What is actinic keratosis?
Actinic keratosis (AK), also known as solar keratosis, is a common skin condition characterized by rough, scaly patches caused by prolonged exposure to ultraviolet (UV) radiation. These lesions primarily affect sun-exposed areas such as the face,...
What is achromatopsia?
Achromatopsia is a rare inherited retinal disorder characterized by a total or partial loss of color vision. Individuals with this condition usually have difficulty distinguishing colors, poor visual acuity, and extreme sensitivity to light (photophobia). Mutations in...
Definition of Acanthamoeba Keratitis
Acanthamoeba keratitis is a rare but serious eye infection caused by a microscopic, free-living amoeba called Acanthamoeba. This organism is common in water sources such as lakes, rivers, and tap water, as well as soil and...
What is Leber's Congenital Amaurosis?
Leber Congenital Amaurosis (LCA) is a rare genetic eye disorder that causes severe vision loss from birth or within the first few months of life. This condition affects the retina, the light-sensitive tissue in the...
What is lattice dystrophy?
Lattice dystrophy is a genetic eye disorder that affects the cornea, the transparent, dome-shaped surface that covers the front of the eye. This condition is defined by the accumulation of abnormal protein fibers, known as amyloid...
What is Latent Nystagmus?
Latent nystagmus is an ocular condition defined by involuntary, rhythmic eye movements that occur only when one eye is covered. This type of nystagmus usually appears in infancy or early childhood and is frequently associated with...
What is lagophthalmos?
Lagophthalmos is an ocular condition that causes the eyelids to remain partially closed. This incomplete closure can expose the cornea and conjunctiva, causing dryness, irritation, and potentially damaging the eye. Lagophthalmos can result from a variety of...
What is a Lacrimal Gland Tumor?
Lacrimal gland tumors are abnormal growths that form in the lacrimal glands, which produce tears. These tumors, whether benign or malignant, can have a significant impact on eye health and vision. Symptoms typically include...
What is a Lacrimal Fistula?
Lacrimal fistulas are abnormal connections between the lacrimal sac and the skin or another epithelial surface. This condition allows tears to drain directly from the lacrimal sac to the skin, avoiding the normal nasolacrimal duct....
What is Lacrimal Gland Dislocation?
Lacrimal gland dislocation occurs when the lacrimal gland, which produces tears, moves out of its normal anatomical position. This dislocation can cause visible swelling, discomfort, and functional issues with tear production and drainage. Trauma, aging,...
What is a Lacrimal Fistula?
Lacrimal fistulas are abnormal connections between the lacrimal sac and the skin or another epithelial surface. This condition allows tears to drain directly from the lacrimal sac to the skin, avoiding the normal nasolacrimal duct....
What is Lacrimal Duct Obstruction?
Lacrimal duct obstruction, also known as nasolacrimal duct obstruction, is a condition that occurs when the tear drainage system of the eye becomes clogged. This blockage prevents tears from draining properly, resulting in watery eyes,...
What is keratoconus?
Keratoconus is a progressive eye disorder in which the cornea, or clear front surface of the eye, thins and bulges outward into a cone-like shape. This abnormal shape prevents light entering the eye from properly focusing on...
What is keratitis?
Keratitis is an inflammation of the cornea, the transparent, dome-shaped surface that covers the front of the eye. This condition can cause pain, redness, and vision problems, and if not treated, it can progress to severe complications,...
What is Juvenile X-Linked Retinoschisis?
Juvenile X-linked retinoschisis (XLRS) is a hereditary retinal disorder that predominantly affects men. The retinal layers split (schisis), resulting in impaired vision. The condition usually manifests in childhood and can cause a variety of visual...
What is Juvenile Open Angle Glaucoma?
Juvenile open-angle glaucoma (JOAG) is a rare but serious eye condition that typically affects people aged three to forty. Unlike primary open-angle glaucoma, which is more common in older adults, JOAG develops earlier and...
What is Juvenile Idiopathic Arthritis-Related Eye Disorder?
Juvenile idiopathic arthritis-related eye disease (JIA-associated uveitis) is an inflammatory condition that affects the eyes of children suffering from juvenile idiopathic arthritis. If not diagnosed and treated promptly, this ocular disease can cause...
What is ischemic optic neuropathy?
Ischemic optic neuropathy (ION) is a condition that causes sudden loss of vision due to decreased blood flow to the optic nerves. This condition can affect one or both eyes and is typically divided into...
What is iritis?
Iritis, also known as anterior uveitis, is an inflammatory condition affecting the iris, the colored part of the eye that surrounds the pupil. This condition may cause redness, pain, light sensitivity, blurred vision, and floaters in the...
What is Iris Nevus?
Iris nevus is a benign, pigmented growth on the iris, the colored part of the eye. These growths are typically flat or slightly raised and range in color from light to dark brown. While iris nevi...
What is Iris Dialysis?
Iris dialysis is an ocular condition in which the iris root separates or tears from its attachment to the ciliary body. This condition is frequently the result of eye trauma, which causes a variety of visual...
What is Irido-Corneal Endothelial Syndrome?
Irido Corneal Endothelial Syndrome (ICE Syndrome) is a rare ocular disorder that causes abnormal proliferation and migration of endothelial cells from the cornea to the iris. This syndrome causes a variety of clinical manifestations, including...
What is intraocular lymphoma?
Intraocular lymphoma is a rare and aggressive cancer that develops within the eye. This cancer primarily affects the vitreous, retina, and optic nerve and is frequently associated with central nervous system lymphoma, particularly in immunocompromised people....
What is internuclear ophthalmoplegia?
Internuclear Ophthalmoplegia (INO) is a rare ocular motility disorder defined by an inability to coordinate horizontal eye movements. A lesion in the medial longitudinal fasciculus (MLF), a critical brainstem pathway that connects the nuclei of cranial...
What is intermediate uveitis?
Intermediate uveitis is a type of uveitis that causes inflammation primarily in the vitreous humor and peripheral retina, both of which are located in the eye's middle layer. Unlike anterior uveitis, which affects the front of...
What is infectious uveitis?
Infectious uveitis is a serious infection-related inflammation of the uveal tract, the eye's middle layer. The uveal tract consists of the iris, ciliary body, and choroid, all of which are necessary for blood supply to the...
What is Infectious Endophthalmitis?
Infectious endophthalmitis is a severe, vision-threatening inflammation of the inside of the eye that is usually caused by infection. This condition can develop after eye surgery, penetrating ocular trauma, or systemic infections that spread to the...
What is idiopathic intracranial hypertension?
Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is a condition in which there is an increase in pressure around the brain with no obvious cause. This elevated intracranial pressure can mimic the symptoms...
What is hypotropia?
Hypotropia is a type of strabismus in which one eye deviates downward relative to the other, resulting in misalignment. This ocular condition can impair binocular vision and depth perception, resulting in symptoms like double vision, eye strain,...
What is hypophoria?
Hypophoria is a type of vertical heterophoria in which one eye drifts downward relative to the other when not actively focused on an object. It is a latent misalignment that is typically managed by the brain's fusion...
