18.3 Acute Ophthalmologic Emergencies

ABFM Family Medicine Certification Study Guide Exam

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1 Chapter 1: Exam Structure, Blueprint & Clinical Decision-Making

1.1 Exam Blueprint, FMCLA vs. One-Day Exam & Board Scoring 1.2 Clinical Reasoning, Test-Taking Strategy & Ambiguity Management 1.3 Evidence-Based Medicine & Clinical Practice Guidelines in Primary Care

2 Chapter 2: Healthcare Systems, Practice Management & Quality

2.1 Practice Management, Billing, Coding & Documentation 2.2 Quality Improvement, Patient Safety & Diagnostic Stewardship 2.3 Interprofessional Team-Based Care & Care Coordination

3 Chapter 3: Ethics, Law, Biostatistics & Health Equity

3.1 Medical Ethics, Informed Consent & Surrogate Decision-Making 3.2 Biostatistics, Clinical Epidemiology & Diagnostic Test Interpretation 3.3 Social Determinants of Health, Health Equity & Cultural Humility 3.4 Physician Wellness, Burnout Prevention & Professionalism

4 Chapter 4: Lifestyle Counseling & Behavior Change

4.1 Alcohol Use Screening & Brief Intervention 4.2 Illicit Drug & Cannabis Counseling 4.3 Tobacco & Vaping Cessation Counseling

5 Chapter 5: Nutrition, Physical Activity & Chronic Disease Prevention

5.1 Dietary Counseling for Obesity & Chronic Disease Prevention 5.2 Exercise Prescription & Physical Activity Counseling 5.3 Genetic Risk Assessment & Family History Counseling

6 Chapter 6: Routine Adult Immunizations

6.1 ACIP Adult Respiratory Vaccines: Influenza, COVID-19, RSV & Pneumococcal 6.2 ACIP Adult Non-Respiratory Vaccines: Tdap, Shingrix, HPV & Hep B 6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise

7 Chapter 7: Pediatric Health Maintenance & Surveillance

7.1 Newborn Examination & Early Postnatal Care 7.2 Well-Child Care, Developmental Surveillance & Milestones 7.3 Pediatric & Adolescent Screening: Vision, Hearing, Anemia & Lead 7.4 Pediatric Oral Health, Dental Screening & Fluoride

8 Chapter 8: Behavioral Health & Safety Screening

8.1 Primary Care Depression, Anxiety & Behavioral Health Screening 8.2 Domestic Violence, Intimate Partner Violence & Firearm Safety 8.3 Occupational Health & Recreational Safety Counseling

9 Chapter 9: Adult Preventive Screening: Cardiovascular & Metabolic

9.1 Cardiovascular Disease & Hypertension Screening 9.2 Type 2 Diabetes Screening & Prediabetes Risk Stratification 9.3 Abdominal Aortic Aneurysm & Osteoporosis Screening

10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

10.1 Breast Cancer Screening & Risk-Assessment 10.2 Cervical Cancer Screening & ASCCP Algorithms 10.3 Skin Cancer Clinical Assessment & Counseling

11 Chapter 11: Adult Cancer Screening: Colorectal, Lung & Prostate

11.1 Colorectal Cancer Screening Modalities & Intervals 11.2 Lung Cancer Screening with Low-Dose CT 11.3 Prostate Cancer Screening & Shared Decision-Making

12 Chapter 12: Sexual Health, Infectious Disease Screening & Contraception

12.1 Sexual Health Counseling & Risk-Reduction Strategies 12.2 STI Screening: Chlamydia, Gonorrhea, Syphilis & Trichomoniasis 12.3 Bloodborne Infectious Disease Screening: HIV & Hepatitis C

13 Chapter 13: Reproductive Life Planning, Lactation & Preoperative Care

13.1 Preconception Planning & Comprehensive Contraception Management 13.2 Lactation Support & Breastfeeding Counseling 13.3 Preoperative Medical Evaluation & Pre-Participation Sports Exam

14 Chapter 14: Emergent Cardiovascular Conditions

14.1 Acute Coronary Syndromes & Myocardial Infarction 14.2 Acute Chest Pain Risk Stratification & Triage 14.3 Acute or Critical Valvular Heart Emergencies

15 Chapter 15: Cardiac Arrhythmias, Heart Failure & Hypertensive Crises

15.1 Acute Atrial & Ventricular Arrhythmias 15.2 Acute Decompensated Heart Failure & Cardiogenic Shock 15.3 Hypertensive Emergency & Urgency Management

16 Chapter 16: Vascular & Thromboembolic Emergencies

16.1 Pulmonary Embolism & Deep Vein Thrombosis 16.2 Acute Aortic Syndromes & Peripheral Vascular Emergencies 16.3 Critical Limb Ischemia & Acute Arterial Occlusion

17 Chapter 17: Neurologic Emergencies: Stroke & Altered Consciousness

17.1 Acute Ischemic Stroke & Intracranial Hemorrhage 17.2 Syncope Evaluation & Status Epilepticus 17.3 Acute Delirium, Encephalopathy & Severe Confusion

