Alkali injuries tend to be much more severe than acid injuries because of their lipophilic nature and their ability to penetrate through the eye. A saponification process also occurs when the dissociated hydroxyl ion acts on the cell membranes causing cellular destruction [21]. Alkalis tend to be a more common source of injury compared to acids. Among alkalis, sodium hydroxide, calcium hydroxide, and ammonium hydroxide are the most common in order of prevalence of injury [13]. Alkali injuries tend to come from plaster, lye, lime, cement, ammonia, and cleaning agents [14]. Magnesium hydroxide, which is the active ingredient in sparkler fireworks can cause both a thermal and alkali injury. Because these agents tend to be dry, using a cotton tip to initially brush the dry product out of the eye is preferred before irrigation.

Treatment following chemical burns is similar in alkali and acid burns. Immediate management following chemical burns is of utmost importance and should theoretically start in the field of injury; variability in time before treatment can greatly determine the extent of damage [22]. Patients can become quickly disoriented due to the resultant blepharospasm, and often need assistance in guidance [23]. The patient should be made to lie down for irrigation of the affected eyes. Irrigant solutions differ in quality when comparing patient comfort and effectiveness in normalizing the pH. Water is not a preferred agent for flushing the eye in these injuries because it is hypotonic and may therefore diffuse across the cornea trapping or pushing the toxins instead of irrigating them [23]. That being said, water should be used in the absence of other irrigating solutions. Buffering capacity solutions when available are preferred; Previn, Diphoterine, or Cederroth Eye Wash solution are far superior in balancing intraocular pH based on testing with experimental models with rabbits eyes [24]. Irrigation should last at least 15 min with use of at least 1000 mls of irrigation solution with confirmation of normalization of pH with litmus strip. A Morgan lens can help direct the irrigation. Topical anesthesia can be very helpful if instilled prior to irrigation. Providers should irrigate the fornices, above and below the eyelids, as well as have the patient look in all directions during irrigation to make sure areas still containing or trapping the chemical are not missed. One should note that the use of ointments is not ideal after a chemical injury as this could potentially trap and prolong the noxious stimulus.

Following irrigation and immediate management the goals in the acute phase are to foster reepithelialization, decrease inflammation, prevent infection, reduce sequela, and prevent further damage [25]. There are different classification systems for chemical injury: Bagley, Dua [26], and Roper-Hall [27]. The median number of days for reepithelialization for patients with grade III–V injuries tends to be approximately 30 days using standard therapy [28]. During this time the cornea may be at risk for desiccation, increased friction from blinking, and exposure keratopathy from eyelid closure defects. While the cornea is rebuilding its epithelial layer, the provider must anticipate the functional deficits of this layer and treat proactively. Treatment in the early phase would include frequent preservative free artificial tears to prevent further erosion of the stroma. Mild chemical burns to the eye can be further managed with topical antibiotic.

Extensive damage, such as with Grade III–V chemical burns, require more substantial treatment and most likely require admission for intensive treatment and monitoring. Use of systemic ascorbic acid and ascorbate drops for chemical burns to the eye has been suggested for over 30 years because of their ability to help collagen production, but few studies exist to fully advocate its use for chemical burns to the eye [29]. Topical citrate has also been recommended as a means to reduce inflammation of the cornea by inhibiting polymorphonuclear leukocytes [30]. An 11-year retrospective review led by Brodovsky found that use of ascorbic acid, ascorbate drops, and citrate led to no benefit for Grade I–II burns, clinical benefit in patients with Grade III burns, and unclear effect for Grade IV burns [31]. Because chemical burns may cause shrinkage of the collagen fibers in the cornea, intraocular pressure must also be monitored in the early stages of treatment as 22% of patients with chemical burns develop secondary glaucoma, often requiring oral carbonic anhydrase inhibitors [19]. A study by Panda et al. found that using topical autologous platelet-rich plasma in the form of eyedrops for patients soon after injury can safely reduce the number of days needed for re-epithelialization due to the presence of growth factors in plasma [28].

Topical steroids are also used in the early stages of treatment to reduce inflammation and the release of collagenases and proteases. Steroids may be beneficial particularly in the early stages of treatment, though there is concern that prolonged and extensive use may prevent sufficient collagen production that can lead to cornea/scleral melting; concomitant use with topical vitamin C can help prevent this [32]. Cycloplegics such as homoatropine are also indicated for moderate-to-severe chemical burns, though cycloplegics with vasoconstrictive properties should be avoided. Cycloplegics will reduce pain and the risk of iris lens synechiae [33]. One experimental form of treatment not fully tested in humans is the use of oral tetracyclines during the recovery period due to their ability to inhibit metalloproteinases and collagenase activity [34].

Surgical management if required usually follows in the weeks following the insult. There are many relatively newer therapies available for treatment including amniotic membrane transplantation, limbal stem cell transplantation, corneal transplantation, and keratoprosthesis. Immediate therapy in the acute phase can include tenonplasty if warranted in severe burns. This is done by first removing necrotic conjunctiva and advancing Tenon’s tissue from the orbital region to the limbus and securing it to the sclera to provide vascularization to the damaged region to help prevent perforation [35]. Amniotic membrane transplantation (AMT) for corneal chemical burns, first studied by Meller et al., found that the use of AMT within 2 weeks of injury for mild-to-moderate burns can rapidly restore corneal and conjunctival surfaces [36]. For severe burns, AMT was able to reduce limbal stromal inflammation and restore the conjunctival surface, and prevent symblepharon formation, it could not fully prevent limbal stem cell deficiency [36]. In these cases of severe burns, a limbal stem cell transplant may be necessary [37]. A recent study has shown that autologous limbal stem cells can be harvested from the contralateral eye and grown ex vivo on fibrin media, allowing transplantation that results in transparent self-renewing epithelium of the damaged eye in 76.6% of patients [38]. Usually these two modalities of treatment can be used together with superior results for severe burns when limbal stem cell deficiencies can be anticipated [39].

