Brief the hypermetropia with causes and correction, along with (the ray diagram)
pls tell its an emergency
Answers
Answer:
Hypermetropia occurs because the converging power of the eye lens is low and the images of nearby objects are formed behind the retina. As a result, the person cannot see these objects clearly. ... The following ray diagram explains the hypermetropic eye and how the defect is corrected by using convex lenses.
Explanation:
Far-sightedness, also known as hypermetropia, is a condition of the eye in which light is focused behind, instead of on, the retina. This results in close objects appearing blurry, while far objects may appear normal.As the condition worsens, objects at all distances may be blurry. Other symptoms may include headaches and eye strain. People may also experience accommodative dysfunction, binocular dysfunction, amblyopia, and strabismus.The cause is an imperfection of the eyes. Often it occurs when the eyeball is too short, or the lens or cornea is misshapen. Risk factors include a family history of the condition, diabetes, certain medications, and tumors around the eye. It is a type of refractive error. Diagnosis is based on an eye exam.Management can occur with eyeglasses, contact lenses, or surgery. Glasses are easiest while contact lenses can provide a wider field of vision. Surgery works by changing the shape of the cornea. Far-sightedness primarily affects young children, with rates of 8% at 6 years and 1% at 15 years. It then becomes more common again after the age of 40, affecting about half of people.
Signs and symptom :-
The signs and symptoms of far-sightedness are blurry vision, headaches, and eye strain. The common symptom is eye strain. Difficulty seeing with both eyes (binocular vision) may occur, as well as difficulty with depth perception.
Complications :-
Far-sightedness can have rare complications such as strabismus and amblyopia. At a young age, severe far-sightedness can cause the child to have double vision as a result of "over-focusing".
Causes :-
As hyperopia results from the visual image being focused behind the retina, it has two main causes:
! Low converging power of eye lens because of weak action of ciliary muscles
! Abnormal shape of the cornea
Far-sightedness is often present from birth, but children have a very flexible eye lens, which helps to compensate.[7] In rare instances hyperopia can be due to diabetes, and problems with the blood vessels in the retina.
Diagnosis :-
A diagnosis of far-sightedness is made by utilizing either a retinoscope or an automated refractor-objective refraction; or trial lenses in a trial frame or a phoropter to obtain a subjective examination. Ancillary tests for abnormal structures and physiology can be made via a slit lamp test, which examines the cornea, conjunctiva, anterior chamber, and iris.In severe cases of hyperopia from birth, the brain has difficulty in merging the images that each individual eye sees. This is because the images the brain receives from each eye are always blurred. A child with severe hyperopia can never see objects in detail. If the brain never learns to see objects in detail, then there is a high chance of one eye becoming dominant. The result is that the brain will block the impulses of the non-dominant eye. In contrast, the child with myopia can see objects close to the eye in detail and does learn at an early age to see objects in detail.
Classification:-
Hyperopia is typically classified according to clinical appearance, its severity, or how it relates to the eye's accommodative status.
There are three clinical categories of hyperopia:-
! Simple hyperopia
Occurs naturally due to biological diversity.
! Pathological hyperopia
Caused by disease, trauma, or abnormal development.
! Functional hyperopia
Caused by paralysis that interferes eye's ability to accommodate.
There are also three categories severity:-
! Low
Refractive error less than or equal to +2.00 diopters (D).
! Moderate
Refractive error greater than +2.00 D up to +5.00 D.
! High
Refractive error greater than +5.00 D.
Other common types of refractive errors are near-sightedness, astigmatism, and presbyopia.
Treatment :-
! Corrective lenses :-
The simplest form of treatment for far-sightedness is the use of corrective lenses, eyeglasses or contact lenses. Eyeglasses used to correct far-sightedness have convex lenses.
! Surgery
There are also surgical treatments for far-sightedness:
! Photorefractive keratectomy (PRK)
Removal of a minimal amount of the corneal surface
! Laser assisted in situ keratomileusis (LASIK)
Laser eye surgery to reshape the cornea, so that glasses or contact lenses are no longer needed.
! Refractive lens exchange (RLE)
A variation of cataract surgery where the natural crystalline lens is replaced with an artificial intraocular lens; the difference is the existence of abnormal ocular anatomy which causes a high refractive error.
! Laser epithelial keratomileusis (LASEK)
Resembles PRK, but uses alcohol to loosen the corneal surface.
Etymology :-
The term hyperopia comes from Greek ὑπέρ hyper "over" and ὤψ ōps "sight" (GEN ὠπός ōpos).
Other common types of refractive errors are near-sightedness, astigmatism, and presbyopia.
in the given picture the upper on e is the diseased eye and the lower one i the diseased eye corrected using lenses .
