What is Lacrimal Gland Dislocation?
Lacrimal gland dislocation is a condition in which the lacrimal gland, which produces tears, moves out of its normal anatomical position. This gland, located in the upper outer quadrant of the orbit, just above the...
What is a Lacrimal Fistula?
A lacrimal fistula is an abnormal connection or passageway formed between the lacrimal sac (a component of the tear drainage system) and the skin or other anatomical structures. This condition can cause chronic tearing (epiphora),...
What is Lacrimal Duct Obstruction?
Lacrimal duct obstruction, also known as nasolacrimal duct obstruction (NLDO), is a condition that occurs when the tear ducts become clogged, preventing tears from draining properly from the eye into the nasal cavity. This causes...
What is keratoconus?
Keratoconus is a progressive eye condition in which the normally round, dome-shaped cornea thins and bulges into a cone-like shape. This abnormal shape deflects light as it enters the eye, resulting in distorted vision. The exact cause...
What is keratitis?
Keratitis is an inflammation of the cornea, which is the clear front part of the eye that protects the iris, pupil, and anterior chamber. Infections (bacterial, viral, fungal, or parasitic), physical or chemical injury, and underlying systemic...
What is Juvenile Open Angle Glaucoma?
Juvenile open-angle glaucoma (JOAG) is a rare but serious form of glaucoma that affects children, adolescents, and young adults aged 10 to 35. It is distinguished by an increase in intraocular pressure (IOP) as...
What is ischemic optic neuropathy?
Ischemic optic neuropathy (ION) is a condition that causes sudden loss of vision due to insufficient blood flow to the optic nerve. The optic nerve is responsible for transmitting visual information from the retina to...
What is iritis?
Iritis, also known as anterior uveitis, is an inflammation of the iris, the colored area of the eye that surrounds the pupil. It is a subset of uveitis, which is defined as inflammation of the uvea, the...
What is Iris Nevus?
An iris nevus is a harmless pigmented lesion on the iris, the colored portion of the eye. These lesions are usually flat, but they may occasionally be slightly elevated. Melanocytes, the cells responsible for pigment production,...
What is Iris Dialysis?
Iris dialysis is a condition in which the iris detaches or separates from its ciliary attachments. This ocular condition is frequently the result of eye trauma, such as blunt force injuries, surgical complications, or penetrating injuries....
What is intraocular lymphoma?
Intraocular lymphoma is a rare and aggressive type of cancer that affects the eye. It is a subtype of primary central nervous system lymphoma (PCNSL), a type of non-Hodgkin lymphoma. Intraocular lymphoma primarily affects the retina,...
What is internuclear ophthalmoplegia?
Internuclear ophthalmoplegia (INO) is a neurological condition characterized by decreased horizontal eye movement. A lesion in the medial longitudinal fasciculus (MLF), a bundle of nerve fibers that connects the cranial nerve nuclei involved in horizontal gaze,...
What is intermediate uveitis?
Intermediate uveitis is a type of uveitis, which is an inflammatory condition affecting the uvea, the eye's middle layer. Intermediate uveitis primarily affects the vitreous and peripheral retina. The condition can cause significant visual disturbances and,...
What is infectious uveitis?
Infectious uveitis is a type of uveitis, which is an inflammatory condition affecting the uvea, the middle layer of the eye that contains the iris, ciliary body, and choroid. Infectious agents such as bacteria, viruses, fungi,...
What is Infectious Endophthalmitis?
Infectious endophthalmitis is a severe and potentially blinding inflammation of the eye's interior that is typically caused by a bacterial or fungal infection. This condition usually affects the vitreous and aqueous humors and can result in...
What is hypotropia?
Hypotropia is a type of strabismus in which one eye deviates downward relative to the other, causing misalignment. This condition can be congenital or acquired, and it may be associated with other ocular or systemic issues. Hypotropia...
What is hypophoria?
Hypophoria is an ocular condition defined by a latent tendency for one eye to drift downward when the eyes are not actively focusing on a single target. Unlike manifest strabismus, which is always visible, hypophoria is latent...
What is hyphema?
Hyphema is an ocular condition characterized by the presence of blood in the anterior chamber of the eye, which is located between the cornea and the iris. This condition is typically caused by eye trauma, such as...
What is hypertropia?
Hypertropia is an ocular condition characterized by eye misalignment, with one eye higher than the other. This vertical deviation disrupts normal binocular vision and can cause a variety of visual issues, including double vision (diplopia), eyestrain, and...
What is hypertensive retinopathy?
Hypertensive retinopathy is an ocular condition caused by chronically high blood pressure, which can damage the retina, the light-sensitive tissue at the back of the eye. The retina plays an important role in vision by converting...
What is hyperphoria?
Hyperphoria is a type of latent strabismus in which one eye deviates upward relative to the other. This misalignment occurs only when the binocular vision system is disrupted, for example, when one eye is covered or stressed....
What is hyperopia?
Hyperopia, also known as farsightedness, is a common refractive error in which distant objects appear more clearly than near ones. This condition develops when the eyeball is too short or the cornea has insufficient curvature, causing light...
What is Hordeolum?
Hordeolum, also known as a stye, is an acute, localized infection or inflammation of the eyelid margin that usually affects the hair follicles of the eyelashes or the meibomian gland. It appears as a painful, red, and...
What is Homonymous Hemianopia?
Homonymous hemianopia is a visual field defect caused by damage to the brain's visual pathways, which is usually caused by a stroke, traumatic brain injury, tumors, or another neurological condition. This condition causes both eyes to...
What is herpes zoster ophthalmicus?
Herpes zoster ophthalmicus (HZO) occurs when the varicella-zoster virus (VZV), which causes chickenpox, reactivates within the ophthalmic branch of the trigeminal nerve. This reactivation results in a painful and potentially serious infection of the eye...
What is herpes simplex keratitis?
Herpes simplex keratitis (HSK) is a condition of the eyes caused by the herpes simplex virus (HSV), primarily HSV-1, which also causes cold sores. It affects the cornea, the transparent front part of the eye,...
What is hereditary retinal dystrophy?
Hereditary retinal dystrophies (HRDs) are a diverse group of genetic disorders that cause progressive retinal degeneration, resulting in vision impairment and, in severe cases, blindness. The retina, a thin layer of tissue at the back...
What is hereditary optic neuropathy?
Hereditary optic neuropathies are a collection of genetic disorders that cause progressive damage to the optic nerve, resulting in vision loss. The most common types of these conditions are Leber's Hereditary Optic Neuropathy (LHON) and...
What is gonococcal conjunctivitis?
The bacterium Neisseria gonorrhoeae, which is also responsible for the sexually transmitted infection gonorrhea, causes gonococcal conjunctivitis, a severe and potentially blinding eye infection. This condition can affect people of all ages, but it is especially...
What is Globe Rupture?
Globe rupture is a severe and often vision-threatening ocular condition that occurs when trauma compromises the integrity of the eye's outer membrane. This condition is typically caused by blunt or penetrating trauma to the eye, resulting...
