GLAUCOMA

GLAUCOMA

• Any of
• ↑↑ IOP
• Visual field defect
• Fundus changes → Cupping
• C:D ratio > 0.3

Theories of Glaucoma

• Ganglion cells are affected in glaucomatous optic atrophy

Pathophysiology & Types

1. Optic neuropathy:
• Progressive, characteristic optic disc changes.

2. Irreversible visual field defects.

3. IOP: Normal (11-21 mmHg) or raised.

• Glaucoma occurs due to:
• Increased aqueous production.
• Decreased aqueous clearance.

• Aqueous Flow:
• Ciliary processes secrete aqueous → Trabecular meshwork (site of outflow) → Schlemm’s canal → Aqueous vein → Episcleral vein.

Malignant glaucoma

• After Intraocular Surgery

• Common in Hypermetropic eyes

• Causes Ciliary block & aqueous misdirection → Glaucoma

• Rx
• Atropine
• Cycloplegic → Relieves ciliary block

• NOTE: Atropine C/I in POAG

High-Risk Factors for Progression of Ocular Hypertension to POAG

• Ageing

• Raised IOP
• > 30 mmHg

• Central Corneal Thickness (CCT)
• < 550 microns

• Optic Disc Changes
• Increased Cup : Disc ratio > 0.7

• Splinter Hemorrhages

• Pattern Standard Deviation (PSD) on Humphrey Visual Field Analyzer

Investigations

Optic Disc Examination

• Direct ophthalmoscopy:
• Magnification 15 times.
• Visualizes central fundus.
• Disadvantage: No binocular vision.

• Slit lamp biomicroscopy:
• Magnification with +90 D lens.

Visual Field Examination (Perimetry)

• Manual
• listers perimeter

• Automated
• Humphrey field analyser

• Kinetic:
• Moving targets (not preferred).

• Static:
• Idle targets (e.g., Humphrey Field Analyzer (HFA)).

• Normal Visual Field:
• Horizontally oval with an infero-nasal notch.
• Superior: Minimum Visual field
• Temporal: Maximum Visual field

IOP Measurement (Tonometry)

• Indentation tonometry:
• Schiotz tonometer (not preferred).

• Non-contact tonometry:
• Choice for screening in camps.
• Puff air
• Ocular response analyser (Advanced)

• Tonopen
• For scarred cornea

• Rebound tonometer
• For self-monitoring
• Self monitoring to prevent Rebound

• Transpalpebral tonometry 
• Diaton, Proview
• Visualized through eyelid.

• Fixed area tonometers:
• Goldmann’s
• Mackey marg:
• Choice for edematous irregular cornea.
• Mnemonic: Margam illathapo Mackey marg

• Goldmann’s Applanation tonometry 
• Principle: Imbert Fick law (Pressure = Force/Area).
• Uses fluorescein dye and cobalt blue light
• Gold standard.
• Mnemonic: Gold is gold
• Most commonly done

• Pascals tonometer
• Now better than Goldmann
• Pascal was a better man

• Maklakov tonometer
• Variable application surface
• Makkalkk variable swabavam

Examination of Anterior Chamber Angle

• Closed Her in Anterior Chamber
• Heri Ick () gone (Gonioscopy) when Flashed (Oblique flashlight) light

• Van Herick’s Method:



• Compares
• peripheral anterior chamber depth (PACD) and
• corneal thickness (CT) using slit lamp
• PACD = CT:
• Open angle.
• PACD < 1/4 CT:
• Shallow AC (closed/closing angle).
• Mnemonic: Her in a Van → with slit lamp check her thickness → Anterior chamber

• Oblique Flashlight Test:



• Shadow over nasal iris ⇒ Angle closure glaucoma.

• Gonioscopy:



• Best method
• But gold standard is Goldman
• Principle: Overcomes total internal reflection.
• Contraindication: Dilated pupil.
• Direct gonioscope:
• Richardson/ Koeppe

• Structures seen: Mnemonic: I can see till schwalbe line
• Iris
• Ciliary body.
• Scleral spur.
• Trabecular meshwork.
• Schwalbe’s line (Peripheral termination of Descemet’s membrane).

