Irritation due to dust particles in the eye is only felt when the eye is openPhotoCredit :

 A foreign body is an object in your eye that shouldn’t be there, such as a speck of dust, wood chip, metal shaving, insect or piece of glass. The common places to find a foreign body are under the eyelid or on the surface of your eye.

When the eyes are kept open we tend to blink at least 15 to 20 times a minute. Every time the eyelid moves over the cornea, both the lid and the cornea get irritated and the discomfort is quite severe.

If the eye is kept closed, there is no movement of the eyelid or cornea and the irritation is much lesser. The cornea (black part of the eye) is the most sensitive part of the external eye and is very rich in nerve fibres.

When the foreign body is either on the cornea or on the eyelid, the corneal nerve fibres are irritated and the resultant discomfort is very severe.

On the other hand, if the foreign body is lodged in the conjunctiva(white part of the eye) the irritation is much less severe because compared with the cornea, the conjunctiva is less sensitive.

Rubbing the eye vigorously when a foreign body is present in the eye can cause damage to the delicate epithelium of the cornea.

A very small foreign body lodged in the cornea can, under rare conditions, be covered by the epithelium of the cornea. In such cases, there will be no irritation at all.

For this to occur, the foreign body should be very small, it should be inert, and should be smooth. Under these conditions, the corneal epithelium can grow over it.

The course of treatment for a foreign object in the eye depends on what the object is, and the degree of contact it has made with the eye.

The best method of removal is to wash out the eye with an eye wash solution or if none is available, tap water. If a tap is not nearby, you can use a water fountain, a hose (using a gentle flow), or a shower. The most important point is to use a generous amount of water to ensure the particle is completely flushed out of the eye.

If you still feel the object in your eye, manual removal is the next option. It’s recommended that you use a tissue or cotton swap while doing this, being very careful not to swipe across the eye. Be sure to look in the opposite direction of where you feel the object (if it’s in your upper eyelid, look down, and vice versa) to protect the cornea.

For larger foreign bodies, or foreign bodies that may have penetrated the eye, seek medical attention immediately.