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Here are comprehensive answers to all questions from your ophthalmology exam paper (ASMC/ABVMU), sourced primarily from Kanski's Clinical Ophthalmology, 10th Edition.

PART B - OPHTHALMOLOGY EXAM ANSWERS

LONG QUESTION 1 (20 marks)

Case: 47-year-old male, 2 weeks - blurring, pain, photophobia, eyelid swelling, watering left eye. Slit lamp: circumciliary congestion, AC reaction, mid-dilated pupil, posterior synechiae.

(a) Differential & Probable Diagnosis (2 marks)

Probable diagnosis: Acute Anterior Uveitis (Iridocyclitis)
Differentials to consider:
ConditionKey distinguishing feature
Acute Anterior UveitisPosterior synechiae, AC cells/flare, circumciliary congestion - most likely
Acute Angle-Closure GlaucomaMid-dilated fixed pupil, very high IOP, corneal haze, but NO posterior synechiae
Acute Bacterial ConjunctivitisMucopurulent discharge, no AC reaction, no synechiae
KeratitisCorneal opacity, staining, no posterior synechiae
The combination of posterior synechiae + AC reaction + circumciliary congestion + mid-dilated pupil is pathognomonic of iridocyclitis/anterior uveitis.

(b) Define and Classify Uveitis (5 marks)

Definition: Uveitis is inflammation of the uveal tract (iris, ciliary body, and choroid), the vascular middle coat of the eye.
Classification:
1. By Anatomical Location (SUN Working Group):
  • Anterior uveitis - iris/anterior ciliary body (iritis, iridocyclitis) - MOST COMMON
  • Intermediate uveitis - vitreous, pars plana, peripheral retina (pars planitis)
  • Posterior uveitis - choroid/retina posterior to vitreous (choroiditis, chorioretinitis)
  • Panuveitis - all segments involved
2. By Onset/Course:
  • Acute - sudden onset, limited duration (<3 months)
  • Chronic - persistent >3 months, often insidious onset
  • Recurrent - repeated episodes with disease-free intervals
3. By Pathology:
  • Granulomatous - mutton-fat KP, Koeppe/Busacca nodules; causes: sarcoidosis, TB, syphilis, VKH
  • Non-granulomatous - fine stellate KP; causes: HLA-B27, trauma, JIA

(c) Signs & Symptoms of Anterior Uveitis (5 marks)

Symptoms:
  • Rapid onset unilateral pain (deep, aching)
  • Photophobia (ciliary spasm)
  • Blurring of vision (cells/flare in AC, miotic pupil)
  • Lacrimation/watering
  • Redness (circumciliary/ciliary flush)
Signs (Slit lamp):
External:
  • Circumciliary congestion (ciliary/limbal flush) - violaceous redness at limbus
  • Lid edema
Anterior Chamber:
  • Cells in AC (graded 0.5+ to 4+)
  • Flare (protein exudation - Tyndall effect)
  • Hypopyon (sterile pus layer in severe cases)
  • Fibrinous exudate in severe inflammation
Cornea:
  • Keratic precipitates (KP) on inferior corneal endothelium (Arlt's triangle)
  • Fine/stellate (non-granulomatous) or mutton-fat (granulomatous)
Iris:
  • Posterior synechiae (adhesions between iris and lens) - present in THIS case
  • Anterior synechiae (iris to cornea)
  • Rubeosis iridis (in chronic cases)
  • Iris nodules (Koeppe - pupil margin; Busacca - iris stroma)
Pupil:
  • Mid-dilated (due to posterior synechiae preventing constriction)
  • Irregular shape due to synechiae
  • Seclusio pupillae (360° synechiae) → iris bombé
Lens:
  • Anterior subcapsular opacities (stellate cataract)
IOP: Usually low/normal (ciliary shutdown), rarely raised

(d) Investigations & Treatment (5 marks)

