Visual acuity is the clearness or sharpness of the eye vision and it depends upon the natural ability of the brain to see, understand and express the meaning of the object before it and depends upon the acuteness of the retinal focus within the eye.
Visual acuity is measured under a controlled position, area, size of the things and distance. It is meant to see the visual processing system for optimization and standardization of the condition. The distance is allowed in such a way that the lens attempts to focus. …

Macula: Macula of the retina of the human eye is also called as Central Retina or Macula Lutea (from the Latin macula, meaning “a spot”, and lutea meaning “yellow”). It is also called as ‘bull’s eye in the center of the retina.’
Yellow coloured macula : Yellow colour of the macula is due to the lutein and zeaxanthin, which are carotenoids and absorbed from the diet. The yellow colour of the macula absorbs the excess radiation of ultraviolet rays from the sun and thereby protects the retina …

Blindness is described as the condition lacking in visual perception. It may be due to neurological or physiological factors. Vision loss is differentiated in various scales.
Total blindness is described as the complete lack of visual sight perception and other wise it is called as no light perception(NLP).
Blindness occurs in the following diseases:
1. Temporal arteritis (head ache, jaw claudication, malaise)
2. Conjunctival ulcer or trauma
3. Cataract (gradual, opaque lens)
4. Glaucoma (rapid, pain)
5. Migraine (head ache, photophobia, nausea)
6. Optic neuritis (eg. in multiple sclerosis)
7. Senile macular degeneration (gradual, elderly)
8. Head trauma (eg. optic canal haemotoma)
9. Acute chorioretinitis
10. Optic nerve compression
11. Keratitis (pain, red …

Black or dark circle under eyes occur due to various reasons. It may be caused by several reasons including hereditary factor, fatigue, insufficient sleeping condition, nasal congestion, chronic atopic eczema, stress and because of aging. Eye lid swelling may also cause dark circles in the eye lids. Excessive pigmentation due to melanin accumulation and exposure to constant sun rays also cause dark circles.
Poor nutrition also leads to black circles under the eyes. Taking proper diet with necessary vitamins and minerals are the first step to cure the darkness and second …

Chalazion is a small sac containing fluid or it is a cyst on the inside of the eyelid. It is an inflammatory granuloma of a meibomian gland. This chalazion is otherwise called a meibomian cyst usually affecting the upper eye lid. When one of the meibomian gland ducts is obstructed or blocked chalazion appears. This gland is very important in keeping the eyes moist by its secretion of oily substance. The human eye lid is having several layers of tissues and chalazions are formed in one of these layers namely …