Crystalline lens diseases by Hatem G Ammar Assistant
Crystalline lens diseases by Hatem G Ammar Assistant Professor of Ophthalmology Sohag University
Anatomy
Biconvex, avascular, transparent structure enclosed by a capsule. The capsule is the basement membrane secreted by the lens epithelium. The capsule is thickest at the equatorial zone and thinnest at the posterior pole.
The lens epithelium is one layer that lines the ant capsule and the equatorial region(mitotic activity). The cells elongate and lose organelles to form the new lens fibres.
Anatomy
The central compact core is termed the nucleus, (hard). while the surrounding lens matter is the cortex, (soft)
Diameter: 9 -10 mm Thickness: 4 mm Weight: 60 mg-250 mg Refractive index: 1. 42 Dioptric power: 18 (inside), 70 D (outside? ? ? )
physiology Lens transparency? ? ? Lens functions.
Cataract = lens opacity
Classifications Aetiology n Age (soft ≤ 25 ys, hard >25 ys) n Site of opacity (capular and lenticular) n maturity n
Aetiologic Classification 1) Congenital 2) Acquired 1) Senile 2) Traumatic 3) Complicated (2 ry) 4) Drug induced 5) Radiation(uv, xray, infrared) 6) Deficiency (vit C&D) 7) Occupational
Senile (age related) cataract Morphological classification: 1) Subcapsular: Anterior Posterior 2) Nuclear 3) Cortical
Anterior subcapsular
Posterior subcapsular
Nuclear Cataract
Cortical Cataract
Classification according to maturity: 1) Immature. 2) Mature 3) Hypermature & Morgagnian
Mature cataract
Mature cataract
Hypermature cataract
Morgagnian cataract
Treatment of Senile Cataract 1) Non-surgical ? ? ? 2) Surgical: Indications: 1) Visual 2) Medical 3) Cosmetic ? ? ?
Surgical treatment # Preoperative evaluation. # Biometry: IOL power calculation # Intraocular Lenses: * Positioning: - PC IOL - AC IOL * Types: - Rigid - Foldable
Intraocular Lenses
# Anaesthesia: 1) General 2) Local : Retrobulbar Peribulbar Parabulbar (sub-Tenon) Topical Intracameral
# Types of surgery: 1) Extracapsular cataract extraction. 2) Intra capsular cataract extraction. 3) Phacoemulsification.
Extracapsular cataract extraction.
Extracapsular cataract extraction. (with ACIOL)
Phacoemulsification.
# Operative complications: 1) Complications of anesthesia 2) Rupture of posterior capsule 3) Posterior loss of lens fragments. 4) Posterior dislocation of IOL 5) Suprachoroidal hemorrhage.
# Postoperative complications: 1) Endophthalmitis. 2) Aftercataract 3) Corneal edema. 4) Iris prolapse 5) IOL malposition 6) RD 7) Cystoid macular edema
After Cataract
Definition: Etiology: 1) Cortical material 2) Inflammatory debris 3) Elsching pearls 4) Sommering 5) Capsular fibrosis
Elsching pearls
Capsular fibrosis
Treatment 1) Surgical 2) YAG laser
Congenital Cataract 1) Cataract without systemic association 2) Cataract with systemic association
Congenital Cataract 1) Cataract without systemic association 1) Zonular: affecting Discrete zone – Nuclear - Lamellar - Capsular - Sutural 2) Polar : anterior OR posterior 3) Others: Coronary – Blue dot – Total Membranous
Congenital Nuclear cataract
Congenital Lamellar cataract
Anterior Polar
Congenital Sutural cataract
Congenital Coronary cataract
Congenital Blue dot cataract
2) Cataract with systemic association 1) Metabolic: Galactosaemia 2) Prenatal infections: Congenital rubella 3) Chromosomal abnormalities: Down syndrome
Galactosaemia (oil droplet appearance)
Management of congenital cataract 1) Management of the eye (Ocular examination) 2) Management of the patient (Systemic investigations) 3) Management of the parents (Genetic analysis and serological tests)
1) Management of the eye (Ocular examination) 1) Density: the impact on vision - Very dense - Less dense - Visually insignificant 2) Morphology: a guide for the etiology 3) Associated ocular pathology: (EUGA) - Anterior segment - Posterior segment 4) Other indicators of visual impairment: Nystagmus – Squint 5) Special tests: VEP – Preferential looking
2) Management of the patient (Systemic investigations) 1) Examination by pediatrician 2) Serological tests (TORSH) 3) Urine analysis: Galactosemia
3) Management of the parents - Reassurance - Informations about the disease - Genetic analysis and serological tests
Timing for surgery According to laterality and density 1) Bilateral dense 2) Unilateral dense 3) Bilateral partially dense 4) Unilateral partially dense
Surgical techniques: 1) Lensectomy. 2) I/A. Management of the posterior capsule
Lensectomy
Visual rehabilitation: (Correction of aphakia) 1) Glasses 2) Contact lenses 3) IOLs 4) Occlusion (management of amblyopia)
Complicated (2 ry) Cataract
Complicated (2 ry) Cataract Causes: secondary to 1) Systemic diseases 2) Local (ocular) diseases
1) Complicated Cataract 2 ry to Systemic diseases: A) D. M: 1) Classical diabetic cataract 2) Age related cataract (earlier in D. M) B) Myotonic dystrophy Stellate posterior subcapsular cataract C) Atopic dermatitis D) Neurofibromatosis type 2 E) Hypocalcaemia F) Ankylostoma infestation
1) Complicated Cataract 2 ry to Ocular diseases: 1) Chronic uveitis 2) Glaucoma 3) High Myopia 4) Hereditary Fundus dystrophies e. g Retinitis pigmentosa
Complicated Cataract 2 ry to Chronic uveitis
Complicated Cataract 2 ry to Chronic uveitis
Drug induced cataract
Drug induced cataract: 1) Steroids - Systemic & local - Children more susceptible - Individual (Genetic) variation 2) Miotics 3) Iron & Gold 4) Chlorpromazine, Amiodaron & Allopurinol
Traumatic cataract
Traumatic cataract Causes: 1) Mechanical Trauma: - Penetrating trauma to the lens - Concussion (blunt) trauma: 1) Vossius ring 2) Rosette cataract 2) Electric shock 3) Ionizing radiation: in ocular tumors 4) Infra-red radiation: true exfoliation (What is pseudoexfoliation syndrome ? )
Vossius ring
Rosette cataract
Lens Subluxation & Dislocation
Definitions Lens Subluxation: partially displaced lens & still remaining in the pupillary area. Dislocation: completely dislocated rendering the pupil aphakic
Lens Subluxation
Posterior Dislocation
Etiology 1) Hereditary: A) Without systemic associations: - Familial ectopia lentis B) With systemic associations: - Marfan syndrome - Homocystinuria - Stickler syndrome 2) Acquired: - Trauma - Large eye: Myopia & Buphthalmos - Anterior uveal tumors - Hypermature cataract
Evaluation: Ocular & Systemic Management: 1) Observation 2) Surgical
Thank you
- Slides: 80