Tag: disorders of nervous system

Myopia is a condition in which the light rays entering the eye converge in front of the retina instead of on the retina, for objects that are at a greater distance.

LASIK is a laser eye surgery which helps treat astigmatism, hypermetropia and myopia. It cannot treat colour blindness as it is not caused by lens defect of eye.

Sarcoma is a type of cancer that develops from certain tissues like bone or muscle.

Nyctalopia also called night blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A). It can be described as insufficient adaptation to darkness.
Rhodopsin helps seeing lighted things and is synthesized in the presence of vitamin A (retinol). Its deficiency leads to lack of clear vision during night.

The lens capsule is attached to the ciliary body by a ligament and serves to refract and focus light rays on the retina. Loss of flexibility with age causes presbyopia, characterized by focusing of the image behind the retina. Likewise, too short eyeball causes hyperopia (long-sightedness). In both cases, distant images are clear but the nearby images are blurry and the condition is termed as hypermetropia. 

The lens capsule is attached to the ciliary body by a ligament and serves to refract and focus light rays on the retina. Loss of flexibility with age causes presbyopia, characterized by focusing of the image behind the retina. Likewise, too short eyeball causes hyperopia. In both cases, distant images are clear but the nearby images are blurry and the condition is termed as hypermetropia.

The lens capsule is attached to the ciliary body by a ligament and serves to refract and focus light rays on retina. Loss of flexibility with age causes presbyopia, characterized by focusing of image behind the retina. Likewise, too short eyeball causes hyperobia. In both cases, distant images are clear but the nearby images are blurry and the condition is termed as hypermetropia. This makes option C correct and option D incorrect. On the other hand, myopia or nearsightedness is caused by elongation of eyeball which results in focusing of image in front of retina. Thus, the distant images are blurry but the nearby images are clear. This makes option B incorrect. Cataract is characterized by presence of opaque lens, incapable of transmitting the light rays and is corrected by surgical replacement of lens with artificial lens. This makes option A incorrect. Correct answer is C. 

The lens capsule is attached to the ciliary body by a ligament and serves to refract and focus light rays on the retina. Loss of flexibility with age causes presbyopia, characterized by focusing of the image behind the retina. Likewise, too short eyeball causes hyperopia (long-sightedness). In both cases, distant images are clear but the nearby images are blurry and the condition is termed as hypermetropia.

Myopia is nearsightedness and short-sightedness, is a condition of the eye where the light that comes in does not directly focus on the retina but in front of it, causing the image that one sees when looking at a distant object to be out of focus, but in focus when looking at a close object.
It can be corrected by the use of corrective lenses that have a negative optical power i.e., concave glasses which compensates for the excessive positive diopters of the myopic eye.
So, the correct answer is option A.

Presbyopia is an age-related condition where the eye loses the ability to focus on near objects, requiring bifocal lenses to correct both near and distance vision.