Ординатура / Офтальмология / Английские материалы / Primary Care Ophthalmology_Palay, Krachmer_2005

324 CHAPTER 15 • Systemic Disease and Therapies

FIGURE 15–29 Advanced pigmentary changes in the macula and retinal periphery resulting from thioridazine (Mellaril) toxicity.

Treatment

•Pigment deposition in the cornea and lens is not visually significant and does not require a change in treatment.

•Thioridazine (Mellaril) is discontinued if signs or symptoms of retinal toxicity occur. Early retinal changes may be reversible.

Follow-up

• An annual ophthalmologic follow-up (every 6 months with Mellaril) is suggested.

Plaquenil Use

Hydroxychloroquine (Plaquenil) is used in the treatment of collagen-vascular disease. A host of ocular side effects have been reported with this drug, but in general, the incidence of ocular toxicity with Plaquenil is less than that with chloroquine. Most of the observable effects are in the cornea, which usually are reversible, and the retina, which may be reversible or permanent.

Symptoms

•No symptoms related to ocular discomfort are associated with Plaquenil use.

•Vision is blurred.

•Focusing is difficult.

•Night blindness occurs.

•Blind spots (scotomata) are present in the visual field.

Signs

•Punctate to linear, whorl-shaped lesions in the corneal epithelium may be seen on slit lamp examination. These deposits may be seen early after the patient begins medication but usually are not visually significant.

FIGURE 15–30 Plaquenil toxicity. Although rarely seen, retinal 1 toxicity may occur with Plaquenil (hydroxychloroquine) use.

In this case, a classic bull’s-eye pattern of macular change (1) is evident. The daily dose used was greater than 7 mg/kg of lean body weight.

•The retina may show mild pigment stippling of the macula (Fig. 15–30) and a decrease or loss of the normal foveal reflex. If the effects are progressive, a bull’s- eye pattern of maculopathy occurs in which pigment clumps are present centrally, surrounded by a ring of relative hypopigmentation encircled by a zone of relative hyperpigmentation. In extreme cases, optic atrophy, pallor of the disc with narrowing of the retinal arterioles, and pigmentary changes in the retinal periphery may be seen.

Workup

•A baseline ophthalmologic examination, including visual acuity assessment, color vision testing, slit lamp examination, dilated funduscopic examination, and examination of the central visual field, is indicated.

Treatment

•Ocular changes are virtually never seen with antimalarial prophylaxis but occur when the drug is used daily for treatment of systemic lupus erythematosus or rheumatoid arthritis. Recent evidence suggests that the rate of dosage is important; with a daily Plaquenil dose of 6.5 mg/kg (of ideal body weight) or less, retinopathy is virtually never seen.

•With early documented pigment changes on the retina or visual field changes, discontinuation of the drug may reverse any initial visual acuity or visual field effects. Rarely, visual field effects may progress after medication is discontinued. The frequency of retinal toxicity may increase in older age groups (60 years of age or older), but age-related macular degeneration changes also are more likely with increasing age.

•All patients should be advised to wear sunglasses (for ultraviolet light [UV] protection) and a hat with a brim in sunny climates, because light may play a role.

•Immediate evaluation of any patient with symptoms is indicated.

326 CHAPTER 15 • Systemic Disease and Therapies

Follow-up

•The frequency of follow-up evaluations in patients taking Plaquenil is controversial. The manufacturer still recommends every 3 months. Many ophthalmologists, however, believe that the incidence of retinal findings is so rare with Plaquenil that every 6 months or even annual follow-ups are sufficient. Because the retinal changes may be reversible if found early and irreversible if found too late, a follow-up every 6 months appears reasonable in the usual patient who is symptom free.

•Thus, a recommended schedule for ophthalmic follow-up evaluation in a patient without symptoms who is taking Plaquenil is as follows:

With low dosage (e.g., 200 mg per day): once a year

With usual dosage (approaching but not exceeding 6.5 mg/kg [ideal body weight] per day): every 6 months

With higher dosages (greater than 6.5 mg/kg per day): every 3 to 4 months in most cases

With decreased renal function: downward adjustment of the dosage and evaluation of ocular status every 3 to 4 months

With history of or concomitant gold or phenothiazine therapy: adjustment of the dosage and monitoring of the ophthalmic status every 3 to 4 months, because the threshold for retinal toxicity may be lower

Tamoxifen Use

Tamoxifen is a nonsteroidal antiestrogen that may have asymptomatic or symptomatic ocular effects.

