Pseudophakia
 

A posterior chamber lens showing  YAG capsulotomy. An anterior chamber lens in an eye with  complicated cataract operation showing  hazy cornea. This is pseudophakic  bullous keratopathy. An iris clip lens (Binkhorst lens). This  lens is not longer favoured due to the risk  of iritis, lens dislodgement and corneal  decompensation.

This patient has a cataract extraction with lens implant. The implant may be in the anterior chamber or posterior chamber. Iridectomy is performed for anterior chamber implant to prevent pupillary block. In the examination: state the type of operation performed for example corneal or limbal section; extracapsular cataract or phacoemulsification look for the reason for cataract operation operation for example anterior segment trauma, retinitis pigmentosa or Fuch's heterochromic cyclitis look for corneal decompensation especially with an anterior chamber lens

Questions:

1. What are the advantages of capsulorrhexis over capsulotomy?

Answer
Capsulorrhexis provides a stronger edge and allows phacoemulsification to be carried out safely. In addition, an implant can be held more securely and gives a better centration.

2. During the operation, you rupture the posterior capsule. You place the lens in the sulcus instead of the capsular bag. What would happen to the post-operative refraction from what you have anticipated?

Answer
Ideally, if the lens were to be placed in the sulcus, the power of the lens (with the same A constant) is reduced by 1/2 D from that calculated pre-operatively. Otherwise, the focal point is moved anteriorly and the patient becomes myopic.

3. When would you expect cystoid macular oedema following cataract operation?

Answer
Cystoid macular oedema following cataract operation is also termed Irvine-Gass syndrome. It is typically seen 4 to 8 weeks following the cataract operation.
It is more common after intracapsular than extracapsular cataract extraction. It is also increased in vitreous loss or in the presence of iris or vitreous incarceration.
Treatment is controversial as a great majority improves without treatment. Treatment options include topical steroid or non-steroidal anti-inflammatory medications. Acetazolamide is often given and is believed to reduce the macular oedema. In the presence of predisposing factors such as iris or vitreous incarceration, freeing the iris and vitrectomy can improve the oedema.

 
 

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