Corrective Glasses.

Myopia, hyperopia, presbyopia, and astigmatism can be modified by using the appropriate corrective lenses. Glasses for presbyopia are often called “reading glasses” because they are usually worn for close work only. The presbyopic correction may also be combined with a correction for another refractive error, such as myopia or astigmatism. In these combined glasses the presbyopic correction is in the lower portion of the spectacle lens. A traditional bifocal or trifocal has visible lines. However, most lenses today that correct vision at various distances do not have visible lines. The prescription varies throughout the lens, allowing distance focusing in the top two thirds and near focus in the bottom one third of the lens.

Contact Lenses.

Contact lenses are another way to correct refractive errors. Contact lenses are made from various plastic and silicone substances that are highly permeable to oxygen and have a high water content. These features allow for increased wearing time with greater comfort. If the oxygen supply to the cornea is decreased, it becomes swollen, visual acuity decreases, and the patient experiences severe discomfort.

Altered or decreased tear formation can make wearing contact lenses difficult. Tear production can be decreased by medications such as antihistamines, decongestants, diuretics, and birth control pills, as well as the hormones produced during pregnancy. Environmental factors such as wind, fans, and dust may also decrease the tear film. Allergic conjunctivitis with itching, tearing, and redness can also affect contact lens wear.

In general, you need to know whether the patient wears contact lenses, the pattern of wear (daily versus extended), and care practices. Shining a light obliquely on the eyeball can help visualize a contact lens. Contact lenses are associated with microbial keratitis, a severe sight-threatening complication. Risk factors for keratitis include poor hand cleaning, poor lens case hygiene, and inadequate lens cleaning.² Teach the patient the importance of following recommended cleaning practices and reporting redness, sensitivity, vision problems, and pain to the eye care professional. Instruct the patient to remove contact lenses immediately if any of these problems occur.

Laser.

Laser-assisted in situ keratomileusis (LASIK) may be considered for patients with low to moderately high amounts of myopia or hyperopia, with or without astigmatism. The procedure first involves using a laser or surgical blade to create a flap in the cornea. The flap is folded back on the middle section, or stroma, of the cornea.³ Pulses from a computer-controlled laser vaporize a part of the stroma. The flap is then repositioned, adhering on its own without sutures in a few minutes.

Photorefractive keratectomy (PRK) is indicated for low to moderate amounts of myopia or hyperopia, with or without astigmatism and is a good option for a patient with insufficient corneal thickness for a LASIK flap. In PRK only the epithelium is removed, and the laser sculpts the cornea to correct the refractive error. Laser-assisted subepithelial keratomileusis (LASEK) is similar to PRK except that the epithelium is replaced after surgery.

Implant.

Refractive intraocular lens (refractive IOL) implantation is an option for patients with a high degree of myopia or hyperopia. Like cataract surgery, it involves removal of the patient’s natural lens and implantation of an IOL, which is a small plastic lens to correct a patient’s refractive error. Since this requires entering the eye, the risk of complications is higher. New accommodating IOLs correct both myopia and presbyopia.

Phakic intraocular lenses (phakic IOLs) are sometimes referred to as implantable contact lenses. They are implanted into the eye without removing the eye’s natural lens. They are used for patients with high degrees of myopia or hyperopia. Unlike refractive IOLs, the phakic IOL is placed in front of the eye’s natural lens. Leaving the natural lens in the eye preserves the eye’s ability to focus for reading vision. Artisan is one type of phakic IOL used for moderate to severe myopia.

Acute Intervention.

Provide emotional support and direct care to the patient with recent visual impairment. Allow the patient to express anger and grief, and help the patient identify fears and successful coping strategies. The family is intimately involved in the experiences that follow vision loss. With the patient’s knowledge and permission, include family members in discussions and encourage them to express their concerns.

Many people are uncomfortable around a blind or partially sighted individual because they are not sure what behaviors are appropriate. Being sensitive to the patient’s feelings without being overly worried or smothering the patient’s independence is vital in creating a therapeutic nursing presence. Always communicate in a normal conversational tone and manner with the patient, and address the patient, not the caregiver. Common courtesy dictates introducing oneself and any other people who approach the blind or partially sighted patient and saying good-bye on leaving. Making eye contact with the partially sighted patient accomplishes several objectives. It ensures that you are speaking while facing the patient so the patient has no difficulty hearing. Your head position validates that you are attentive to the patient. In addition, establishing eye contact ensures that you can observe the patient’s facial expressions and reactions.

