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Hard brown cataracts can be managed using phaco
A phaco chop technique can master these difficult cases.
Phacoemulsification in hard brown cataracts is a difficult proposition. The problems are plenty: the capsulorrhexis is difficult to perform; cracking is difficult; the posterior capsule may be weak, and slight pressure can result in a dropped nucleus; and chopping is quite tough.
The advantages of phacoemulsification are lost if one has a complication such as posterior capsular rupture or a dropped nucleus. If the surgeon is not an expert in phaco, it is better to perform extracapsular cataract extraction (ECCE) in such mature brown cataracts. A good ECCE is better than a bad phacoemulsification.
We have developed techniques for performing phaco successfully in these difficult cases. This article outlines our suggestions.
Temporal site preferred
| The left hand injects viscoelastic using a 26-gauge needle. Fig. 1 |
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We prefer to perform a temporal clear corneal incision. If the astigmatism is plus at 90°, then the incision is made superiorly. First, a needle with viscoelastic is injected into the eye in the area where the second incision is made (Figure 1). This will distend the eye so that when the clear corneal incision is made, the eye will be tense and one can create a good valve. A straight rod is used to stabilize the eye with the left hand. With the right hand, the clear corneal incision is made (Figure 2).
A capsulorrhexis is performed through the same incision (Figure 3). In mature brown cataracts, it is difficult to visualize the rhexis. One should be careful when one is performing this maneuver, for if one loses the rhexis, one should convert the case rather than continue with phaco. Other methods by which rhexis can be done safely in hard brown cataracts include staining the capsule or using an endoilluminator in the other hand. Generally, it is easier to perform the rhexis with forceps rather than a needle in such cases, as visualization is very tough.
Hydrodissection is then performed. One will not be able to see the fluid wave, as the cataract is very dense. Watch to see if the lens comes up anteriorly a little bit. This will indicate that hydrodissection is complete. One also can test this by rotating the nucleus before starting phaco.
Embedding the nucleus
We insert the phaco probe through the incision slightly superior to the center of the nucleus. At that point, ultrasound is applied and we observe to ensure the phaco tip gets embedded in the nucleus (Figure 4). The direction of the phaco probe should be obliquely downward toward the vitreous and not horizontal toward the iris. Only then will the nucleus become embedded. The settings at this stage are 80% phaco power, 24 mL/minute flow rate and 101 mm Hg suction.
By the time the phaco tip gets embedded into the nucleus, the tip has reached the middle of the nucleus. We do not turn the bevel of the phaco tip downward when we do this step, as the embedding is better the other way. We prefer a 15° tip, but any tip can be used.
Note that in Figure 4 the phaco tip is fully embedded in the nucleus. Then we stop ultrasound and bring the foot switch to position 2 so that only suction is being used. With the chopper, we cut the nucleus with a straight downward motion (Figure 5) and then move the chopper to the left when we reach the center of the nucleus. In other words, the left hand moves the chopper like an inverted L. Do not go to the periphery for chopping, but do it at the center.
Once we have created a crack, we split the nucleus to its center. We then rotate the nucleus 180° and crack again so that we have two halves. In hard brown cataracts, the nucleus will crack but sometimes in the center the nucleus will still be attached. The surgeon has to split the nucleus totally into two halves and should see the posterior capsule throughout (Figure 6).
Further division
Now that we have two nuclear halves, we have a shelf to embed the probe. We place the probe with ultrasound into one half of the nucleus (Figure 7). Note that in Figure 7, the phaco tip is embedded into the nucleus. We embed the probe, then pull it a little bit (Figure 8). This step is important so that you get the extra bit of space for chopping. This prevents the surgeon from chopping the rhexis margin. We apply the force of the chopper downward (Figure 9). We then move the chopper to the left so that the nucleus is split (Figure 10). Again, we observe the posterior capsule throughout so that we know the nucleus is totally split. We then release the probe (Figure 11), as the probe is still embedded into the nucleus. In this manner, we create three segments in one half of the nucleus. We then make another three segments in the other half of the nucleus. Thus we now have six segments or pie-shaped fragments. The settings at this stage are 70% phaco power, 24 mL/minute flow rate and 101 mm Hg suction.
Remember five words: embed, pull, chop, split and release.
Once all the pieces have been chopped, we remove each piece one by one and, in pulse phaco mode (Figure 12), aspirate the pieces at the level of the iris. We do not work in the bag unless the cornea is bad preoperatively or the patient is very elderly. The settings at this stage can be phaco power 50%, flow rate 24 mL/minute and suction 101 mm Hg.
The next step is to do cortical clean up (Figure 13). We always try to remove the subincisional cortex first, as that is the most difficult. Note that at all times, the left hand holds the straight rod, therefore controlling the movements of the eye. If necessary, we use a bimanual irrigation/aspiration technique. We then inject viscoelastic and implant a plate haptic foldable IOL (Figure 14) with large fenestrations. At the end of the procedure, we inject the balanced salt solution inside the lip of the clear corneal incision. This creates stromal hydration at the wound. This causes a whiteness that disappears after 4 to 5 hours. The advantage of this is that the wound seals better.