Kanski's Clinical Ophthalmology - How Long to Finish and Retain It

The Book at a Glance

Time Estimates - By Study Goal

Realistic Schedule (3-Month Plan, Recommended)

• Weeks 1-2: Ch. 1-4 (Examination, Eyelids, Lacrimal, Orbit)
• Weeks 3-4: Ch. 5-10 (Dry Eye, Conjunctiva, Cornea, Lens)

• Weeks 1-2: Ch. 11-12 (Glaucoma, Uveitis - these are the two densest chapters)
• Weeks 3-4: Ch. 13-17 (Retinal vascular, Macula, Inherited, Detachment)

• Week 1-2: Ch. 18-22 (Strabismus, Neuro-ophthalmology, Tumours, Trauma)
• Weeks 3-4: Full revision pass, Anki deck review, MCQ practice

Key Tips for Retention

1. Study images first. Kanski is built around clinical photographs - before reading a section, look at all the images in it. Your brain encodes the pattern visually, then the text fills in the mechanism.
2. Prioritize the heavy chapters. Glaucoma (Ch. 11), Uveitis (Ch. 12), Neuro-ophthalmology (Ch. 19), and Retinal Vascular Disease (Ch. 13) together make up ~35% of the book. Budget extra time here.
3. Use spaced repetition. After finishing each chapter, create 20-30 Anki cards (key findings, eponyms, management stepladders). Review the deck daily for 10 minutes. This alone roughly doubles long-term retention compared to re-reading.
4. Don't re-read passively. After your first pass, testing yourself (covering text, recalling findings from images) is far more effective than reading again.
5. Pair with clinical exposure. Seeing real patients or case photos while reading the corresponding chapter locks in memory far faster than text alone.

Bottom Line

Kanski Cornea Chapter - Complete Study Guide

Complete Topic Map (Chapter 7)

Section A - Foundations (Study First)

1. Anatomy and Physiology - dimensions, 5-layer structure (epithelium, Bowman, stroma, Descemet, endothelium)
2. Signs of Corneal Disease
   • Superficial signs (epithelial staining patterns, filaments, pannus)
   • Deep signs (KPs, stromal edema, neovascularization, scarring)
   • Documentation (slit-lamp grading)
3. Specular Microscopy - endothelial cell count, polymegethism, pleomorphism
4. Corneal Topography - Placido disc, elevation maps
5. Principles of Treatment - infection control, promoting epithelial healing

Section B - Infections (Core Clinical)

1. Bacterial Keratitis - pathogens, risk factors, ulcer morphology, Gram stain, fortified antibiotics, treatment failure
2. Fungal Keratitis - filamentous vs. Candida, feathery infiltrate, natamycin/voriconazole
3. Herpes Simplex Keratitis (HSK) - primary vs. recurrent, 5 types:
   • Epithelial (dendritic/geographic) - treat with antivirals
   • Disciform keratitis - stromal immune reaction
   • Necrotizing stromal keratitis
   • Neurotrophic keratopathy
   • Iridocyclitis; prophylaxis with long-term acyclovir
4. Herpes Zoster Ophthalmicus - Hutchinson's sign, acute vs. chronic eye disease, post-herpetic neuralgia
5. Interstitial Keratitis - syphilitic IK (salmon patch, ghost vessels), Cogan syndrome
6. Protozoan Keratitis (Acanthamoeba) - contact lens risk, ring infiltrate, PHMB/polyhexamethylene biguanide
7. Helminthic Keratitis - onchocerciasis (river blindness)
8. Microsporidial Keratitis

Section C - Inflammatory & Immune

1. Bacterial Hypersensitivity Keratitis
   • Marginal keratitis - peripheral ulcer, clear zone from limbus
   • Phlyctenulosis - nodular limbal/corneal lesion
2. Rosacea Keratitis - inferior corneal vascularization, meibomian gland dysfunction link
3. Peripheral Corneal Ulceration/Thinning
   • Mooren ulcer - idiopathic, painful, central guttering
   • Peripheral ulcerative keratitis (PUK) - associated with systemic vasculitis (RA, Wegener's)