If the aforementioned therapies do not produce results allowing for meaningful recovery of vision, there are two options left for last resort, corneal transplantation and keratoprothesis. Corneal transplantation has a higher rate of rejection in chemical burns and requires large diameter transplants for limbal stem cell transfer [40]. If patients do not qualify for transplant or have repeatedly failed transplant, a Boston Type 1 keratoprothesis may ultimately be an option for therapy. A recent 7-year retrospective study shows that visual acuity of ≥20/200 using the prosthesis is achieved in 50% of patients and total device retention after 7 years is 67% [41]. The most common complications in order of prevalence were Retro-prosthetic membrane formation, glaucoma surgery, retinal detachment, and endophthalmitis [41] following keratoprosthesis. Further design and technological revisions may help reduce these complications in the years to come.

Corneal abrasion is one of the more common complaints of patients, representing approximately 24.3% of patients who present to the emergency room for ophthalmological complaints [42]. It occurs when the corneal epithelium is disrupted from a variety of injuries. As with other ocular injuries, these injuries tend to happen more often in the workplace or during sports activities. Common etiologies of corneal abrasions include fingernails, sports equipment, make-up brushes, and airbags. Children represent the most common source of fingernail injury, as patients are often parents who become injured while holding a small child [43]. Airbag deployment presents a particular challenge because it may also be associated with a high-energy blunt force as well as alkali injury [44]. In the hospital setting, corneal abrasion can happen more often in unconscious patients in the ICU or patients receiving non-ocular surgery as a complication of accidental injury during the surgery [45]. Patients often present with pain, tearing, blurred vision, photophobia, red eye, and foreign body sensation. Often times these injuries are associated with corneal lacerations and foreign bodies; and as with any mechanical injury, careful attention must be paid to the risk of an open globe. Prognosis is largely dependent on the size of the defect and depth of injury and involvement of Bowman’s layer.

Work-up for such injuries includes careful investigation regarding the mechanism of the injury. High-energy forces such as with airbags, projectiles, and punches should alert the physician in seeking other sequelae of injury both ocular and non-ocular. Because of the severe pain and photophobia associated with abrasions, work-up must often begin with the use of anesthetic eye drops such as tetracaine or proparacaine. Topical anesthetics should never be given for outpatient use. Abrasions may be immediately visible to the naked eye as they may present with a haze due to the reduced light reflex. Using fluorescein dye will allow the examiner to see a more enhanced demarcation of the abrasion. All patients should have a full ophthalmologic exam to rule out other injuries, particularly to the anterior chamber and retina. A Seidel test can be used to determine if there is a leak from the anterior chamber indicating an open globe.

Corneal foreign bodies usually occur when the cornea comes in contact with a high-speed small projectile. These injuries therefore often occur in the workplace with metal workers and with patients who use power tools. Patients tend to be overwhelmingly male and often have a history of not using eye protection. Interestingly, a study from Australia found that 45% of patients presenting with metallic foreign bodies actually did use eye protection, but it is unclear if mechanism of injury occurred due to failure of the eye protector apparatus, or operator failure in using the proper eye protection needed for the job [50]. Broadly, foreign bodies can be divided into two classes, organic and inorganic. Prevalence between the two categories often depends on the location of the hospital or clinic in relation to the industry but foreign bodies tend to overwhelmingly be metal in nature [51]. Organic foreign bodies carry the increased risk of infection as they typically carry with them more bacteria and fungi. Inorganic foreign bodies such as glass, stone, plastic, and certain metals are frequently benign as they often do not induce inflammation. Of the metals, iron and copper tend to be the most troublesome due to their staining and ability to induce inflammation. Metal foreign bodies tend to have lower rates of infection as they are often heated when they become projectile. Overall, most foreign body injuries tend to be benign and not associated with significant morbidity. In a study of 288 patients with superficial corneal metallic foreign bodies, only 1 patient had concomitant corneal laceration [52]. Regardless, careful attention must be paid to the history and physical in determining the force of the projectile involved and the risk of an open globe (Fig. 2.2).

Patients with a corneal foreign body typically present with pain, foreign body sensation, tearing, red eye, and sometimes photophobia. Whether a patient presents with blurred vision is largely dependent on whether the foreign body is along the visual axis. The physical exam must focus on eliminating the possibility of intraocular injury and further ocular damage. If imaging is required, one should not use MRI if a metallic foreign body is suspected. As with corneal abrasions, fluorescein can help define the borders of the injury. A Seidel test can be used to determine if there is a leak from the anterior chamber. Topical anesthetics may have to be used early in the exam in order in increase patient comfort and compliance with the exam as well as to facilitate removal.

A corneal laceration occurs when the cornea is cut, often with a sharp object, leaving a defect that can be partial or full thickness. Among corneal injuries, corneal laceration can often represent one of the more severe injuries due to comorbidities associated with further intraocular injury. For children, they represent a common cause of amblyopia and ocular morbidity. Approximately 86% of penetrating wounds to the eye occur in males [58]. Full thickness wounds present a particular challenge because of the increased risk of intraocular infection and often require early surgical repair.