Measurement of wavefront aberrations using an aberrometer.
The measurement of the aberrations of the wavefront is used for diagnostic purposes to determine the causes of some visual disturbance, but are also used for programs ablation procedures guided by wavefront, both in patients undergoing eye surgery with laser for the first time, both in patients who require therapeutic retreatments.
The wavefront is done with a tool called aberrometer. There are various aberrometri available. In general, any company that produces an excimer laser has its own particular type of aberrometer.
There are three different types of aberrometrie wavefront: the principle of Hartmann-Shack, the principle of Tscherning and ray tracing.
Allergen substance usually harmless to most people, but that in certain individuals (allergic subjects) is able to produce allergic manifestations of various nature (asthma, urticaria, etc..).
Asthenopia accommodative visual fatigue due to a disturbance of accommodation.
Cataract process of progressive opacification of the lens attached to oxidation of proteins that costituiscono.Si is a typical disease of aging, but can also affect less advanced age, especially if related to secondary factors (diabetes, congenital and iatrogenic causes).
Conjunctiva, the mucous membrane that covers the eyeball and the inside of the eyelids; has the function of protecting the eyeball, especially the cornea, as well as to facilitate its sliding and of that of the eyelids in the phases of winking.
Conjunctivitis is an inflammation of the conjunctiva to load.
Choroid part of the uvea together with the ciliary body and iris. It is a thin membrane of the eye, located between the sclera and the retina, provided with many blood vessels that nourish the retinal tissue.
Ciliary crown formed by a iento of corioide, it looks like a collar between the part of corioide properly so called and the iris. The corioide is the middle layer of the eye, rich in blood vessels and with a large amount of pigment. In addition to the ciliary body, the corioide also belong the sensor apparatus and the iris.
Vitreous body (also called vitreous humor) is a gelatinous mass, transparent and colorless that fills the back of the eyeball 4.5, to be precise in the vitreous cavity which is the space between the posterior surface of the lens and the retina.
Crystalline structure in the shape of a biconvex lens, perfectly transparent, situated between the iris (before) and the vitreous body (posteriorly) whose function is to focus on objects on the retina through continuous variations of its curvature.
Ectoprion rotation erso the outside of the eyelid (it "turns" the eyelid margin). It is often a complication of facial nerve paralysis. Can also occur in animals (for example in the dog).
Eyelid edema localized swelling of the eyelids due to infectious or inflammatory processes, trauma, or other disease processes.
Entropion eye disease that is the inward rotation of the eyelid margin. The disease may occur on both eyelids of a single eye, although often known only at the bottom. The eyelashes are to be found in contact with the eyeball and the scratch. The lesions of the cornea can often turn into ulcers; is what can be done, for example, if you are affected by trachoma.
Retinal pigment epithelium (RPE) complex layer of cells located between Bruch's membrane and the most peripheral of the cones and rods and that regulates the passage of substances to and from the metabolic retina.
Photophobia symptom of excessive for sensitivity to light and the aversion to sunlight or well-lit places. In medical terms it is not fear, but an experience of discomfort or pain to the eyes due to exposure to light.
Walleye very diverse group of eye diseases, linked by the presence of a chronic and progressive damage of the optic nerve, with characteristic changes in the appearance of the optic nerve head, retinal nerve fiber layer, even in the absence of other ocular diseases.
Diseases are important as they can cause injury not reversible.
Iris diaphragm muscle of the eye varies in color, shape and function of the diaphragm, pigmented, located behind the cornea and in front of the lens, perforated by the pupil.
Lipoperoxidation typical reaction of free radicals for which these molecules oxidize lipids, particularly those of the cell membranes, damaging the structure and thus the integrity of the cell.
Metabolism with chemical processes that take place in a living organism, aimed at growth, energy production, etc.. These processes can be anabolic (production of substrates) or catabolic (demolition of the substrates). The basal metabolic rate is the minimum energy needed to keep the body in life in terms of physical rest, digestive and emotional.
