Important One-Liners in Ophthalmology

Embryology of Eye Structures

Surface Ectoderm 

• Lens 
• Conjunctival, Corneal epithelium 
• Lacrimal glands 

Mesoderm

• Extraocular muscles 
• Sclera 
• Iris 
• Choroid

Neural Ectoderm

• Smooth muscles of iris 
• Iris epithelium & Ciliary epithelium 
• Retina 
• Optic nerve

Neural Crest 

• Corneal stroma, keratocytes, Corneal endothelium 
• Trabecular meshwork endothelium 
• Melanocytes 
• Ciliary muscles 
• Lenticular opacity, which diminishes the vision most, is 'Posterior subcapsular cataract because it is near the nodal point of the eye. 
• Drugs causing posterior subcapsular cataract
  • Busulphan 
  • Steroids 
  • Chloroquine 
• Named cataracts: conditions
  • Oil drop cataract—galactosemia 
  • Sunflower cataract - Wilson's disease 
  • Christmas tree cataract - myotonic dystrophy 
  • Snowflake cataract: diabetes mellitus 
  • Rosette cataract—trauma 
• Normal IOP = 10-21 mmHg; Peaks in the early morning Because steroid level is higher in the morning
  • Normal diurnal variation of IOP is equal to or less than 5 mmHg. 
• Layers of retina
  • Retinal pigment epithelium 
  • Layers of rods and cones 
  • External limiting membrane 
  • Outer nuclear layer 
  • Outer plexiform layer 
  • Inner nuclear layer 
  • Inner plexiform layer
  • Ganglion cell layer 
  • Nerve fibre layer 
  • Internal limiting membrane

Also read: Pathology One-Liners for Medical Students

Extraocular Muscles

• The angle subtended by any letter on the Snellen's chart at the nodal point of the patient is 5 min 
• M/c etiological factor for acute and chronic dacryocystitis → Staphylococcus aureus 
• Sequale of acute dacryocystitis treated by DCR → Lacrimal fistula 
• Reflex tear production starts around 6 weeks 
• Chalazion is a chronic lipogeanulomatous inflammation of the meibomian gland. 
• M/c cause of recurrent chalazion → Uncorrected mild refractive error. 
• Treatment of chalazion is Incision & Curettage 
• Causes of Acute Red eye
  • Acute conjunctivitis 
  • Acute iridocyclitis 
  • Acute Angle-closure Glaucoma 
  • Corneal abrasion/infection
• Treatment and prevention of trachoma
  • Treat with a single oral dose of Azithromycin (or) Tetracycline eye ointment for 6 weeks 
  • SAFE strategy by WHO for controlling Trachoma
    • S – Surgery for trichiasis 
    • A – Antibiotics 
    • F – Facial hygiene 
    • E – Environmental hygiene  
• Signs of Graft rejection in patients for keratoplasty 

1. Krachmer spots: Subepithelial Graft rejection 
2. Khodadoust line: Endothelial Graft rejection 
3. Kaye's dot: Epithelial Graft rejection 

• The minimum number of endothelial cells in a corneal graft should be at least 2000 cells/mm²
• P.E.R.F.E.C.T surgery is related to pterygium; it stands for pterygium Extended Removal followed by extended conjunctival transplant 
• Pterygium
  • Connective tissue disorder 
  • Etiology: UV-B 
  • M/c located nasally

Also read: Important One-Liners in Public Health & Community Medicine (PSM)

Glass Rod is Used to Differentiate between Pterygium and Pseudopterygium 

• If glass rod passes through → pseudo pterygium 
• If it does not pass through → Pterygium 
• Hypopyon
  • Inverse hypopyon/hyperleon is a complication of RD surgery 
  • Silicon gel which is a vitreous substrate, leaks into the anterior chamber during RD surgery 
  • Recurrent Hypopyon → Behcet's disease 
  • Pseudohypopyon → Retinoblastoma 
• M/c cause of Bacterial keratitis (Worldwide) → Staphylococcus Aureus
  • India → Staphylococcus epidermidis 
• Keyhole shaped scotoma is a feature of lateral geniculate body lesion 
• Keyhole vision is a feature of occipital lobe lesion 
• Weber's syndrome is 3rd nerve palsy with C/L hemiplegia
• Benedicts syndrome is 3rd nerve palsy with C/L hemiataxia and tremors. 
• Millard Gubler syndrome is 6th nerve palsy with C/L hemiplegia 
• Foster – Kennedy syndrome is I/L optic atrophy + c/L papilla
  • Seen in
    • Frontal lobe tumors 
    • Olfactory lobe tumor 
• Oil droplet cataract - Galactosemia 
• Oil droplet reflex - Keratoconus 
• Oil globular reflex - Anterior lenticonus 
• “A” wave in ERG is due to activity of Rods 
• “B” wave in ERG is due to Bipolar cells and muller cells 
• “C” wave in ERG is due to RPE
• Ocular features of Rubella
  • Microphthalmos 
  • Rubella keratitis 
  • Angle anomaly 
  • Cataract (m/c) 
  • Salt and pepper fundus 
• Salt & Pepper fundus is seen in
  • Rubella 
  • Syphilis 
  • Myotonic dystrophy 
• Direction of subluxation in Marfan's syndrome → Superotemporal 
• Direction of subluxation in Homocystinuria → inferonasal 
• Causes of pulsating proptosis
  • M/c
    • Carotico - cavernous fistula 
    • NF – 1 
    • Fracture of roof of orbita
• Intraocular lenses
  • Non-foldable IOL (Rigid): Made of PMMA 
  • Foldable IOL:
    • Silicone IOL 
    • Acrylic IOL 
    • Hydrophobic 
    • Hydrophilic 
    • Hydrogel IoL 
  • Multifocal IOLs
    • Allows clear vision for both distance and near 
• 1st order neurons: bipolar cells 
• 2nd order neurons - Ganglion cells/ optic nerve 
• 3rd order neurons - Lateral geniculate body 
• M/c presentation of retinoblastoma is leukocoria 
• 2nd m/c presentation is strabismus 
• M/c made of spread is through optic nerve 
• Wave length of Femto laser is 1054 nm 
• Wave length of Excimer laser is 193 nm 
• Wave length of NDYAG laser is 1064 mm 
• Wave length Argon is 514 nm 
• Most important factor to keep the cornea in dehydrated state is endothelial pump dysfunction 
• Vitamin deficiencies and ocular findings
  • Vit A deficiency → Xerophthalmia 
  • Vit B₂ deficiency → circumcorneal neovascularisation 
  • Vit B₆ deficiency → Gyrate atrophy 
  • Vit B₁₂ deficiency → Optic neuritis 
• Features of Blunt trauma
  • Rosette shaped cataract 
  • Vossious Ring 
  • Berlin's edema 
• Headlight in fog is a feature of Toxoplasmas

Also read: The Lacrimal Drainage System

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