Fig. 38.1 Decision-making tree about the lens in the eyes undergoing VR surgery. See the text for more details

•Do not make the capsulorhexis larger than ~5 mm.

•Occasionally2 it is best to keep the visco in the AC until the PPV has been completed.

•Always perform a posterior capsulectomy after the IOL has been implanted.

38.2Lensectomy

If the surgeon knows that the lens capsules must also be removed (see below), the pars plana lensectomy approach offers familiarity in technique and access.3 PPL is very effective as long as the lens material is soft4; otherwise, the probe will be able to remove the cortex but little of the nucleus.

2Such as shallow AC, floppy iris, constricting pupil, VH seeping anteriorly, silicone oil prolapsing.

3Use of the probe and entering the eye through the cannula, respectively.

4The cut-off age is ~55–60 years, but a lot of other factors (such as the intraocular pathologies and the type of equipment) also play a role.

38.2.1 Lens In Situ

•Always use the superotemporal sclerotomy for access.

Q&A

Q Why not use the superonasal sclerotomy for lens in situ PPL or phacofragmentation?

A The probe must be held horizontally, which is impossible if the nose is in the way. The surgeon should use a finger of his other hand to securely keep the probe in position (see Fig. 2.1).

•Insert a 23 g needle and slice the capsule open at the equator. The goal is to provide a resistance-free entrance into the lens for the blunt probe.5

•Push the probe into the lens. Turn the port sideways to avoid biting into either capsules.

•A soft lens requires aspiration only; the cutting function needs to be activated only if the lens nucleus is hard or the material obstructs the outflow.6

•It is very difficult to avoid injuring the posterior capsule. Small lens particles are likely to fall posteriorly, but they can easily be removed during the subsequent vitrectomy.

Pearl

The posterior capsule is virtually impossible to preserve during PPL. The infusion is not directly inflating the capsular bag, which therefore starts to collapse during lens removal and progressively moves closer and closer to the probe’s tip. This, unlike the distance between the anterior capsule and the port, cannot be monitored.

•Aspirate the cortical material as if during standard phaco surgery.

•Decide whether the anterior capsule7 needs to be retained (see below, Sect. 38.6). If yes, it must be thoroughly polished.

5The probe would otherwise tend to push the lens away, putting undue stress on the zonules.

6This will occur much more often than during phaco since the internal lumen of the probe is much smaller.

7And the remnant of the posterior capsule.

38.2.2 Lens in the Vitreous8

•Complete the vitrectomy first, including the creation of a PVD.

•Change the settings on the machine: lower the cut rate to 100–300 cps and increase the aspiration/flow as needed.9

–If the cut rate is high and the lens material is hard, occlusion of the port becomes impossible and the lens fragment will keep being pushed away.

•Soft material10 is easy to remove.

•If the nucleus is hard,11 utilizing the light pipe as a “crusher” may obviate the need for ultrasound.

–Using aspiration only and with the port turned toward the retina, lift the piece into the midvitreous cavity, at a safe distance from the retina.

–Do not take your foot off the pedal; continue aspirating so that the piece does not fall back.

–Turn the probe 180° so that it is now underneath the lens particle.

–Use the light pipe to “force-feed” the lens material into the port (see Fig. 38.2). The particles may time-to-time clog the probe, requiring the nurse to flush it.

–Repeat the entire sequence until all pieces are removed.

–Alternatively, after you brought the hard piece into the midvitreous cavity, hold it there so that you can view it with the BIOM switched out, and exchange the light pipe for a forceps. Grab the piece so that its smallest dimension can be turned toward the probe, and feed it into the port.

•After all visible lens particles are gone, irrigate the vitreous cavity to bring into view and remove any previously hidden or miniscule, circulating pieces; these would increase the postoperative inflammation.

38.3Phacofragmentation12

The indications to use a pars plana approach to remove the lens are similar to those listed under PPL (see above), as is the rule to utilize the temporal sclerotomy for lens removal.

Adjust the pedal function to operating the machine in phacofragmentation mode.13

8Luxation in toto or lens particles lost during in situ PPL. Lens subluxation is discussed in

Sect. 63.6.

9This is why the vitreous must be removed first; otherwise, VR traction is unavoidable.

10Cortex; nucleus in young people.

11Ultrasound may be required (see below, Sect. 38.3).

12Ultrasound is necessary when a nucleus is too hard for the probe, and even crushing does not work.

13My setup is similar to that used in vitreous removal: the initial pressing down with the pedal results in aspiration/flow; further pressing will activate the ultrasound (turning of the foot not required, see Sect. 16.3).

L

R

LP

Fig. 38.2 Schematic representation of removing hard lens particles from the vitreous cavity. (a) The probe (P) is able to bite into the lens particle (L) only if it can attack it from the smallest dimension of the particle; however, this may be dangerous because the tip of the probe can be pushed into the retina (R). (b) It is easy to engage the particle from above (left hand side), but this does not allow any bite into the particle since the material is hard and the surface area too large. In addition, the high aspiration rate makes cutting in this position risky. On the right hand side, the cutter is unable to engage the tissue, whether it is the lens or a sheet of vitreous over the retina, because there is no edge. (c) Picking up the particle and bringing it away from the retina increase safety. The probe is rotated so that the port now faces the surgeon; the lens particle is not lost because the (high) aspiration/flow is maintained. However, the probe still cannot bite into the particle because it is hard and the area of contact is too large. (d) The light pipe (LP) is able to push the particle into the port. The particle is either gradually eaten (at a low cpm rate) or, more commonly, broken into smaller pieces. The pieces must have at least one side that is small enough to be fed into the port

38.3.1 Lens In Situ

•Place the cannula for the infusion and for the temporal working sclerotomy14 first; whether the superonasal cannula is also inserted now or later is up to you.

•Do a judicious anterior vitrectomy.15

14If you are using a machine (such as the EVA by DORC, Zuidland, the Netherlands) that allows

23g phacofragmentation; if only a 20 g phacofragmentor can be used, it is best to use a separate incision for it and then suture this sclerotomy before the vitrectomy is completed.

15It may be impossible to preoperatively recognize that the posterior capsule is broken; it is very difficult to recognize intraoperatively that vitreous has prolapsed into the lens. The risk is aspirating anterior vitreous and exerting traction on the retinal periphery (see Sect. 63.6).