demodex blepharitis is an eyelid inflammation associated with Demodex mites living around the eyelashes and eyelid glands. It is commonly discussed in eye clinics when people have chronic “blepharitis” symptoms that don’t fully respond to routine care. The condition often involves irritation at the lash line and debris on the lashes. It is used as a clinical diagnosis to explain symptoms, guide testing, and select appropriate management options.

rosacea blepharitis is eyelid margin inflammation associated with rosacea, a chronic inflammatory skin condition. It commonly involves irritation around the eyelashes and oil glands at the lid edge. Clinicians use the term when eyelid findings occur alongside facial flushing, redness, or rosacea history. It is discussed in eye care, dermatology, and dry eye disease evaluation.

posterior blepharitis is inflammation and dysfunction at the back edge of the eyelid margin, where the oil glands open. It is commonly linked to meibomian gland dysfunction (MGD), which affects the tear film’s oily layer. People often notice irritation, burning, fluctuating vision, or “dry eye” symptoms. The term is used in eye clinics to describe a frequent, often chronic cause of ocular surface discomfort.

anterior blepharitis is inflammation along the front edge of the eyelid where the eyelashes attach. It commonly involves flakes, debris, or irritation at the lash line. Clinicians use the term to describe a specific eyelid-margin disorder and to guide evaluation of related dry eye and surface symptoms. It is a frequent topic in eye clinics because symptoms can be chronic and recurrent.

blepharitis is inflammation of the eyelid margins, where the eyelashes and oil glands sit. It commonly causes irritation, redness, crusting, and symptoms that overlap with dry eye. Clinicians use the term in eye care to describe several related eyelid conditions with similar signs. It is discussed in both patient education and clinical training because it can be chronic and recurrent.

meibomian gland dysfunction (MGD) is a common condition in which the eyelid’s oil-producing glands do not work normally. These glands help stabilize the tear film, which keeps the eye surface comfortable and vision clear. When the oil layer is abnormal, tears may evaporate too quickly and the eye surface can become irritated. The term is commonly used in eye clinics when evaluating dry eye symptoms, eyelid health, and contact lens discomfort.

evaporative dry eye is a form of dry eye disease where tears evaporate too quickly from the eye surface. It most often relates to problems with the tear film’s oily layer and the eyelid glands that produce it. The term is commonly used in eye clinics to describe a major cause of burning, irritation, and fluctuating vision. It is also used in research and education to separate “tear evaporation” problems from “low tear production” problems.

aqueous-deficient dry eye is a form of dry eye disease where the eyes do not produce enough watery tears. It can cause burning, gritty sensation, fluctuating vision, and sensitivity to light or wind. The term is commonly used in eye clinics to describe a specific mechanism of dry eye and to guide evaluation. It is discussed in ophthalmology and optometry because it may be linked to eyelid, ocular surface, or systemic conditions.

keratoconjunctivitis sicca is the clinical term for “dry eye” that affects both the cornea and the conjunctiva. It describes an ocular surface condition where the tear film does not adequately protect and lubricate the eye. The term is commonly used in eye clinic notes, research literature, and diagnostic coding.

dry eye disease is a common condition in which the eye’s tear film does not adequately lubricate and protect the ocular surface. It can cause discomfort, visual fluctuation, and irritation that may come and go or persist over time. The term is used in eye clinics to describe a specific set of symptoms and clinical findings related to tear film dysfunction. It is discussed across ophthalmology, optometry, primary care, and vision science because it affects everyday activities like reading and screen use.

pattern standard deviation (PSD) is a number reported on many automated visual field tests. It describes how “uneven” a person’s sensitivity is across the tested field of vision. It is commonly used in glaucoma care and neuro-ophthalmology to summarize localized visual field loss. It is interpreted alongside other visual field indices and the full test printout.

mean deviation (MD) is a single number that summarizes how much a visual field test differs from expected normal vision for a person’s age. It is most commonly reported on automated perimetry tests used in glaucoma care and neuro-ophthalmology. It is expressed in decibels (dB) and typically becomes more negative as overall visual field loss increases. Clinicians use it as a “global index” to track change over time alongside other measurements.

visual field index (VFI) is a single number that summarizes how much of a person’s visual field is functioning compared with an age-adjusted “normal” reference. It is most commonly reported on automated visual field tests used in glaucoma care. Clinicians use it to describe severity and to track change over time in a way that is easy to trend. For patients, it can be a simpler snapshot than reading every point on a visual field printout.

orbital MRI is a magnetic resonance imaging scan focused on the eye sockets (orbits) and nearby structures. It creates detailed pictures of soft tissues, such as the optic nerve, eye muscles, and orbital fat. It is commonly used in ophthalmology, optometry referral pathways, neurology, and radiology. It helps clinicians evaluate eye-related symptoms when the cause may involve deeper tissues that cannot be seen on routine eye exam.

orbital CT is a computed tomography scan focused on the eye sockets (the orbits) and nearby facial structures. It uses X‑rays and computer processing to create detailed cross‑sectional images. It is commonly used in emergency care, eye clinics, and hospital radiology departments. Clinicians use it to evaluate trauma, inflammation, infection, tumors, and many orbital and sinus problems.

visual evoked potential (VEP) is a test that measures how the brain’s visual system responds to visual stimulation. It records tiny electrical signals from the back of the head (the visual cortex) after the eyes see a pattern or flash of light. Clinicians use it to evaluate how well signals travel from the eye through the optic nerve to the brain. It is commonly used in neuro-ophthalmology, optometry, and neurology when vision symptoms are difficult to explain with routine eye exams alone.

electro-oculography (EOG) is a test that records small electrical signals related to eye position and retinal health. It uses skin electrodes placed around the eyes to measure changes in electrical potential as the eyes move. In ophthalmology, it is most known for evaluating retinal pigment epithelium (RPE) function in certain retinal disorders. It is also used in some vestibular (balance) and neurology settings to track eye movements.

multifocal ERG is a retinal function test that records tiny electrical signals generated inside the eye in response to light patterns. It measures how different small areas of the central retina are working, rather than giving one overall average result. It is commonly used in ophthalmology and optometry clinics to evaluate unexplained vision symptoms and to support diagnosis or monitoring of macular and retinal conditions. It is a diagnostic test, not a treatment.

electroretinography (ERG) is a diagnostic test that measures the retina’s electrical responses to light. It helps clinicians assess how well retinal cells are functioning, even when the retina looks normal on exam. It is commonly used in ophthalmology and optometry clinics, hospital eye departments, and specialized retina practices. It can support diagnosis and monitoring of inherited, toxic, and ischemic retinal conditions.

esthesiometry is the measurement of sensation, most often the sensitivity of the cornea (the clear front window of the eye). It helps clinicians understand how well the eye can detect touch or other stimuli on the ocular surface. It is commonly used in ophthalmology and optometry to evaluate corneal nerve function. It can support the assessment of dry eye, nerve-related corneal disease, and recovery after certain eye surgeries.