18 Chapter 18: Neurologic Trauma & Acute Cranial Emergencies

18.1 Concussion, Moderate-to-Severe TBI & Intracranial Injury 18.2 Thunderclap & Acute Severe Secondary Headaches 18.3 Acute Ophthalmologic Emergencies

19 Chapter 19: Acute Abdominal, Pelvic & Gastrointestinal Emergencies

19.1 Acute Abdominal & Pelvic Pain Triage 19.2 Upper & Lower Gastrointestinal Bleeding 19.3 Acute Hepatic Failure, Cholangitis & Severe Jaundice

20 Chapter 20: Acute Pulmonary & Airway Emergencies

20.1 Acute Hypoxic Respiratory Failure & ARDS 20.2 Severe Community-Acquired Pneumonia & Empyema 20.3 Acute Severe Epistaxis & Airway Obstruction

21 Chapter 21: Acute Traumatic Injuries & Wound Care

21.1 Major Trauma Resuscitation & Initial Assessment 21.2 Burn Assessment, Inhalation Injury & Resuscitation 21.3 Laceration Management, Complex Wounds & Animal Bites

22 Chapter 22: Acute Orthopedic & Musculoskeletal Emergencies

22.1 Acute Ambulatory Fractures & Initial Splinting 22.2 Compartment Syndrome & Major Orthopedic Trauma 22.3 Septic Arthritis & Acute Microcrystalline Crises

23 Chapter 23: Severe Infections, Sepsis & Systemic Emergencies

23.1 Sepsis, Septic Shock & Initial Fluid Resuscitation 23.2 Necrotizing Soft Tissue Infections & Severe CNS Infections 23.3 Anaphylaxis Diagnosis, Epinephrine Dosing & Airway Protection

24 Chapter 24: Metabolic, Endocrine & Electrolyte Emergencies

24.1 Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State 24.2 Critical Electrolyte Emergencies: Dyskalemias & Dysnatremias 24.3 Severe Calcium Abnormalities & Acute Adrenal Crisis

25 Chapter 25: Hematologic, Urologic & Dental Emergencies

25.1 Severe Symptomatic Anemias & Coagulopathic Emergencies 25.2 Testicular Torsion, Priapism & Acute Urinary Retention 25.3 Urgent Odontogenic Infections & Dental Trauma

26 Chapter 26: Psychiatric, Behavioral & Obstetric/Gynecologic Emergencies

26.1 Suicidal Ideation, Acute Agitation & Behavioral Emergencies 26.2 Acute Physical & Sexual Assault Care 26.3 Life-Threatening Vaginal Bleeding & Ectopic Pregnancy 26.4 Environmental Heat Stroke & Severe Hypothermia

27 Chapter 27: Acute Head, Neck & Neurologic Symptoms

27.1 Primary Acute Headaches: Migraine, Tension & Cluster 27.2 Concussion & Minor Closed Head Injury Evaluation 27.3 Transient Ischemic Attack Evaluation & ABCD2 Risk Scoring

28 Chapter 28: Acute Cranial Nerves, Hearing & Sensory Symptoms

28.1 Peripheral Neuropathies: Bell's Palsy, Carpal Tunnel & Radiculopathy 28.2 Acute Tinnitus, Sudden Sensorineural Hearing Loss & Cerumen Impaction 28.3 Acute Dizziness, Benign Paroxysmal Positional Vertigo & Vestibular Neuritis

29 Chapter 29: Acute Upper Respiratory Tract Infections

29.1 Acute Viral Rhinosinusitis vs. Bacterial Rhinosinusitis 29.2 Acute Pharyngitis: Group A Streptococcus & Centor Criteria 29.3 Acute Otitis Media, Otitis Externa & Serous Effusion

30 Chapter 30: Acute Lower Respiratory Infections & Cough

30.1 Influenza, COVID-19 & Viral Respiratory Syndromes 30.2 Acute Bronchitis & Lower Respiratory Tract Infections 30.3 Ambulatory Community-Acquired Pneumonia

31 Chapter 31: Allergic, Nasal & Non-Infectious Pulmonary Conditions

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions 31.2 Acute Dyspnea in Ambulatory Care 31.3 Interstitial Lung Diseases & Sarcoidosis Presentation

32 Chapter 32: Acute Chest, Cardiac & Vascular Symptoms

32.1 Palpitations Evaluation & Arrhythmia Triage in Primary Care 32.2 Deep Vein Thrombosis & Superficial Thrombophlebitis 32.3 Ambulatory Hypotension & Orthostasis Evaluation

33 Chapter 33: Acute Upper Gastrointestinal Conditions

33.1 Peptic Ulcer Disease & Gastritis 33.2 Dysphagia, Esophagitis & Acute Esophageal Disorders 33.3 Acute Nausea, Vomiting & Foodborne Illness

34 Chapter 34: Acute Lower Gastrointestinal Conditions

34.1 Acute Infectious Diarrhea & Gastroenteritis 34.2 Acute Constipation & Functional Bowel Changes 34.3 Ano-Rectal Disorders: Hemorrhoids, Fissures, Abscesses & Pruritus Ani