Primary Open Angle Glaucoma (POAG)

• Mnemonic:
• POAG → Open → Open (Optineurin) My (Myocilin) World 360 degree (WDR 36)
• Old people (Senile) become Alpha (Alpha is specific) → Rims (Neuroretinal rim)
• Amina (Lamina) in net (Bayonetting) dress with cups (Vertical cupping)
• and dots (Laminar dot sign)

• Chronic disease.

• Common in age >50 years.

• Positive family history.

• Genes: WDR 36, optineurin, myocilin.

Symptoms

• Headache.

• Delayed dark adaptation.

• Frequent change in presbyopic spectacles.

Criteria

• IOP >21 mmHg OR

• >5 mmHg difference between both eyes.

• > 8 mmHg difference in diurnal variation

Other signs

• RAPD or Marcus Gunn Pupil

Optic Disc Changes

• Loss of neuroretinal rim (inferior).

• Vertical cupping (c/d ratio >0.5).

• Bayonetting sign (double angulation of blood vessel)

• Laminar dot sign.

• Peripapillary atrophy:
• Alpha zone: Specific.
• Beta zone: Also seen in myopia.

Visual Field Changes

• Earliest sign on perimetry:
• Isopter contraction (Constriction of peripheral VF)

• Baring of blind-spot.

• In bjerrum area affecting nerve fibres
• Paracentral scotoma
• Earliest clinically visible manifestation
• Seidel’s scotoma:
• Comma shaped, connects with blind spot.
• Bjerrum/Arcuate scotoma:
• Arches to opposite side, affects arcuate nerve fibres in Bjerrum’s area.
• Ring/Double arcuate scotoma:
• Central vision spared
• Roenne’s nasal step:
• Due to unequal contraction of upper & lower hemispheres.

• → Loss of Central vision

• → Loss of temporal island vision (last to be lost).

Normal Tension Glaucoma (NTG)

• Defined by: OD changes + VF changes + Normal IOP.

• Commonly associated with:
• Raynaud phenomena.
• migraine.
• ↓ blood flow velocity in ophthalmic artery.

• Rx: Lifestyle changes

Adrenochrome deposits

• Seen in conjunctiva

• After chronic use of topical epinephrine for Glaucoma

Medical Management (Topical drugs):

Surgical Management:

• Increases trabecular outflow.

1. CLOSED SURGERY

Laser trabeculoplasty:

• Acts on trabecular meshwork (TM).

• Improves aqueous outflow.

• Best response:
• Pseudoexfoliation
• Pigmentary glaucoma

• Photocoagulation
• Argon laser (514 nm)
• SLT (Selective LT) (532 nm)
• TOC for prophylaxis in other eye

• Mnemonic: Do Urgent (Argon) Laser in POAG, but Selective (SLT) laser in other eye

Indications

• OAG uncontrolled on medical therapy

• OAG with poor compliance

• OAG with poor drug tolerance

• Pseudoexfoliative glaucoma.

• Pigmentary glaucoma.

• Angle-closure glaucoma
• Only after patent iridotomy.
• Or Anterior Synechiae > 270 degree

• Temporary IOP control
• When glaucoma surgery must be deferred

Contraindications

• Inflammatory glaucoma

• Advanced glaucoma

• Poor visualization of TM
• Due to synechiae.
• Laser cannot act on TM.

2. OPEN SURGERY

a. Penetrating Surgery

• Trabeculectomy: 
• Best surgery.
• Creating fistula b/w AC and subtenon space → Aqueous drainage.

b. Non-penetrating Surgery:

• Viscocanalostomy

• Deep sclerectomy

SURGERY WITH IMPLANTS

• Done for resistant glaucoma.

1. Seton Surgery

• Implants a glaucoma drainage device.

• Parts:
• Tube → Inserted into AC (Sub-tenon or subconjunctivally) → Enables outflow.
• Plate → Positioned in sub-tenon space → Collects fluid.

• Types of Drainage Device



• Non-valved:
• Continuous outflow.
• Examples: 
• Express mini shunt (made of stainless steel) → like express train
• Baerveldt device → 4 Bore wells
• Malteno device → Malt → Motta
• Valved:
• Stops outflow when required.
• Example: Ahmed Glaucoma Valve (AGV).
• Ahmed’s Sperm

2. MIGS (Minimally Invasive Glaucoma Surgery).

• Stents through TM (Trabecular Meshwork) → Enables outflow.

