Kiran Oli intern optometrist Vidyasagar College Of Optometry And Vision

Science

GLAUCOMA

glaucoma

• A disease of progressive optic neuropathy with loss of retinal neurons and their axons (nerve fiber layer) resulting in blindness if left untreated.

“Glaucoma describes a group of diseases that kill retinal ganglion cells.”

“High IOP is the strongest known risk factor for glaucoma but it is neither necessary nor sufficient to induce the neuropathy.”

Risk factors for glaucoma

• IOP Diabetes• Age Myopia• Race Gender• Family history Cardiovascular• Central corneal disease thickness Hormones

Aqueous humor

• Transparent• Watery fluid• Similar to plasma• Fills the anterior chamber of eye ball

Aqueous humor formation

drainage

CHARACTERISTICS OF IOP

• Normal range: 10-22 mm Hg

• 30-50% of open angle glaucoma patients have IOP <22 mmHg

• Diurnal flucuation normally < 6 mmHg

• Women have slightly higher pressures

Diurnal flucuation

IOP variables

• Gender influences • Normal vs glaucoma

How do we measure IOP?

• Applanation

• Tonopen

• Schiotz

• Non-contact

AT

THE VISUAL FIELD

Why examine the optic nerve?

• Characteristics pattern of damage in glaucoma• Attrition of the 1.0 to 1.2 million retinal

ganglion cell axons passing through.

goals

• Distinguish normal ONH from abnormal.• If abnormal, distinguish glaucoma from other

optic disc pathologies.

How to examine the optic nerve?

• Slit lamp and fundus lens• Stereoscopic viewing• Dilate the pupil if necessary• Direct ophthalmoscope is not

What to look for when examining the ON

• Distinguish normal ONH from abnormal.• If abnormal, distinguish glaucoma from other

optic disc pathologies

What is normal?

normal

Normal

• Vertical disc diameter 1.7-1.8mm• Horizontal cup• Follows the ISNT rule• Yellow-orange or pinkish-yellow rim• Simillar in the two eye• Central retinal vessels slightly nasal to center

size

jumbo large

average small

shape

Typical slightlyVertically oval

round Horizontally oval

More vertically Oval than usual

irregular

ISNT rule

RIM color

Typical:Yellow - orange

Moderate glaucomaStill yellow-orange

Advance glaucoma Still yellow orange

Rim color

• Need to remember

pseudophakicphakic

Similar in two eyes

CDR asymmetry – sign of glaucoma…..only if disc are of the same size

Vessel pattern

typical

More nasal Than usual

more temporalThan usual

Artery and vein apart

Examination for glaucoma

• Disc size• Rim• Vessels• Disc hemorrhage• RNFL• Lamina cribrosa

Disc size

• s

Area = area

Small disc = small cupLarge disc = large cupSpace for 1 – 1.2 million axons

RIM

• Typically – horizontally oval cup, follows INST rule.

• Glaucomatous rim thinning – usually affects superior and inferior.

Rim identification

• Scleral ring • Cup edge• Bending of vessels

Rim identification

• Grey crescent

ISNT rule

Rim - notching

vessels

Bayoneting of vessels

Vessels

• Nasalization not always marked in advance glaucoma

Nasalization no glaucoma Glaucoma with no nasalization

Disc hemorrhage

RNFL

Lamina cribrosa

Weak Moderate Strong

Laminar dots and striationsLarge CDRNasalization of vessels

Violation of INST ruleIsolated disc hemorrhageCup-to-disc asymmetry between same sized optic discsLarge cup for a small discBayoneting of vessels

Neuroretinal rim notchThin retinal rimRNFL defectDisc hemorrhage associated with other indicator

Types of glaucoma

• Congenital glaucoma• Open angle glaucoma• Normal tension glaucoma• Angle closure glaucoma

Congenital Glaucoma

• Symptoms• Irritability• Photophobia• Epiphora• Poor vision

• Signs• Elevated IOP• Buphthalmos• Corneal clouding• Glaucomatous

cupping• Field loss

Open Angle Glaucoma

Risk Factors• IOP Diabetes• Age Myopia• Race Gender• Family history Cardiovascular• Central corneal disease thickness Hormones

Open Angle Glaucoma

Onset: 50+ years of age

Symptoms Usually none May have loss of central and peripheral vision late

Signs Elevated IOP Visual field loss Glaucomatous disk changes

• Pressure rise in POAG is gradual• bilateral, but often asymmetric• Patients often have no symptomsNon- specific complains of painIntermittent blurred vision• Visual loss usually starts in the periphery

Normal tension glaucoma

• Similar to POAExcept that IOP is in the normal range• Risk factorAnemiaHistory of severe blood lossChronic arterial hypotensionDecreased corneal thickness

Angle closure glaucoma

• Less common than POAG• 10% of all glaucoma cases• May be acute, sub-acute or chronic• Usually have some symptoms which help in

diagnosis• Blindness is irreversible, and can occur quickly,

especially with acute form

Angle closure GlaucomaOnset: 50+ years of age

Symptoms• Severe eye/headache pain• Blurred vision• Red eye• Nausea and vomiting• Halos around lights• Intermittent eye ache at night

Signs• Red, teary eye• Corneal edema• Closed angle• Shallow AC• Mid-dilated, fixed pupil“Glaucomflecken”• Iris atrophy• AC inflammation

Acute Angle Closure Glaucoma

Mechanical disruption of flow of aqueous humor from the eye - lens is closure contact to iris- Blocks natural pathway of aqueous through the pupil- Aqueous gets trapped behind the iris- Iris bows forward and further blocks flow of fluid out of eye through the trabecular meshwork

DIAGNOSIS• Gonioscopy • Optic nerve examination• Intraocular pressure• Pachymetry • Visual field• Nerve fiber layer analysis

GLAUCOMATreatment

Medical

Miotics Beta-blockers Carbonic anhydrase inhibitors Prostaglandin analogues Alpha-2 agonists

TreatmentSurgical

Argon laser trabeculoplasty Trabeculectomy Filtering procedure Cyclocryotherapy Cyclolaser ablation Iridotomy

Argon laser trabeculoplasty

Trabeculectomy

Iridotomy

references

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3588129/

• Dr. Najeeb lectures/articles• Dr. Hannah de Guzman lectures/articles• Dr. Shan lin lectures• Dr. Leon W. Herndon, Jr lectures/articles

Thank you