Investigations:
For the eye:
  • Slit lamp biomicroscopy (grading cells/flare)
  • IOP measurement
  • Dilated fundal examination (rule out posterior involvement)
Systemic workup (first episode/bilateral/atypical):
  • HLA-B27 typing
  • CXR (sarcoidosis, TB)
  • Mantoux/Quantiferon-TB Gold (TB)
  • FBC, ESR, CRP
  • VDRL/TPHA (syphilis)
  • ANA, RF (JIA, connective tissue disease)
  • ACE, serum lysozyme (sarcoidosis)
  • ANCA (vasculitis)
  • Urine microscopy (tubulointerstitial nephritis)
Treatment:
1. Topical Corticosteroids (mainstay):
  • Prednisolone acetate 1% or dexamethasone 0.1%
  • Hourly initially, then taper as inflammation subsides
2. Cycloplegics/Mydriatics (to prevent/break synechiae & relieve ciliary spasm):
  • Atropine 1% (long-acting, also breaks posterior synechiae)
  • Cyclopentolate 1% (shorter acting)
  • Homatropine 2% (intermediate)
3. Sub-Tenon's/Periocular Steroids:
  • Triamcinolone acetonide 40 mg - for non-infectious severe cases
4. Systemic Steroids:
  • For severe bilateral disease or when topical therapy insufficient
5. Immunosuppressives (for chronic/recurrent cases):
  • Methotrexate, azathioprine, mycophenolate mofetil
  • Biologics (adalimumab, infliximab) for refractory cases
6. Treat underlying cause (e.g., anti-TB, anti-syphilitic therapy)

(e) Complications (3 marks)

Anterior segment complications:
  • Posterior synechiae → irregular pupil, seclusio pupillae → iris bombé
  • Complicated cataract (anterior/posterior subcapsular opacity - stellate pattern)
  • Band keratopathy (calcium deposits in Bowman's layer - chronic, especially JIA)
  • Corneal decompensation (endothelial damage from chronic inflammation)
IOP-related complications:
  • Secondary glaucoma (open-angle from trabecular inflammation/scarring; angle-closure from iris bombé or peripheral anterior synechiae)
Posterior segment complications:
  • Cystoid macular edema (CME) - most common cause of visual loss
  • Optic disc edema/atrophy
  • Epiretinal membrane
  • Phthisis bulbi (end-stage, shrunken hypotonic eye)
  • Retinal detachment (tractional or rhegmatogenous)

SHORT QUESTIONS (6×5 = 30 marks)

Q2. Stages of Maturation of Senile (Age-Related) Cataract (5 marks)

Senile cataract is the most common form; the lens nucleus progressively hardens and the cortex becomes opaque. The stages apply primarily to cortical and nuclear types.
StageAppearanceFeatures
1. Immature (Incipient)Lens partially opaque; fundus glow visibleSpoke-like (cuneiform) or punctate cortical opacities; vision mildly impaired; lens may be slightly swollen (intumescent phase); iris shadow present (oblique illumination shows crescentic shadow on lens - shadow of iris falls on opaque lens)
2. IntumescentSwollen, water-logged lensLens absorbs water, swells, shallow AC - may precipitate acute angle-closure glaucoma; iris shadow prominent
3. MatureTotally white opaque lensAll cortex opacified; NO iris shadow (opacity extends to capsule); pupil appears white/grey (leukocoria); fundus glow absent; vision = perception of light only
4. HypermatureLiquefied/shrunken lensCortex liquefies (morgagnian cataract - nucleus sinks to bottom of liquid cortex); capsule shrunken/wrinkled; iris shadow absent; leak of lens proteins may cause phacolytic glaucoma
Nuclear cataract classification (LOCS grading): graded by colour (NO1-NO6: clear to brown/black; brunescent cataract).

