6.1 Eye & Vision Disorders in Adult-Gerontology Primary Care

Eye & Vision Disorders in Adult-Gerontology Primary Care

The ANCC test content outline names head, eyes, ears, nose and throat as one of thirteen body systems used to build examination items, and eye, ear, nose and skin as one of twelve drug-agent classes. Eye complaints are also among the highest-stakes presentations in primary care: a handful of conditions can destroy vision within hours, and several of them mimic the benign ones.

The single organizing question for any acute eye complaint is: is vision or the globe threatened?

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1. The Red Eye: The Danger Triad

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|                          RED EYE: THE THREE RED-FLAG FINDINGS                                     |
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|   ANY of the following converts a "red eye" into an OPHTHALMOLOGIC EMERGENCY:                     |
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|   1. VISION LOSS ......... Reduced visual acuity that does not clear with blinking                 |
|   2. TRUE PAIN ........... Deep, aching, boring ocular pain (NOT itching, grittiness or burning)   |
|   3. PHOTOPHOBIA ......... Especially consensual photophobia, plus ciliary flush (limbal injection)|
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|   Supporting red flags: pupil abnormality (fixed, mid-dilated, irregular or poorly reactive),      |
|   corneal opacity or haze, hypopyon, contact lens wear, recent ocular trauma or surgery,           |
|   immunosuppression, or a vesicular rash in the V1 dermatome.                                      |
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Acute angle-closure glaucoma is the classic board vignette: an older, often hyperopic patient develops severe unilateral eye pain, headache, nausea and vomiting, and sees halos around lights after entering a dark room or after taking a medication with anticholinergic or sympathomimetic activity. The globe feels rock-hard on gentle palpation through the closed lid and the intraocular pressure is typically above 40 mmHg. This is an emergency: refer immediately, keep the patient in a lit room, and do not dilate the pupil.

[!WARNING] Three prescribing traps in the red eye.

1. Never prescribe a topical corticosteroid for an undifferentiated red eye. If the cause is herpes simplex dendritic keratitis or a fungal keratitis, a steroid accelerates stromal melt and corneal perforation.
2. Never patch the eye of a contact lens wearer. A closed, warm, moist environment is ideal for Pseudomonas aeruginosa, which can perforate a cornea in 24 to 48 hours.
3. Never dispense topical anesthetic for home use. Repeated proparacaine or tetracaine is epithelially toxic and abolishes the protective blink, producing neurotrophic ulceration.

Managing uncomplicated conjunctivitis. Bacterial conjunctivitis in adults is usually self-limited; when treatment is chosen, use a topical antibiotic such as erythromycin ointment, polymyxin-trimethoprim, or a fluoroquinolone for contact lens wearers (who need Pseudomonas coverage). Adenoviral conjunctivitis - watery discharge, preauricular lymphadenopathy, often a recent upper respiratory infection - is highly contagious for 10 to 14 days and needs hygiene counseling and cool compresses, not antibiotics. Allergic conjunctivitis is bilateral and itchy; treat with an ocular antihistamine/mast-cell stabilizer such as olopatadine.

Herpes zoster ophthalmicus. A vesicular rash in the V1 distribution with lesions on the tip of the nose (Hutchinson sign, nasociliary nerve involvement) predicts ocular involvement. Start oral antiviral therapy within 72 hours and obtain same-day ophthalmology evaluation.

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2. Sudden Painless Vision Loss: Four Diagnoses to Separate

Vitreous floaters without a curtain are usually a benign posterior vitreous detachment, but a sudden increase in floaters or new flashes requires dilated examination within 24 to 48 hours to exclude a retinal tear.

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3. Chronic Age-Related Eye Disease

Cataract. A painless, gradual, bilateral (often asymmetric) decline in vision with glare and halos around headlights at night, difficulty reading in low light, and a diminished red reflex. Second sight - transient improvement in near vision from a myopic shift in nuclear sclerosis - is a classic clue. Risk factors include age, ultraviolet exposure, smoking, diabetes and chronic systemic or inhaled corticosteroid use (posterior subcapsular cataract). Refer for surgery when vision limits the activities the patient values, especially driving.

Primary open-angle glaucoma. Painless and asymptomatic until late, which is why patients present having already lost peripheral field. Findings are an increased cup-to-disc ratio (greater than 0.5, or asymmetry greater than 0.2 between eyes), disc rim notching, and arcuate visual field defects. Risk factors: age, African ancestry, family history, diabetes, myopia, and elevated intraocular pressure. First-line pharmacotherapy is a topical prostaglandin analog such as latanoprost once nightly (side effects: iris and periocular hyperpigmentation, eyelash growth). Topical beta-blockers such as timolol are absorbed systemically and can cause bronchospasm, bradycardia and heart block - screen for asthma, COPD and conduction disease before they are prescribed, and teach punctal occlusion.

Age-related macular degeneration. Central vision loss with preserved peripheral vision.

• Dry (non-neovascular), about 85 to 90 percent: drusen and retinal pigment epithelial changes, gradual central blurring.
• Wet (neovascular), about 10 to 15 percent: rapid distortion - straight lines appear bent (metamorphopsia) - and central scotoma from choroidal neovascularization. Requires urgent referral for anti-VEGF intravitreal injection.
• Home monitoring with an Amsler grid; any new distortion prompts urgent evaluation.
• AREDS2 supplementation slows progression in intermediate or advanced disease: vitamin C 500 mg, vitamin E 400 IU, lutein 10 mg, zeaxanthin 2 mg, zinc 80 mg (25 mg is an accepted alternative) and cupric oxide 2 mg. AREDS2 removed beta-carotene because it increased lung cancer incidence in current and former smokers. AREDS2 does not prevent macular degeneration in people who do not already have it.

Diabetic retinopathy. The leading cause of new blindness in working-age US adults. Non-proliferative disease shows microaneurysms, dot-blot hemorrhages, hard exudates and cotton-wool spots; proliferative disease adds neovascularization with the risk of vitreous hemorrhage and tractional detachment. Diabetic macular edema can occur at any stage and is the most common cause of vision loss in diabetes. Per the ADA Standards of Care, arrange a dilated comprehensive eye examination at the time of type 2 diabetes diagnosis and within 5 years of type 1 diabetes onset, then at least annually; the interval may be extended to every 1 to 2 years when there is no retinopathy and glycemia is well controlled. Pregnancy accelerates retinopathy and requires examination in the first trimester and close follow-up.

Presbyopia - the progressive loss of accommodation from lens stiffening beginning in the fifth decade - is universal, benign and corrected with reading addition.

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4. Screening Recommendations

The USPSTF concludes that current evidence is insufficient (Grade I) to assess the balance of benefits and harms of screening for impaired visual acuity in asymptomatic older adults and of screening for primary open-angle glaucoma in asymptomatic adults. This is a favorite distractor: the absence of a USPSTF recommendation is not evidence that eye examinations are useless. Disease-specific surveillance driven by diabetes, glaucoma risk factors or symptoms is standard of care regardless, and professional ophthalmology organizations recommend periodic comprehensive eye examinations in older adults.