Alkali or Strong Acid Burns to the Eye Should Be Irrigated Continuously for at Least

Chemical exposure to any part of theeye or eyelid may result in a chemical eye burn.Chemical burns represent a small percentage ofeye injuries. Someburns to the face involve at least oneeye. Although many burns result in only minor discomfort, everychemical exposure or burn should be taken seriously.

Chemical injuries to the eye represent one of the true ophthalmic emergencies. While almost any chemical can cause ocular irritation, serious damage generally results from either strongly basic (alkaline) compounds or acidic compounds. Alkali injuries are more common and can be more deleterious. Bilateral chemical exposure is especially devastating, often resulting in complete visual disability. Immediate, prolonged irrigation, followed by aggressive early management and close long-term monitoring, is essential to promote ocular surface healing and to provide the best opportunity for visual rehabilitation. Although many burns result in only minor discomfort, every chemical exposure or burn should be taken seriously. Permanent damage is possible and can be blinding and life-altering.

The severity of a burn depends on what substance caused it, how long the substance had contact with the eye, and how the injury is treated. Damage is usually limited to the front segment of the eye, including the cornea, (the clear front surface of the eye responsible for good vision, which is most frequently affected), the conjunctiva (the layer covering the white part of the eye), and occasionally the internal eye structures of the eye, including the lens

The eyelids close quickly in a reflex reaction to protect the eyes from harm. However, irritating or harmful chemicals still sometimes get onto the surface of the eye, causing burns. The most dangerous chemical burns involve strong acids or alkali. Alkali burns tend to be more serious than acid burns. Alkali substances include lye (caustic soda), which is found in many drain cleaners. Burns may involve liquids, which splash, or, less commonly, powdered material, which can blow into the eyes.

Severe chemical burns of the transparent dome on the front surface of the eye (cornea), especially alkali injuries, can lead to scarring, perforation of the eye, and blindness.

Burns to the eye are very painful. Because the pain is so great, a person tends to keep the eyelids closed. Closed eyelids keep the substance against the eye for a prolonged period, which may worsen the damage.

The blink reflex usually causes the eye to close in response to heat. Thus, thermal burns tend to affect the eyelid rather than the conjunctiva or cornea. Thermal burns of the conjunctiva or cornea are usually mild and cause no lasting damage to the eye.

Treatment

• Immediate flushing of the eye with water
• Continued flushing of the eye with saline by medical personnel

Chemical burns

A chemical burn of the eye is treated immediately, even before medical personnel arrive. The eye is opened and flushed (irrigated) with water or saline. When burns are caused by strong acids or alkali or other severely caustic substances, the eye should be irrigated continuously for 30 to 120 minutes. Irrigation can be continued where it began, in an ambulance, or in an emergency department. Because pain may make it difficult for the person to keep the injured eye open, another person may have to hold the eyelid open while the eye is irrigated.

Chemical burns represent 7%-10% of eye injuries. About 15%-20% of burns to the face involve at least one eye.

The acidity or alkalinity, called the pH, of a substance is measured on a scale from 1-14, with 7 indicating a neutral substance. Substances with pH values less than 7 are acids, while numbers higher than 7 are alkaline; the higher or lower the number, the more acidic or basic a substance is and the more damage it can cause. Alkali

Alkali agents are lipophilic and therefore penetrate tissues more rapidly than acids. They saponify the fatty acids of cell cell membranes, penetrate the corneal stroma and destroy proteoglycan ground substance and collagen bundles. The damaged tissues then secrete proteolytic enzymes, which lead to further damage.

Acid burns result from chemicals with a low pH and are usually less severe than alkali burns, because they do not penetrate into the eye as readily as alkaline substances. The exception is a hydrofluoric acid burn, which is as dangerous as an alkali burn. Acids usually damage only the very front of the eye; however, they can cause serious damage to the cornea and also may result in blindness. Acids

Acids are generally less harmful than alkali substances. They cause damage by denaturing and precipitating proteins in the tissues they contact. The coagulated proteins act as a barrier to prevent further penetration (unlike alkali injuries). The one exception to this is hydrofluoric acid, where the fluoride ion rapidly penetrates the thickness of the cornea and causes significant anterior segment destruction.

Primary prevention

Since the majority of injuries occur at work, protective eye shields are mandatory when handling potentially corrosive substances. However, even protective goggles are no match for chemicals under high pressure.

Early signs and symptoms of a chemical eye burn are:

• Pain
• Redness
• Irritation
• Tearing
• Inability to keep the eye open
• Sensation of something in the eye
• Swelling of the eyelids
• Blurred vision

Chemical Eye Burn Treatment

Self-Care

For all chemical injuries, the first thing you should do is immediately irrigate the eye thoroughly. Ideally, specific eye irrigating solutions should be used for this, but if none are available regular tap water will do just fine.