Q3. Trachoma - Definition, Risk Factors, Signs, Symptoms & Management (5 marks)

Definition: Trachoma is a chronic keratoconjunctivitis caused by Chlamydia trachomatis (serovars A, B, Ba, C). It is the world's leading cause of preventable irreversible blindness and is related to poverty, overcrowding and poor hygiene. Recurrent infection elicits chronic immune response (Type IV delayed hypersensitivity).
Risk Factors:
  • Poverty, overcrowding
  • Poor facial and personal hygiene
  • Inadequate access to water and sanitation
  • Young children (most vulnerable - family childcare group is main reservoir)
  • Fly (important vector) and direct contact with ocular/nasal discharge
  • Endemic regions (sub-Saharan Africa, Middle East, South/Southeast Asia)
WHO Grading - Active (Inflammatory) Stage:
  • TF (Trachomatous Inflammation - Follicular): ≥5 follicles on upper tarsal conjunctiva
  • TI (Trachomatous Inflammation - Intense): intense inflammatory thickening obscuring >50% of tarsal vessels
WHO Grading - Cicatricial (Chronic) Stage:
  • TS (Trachomatous Scarring): white fibrous lines/bands on tarsal conjunctiva (Arlt's line)
  • TT (Trachomatous Trichiasis): ≥1 eyelash rubbing the eyeball
  • CO (Corneal Opacity): corneal opacity over pupil area → blindness
Signs:
  • Mixed follicular/papillary conjunctivitis (upper tarsal/forniceal predominantly)
  • Mucopurulent discharge
  • Pannus formation (fibrovascular ingrowth into superior cornea)
  • Herbert's pits (limbal follicles → scarred pits pathognomonic of trachoma)
  • Arlt's line (horizontal tarsal scar)
  • Trichiasis & entropion (inturned lashes abrading cornea)
  • Corneal ulceration, vascularization, opacity → blindness
Symptoms:
  • Mucopurulent discharge
  • Foreign body sensation, irritation
  • Photophobia
  • Reduced vision (in advanced stages)
Management (SAFE Strategy - WHO):
  • Surgery - for entropion/trichiasis (bilamellar tarsal rotation)
  • Antibiotics - single dose azithromycin 20 mg/kg (max 1 g) orally - treatment of choice; alternatives: erythromycin 500 mg BD x14 days, doxycycline 100 mg BD x10 days; topical 1% tetracycline ointment (less effective)
  • Facial cleanliness (critical preventative measure)
  • Environmental improvement (water, sanitation, fly control)
Note: Tetracyclines contraindicated in pregnancy and children under 12 years.

Q4. Keratoplasty - Types and Indications (5 marks)

Definition: Corneal transplantation (keratoplasty) is the replacement of diseased host corneal tissue with healthy donor cornea.

Types:

I. Penetrating Keratoplasty (PK) - Full thickness
  • Entire corneal thickness replaced (all 5 layers)
  • Common graft size: 7.5 mm; donor button 0.25 mm larger than host
  • Secured with continuous or interrupted sutures
  • Indication: disease involving all layers
II. Lamellar Keratoplasty - Partial thickness
SubtypeLayer replacedKey indications
Superficial Anterior Lamellar (SALK)Superficial stroma/epitheliumSuperficial corneal scars, recurrent corneal erosion
Deep Anterior Lamellar Keratoplasty (DALK)Full stroma down to Descemet's membraneKeratoconus, stromal dystrophies, anterior stromal scars - with healthy endothelium
Descemet's Stripping Automated Endothelial Keratoplasty (DSAEK)Descemet + endotheliumFuchs' endothelial dystrophy, bullous keratopathy
Descemet's Membrane Endothelial Keratoplasty (DMEK)Descemet membrane onlySame as DSAEK; faster recovery, better vision

Indications (by purpose):

