Cataract

Tahir Masoud17th March 2010

Definition

• A cataract is an opacity in the natural lens that can cause visual problems.

Why is it important?

• Age-related cataract is responsible for 48% of world blindness, which represents about 18 million people, according to the World Health Organization (WHO).

• At least 5-10 million new visually disabling cataracts occur yearly, with modern surgical techniques resulting in 100,000-200,000 irreversibly blind eyes.

• 1.2% of the entire population of Africa is blind, with cataract causing 36% of this blindness.

• In a survey conducted in 3 districts in the Punjab plains, the overall rates of occurrence of senile cataract was 15.3% among 1269 persons examined who were aged 30 years and older and 4.3% for all ages. This increased markedly to 67% for ages 70 years and older.

• In the UK 30% of persons of 65 years and over have visually impairing cataract in one or both eyes.

• It is estimated that 2.4 million people aged 65 and older in England and Wales have visually impairing cataract in one or both eyes

• An analysis of blind registration forms in the west of Scotland showed senile cataract as one of the 4 leading causes of blindness.

Anatomy

• The lens is surrounded by a thick lens capsule which is the basement membrane of the lens epithelial cells.

• Epithelial cells at the lens equator continue to be produced throughout life

• Older lens fibres are compressed into a central nucleus

• Younger fibres around the nucleus make up the cortex.

Causes

• Aging • Long-term ultraviolet (UV) light, especially

from sunlight • Systemic disease

– Diabetes– Myotonic dystrophy– Atopic dermatitis– Neurofibromatosis type 2

• Past eye infections, injuries or surgery • Smoking • Drugs

– Steroids– Chlorpromazine– Busulphan– Amiodarone– Gold

• Hereditary

Classification• Morphological

– Cortical– Nuclear– Subcapsular– Christmas tree

• Maturity– Immature– Mature– Hypermature– Morgagnian

• Age– Congenital– Presenile– Senile

• Cause– Primary– Secondary

Congenital cataract

• Present at birth or appear shortly thereafter• These cataracts may show many different

patterns. • The opacity may be confined to the area of

the embryonic or fetal nucleus with clear cortex surrounding this.

• Prenatal infections: Rubella, CMV, HSV, Varicella

• Maternal ingestion of thalidomide, steroids • Systemic disease

– Metabolic: Galactosemia, Galactokinase deficiency

• Hereditary– Autosomal dominant– Recessive– X-linked

• Chromosomal abnormalities– Down syndrome (trisomy 21)– Patau syn (trisomy 13)– Edward syn (trisomy 18)

Secondary Cataract

• Develop as a direct effect of eye diseases – glaucoma,– iritis– eye tumors ,– retinitis pigmentosa– retinal detachment.

Symptoms

• Blurred vision• Distortion• Glare• Diplopia• Myopic shift

Assessment

• Vision acuity test

• Slit lamp

• Ophthalmoscopy

• In most cases, eye drops are used to dilate pupils before the exam.

• Tonometry

Treatment

• If symptoms from a cataract are mild, a change of glasses may be all that is needed for you to function more comfortably.

• Surgery is the only way to remove the cataract.

• Cataract surgery should be considered when cataracts cause enough loss of vision to interfere with daily activities.

Types of cataract surgery

• Intracapsular

• Extracapsular– Phacoemulsification– ECCE

• Extracapsular cataract extraction is the preferred method of cataract surgery

• It preserves the posterior portion of the lens capsule

• Posterior chamber IOL can be implanted in the capsular sac

• An IOL is a tiny, transparent, convex lens made of different materials which is inserted in the eye during surgery.

Glaucoma

Tahir Masoud 17th March 2010

Glaucoma

• A group of disorders in which there is eventual development of an optic neuropathy with characteristic changes at the optic nerve head.

• Depression of visual function and eventual loss of visual field.

• Raised intra-ocular pressure often appears to be a significant factor in its development.

