Section 10.1: Ophthalmic Disorders (Glaucoma, Conjunctivitis, Cataracts)
Key Takeaways
- Acute angle-closure glaucoma is a sight-threatening emergency presenting with sudden unilateral pain, a mid-dilated fixed pupil, and a steamy cornea; manage immediately with timolol, apraclonidine, pilocarpine, and systemic acetazolamide.
- Gonioscopy is the gold standard for diagnosing angle-closure glaucoma, while tonometry measures the intraocular pressure (typically 40-70 mmHg during an acute attack).
- Bacterial conjunctivitis in contact lens wearers requires topical fluoroquinolones (e.g., ciprofloxacin) to cover for Pseudomonas aeruginosa.
- Cataracts present with progressive, painless, bilateral vision loss and glare (especially at night); examination reveals a cloudy lens and a diminished red reflex, managed definitively with surgical extraction.
Section 10.1: Ophthalmic Disorders (Glaucoma, Conjunctivitis, Cataracts)
Why This Topic Matters for PANCE
Ophthalmic disorders are highly tested on the PANCE. Focus on differentiating benign inflammatory processes like conjunctivitis from vision-threatening emergencies like acute angle-closure glaucoma. Clinicians must identify pathognomonic exam findings (e.g., a steamy cornea or mid-dilated fixed pupil), select correct diagnostic tools (e.g., tonometry, slit-lamp), and initiate prompt, guideline-directed therapy.
Acute Angle-Closure Glaucoma (AACG)
Pathophysiology & Risk Factors
Acute angle-closure glaucoma (AACG) is an ophthalmic emergency characterized by a rapid, severe increase in intraocular pressure (IOP). Normally, aqueous humor is produced by the ciliary body in the posterior chamber, flows through the pupil, and drains via the trabecular meshwork into the Canal of Schlemm. In patients with predisposing anatomy (e.g., shallow anterior chambers, hyperopia), the peripheral iris contacts the trabecular meshwork, closing the drainage angle.
This blockade prevents aqueous humor exit, causing a sudden spike in IOP. Precipitants include pupillary dilation (mydriasis), which bunches the peripheral iris into the angle. Triggers include dark environments (e.g., movie theaters), stress, or mydriatic medications (e.g., sympathomimetics, antihistamines, decongestants).
Clinical Presentation & Physical Exam
Patients present with the sudden onset of severe, unilateral eye pain, headache, and blurred vision with colored halos around lights. Systemic symptoms like nausea, vomiting, and abdominal pain are common due to vagal stimulation. Key physical findings include:
- Ciliary flush: Diffuse conjunctival injection surrounding the limbus.
- Steamy cornea: Corneal edema from high pressure.
- Mid-dilated, fixed, nonreactive pupil: Caused by iris sphincter ischemia.
- Firm, hard globe: Apparent on digital palpation.
Diagnostic Workup
The initial diagnostic test of choice is tonometry to measure IOP. Normal IOP is 10 to 21 mmHg; in AACG, it is markedly elevated (typically 40 to 70 mmHg). The gold standard for visualizing a closed anterior chamber angle is gonioscopy, performed by an ophthalmologist, though it should not delay treatment.
Clinical Management
- First-line Medical Therapy:
- Topical Timolol 0.5% (Beta-Blocker): Reduces aqueous production. (Contraindicated in bradycardia, advanced heart block, asthma, or COPD).
- Topical Apraclonidine 1% (Alpha-2 Agonist): Decreases aqueous production and increases outflow.
- Topical Pilocarpine 2% (Miotic): Pulls the iris away from the trabecular meshwork. Effective only once IOP drops below 40 mmHg.
- Systemic Acetazolamide (500 mg IV/PO): Rapidly decreases aqueous production.
- Systemic Osmotic Agents (IV Mannitol): Used if IOP remains refractory.
- Definitive Management: Bilateral Laser Peripheral Iridotomy (LPI). Creates an iris opening to restore aqueous flow. Both eyes are treated because the contralateral eye is anatomically predisposed.
Conjunctivitis
Conjunctivitis is inflammation of the conjunctiva. It is classified into bacterial, viral, or allergic forms.
Bacterial Conjunctivitis
- Pathogens: S. aureus (adults), S. pneumoniae, H. influenzae (children).
- Presentation: Redness, foreign body sensation, and thick, purulent discharge. Eyelids are classically glued shut in the morning.
- Management:
- Non-Contact Lens Wearers: First-line is Erythromycin 0.5% ointment or Polytrim drops.
- Contact Lens Wearers: Carry a high risk of Pseudomonas aeruginosa. First-line is a topical fluoroquinolone (e.g., Ciprofloxacin 0.3% or Ofloxacin 0.3% drops). Suspend contact lens use.
- Hyperacute Gonococcal Conjunctivitis: Caused by N. gonorrhoeae. Copious purulent discharge. Requires urgent ophtho referral, saline flushes, and Ceftriaxone 1g IM to prevent corneal perforation.
