Myopia in the context of "Glaucoma"

Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an animal's ability to recognize small details with precision. Visual acuity depends on optical and neural factors. Optical factors of the eye influence the sharpness of an image on its retina. Neural factors include the health and functioning of the retina, of the neural pathways to the brain, and of the interpretative faculty of the brain.

The most commonly referred-to visual acuity is distance acuity or far acuity (e.g., "20/20 vision"), which describes someone's ability to recognize small details at a far distance. This ability is compromised in people with myopia, also known as short-sightedness or near-sightedness. Another visual acuity is near acuity, which describes someone's ability to recognize small details at a near distance. This ability is compromised in people with hyperopia, also known as long-sightedness or far-sightedness.

Refractive error is a problem with focusing light accurately on the retina due to the shape of the eye and/or cornea. The most common types of refractive error are near-sightedness, far-sightedness, astigmatism, and presbyopia. Near-sightedness results in far away objects being blurry, far-sightedness and presbyopia result in close objects being blurry, and astigmatism causes objects to appear stretched out or blurry. Other symptoms may include double vision, headaches, and eye strain.

Near-sightedness is due to the length of the eyeball being too long; far-sightedness the eyeball too short; astigmatism the cornea being the wrong shape, while presbyopia results from aging of the lens of the eye such that it cannot change shape sufficiently. Some refractive errors occur more often among those whose parents are affected. Diagnosis is by eye examination.

A corrective lens is a transmissive optical device that is worn on the eye to improve visual perception. The most common use is to treat refractive errors: myopia, hypermetropia, astigmatism, and presbyopia. Glasses or "spectacles" are worn on the face a short distance in front of the eye. Contact lenses are worn directly on the surface of the eye. Intraocular lenses are surgically implanted most commonly after cataract removal but can be used for purely refractive purposes.

Blurred vision is an ocular symptom where vision becomes less precise and there is added difficulty to resolve fine details.

Temporary blurred vision may involve dry eyes, eye infections, alcohol poisoning, hypoglycemia, or low blood pressure. Other medical conditions may include refractive errors such as myopia, high hypermetropia, and astigmatism, amblyopia, presbyopia, pseudomyopia, diabetes, cataract, pernicious anemia, vitamin B₁₂ deficiency, thiamine deficiency, glaucoma, retinopathy, hypervitaminosis A, migraine, sjögren's syndrome, floater, macular degeneration, and can be a sign of stroke or brain tumor.

LASIK or Lasik (/ˈleɪsɪk/; "laser-assisted in situ keratomileusis"), commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hypermetropia, and astigmatism. LASIK surgery is performed by an ophthalmologist who uses a femtosecond laser or a microkeratome to create a corneal flap to expose the corneal stroma and then an excimer laser to reshape the corneal stroma in order to improve visual acuity.

LASIK is very similar to another surgical corrective procedure, photorefractive keratectomy (PRK), and LASEK. All represent advances over radial keratotomy in the surgical treatment of refractive errors of vision. For people with moderate to high myopia or thin corneas which cannot be treated with LASIK or PRK, the phakic intraocular lens is an alternative.

Doctor Octopus (Dr. Otto Octavius), also known as Doc Ock for short, is a fictional character appearing in American comic books published by Marvel Comics. The character was created by Stan Lee and Steve Ditko and first appeared in The Amazing Spider-Man #3 (July 1963). He is a highly intelligent, myopic, and stocky mad scientist who sports four strong and durable appendages resembling an octopus's tentacles, which extend from his body and can be used for various purposes. After his mechanical harness became permanently fused to his body during a laboratory accident, he turned to a life of crime, and came into conflict with the superhero Spider-Man. He has endured as one of Spider-Man's most prominent villains, and is regarded as one of his three archenemies, alongside the Green Goblin and Venom. He is the founder and leader of the Sinister Six, the first supervillain team to oppose Spider-Man.

While usually portrayed as a supervillain, Doctor Octopus has also been occasionally depicted as a conflicted antihero and ally of Spider-Man. Following Spider-Man's death in the 2012 storyline "Dying Wish", which saw a dying Octavius swapping bodies with the hero and letting him die in his original body, Octavius was motivated to prove he could be a better Spider-Man. As such, he adopted the Superior Spider-Man alias, introduced in Avenging Spider-Man #15.1 following a cameo in Daredevil vol. 3 #21 (both December 2012), as the fourth predominant main continuity Spider-Man. The Superior Spider-Man possesses all of the original Spider-Man's abilities, memories, and equipment, along with additional gadgets created by Octavius, though he often struggles to live up to his predecessor's legacy and seeks to turn his life around after being a villain for years.