Why is glaucoma important

• Glaucoma causes significant visual disability in the UK, accounting for 15% of registrable blindness

• In a white population, POAG occurs in approximately 1-2% of the population over 40, increasing with age to 4% or more of the over 80-year olds.

Iris processes

Scleral spur

Schlemm canal

Trabeculum

Schwalbe line

• Aqueous is actively secreted by the non-pigmented epithelium of the pars plicata (anterior) of the ciliary body

• Approximately 90% of aqueous leaves through the trabeculum into the Schlemm canal and drains into episcleral veins (trabecular or conventional route)

• 10% of aqueous passes across the face of the ciliary body into suprachoroidal space and then drains into the venous system (uveoscleral or unconventional route)

• IOP can be reduced by– Reducing the aqueous production– Increasing the aqueous outflow

Small physiological cup

Large physiological cup

Total glaucomatous cupping

Normal vertical cup-disc ratio is 0.3 or less

2% of population have cup-disc ratio > 0.7

Classification

• Primary congenital forms• Primary open-angle glaucomas (POAG)

– Primary juvenile glaucoma– POAG/high pressure glaucoma– POAG/normal pressure glaucoma– Primary open-angle suspect– Ocular hypertension

European Glaucoma Society. Terminology and Guidelines for Glaucoma (3rd ed), 2008.

• Secondary open-angle glaucomas– Secondary open-angle glaucomas caused by

ocular disease– Iatrogenic secondary open-angle glaucomas

• Primary angle-closure glaucoma(PACG)– Pupillary block– Plateau iris syndrome

Primary open-angle glaucomas (POAG)

Glaucomatous optic atrophy

Normal pressure glaucoma

Online Journal of Ophthalmology

Primary angle-closure

Acute angle-closure

Acute/intermediate angle-closure

Online Journal of Ophthalmology

Online Journal of Ophthalmology

Glaucoma classificationSecondary open-angle glaucomas caused

by ocular disease

• Exfoliative glaucoma• Pigmentary glaucoma• Lens-induced secondary open-angle glaucoma• Glaucoma associated with intraocular haemorrhage• Uveitis glaucoma• Glaucoma due to intraocular tumours• Glaucoma associated with retinal detachment• Open-angle glaucoma due to ocular trauma

European Glaucoma Society. Terminology and Guidelines for Glaucoma (3 rd ed), 2008.

Secondary open-angle glaucomas

Pigment dispersion syndrome

Exfoliative glaucoma

Heterochromic iridocyclitis fuchs (uveitis), secondary open-angle glaucoma

Online Journal of Ophthalmology: www.onnjoph.com

Lens-induced (phacolytic) glaucoma

Phacolytic acute open-angle glaucomaPhacolytic glaucoma, histology

Phacolytic glaucoma Phacomorphic malignant glaucoma

Online Journal of Ophthalmology: www.onnjoph.com

Secondary open-angle glaucomasNeovascular secondary glaucoma

Neovascular secondary angle-closure glaucoma

Florid iris neovascularisation

Online Journal of Ophthalmology: www.onnjoph.com

Secondary open-angle glaucomasTrauma and secondary glaucoma

Lens luxation with acute pupillary block glaucoma

Hyphema, total, secondary open-angle glaucoma

Online Journal of Ophthalmology: www.onnjoph.com

Risk factors for angle-closure

• Shallow anterior chamber depth, associated with1:– Female gender– Increasing age– Asian (particularly Chinese) origin

• Shorter globe axial length1 • Environmental factors1:

– Seasonal variation– Extreme temperatures– Prolonged periods indoors in a dark environment

1. Foster PJ. Semin Ophthalmol 2002;17:50–58.

Patient history

• POAG is often asymptomatic• Angle-closure glaucoma

– Eye pain and redness– Halos– Headaches

South East Asia Glaucoma Interest Group (SEAGIG). Asia Pacific Glaucoma Guidelines, 2003.

