Foreign Bodies in the Eye

The following text was provided by Claire Smith (Sweet on the forum), who is a nurse and kindly wrote this after completing a teaching session at work as part of her training, aimed at nurses based on the two most common eye complaints presenting to ‘A & E’, being foreign bodies, and conjunctivitis.

Most of us have attended an accident and emergency department at some point with an eye problem, typically due to KC and contact lenses!

Foreign Bodies

Foreign bodies are classified as any particle outside the body.

Despite the natural reflex of the eyelids, particles can often come into contact wth the surface of the eye. There are two types of foreign bodies which are identified below.

Sits on outside of eye or underneath the eyelid.
Actually penetrates or breaks the surface of the eye and becomes lodged within it.

The eye will respond immediately with natural tears if any superficial particle enters it, which usually flushes it away. However vision may be affected if the object becomes lodged in the eye, or damages the cornea or lens.

Common foreign bodies

Dust, sand or debris are common foreign bodies which can enter the eye, but are normally flushed away with the excessive tears. However those that are propelled at high speed by machines, hammering metal objects or grinding present a higher risk of injury, and will need medical attention to ensure that the particle hasn’t embedded itself.

Chemical injuries

Can be sustained by work accidents or household products, such as cleaning chemicals, solvents, cosmetic products or garden products and should be considered an emergency. All chemical burns should be seen in a casualty dept where the chemical involved should be identified, and a ph test taken on arrival. Common burns are identified below.

Acid burns

Are caused by chemicals with a low ph and usually create a haze over the cornea, which should clear over time and cause little damage, as it affects only the very surface of the eye. Common acids causing burns are toilet cleaners, bleach and car battery acid.

Alkaline burns

Are caused by chemicals with a high ph and are the most dangerous type of chemical burn. Alkalis penetrate the surface of the eye and can cause severe injury. Common alkaline burns are caused by substances such as drain cleaners, lime, cement, oven cleaners, ammonia, lye and sodium hydroxide, which can be found in refridgeration equipment. Unfortunately all of these can cause permanent corneal damage despite urgent treatment, so will need to be seen immediately in ‘A & E’.


Have a neutral ph, and while causing severe pain do not normally damage the eye. Pepper spray is a common example.

Signs and symptoms

The following symptoms may be present with a suspected foreign body.

  • Mild to extreme irritation
  • Scratching
  • Burning
  • Soreness
  • Intense pain
  • Redness
  • Watering
  • Decreased vision
  • Light sensitivity
  • Difficulty opening eye


A full vision test is required to assess any changes as well as providing a base line before any treatment. Staff need to know if contact lenses or glasses are usually worn, whether these were used at the time of the incident, and also whether any eye protection was worn.

The eye can then be checked using a slit lamp and the upper lid turned gently upward to ensure that no particle is trapped underneath. If a foreign body is not seen, a fluorescein dye can be used to highlight the area. Some particles can scratch the cornea and be flushed away by tears, but leave a sensation that it is still in contact with the eye.

Superficial foreign bodies are usually easy to remove if seen. A topical anesthetic is used to numb the eye and the particle can be removed using a sterile cotton bud (Do not try this at home! LOL!) Antibiotic eyedrops such as choramphenicol, are then prescribed to reduce the risk of infection as some particles may leave a small scratch on the eye.

Penetrating or intra-ocular foreign bodies are typically removed in the operating theatre using a microscope and equipment designed for working inside the eye. These injuries are often vision threatening and should be seen in hospital immediately.

Chemical injuries or burns need to be flushed immediately with water for at least ten minutes, with whatever is on hand, e.g. running water from a tap or bottled water. Do not remove any contact lenses until this has been done, as removal can cause the chemical to pool under the lens and cause more damage. Most chemical burns damage the surface of the eye, but the severity depends on the chemical involved, how long it had contact with the eye, and indeed how soon after treatment was started.

Some chemicals, such as carbolic acid, do not mix with water, and so cannot be flushed away. A poison control centre would be able to inform staff at the hospital of any treatment needed, which is why it is important that you know what the chemical is before you attend, by maybe taking the label with you to show them. Please do not take the bottle as you may cause a major incident and evacuation process if it is a poisonous substance!!

Lastly, just so that you are aware… it may take up to twenty four hours to determine the seriousness of the burn, and indeed the overall outcome so please do not worry.