The most<unk> ommon<unk> l disorders are the following: *<unk> l abrasion - a medical<unk> ondition involving the loss of the surface epithelial layer of the eye's<unk>  as a result of trauma to the surface of the eye. *<unk> l dystrophy - a<unk> ondition in which one or more parts of the<unk>  lose their normal<unk> larity due to a buildup of<unk> loudy material. *<unk> l ulcer - an inflammatory or infective<unk> ondition of the<unk>  involving disruption of its epithelial layer with involvement of the<unk> l stroma. *<unk> l neovascularization - excessive ingrowth of blood vessels from the limbal vascular plexus into the<unk> ,<unk> aused by deprivation of oxygen from the air. * Fuchs' dystrophy -<unk> loudy morning vision. * Keratitis - inflammation of the<unk> . * Keratoconus - a degenerative disease, the<unk>  thins and<unk> hanges shape to be more like a<unk> one. *<unk> l Foreign body- one of the most<unk> ommon preventable occupational hazards. Management Slit lamp image of the<unk> , iris and lens (showing mild<unk> ataract) Surgical procedures Various refractive eye surgery techniques<unk> hange the shape of the<unk>  in order to reduce the need for<unk> orrective lenses or otherwise improve the refractive state of the eye. In many of the techniques used today, reshaping of the<unk>  is performed by photoablation using the excimer laser. There are also synthetic<unk> s (keratoprostheses) in development. Most are merely plastic inserts, but there are also those<unk> omposed of biocompatible synthetic materials that encourage tissue ingrowth into the synthetic<unk> , thereby promoting biointegration. Other methods, such as magnetic deformable membranes and optically<unk> oherent transcranial magnetic stimulation of the human retina are still in very early stages of research. Other procedures Orthokeratology is a method using specialized hard or rigid gas-permeable<unk> ontact lenses to transiently reshape the<unk>  in order to improve the refractive state of the eye or reduce the need for eyeglasses and<unk> ontact lenses. In 2009, researchers at the University of Pittsburgh Medical<unk> enter demonstrated that stem<unk> ell<unk> ollected from human<unk> s<unk> an restore transparency without provoking a rejection response in mice with<unk> l damage. For<unk> l epithelial diseases such as Stevens Johnson Syndrome, persistent<unk> l ulcer etc., the autologous<unk> ontralateral (normal) suprabasal limbus derived in vitro expanded<unk> l limbal stem<unk> ells are found to be effective as amniotic membrane based expansion is<unk> ontroversial. For endothelial diseases, such as bullous keratopathy,<unk> adaver<unk> l endothelial precursor<unk> ells have been proven to be efficient. Recently emerging tissue engineering technologies are expected to be<unk> apable of making one<unk> adaver-donor's<unk> l<unk> ells be expanded and be usable in more than one patient's eye.<unk> l retention and permeability in topical drug delivery to the eye The majority of ocular therapeutic agents are administered to the eye via the topical route.<unk>  is one of the main barriers for drug diffusion because of its highly impermeable nature. Its<unk> ontinuous irrigation with a tear fluid also results in poor retention of the therapeutic agents on the ocular surface. Poor permeability of the<unk>  and quick wash out of therapeutic agents from ocular surface result in very low bioavailability of the drugs administered via topical route (typically less than 5%). Poor retention of formulations on ocular surfaces<unk> ould potentially be improved with the use of mucoadhesive polymers. Drug permeability through the<unk> <unk> ould be facilitated with addition of penetration enhancers into topical formulations. Transplantation If the<unk> l stroma develops visually significant opacity, irregularity, or edema, a<unk>  of a deceased donor<unk> an be transplanted. Because there are no blood vessels in the<unk> , there are also few problems with rejection of the new<unk> . When a<unk>  is needed for transplant, as from an eye bank, the best procedure is to remove the<unk>  from the eyeball, preventing the<unk>  from absorbing the aqueous humor. There is a global shortage of<unk> l donations, severely limiting the availability of<unk> l transplants across most of the world. A 2016 study found that 12.7 million visually impaired people were in need of a<unk> l transplant, with only 1<unk>  available for every 70 needed. Many<unk> ountries have years-long waitlists for<unk> l transplant surgery due to the shortage of donated<unk> s. Only a handful of<unk> ountries<unk> onsistently have a large enough supply of donated<unk> s to meet local demand without a waitlist, including the United States, Italy, and Sri Lanka.
Cornea
Apnea
Hyperpnea
Bronchospasm
Orthopnea
Tachypnea
Hypopnea
Cyclospasm