Assist the patient using a sighted-guide technique. Stand slightly in front and to one side of the patient, and offer an elbow for the patient to hold. Serve as the sighted guide, walking slightly ahead of the patient with the patient holding the back of your arm. As you walk, describe the environment to help orient the patient. For example, “We’re going through an open doorway and approaching two steps down.” Help the patient sit by placing one of his or her hands on the seat of the chair.

Ambulatory and Home Care.

In working with the visually impaired patient, remember that a person classified as legally blind may have some useful vision. Rehabilitation after partial or total loss of vision can foster independence, self-esteem, and productivity. Know what services and devices are available for the partially sighted or blind patient, and make appropriate referrals. For the legally blind patient the primary resource for services is the state agency for rehabilitation of the blind. Legally blind individuals are eligible for federal and state assistance and income tax benefits. A list of agencies that serve the partially sighted or blind patient is available from the American Foundation for the Blind (www.afb.org). Many of these agencies are listed in the resources section at the end of the chapter.

Braille or audio books for reading and a cane or guide dog for ambulation are examples of vision substitution techniques. These are usually most appropriate for the patient with no functional vision. For most patients who have some remaining vision, vision enhancement techniques can provide help in learning to ambulate, read printed material, and accomplish activities of daily living (ADLs).

Bacterial Infections.

Acute bacterial conjunctivitis (pinkeye) is a common infection. Although it occurs in every age-group, epidemics are common among children because of their poor hygienic habits. S. aureus is the most common cause. The patient with bacterial conjunctivitis may complain of discomfort, pruritus, redness, and a mucopurulent drainage.⁹ Although this typically occurs initially in one eye, it generally spreads to the unaffected eye. It is usually self-limiting, but treatment with antibiotic drops (e.g., besifloxacin [Besivance]) shortens the course of the disorder.

Viral Infections.

Conjunctival infections may be caused by many different viruses. The patient with viral conjunctivitis may complain of tearing, foreign body sensation, redness, and mild photophobia. This condition is usually mild and self-limiting. However, it can be severe, with increased discomfort and subconjunctival hemorrhaging. Adenovirus conjunctivitis may be contracted in contaminated swimming pools and through direct contact with an infected patient. Treatment is usually palliative. If the patient is severely symptomatic, topical corticosteroids can provide temporary relief but have no effect on the final outcome. Antiviral drops are ineffective and therefore not indicated.

Chlamydial Infections.

Trachoma is a chronic conjunctivitis caused by Chlamydia trachomatis (serotypes A through C). It is a major cause of blindness worldwide. An estimated 84 million people have active disease in need of treatment if blindness is to be prevented, with 8 million people already living with irreversible vision loss.¹⁰

This preventable eye disease is transmitted mainly by the hands and by flies. Adult inclusion conjunctivitis (AIC) is caused by C. trachomatis (serotypes D through K). AIC is becoming more prevalent in the United States because of the increase in sexually transmitted chlamydial infection.

Manifestations of both trachoma and AIC are mucopurulent ocular discharge, irritation, redness, and lid swelling. For unknown reasons, AIC does not carry the long-term consequences of trachoma. AIC also differs from trachoma in that it is common in economically developed countries, whereas trachoma is most commonly seen in underdeveloped countries. Antibiotic therapy is usually effective for trachoma and AIC.

Although antibiotic treatment may be successful, patients with AIC have a high risk of concurrent chlamydial genital infection, as well as other sexually transmitted infections. In your teaching plan for these patients, include the sexual implications of AIC.

Allergic Conjunctivitis.

Conjunctivitis caused by exposure to an allergen can be mild and transitory, or it can be severe enough to cause significant swelling, sometimes ballooning the conjunctiva beyond the eyelids. The defining symptom of allergic conjunctivitis is itching. The patient may also complain of burning, redness, and tearing. In addition to pollens, the patient may develop allergic conjunctivitis in response to animal dander, ocular solutions, and medications. Instruct the patient to avoid the allergen if it is known. Artificial tears can be effective in diluting the allergen and washing it from the eye. Effective topical medications include antihistamines and corticosteroids.

Bacterial Infections.

The cornea can become infected by a variety of bacteria. Topical antibiotics are generally effective, but eradicating the infection may require subconjunctival antibiotic injection or, in severe cases, IV antibiotics. Risk factors include mechanical or chemical corneal epithelial damage, contact lens wear, nutritional deficiencies, immunosuppressed states, and contaminated products (e.g., lens care solutions and cases, topical medications, cosmetics).

