Anterior Capsulotomy

Fig. 6.1
This shows lens iris capture superiorly (white arrows); this occurred because the anterior capsulorhexis diameter was larger than that of the optic of the intraocular lens. In these circumstances the anterior capsule edge and the posterior capsule fuse (short white arrows) and push the lens forward. When the child rubs his/or her eyes this causes trampolining of the anterior chamber and the lens can move forward also, causing lens iris capture (long yellow arrow showing iris behind optic edge, white arrows). This can also be seen if an implant is placed in the sulcus

6.2 Anterior Capsulotomy Techniques

There are several techniques that have been employed to perform anterior capsulotomy in children. They include

  • Vitrectorhexis

  • Diathermy

  • Plasma blade

  • Traditional Manual capsulorhexis

  • Foldable template ring

  • Two Incision push-pull (TIPP) rhexis

  • Femtosecond laser

6.2.1 Vitrectorhexis

In this technique a low aspiration high cut rate is employed to construct an anterior capsular opening. The vitrector port can be employed face down so that the initial cut is employed to break into the capsule and then a smooth circular motion employed to complete the opening. Alternatively after the initial cut is made the port is turned up and the opening made in exactly the same way but now the surgeon has a view of where the cut is being made. A venturi pump is best for this technique because a peristaltic pump relies on occlusion of the port to develop aspiration vacuum, which of course is only momentary given how thin the capsule is. The author preferentially uses this technique when no implant is being used (Fig. 6.2). The reason for this is that there is good evidence that the rhexis edge produced by this method is not as robust as a manual tear [2]. Comparison of mechanized anterior capsulectomy and manual CCC in vitro (18 pairs of postmortem eyes aged 4 days to 16 years) where one eye of each pair had vitrectorhexis, and the other eye manual tear resulted in a radial tear in one of 18 eyes (16 year old eye) with vitrectorhexis but none in the eyes with manual tear.


Fig. 6.2
This shows the vitrectorhexis technique. Here there is an anterior chamber maintainer being used and the port of the vitrector has been turned up after breaching the capsule and passing the vitrector under the anterior capsule through the initial breach. A circular motion is used to achieve a round rhexis

However, in six eyes (all under 5 years of age), the manual tear could not be successfully continued or completed [3].

Subsequently, a study comparing anterior vitrectorhexis and manual tear in pediatric cataract surgery showed that 19 of 339 eyes (5.6 %) had an anterior capsule tear (in vitrectorhexis group, 12 of 226 eyes (5.3%) and in the manual tear group, 7 of and eyes (6.2%). This study concluded that vitrectorhexis was appropriate for use in children under the age of 6 years [4]. This author’s experience is that the younger the child (especially under the age of 1 year) the more robust the vitrectorhexis edge and the more reliable its use when implanting IOLs. If an IOL is not being implanted it is the technique of choice.

Recently authors have described the use of a 23G system to perform the anterior capsulotomy [5]. These authors implanted nine eyes and reported no capsular tears. Theoretically a smaller gauge may well result in a more robust rhexis edge but no studies have looked at this using the 23G system.

6.2.2 Radiofrequency Diathermy

Capsulotomy using radiofrequency diathermy was originally described by Kloti in 1984 [6] and further explored by Gassmann et al. in 1988 [7]. Comer et al. [8] described its use in pediatric cataract surgery for both the anterior and posterior capsule and reported no complications. The use of radiofrequency diathermy, however, has become less and less favorable because the technique predisposes to a higher rate of tags and tears. The idea is to use a diathermy tip to score out the rhexis and then remove the central area. The problem is that when the capsule is removed there are often tags left behind and again the rhexis edge is not as robust as a manual tear.

6.2.3 Plasma Blade

The plasma blade (also known as the Fugo blade after the inventor) uses pulses of plasma that are generated around its tip to cut and cauterize tissue. The resulting rhexis edge appears to be robust [9]. The advantage of this technique is that it can be used to create an anterior capsulotomy through fibrous tissue e.g. in a traumatic cataract and also other anterior capsular plaques where traditional manual tearing may not be successful. However experience with the plasma blade in pediatric ophthalmology is limited.

