As cataract surgeons, we have all experienced vitreous loss at some point in our careers. When this intraoperative complication occurs, it is important to take the appropriate steps to ensure the patient has the best possible outcome. The accompanying video demonstrates how to perform an anterior vitrectomy and cortex removal after a posterior capsular hole with vitreous prolapse has occurred.
This was a routine phacoemulsification case in which I noticed a hole in the posterior capsule when I was preparing for cortical cleanup with irrigation/aspiration (I/A). The hole was most likely caused by the phaco needle during nucleus removal, but it was not identified until the I/A probe was inserted into the eye.
When a posterior capsular tear is present, the first step is to keep the eye pressurized to prevent collapse of the anterior chamber. This is achieved by keeping the phaco or I/A handpiece in the eye and continuing to irrigate until an ophthalmic viscoelastic device (OVD) is injected into the anterior chamber to maintain space. Otherwise, the vitreous will move forward and an intact vitreous face will usually rupture causing vitreous prolapse. In addition, a small posterior capsular tear can extend to become a much larger one. This principle of maintaining adequate pressure in the anterior segment must be followed throughout the rest of the procedure (i.e., OVD must be injected prior to removing the irrigating instrument).
When performing an anterior vitrectomy, the other key principles are to separate infusion from cutting so as not to hydrate the vitreous; to cut from below to draw the vitreous into the posterior segment rather than into the anterior chamber; and to use a high cut rate. If there is a large posterior capsular tear with vitreous loss, then I prefer to perform the AV through the pars plana 3mm posterior to the limbus.
In this video, the posterior capsular defect was a small hole with minimal vitreous prolapse, so I elected to use a bimanual AV approach through self-sealing corneal side port incisions placing the irrigation cannula in the anterior chamber and the vitrector through the posterior capsular hole into the anterior vitreous after the prolapsing vitreous strands had been cut and aspirated. The proper vitrectomy settings on the phaco machine are a high cut rate and the cut/IA mode in order to minimize/prevent vitreous traction (a major risk factor for a retinal tear) during removal. Older phaco units had a maximum cut rate of 600/min, but the newer devices have ultra-high speed cut rates (i.e., 2500 cuts/min for AMO WhiteStar Signature, 4000 cpm for Alcon Centurion, and 5000 cpm for B+L Stellaris).
I was able to visualize the vitreous throughout this case; however, if the prolapsing vitreous cannot be seen clearly, then it is helpful to inject intracameral preservative free triamcinolone (i.e., Kenalog, Triesence), which adheres to and “stains” the vitreous white. Once the vitreous has been removed from above the capsular plane, the vitrectomy mode can be changed from cut/IA to IA/cut so that the remaining cortex can be removed from the capsular bag in a similar fashion to using a standard I/A handpiece. The bimanual technique allows easy access to all quadrants of the capsular bag, and using the vitrector in this fashion makes it very easy to remove any additional vitreous that may prolapse anteriorly without having to change instruments.
After the anterior segment is free of vitreous, the intraocular lens must be inserted in a stable position. In this case, the posterior capsule was intact except for a focal round hole that was not at risk for tearing or extending. Therefore, I placed a posterior chamber implant in to the capsular bag. Care must be taken during the lens implantation and subsequent OVD removal steps to ensure that vitreous prolapse does not recur. An effective method for detecting small strands of vitreous in the anterior chamber at this point during the procedure is to inject an intracameral miotic (Miochol or Miostat) to constrict the pupil and then inspect its shape. The pupil should become small and round. A tented area or irregular pupil margin is a sign that a vitreous strand is present. This can be severed with a vitrector or scissors; I prefer to use micro-scissors placed through a vitreous free side port incision.
Because vitreous loss is a risk factor for postoperative endophthalmitis and cystoid macular edema, I administer a subconjunctival injection of both antibiotic and steroid at the conclusion of such cases. I also have the patient continue topical steroid and NSAID eye drops for eight weeks after surgery.