INTRODUCTION
Ophthalmology has evolved substantially over the past decade. Innovations in surgical techniques and tissue banking as well as developments in ophthalmic surgical devices and implants, allow an increasingly sophisticated approach to ophthalmic surgery. Advances in imaging the microanatomy of the eye facilitate diagnosis and guide treatment. Nonetheless, the majority of diagnoses in ophthalmology can be made after a targeted history and careful examination without the need for sophisticated equipment.
Evaluation of the eye and its adnexa requires a good history, assessment of visual function and physical examination of the eyes. Occasionally, special examinations may be required to identify specific ocular disorders or to establish the presence of associated systemic disease.
The basic equipment required for an eye examination by a nonophthalmologist includes the following: (1) a visual acuity chart, (2) a handheld flashlight, (3) an ophthalmoscope, and (4) a tonometer.
The basic medications required for an eye examination are (1) a local anesthetic such as proparacaine 0.5% or tetracaine 0.5%; (2) fluorescein strips; and (3) dilating drops, such as phenylephrine 2.5% or tropicamide 0.5%-1%.
In addition to eliciting a chief complaint, determining whether visual loss is monocular or binocular, central or peripheral, and painful or painless is important.
Prior ophthalmic history (including known ophthalmic conditions, prior eye surgery or trauma, history of contact lens use, and relevant family history) should be obtained.
A review of past medical history and all medications should be included as well.
Central visual acuity, using the patient’s glasses if available, should be determined in all patients. The Snellen chart is most commonly used. The patient faces the test chart at a distance of 6 m (20 ft). Each eye should be tested separately. Visual acuity corresponds to the smallest line the patient can read. The patient who is unable to read the largest letter on the chart (typically a 20/200 letter) should be moved progressively closer until that character can be read and that distance recorded in the chart. If no letters are recognizable, the patient should be tested for the ability to count fingers, see hand motion or perceive light. If a vision chart is not readily available, the ability to read small print or a name badge can provide useful information. Preschool children or illiterates can be tested with the E chart or Allen picture chart.
Confrontation visual fields can be used to detect gross visual field defects such as quadrantanopia, hemianopia, or severe visual field constriction. With one eye occluded, the patient is asked to fixate on the examiner’s face and detect finger count or hand motion in each quadrant. Formal visual field testing (perimetry) is used to more carefully examine the central and peripheral visual fields. The technique is performed separately for each eye and measures the function of the retina, the optic nerve and intracranial visual pathway. Perimetry relies on subjective patient responses so results will depend on the patient’s alertness and cooperation. Several methods are used to assess visual field functions, including the tangent screen, Goldmann perimetry, and computerized automated perimetry.
Ocular motility should be assessed in all positions of gaze. One should also observe the patient for random eye movement and assess the alignment of the eyes when the patient is looking straight ahead. The position of the light reflection from a penlight (“reflex”) on the cornea is at the same point in each eye when the eyes are properly aligned. The oculocephalic reflex (doll’s head) can be tested. The upward rotation of the cornea in response to resistance to forced eyelid closure (Bell phenomenon) should be noted when clinically appropriate.
Examination of the pupils should be performed before any dilating drops are instilled. Both the direct and consensual light reflex should be assessed. The pupils should constrict with accommodation. The size of the pupils should be noted in light and dark conditions and any difference in size (anisocoria) should be recorded. Irregular pupils may indicate traumatic, postsurgical, neurological, or congenital defects. In hospitalized patients and those with neurological disorders requiring monitoring of pupillary reaction to assess clinical status, pupils should be dilated with discretion and only with short-acting mydriatics.
The eyelids, conjunctiva, cornea, sclera, and lacrimal apparatus should be evaluated. Unusual prominence of the globes (proptosis), abnormal eyelid position and the inability to fully close eyelids are important features that should be documented. Eversion of the upper eyelid to enable inspection of the hidden conjunctival surface should be performed when appropriate. The conjunctiva is inspected for anatomic defects, foreign bodies, lacerations, inflammation, discharge, tearing, dryness, or other abnormalities. In patients who are unconscious, the presence or absence of Bell phenomenon (upward rotation of the cornea during sleep) may be an important measure of neurological function. Corneal sensation should be tested before anesthetic drops are used.
