Ophthalmology is a crucial field of medicine dealing with the diagnosis and treatment of eye disorders. For medical students, understanding the various ophthalmic conditions, their causes, clinical presentations, and management strategies is essential for both academic success and practical application.
This document provides comprehensive notes on important ophthalmological topics, including Retinoblastoma, CRAO, CRVO, BRAO, BRVO, and Eales’ Disease, structured to aid in efficient exam preparation.
1. Retinoblastoma
Retinoblastoma is the most common primary intraocular malignancy in children, arising from the retinal neuroepithelium due to a mutation in the RB1 gene. Retinoblastoma is a kind of eye cancer that starts as a growth of cells in the retina.
Causes:
- Germline mutation (heritable, bilateral, younger age)
- Somatic mutation (non-heritable, unilateral, older age)
Signs and Symptoms:
- White or white spots in the pupil
- White glow in the eye in photos taken with a flash
- Crossed eyes or eyes that don't point in the same direction
- Double vision
- Eye pain and redness
- Poor vision
- Differing iris colors in each eye
- Leukocoria (white pupillary reflex)
- Strabismus
- Proptosis (if extraocular spread)
- Secondary glaucoma
Diagnosis:
- Clinical examination
- B-scan ultrasonography (calcifications, mass)
- MRI/CT scan (extraocular spread, calcifications)
- Genetic testing for RB1 mutations
Investigations:
- Fundoscopy: Elevated mass with chalky white areas
- Fluorescein angiography: Hyperfluorescent lesion
- Lumbar puncture & bone marrow biopsy (if metastasis suspected)
Treatment:
- Small tumors: Laser photocoagulation, cryotherapy
- Medium tumors: Chemotherapy (Vincristine, Etoposide, Carboplatin), local therapy
- Large tumors: Enucleation, external beam radiotherapy
- Metastatic: Systemic chemotherapy
Management:
- Lifelong follow-up for recurrence and second malignancies
- Genetic counseling for family members
2. Central Retinal Artery Occlusion (CRAO)
CRAO is an ophthalmic emergency caused by an occlusion of the central retinal artery, leading to sudden, painless vision loss.
Causes:
- Atherosclerosis
- Embolism (carotid artery disease, cardiac emboli)
- Giant cell arteritis
- Hypercoagulable states
- Vasculitis
Signs and Symptoms:
- Sudden, painless monocular vision loss
- Cherry red spot at the macula
- Retinal pallor
- “Boxcar segmentation” in retinal vessels
- Relative afferent pupillary defect (RAPD)
Diagnosis:
- Fundoscopy: Cherry red spot
- Fluorescein angiography: Delayed filling
- Optical coherence tomography (OCT): Inner retinal edema
- ESR, CRP (for GCA evaluation)
Investigations:
- Carotid Doppler
- Echocardiography (to rule out embolic source)
- Blood tests: Lipid profile, coagulation profile
Treatment:
Immediate treatment within 4 to 5 hours:
- Ocular massage
- Anterior chamber paracentesis
- Hyperbaric oxygen therapy
- IV acetazolamide
- Inhalation of carbogen (95% O2 + 5% CO2)
- If due to GCA: High-dose IV steroids (Methylprednisolone)
Management:
- Control risk factors (HTN {Hypertension}, DM, atherosclerosis)
- Antiplatelet therapy (Aspirin, Clopidogrel)
- Long-term follow-up
3. Central Retinal Vein Occlusion (CRVO)
CRVO is caused by a thrombotic occlusion of the central retinal vein leading to retinal hemorrhages and macular edema.
Causes:
- Hypertension, diabetes, hyperlipidemia
- Hypercoagulable states
- Glaucoma
- Vasculitis
Signs and Symptoms:
- Sudden, painless vision loss (mild to severe)
- “Blood and thunder” appearance (widespread retinal hemorrhages)
- Macular edema
- Dilated, tortuous retinal veins
- RAPD in ischemic CRVO
Diagnosis:
- Fundoscopy: Flame-shaped hemorrhages, disc edema
- Fluorescein angiography: Capillary non-perfusion
- OCT: Macular edema
- Blood tests: Coagulation workup
Treatment:
- Macular edema: Intravitreal Anti-VEGF (Ranibizumab, Aflibercept) or steroids (Triamcinolone)
- Neovascularization: Panretinal photocoagulation (PRP)
- Underlying cause management
Management:
- Monitor for neovascular glaucoma
- Control systemic conditions
- Antiplatelet therapy if indicated
4. Branch Retinal Artery Occlusion (BRAO)
BRAO is the occlusion of a branch retinal artery, leading to sectoral retinal ischemia.
Causes:
- Carotid embolism
- Cardiac embolism
- Hypercoagulability
Signs and Symptoms:
- Sudden, painless partial vision loss
- Sectoral retinal whitening
- Relative afferent pupillary defect (if severe)
Diagnosis:
- Fundoscopy: White, edematous retina in the affected area
- Fluorescein angiography: Delayed arterial filling
- OCT: Inner retinal atrophy
Investigations:
- Carotid Doppler
- Echocardiography
- Coagulation profile
Treatment:
- Similar to CRAO (ocular massage, paracentesis, carbogen inhalation)
- Antiplatelet therapy (Aspirin, Clopidogrel)
Management:
- Control risk factors
- Long-term follow-up
5. Branch Retinal Vein Occlusion (BRVO)
BRVO occurs due to occlusion of a branch retinal vein at an arteriovenous crossing, causing sectoral hemorrhages and macular edema.
Causes:
- Hypertension
- Diabetes
- Hyperlipidemia
Signs and Symptoms:
- Gradual, painless sectoral vision loss
- Retinal hemorrhages in a quadratic pattern
- Macular edema
Diagnosis:
- Fundoscopy: Flame-shaped hemorrhages in one quadrant
- Fluorescein angiography: Capillary non-perfusion
- OCT: Macular edema
Treatment:
- Macular edema: Anti-VEGF means Vascular Endothelial Growth Factor (Ranibizumab, Bevacizumab), intravitreal steroids
- Neovascularization: Laser photocoagulation
Management:
- Control systemic conditions
- Long-term monitoring
6. Eales' Disease
Eales' disease is an idiopathic, inflammatory occlusive vasculopathy affecting young adults, primarily in South Asia.
Causes:
Unknown, but associated with tuberculosis and hypersensitivity reactions
Signs and Symptoms:
- Recurrent vitreous hemorrhage
- Peripheral retinal vasculitis
- Neovascularization
- Floaters, blurred vision
Diagnosis:
- Fundoscopy: Perivascular sheathing, neovascularization
- Fluorescein angiography: Capillary non-perfusion, leakage
- Tuberculin skin test, QuantiFERON-TB Gold
Investigations:
- Chest X-ray (if TB suspected)
- Blood tests: CBC, ESR
Treatment:
- Corticosteroids: Periocular or systemic steroids
- Anti-tubercular therapy (if TB positive)
- Laser photocoagulation (for neovascularization)
- Vitrectomy (for persistent hemorrhage)
Management:
- Regular follow-up
- Avoidance of smoking, stress
- Monitor for recurrence