650 likes | 748 Vues
Diseases of the Lens. Doç.Dr.Raciha Beril Küçümen Yeditepe University Department of Ophthalmology 2015 - 2016 Educational Year. AIM. Learning the diagnosis and treatment of lens diseases . Learning the relationship between lens diseases and other systemic diseases. OBJECTIVE.
E N D
Diseases of the Lens Doç.Dr.Raciha Beril Küçümen Yeditepe University Department of Ophthalmology 2015 - 2016 Educational Year
AIM • Learning the diagnosis and treatment of lens diseases. • Learning the relationship between lens diseases and other systemic diseases.
OBJECTIVE • To be able to completely list the etiology, classification, signs and symptoms, and different types of cataract. • To be able to completely write the diseases and syndromes that cause lens dislocation. • To be able to completely list lens shape disorders. • To be able to completely list of cataract surgical techniques and technology used in modern cataract surgery.
Cataract • Greek “katarraktes” : Waterfall / Şelale
Cataract • Any congenital or acquired opacity in the lens capsule or substance is called cataract.
Classification of cataract • Aetiological • Morphological • According to maturity • According to age of onset
Aetiological • Senile • Presenile • Traumatic • Metabolic • Toxic • Complicated (secondary) • Maternal infection • Maternal drug ingestion • Syndromes • Hereditary
Cataract • Age - related cataract is a very common cause of visual impairment in older adults. • In cross - sectional studies the prevalence of cataract is 50% in people between the ages of 65 and 74 increasing to 70% in those over the age of 75. • The pathogenesis of age - related cataract is multifactorial and not completely understood.
Senile • Subcapsular: Anterior or posterior.Patients with posterior subcapsuler cataract have more diminished near vision than their distance vision. • Nuclear: Its frequently associated with myopia due to an increase in the refractive index of the lens and also with increased spherical aberration. Some individuals read without spectacles a condion referred as second sight • Cortical: Anterior, posterior, equatorial. • Christmas Tree cataract is uncommon , characterized by polychromatic, needle-like deposits in cortex and nucleus - myotonic dystrophy
Subcapsular cataract Anterior Posterior
Nuclear cataract Progression • Increasing nuclear opacification • Exaggeration of normal nuclear • ageing change • Causes increasing myopia • Initially yellow then brown
Cortical cataract Progression Progressive radial spoke-like opacities Initially vacuoles and clefts
Traumatic: • Penetrating(intraocularforeign body, siderosisbulbi, chalcosis) • Concussion • İnfraredirradiation(glass-blowers’ cataract) • Electricalinjury • Chemicalinjuries • Ionizingradiation(oculartumorssuch as retinoblastoma) • Ultravioletradiation Trauma is themostcommoncause of unilateralcataract in youngindividuals.
Causes of traumatic cataract Concussion ‘Vossius’ ring from imprinting of iris pigment Flower-shaped Penetration Other causes • Ionizing radiation • Electric shock • Lightning
Metabolic: • Diabetes:Is associated with two types of cataract. • 1)Senile cataract which appears earlier and may progress more rapidly. • 2)True diabetic cataract which is due to osmotic overhydration of the lens and appears as bilateral white punctate or snowflake posterior or anterior opacities.
Other causes of cataract - diabetes Juvenile Adult
Metabolic: • Galactosaemia – Oildropletcataract • Hypoglycaemia • Galactokinasedeficiency • Mannosidosis • Fabry’sdisease - angiokeratomacorporisdiffusum • Lowesyndrome – Posteriorlenticonus • Wilson disease – Sunflowercataract • Hypocalcaemia- tetaniccataract-parathyroiddestruction • Myotonicdystrophy – ‘Christmastree’ cataract
Toxic: • Corticosteroids • Chlorpromazine- (Largactil) sedative • Miotics • Busulphan - Myleran • Gold – Romatoid arthritis • Amiodarone
Corticosteroids: • Posterior subcapsular cataract • Safe dose? Children are more susceptible • Individual susceptibility (genetic?) • Less in intermittent therapy
Drugs Systemic or topical steroids Chlorpromazine - initially posterior subcapsular - central, anterior capsular granules Other drugs • Long-acting miotics • Amiodarone • Busulphan
Secondary: • Anterior uveitis: This is the most common cause of secondary cataract.The lens opacification seems to progress more rapidly in the presence of posterior synechia. • Hereditary retinal: Retinitis pigmentosa, Leber’s congenital amaurosis,Wagner’s and Stickler’s syndrome) • High myopia • Glaukomflecken – acute angle closure glaucoma
Glaucoma and Cataract • Glaukomflecken Acuteangleclosureglaucoma
Cataract and GlaucomaLens – Induced Glaucoma • PhacolyticGlaucoma mature /hypermaturecataracts: denatured lens protein leaksthroughintactcapsule, macrophagesingest lens protein , togethertheyclogthetrabecularmeshwork. • Lens ParticleGlaucoma Aftercataractsurgeryretainedcorticalmaterialparticlesobstructtrabecularmeshwork • PhacomorphicGlaucoma Intumescentcataractcausespupillaryblockandangleclosureglaucoma
Lens – Induced Glaucoma Signs & Symptoms: Headache Nausea Impaired general condition Red eye Pain in the eye Visual loss High intraocular pressure Middilated pupil with no reaction Shallow anterior chamber Leukocoria Treatment: • Systemic & Topical antiglaucomatous agents • Tranquilizers • Laser iridotomy • Cataract Surgery
Congenital CataractMaternal infections: • Rubella: Fetal infection is the direct result of maternal viraemia (which may be clinical or subclinical) with seeding of the virus in the plasenta. • Fetal infection is about 50% during the first 8 weeks,33% between week 9 and 12 and about 10% between 13 and 24. • Cataract, microphtalmos,retinopathy, glaucoma etc • Cataracts are present in about 50% of cases.After the gestastional age of 6 weeks the virus is incapable of transversing the lens capsule so that the lens is immune.