A direct ophthalmoscope focused on the ocular surface can provide magnification for the examination. A magnifying glass and a handheld flashlight can also be used. Shining a light across the eye from the lateral to medial aspects and noting whether or not the nasal iris is shadowed can assess the depth of the anterior chamber. The presence of shadowing may indicate a narrow anterior chamber angle requiring special precautions if dilating drops are to be used.
Ophthalmoscopy is important for the diagnosis of both ocular and systemic conditions and can provide critical information in neurologic and neurosurgical contexts. In most instances, the optic nerve head can be clearly seen without dilating the pupils. When describing the optic nerve, it is important to note any nerve head edema and the cup-to-disc ratio. Vessel caliber, tortuosity, arteriovenous nicking, and the presence of retinal hemorrhages are additional findings that can aid in diagnosis. In hospitalized patients with neurologic and neurosurgical disorders, dilation of the pupils should be performed with discretion.
Tonometry measures intraocular pressure (IOP). The most common instruments used are the Tono-Pen and the Goldmann applanation tonometer. The normal intraocular pressure varies between 10 and 20 mm Hg. IOP measurements can vary slightly with corneal thickness.
Efforts should be made to determine if the decrease in visual acuity is unilateral or bilateral, painful or painless, persistent or transient, recent or chronic, isolated or associated with other symptoms. Unilateral acute painful loss of vision may be due to angle-closure glaucoma, endophthalmitis, or uveitis. Painless unilateral loss of vision is often caused by ischemic optic neuropathy, optic neuritis, central retinal artery or vein occlusion, retinal detachment, vitreous hemorrhage or retinal hemorrhages. Transient painless unilateral loss may be due to retinal migraine or amaurosis fugax. Hemispheric strokes are often responsible for visual field loss with preservation of the central visual acuity.
Disturbances in vision include image distortion, light sensitivity (photophobia), color change, spots before the eyes, visual field defects, night blindness, momentary loss of vision, or halos around lights. Distortion of normal shape (metamorphopsia) is most commonly caused by macular lesions. Photophobia can be due to corneal inflammation, iritis, ocular albinism, or aniridia. Toxicity from systemic medications such as digoxin and certain retinal conditions can cause the patient to complain of abnormally colored vision (chromatopsia). Patients with vitreous opacities or intraocular inflammation may report floating spots in their vision, even if retinal tears and detachment have to be ruled out as a cause. Visual field defects may be due to lid edema, retinal and optic nerve lesions, visual pathway lesions, or cortical abnormalities. Night blindness may be genetic (as in patients with retinitis pigmentosa) or acquired. Important causes of acquired night blindness include vitamin A deficiency, glaucoma, optic atrophy, cataract, or retinal degeneration. Transient loss of vision may imply impending cerebrovascular accident or partial occlusion of the internal carotid artery. Colored halos around lights can be caused by elevated intraocular pressure, most commonly due to acute angle-closure glaucoma. Incipient cataract or incorrect refractive error can cause colorless halos around point light sources.
Diplopia can be constant or intermittent, sudden or gradual, painful or painless, horizontal or vertical. It may occur only in certain gaze positions. It is important to first determine if the diplopia is monocular or binocular. Binocular diplopia is only present when both eyes are open and disappears when either eye is closed. Binocular diplopia is most often due to misalignment of the eyes from extraocular muscle dysfunction or neurologic abnormalities. Monocular diplopia (multiple images in a single eye) occurs with refractive error, lenticular changes, macular lesions, malingering, or conversion reactions.
Ocular pain may result from corneal lesions, inflammation, rapid increase in intraocular pressure, anterior uveitis, cyclitis, scleritis, or optic neuritis. Other causes of pain include inflammation of the orbital contents, tumors in the orbit and dacryocystitis (lacrimal sac inflammation). Eyelid pain and irritation can also arise from infections of the meibomian glands and the glands of Zeis and Moll.
