Lecture 3 CATARACTS. Classification of cataracts: By age: congenital, juvenile, age-related (senile) By location opacities in the lens as seen with slit beam : cortical, nuclear, anterior subcapsular, posterior subcapsular
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By age: congenital, juvenile, age-related (senile)
By location opacities in the lens as seen with slit beam: cortical, nuclear, anterior subcapsular, posterior subcapsular
By maturity: early, immature, mature, hypermature (Morgagnian cataract)
By pattern: cuneiform (typical senile type), zonular, polar, pyramidal (congenital types)
The same sign is progressive (not acute) painless visual loss
Aphakia is a condition of eye without lens. The visual acuity without correction is very poor – 0,02-0,04. Iridodenesis (iris vibration) is typical.
Thick plus glasses are needed for vision:
for far distance – sph convex 10,0-12,0 D
for near distance – sph convex 13,0-15,0 D.
Secondary cataract occurs eventually in about 20 % cases after cataract surgery. It is opacity of natural posterior capsule. It can be treated by YAG laser capsulotomy.
Attention! The term «complicated cataract»is used to describe a lens opacity which occurs as a result of some other disease of the eye. Longstanding uveitits, an untreated retinal detachment or an intraocular tumour are all examples of an associated disease.
I degree – visual acuity is 0,3 and more; the size of opacity is less then 1,5 mm; the surgery may be done at the age of 14-16 years.
II degree– visual acuity is 0,05-0,2; the surgery is usually done at the age of 3-4 years.
III degree– visual acuity is less then 0,05; the surgery must be done during first year of life.
Ectopia lentis (displacement of the lens) may be partial (subluxation) or complete (luxation).
Aethiology: trauma, familial ectopia lentis (may be associated with ectopic pupil), associated with other ocular disorders (aniridia and buphtalmos), Marfan’s and Weill-Marchesani syndromes, metabolic (homocystinuria and hyperlysinaemia).
Clinical features: iridodenesis (vibration of iris) and not proportional depth of anterior chamber.
Marfan’s syndrome: tall person with partial displacement of the lens (subluxation), fragile bones and arachnodactyly.