Eye Problems

The eye is the sensory organ of vision, the most vital human sense, enabling about 80% of our perception of the world. Vision significantly influences mental and physical development, social relationships, happiness, and satisfaction.

The loss of no other organ is as devastating as the loss of an eye. Folk sayings, oaths, and curses like “my eyes,” “by my eyes,” or “may you go blind” reflect the profound importance of vision.

Nature protects this vital organ well. Eyes are housed in bony sockets, shielded by eyelids, eyebrows, and eyelashes. Tear glands, sebaceous glands, muscles, and blood vessels support and maintain visual function.

“Red eye” or “burning eye” is the most common eye discomfort. Only a small fraction of people with red eyes seek medical help. Redness and a burning sensation are the hallmark signs of conjunctivitis, an inflammation of the eye’s mucous membrane.

Acute conjunctivitis typically begins with itching, tearing, and burning. Often, there’s a sensation of a foreign body in the eye. Symptoms worsen at night when tear production decreases, creating a gritty or sandy feeling in the eyes.

When the lower eyelid is pulled down, the inner eyelid’s mucous membrane appears slightly swollen and bright red. The sclera’s mucous membrane shows dilated blood vessels, visible as wavy red lines extending to the cornea’s edge, giving the eye a red appearance, hence the term “red eye.”

Many experience occasional or persistent visual disturbances, described as spots, shadows, dots, or sparkles in or before the eyes. These are usually transient and harmless, often linked to other conditions where the eye remains healthy.

A medical examination is essential for persistent issues, especially if “dark spots” or “dark patches” appear in part of the visual field, as these may signal serious conditions like brain tumors or hemorrhages.

Black and white spots, especially with dizziness, may occur in older adults after sudden head movements. Age-related changes in cervical vertebrae can narrow blood vessels supplying the brain, causing temporary reduced blood flow and such symptoms.

Sparkling, flickering, or dark patches in half the visual field can occur with migraines, accompanied by severe headaches affecting one side of the head, moving shapes, rainbow colors, light sensitivity, and episodic symptoms that resolve when the headache subsides.

Colored vision, where all objects appear tinted in one color, including colorless ones, is abnormal and always requires medical attention. Yellow vision (xanthopsia) is most common, seen in jaundice or digitalis poisoning (a heart medication). Blue vision is rare, linked to alcohol poisoning or neurosyphilis. Red vision is more frequent, associated with vitreous hemorrhage or snow blindness. Colored vision can follow lens removal surgery or pupil-dilating eye drops, especially when looking at smooth surfaces. Even blind individuals may report seeing colored lights, likely due to stimulation of the brain’s visual center.

Blindness is the loss of vision. Complete blindness is the inability to distinguish light from dark in both eyes, though it may affect only one eye. Blindness is more often caused by conditions acquired after birth. Historically, gonorrheal eye infection, a purulent conjunctivitis with corneal ulcers, was a leading cause, contracted during birth from an infected mother.

Sudden blindness, typically affecting one eye, results from eye injury or blockage in the main artery supplying the retina. If a blood clot, air bubble, fat droplet, or cell clump blocks the artery, retinal cells lose oxygen, causing instant blindness. Acute glaucoma, a sudden increase in eye pressure, can also cause rapid blindness within minutes.

Night blindness, or “chicken blindness,” severely reduces vision in low light, though vision is normal in daylight. Affected individuals complain of symptoms at night or feel lighting is too dim. The most common cause is vitamin A deficiency.

Since normal diets typically provide sufficient vitamin A, night blindness occurs mainly during famine, extreme or poor diets, or rarely in spring due to low vitamin A in winter foods. It can be treated within hours with vitamin A-rich foods or within minutes with vitamin A injections.

The eye distinguishes many colors via specialized retinal cells called cones, sensitive to red, green, and blue. All other colors result from mixing these. If cones for a specific color are absent, that color cannot be distinguished. Acquired or inherited conditions may cause total or partial color blindness.

Color blindness, named after chemist and physicist Dalton who first described it, is called daltonism. Total color blindness is monochromatism. Inability to see red is protanopia, green is deuteranopia, and blue is tritanopia. Red-green color blindness is the most common.