Symptoms

•No symptoms related to ocular discomfort occur.

•Vision is blurred or decreased.

Signs

•White subepithelial opacities are present in the cornea.

•Crystalline deposits are found in the retina, located in the paramacular area (Fig. 15–31).

•In rare cases, cystoid macular edema occurs.

•Optic neuritis, which may be dose related or idiosyncratic, may occur.

Treatment

•No treatment is indicated unless visual acuity changes are documented, in which case the drug is discontinued.

•Cornea lesions are reversible, but visual loss secondary to retinopathy may be permanent.

•Screening for retinopathy or optic neuropathy is not warranted, but any vision change should be evaluated by an ophthalmologist.

328 CHAPTER 15 • Systemic Disease and Therapies

nosum. A closely related isozyme, phosphodiesterase 6 (PDE6), is present in high concentrations in the cone and rod cells of the retina.

Symptoms

•Transient impairment of blue-green discrimination may occur.

•Blue-color tinge to vision may be described by the patient.

•Sensitivity to light may be increased.

Signs

• No ocular signs are present.

Treatment

•No treatment is required, because all eye symptoms are transient.

•No evidence of ocular toxicity has been documented, nor have any effects on visual acuity or visual field.

•Because PDE5 does cross-react with PDE6, the theoretical risk of serious ocular side effects is increased in patients with retinitis pigmentosa, or other severe retinal diseases.

330 CHAPTER 16 • Ocular Trauma

FIGURE 16–1 Periorbital contusion.

1

2

FIGURE 16–2 Orbital computed tomography scan showing sequelae of blunt orbital or ocular injury. The patient was struck with a can of soda, causing a dislocated lens (1), retrobulbar hemorrhage (2), and blow-out fracture of the medial orbital wall.

Workup

•A general examination is performed on both eyes; dilated examination is mandatory. The red reflex is examined through the dilated pupil to evaluate lens position and clarity.

•Plain x-ray films and/or computed tomography (CT) study of the orbit is needed if orbital fracture is suspected. Entrapment of orbital soft tissue in an orbital blow-out fracture often is seen clearly on CT scans.

Treatment

•If no severe ocular or periocular injury is evident, cool compresses are applied, and the patient is reassured. To avoid sports-related injury in a child, use of safety glasses or goggles should be encouraged.

•Nonemergency ophthalmologic follow-up is needed—specifically, a careful peripheral retinal examination. Trauma severe enough to cause substantial periorbital edema and ecchymosis can cause a tear in the retinal periphery that may not cause symptoms initially but may result in a delayed retinal detachment if not identified.

•Patients with evidence of hyphema should be immediately referred to an ophthalmologist.

Corneal Abrasion

Symptoms

•A history of mild trauma to the eye, possibly caused by a fingernail, tree branch, contact lens, make-up brush, or foreign body, is reported.

•Photophobia, conjunctival injection, and involuntary lid closure (blepharospasm) are characteristic.

•Pain and foreign body sensation may be quite severe.

•If the abrasion is in the central cornea, visual acuity is decreased (20/80 to 20/200).

Signs

•Conjunctival hyperemia, swollen eyelids, and tearing are noted.

•Slit lamp examination shows an epithelial defect but often an otherwise clear cornea. A surface irregularity may be identified with a penlight. Minimal cellular reaction is seen in the anterior chamber. If corneal haze or moderate to severe “flare and cell” is noted in the anterior segment, especially with an associated discharge, bacterial superinfection may be present.

•Fluorescein dye is absorbed by areas devoid of epithelium and outlines the defect (Fig. 16–3).

•Immediate relief is obtained with topical anesthesia (e.g., proparacaine, tetracaine). Topical anesthetics are used only to confirm the diagnosis and are not prescribed for long-term relief.

