since glaucoma is considered an optic neuropathy, new treatments for glaucoma are being continuously investigated, including neuroprotection.

Previous studies implied that phenytoin, a potent anti-convulsive drug, has a neuroprotective role, and Na+ channels blockage was suggested as a possible mechanism.

This study predicts that glaucoma patients taking Phenytoin will have a less advanced glaucoma as compared to patients not taking the drug. Glaucoma severity will be determined by visual acuity, visual fields, optic disc cupping and nerve fiber layer thickness

The study will examine adult patients who suffer from glaucoma and epileptic disorders on the same time. the study group will include glaucoma patients, being treated with oral Phenytoin for their epileptic disorder. The study group will be compared to 2 control groups:

• Glaucoma patients with epileptic disorder,receiving different medication than Phenytoin

• Glaucoma patients with no epileptic disorder.

  4 parameters will be evaluated for all groups:

  1. Best corrected visual acuity
  2. Optic disc cupping
  3. visual fields and general perimetric indices
  4. peripapillary retinal nerve fiber layer.

Every participant in the study,after giving his informed consent, will be evaluated by a senior ophthalmologist in a single office appointment. The appointment will include a visual acuity, complete ophthalmic examination,Humphrey perimetric visual field testing and peripapillary RNFL thickness measurement by OCT.

no drug or other treatment will be given to the participants

after data collection, average +/-Standard deviation for the 4 parameters will be compared between the 3 groups. Student T-test and one- way ANOVA will be used for statistical analysis.

Inclusion Criteria:

• Clinical diagnosis of glaucoma
• chronic treatment with phenytoin for any indication

Exclusion Criteria:

• pregnancy
• visual acuity less then 6/60

patients of a tertiary hospital's specialized epilepsy clinic