Viral Conjunctivitis
- Pathogen: Most commonly Adenovirus (highly contagious).
- Presentation: Watery discharge, grittiness, palpebral follicles, and ipsilateral preauricular lymphadenopathy. Spreads from one eye to the other within 24-48 hours.
- Management: Supportive (cool compresses, artificial tears).
Allergic Conjunctivitis
- Pathophysiology: IgE-mediated hypersensitivity.
- Presentation: Intense bilateral itching (hallmark), watery discharge, chemosis (conjunctival edema), and cobblestone papillae on the upper tarsal conjunctiva.
- Management: Trigger avoidance. First-line is topical antihistamines/mast cell stabilizers like Olopatadine or Ketotifen.
Cataracts
Pathophysiology & Risk Factors
A cataract is a progressive, painless, typically bilateral opacification of the crystalline lens. Over time, oxidative damage and protein aggregation cloud the lens. Key risk factors include:
- Aging: The most common cause.
- Systemic diseases: Diabetes mellitus.
- Medications: Chronic systemic or topical corticosteroid use.
- Environmental: UVB radiation, cigarette smoking, and trauma.
Clinical Presentation & Diagnostic Workup
Patients report a gradual, painless decline in visual acuity. Classic complaints include difficulty driving at night due to headlight glare, reduced color sensitivity, and needing brighter reading light. On exam, the lens appears cloudy. Dilated ophthalmoscopy demonstrates a diminished or absent red reflex. Slit-lamp examination confirms lens opacification.
Clinical Management
- Early Stage: Prescription glasses and brighter lighting.
- Definitive Treatment: Surgical cataract extraction (phacoemulsification followed by intraocular lens implantation). Indicated when visual impairment interferes with activities of daily living.
Classic PANCE Traps & Clinical Pearls
- Mydriatic Warning: Never administer dilating drops to patients with narrow angles; this can trigger acute angle-closure.
- Steroid Danger: Avoid prescribing topical corticosteroids, as they can cause corneal melting in herpes simplex or lead to steroid-induced glaucoma.
- Pseudomonas Rule: Always prescribe fluoroquinolones in contact lens wearers to cover Pseudomonas.
- Absent Red Reflex: In children, an absent red reflex is retinoblastoma until proven otherwise; in older adults, it is most commonly a cataract.
Ophthalmic Disorders Comparison
| Condition | Primary Features | Classic Exam Findings | Initial Management |
|---|---|---|---|
| Acute Angle-Closure Glaucoma | Sudden unilateral pain, halos, nausea | Steamy cornea, mid-dilated pupil, high IOP | Timolol + Apraclonidine + Pilocarpine + IV Acetazolamide |
| Bacterial Conjunctivitis | Purulent discharge, eyes glued shut | Lid crusting, conjunctival injection | Erythromycin (non-contact lens) or Ciprofloxacin (contact lens) |
| Viral Conjunctivitis | Watery discharge, highly contagious | Palpebral follicles, preauricular adenopathy | Supportive (cool compresses) |
| Allergic Conjunctivitis | Intense bilateral itching | Chemosis, cobblestone papillae | Topical Olopatadine |
| Cataracts | Gradual, painless vision loss, glare | Cloudy lens, loss of red reflex | Surgical extraction with IOL |
Retinal Detachment
Retinal detachment is an ophthalmic emergency in which the neurosensory retina separates from the underlying retinal pigment epithelium. Risk factors include high myopia, posterior vitreous detachment, trauma, and prior cataract surgery. Presentation: sudden onset of new floaters, flashes of light (photopsia), and a "curtain" or "veil" descending over the visual field. Diagnosis is by fundoscopy (revealing a detached, elevated retina) and ocular ultrasound. Treatment: immediate ophthalmology referral for laser retinopexy, cryotherapy, pneumatic retinopexy, scleral buckling, or vitrectomy. Delayed treatment risks permanent vision loss.
A 63-year-old female presents to the emergency department with sudden, severe headache, left eye pain, and nausea after walking into a movie theater. On examination, the left eye has a ciliary flush, the cornea is hazy, and the left pupil is 5 mm, fixed, and nonreactive. The left eye feels hard to palpation. What is the most appropriate initial combination of pharmacotherapy to reduce intraocular pressure in this patient?
A 24-year-old male contact lens wearer presents to the urgent care clinic with a 2-day history of acute redness, foreign body sensation, and constant thick, yellow-green purulent discharge from his right eye. On examination, the right conjunctiva is injected, and there is significant purulent crusting on the eyelids. The cornea is clear, and visual acuity is normal. Which of the following is the most appropriate first-line pharmacotherapy?
A 72-year-old male presents with a gradual, progressive decline in his vision over the past two years, describing it as blurry and washed out. He particularly struggles with driving at night due to disabling glare from oncoming headlights. He denies any pain, redness, or discharge. On physical examination, there is a bilateral grey-white cloudiness visible within the pupils, and ophthalmoscopy demonstrates a diminished red reflex bilaterally. Which of the following is the most common risk factor for the development of this patient's condition?