Clinical trial NCT00739154: Protective Effect of Phenytoin on Glaucoma
Official title: Clinical Cohort Study of Association Between Steady State Phenytoin Treatment and Better Clinical Parameters of Glaucoma
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Primary Open Angle Glaucoma
Secondary Open Angle Glaucoma
Narrow-Angle Glaucomas
Normal Tension Glaucoma
Keywords: glaucoma
Phenytoin
retinal nerve fiber layer
corrected pattern standard deviation
visual acuity
optic disc cupping
Lead sponsor: Rabin Medical Center
Sponsor class: OTHER
First posted: 2008-08-21
Enrollment: 200
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: CROSS_SECTIONAL
Sampling method: NON_PROBABILITY_SAMPLE
Study population: patients of a tertiary hospital's specialized epilepsy clinic

Brief summary: 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

Detailed description: 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.

Eligibility criteria: Inclusion Criteria:

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

Exclusion Criteria:

* pregnancy
* visual acuity less then 6/60

Primary outcomes:
measure: peripapillary RNFL thickness
timeFrame: immediate
Secondary outcomes:
measure: corrected pattern standard deviation in perimetric visual field
timeFrame: immediate
Other outcomes:
Locations:
city: Petah-Tikva
country: Israel
facility: Beilinson hospital, Rabin medical center
Study officials:
affiliation: Rabin medical center, Petah Tikva, Israel
name: Omer Y Bialer, MD
role: STUDY_DIRECTOR
affiliation: Rabin medical center, Petah-Tikva, Israel
name: Dan Gaa'ton, MD
role: STUDY_DIRECTOR
References:
citation: Chidlow G, Wood JP, Casson RJ. Pharmacological neuroprotection for glaucoma. Drugs. 2007;67(5):725-59. doi: 10.2165/00003495-200767050-00006.
citation: Ben Simon GJ, Bakalash S, Aloni E, Rosner M. A rat model for acute rise in intraocular pressure: immune modulation as a therapeutic strategy. Am J Ophthalmol. 2006 Jun;141(6):1105-11. doi: 10.1016/j.ajo.2006.01.073.
citation: Willmore LJ. Antiepileptic drugs and neuroprotection: current status and future roles. Epilepsy Behav. 2005 Dec;7 Suppl 3:S25-8. doi: 10.1016/j.yebeh.2005.08.006. Epub 2005 Oct 18.
citation: Huang D, Swanson EA, Lin CP, Schuman JS, Stinson WG, Chang W, Hee MR, Flotte T, Gregory K, Puliafito CA, et al. Optical coherence tomography. Science. 1991 Nov 22;254(5035):1178-81. doi: 10.1126/science.1957169.
citation: Mills RP, Budenz DL, Lee PP, Noecker RJ, Walt JG, Siegartel LR, Evans SJ, Doyle JJ. Categorizing the stage of glaucoma from pre-diagnosis to end-stage disease. Am J Ophthalmol. 2006 Jan;141(1):24-30. doi: 10.1016/j.ajo.2005.07.044.
citation: Klein BE, Klein R, Sponsel WE, Franke T, Cantor LB, Martone J, Menage MJ. Prevalence of glaucoma. The Beaver Dam Eye Study. Ophthalmology. 1992 Oct;99(10):1499-504. doi: 10.1016/s0161-6420(92)31774-9.
citation: Ates O, Cayli SR, Gurses I, Turkoz Y, Tarim O, Cakir CO, Kocak A. Comparative neuroprotective effect of sodium channel blockers after experimental spinal cord injury. J Clin Neurosci. 2007 Jul;14(7):658-65. doi: 10.1016/j.jocn.2006.03.023.
citation: Podos SM, Becker B, Beaty C, Cooper DG. Diphenylhydantoin and cortisol metabolism in glaucoma. Am J Ophthalmol. 1972 Sep;74(3):498-500. doi: 10.1016/0002-9394(72)90915-4. No abstract available.
citation: Naskar R, Quinto K, Romann I, Schuettauf F, Zurakowski D. Phenytoin blocks retinal ganglion cell death after partial optic nerve crush. Exp Eye Res. 2002 Jun;74(6):747-52. doi: 10.1006/exer.2002.1173.
citation: Lo AC, Black JA, Waxman SG. Neuroprotection of axons with phenytoin in experimental allergic encephalomyelitis. Neuroreport. 2002 Oct 28;13(15):1909-12. doi: 10.1097/00001756-200210280-00015.
citation: Hains BC, Waxman SG. Neuroprotection by sodium channel blockade with phenytoin in an experimental model of glaucoma. Invest Ophthalmol Vis Sci. 2005 Nov;46(11):4164-9. doi: 10.1167/iovs.05-0618.
citation: Savini G, Bellusci C, Carbonelli M, Zanini M, Carelli V, Sadun AA, Barboni P. Detection and quantification of retinal nerve fiber layer thickness in optic disc edema using stratus OCT. Arch Ophthalmol. 2006 Aug;124(8):1111-7. doi: 10.1001/archopht.124.8.1111.
citation: Carpineto P, Ciancaglini M, Zuppardi E, Falconio G, Doronzo E, Mastropasqua L. Reliability of nerve fiber layer thickness measurements using optical coherence tomography in normal and glaucomatous eyes. Ophthalmology. 2003 Jan;110(1):190-5. doi: 10.1016/s0161-6420(02)01296-4.
citation: Williams ZY, Schuman JS, Gamell L, Nemi A, Hertzmark E, Fujimoto JG, Mattox C, Simpson J, Wollstein G. Optical coherence tomography measurement of nerve fiber layer thickness and the likelihood of a visual field defect. Am J Ophthalmol. 2002 Oct;134(4):538-46. doi: 10.1016/s0002-9394(02)01683-5.
citation: Budenz DL, Chang RT, Huang X, Knighton RW, Tielsch JM. Reproducibility of retinal nerve fiber thickness measurements using the stratus OCT in normal and glaucomatous eyes. Invest Ophthalmol Vis Sci. 2005 Jul;46(7):2440-3. doi: 10.1167/iovs.04-1174.
citation: Leung CK, Chan WM, Chong KK, Yung WH, Tang KT, Woo J, Chan WM, Tse KK. Comparative study of retinal nerve fiber layer measurement by StratusOCT and GDx VCC, I: correlation analysis in glaucoma. Invest Ophthalmol Vis Sci. 2005 Sep;46(9):3214-20. doi: 10.1167/iovs.05-0294.