35 Chapter 35: Inflammatory, Functional & Malabsorptive GI Disorders

35.1 Acute Flares of Inflammatory Bowel Disease 35.2 Irritable Bowel Syndrome: Diagnosis, Subtyping & Management 35.3 Celiac Disease & Malabsorption Syndromes

36 Chapter 36: Acute Abdominal, Hepatic & Biliary Disorders

36.1 Ambulatory Abdominal & Pelvic Pain Triage 36.2 Acute Cholecystitis, Biliary Colic & Pancreatitis 36.3 Acute Liver Injury & Viral Hepatitis

37 Chapter 37: Acute Abdominal Wall, Hernias & Dental Conditions

37.1 Abdominal Wall, Inguinal & Ventral Hernias 37.2 Acute Dental Pain, Odontogenic Abscess & Aphthous Ulcers 37.3 Acute Edema: Unilateral vs. Bilateral Diagnostic Evaluation

38 Chapter 38: Acute Infectious Dermatoses

38.1 Bacterial Skin Infections: Impetigo, Cellulitis & Cutaneous Abscesses 38.2 Fungal Skin Infections: Tinea Corporis, Cruris, Pedis & Onychomycosis 38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

39 Chapter 39: Inflammatory, Allergic & Autoimmune Dermatoses

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares 39.2 Non-Infectious Rashes: Urticaria, Drug Eruptions & Erythema Multiforme 39.3 Cutaneous Malignancies & Premalignant Lesions: AK, BCC, SCC & Melanoma

40 Chapter 40: Acute Shoulder, Elbow & Upper Extremity Injuries

40.1 Rotator Cuff Pathology, Tendinopathy & Shoulder Impingement 40.2 Lateral & Medial Epicondylitis, Olecranon Bursitis & Elbow Sprains 40.3 Wrist & Hand Soft-Tissue Injuries: De Quervain, TFCC & Finger Sprains

41 Chapter 41: Acute Knee, Ankle & Lower Extremity Injuries

41.1 Meniscal Tears, Ligamentous Knee Injuries & Patellofemoral Pain 41.2 Ankle Sprains, Ottawa Ankle Rules & Achilles Tendinopathy 41.3 Plantar Fasciitis, Shin Splints & Overuse Syndromes

42 Chapter 42: Acute Ambulatory Fractures & Dislocations

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures 42.2 Metatarsal, Clavicle & Common Lower Extremity Fractures 42.3 Joint Dislocation Management: Nursemaid's Elbow & Shoulder Subluxation

43 Chapter 43: Acute Axial Musculoskeletal Pain & Falls

43.1 Acute Low Back Pain: Red Flags, Strain & Disc Herniation 43.2 Acute Cervical Strain, Whiplash & Axial Neck Pain 43.3 Evaluation of Falls in Ambulatory & Older Patients

44 Chapter 44: Acute Inflammatory Arthropathies & Generalized Pain

44.1 Acute Inflammatory Arthritis & Spondyloarthropathies 44.2 Myalgias, Rhabdomyolysis & Post-Viral Pain Syndromes 44.3 Acute Non-Headache Pain Management Strategies

45 Chapter 45: Acute Renal, Urinary & Genitourinary Conditions

45.1 Uncomplicated UTI, Pyelonephritis & Acute Urethritis 45.2 Hematuria Workup & Glomerulonephritis 45.3 Nephrolithiasis & Acute Urinary Tract Obstruction

46 Chapter 46: Acute Male Genitourinary & Prostatic Conditions

46.1 Acute Prostatitis, Epididymitis & Orchitis 46.2 Acute Scrotal Pain: Torsion vs Appendage, BPH & Male Genital Emergencies 46.3 Acute Urinary Retention & Incontinence Evaluation

47 Chapter 47: Acute Women's Health & Early Pregnancy Care

47.1 Early Pregnancy Diagnosis, Dating & Initial Complications 47.2 Abnormal Uterine Bleeding & Acute Menstrual Disorders 47.3 Premenstrual Syndrome & Premenstrual Dysphoric Disorder

48 Chapter 48: Breast Disorders, STIs & Pediatric Elimination

48.1 Palpable Breast Mass, Mastitis & Nipple Discharge 48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines 48.3 Pediatric Enuresis & Encopresis

49 Chapter 49: Systemic Signs, Metabolic Dysregulation & Miscellaneous Infections

49.1 Acute Fever, Sepsis Screening & FUO in Primary Care 49.2 Acute Hyperglycemia & Symptomatic Hypoglycemia 49.3 Electrolyte Abnormalities: Mild-to-Moderate Disturbances 49.4 Vector-Borne, Tick-Borne & Rickettsial Illnesses

50 Chapter 50: Chronic Cardiovascular Diseases: Hypertension & Ischemia

50.1 Essential Hypertension Management: 2025 AHA/ACC Guideline & JNC Strategies 50.2 Chronic Coronary Artery Disease & Post-MI Secondary Prevention 50.3 Chronic Heart Failure: HFrEF, HFpEF & Quadruple GDMT

