Commentary: Techniques for removal of posteriorly dislocated lens fragment

Cataract surgery is one of the most commonly performed surgeries globally. It is estimated that nearly 10 million cataract surgeries are performed every year around the world.[1] The surgery has an extremely high success rate; however, it can be associated with a few complications. One of these complications include posterior dislocation of lens fragment. Various studies have found its incidence to vary between 0.3% and 1.3%, depending on the type of cataract and the surgeon’s experience.[2,3] Eyes with posterior dislocation of lens fragment can further be complicated by persistent uveitis, glaucoma, persistent corneal edema, macular edema, retinal detachment (RD), vitreous hemorrhage, etc.

The current gold standard of management for retained lens fragments is pars plana vitrectomy (PPV) with removal of the retained lens fragments. A thorough vitrectomy should be done. It must be ensured that there is no vitreous attached to the fragment or in the anterior chamber or the cataract wounds. The use of triamcinolone can help in better visualization of the vitreous. Posterior vitreous detachment can also be induced. However, we prefer to avoid this manoeuvre. Our group reported that none of the 90 eyes that underwent scleral-fixated intraocular lens (IOL) for nucleus drop developed RD.[4] Singh et al.[5] reported that the incidence of retinal breaks was higher in eyes that underwent posterior vitreous detachment (PVD) induction compared to those that did not in eyes with ectopia lentis.

The technique for the removal of the nucleus depends on its grade. However, it is always a good idea to inject a bubble of perfluorocarbon liquid (PFCL), big enough to cover the macula so as to prevent it from trauma. A soft nucleus can be removed with cutter alone, with a cut rate of 600–800 cuts per minute. We prefer to use momentary mode for lensectomy as it allows individual control of the aspiration and the cutting. This prevents frequent disengagements of the fragmentome from the cutter. The use of light pipe to crush the nucleus against the cutter probe makes the job easier, quicker, and safer. Several techniques have been described to manage a hard nucleus.

1. Phacofragmatome: The larger luminal diameter of a 20-G phacofragmatome (nearly four times than a 25-G vitrector) enhances the flow and followability of the nuclear material. Usually a 20/23-G hybrid vitrectomy is used with a high flow rate. We usually set the intraocular pressure at 40 mmHg.[6]

2. Illuminated endochopper: It has a blunt bent tip which can be used to divide the nucleus into smaller pieces and fixate the divided pieces, preventing them from falling back. However, the instruments must be handled carefully as the fragmentome may become damaged in case both the instruments come in contact with each other during fragmentation.[7]

3. Chandelier endoilluminator and sharp-tipped chopper: The suction of a phacofragmatome is used to grip the nucleus and a sharp chopper is used to divide it into multiple fragments that are then emulsified.[8]

4. Kebab technique: The tip of a bipolar pencil is placed close to the fragment and surface coagulation is applied when the tip of the pencil slightly touches the fragment till the tip becomes stuck to the center of the fragment. The fragment is then gently lifted away from the retina. The endoilluminator is used to adjust the position of the fragment and coagulation is re-applied till the tip of the bipolar pencil reaches the center of the fragment, making the bond stronger. The fragment is then lifted into the anterior chamber and emulsified with the phaco probe.[9]

5. Nitinol basket: Nitinol baskets have been successfully used to remove kidneys and salivary glands stones for several years. The nitinol stone extractor (NSE) is introduced into the vitreous cavity with the basket retracted in the guide catheter. The fragment is guided and engaged into the basket with the help of the light pipe or the vitrectomy probe. The basket is then slightly retracted and brought behind the iris plane. The fragment is then emulsified using a phacoultrasonic probe via a clear corneal incision.[10]

6. Sleeveless phaco tip-assisted levitation (SPAL) technique: A 20-G phaco needle from the sclerotomy. The lens fragment is aspirated and lifted to bring it into the mid-pupillary plane. The instrument in the non-dominant hand is used to guide the fragment above the iris plane into the anterior chamber. The fragment is then emulsified using the phaco probe.[11]

7. Delivering via the limbal route: The fragment can be elevated using active suction with the hard tip flute cannula/vitrector or a microvitreoretinal (MVR) blade and brought into the anterior chamber with the help of the instrument in the non-dominant hand.

We congratulate the authors for their study evaluating the predictive factors and visual outcomes after immediate PPV for posteriorly dislocated lens fragments during complicated phacoemulsification. The surgeons have used sulcus-fixated or iris-claw intraocular lens (IOL).[12] We would advise that scleral-fixated IOL be used in the absence of a sulcus.[4] While the timing of vitrectomy remains debatable—as studies have found that the results for immediate surgery are similar to delayed surgery—we prefer performing vitrectomy in the same sitting unless cornea clarity is poor. However, the surgery may be delayed in case of unavailability of a vitreoretinal setup.