Comparing SD-tVEP and PERG Tests Between Patients With Glaucoma, Patients With High Eye Pressure and "Normal" Patients
Condition: Glaucoma
MeSH terms: Glaucoma
Study type: Observational

Summary: 
      Wills Eye Hospital Glaucoma Research Center will conduct a 1-year prospective study to assess
      the ability of a Short Duration Transient Visual Evoked Potential (SD- tVEP) and a
      Steady-State Pattern electro-retinogram (PERG) vision testing system to detect visual
      dysfunction in patients with ocular hypertension. The study aims to assess the reversibility
      of retinal ganglion cell (RGC) dysfunction after administering intraocular pressure (IOP)
      lowering treatment. The investigators hypothesize that SD-tVEP and PERG testing will help
      develop better treatment for glaucoma patients by increasing understanding of the
      physiological relationship of IOP and RGC in glaucomatous injury.
    

Detailed description: 
      Glaucoma is the most common cause of irreversible blindness worldwide. It is characterized by
      the progressive loss of retinal ganglion cells (RGCs) and a corresponding loss of vision.
      Elevated intraocular pressure (IOP) is an important risk factor for glaucoma, but its role in
      the diagnosis of glaucoma is unclear. Although IOP-lowering therapy delays the onset of
      glaucoma in some patients with ocular hypertension, even without therapy, 90% of patients
      will not develop glaucoma over a 5-year period.

      Visual evoked potentials (VEPs) are able to detect the disruption of electrical signals at
      any point along the visual pathway, from the RGCs to the primary visual cortex. As an
      objective measure of visual function, the VEP may have an advantage over traditional visual
      field tests, by reducing confounded factors such as age, fatigue, and mental status.

      There is a growing body of evidence that SD-tVEP can objectively identify early visual
      dysfunction due to glaucoma.

      Aim 1: Compare the results of the baseline SD-tVEP and PERG vision testing in patients with
      ocular hypertension to a cohort of 30 healthy subjects and a cohort of 30 patients with
      glaucoma (of varying severity) to determine its ability to detect visual dysfunction in
      ocular hypertensive subjects.

      Aim 2: Conduct SD-tVEP and PERG testing system in 30 patients with ocular hypertension before
      and after IOP reduction with topical medication and compare the results of the SD-tVEP and
      PERG before and after treatment in each patient, to determine its ability to detect
      reversible RGC dysfunction.
    

Intervention name(s): Short Duration Transient Visual Evoked Potential (SDtVEP); Pattern electroretinogram (PERG)
Intervention type(s): Diagnostic Test; Diagnostic Test
Intervention description(s): Short duration transient visual evoked potentials (VEPs) detect disruption of electrical signals at any point along the visual pathway, from the retinal ganglion cells (RGCs) to the primary visual cortex. As an objective measure of visual function, VEP may have advantage over traditional visual field tests, by reducing confounded factors such as age, fatigue, and mental status.; Pattern electroretinogram (PERG), an objective test, is used for evaluating early damage to retinal ganglion cells (RGC). In PERG, retinal response is recorded while patterns are viewed in the visual field on a computer monitor.
Other intervention name(s): SDtVEP; PERG
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Ocular hypertension, glaucoma patients and healthy controls with no eye diseases.
      
Keywords: glaucoma; VEP; PERG; SD-tVEP; ss-PERG