc), positive correlation between CRF values and all IOP values. Visual field progress has correlation with CH and CRF values only in group (2), In group (3) CRF is the only factor significantly increased during follow up. In group (4) no decrease in CH values despite increase in IOP values.

Conclusions:

Corneal biomechanics measured by corneal hysteresis (CH) values and corneal resistance factor (CRF) values using ocular response analyzer (ORA), have a strong relationship with presence of glaucoma and the risk of its progression

Financial Disclosure:

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