Effect of Phenytoin on the Ganglion Cell Layer in Patients With Optic Neuritis

Tehran University of Medical Sciences71 enrolled

Overview

Optic neuritis typically occurs in young (mean age, 32 years), female (77%) patients, and it presents as subacute monocular visual loss that develops over several days. As yet, treatment with intravenous corticosteroid for optic neuritis had no long-term beneficial effect on vision. There are a number of factors that contribute to nerve fibre damage including increased level of sodium, so blocking sodium entry could help to protect them against damage. The main objective of the study is determine whether phenytoin (which blocks sodium entry) can protect nerve fibre and improve final visual function after optic neuritis.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

QUADRUPLE

Enrollment

Conditions

Optic Neuritis

Interventions

Eligibility

Sex: ALLMin age: 18 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * isolated, unilateral, first acute optic neuritis (confirmed by neuroophthalmologist) * willing to receive a steroidal regimen * no pathologic finding in first oct * no pathology and history of optic neuritis in contralateral eye * \<14 days since onset visual loss Exclusion Criteria: * Contraindication or known allergy to Phenytoin * Use of a calcium channel or sodium channel blocker in the past 2 months * Corticosteroid use in the past 2 months * Pregnancy * Significant cardiac, renal or liver abnormalities * Prior clinical episode of optic neuritis in either eye * Bilateral acute optic neuritis * Known ocular or neurological conditions or abnormalities other than refractive error that impair visual function * Refractive error of greater than +5 or -5 diopters * Any condition that may interfere with performance of Optical Coherence Tomography (OCT): corneal, lens or fundoscopic abnormality, a co-morbid ocular condition not related to optic neuritis as detected on the OCT reading

Outcomes

Primary Outcomes

Retinal Ganglion Cell Inner Plexiform Layer Thickness

ganglion cell inner plexiform layer thickness measure in 8 sectors by Heidelberg spectral-domain Optical Coherence Tomography

Time frame: Measured at baseline and month 1, 6

Macular Layer Thickness

macular layer thickness measure in 8 sectors by Heidelberg spectral domain Optical Coherence Tomography

Time frame: Measured at baseline and month 1, 6

Best Corrected Visual Acuity

Best corrected visual acuity is converted to logMAR (logarithms of minimum angle of resolution) by statistical calculation.

Time frame: at baseline and month 6

Visual Field Mean Deviation in Decibel

The visual field is performed by the Swedish interactive thresholding algorithm standard 24-2 perimeter (Carl Zeiss mediated, Dublin, California).

Time frame: Measured at baseline and month 6

Secondary Outcomes

Retinal Nerve Fibre Layer Thickness in Micrometer

Retinal nerve fibre layer thickness measure in 8 sectors by Heidelberg spectral-domain Optical Coherence Tomography

Time frame: Measured at baseline and month1 ,6