Differential Diagnosis

•Diagnostic considerations include the following:

Viral keratitis (herpes simplex or zoster), often with corneal dendrites (see Fig. 6–7)

Corneal or conjunctival foreign body, especially trapped on the conjunctiva under the upper lid, which can cause “ice-skate track” abrasions as the foreign body is repeatedly swept linearly over the corneal epithelium

Recurrent erosion, which is similar to a primary epithelial defect (abrasion) but occurs long after the initial corneal trauma, due to re-epithelialization healing problems (see Fig. 6–18)

Ultraviolet corneal injury (welder’s flash, tanning booth exposure) (see Fig. 16–3)

Workup

•The area of denuded epithelium is documented. Location is important because any complications (infections) in the central portion of the cornea may have lasting visual consequences.

•The eyelids are everted to search for a foreign body, especially if the history is suggestive (e.g., glass from an automobile accident, vegetable matter from bark). Linear corneal abrasions should alert the examiner to flip the upper lid to look for the foreign body on the superior tarsal conjunctiva.

332 CHAPTER 16 • Ocular Trauma

B

A

Treatment

•For contact lens–associated corneal abrasions, see page 334.

•For non–contact lens–associated abrasions, the following apply:

A cycloplegic agent (e.g., homatropine 5% two to three times a day) is administered.

Antibiotic ointment appropriate for the injury is used. Polymyxin B/bacitracin (Polysporin) or erythromycin ophthalmic ointment twice a day and at bedtime is effective for most abrasions.

If the abrasion is large (more than 5 to 10 mm across) or the patient is in severe pain, cycloplegic drops and antibiotic ointment are instilled, followed by firm application of a pressure patch for 24 hours. (See Chapter 1 for proper patch application.) Although pressure patching promotes wound healing, the chance of infection is increased when a warm environment is created by the patching. In circumstances in which microbial contamination exists (especially in the setting of contact lens wear), use of a pressure patch is avoided.

Analgesia is given for pain; sometimes a narcotic analgesic is needed (e.g., acetaminophen plus codeine [Tylenol with Codeine]).

Under no circumstances should topical anesthetics be prescribed or given to the patient. Not only do anesthetics retard wound reepithelialization, but the loss of the cornea’s normal pain response predisposes the patient to a much more severe injury.

Patients with a large central abrasion or high-risk abrasion should be referred to an ophthalmologist for management and follow-up care.

Follow-up

•All abrasions are monitored every day or two until they have completely resolved. If healing takes longer than 2 or 3 days, the patient should be referred to an ophthalmologist.

•Use of a pressure patch for more than 24 hours should be avoided. If patient compliance with follow-up is questionable, antibiotic ointment and cycloplegic drops are indicated to heal the abrasion without the added risk of patching.

•If visual acuity is markedly decreased (less than 20/400), more severe ocular injury needs to be ruled out, especially if the history suggests severe trauma.

Contact Lens Injury

Symptoms

•Pain, foreign body sensation, photophobia, tearing, and blepharospasm are noted immediately after insertion or removal of a contact lens.

•Blurred vision, conjunctival hyperemia, and pain during contact lens wear are characteristic. The presence of these symptoms on awakening suggests hypoxic corneal injury.

Signs

•Conjunctival hyperemia and ciliary flush, which is a manifestation of circumlimbal injection (redness around the corneoscleral junction), are noted.

•An epithelial defect is present if an abrasion exists.

•The contact lens is immobile and corneal edema is diffuse (in cases of tight lens syndrome or hypoxic corneal injury).

Etiology

•Direct trauma to the corneal epithelium with insertion or removal of the lens can result in injury.

•A foreign body between the lens and cornea can cause injury (Fig. 16–4).

•Hypoxic injury to the cornea results from improper contact lens fit, improper lens material for the patient’s needs, or overwear by the patient (e.g., sleeping in a daily wear lens). While the patient sleeps, the oxygen available to the cornea is markedly decreased, and with a lens that is poorly oxygen-permeable, the corneal epithelium becomes hypoxic and edematous.

•Toxic product buildup in the contact lens can result in injury.