• Advantages:
• Small incision
• ↓ Chance of post-operation infection (e.g., Endophthalmitis)

Ex-PressTM implant

Ahmed glaucoma valve

Molteno implant

Baerveldt implant

Primary Angle Closure Glaucoma (PACG)

• Acute disease.

• Other Causes:
• TCA → Clomipramine, Amitryptilline
• Citalopram

Pathogenesis

• → No aqueous flow (posterior to anterior chamber)

• → Iris pushed forward (Iris bombe)

• → Irido-trabeculo-corneal contact

• → Peripheral anterior synechiae formation

• → PACG.

Clinical Features

• Headache.

• Severe eye pain (IOP >40 mmHg, rock hard eye).

• High IOP disrupts endothelium causing corneal edema.

• Distorted vision (due to hazy cornea).

• Redness of eye.

• Vomiting.

• Halos around lights (prismatic dispersion due to corneal edema).

Signs

• Eclipse sign:
• Shadow over nasal iris
• Oblique flashlight test

• Posterior synechiae
• adhesion between pupillary margin & lens

• Anterior synechiae
• between iris and cornea

• Both anterior and posterior synechiae are seen

• Vogt’s triad: VOGT → Vertically Oval, Glaucomflecken, aTrophy Iris
1. Iris aTrophy.
2. Glaucomflecken
• Lens epithelium necrosis → white or grey lens opacities




3. Vertically oval mid-dilated pupil (fixed).

• Note: ACG is precipitated in dark places (e.g., movie halls).

Treatment

• Initial Treatment:
• IV Mannitol (DOC)
• Oral acetazolamide
• Pilocarpine eyedrops
• miotic, given after ↓IOP;
• pulls iris to center and opens angle
• Mnemonic: Pilocarpine → Put a carpet and relax → parasymp → miosis
• Atropine should not be given

• Definitive Treatment:
• Laser iridotomy (TOC):



• Nd-YAG Laser
• Performed between 11 o’clock & 1 o’clock
• Equalizes pressure.

• If anterior synechiae > 270 degree
• Trabeculectomy + Mitomycin C

NOTE: Complicated cataract

Congenital Glaucoma

Symptoms

• Triad
• Photophobia
• earliest symptom
• Lacrimation
• m/c symptom
• Blepharospasm.

Signs

• Open angle Glaucoma due to Trabecular dysgenisis

• Hazy cornea
• Earliest sign

• Buphthalmos:
• Enlarged eyeballs.
• Deep AC.
• Increased axial length (myopia).
• Corneal diameter >13 mm.
• Blue sclera.

• Haabs striae

Striae	ㅤ	ㅤ
Haab’s striae	• Horizontal breaks in Cornea	• Congenital glaucoma
Vogt’s striae	• Vertical stretching • In Slit lamp • Vogt → Valich stretch cheyth • Striae → Stretch → Slit lamp	• Keratoconus

• Cornea ↑↑, Axial length ↑↑↑, Anterior chamber ↑↑

• Mnemonic:
• Child (Congenital) haab (Haab) glowing (glaucoma) blue () eye

Gonioscopic Findings

• Anterior iris insertion

• Barkan membrane

• Loch Ness monster phenomenon: Loops of vessels visible

• Mnemonic: Monster (Lochness monster) came Barking (Barkan membrane) → Child with blue eyes Gone (Gonioscopy)

Treatment

• Trabeculectomy + trabeculotomy (TOC).
• Trabeculectomy: Cutting of some TM
• Trabeculotomy: Formation of holes in the remaining TM

• If cornea is clear
• Goniotomy
• Needle piercing of Trabecular Meshwork using a gonioscope for visualization.
• Can be performed if cornea is clear (if onset >2 yrs)

Secondary Congenital/Developmental Glaucoma

• Mechanism: irido trabeculo corneal dysgenesis

• Causes:
• Axenfeld-Rieger syndrome
• Glaucoma in 50% cases
• Posterior embryotoxon:
• Anteriorly displaced Schwalbe's line
• Peter's anomaly
• Aniridia: Ectopia lentis and glaucoma
• Phacomatosis: NF, Sturge weber syndrome
• Phac () peter () with no iris () but axe ()

Secondary Glaucoma

Lens Induced: