Reference Literature

  • Age-Related Macular Degeneration (AMD)

    Summary of select, peer reviewed published research on age related macular degeneration: Age-related macular degeneration (AMD) is a common eye disease that is the leading cause of vision loss for people over 50 years of age. There are two versions of AMD, dry and wet.

  • Dark-adapted Red Flash Electroretinography (ERG)

    The dark-adapted red flash is an extension of the standard full-field ERG. It incorporates a dim red flash of light which elicits an x-wave that illuminates further detail of the rod pathway physiology.  This protocol can be used in the diagnosis of achromatopsia (rod monochromacy), cone dystrophy, and other cone system dysfunctions. They are apparent…

  • Diabetic Retinopathy

    Summary of select, peer reviewed published research on diabetic retinopathy: Within the first two decades following the diagnosis of diabetes, nearly all patients with type 1 diabetes and 60% of patients with type 2 diabetes will develop diabetic retinopathy (DR). Despite better diabetes management and glycemic control, DR remains a major health concern due to…

  • Electrodes for Clinical Practice

    Key Topics Active electrodes record the signal from the stimulated region, reference electrodes record ambient noise, and the ground electrode serves as the zero reference for the positive or negative polarity of the signal. Comparison of commonly used ERG active electrodes for signal amplitude (specifically signal to noise ratio) and patient comfort. Limited options for…

  • Electrooculogram (EOG)

    An electrooculogram (EOG) measures the resting potential of the retinal pigmented epithelium (RPE) in response to dark and light conditions. A foundational principle of this test is the potential difference between the front and the back of the eye. The retina lining the back of the eye is more negative due to the neurons and…

  • Glaucoma

    Summary of select, peer reviewed published research on glaucoma: Glaucoma is a group of conditions characterized by cupping of the optic disc with corresponding visual field defects due to retinal ganglion cell (RGC) loss. In some cases, the condition can progress to the point of causing optic neuropathy. It is the most common cause of…

  • Inherited Retinal Diseases (IRD)

    Selected peer reviewed published research on Inherited Retinal Diseases: Inherited Retinal Diseases (IRDs) are caused by different gene mutations that can cause vision loss due to dysfunction primarily of the photoreceptors. Electrophysiology (ffERG, mfERG, PERG, PhNR, EOG, EER) responses are objective measures of retinal function and assist in accurately differentiating between IRDs as well as…

  • ISCEV Guide

    Diagnosys equipment is capable of performing the following protocols: Full field ERG (ffERG), Multifocal ERG (mfERG), Pattern ERG (PERG), Photopic Negative Response (PhNR), Pattern VEP, Flash VEP, Stepwise Sweep VEP, Electro-oculogram (EOG), and Electrically Evoked Response (EER) tests. The resulting size, shape, and delay of various components of the response waveforms are indicators evaluated by…

  • Multifocal Electroretinography (mfERG)

    The Multifocal ERG (mfERG) test shows visual function across the macula. This test divides the macula into multiple hexagonal regions. The stimulus is a pseudo-random sequence of black and white hexagons that alternate many times per second. A standard ERG electrode setup is used to record the signal, and mathematical extraction is used to create…

  • Neurological Conditions

    Selected peer reviewed published research on Neurological Conditions: There are several neurological conditions that may affect the visual pathway from the optic nerve head to the visual cortex resulting in vision loss or even blindness. Electroretinograms (ERGs) and visual evoked potentials (VEP) are useful in clinical diagnosis as well as evaluating the severity of optic…

  • On-Off Electroretinography (on-off ERG)

    The On-Off ERG is a separate protocol used to investigate post-phototransduction or post-receptor dysfunction. This protocol elicits a response from the bipolar and inter-retinal cells. ISCEV indicates that his protocol may further reveal details about: CSNB, melanoma-associated retinopathy, and some forms of autoimmune retinopathy. This protocol may also be useful in X-linked retinoschisis, Batten disease,…

  • Pattern Electroretinography (pERG)

    The Pattern ERG (pERG) produces a macular retinal ganglion cell response. When done as a follow-up to an abnormal pattern VEP, the pERG can elucidate whether the abnormality is caused by retinal or optic nerve dysfunction. This test may also assist in diagnosing glaucoma, optic neuropathies, and primary ganglion cell diseases.  A pERG can be…

  • Pediatric Conditions

    Selected peer reviewed published research on Pediatric Conditions: There are several pediatric disorders that may cause vision loss or blindness in children due to retinal, visual pathway, or cortical pathology. The objective data obtained by electroretinograms, electrooculargrams, and visual evoked potentials are an integral part to the diagnosis and monitoring of infants and children either…

  • Photopic Negative Response (PhNR)

    A Photopic Negative Response (PhNR) is a test of generalized retinal ganglion cell health and function. Reduced PhNR amplitudes might be indicators for: glaucoma, optic atrophy, central retinal artery occlusion, ischemic optic neuropathy, diabetic retinopathy, or idiopathic intracranial hypertension.  This protocol uses a low intensity red flash on a rod-saturating blue background. It can be…

  • Retinal Toxicity

    Summary of select, peer reviewed published research on retinal toxicity: Hydroxychloroquine (HCQ) and its predecessor, chloroquine (CQ) are antimalarial drugs with well-established benefits for treating rheumatoid arthritis, lupus and other connective tissue and skin disorders. Extensive research has shown long-term usage of either drug to be associated with retinal toxicity. Early detection of HCQ/CQ retinopathy…

  • S-Cone Electroretinography (ERG)

    The short-wavelength cone (S-Cone) ERG protocol tests the blue-light receptor retinal pathway. This test can be useful for diagnosing inherited retinal disorders and distinguishing between rod monochromacy and S-cone monochromacy.  The S-Cone protocol can be run on a ColorDome stimulator that delivers flashes of blue light on an amber-colored background. The background light serves to…

  • Stepwise Sweep Visually Evoked Potentials (ssVEP)

    Sweep VEP is an objective method to estimate a person’s visual acuity. This test is useful for patients with unexplained vision loss or any adult / child who is unwilling or unable to perform a subjective acuity test.     How it works Similar to a 3-channel VEP, Sweep VEP utilizes three active scalp electrodes: one…

  • The Full-field Sensitivity Threshold (FST) for Ophthalmic Diagnosis

    What is the FST? The FST is a psychophysical test with distinct advantages over other tests for quantifying vision in individuals with advanced retinal degeneration. At its core, the FST assesses visual field sensitivity by determining the lowest luminance flash which elicits a visual sensation perceived by the patient. The test may be done in…

  • Visually Evoked Potentials (VEP)

    Visually Evoked Potentials (VEPs) are used to investigate conduction along the visual pathway. They may be used to quantify and follow progression of nerve pathology, localize lesions and measure slow –downs for multiple reasons such as: compression, inflammation, demyelination, or trauma.  A VEP is recorded using a scalp electrode(s) placed over the occipital lobe of…