51 Chapter 51: Chronic Vascular, Valvular & Dyslipidemic Diseases

51.1 Peripheral Arterial Disease & Claudication 51.2 Chronic Valvular Heart Disease & Murmur Evaluation 51.3 Lipid Disorders & ASCVD Risk-Based Statin Therapy

52 Chapter 52: Chronic Respiratory Diseases: Asthma & COPD

52.1 Chronic Asthma Management: GINA Stepwise SMART Therapy 52.2 Chronic Obstructive Pulmonary Disease: GOLD Recommendations 52.3 Solitary Pulmonary Nodule Evaluation & Fleischner Society Criteria

53 Chapter 53: Chronic Metabolic Diseases: Diabetes Mellitus

53.1 Type 2 Diabetes Management: ADA Pharmacotherapy Algorithms 53.2 Type 1 Diabetes: Basal-Bolus Insulin, CGMs & Diabetic Complications 53.3 Diabetic Microvascular & Macrovascular Disease Surveillance

54 Chapter 54: Obesity, Nutrition & Metabolic Bone Diseases

54.1 Medical & Behavioral Management of Obesity & Incretin Mimetics 54.2 Osteoporosis & Metabolic Bone Disease: DEXA, FRAX & Antiresorptives 54.3 Nutritional Deficiencies: Vitamin D, B12, Iron & Malnutrition

55 Chapter 55: Chronic Endocrine Disorders

55.1 Primary & Subclinical Hypothyroidism, Hyperthyroidism & Nodules 55.2 Adrenal Disorders: Addison's Disease & Cushing's Syndrome 55.3 Hypercalcemia, Hyperparathyroidism & Pituitary Disorders

56 Chapter 56: Chronic Kidney Disease & Venous Disorders

56.1 Chronic Kidney Disease: KDIGO Staging & Renoprotective Therapy 56.2 Chronic Venous Insufficiency, Stasis Dermatitis & Lymphedema 56.3 Chronic Electrolyte & Acid-Base Management in CKD

57 Chapter 57: Chronic Gastrointestinal & Hepatic Diseases

57.1 Gastroesophageal Reflux Disease, Barrett's Esophagus & Dyspepsia 57.2 Chronic Liver Disease: MASLD/NAFLD, Cirrhosis & Portal Hypertension 57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

58 Chapter 58: Colorectal Surveillance & Chronic Pancreaticobiliary Care

58.1 Post-Polypectomy Colorectal Polyp Surveillance Guidelines 58.2 Chronic Pancreatitis & Exocrine Pancreatic Insufficiency 58.3 Chronic Nausea, Gastroparesis & Functional GI Disorders

59 Chapter 59: Chronic Musculoskeletal & Rheumatologic Disorders

59.1 Osteoarthritis: Hip, Knee & Hand Management 59.2 Spinal Conditions: Spinal Stenosis, Spondylolisthesis & Compression Fractures 59.3 Chronic Myopathies & Fibromyalgia Syndrome

60 Chapter 60: Chronic Neurologic & Neurodegenerative Disorders

60.1 Dementia: Alzheimer's, Vascular & Lewy Body Disease 60.2 Parkinson's Disease & Essential Tremor 60.3 Epilepsy: Chronic Antiseizure Medications & Post-Stroke Care

61 Chapter 61: Chronic Peripheral Nerves, Pain & Sensory Disorders

61.1 Diabetic & Chronic Peripheral Neuropathies 61.2 Chronic Pain Syndromes & Chronic Daily Headaches 61.3 Chronic Tinnitus, Presbycusis & Persistent Dizziness

62 Chapter 62: Chronic Psychiatric Disorders

62.1 Major Depressive Disorder & Generalized Anxiety Disorder 62.2 Bipolar Disorder: Maintenance Pharmacotherapy & Lithium Monitoring 62.3 Adult & Pediatric Attention-Deficit/Hyperactivity Disorder

63 Chapter 63: Chronic Behavioral Health & Neurodevelopmental Conditions

63.1 Chronic Behavioral Conditions: PTSD, OCD & Somatization 63.2 Autism Spectrum Disorder & Intellectual Disabilities 63.3 Eating Disorders: Anorexia Nervosa, Bulimia & Binge Eating

64 Chapter 64: Chronic Substance Use Disorders & Tobacco Cessation

64.1 Alcohol Use Disorder: Pharmacotherapy & Relapse Prevention 64.2 Opioid & Stimulant Use Disorders: MOUD & Harm Reduction 64.3 Longitudinal Tobacco Cessation Pharmacotherapy

65 Chapter 65: Chronic Dermatologic Conditions

65.1 Acne Vulgaris, Rosacea & Seborrheic Dermatitis 65.2 Chronic Plaque Psoriasis & Biologic Therapies 65.3 Chronic Eczema, Hidradenitis Suppurativa & Cutaneous Lupus