Acute redness (injection) of the eye not associated with trauma is caused by conjunctivitis, acute anterior uveitis, acute angle-closure glaucoma, corneal infection or corneal abrasion (Table 37–1). Subconjunctival hemorrhage may also present as a red eye but this is usually painless and otherwise asymptomatic. Conjunctivitis from bacterial, chlamydial, viral, or allergic causes is a frequent cause of red eye. Nonspecific irritation from exogenous agents or a foreign body can also cause redness. Chemical and thermal injuries cause similar findings. “Dry eye” or ocular surface anomalies can cause redness, a foreign-body sensation, and variable degrees of decreased vision.
| Acute Conjunctivitis | Acute Iritis1 | Acute Glaucoma2 | Corneal Trauma or Infection | |
|---|---|---|---|---|
| Incidence | Extremely common | Common | Uncommon | Common |
| Discharge | Moderate to copious | None | None | Watery or purulent |
| Vision | No effect on vision | Slightly blurred | Markedly blurred | Usually blurred |
| Pain | None | Moderate | Severe | Moderate to severe |
| Conjunctival injection | Diffuse; more toward fornices | Mainly circumcorneal | Diffuse | Diffuse |
| Cornea | Clear | Usually clear | Steamy | Change in clarity related to cause |
| Pupil size | Normal | Small | Moderately dilated and fixed | Normal |
| Pupillary light response | Normal | Poor | None | Normal |
| Intraocular pressure | Normal | Normal | Elevated | Normal |
| Smear | Causative organisms | No organisms | No organisms | Organisms found only in corneal ulcers due to infection |
Ocular discharge may be described as watery, mucopurulent, purulent, or crusting of the lid margins. When watery discharge is not associated with redness or pain, it may be due to excessive tear production or obstruction of the lacrimal outflow passages. Watery discharge with photophobia, pain, or irritation indicates possible keratitis or keratoconjunctivitis. Purulent or mucopurulent discharge is a sign of bacterial infection, severe inflammation of the conjunctival surface, or bacterial infection of the lacrimal sac or canaliculus. Pseudomonas or Haemophilus species involvement is common. When the discharge forms mucoid strings, it is characteristic of allergic disorders involving the conjunctiva (vernal conjunctivitis) or dry eye syndrome.
For unilateral swelling, the cause is often a stye or chalazion. Bilateral swelling suggests blepharitis or allergic dermatitis. Systemic diseases associated with water retention, hyperthyroidism, or hypothyroidism can also cause swelling or puffiness of the eyelids.
The most common cause of both unilateral and bilateral exophthalmos (proptosis) is hyperthyroidism. Other etiologies include tumors of the orbit.
Strabismus results from misalignment of the eyes due to muscle imbalance. Ocular deviations may be lateral (exotropia), medial (esotropia), upward (hypertropia), or downward (hypotropia). Binocular diplopia is not a frequent complaint in congenital strabismus. Full ocular motility is intact in the majority of strabismus cases.
A white pupil in a child indicates a serious eye disorder. The most frequent cause of leukocoria is congenital cataract, which requires urgent management to prevent amblyopia. Other causes include retinoblastoma, retinopathy of prematurity, toxocariasis, persistent hyperplastic primary vitreous, vitreous hemorrhage, retinal detachment, retinal dysplasia, incontinentia pigmenti, Coats disease, and Norrie disease.
Patients may present with other symptoms such as burning, itching, gritty, and foreign-body sensations, or a “sandy” feeling. These symptoms in elderly patients are suggestive of dry eye syndrome. Itching is also frequently associated with allergic disorders.
Acute hordeolum (stye) is a common infection of the glands of the eyelids. External hordeolum involve the glands of Zeis or Moll. Internal hordeolum is an infection of the meibomian glands. The usual causative agent is Staphylococcus aureus. Acute hordeolum is characterized by pain, localized swelling, and redness of the eyelid. A large hordeolum is infrequently associated with a preauricular lymph node.
If there is no abscess formation, treatment with warm compresses three times daily and topical broad-spectrum antibiotic drops such as tobramycin or sulfacetamide 10% three or four times daily for 5-7 days usually suffices. Ophthalmic ointments (erythromycin or bacitracin) twice daily for 5-7 days are also effective. Oral antibiotics, especially tetracycline derivatives, can be useful for patients with acne rosacea. If the infection does not resolve and is localized, treatment consists of making a local horizontal (skin) or vertical (conjunctiva) incision.
