Floaters or eye floaters are sometimes visible deposits within the eye's vitreous humour, which is normally transparent, or between the vitreous and retina. They can become particularly noticeable when looking at a blank surface or an open monochromatic space, such as blue sky. Each floater can be measured by its size, shape, consistency, refractive index, and motility. They are also called muscae volitantes, or mouches volantes. The vitreous usually starts out transparent, but imperfections may gradually develop as one ages. The common type of floater, present in most people's eyes, is due to these degenerative changes of the vitreous. The perception of floaters, which may be annoying or problematic to some people, is known as myodesopsia, or, less commonly, as myodaeopsia, myiodeopsia, or myiodesopsia. It is not often treated, except in severe cases, where vitrectomy (surgery), laser vitreolysis, and medication may be effective.
The vitreous body is the clear gel that fills the space between the lens and the retina of the eyeball in humans and other vertebrates. It is often referred to as the vitreous humor, from Latin meaning liquid, or simply "the vitreous". Vitreous fluid or "liquid vitreous" is the liquid component of the vitreous gel, found after a vitreous detachment. It is not to be confused with the aqueous humor, the other fluid in the eye that is found between the cornea and lens.
This is a partial list of human eye diseases and disorders.
Uveitis is inflammation of the uvea, the pigmented layer of the eye between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and includes the iris, ciliary body, and choroid. Uveitis is described anatomically, by the part of the eye affected, as anterior, intermediate or posterior, or panuveitic if all parts are involved. Anterior uveitis (iridocyclitis) is the most common, with the incidence of uveitis overall affecting approximately 1:4500, most commonly those between the ages of 20–60. Symptoms include eye pain, eye redness, floaters and blurred vision, and ophthalmic examination may show dilated ciliary blood vessels and the presence of cells in the anterior chamber. Uveitis may arise spontaneously, have a genetic component, or be associated with an autoimmune disease or infection. While the eye is a relatively protected environment, its immune mechanisms may be overcome resulting in inflammation and tissue destruction associated with T-cell activation.
Cytomegalovirus retinitis, also known as CMV retinitis, is an inflammation of the retina of the eye that can lead to blindness. Caused by human cytomegalovirus, it occurs predominantly in people whose immune system has been compromised, including 15-40% of those with AIDS.
Photopsia is the presence of perceived flashes of light in the field of vision.
Neurosyphilis is the infection of the central nervous system in a patient with syphilis. In the era of modern antibiotics, the majority of neurosyphilis cases have been reported in HIV-infected patients. Meningitis is the most common neurological presentation in early syphilis. Tertiary syphilis symptoms are exclusively neurosyphilis, though neurosyphilis may occur at any stage of infection.
Eales disease is a type of obliterative vasculopathy, also known as angiopathia retinae juvenilis, periphlebitis retinae or primary perivasculitis of the retina. It was first described by the British ophthalmologist Henry Eales (1852–1913) in 1880 and is a rare ocular disease characterized by inflammation and possible blockage of retinal blood vessels, abnormal growth of new blood vessels (neovascularization), and recurrent retinal and vitreal hemorrhages.
Coats' disease is a rare congenital, nonhereditary eye disorder, causing full or partial blindness, characterized by abnormal development of blood vessels behind the retina. Coats' disease can also fall under glaucoma.
Intraocular lymphoma is a rare malignant form of eye cancer. Intraocular lymphoma may affect the eye secondarily from a metastasis from a non-ocular tumor or may arise within the eye primarily. PIOL is a subset of primary central nervous system lymphoma (PCNSL). PCNSL are most commonly a diffuse large B-cell immunohistologic subtype of non-Hodgkin's lymphoma according to the World Health Organization (WHO) classification of lymphomas. The most common symptoms of PIOL include blurred or decreased vision due to tumor cells in the vitreous. Most cases of PIOL eventuate to central nervous system involvement (PCNSL) while only 20% of PCNSL lead to intraocular (PIOL) involvement. PIOL and PCNSL remain enigmas because both structures are immunologically privileged sites and so do not normally have immune cells trafficking through these structures. What is more, while the vast majority of PCNSL in patients with acquired immune deficiency syndrome (AIDS) is related to the Epstein-Barr virus (EBV), the development of PCNSL and PIOL in immunocompetent patients is unknown and shows no general relation to infectious DNAs.