6.2.4 Traditional Manual Capsulorhexis

The traditional manual capsulorhexis technique is by far the most popular in the world, mainly because individuals who perform adult cataracts as well as pediatric cataracts perform the majority of the world’s pediatric cataracts [10, 11]. The transition from the adult capsule to the pediatric capsule has a definite learning curve. Using a capsulotomy needle is possible but more difficult than using a capsulorhexis forceps. The younger the child, the more elastic the capsule and the more there is curvature of the anterior lens capsule. To counter these two findings, a heavy viscoelastic should be used to hyper inflate the anterior chamber and so flatten the anterior capsule as much as possible Fig. 6.3a). In this way while the capsule may be elastic the surgeon now longer has to worry about the tear running away down the anterior curvature of the lens (see Fig. 6.3a, b, c). The next trick is to starts in the center of the putative rhexis need and makes short tears and re-grasp at the root of the tear so as to have maximum control. It is best to spiral the tear until the desired size is needed. In Fig. 6.3d, The tear is started centrally (#1) and then regrasped for segment #2, and again for segments #3, #4 and #5 and each segment spirals out until the desired size is reached and the rhexis completed by segment #6. Each time the flap is re-grasped it is important to pull to the center of the capsule, as the elasticity of the capsule will give the curvilinear edge desired. If this is not done the edge will tend to tear out and the capsulorhexis will become bigger and bigger. The downside of this technique is that it takes a little while to get used to getting a consistent sized capsulorhexis.


Fig. 6.3
This schematic shows a technique for manual capsulorhexis in children. (a) shows that if the anterior chamber is NOT hyper inflated the anterior curvature of the child’s eye and the elasticity of the child’s capsule can cause the tear to run away towards the equator (long black curved arrow). This is shown in (b) also. In this figure the dotted circle is the target capsulorhexis. The pink curved arrow shows where the rhexis was initiated (in the center of the capsule) and the yellow shaded area is the flap. The dark green is the exposed lens material. The straight arrow shows that the tear is running away towards the equator because of the situation shown in (a). When the anterior chamber is hyper-inflated, (c), control of the rhexis is easier (long curved black arrow shows tear is not running to the equator) but the elasticity of capsule must be tackled. One way to do this, is to use a spiraling technique shown in (d). The tear is started centrally (1) and then regrasped for segment 2, and again for segments 3, 4 and 5 and each segment spirals out until the desired size is reached and the rhexis completed by segment 6. Each time the flap is re-grasped it is important to pull to the center of the capsule, as the elasticity of the capsule will give the curvilinear edge desired

The use of trypan blue to stain the capsule and so be able to see the capsule when there is complete white lens opacity has been shown to immediately physically reduce the elasticity of the human lens capsule after application. This in turn makes the pediatric capsule more stiff and less elastic [12].

6.2.5 Foldable Template Intraocular Ring

One method of ensuring extremely accurately the size of the capsulorhexis has been employed by Tassignon for the use of her ‘Bag-in-the-Lens IOL’ which demands a very accurate sizing of both the anterior and posterior rhexis. A compressible intraocular ring [13, 14] is placed on the anterior capsule and then the anterior chamber hyper inflated. The rhexis is started centrally again, as described above, but now there is a barrier to prevent the rhexis getting larger or running out. Once the rhexis is completed the ring is removed.

6.2.6 The Two Incision Push Pull Rhexis (T.I.P.P. Rhexis)

Nischal first described this technique in 2002 [15]. The technique entails two stabs being made using an MVR blade, after the anterior chamber has been inflated with a viscoelastic. In this technique it is better not to hyper inflate the eye because the curvature of the anterior lens actually helps to make the rhexis more round. The technique differs depending on the age of the child.

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Nov 21, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Anterior Capsulotomy

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