1. Optical (to improve vision):
  • Keratoconus (most common indication for DALK)
  • Corneal scars (post-infection, trauma)
  • Corneal dystrophies (Fuchs', lattice, granular)
  • Pseudophakic bullous keratopathy
  • Corneal degenerations
2. Tectonic (to restore structural integrity):
  • Descemetocele (impending perforation)
  • Perforated corneal ulcer
3. Therapeutic (to remove infected tissue):
  • Microbial keratitis unresponsive to antimicrobials (fungal, Acanthamoeba)
4. Cosmetic (rare):
  • Improve appearance of an unsightly corneal scar in blind eye

Q5. Congenital Cataract - Types, Risk Factors & Management (5 marks)

Incidence: ~3 in 10,000 live births; two-thirds bilateral.

Types (morphological):

  • Nuclear cataract - most common; involves embryonic nucleus; bilateral
  • Lamellar (zonular) cataract - affects a specific zone; most common type requiring surgery
  • Posterior polar - posterior subcapsular/capsular; associated with posterior lenticonus
  • Anterior polar - small, central, usually stationary
  • Sutural - Y-suture opacities; usually visually insignificant
  • Coronary - peripheral cortical, club-shaped opacities
  • Total/complete - entire lens opaque; most visually significant
  • Oil droplet - galactosaemia (reversible with diet)
  • Blue dot (cerulean) - benign, common

Risk Factors / Aetiology (Rule of Thirds):

  • 1/3 hereditary - Autosomal dominant (most common genetic cause)
  • 1/3 systemic disease (below)
  • 1/3 idiopathic/unknown
Metabolic causes:
  • Galactosaemia (galactose-1-phosphate uridyl transferase deficiency) - oil droplet opacity
  • Galactokinase deficiency
  • Lowe (oculocerebrorenal) syndrome - X-linked recessive
  • Hypocalcaemia (hypoparathyroidism)
  • Mannosidosis
Intrauterine infections (TORCH):
  • Rubella - most important; pearly nuclear cataract, microphthalmos, deafness, cardiac defects; ~15% get cataract
  • Toxoplasmosis, CMV, HSV, varicella
Other systemic associations:
  • Down syndrome (trisomy 21) - sutural, blue dot opacities
  • Chromosomal abnormalities (trisomy 13, 18)
  • Myotonic dystrophy
Ocular causes: Persistent fetal vasculature (PFV), anterior segment dysgenesis

Management:

Surgical timing:
  • Bilateral dense cataracts: surgery at 4-10 weeks (to prevent stimulus deprivation amblyopia)
  • Unilateral dense cataract: surgery by 6 weeks (some advocate 4-6 weeks); earlier is better
  • Bilateral partial cataracts: defer surgery; monitor; may not need operation
Surgery:
  • Anterior capsulorhexis + aspiration of lens matter
  • Posterior capsulotomy (capsulorhexis) + anterior vitrectomy (mandatory in children - posterior capsule opacification is universal if retained)
  • IOL implantation (if appropriate; timing controversial in infants)
Post-operative:
  • Aggressive anti-amblyopia therapy (patching of better eye)
  • Optical correction (contact lens/spectacles) - critical
  • Treatment of associated glaucoma (20% risk by 5 years)
  • Monitor for posterior capsular opacification, secondary membranes, Soemmering ring

Q6. National Blindness Control Programme (5 marks)