66 Chapter 66: Chronic Reproductive, Infectious & Geriatric Special Care

66.1 Chronic Menstrual Disorders, Infertility & Sexual Dysfunction 66.2 Menopause Management & Hormone Replacement Therapy 66.3 Chronic HIV Infection Management & Primary Care Integration 66.4 Gender-Affirming Primary Care & Hormone Therapy 66.5 Advance Care Planning, Palliative Care & End-of-Life Symptom Control

67 Chapter 67: Continuity Care: Sleep, Fatigue, Cancer, Pregnancy & the Adult Preventive Visit

67.1 Chronic Insomnia & Obstructive Sleep Apnea 67.2 Chronic Malaise, Fatigue & ME/CFS 67.3 Primary Care During Cancer Treatment & Survivorship 67.4 Routine Prenatal Care & Longitudinal Pregnancy Management 67.5 The Periodic Adult Health Examination & Medicare Annual Wellness Visit

18.3 Acute Ophthalmologic Emergencies

Key Takeaways Explain This Topic AI

Central Retinal Artery Occlusion (CRAO) is an acute ischemic retinal stroke presenting with sudden, profound, painless monocular vision loss; physical exam reveals a pale, ischemic retina with a pathognomonic foveal 'cherry-red spot' and an afferent pupillary defect (RAPD / Marcus Gunn pupil), mandating urgent ocular decompression and immediate stroke code activation.

Central Retinal Vein Occlusion (CRVO) presents with painless subacute to sudden vision loss characterized by a classic 'blood and thunder' fundus (extensive flame hemorrhages in all four quadrants, venous engorgement, cotton-wool spots, and disc edema), managed with urgent ophthalmology referral and anti-VEGF or corticosteroid injections for macular edema.

Retinal detachment classically presents with photopsia (flashing lights), a sudden shower of dark floaters, and an advancing curtain or veil over the visual field; funduscopy demonstrates an elevated, undulating, corrugated grey retina, requiring emergency vitreoretinal surgical intervention to salvage macular function.

Acute angle-closure glaucoma is an ophthalmic emergency presenting with excruciating unilateral eye pain, headache, nausea, steamy cornea, fixed mid-dilated pupil, and marked intraocular pressure (IOP >40–50 mm Hg; normal 10–21 mm Hg); immediate medical treatment includes topical beta-blockers, alpha-2 agonists, topical steroids, IV acetazolamide, and IV mannitol, followed by pilocarpine once IOP <30 mm Hg, with definitive bilateral laser peripheral iridotomy.

Ocular chemical burns require instantaneous copious irrigation with normal saline or Lactated Ringer's until conjunctival pH is neutral (7.0–7.2), with alkali burns being far more devastating than acid burns due to rapid liquefactive necrosis; orbital cellulitis is differentiated from preseptal cellulitis by proptosis, painful ophthalmoplegia, and visual impairment, requiring urgent contrast CT of the orbits and broad-spectrum intravenous antibiotics.

Last updated: September 2026

Acute Painless Monocular Vision Loss: CRAO, CRVO & Retinal Detachment

Acute, painless monocular visual loss is a terrifying symptom that demands urgent bedside evaluation. The primary clinical priority is distinguishing between an acute vascular occlusion (arterial vs venous) and a mechanical retinal detachment.

Comparison of Acute Painless Visual Loss Etiologies

Feature Central Retinal Artery Occlusion (CRAO) Central Retinal Vein Occlusion (CRVO) Rhegmatogenous Retinal Detachment (RD)

Pathophysiology Embolic or thrombotic occlusion of the central retinal artery (branch of ophthalmic artery); an ischemic stroke of the retina Thrombotic occlusion of the central retinal vein at or near the lamina cribrosa; venous stasis and engorgement Full-thickness neurosensory retinal tear allowing liquefied vitreous fluid to dissect into the subretinal space

Predisposing Conditions Carotid artery atherosclerosis, atrial fibrillation, cardiac valvular vegetations, giant cell arteritis (GCA / temporal arteritis in age >50) Advanced age, chronic hypertension, diabetes mellitus, hyperlipidemia, glaucoma, hyperviscosity states Severe myopia, previous cataract extraction, vitreous detachment, ocular trauma, lattice degeneration

Visual Symptoms Sudden, profound, catastrophic vision loss within seconds ("curtain falling into total darkness"); visual acuity reduced to counting fingers or light perception Subacute or sudden variable visual loss; ranges from mild blurring to severe reduction; often noticed upon awakening Photopsia (flashes of light), sudden burst of black floaters ("cobwebs"), followed by a progressive dark shadow, curtain, or veil across vision

Pupillary Exam Relative Afferent Pupillary Defect (RAPD / Marcus Gunn pupil) present in the affected eye Mild RAPD may be present in severe ischemic CRVO; normal in non-ischemic RAPD present if detachment is extensive or involves the macula

Pathognomonic Funduscopic Findings Diffuse retinal whitening/pallor due to ischemic intracellular edema; "Cherry-red spot" at the fovea (foveal center lacks inner retinal layers, allowing red choroidal vascularity to shine through); "Boxcarring" / cattle-trucking of retinal arterioles "Blood and thunder" appearance : Extensive flame-shaped and blot hemorrhages across all four quadrants , marked venous tortuosity/engorgement, cotton-wool spots, disc edema Elevated, corrugated, folding, billowing grey retina undulating with eye movement; loss of underlying choroidal vascular pattern