Intermediate uveitis is a form of uveitis localized to the vitreous and peripheral retina. Primary sites of inflammation include the vitreous of which other such entities as pars planitis, posterior cyclitis, and hyalitis are encompassed. Intermediate uveitis may either be an isolated eye disease or associated with the development of a systemic disease such as multiple sclerosis or sarcoidosis. As such, intermediate uveitis may be the first expression of a systemic condition. Infectious causes of intermediate uveitis include Epstein–Barr virus infection, Lyme disease, HTLV-1 virus infection, cat scratch disease, and hepatitis C.
Epiretinal membrane or macular pucker is a disease of the eye in response to changes in the vitreous humor or more rarely, diabetes. Sometimes, as a result of immune system response to protect the retina, cells converge in the macular area as the vitreous ages and pulls away in posterior vitreous detachment (PVD).
Acute retinal necrosis (ARN) is a medical inflammatory condition of the eye. The condition presents itself as a necrotizing retinitis. The inflammation onset is due to certain herpes viruses, varicella zoster virus (VZV), herpes simplex virus (HSV-1 and HSV-2) and Epstein–Barr virus (EBV).
Intraocular hemorrhage is bleeding inside the eye. Bleeding can occur from any structure of the eye where there is vasculature or blood flow, including the anterior chamber, vitreous cavity, retina, choroid, suprachoroidal space, or optic disc.
Retinal vasculitis is inflammation of the vascular branches of the retinal artery, caused either by primary ocular disease processes, or as a specific presentation of any systemic form of vasculitis such as Behçet's disease, sarcoidosis, multiple sclerosis, or any form of systemic necrotizing vasculitis such as temporal arteritis, polyarteritis nodosa, and granulomatosis with polyangiitis, or due to lupus erythematosus, or rheumatoid arthritis. Eales disease, pars planitis, birdshot retinochoroidopathy, and Fuchs heterochromic iridocyclitis (FHI) can also cause retinal vasculitis. Infectious pathogens such as Mycobacterium tuberculosis, visceral larva migrans can also cause retinal vasculitis. Drug-induced vasculitis may involve retina as well, as seen in methamphetamine induced vasculitis.
Serpiginous choroiditis, also known as geographic helicoid peripapillary choroidopathy (GHPC), is a rare, chronic, progressive, and recurrent bilateral inflammatory disease involving the retinal pigment epithelium (RPE), the choriocapillaries, and the choroid. It affects adult men and women equally in the second to seventh decades of life.
Vogt–Koyanagi–Harada disease (VKH) is a multisystem disease of presumed autoimmune cause that affects melanin-pigmented tissues. The most significant manifestation is bilateral, diffuse uveitis, which affects the eyes. VKH may variably also involve the inner ear, with effects on hearing, the skin, and the meninges of the central nervous system.
Intravitreal injection is the method of administration of drugs into the eye by injection with a fine needle. The medication will be directly applied into the vitreous humor. It is used to treat various eye diseases, such as age-related macular degeneration (AMD), diabetic retinopathy, and infections inside the eye such as endophthalmitis. As compared to topical administration, this method is beneficial for a more localized delivery of medications to the targeted site, as the needle can directly pass through the anatomical eye barrier and dynamic barrier. It could also minimize adverse drug effects on other body tissues via the systemic circulation, which could be a possible risk for intravenous injection of medications. Although there are risks of infections or other complications, with suitable precautions throughout the injection process, chances for these complications could be lowered.
Sickle cell retinopathy can be defined as retinal changes due to blood vessel damage in the eye of a person with a background of sickle cell disease. It can likely progress to loss of vision in late stages due to vitreous hemorrhage or retinal detachment. Sickle cell disease is a structural red blood cell disorder leading to consequences in multiple systems. It is characterized by chronic red blood cell destruction, vascular injury, and tissue ischemia causing damage to the brain, eyes, heart, lungs, kidneys, spleen, and musculoskeletal system.
Secondary glaucoma is a collection of progressive optic nerve disorders associated with a rise in intraocular pressure (IOP) which results in the loss of vision. In clinical settings, it is defined as the occurrence of IOP above 21 mmHg requiring the prescription of IOP-managing drugs. It can be broadly divided into two subtypes: secondary open-angle glaucoma and secondary angle-closure glaucoma, depending on the closure of the angle between the cornea and the iris. Principal causes of secondary glaucoma include optic nerve trauma or damage, eye disease, surgery, neovascularization, tumours and use of steroid and sulfa drugs. Risk factors for secondary glaucoma include uveitis, cataract surgery and also intraocular tumours. Common treatments are designed according to the type and the underlying causative condition, in addition to the consequent rise in IOP. These include drug therapy, the use of miotics, surgery or laser therapy.