Maternal infections: • Altough the lens opacities (which may be unilateral or bilateral) are usually present at birth, they may occasionally develop several weeks or even months later. • The virus has been shown to be capable of persisting within the lens for up to 3 years postnatally.
Maternal drug ingestion: • Thalidomide • Corticosteroids
Leukocoria • literally means " white pupil « • Leukocoria can be caused by abnormalities in the lens (eg, cataract), vitreous (eg, hemorrhage), or retina (eg, retinoblastoma)
Causes of Leukocoria • Retinoblastoma • Persistent fetal vasculature • Retinopathy of prematurity • Cataract • Coloboma (fissure or cleft) of choroid or optic disc • Uveitis • Toxocariasis • Coats disease • Vitreous hemorrhage • Retinal dysplasia
Syndromes: • Down’s syndrome (mongolism) • Werner’ s syndrome • Rothmund’s syndrome
Hereditary • 1/3 of all congenital cataracts are hereditary and unassociated with any of the metabolic or sistemic disorders. • The mode of inheritance is usually dominant.
Morphological: • Capsular • Subcapsular • Nuclear • Cortical • Lamellar • Sutural
According to maturity • Immature:Scattered opacities are seperated by clear zones. • Mature: Cortex is totally opaque • Intumescent: The lens has become swollen by imbibed water.It can be mature or immature • Hypermature: Mature cataract which has become smaller and has a wrinkled capsule due to leakage of water out of lens. • Morgagnian: Hypermature cataract in which total liquefaction of the cortex has allowed the nucleus to sink inferiorly.
Classification according to maturity Immature Mature Hypermature Morgagnian
According to the age of onset • Congenital • Infantile • Juvenile • Presenile • Senile
Abnormalities of the lens shape: • Coloboma • Anterior lenticonus • Posterior lenticonus • Lentiglobus • Microphakia • Microspherophakia
Coloboma Ocular associations Coloboma of choroid Giant retinal tear Coloboma of iris
Lenticonus Posterior Anterior • Anterior axial bulge Central 3-4 mm of the lens • Posterior axial bulge • Unilateral - usually sporadic • Associated with Alport syndrome • Bilateral - familial or in Lowe • syndrome
LOWE SYNDROME Oculocerebrorenal syndrome Error of aminoacid metabolism X-linked inheritance pattern Frontal prominence and sunken eyes Proteinuria Fanconi syndrome Renal tubular acidosis Areflexia Muscular hypotonia Mental retardation Glaucoma Posterior polar cataract + lenticonus
ALPORT SYNDROME XLD inheritance Anterior lenticonus Pigmentary retinopathy Chronic renal failure Sensorineural deafness Hematuria
Small lens Microphakia Microspherophakia • Small diameter and spherical • Small diameter • Systemic association • - Lowe syndrome • May be familial (dominant) • Systemic association • - Weill-Marchesani syndrome
Ectopia lentis • Ectopia lentis is a displacement of the lens and may be congenital,developmental or acquired. • A subluxated lens is partially displaced from its normal position but remains in the pupillary area. • A luxated or dislocated lens is completely displaced from the pupil implying seperation of all zonular attachments.
Ectopia lentis • Findings associated with subluxation of the lens include decreased vision,marked astigmatism,monocular diplopia and iridonesis. • Potential complications of ectopia lentis include cataract and displacement of the lens into the anterior chamber or into the vitreous.
Ectopia lentis • Dislocation into the anterior chamber or pupil may cause pupillary block and angle –closure glaucoma.
Ectopia lentis • Inherited Marfan’s syndrome, Weill-Marchesani syndrome, Homocystinuria Hyperlysinaemia Familial ectopia lentis Aniridia
Marfan’ syndrome • Marfan’s syndrome is a heritable disorder with ocular,cardiac and skeletal manifestations. • From 50% to 80 % of patients with Marfan’s syndrome exhibit ectopia lentis. • The lens subluxation tends to be bilateral and symmetric and is usually superior and temporal.
Marfan’s syndrome • The zonuler attachments usually remain intact but become streched and elongated. • Associated ocular abnormalities in Marfan’s syndrome include axial myopia and increased risk of retinal detachment. • Children with lens subluxation may develop amblyopia if there is significant asymmetry in their refractive error or if their refractive error is uncorrected in early childhood.
Autosomal dominant Systemic features of Marfan syndrome • Arachnodactyly • Limb-trunk disproportion • Aortic dilatation, dissection • and regurgitation • Pectus excavatum • High-arched palate • Mitral valve prolapse
Ocular features of Marfan syndrome Lens Retinal detachment • Axial myopia • Lattice degeneration • Upward subluxation • Zonule usually intact Angle anomaly and glaucoma Cornea plana Blue sclera