VSR 421: Regional Veterinary Surgery (2+1)

TREATMENT

Discission or Needling

• The anterior capsule of the lens is incised in a cruciate fashion, using a cataract needle so that the aqueous humour will come in contact with the lens substance and will facilitate re – absorption of the opacity.
• Discission will have to be repeated periodically to obtain the desired effect. It may not be effective in all cases.

Couching of the lens

• The lens is pushed downwards and backwards by introducing a proper instrument through an incision in the cornea. Couching of the lens is not a practicable treatment in veterinary practice because the suspensory ligament of the lens in animals is very strong.
• In man, dissolution of the opaque lens by using 0.02% trypsine has been reported.

Removal of the lens

 

Intra ocular set

• It is occasionally done in the dog. The removal of the lens in the dog is more difficult than in man because the lens of the dog is proportionately much larger, and the suspensory ligament of the lens is tough.
• Removal of the lens will not serve any purpose if there are degenerative changes in the retina associated with cataract. In estimating the prospects of the operation the existence of pupiliary reflex is of some help.
• There are two methods for removal of the lens, viz., the intracapsular extraction, and the extracapsular extraction.
• Intracapsular extraction is the extraction of the lens with its capsule. This is difficult in animals because of the tough suspensory ligament.
• Extracapsular extraction is the extraction of the lens without its capsule. The anterior capsule of the lens is incised and through that the lens substance is removed.
• Extracapsular extraction is successful only if the cataracts is ripe (mature). At this stage the endothelial cells of the capsule that are left behind are incapable of proliferating. Whereas, if the operation is done before fully ripe, the proliferation of the endothelial cells after surgery may once again create opacity and this will interfere with vision.
• Extracapsular extraction of the lens is difficult if the cataract is hyper – mature because of the partial liquefaction or softening of the lens substance.
• ECCE +IOL ( Extra capsular catarct extraction + Intra ocular lens)
• Extracapsular cataract extraction is an operation in which the lens nucleus and cortex, excluding the capsule, are delivered through a corneal incision involving about one-half of the circumferences of the cornea, with rigid lens implantation .

Phacoemulsification unit with hand piece