Section D - Ectasias

1. Keratoconus - scissors reflex, Munson sign, Fleischer ring, Vogt striae, Rizzuti sign; corneal cross-linking (CXL)
2. Pellucid Marginal Degeneration
3. Keratoglobus
4. Post-LASIK ectasia

Section E - Dystrophies (genetically determined, bilateral, symmetric)

1. Epithelial and Subepithelial:
   • Meesmann dystrophy
   • Epithelial basement membrane dystrophy (EBMD / map-dot-fingerprint)
   • Reis-Bucklers dystrophy
2. Stromal:
   • Granular dystrophy (breadcrumb opacities, Masson trichrome stain)
   • Lattice dystrophy (branching refractile lines, amyloid, Congo red)
   • Macular dystrophy (diffuse clouding, alcian blue, keratan sulfate)
   • Schnyder crystalline dystrophy
3. Endothelial:
   • Fuchs endothelial dystrophy (cornea guttata, Hassal-Henle bodies)
   • Posterior polymorphous dystrophy (PPMD)
   • Congenital hereditary endothelial dystrophy (CHED)

Section F - Degenerations

1. Arcus senilis
2. Pterygium - fibrovascular ingrowth, Stocker line
3. Calcific band keratopathy
4. Terrien marginal degeneration
5. Recurrent corneal epithelial erosion

Section G - Metabolic & Miscellaneous

1. Metabolic keratopathies - Wilson disease (Kayser-Fleischer ring), cystinosis, tyrosinemia
2. Neurotrophic keratopathy - trigeminal nerve damage, Mackie staging
3. Contact lens-related disease - GPC, CLPU, CLARE, pseudomonas risk
4. Congenital anomalies - microcornea, megalocornea, Peters anomaly, sclerocornea

Study Schedule (2-Week Focused Posting Plan)

High-Yield Facts to Memorize First

• Dendritic ulcer = HSV epithelial keratitis. Terminal bulbs. Treat: acyclovir 3% ointment 5x/day. Never give steroids alone.
• Ring infiltrate = Acanthamoeba until proven otherwise. Contact lens + water exposure history.
• Feathery edges + satellite lesions = Fungal keratitis. Post-trauma with vegetable matter.
• Clear zone between ulcer and limbus = Marginal keratitis (staph hypersensitivity). Steroids + antibiotics.
• No clear zone + melting = Mooren or PUK - check ANA, ANCA, RF.
• Munson sign + scissors reflex = Keratoconus. Fleischer ring (iron) + Vogt striae.
• Cornea guttata + corneal edema = Fuchs dystrophy. Worse in morning.
• KF ring = Wilson disease (copper). Slit-lamp: golden-brown at Descemet periphery.
• Hutchinson's sign (tip of nose involved) = 76% risk of ocular involvement in HZO.
• Breadcrumbs = Granular (TGFBI, AD), branching lines = Lattice (amyloid), diffuse haze = Macular (AR, worst vision).

How to Use the Book in the Department

1. Before OPD: Skim the images/figures of the day's topic - takes 10 min.
2. After OPD: Read the full section for conditions you actually saw that day. Active recall is strongest right after seeing a patient.
3. Evening: Make 5-10 Anki cards per session (signs, investigations, treatment steps).
4. Weekend: Review the whole week's cards + re-read one section from scratch.

What's Inside (1.1 MB, 97 slides)

• Front (navy): category tag + question number + the question
• Back (dark blue): structured answer with a gold PEARL box at the bottom for mnemonics/clinical tips

14 Categories Covered

How to Use

• Open in PowerPoint and go through slide by slide (question → answer)
• Use Presenter View to show only the front card on screen and keep the answer hidden
• You can also print 4 slides/page (2 fronts + 2 backs) as paper flashcards
• Work through 10 cards/day in the morning before OPD - 5 days to complete the full deck

Kanski Cornea - Session 1: Anatomy & Signs of Corneal Disease

PART 1: ANATOMY

The Cornea at a Glance

• Horizontal diameter: 12 mm, Vertical: 11.5 mm
• Central thickness: ~540 µm (range 490-590 µm)
• Peripheral thickness: ~700 µm
• Central corneal thickness (CCT) is a key determinant of IOP readings - thin cornea underestimates IOP on applanation tonometry

The 5 Layers - Deep Dive

Fig. 7.1 - Anatomy of the cornea (Kanski 10th ed.)