• Begin washing your eye before taking any other action and continue for at least 10 minutes. The longer a chemical is in your eye, the more damage will occur. Diluting the substance and washing away any particles that may have been in the chemical are extremely important.
• Ideally, in a work setting, you would be placed in an emergency eyewash or shower station and your eye washed with sterile isotonic saline solution. If sterile saline is not available, use cold tap water.
• If you are at home and do not have special eye wash, step into the shower with your clothes on to wash out your eye.
• Even though it may be uncomfortable, open your eyelids as wide as possible as you rinse them out.
• If an alkali (e.g., drain cleaner) or hydrofluoric acid burn has occurred, continue washing until a doctor arrives or you have been taken to a hospital's emergency department.

Early irrigation is critical in limiting the duration of chemical exposure. The goal of irrigation is to remove the offending substance and restore the physiologic pH. It may be necessary to irrigate as much as 20 liters to achieve this. To optimize patient comfort and ensure effective delivery of the irrigating solution, a topical anesthetic is generally administered. Of course, early irrigation is paramount to limiting the duration of chemical exposure. If clean water is available at the site of injury and a standard irrigating solution is not, then the eyes should immediately be washed out with water.

Standard Treatments

Antibiotics- A topical antibiotic ointment like erythromycin ointment four times daily can be used to provide ocular lubrication and prevent superinfection. Stronger antibiotics (e.g. a topical fluoroquinolone) are employed for more severe injuries.

Cycloplegic agents such as atropine or cyclopentolate can help with comfort.
Artificial tears- and other lubricating eye drops, preferably preservative free, should be used generously for comfort.

Steroid drops- In the first week following injury, topical steroids can help calm inflammation and prevent further corneal breakdown.[14] In mild injuries, topical prednisolone(Predforte) can be employed four times daily. In more severe injuries, prednisolone can be used every hour. After about one week of intensive steroid use, the steroids should be tapered because the balance of collagen synthesis vs. collagen breakdown may tip unfavorably toward collagen breakdown.

Ascorbic acid- is a cofactor in collagen synthesis and may be depleted following chemical injury. Ascorbic acid can be used as a topical drop (10% every hour) or orally (two grams, four times daily in adults). In one study, severe alkali burns in rabbit eyes were associated with reduced ascorbic acid levels in the aqueous humor. This reduction correlated with corneal stromal ulceration and perforation. Systemic administration of Vitamin C helped promote collagen synthesis and reduce the level of ulceration. Care must be taken in patients with compromised renal function because high levels of Vitamin C are potentially toxic to the kidneys. Recovery depends on the type and extent of

Recovery depends on the type and extent of injury.

• Chemical irritants seldom cause permanent damage.
• Recovery from acid and alkali burns depends on the depth of the injury.

The 4 grades of burns are

• Grade 1: You should recover fully.
• Grade 2: You may have some scarring, but your vision should recover.
• Grade 3: Your vision will usually be impaired to some degree.
• Grade 4: Damage to your vision likely will be severe.

Grade I Topical antibiotic ointment (erythromycin ointment or similar) four times a day

• Prednisolone acetate 1% four times a day
• Preservative free artificial tears as needed
• If there is pain, consider a short acting cycloplegic like cyclopentolate three times a day

Grade II Topical antibiotic drop like fluoroquinolone four times daily

• Prednisolone acetate 1% hourly while awake for the first 7-10 days. Consider tapering the steroid if the epithelium has not healed by day 10-14. If an epithelial defect persists after day 10, consider progestational steroids (1% medroxyprogesterone four times daily)
• Long acting cycloplegic like atropine
• Oral Vitamin C, 2 grams four times a day
• Doxycycline, 100 mg twice a day (avoid in children)
• Sodium ascorbate drops (10%) hourly while awake
• Preservative free artificial tears as needed
• Debridement of necrotic epithelium and application of tissue adhesive as needed

Grade III As for Grade II

• Consider amniotic membrane transplant/Prokera placement. This should ideally be performed in the first week of injury. Experienced surgeons have emphasized placement of the amniotic membrane to cover the palpebral conjunctiva by suturing to the lids in the operating room, not just covering the cornea and bulbar conjunctiva.

Grade IV As for Grade II/III

• Early surgery is usually necessary. For significant necrosis, a Tenonplasty can help reestablish limbal vascularity. An amniotic membrane transplant is often necessary due to the severity of the ocular surface damage.

With severe chemical burns, patients should initially be followed daily. If there is concern for compliance with medication or if the patient is a child, one should consider inpatient admission. Once the health of the ocular surface has been restored, follow up can be spread apart. However, even in the healthiest appearing eyes, patients need long term monitoring for glaucoma and dry eye .

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