India's National Programme for Control of Blindness & Visual Impairment (NPCBVI) was launched in 1976 as a 100% centrally sponsored programme.
Aims/Objectives:
  • Reduce the prevalence of blindness from 1.1% (1971) to <0.3%
  • Provide comprehensive eye care services to all sections of the population
  • Develop sustainable infrastructure and human resources for eye care
Components/Key Interventions:
ComponentDetails
Cataract surgeryPrimary focus; target of conducting millions of surgeries/year; shift to IOL implantation (phacoemulsification)
School Eye ScreeningDetection of refractive errors, squint in school children; free spectacle distribution
Control of Blindness from TrachomaSafe water, sanitation, antibiotics in endemic areas
Management of Diabetic RetinopathyLaser treatment centres at district level
Low Vision ServicesLow vision aids and rehabilitation
Control of Vitamin A DeficiencySupplementation for children (Vitamin A prophylaxis programme)
Glaucoma screeningAwareness and early detection
Human Resource DevelopmentTraining ophthalmic officers, nurses, vision technicians
Organizational structure:
  • National level: Directorate General of Health Services
  • State level: State Blindness Control Society
  • District level: District Blindness Control Society (DBCS)
  • Community level: Vision centres, vision technicians
Recent Updates (NPCBVI):
  • Renamed from NPCB to NPCBVI to include low vision
  • Integrated into National Health Mission (NHM)
  • Vision 2020 "The Right to Sight" initiative (India joined 1999)
  • Focus on comprehensive, community-based eye care rather than only cataract surgery
Major causes of blindness targeted (India):
  1. Cataract (~66%)
  2. Refractive errors
  3. Glaucoma
  4. Corneal blindness
  5. Posterior segment diseases

Q7. Pathological Myopia and Fundus Findings (5 marks)

Definition: Pathological (degenerative/malignant) myopia is a condition where axial elongation is progressive and excessive (typically >-6D or axial length >26 mm), associated with degenerative changes in the sclera, choroid, retina, and vitreous. It is distinct from simple myopia.
Epidemiology:
  • More common in East Asian populations
  • Sixth most common cause of visual impairment worldwide
Pathophysiology:
  • Uncontrolled axial elongation of the globe
  • Mechanical stretching and thinning of the posterior segment
  • Traction and tearing of the choroid/RPE/retina

Fundus Findings:

1. Disc changes:
  • Tilted optic disc (oblique insertion of optic nerve)
  • Peripapillary atrophy (PPA) - crescentic area of chorioretinal atrophy around disc (myopic crescent)
  • Temporal/inferior conus (crescent)
2. Posterior staphyloma:
  • Localized outpouching of the posterior globe (thinned sclera/choroid/retina)
  • Seen on fundus as a deep concavity centred at macula or around disc
3. Macular changes:
  • Lacquer cracks - breaks in Bruch's membrane appearing as yellowish linear streaks; ~4% risk of CNV at each crack
  • Fuchs' spot (Forster-Fuchs spot) - pigmented lesion at macula from subretinal neovascularization/haemorrhage
  • Choroidal neovascularization (CNV) - subretinal membrane, causes central visual loss
  • Myopic maculopathy - chorioretinal atrophy with thin, transparent retina
  • Macular hole (high risk of retinal detachment)
  • Macular schisis (retinoschisis) - intraretinal fluid splitting
4. Peripheral changes:
  • Lattice degeneration - areas of peripheral retinal thinning with white lines and pigment
  • Snail-track degeneration
  • White without pressure
  • Retinal breaks/holes - predispose to rhegmatogenous retinal detachment
5. Vitreous changes:
  • Premature vitreous degeneration and posterior vitreous detachment (PVD)
  • Weiss ring (floater from PVD)
6. Choroidal changes:
  • Diffuse chorioretinal atrophy - pale, tigroid/tessellated fundus (choroidal vessels visible through thin RPE)
Complications:
  • Retinal detachment (much higher risk than normal eyes)
  • Choroidal neovascularization
  • Macular hole
  • Glaucoma (3-4x increased risk)
  • Cataract (posterior subcapsular/nuclear)
Management:
  • Anti-VEGF (ranibizumab, bevacizumab) for myopic CNV
  • Monitoring with OCT
  • Low vision aids if needed
  • Prompt treatment of retinal detachment (vitrectomy ± scleral buckle)
  • Atropine 0.01% (children - to slow myopia progression)
Sources: Kanski's Clinical Ophthalmology: A Systematic Approach, 10th Edition; Harrison's Principles of Internal Medicine, 22nd Edition.
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