Layer 1: Epithelium

• Limbal stem cell deficiency (LSCD) → "conjunctivalization" of the cornea: vascularization + goblet cells appear on corneal surface
• Causes of LSCD: chemical burns, Stevens-Johnson syndrome, aniridia, repeated surgeries
• Treatment: limbal stem cell transplantation (autograft or allograft)

Clinical tip: Superficial cells are shed every few days into the tear film. The entire epithelium turns over every 7-10 days. This is why superficial defects heal quickly but recurrent erosion is about a deeper problem - faulty hemidesmosome anchoring.

Layer 2: Bowman Layer

• Acellular, formed from randomly arranged collagen fibres (unlike the regular lamellae of the stroma)
• 8-12 µm thick
• Does NOT regenerate - any significant injury to Bowman leaves a permanent scar
• This is clinically relevant: PTK (phototherapeutic keratectomy) ablates Bowman deliberately in band keratopathy/EBMD, but the resulting surface heals over with epithelium, not new Bowman

Layer 3: Stroma

• Makes up 90% of corneal thickness (~480 µm)
• Composed of ~200 regular, parallel lamellar sheets of collagen fibrils
• The spacing between fibrils is maintained by proteoglycan ground substance (primarily keratan sulphate and chondroitin sulphate)
• Scattered keratocytes (modified fibroblasts) maintain the extracellular matrix
• The regularity of collagen spacing = optical clarity. Any swelling, scar, or infiltrate disrupts this arrangement

Mechanism of corneal oedema: When stroma swells, the collagen fibril spacing increases beyond the critical ~60 nm needed for destructive interference of scattered light → you see clouding.

Layer 4: Descemet Membrane

• Anterior banded zone - laid down in utero, 3 µm thick
• Posterior non-banded zone - laid down throughout life by the endothelium, thickens with age (reaches ~10 µm in adults)

• Horizontal/oblique = congenital glaucoma (buphthalmos)
• Vertical = birth forceps trauma

Layer 5: Endothelium

A note on Dua's Layer: A 6th layer between the posterior stroma and Descemet has been proposed (15 µm thick, acellular). Its clinical relevance is in DMEK surgery and big-bubble DALK technique. Kanski acknowledges it but notes some authorities consider it posterior stroma.

Innervation - Why Corneal Pain is So Severe

1. Subepithelial plexus - just below epithelium, dense
2. Deeper stromal plexus

PART 2: SIGNS OF CORNEAL DISEASE

SUPERFICIAL SIGNS

Fig. 7.2 - Superficial corneal lesions (Kanski 10th ed.)

1. Punctate Epithelial Erosions (PEE) - Panel A

PEE vs PEK: PEE = epithelial defects (stain with fluorescein). PEK (punctate epithelial keratitis) = swollen/opalescent cells (stain better with rose bengal, variably with fluorescein).

2. Filaments - Panel B

• Dry eye (by far the most common)
• Superior limbic keratoconjunctivitis (SLK)
• Neurotrophic keratopathy
• Long-term ocular patching

3. Subepithelial Infiltrates - Panel C

4. Epithelial Oedema + Bullae - Panel D

5. Superficial Neovascularization - Panel E

6. Pannus - Panel F

DEEP SIGNS

The PEDAL Mnemonic - Infective vs. Sterile Infiltrate

PEDAL = Pain, Epithelial defect, Discharge, Anterior chamber reaction, Location. Use this at every corneal infiltrate you see in OPD.

Other Deep Signs

HOW TO DOCUMENT CORNEAL LESIONS

THE SEIDEL TEST

• Apply 1-2% fluorescein to the eye
• Use cobalt blue filter on slit-lamp
• Positive: colour changes from dark orange → bright yellow-green at one spot
• Means: aqueous is leaking through a wound or perforation at that site (diluting the concentrated dye)

Summary - What You Now Know

CORNEA = Protection + Optics
5 Layers: Epithelium > Bowman > Stroma > Descemet > Endothelium
Key facts: Bowman & stroma cannot regenerate. Descemet & epithelium can.
Endothelium: pump cells, cannot regenerate, <500/mm² → oedema.
Stem cells: limbus. Lose them → conjunctivalization.

