Three key points to consider when you perform cataract surgery in an eye with prior pars plana vitrectomy:
- Check the Capsule: Make sure that there is no iatrogenic trauma to the lens capsule from the prior pars plana vitrectomy. If there is a suspicion of posterior capsule compromise, be very careful because if this extends the entire lens nucleus will fall posteriorly deep into the vitreous cavity. And since there is no vitreous present, it will sink very rapidly.
- Avoid posterior pressure: The cataract is only supported by the zonular apparatus because the anterior hyaloid face is gone. There is no central support of the lens nucleus and thus it can trampoline up and down. Avoid high infusion pressures and do not exert downward force during nucleus removal. In the video here, a horizontal chop is used to divide the nucleus into halves which are then brought up to the iris plane for aspiration.
- Increase the IOL power: Since the vitreous is gone, you can expect the IOL to sit a little deeper inside the eye. For this reason, I like to add +0.5 D to the IOL power which was calculated so that we err on the side of mild myopia and avoid hyperopia.
The result for this patient was excellent, with a near plano refraction, clear cornea, and well-positioning IOL. This patient had the prior vitrectomy for a peeling of an epi-retinal membrane. To help prevent cystoid macular edema, she will be using topical NSAIDs and then following up with her retinal specialist.
Click below for my technique of cataract surgery after prior pars plana vitrectomy
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