Herpes zoster virus (HZV) is caused by a reactivation of latent varicella virus (chickenpox) dormant in the dorsal root ganglion. Approximately 15% of herpes zoster cases arise from the ophthalmic division of the trigeminal nerve (herpes zoster ophthalmicus [HZO]). Hutchinson sign (involvement of the nasociliary nerve which supplies the tip of the nose) occurs in about one-third of patients with HZO. If present, it suggests intraocular involvement. Reactivation is associated with decreased cell-mediated immunity and patients with HIV, blood dyscrasias, neoplasms, or other forms of immunosuppression are at increased risk.
HZO can involve virtually any ocular and adnexal tissues. Reactivation often starts with headache, malaise, fever, and ocular pain without cutaneous findings. Within 24-48 hours, the classic vesicular lesions develop unilaterally in a dermatomal distribution. Corneal involvement presents with the acute event or may follow it by months or years. A corneal pseudodendritic pattern is common. Conjunctivitis, keratitis, episcleritis/scleritis, and uveitis can also occur. Dry eye and poor corneal sensation are common.
Treatments of skin lesions include warm compresses and topical antibiotic ointment. Aggressive lubrication is often needed for maintenance of the ocular surface. Oral antiviral medication is the standard of care. Oral acyclovir (800 mg five times a day) or valacyclovir (1000 mg three times a day) initiated within 72 hours of symptoms has been demonstrated to accelerate the resolution of skin rash and the healing of skin lesions, reduce lesion formation and viral shedding and reduce the incidence of episcleritis, keratitis, and iritis. Oral antivirals appear to reduce both acute zoster-associated pain and postherpetic neuralgia. Topical antiviral medication and steroids are used in certain situations to treat corneal lesions or uveitis. The Zostavax vaccine has been approved for the prevention of herpes zoster in the elderly. In patients without known risk factors for HZO (patients under age 50 without chronic immunosuppression) consider HIV testing.
Dacryocystitis is a common infection of the lacrimal sac. Acute or chronic, it occurs most often in infants and in persons older than 40 years. It is usually unilateral and always secondary to obstruction of the nasolacrimal duct. In rare instances, the nasolacrimal duct may be obstructed by a tumor.
In children the nasolacrimal duct opens spontaneously during the first month of life. Failure of canalization leads to obstruction of the sac and secondary dacryocystitis. The cause of acquired nasolacrimal duct obstruction is often unclear, but trauma to the nose or infection may be responsible. In infants, dacryocystitis leading to obstruction may be due to Haemophilus influenzae, staphylococci, or streptococci. In patients with trachoma, nasolacrimal and canalicular obstruction is common. The cause of acute dacryocystitis in adults is usually S. aureus or β-hemolytic streptococci. In chronic dacryocystitis, Streptococcus pneumoniae is a common pathogen.
Acute dacryocystitis is characterized by pain, swelling, tenderness, and redness in the tear sac area. In chronic dacryocystitis, tearing and discharge are the principal signs. Purulent material can often be expressed through the puncta.
Culture and sensitivity of organisms obtained from cotton swab should be performed.
Acute dacryocystitis responds well to systemic antibiotic therapy, but recurrences are common if the obstruction is not surgically relieved.
When ductal obstruction is due to failure of canaliculization in the first month of life, daily vigorous massage of the tear sac is indicated. Topical antibiotics should be instilled in the conjunctival sac four or five times daily. If this is not successful, probing of the nasolacrimal duct is indicated. Most ophthalmologists postpone probing until age 6-9 months to allow sufficient time for the passage to open on its own. Both the upper and the lower canaliculi should be probed. In cases of previous failure or in children older than age 2, balloon dacryocystoplasty at the time of probing may increase chances of success. In recalcitrant cases, stenting of the nasolacrimal system or surgical creation of a new tear drain between the eye and nose (dacryocystorhinostomy) is required.
Orbital cellulitis is characterized by an abrupt onset of swelling and redness of the lids, accompanied by proptosis, decreased vision, diplopia, and fever. It is usually caused by staphylococci or streptococci. Immediate treatment with intravenous antibiotics is indicated to prevent abscess formation and rapid increase in the orbital pressure with compromise of the blood supply to the eye. The response to antibiotics is usually excellent, but surgical drainage may be required if an abscess forms. Computerized tomography (CT) is indicated to rule out abscess formation. Preseptal cellulitis is limited to the area anterior to the orbital septum and is treated with oral antibiotics while monitoring closely for progression to full-blown orbital infection.