Signs by location:
Superior PEE → vernal/SLK/chlamydia
Inferior PEE → blepharitis/lagophthalmos/toxic drops
Interpalpebral → dry eye
Central → contact lenses

PEDAL = how to tell infective from sterile infiltrate
Seidel test = aqueous leak detection
Document all lesions with size + colour-coded diagram

Signs of Corneal Disease - Taught Simply

SUPERFICIAL SIGNS (Epithelium layer)

Panel A - Punctate Epithelial Erosions (PEE)

• Dots at the top (superior) → something is rubbing the upper cornea → vernal disease (giant papillae under upper lid), trachoma, SLK
• Dots in the middle exposed zone (interpalpebral) → the exposed surface is drying out → dry eye, UV damage (welding, snow)
• Dots at the bottom (inferior) → lower lid problem → blepharitis, inward-turning eyelashes (trichiasis), toxic eye drops (BAK preservative)
• Dots scattered everywhere (diffuse) → viral conjunctivitis or toxic drops affecting the whole surface
• Dots only in the centre → contact lens sitting on the cornea centre too long → contact lens wear

Panel B - Filaments

Panel C - Subepithelial Infiltrates

Panel D - Epithelial Oedema and Bullae

Panel E - Superficial Neovascularisation

Panel F - Pannus

DEEP SIGNS (Stroma, Descemet, Endothelium)

(Fig. 7.3 from Kanski - this is a stromal infiltrate / ulceration image)

Infiltrate (Deep)

• Infective → needs aggressive antibiotics/antivirals immediately
• Sterile → needs steroids (giving antibiotics alone won't help; giving steroids on an infection will make it catastrophically worse)

• Infective = usually one lesion, one eye
• Sterile = often multiple lesions, sometimes both eyes

Ulcer

Melting

Deep Vascularisation

Descemet Folds (Striate Keratopathy)

Descemetocele

Haab Striae

• Horizontal striae → the eyeball was enlarged (buphthalmos from congenital glaucoma) → Descemet was stretched sideways → horizontal breaks
• Vertical striae → forceps pressed on the eye during birth → vertical breaks

THE SEIDEL TEST - a must-know practical skill

1. Put a drop of 2% fluorescein on the eye
2. Put cobalt blue light on the slit-lamp
3. The dye on the surface looks dark orange
4. If aqueous is leaking: the leak dilutes the concentrated dye → you see a bright yellow-green stream coming from one spot

QUICK SUMMARY - Signs and Their Meaning

• Correct name: Punctate Epithelial Erosions (PEE)
• Correct causes: chronic blepharitis, lagophthalmos, eye drop toxicity, self-induced ✓

• "Ulcerative keratopathy" is not in the inferior PEE list - you may be mixing it with something else. The ones you missed are aberrant eyelashes (trichiasis/distichiasis) and entropion (inward-turning lid). Both physically rub the inferior cornea.

• (a) What is this sign called?
• (b) What layer is failing to cause this?
• (c) What is the most likely diagnosis?

• Cycloplegic (cyclopentolate) - to relax ciliary spasm and relieve pain
• Lubricants / preservative-free drops
• Bandage contact lens - reduces pain from blinking over exposed nerve endings
• Oral analgesics - the pain can be severe
• It heals on its own within 24-48 hours because the epithelium regenerates quickly

No infiltrate + no discharge + no AC reaction = sterile = no antibiotics

• Single white-grey opacity, 3×3 mm, central cornea
• Large epithelial defect overlying it
• Thick purulent discharge
• Hypopyon 1.5 mm
• Patient reports severe pain
• One eye only

Corneal scraping for microbiological investigations - send for Gram stain and culture.

Scrape first, treat second - always, for any significant corneal ulcer.

