Presentation on theme: "Cataract Tahir Masoud 17 th March 2010. Definition A cataract is an opacity in the natural lens that can cause visual problems."— Presentation transcript:
Cataract Tahir Masoud 17 th 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 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
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.
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 17 th 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 (3 rd ed), 2008.
Secondary open-angle glaucomas Trauma and secondary glaucoma Lens luxation with acute pupillary block glaucoma Hyphema, total, secondary open-angle glaucoma Online Journal of Ophthalmology:
Risk factors for angle-closure Shallow anterior chamber depth, associated with 1 : – Female gender – Increasing age – Asian (particularly Chinese) origin Shorter globe axial length 1 Environmental factors 1 : – 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 & investigations Slit-lamp examination – applanation tonometry European Glaucoma Society, 2008 National Eye Institute, National Institutes of Health
Examinations & investigations Direct gonioscopy Rich R, courtesy of South East Asia Glaucoma Interest Group (SEAGIG). European Glaucoma Society, 2008
Assessment of the optic disc Observe the scleral ring to size the optic disc Identify the size of the rimExamine 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).
Examinations & investigations Optic nerve head/retinal nerve fibre layer imaging Ki Ho Park, courtesy of South East Asia Glaucoma Interest Group (SEAGIG). Red-free photography Optical coherence tonometry
Examinations & investigations Visual field examination – perimetry Severe loss of visual fieldMild loss of visual field
Filtration surgery trabeculotomy Treating the mechanisms of glaucoma 1,2 1. South East Asia Glaucoma Interest Group (SEAGIG). Asia Pacific Glaucoma Guidelines, European Glaucoma Society. Terminology and Guidelines for Glaucoma (3 rd ed), Medical Rx IOP reduction Laser trabeculoplasty Abnormal anatomy Work with multidisciplinary team to treat systemic problems Contributing diseases Laser 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