Vision Defects and Eye Conditions

Yes, it is correct. Graves' ophthalmopathy due to thyrotoxicosis does not involve the uveal tract.

Eye irritation can be avoided by cutting onions under running water or submerging the onions in a basin of water. Leaving the root end intact also reduces irritation as the onion base has a higher concentration of sulphur compounds than the rest of the bulb.

Cataract is a condition in which the eye lens becomes progressively opaque resulting in blurred vision.

Excessive tearing, also known as epiphora, is due to a disruption in the balance between tear production and tear loss. Numerous etiologies lead to an excess of tears, and there are a number of ways to diagnose and treat this condition.

Keratoconus is degeneration of the structure of the cornea. The cornea is the clear tissue covering the front of the eye. The shape of the cornea slowly changes from the normal round shape to a cone shape.

Rhodopsin, also known as visual purple, is a biological pigment in photoreceptor cells of the retina that is responsible for the first events in the perception of light. Night blindness or nyctalopia occurs in persons with severe vitamin A deficiency. Non-availability of this vitamin leads to the decreased formation of rhodopsin.

Hemianopia or hemianopsia is a type of anopsia where the decreased vision or blindness takes place in half the visual field of one or both eyes. In most cases, the visual field loss respects the vertical midline. The most common causes of this damage include stroke, brain tumor and trauma.

Astigmatism occurs when the curvature of the lens is uneven.

Ophthalmologist is the doctor of eyes.

It is a disease found in the eyes and can be corrected by the surgical removal of clouded lens.

Glaucoma is an eye condition caused by increased intraocular pressure (fluid pressure inside the eye), damaging the optic nerve. Cataract is lens clouding, ophthalmic neonatorum is infant eye infection, and conjunctivitis is inflammation of the eye membrane - none involve pressure elevation.

An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances. Astigmatism is a state in which one cannot see both the vertical and horizontal lines simultaneously.

 Glaucoma is a multi-factorial, complex eye disease with specific characteristics such as optic nerve damage and visual field loss. While increased pressure inside the eye (called intraocular pressure or IOP) is usually present, even patients with normal range IOP can develop glaucoma.

Endophthalmitis (infection), Posterior Capsule Opacification (secondary cataract), and Retinal Detachment are known complications of cataract surgery. Epilepsy is a neurological disorder involving seizures and has no causal relationship with cataract surgery.

In presbyopia, there is decrease in the accommodation power of the eye.