• Central ulcer >2 mm
• No prior antibiotic use
• Atypical appearance
• Treatment failure after 48-72 hours
• Immunocompromised patient

• Antibiotics - No ✅ you got this right
• Acyclovir - ❌ Wrong drug. Acyclovir works against Herpes simplex / Herpes zoster. Adenovirus is a completely different virus - acyclovir has no effect on adenovirus. Do not give it here.
• Lubricants ✅ correct for mild symptoms
• Correct treatment for symptomatic subepithelial infiltrates: Topical steroids (e.g. prednisolone 0.5% or fluorometholone) - they suppress the immune reaction and clear the infiltrates. BUT they recur when you taper the steroid, so you have to wean very slowly.

Subepithelial infiltrates after adenovirus = topical steroids, not antivirals, not antibiotics. Acyclovir = HSV/HZV only.

Your question: Adenovirus vs HSV when patient presents late?

• Normal sensation → adenovirus
• Reduced sensation → HSV has damaged the trigeminal nerve endings

Q6 - Seidel Test

• Risk of infection entering the eye → endophthalmitis
• Risk of iris/vitreous prolapse
• Do NOT patch tightly, do NOT put any drops with preservatives
• Apply a rigid shield (not a pad) to protect the eye
• Refer urgently to theatre for primary surgical repair
• Give IV antibiotics prophylactically

• Admit the patient - do not send home
• Stop all preserved drops immediately (toxic to the already-fragile surface)
• Bandage contact lens or cyanoacrylate glue (tissue adhesive) as a temporising measure
• Urgent penetrating keratoplasty or tectonic graft to restore structural integrity
• Treat the underlying cause (infection, autoimmune)

Final Session Score

• Small white opacity at the 3 o'clock position, peripheral cornea
• A clear gap of about 1-2 mm between the opacity and the limbus
• Mild redness
• Minimal pain
• Both eyes affected
• Has crusty eyelids in the morning

• Crescent-shaped ulcer at the peripheral cornea
• NO clear gap - the ulcer runs right up to the limbus
• Severe pain
• Progressive - getting worse each day
• Slit-lamp shows the cornea is thinning and "melting"
• Bloods show positive RF and anti-CCP

• Marginal keratitis = clear zone present between ulcer and limbus
• PUK / Mooren = no clear zone - ulcer reaches right to the limbus

Clear zone = Marginal keratitis (sterile, treat with steroid + treat blepharitis) No clear zone + melting = PUK (autoimmune, screen for RA/vasculitis, needs systemic immunosuppression)

• Patient X: You suspect dry eye with filaments
• Patient Y: You suspect a corneal abrasion (epithelial defect)
• Patient Z: You suspect a herpetic dendrite - you want to see the devitalized cells at the edges clearly

• Fluorescein → stains the ulcer base (the actual defect) green
• Rose bengal → stains the terminal bulbs and devitalized cells at the edges pink - this is what makes the dendrite look like a classic branching pattern with bulbs at the tips

• Blurry vision
• The cornea looks hazy and slightly cloudy
• On slit-lamp you see fine parallel wavy lines running across the deep cornea
• No epithelial defect, no infiltrate, no discharge

• Topical steroids (prednisolone 1%) - reduce post-operative inflammation
• Hypertonic saline drops (5% NaCl) - draws water out of the oedematous cornea osmotically
• Monitor - mild post-op DM folds often resolve within days as the endothelium recovers
• If not improving → check specular microscopy → consider DMEK if endothelial count critically low

Session 2 Complete - Final Tally

Overall Score (Both Sessions)

• Strong: sign identification, emergency recognition, clinical reasoning
• Needs work: specific drug names, eponyms/test names, clear zone terminology

The Core Principle

A healthy cell with an intact membrane does NOT let dye in. A dead, dying, or membrane-damaged cell DOES.

Fluorescein - "The Defect Detector"

• Epithelial defects (abrasions, ulcers)
• PEE (tiny inter-cell gaps)
• The base of a dendritic ulcer
• Aqueous leaks (Seidel test - fluorescein is diluted by aqueous → colour shift)

• Dead cells with intact membranes
• Mucus
• Devitalized but still-attached cells

Rose Bengal - "The Dead Cell Detector"

Healthy cells are protected from rose bengal staining by the tear film mucin layer coating their surface. When cells are devitalized, they lose this mucin protection → rose bengal penetrates and stains them red.