Floaters [Myodes from the greek 'like flies' and Opsis 'vision'] or floaters are the manifestation of moving shadows in the visual field of the eye due to an imperfect transparency of the vitreous body, which over time, is hit by a process degenerative.
Disease refers to any disease, both man, animals or plants. The disease is also the discipline of medicine that deals with the study of diseases, their pathophysiology and etiological, their classification and their epidemiology. It is specifically the development of the physiology of that, however, studies the normal functioning of the organism.
Posterior pole inside rear of the eyeball which includes the papilla (optic nerve) and the macula, which is the area that corresponds to the part of the retina between the two branches of the temporal branch central retinal artery.
Presbyopia visual defect characterized by progressive loss of sharp vision closely due to a reduction of elasticity of the crystalline lens, and then the accommodative power. This defect typically occurs after age 40, and the need to wear glasses for reading.
Punctal plugs small "caps" silicone (absorbable) or plastic material (not absorbable) used for the punctal occlusion. If an improvement is obtained of the lubrication of the ocular surface, the dots can be permanently closed by means of a small surgical intervention.
Pupil, which etymologically means doll, the hole is located at the center of the iris, of variable diameter, which allows the entry of light inside the eyeball. Its dimensions are regulated, based on the intensity ambient light, by a system of muscles that depend on the autonomic nervous system: the dilates when the muscle (mydriasis) is to receive greater amount of light, vice versa the narrows (miosis) in the presence of plenty of light (just as in a camera lens, with the aperture).
Free radical molecules produced during normal biological processes that, because of the loss of an electron, are highly reactive and unstable. The free radicals interact particularly with molecules of the cell membrane, with enzymes, fatty acids and other cell components, oxidizing and, therefore, damaging them.
Retina is the innermost membrane dell'occhio.Con its cells sensitive to light radiation (photoreceptors), it sends to the brain via the optic nerve, the information to be interpreted. Among the cells that make up the retina must be mentioned: the cones are responsible for color vision but sensitive only to light quite intense; and rods, which are particularly sensitive to low light intensities but not the colors.
Retinitis pigmentosa, also referred to by the acronym RP is a genetic disease of the eye. One of the first symptoms is to reduce the view of night to night blindness.
The RP is a type of retinal dystrophy, a group of inherited disorders in which abnormalities of the photoreceptors (rods and cones) or the retinal epithelium pigmentosum or retina itself leads to a gradual and progressive loss of vision.
Retinoblastoma is an eye condition, and represents the tumor mealigno with more widespread in children.
Anterior segment of the front of the eyeball that covers the cornea, the iris and the lens.
Scavenger English term synonymous with antioxidant. The scavenger term refers to the ability of antioxidants to supply electrons to free radicals so that they stick to the antioxidant molecule. Following this binding free radicals are subtracted to biological reactions becoming in this way harmless.
Symptom derives from the greek σύμπτωμα: 'just in case', 'circumstance'; in turn derived from συμπιπτω: 'fall in, fall together'). fact, the symptom is never a single entity phenomenal, but the final effect is not standardized, a convergence of multiple actions and reactions. Indicates an alteration in the normal sense of self and of one's body in relation to a pathological condition, reported by the patient. It differs from the sign that it is instead an objective pathological findings on physical examination recognized by the physician of the patient.
Trachoma (from the ancient greek "rough eye") is a 'bacterial infection of the conjunctiva and cornea caused by Chlamydia trachomatis, an obligate intracellular gram-negative bacterium.
Trichiasis abnormal development of the eyelashes inwards so as to potentially cause ulceration or corneal lesions. It can be observed nell'entropion.
Uvea is also called the uveal layer, uveal coating and uveal tract: it is a pigmented layer, with its characteristic dark red-purple. It can catch fire: in this case arises uveitis, which should be treated promptly by a specialist because in some cases, if left untreated, can lead to blindness.