Emergency Management True ocular emergency (retinal viability ~90–240 minutes):; • Immediate digital ocular massage; • Anterior chamber paracentesis; • Rebreathing / carbogen (vasodilation); • Topical timolol / apraclonidine; • Emergent Stroke Code activation ; • Rule out GCA (ESR/CRP; IV steroids if elevated) Urgent ophthalmology referral:; • Intravitreal anti-VEGF injections (aflibercept, ranibizumab) or steroid implants for macular edema; • Panretinal photocoagulation (PRP) if neovascularization occurs; • High risk for neovascular glaucoma ("90-day glaucoma") Emergent vitreoretinal consultation:; • Keep patient supine; head positioned to keep tear dependent; • Keep strictly NPO for surgery; • Vitreoretinal surgery: Pneumatic retinopexy, scleral buckle, or pars plana vitrectomy; • Emergency if "Macula-On" (saves central vision)

Central Retinal Artery Occlusion as a Stroke Equivalent

CRAO represents an acute ischemic stroke of the central nervous system. Modern guidelines from the American Heart Association / American Stroke Association (AHA/ASA) mandate immediate Stroke Code activation for patients presenting within the acute therapeutic window. Diagnostic workup must include:

Brain MRI with diffusion-weighted imaging (DWI; identifies silent concurrent cerebral cortical infarctions in ~25%);

Carotid duplex ultrasonography or CTA head/neck to evaluate ipsilateral carotid stenosis requiring urgent carotid endarterectomy;

Echocardiography (transthoracic or transesophageal) and cardiac telemetry to detect cardioembolic sources (atrial fibrillation, patent foramen ovale, left ventricular mural thrombus);

Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP) in patients aged ≥50 years to exclude arteritic CRAO secondary to Giant Cell Arteritis (GCA) . If GCA is suspected, administer immediate high-dose IV methylprednisolone (1 g daily for 3 days) without waiting for temporal artery biopsy, to prevent irreversible bilateral blindness.

Acute Angle-Closure Glaucoma: Pathophysiology & Emergency Therapy

Acute Angle-Closure Glaucoma (AACG) is an ophthalmic emergency caused by sudden mechanical blockage of aqueous humor drainage through the trabecular meshwork into the canal of Schlemm, precipitating a dangerous spike in intraocular pressure (IOP) from normal levels (10–21 mm Hg) to 40–80 mm Hg .

Mechanism & Precipitating Triggers

Pupillary Block : In anatomically predisposed eyes with shallow anterior chambers (hyperopia/farsightedness, advanced cataracts, elderly, Asian and Inuit descent), contact between the posterior iris and the anterior lens blocks flow of aqueous humor from the posterior chamber into the anterior chamber.

Iris Root Crowding : As aqueous fluid builds behind the iris, pressure bows the peripheral iris forward (iris bombé) against the trabecular meshwork, sealing the iridocorneal angle.

Precipitating Factors : Mid-dilation of the pupil maximizes iris-lens contact and bunches the peripheral iris into the angle:

Low-ambient light environments (e.g., walking into a dark movie theater or dim evening room);

Pharmacological agents with anticholinergic properties (atropine, scopolamine, ipratropium, oxybutynin, diphenhydramine, tricyclic antidepressants);

Sympathomimetic agents (pseudoephedrine, phenylephrine, ephedrine);

Sulfa-based medications causing choroidal effusion (topiramate).

Clinical Presentation & Cardinal Examination Findings

Symptoms : Severe, excruciating, boring unilateral ocular and periorbital pain; radiating ipsilateral frontal headache; blurred vision and rainbow-colored halos around lights (caused by corneal epithelial edema scattering light); severe nausea, profuse vomiting, and abdominal pain (frequently mistaken for acute gastroenteritis, migraine, or an acute surgical abdomen).

Physical Examination Findings :

Ciliary Flush : Violaceous, deep injection surrounding the limbus (circumcorneal injection);
Corneal Edema : Diffusely hazy, cloudy, "steamy" cornea with complete loss of normal corneal luster;

Pupillary Abnormality : Fixed, mid-dilated (4 to 6 mm), vertically oval pupil that is unreactive to direct light and accommodation;

Shallow Anterior Chamber : Slit-lamp exam shows slit-like space between cornea and iris; oblique penlight illumination casts a prominent nasal iris shadow;

Induration : Digital palpation through closed eyelids reveals a rock-hard globe compared to the normal contralateral eye;

Tonometry Confirmation : Intraocular pressure dramatically elevated (typically >40–70 mm Hg ; normal 10–21 mm Hg).