• Ophthalmic history– Trauma, previous eye surgery or laser, previous

ophthalmic medications• Medication history• Social history• Family history

– Risk factors in family– Blindness or eye disease in the family

Examinations & investigations

• Visual acuity• Slit-lamp examination• Applanation tonometry• Gonioscopy• Optic nerve head and retinal nerve fibre layer

evaluation• Visual field examination (perimetry)• Pachymetry

Examinations & investigationsSlit-lamp examination

Acute angle-closure glaucoma

Online Journal of Ophthalmology

Examinations & investigationsSlit-lamp examination – applanation

tonometry

European Glaucoma Society, 2008

National Eye Institute, National Institutes of Health

Examinations & investigationsDirect gonioscopy

Rich R, courtesy of South East Asia Glaucoma Interest Group (SEAGIG). www.seagig.org

European Glaucoma Society, 2008

Assessment of the optic disc

Observe the scleral ring to size the optic disc

Identify the size of the rim Examine the RNFL

Examine the region of the peripapillary atrophy

Look for retinal and optic haemorrhages

Photographs by Ki Ho Park, courtesy of South East Asia Glaucoma Interest Group (SEAGIG). www.seagig.org

Examinations & investigationsOptic nerve head/retinal nerve fibre layer

imaging

Ki Ho Park, courtesy of South East Asia Glaucoma Interest Group (SEAGIG). www.seagig.org

Red-free photographyOptical coherence tonometry

Examinations & investigationsVisual field examination – perimetry

Severe loss of visual fieldMild loss of visual field

Filtration surgery trabeculotomy

Treating the mechanisms of glaucoma1,2

1. South East Asia Glaucoma Interest Group (SEAGIG). Asia Pacific Glaucoma Guidelines, 2003.2. European Glaucoma Society. Terminology and Guidelines for Glaucoma (3 rd ed), 2008.

Medical Rx

Laser trabeculoplasty

Work with multidisciplinary

team to treat systemic problemsLaser iridoplasty

Iridotomy

Lens extraction Vitreous surgery

Glaucoma treatment

• Pharmacological medication• Laser treatment • Surgery

Objective: to review the different options for treatment of underlying disease mechanisms and abnormal eye anatomy

• Beta-blockersBeta-blockers– BetaxololBetaxolol– TimololTimolol

• Alpha-2 agonistsAlpha-2 agonists– BrimonidineBrimonidine– ApraclonidineApraclonidine

• Prostaglandin analoguesProstaglandin analogues– BimatoprostBimatoprost– LatanoprostLatanoprost– TravoprostTravoprost

• Miotics– Pilocarpine

• Carbonic anhydrase inhibitorsCarbonic anhydrase inhibitors– Systemic: AcetazolamideSystemic: Acetazolamide– Topical: Dorzolamide, BrinzolamideTopical: Dorzolamide, Brinzolamide

Laser treatmentPrimary open-angle glaucoma

• Laser trabeculoplasty – outflow enhancement• Cyclophotocoagulation – inflow reduction in end-stage

Laser treatmentAngle closure and angle-closure glaucoma

• Laser iridotomy – pupillary block relief• Laser iridoplasty (gonioplasty) – modification of iris contour• Cyclophotocoagulation – inflow reduction for end-stage glaucoma

SurgeryIncisional surgery options for glaucoma

Characteristics requiredCharacteristics required Type of surgeryType of surgery

Open-angle glaucoma

Outflow enhancementGlaucoma draining

Filtering surgery*Drainage device

Chronic angle-closure glaucoma

Pupillary block reliefOutflow enhancementWidening of anterior chamber

angle inlet

IridectomyTrabeculectomyLens extraction

Acute angle closure

(± glaucoma)

Pupillary block reliefOutflow enhancementAngle surgeryWidening of anterior chamber

angle inlet

IridectomyTrabeculectomyGoniosynechialysisLens extraction

Childhood glaucoma

Angle SurgeryOutflow enhancement Glaucoma drainage

Goniotomy/trabeculotomyTrabeculectomy†

Drainage device