Acute conjunctivitis is a common cause of red eye. Infectious causes include bacterial, viral, chlamydial, fungal, and parasitic agents. Noninfectious causes include chemical irritation, allergy, hypersensitivity to topical medications, vitamin A deficiency, dry eye syndrome, floppy eyelid syndrome associated with obstructive sleep apnea and injury.
Patients with conjunctivitis complain of redness, irritation, foreign-body sensation, and conjunctival discharge. One or both eyes may be affected. The eyelids are often stuck together in the morning. Bacterial conjunctivitis has conjunctival hyperemia with purulent or mucopurulent discharge and variable degrees of lid swelling. Gonococcal conjunctivitis is characterized by hyperacute onset of copious mucopurulent discharge and can be a vision-threatening infection. In viral conjunctivitis, follicles are present in the inferior conjunctival fornix and preauricular lymph nodes are often involved. The hallmark symptom of allergic conjunctivitis is itching.
If bacterial conjunctivitis is suspected, appropriate microbiologic testing should be performed, including blood and chocolate agar plates, Gram and Giemsa stains, and bacterial cultures.
For patients with suspected bacterial conjunctivitis, topical broad-spectrum antibacterial agents should be prescribed (eg, sulfacetamide 10% eye drops or ciprofloxacin 0.3% eye drops QID), with the addition of erythromycin or bacitracin ophthalmic ointment at bedtime if clinical indications warrant.
Viral conjunctivitis is usually self-limited and does not require treatment. If the diagnosis is unclear, topical antibiotics are often used. Contact precautions are necessary in all situations of suspected bacterial and viral conjunctivitis because spread of disease occurs through contact with contaminated tears.
Treatment of patients with allergic conjunctivitis consists of topical decongestants (naphazoline 0.1%) and H1 receptor blocker (levocabastine) or a mast cell stabilizer (cromolyn). Combination mast cell and antihistamine drops such as olopatadine are also available. In severe cases of allergic conjunctivitis, topical corticosteroids or cyclosporine might be required but should be initiated only with the assistance of an ophthalmologist.
Corneal infections leading to ulceration may be due to bacteria, viruses, fungi, or protozoa.
Patients with corneal ulcers complain of pain, photophobia, and blurring of vision. Patients develop conjunctival hyperemia and chemosis with ulceration of the cornea and whitish or yellowish infiltrate. Hypopyon (pus in the anterior chamber) may be present in cases caused by bacterial or fungal infections. Contact lens users and people with diminished corneal sensation or incomplete eyelid closure are at increased risk of developing corneal infections.
Laboratory studies include culture and cytologic inspection of corneal scrapings.
Corneal ulceration is a serious condition requiring careful management to avoid permanent visual loss. The most devastating infection of the cornea is caused by Pseudomonas aeruginosa. Topical antibiotics should be given on an empirical basis until the results of culture and sensitivity tests are available. Organism-specific antimicrobial treatment should then be started. Patients using topical corticosteroids should stop using them. Central corneal ulcers may leave corneal scars, causing loss of vision. Patients severely affected may require corneal transplantation.
Patients wearing contact lenses (especially extended-wear contacts) are at higher risk of corneal ulcers. Contact lens wear should be stopped if corneal infection is suspected.
Herpes simplex virus (HSV) is a DNA virus that can affect the eye either in a primary ocular reaction or a reactivated state when latent virus travels down the axon of the sensory nerve to its target tissue. HSV is extremely common, with about 90% of the population seropositive for HSV antibodies. HSV-1 usually causes infection above the waist (face, lips, and eyes); HSV-2 infections are usually below. Rarely, HSV-2 is transmitted during birth to the infant eye through infected genital secretions (Table 37-2).
| HSV | HZV | |
|---|---|---|
| Rash | Clear vesicles on erythematous base; crusting | Vesicular rash along dermatomal distribution, not crossing midline; Hutchinson sign (nasociliary branch of V1) may be present |
| Epithelial lesion | Dendritic epithelial lesions with heaped edges | Pseudodendrites (mucous plaques without true terminal bulbs) |
| Staining | Edges stain with rose bengal; central ulceration stains with fluorescein | Minimal fluorescein staining |
| Patient population | Young | Older or immunocompromised |
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