Stepwise Medical Pharmacotherapy Regimen

Emergency treatment aims to rapidly lower intraocular pressure, clear corneal edema, and break the pupillary block: ACUTE ANGLE-CLOSURE GLAUCOMA COCKTAIL

┌────────────────────────────────────────────────────────────────────────┐
│ STEP 1: SUPPRESS AQUEOUS HUMOR PRODUCTION (Triple Topical Drops) │
│ • Timolol 0.5% (Beta-blocker): 1 drop │
│ • Apraclonidine 1% (Alpha-2 agonist): 1 drop │
│ • Prednisolone acetate 1% (Topical steroid): 1 drop (reduces uveitis) │
└───────────────────────────────────┬────────────────────────────────────┘
│
▼
┌────────────────────────────────────────────────────────────────────────┐
│ STEP 2: SYSTEMIC CARBONIC ANHYDRASE INHIBITION │
│ • Acetazolamide 500 mg IV bolus (or 500 mg PO if tolerated) │
│ • Blocks ciliary body carbonic anhydrase; halts aqueous synthesis │
│ • Avoid in documented severe sulfa allergy │
└───────────────────────────────────┬────────────────────────────────────┘
│
▼
┌────────────────────────────────────────────────────────────────────────┐
│ STEP 3: SYSTEMIC OSMOTIC DEHYDRATION OF VITREOUS (If IOP >50 or N/V) │
│ • IV Mannitol 1.0 to 2.0 g/kg infused over 30-45 minutes │
│ • Creates osmotic gradient, pulling fluid from vitreous into blood │
└───────────────────────────────────┬────────────────────────────────────┘
│
▼
┌────────────────────────────────────────────────────────────────────────┐
│ STEP 4: MIOTIC AGENT (STRICT TIMING REQUIREMENT) │
│ • Pilocarpine 1% to 2%: 1 drop every 15 minutes for 2 doses │
│ • CRITICAL EXAM RULE: Administer ONLY AFTER IOP drops <30 mm Hg │
│ • Reason: At IOP >40-50, iris sphincter is ischemic and paralyzed; │
│ premature pilocarpine is ineffective and worsens pupillary block │
└───────────────────────────────────┬────────────────────────────────────┘
│
▼
┌────────────────────────────────────────────────────────────────────────┐
│ STEP 5: DEFINITIVE SURGICAL / LASER CURE │
│ • Bilateral Laser Peripheral Iridotomy (LPI) │
│ • Mandatory: Prophylactic LPI of the contralateral (fellow) eye! │
│ • >50% of fellow eyes develop angle closure within 5 years untreated │
└────────────────────────────────────────────────────────────────────────┘
Chemical Ocular Burns: Alkali vs Acid & Copious Irrigation

Chemical ocular injury is one of the few true ophthalmic emergencies where therapy must precede history taking, examination, or visual acuity measurement.

Alkali vs Acid: Pathophysiology

Chemical Category Common Agents Mechanism of Tissue Destruction Clinical Severity & Penetration

Alkali Burns ; (Most Dangerous) Ammonia (fertilizers, cleaning sprays), Lye / Sodium hydroxide (drain cleaners, oven cleaners), Lime / Calcium hydroxide (plaster, mortar, cement), Potassium hydroxide Liquefactive Necrosis : Saponifies cell membrane fatty acids, denatures collagen, and rapidly penetrates corneal stroma into the anterior chamber within minutes. Destroys limbal stem cells and trabecular meshwork Extreme Severity : Deep, rapid penetration. Perilimbal conjunctival blanching ( "porcelain white eye" ) indicates total ischemia of limbal blood supply and carries an ominous visual prognosis

Acid Burns Battery acid (sulfuric acid), Swimming pool cleaners (hydrochloric acid), Vinegar / Acetic acid, Glass etching fluid (hydrofluoric acid) Coagulative Necrosis : Denatures and precipitates corneal stromal proteins, forming an insoluble proteinaceous coagulum barrier that limits further chemical penetration Moderate Severity : Typically superficial and self-limiting due to the protective protein barrier.; Exception : Hydrofluoric acid penetrates deeply like an alkali due to fluoride ion cytotoxicity

Emergency Copious Irrigation Protocol

DO NOT WAIT : Never delay irrigation to test visual acuity, obtain an in-depth medical history, or await ophthalmology consultation. Time to irrigation is the single greatest determinant of visual recovery.

Instill Topical Anesthetic : Instill 1 to 2 drops of proparacaine 0.5% or tetracaine 0.5% to overcome blepharospasm.

Initiate Irrigation : Connect a Morgan lens or standard intravenous tubing to Lactated Ringer's (preferred, physiological pH 6.0–7.5) or 0.9% Normal Saline. Irrigate continuously with 1 to 2 liters of fluid over 30 to 60 minutes.

Sweep Fornices : Evert upper and lower eyelids. Particulate chemical matter (especially lime, cement, mortar, or plaster) embeds in the conjunctival fornices and continually leaches chemical into tears. Mechanically sweep the fornices with a moistened cotton swab.

Document Neutral pH Endpoint : Stop irrigation; wait 5 to 10 minutes to allow tear film equilibration. Touch a universal pH litmus strip to the inferior conjunctival fornix. The target endpoint is a neutral pH of 7.0 to 7.2 . Continue irrigation until neutrality is achieved. Re-check pH 30 minutes later to ensure no rebound shift from hidden chemical particles.