• Devitalized epithelial cells (dry eye, exposure, toxicity)
• Mucus filaments (dry eye filaments)
• Terminal bulbs of HSV dendrite (the bulb cells are devitalized virus-infected cells)
• Edges of a dendritic ulcer (surrounding devitalized cells)

Lissamine Green - "The Gentle Rose Bengal"

Side by Side Comparison

Why Specific Stains for Specific Diseases

• The floor of the ulcer = epithelial defect = Fluorescein stains it green
• The terminal bulbs and edges = devitalized virus-infected cells still sitting there = Rose bengal stains them red
• Using both together gives you the full picture of the dendrite - floor + outline

One Sentence Summary for Each

• Fluorescein = shows you where cells are missing (gaps, defects, leaks)
• Rose bengal = shows you where cells are dead but still present
• Lissamine green = same as rose bengal, better tolerated

GROUP 1: CLINICAL STAINS (Used on the Patient)

1. Fluorescein

• Corneal abrasions, ulcers
• PEE in dry eye
• Dendrite floor in HSV
• Seidel test (aqueous leak)
• Applanation tonometry (mixed with anaesthetic in Minims)
• Contact lens fitting (fluorescein pattern)
• Fundus fluorescein angiography (IV form - different use)

2. Rose Bengal

• Dry eye severity (van Bijsterveld score)
• Filaments
• HSV dendrite edges + terminal bulbs
• Sicca syndrome assessment (Sjogren's) Problem: Stings significantly on instillation

3. Lissamine Green

4. Indocyanine Green (ICG)

• ICG angiography - for choroidal neovascularisation (polypoidal choroidal vasculopathy, occult CNV)
• Where fluorescein angiography is inadequate (blocked by haemorrhage, RPE) Note: Can cause anaphylaxis in iodine-allergic patients

5. Trypan Blue

• Cataract surgery - stains the anterior lens capsule to make it visible during capsulorhexis (especially useful in mature/white cataracts where the red reflex is absent)
• DMEK/DSAEK surgery - stains the donor graft to help orientation
• Vitreoretinal surgery - stains epiretinal membranes

6. Brilliant Blue G

• Vitreoretinal surgery - ILM peeling for macular hole, epiretinal membrane
• Visualizes the thin transparent ILM that is otherwise invisible

7. Triamcinolone Acetonide (off-label stain)

• Vitreoretinal surgery - stains vitreous white, making it visible during vitrectomy
• Helps ensure complete vitreous removal

GROUP 2: LABORATORY STAINS (Corneal Scraping / Histology)

For Microbiology (Corneal Scraping)

For Histopathology (Tissue / Biopsy)

The Three Corneal Dystrophies - Stain Summary (High Yield)

Quick Summary Table

Stains in Ophthalmology - With Clinical Images

CLINICAL STAINS (Used on the Patient)

1. Fluorescein - "Shows gaps/defects"

• Panel A = Fluorescein showing PEE (dry eye) - tiny green dots on cobalt blue background
• Panel D = Fluorescein showing bullous keratopathy - the large green pool is where a bulla has ruptured, leaving an epithelial defect

2. Rose Bengal - "Shows dead cells + mucus"

LABORATORY / HISTOLOGY STAINS

3. Masson Trichrome - "Granular dystrophy"

4. Congo Red - "Lattice dystrophy (Amyloid)"

"Histology showing green birefringence of amyloid when viewed through polarised light"

5. Alcian Blue / PAS - "Macular dystrophy (Keratan sulphate/GAG)"

THE 3 DYSTROPHY STAINS SIDE BY SIDE

SURGICAL STAINS

6. Trypan Blue - "Cataract surgery / DMEK"

QUICK VISUAL SUMMARY

• Fluorescein - shows the epithelial defects (PEE)
• Rose bengal / Lissamine green - shows the devitalized cells AND the mucus filaments

• Fluorescein → tiny bright yellow-green dots (PEE) scattered across the exposed cornea under cobalt blue light
• Rose bengal / Lissamine green → pink/red staining of devitalized cells on cornea AND conjunctiva; if filaments are present, they stain brightly as red thread-like strands

• See the full extent of the ulcer floor
• See the terminal bulbs and devitalized edges clearly