There are cases where a patient has both anterior and posterior segment pathology and doing both a cataract surgery plus a pars plana vitrectomy is required for best visual results. Some surgeons are trained in both anterior and posterior segment surgery and are comfortable doing both at the same sitting. Other surgeons, like me, specialize in just anterior segment surgery so a combined case is done with a second surgeon who specializes in vitreo-retinal surgery.
The cataract and pars plana vitrectomy can be done at the same sitting, typically with the cataract surgery being done first. This allows the vitreo-retinal surgeon a better view for performing delicate procedures such as peeling a macular membrane. But we must tailor our cataract surgery to make it more compatible with the retinal procedure.
A few key points to consider:
- Create a strong incision that seals well so that it does not leak during the pars plana vitrectomy. If there is any doubt as to the integrity of the incision, place a suture to close it.
- Overlap the optic with the capsulorhexis for a full 360 degrees and aim for a somewhat smaller diameter of about 4.5 to 5 mm to ensure that the IOL will not inadvertently come out of the capsular bag if there is shallowing of the anterior chamber or pressure from a gas bubble placed in the vitreous cavity
- Choose an appropriate IOL and this typically means a monofocal IOL (of course, toric monofocal IOLs are acceptable as well). Avoid diffractive IOLs such as multi-focal and extended depth of field IOLs since these may impede the view of the retina and patients may not realize the full benefit of these IOLs if they have macular disease. Hydro-phobic acrylic IOLs are a good choice since the material is compatible with retinal surgery including possible use of silicone oil.
- Keep the cornea clear by minimizing the surgical trauma. This means keeping the total phaco energy low by use of chopping and phaco power modulations. Also minimize the total surgical for the cataract procedure and keep the amount of balanced salt solution that runs through the eye to a minimum.
- Adjust the IOL calculations to ensure that the patient ends up slightly myopic instead of slightly hyperopic. I will sometimes add +0.5 diopters to the calculated IOL power since I anticipate that the optic will sit just a bit more posterior due to the lack of vitreous.
Click below to see me adjust cataract surgery in preparation for a pars plana vitrectomy:
From: Christian Sanfilippo MD (via Facebook)
Great case! A couple comments: Some advocate for the use of a three piece lens in cases where gas or air will be necessary for theoretical better stability. Second, in my experience, these patients tend to have more inflammation than when either procedure is done separately, so more frequent topical steroid may be necessary postoperatively. This is especially true in patients undergoing vitrectomy for advanced diabetic retinopathy.