Open Globe Injury & Penetrating Ocular Trauma

An open globe injury is a full-thickness disruption of the cornea, sclera, or both, resulting from blunt rupture or penetrating projectile trauma.

Cardinal Physical Examination Signs

Positive Seidel Test : Apply concentrated moistened fluorescein dye directly over the suspected laceration under cobalt blue light. Escaping clear aqueous humor dilutes and washes away the dark orange fluorescein, appearing as a bright green river or waterfall flowing downward under the slit lamp.

Peaked / Teardrop Pupil : The pupil is distorted and points directly toward the site of corneal or scleral rupture.

Uveal Tissue Prolapse : Brownish, pigmented tissue (iris, ciliary body, or choroid) protruding through the wound defect.

Shallow / Flat Anterior Chamber : Collapse of anterior chamber depth compared to the unaffected eye.

Bullous 360-Degree Subconjunctival Hemorrhage : Frequently conceals an underlying posterior scleral rupture.

Strict "Do No Harm" Management Protocol

Absolute Contraindication to Pressure : DO NOT apply any pressure to the eye . Never palpate the globe, check for induration, or perform tonometry (measuring intraocular pressure can cause immediate, irreversible extrusion of intraocular contents and permanent blindness).

DO NOT Instill Eye Drops : Avoid topical antibiotics, cycloplegics, or ointments (ointments cause toxic chemical endophthalmitis if introduced inside the eye).

Place a Rigid Eye Shield (Fox Shield) : Rest the metallic or plastic shield securely on the bony orbital margins (forehead and cheek). Never place an eye patch or gauze pad underneath the shield that can compress the globe.

Keep Patient Strictly NPO : Prepare for emergent operative microsurgical globe repair.

Prevent Valsalva / Spikes in IOP : Administer IV antiemetics (e.g., ondansetron 4 mg IV) immediately; nausea and vomiting cause massive venous spikes that extrude intraocular contents.

Systemic Antibiotic Prophylaxis : Administer broad-spectrum intravenous antibiotics (e.g., IV Vancomycin plus IV Ceftazidime or Ciprofloxacin) to prevent bacterial endophthalmitis. Update tetanus vaccination.

Immediate Ophthalmology Consultation : Direct transfer to the operating room for primary microsurgical closure.

Preseptal (Periorbital) vs Orbital (Postseptal) Cellulitis

The orbital septum is a thin, fibrous connective tissue sheet extending from the orbital periosteum to the tarsal plates of the eyelids, functioning as an anatomical barrier separating the superficial eyelid tissues from the deep orbital cavity.

Clinical Differentiation

Feature Preseptal (Periorbital) Cellulitis Orbital (Postseptal) Cellulitis

Anatomical Localization Confined strictly to soft tissues anterior to the orbital septum (eyelid skin and subcutaneous tissues) Infection involves structures posterior to the orbital septum within the bony orbit (orbital fat, extraocular muscles, optic nerve)

Etiology & Source Local skin trauma, insect bite, abrasion, scratch, chalazion, or hordeolum Contiguous extension of acute bacterial rhinosinusitis (especially ethmoid sinusitis via the thin, porous lamina papyracea ); dental infections, orbital trauma

Microbiology Staphylococcus aureus (including MRSA), Streptococcus pyogenes (Group A Strep) S. aureus (including MRSA), Streptococcus pneumoniae , Streptococcus anginosus group, anaerobes

Eyelid Edema & Erythema Marked swelling, warmth, and redness of the eyelid Marked eyelid swelling and violaceous erythema

Visual Acuity Completely Normal Decreased / Impaired visual acuity (compression of optic nerve)

Pupillary Light Reflex Completely Normal Relative Afferent Pupillary Defect (Marcus Gunn pupil) present if optic nerve is compromised

Extraocular Motility Full, painless extraocular movements Painful eye movements, restricted motility, ophthalmoplegia, and diplopia

Proptosis (Exophthalmos) ABSENT PRESENT (axial displacement of globe by inflamed orbital tissues/pus)
Conjunctival Chemosis Absent or minimal Marked conjunctival chemosis and injection

Systemic Toxicity Mild; patient is non-toxic, low-grade or no fever High fever, marked leukocytosis, lethargy, systemic toxicity

Diagnostic Imaging Clinical diagnosis; imaging not required if purely preseptal Urgent Contrast-Enhanced CT of the Orbits and Paranasal Sinuses (with thin axial and coronal cuts) to rule out subperiosteal abscess

Management Outpatient oral antibiotics (Amoxicillin-clavulanate or Cephalexin PLUS TMP-SMX or Clindamycin for MRSA); close 24-hour follow-up Immediate hospital admission ;; • IV broad-spectrum antibiotics (IV Vancomycin PLUS Ceftriaxone or Ampicillin-sulbactam);; • Emergent Ophthalmology & ENT consultation;; • Surgical drainage for subperiosteal abscess or visual decline