CHAPTER 22: Ophthalmology

OCULAR EXPOSURE

The surface of the eye needs to stay well lubricated or it can lead to vision-threatening complications in the ICU

PATHOPHYSIOLOGY

• Normal ocular surface protective mechanisms include tear production, intact corneal sensation, blinking, and complete eyelid closure

• Impaired protective mechanisms result in corneal exposure and drying

• Corneal “dryness” (subclinical epithelial breakdown) may progress to corneal abrasion, ulceration, infection, scarring, thinning, and/or perforation if untreated

CLINICAL MANIFESTATIONS

• Risk factors for corneal exposure include loss of protective mechanisms due to deep sedation, neurologic impairment, or eyelid abnormality; overhead warmers; treatments causing air to blow over the eyes

• Risk increases with poor eyelid closure: Low risk with eyelids that close completely, increasing with white sclera showing, highest with cornea or underlying iris showing

• Eye exam may reveal conjunctival redness or swelling, corneal haze or opacity, blunted red reflex

DIAGNOSTICS

• Slit lamp biomicroscope exam and fluorescein staining may reveal punctate erosions, corneal abrasion, opacity (ulcer), thinning, or perforation

MANAGEMENT

• Prophylaxis for at-risk patients (e.g., intubated and sedated) is critical:

  • ✓ Lubricating eye ointment (Lacri-lube ointment which consists of mineral oil and white petrolatum) with frequency according to eyelid position

  • ✓ Closed lids every 6–8 hours, sclera showing every 4–6 hours, cornea showing every 2–4 hours; the frequency of ointment administration may be reduced if the eye and ointment are then covered with a piece of non-sticky plastic wrap (e.g., saran wrap) to form a “moisture chamber”

  • ✓ Artificial tear drops evaporate quickly and are not useful

• Prompt ophthalmology consultation for red conjunctiva, corneal haze or opacity, or if the cornea is visible due to incomplete eyelid exposure in an at-risk patient

• Antibiotic ophthalmic ointment (erythromycin, polysporin) if there is corneal epithelial staining with fluorescein

• Complicated cases may require tarsorrhaphy (suturing of eyelids), bandage contact lens, corneal gluing, or emergent corneal transplantation

CORNEAL CLOUDING AND GLAUCOMA

The cornea should always be clear with visible iris details and a bright red reflex, and any opacity, whether diffuse or focal, is a sign of serious eye disease.

Glaucoma is irreversible optic nerve damage due to increased intraocular pressure.

DIFFERENTIAL DIAGNOSIS OF CORNEAL CLOUDING IN AN INFANT

• Trauma: Forceps injury, corneal perforation with amniocentesis

• Infection: Syphilis, rubella, HSV, bacterial ulcer

• Infantile glaucoma: Associated with enlarged eye (buphthalmos)

• Corneal or limbal dermoid, associated with Goldenhar syndrome

• Anterior segment dysgenesis: Peters anomaly (central corneal opacity), sclerocornea

• Corneal dystrophy: Congenital hereditary endothelial dystrophy (CHED), congenital hereditary stromal dystrophy (CHSD)

• Metabolic: Mucopolysaccharidoses (Hurlers, MPS IH; Type IV, mucolipidoses), cystinosis, tyrosinemia

EPIDEMIOLOGY AND ETIOLOGY

Primary Glaucoma

• Primary infantile glaucoma (congenital glaucoma): 1:10,000–1:15,000; 90% sporadic

• Caused by developmental defect in the structure of the anterior chamber

• Associated systemic syndromes ...