• Binocular vision – when both eyes work together, looking in the same direction, usually creating a sense of depth perception
  • Blocked tear duct – AKA: Nasolacrimal duct obstruction – see Common Vision Problems
  • Brown’s Syndrome – a lack of elevation of one eye when it’s looking toward the nose. The eye can also shoot downward.


  • Cataracts – a clouding of the focusing lens inside the eye that may lead to decreased vision – see Common Vision Problems
  • Chalazion – a chronic lump in an eyelid caused by a plugged gland
  • Color-blindness – decreased perception of color, see common conditions – see Common Vision Problems
  • Convergence insufficiency – a decrease in the ability of the eyes to move together as they are looking at objects moving closer
  • Conjunctivitis – inflammation of the layer of tissue that covers the sclera, the white of the eye. Conjunctivitis can be caused by viruses, bacteria, allergies or any substance that irritates an eye. The type of conjunctivitis determines the type of treatment.
  • Cranial nerve palsies – a paralysis of one or more nerves that pass from the brain to parts of the face and neck. This can cause strabismus and ptosis, among other things. – see Common Vision Problems
  • Cross-eyed – see esotropia


  • Dacryocystoplasty – a procedure sometimes used to correct nasolacrimal duct obstruction where a probe with a balloon on it is passed from the corner of the eye, down the nasolacrimal duct and into the nose. The balloon is inflated to stretch open the duct, thus improving tear flow.
  • Depth perception – a sense of the three dimensions when the eyes work together
  • Diplopia – AKA: Double vision, when two things are seen and only one is present or one objet may appear on top of the other.
  • Double vision – see diplopia


  • Ectropion – Outward turning of one or both of the eyelids so that the lid margin does not rest against the eyeball, but falls or is pulled away. This can create corneal exposure with excessive drying, tearing, and irritation.
  • Esotropia – a turning inward of one or both eyes– see Common Vision Problems
  • External eye disease – any condition that causes irritation of the eyelids and/or surface of the eye
  • Exotropia – one eye drifts outward intermittently or all of the time – see Common Vision Problems
  • Entropion – inward turning of one or both eyelids so that the lid margin rests against and rubs the eyeball


  • Floaters – small shadow caused by bits of tissue floating in the back of the eye. They may be a sign of retinal damage
  • Farsightedness – see hyperopia and Common Vision Problems


  • Glaucoma – a build up of pressure in the eye that can eventually lead to loss of vision – see Common Vision Problems


  • Hordeolum – a lump on the eyelid caused by a plugged up gland, commonly called a stye
  • Hyphema – abnormal bleeding in the eye between the cornea and iris, usually caused by trauma
  • Hyperopia – commonly referred to as farsightedness, usually corrected with contacts, glasses or surgery, where it takes more effort to see up close – see Common Vision Problems
  • Hypertropia – one eye drifts above or below the other eye – see Common Vision Problems
  • Hypotropia – one eye drifts above or below the other eye – see Common Vision Problems


  • Infracture of the turbinates – a procedure where a small bone in the nose is purposely broken away from the bottom of the nasolacrimal duct, allowing a clear passage of tears
  • Intubation – placement of a silicone tube from the inner corner of the eye, through the nasolacrimal duct and into the nose to hold the nasolacrimal duct open


  • K-readings – corneal measurements used mainly in the fitting of contact lenses



  • Myopia – a condition that causes blurred distance vision, commonly referred to as near-sightedness. Myopia is usually corrected through contact lenses, glasses, or surgery – see Common Vision Problems


  • Nasolacrimal duct obstruction – commonly referred to as tear duct obstruction. This usually occurs in infants, resulting in tearing and discharge from one or both eyes – see Common Vision Problems
  • Nearsightedness – see myopia and Common Vision Problems
  • Nystagmus – an abnormal rapid movement of the eyes associated with decreased vision or neurological problems


  • Ophthalmologist – a licensed medical doctor who diagnoses and treats visual and medical eye problems of all varieties, including surgery
  • Optician – a person who fits and fills glasses and contact lens prescriptions
  • Optometrist – a licensed doctor of optometry who diagnoses and treats visual problems. In some states this includes certain medication prescriptions and some minor surgical procedures


  • Patching – part to full time covering of the dominant eye to force the amblyopic eye to be used and improve its vision
  • Pink eye – see conjunctivitis
  • Probe and irrigation – a procedure performed to clear obstructions for a clogged tear duct – see Common Vision Problems
  • Ptosis – a drooping of one or more eyelids


  • Retina – the thin layer in the back of the eye that senses light and transmits the information from the eye, through the optic nerve and to the brain where the information is translated into sight
  • Retinal detachment – when all or part of the retina is pulled off of the inside of the back of the eye, separating it from most of its blood supply, eventually leading to loss of vision
  • Retinal tear – a tear in the retina that can lead to a retinal detachment
  • Retinopathy of prematurity – a condition that occurs in small premature babies where the retinae and its blood supply develop abnormally. Most of the time the condition is mild and does not need treatment. More severe forms may require laser and/or retinal surgery in an attempt to prevent blindness.



  • Tear duct problem – see nasolacrimal duct obstruction
  • Thyroid eye disease (aka Graves’ Disease) – a condition that occurs in patients with excessive thyroid related problems. The condition may cause eyelid retraction, eyelid lag on downward gaze, corneal drying, eye bulging (proptosis), fibrotic extraocular muscles, and optic nerve damage and strabismus. – see Common Vision Problems
  • Trichiasis – Misdirected eyelashes that turn inward toward the eyeball and may scratch the cornea.


  • Wall-eyed – see exotropia