cataract

السلام عليكم ورحمة الله

مبروك عليكم منتدى السنة الخامسه

والى الامام دائما

وحبيت انزل اول موضوع واهم موضوع في العيون




Shadi Awwad, MD
cataract
I. Classification
A. Morphologic
B. With respect to maturity
C. Age of onset
A. Morphologic:
1. Capsular Cataract
a. Anterior Capsular
-Congenital: from persistent pupillary membrane
-Acquired: Pseudoexfoliation syndromes, chlorpromazine, in association with posterior
synechiae
b. Posterior capsular:
-Congenital: in association with persistent hyaloid remnants (Mittendorf's dot)

2. Subcapsular Cataract
a. Posterior Subcapsular
-Complicated (e.g. in Diabetes Mellitis, Myotonic Dystrophy, steroids, irradiation)
-Age -related

Fig.1: Posterior Subcapsular Cataract )
Fig. 1: Annotated)

: Posterior Subcapsular Cataract (by retro illumination)
b. Anterior Subcapsular

-Acute angle closure glaucoma(Glaukomfleckens), amiodarone toxicity, miotics,
Wilson's disease

3. Nuclear Cataract
-Age-related
-Congenital: Rubella, Galactosemia
4. Cortical Cataract
-Usually spoke-like, can be anterior or posterior
-Can be congenital (very common)
-Usually doesn't interfere with vision
5. Lamellar Cataract
-Congenital. Involves one lamella of the fetal or nuclear zone
6. Sutural Cataract
-Congenital
-Very common
-Y-shaped opacity in the lens nucleus
-No clinical significance

B. Maturity

1. Immature Cataract
-scattered opacities are separated by clear areas
2. Mature
-Cortex is totally opaque


3. Intumescent
-The lens has become swollen by imbibed water
-Can be mature or immature
4. Hypermature Cataract
-Mature cataract that has become swollen and has a wrinkled capsule as a result of
leakage of water out of the lens.
5. Morgagnian Cataract:
-Hypermature cataract leading to total liquefaction of the cortex making the nucleus sink
inferiorly

C. Age of onset
1. Congenital
2. Infantile
3. Juvenile
4. Pre-senile
5. Senile

II. Etiology
A. Age-related
1. Sub-capsular
a. Anterior: due to fibrous metaplasia of the anterior lens epithelium
b. Posterior: just in front of the posterior capsule. It is associated with the posterior
migration of the anterior epithelium of the lens
-Patients with posterior sub-capsular cataract are more troubled than those with the
anterior ones, particularly from headlights of oncoming cars and bright sunlight.
-Near vision in these patients is also poorer than distance vision
2. Nuclear Cataract
-Exaggeration of the normal aging involving the lens nucleus (frequently preceded by
radial water clefts in the cortex.
-Often associated with myopia from the increase in the refractive index and increase
in the bi-convexity of lens. Some elderly patients with Nuclear Sclerosis may be able
to read again without their spectacles, due to the induced myopia: this explains the "second
sight of the aged".
B. Trauma can cause cataract: concussion, penetrating, electric shock or lightening.
C.. Metabolic
1. DM
-Senile cataract is accelerated
-True diabetic cataract: associated with over-hydration. Results in bilateral white punctate
or snowflake posterior or anterior sub-capsular opacities
2. Galactosemia, Glalactokinas deficiency, mannosidosis, hypocalcemic syndromes
(multifocal white flakes)
3. Toxic
-Steroids: systemic cause more cataract than topical. A dose <10mg/d or given for less than
one year is generally safe. Individual variability as well as dose and duration are all important.
Cause anterior and posterior sub-capsular lens opacities.
-Chlorpromazine: causes anterior lens capsule opacities
-Amiodarone: causes anterior sub-capsular opacities.
-Gold (used in Rheumatoid Arthritis): 50% have posterior lens opacities
-Miotics: cause anterior sub-capsular opacities
4. Secondary Cataract
-Chronic anterior uveitis
5. Miscellaneous
-Hereditary fundus dystrophy: Retinitis Pigmentosa, Leber's,..
-High Myopia
-Acute angle closure glaucoma (Glaukomfleckens): anterior capsular or sub-capsular
opacitiesin the pupillary zone
-Myotonic Dystrophy: Fine polychromatic granules in the cortex( "Blue-dot cataract"),
followed later by sub-capsular stellate opacities ("Christmas tree")
Fig. 6: Blue dot cataract)


-Atopic Dermatitis: bilateral anterior or posterior stellate opacities
-Down's syndrome
6. Intra-uterine
-Congenital Rubella: 15% of cases. After the 6th week, the virus is no more capable of crossing
the lens capsule.
-Toxoplasmosis
-CMV
-Maternal ingestion of Thalidomide, steroids,...
7. Hereditary
-Usually dominant
-Congenital to pre-senile

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