Viral Infections.

Herpes simplex virus (HSV) keratitis is the most frequently occurring infectious cause of corneal blindness in the Western hemisphere. It is a growing problem, especially with immunosuppressed patients. The corneal ulcer has a characteristic dendritic (tree-branching) appearance. Pain and photophobia are common. Up to 40% of patients with herpetic keratitis heal spontaneously.

Antiviral treatments include trifluridine drops (Viroptic), oral acyclovir (Zovirax), and topical vidarabine (Vira-A) ointment.¹¹ Therapy may also involve corneal debridement. Topical corticosteroids are usually contraindicated because they contribute to a longer course and possible deeper ulceration of the cornea.

The varicella-zoster virus (VZV) causes both chickenpox and herpes zoster ophthalmicus (HZO). HZO may occur by reactivation of an endogenous infection that has persisted in a latent form after an earlier attack of varicella or by contact with a patient with chickenpox or herpes zoster. It occurs most frequently in the older adult and in the immunosuppressed patient. Collaborative care of the patient with acute HZO may include analgesics for the pain, topical corticosteroids to reduce inflammation, antiviral agents such as acyclovir to reduce viral replication, mydriatic agents to dilate the pupil and relieve pain, and topical antibiotics to combat secondary infection. The patient may apply warm compresses and povidone-iodine gel to the affected skin (gel should not be applied near the eye).

Epidemic keratoconjunctivitis (EKC) is the most serious ocular adenoviral disease. EKC is spread by direct contact, including sexual activity. In the medical setting, contaminated hands and instruments can be the source of spread. The patient may complain of tearing, redness, photophobia, and foreign body sensation. In most patients the disease involves only one eye. Treatment is primarily palliative and includes ice packs and dark glasses. In severe cases therapy can include mild topical corticosteroids to temporarily relieve symptoms and topical antibiotic ointment. Teach the patient and the caregiver the importance of good hygiene practices to avoid spreading the disease.

Other Causes of Keratitis.

Keratitis may also be caused by fungi (most commonly Aspergillus, Candida, and Fusarium species), especially in the case of ocular trauma in an outdoor setting where fungi are prevalent in the soil and moist organic matter.

Acanthamoeba keratitis is caused by a parasite that is associated with contact lens wear, probably as a result of contaminated lens care solutions or cases. Homemade saline solution is particularly susceptible to Acanthamoeba contamination. Instruct the patient who wears contact lenses about good lens care practices. Medical treatment of Acanthamoeba keratitis is difficult, since the organism is resistant to most drugs. Only one antifungal eyedrop (natamycin [Natacyn]) is approved by the U.S. Food and Drug Administration (FDA). If antimicrobial therapy fails, the patient may require a corneal transplant.

Exposure keratitis occurs when the patient cannot adequately close the eyelids. The patient with exophthalmos (protruding eyeball) from thyroid eye disease or masses posterior to the globe is susceptible to exposure keratitis.

Corneal Ulcer.

Tissue loss caused by infection of the cornea produces a corneal ulcer (infectious keratitis) (Fig. 22-2). The infection can be due to bacteria, viruses, or fungi. Corneal ulcers are often painful, and patients may feel as if there is a foreign body in their eye. Other symptoms can include tearing, purulent or watery discharge, redness, and photophobia. Treatment is generally aggressive to avoid permanent loss of vision. Antibiotic, antiviral, or antifungal eyedrops may be prescribed as frequently as every hour night and day for the first 24 hours. An untreated corneal ulcer can result in corneal scarring and perforation (hole in the cornea). A corneal transplant may be indicated.

Keratoconus

Keratoconus is a noninflammatory, usually bilateral disease that has a familial tendency. Keratoconus usually appears during adolescence and slowly progresses between ages 20 and 60 years. The anterior cornea thins and protrudes forward, taking on a cone shape. The only symptom is blurred vision. The astigmatism may be corrected with glasses or rigid contact lenses.

Intacs inserts are two clear plastic lenses surgically inserted on the cornea perimeter to reduce astigmatism and myopia. Intacs are generally used to delay the need for a corneal transplant when contact lenses or glasses no longer help a patient achieve adequate vision.

The cornea can perforate as central corneal thinning progresses. In advanced cases a penetrating keratoplasty is indicated before perforation.