Australian Journal of Ophthalmology 1984; 12: 91-93

EXTRACAPSULAR CATARACT EXTRACTION

George Thomson FRACO Departments of Ophthalmology, Lidcombe and Westmead Hospitals, Sydney

Ophthalmologists are aware of the revival of the popularity of extracapsular cataract extraction (ECCE). The principal reasons ‘for this are: (i) technical advances made in instrumentation and operating microscopes which have greatly increased the precision of surgery; (ii) the advan- tages of ECCE, in particular the reduction of cystoid macular oedema, corneal decompensa- tion and retinal detachment, which are obviously related to preservation of the posterior capsule; and (iii) the marked superiority of iridocapsular- supported intraocular lenses, especially the new generation posterior chamber lenses.

All trainee ophthalmologists are now taught ECCE, but those of us who finished our formal training prior to this revolution have trained almost exclusively in intracapsular cataract extraction (ICCE).

It was with considerable difficulty that I con- verted to ECCE and my resolution to convert frequently wavered when I reflected on the ease and speed of ICCE. However, I persisted and the surgical results have certainly been very satisfying. I hope that this paper will assist those of you who are having similar doubts to those I was experiencing.

BASIC REQUIREMENTS You must have a microscope with a coaxial light to be able to visualise the red reflex and the posterior capsule.

You need a widely dilated pupil. 1 find 10% phenylephrine alternating with tropicamide (Mydriacyl) 1% every 15 minutes, starting one hour preoperatively, effective.

There are three new steps an intracapsular surgeon must learn to be a successful extra- capsular surgeon: (i) removal of the anterior capsule; (ii) removal of the nucleus; and (iii) removal of the cortex.

Removal of the Anterior Capsule The aim is to remove the central anterior capsule and expose the nucleus and cortex.

The preferred method is to cut the capsule in- to a trapdoor hinged at the upper pole of the lens. An irrigating cystotome is fashioned from a 26 gauge needle-care should be taken not to blunt the cutting end or the capsular cuts may be irregular. This is then passed into the anterior chamber through a paracentesis in the peripheral cornea at about 10 o’clock. It is attached to the irrigating line which is carefully cleared of air bubbles, which would distort the operator’s view of the anterior capsule if they reached the anterior chamber. The flow is adjusted to be sufficient to maintain the anterior chamber.

A series of radial cuts is made in the peripheral capsule commencing at 6 o’clock and proceeding to 2 and 10 o’clock respectively. The cuts commence peripherally and are extended centrally. When this is complete the capsule is

Reprint requests: Dr G. Thomson, 1 7 1 Hawkesbury Road, Westmead, New South Wales 2145.

91 EXTRACAPSULAR CATARACT EXTRACTION

Figure 1.

peeled from 6 o’clock to the upper pole of the lens.

Problems 1. Small pupil. If a small immobile pupil is encountered the cataract section is completed, and a peripheral iridectomy is cut and then extended into a keyhole iridectomy.

The anterior capsule is then sufficiently exposed to do the capsulotomy as previously described. Care must be taken to maintain the anterior chamber by increasing the irrigation flow or by using Healon@.

After the ECCE is complete the keyhole iridectomy may be left o r repaired with a 10.0 prolene suture. 2. Hypermature lens. As soon as the anterior capsule is punctured the anterior chamber is filled with fluffy lens matter and the surgeon’s view of the capsule is obscured. This means that the capsulotomy must be executed quickly. I find the method shown in (Figure 1) effective-the capsule is cut by three sweeps of the irrigating cystotome. 3. Tags of capsule remain. These only cause concern if they obscure the visual axis.

If the pedicle of the capsule is thin a firm pull should detach it-‘toilet tissue manoeuvre’.

If the pedicle is broad traction will result in a dialysis so the tag must be cut with scissors, such as the Sutherland scissors. This is very difficult, especially if the tags are in the lower pole. The described technique of capsulotomy

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was designed to avoid the occurrence of tags there. 4. A dialysis of the zonule may occur if the zonule was weak preoperatively, or if too much capsular tension is applied with the cystotome (the latter cannot occur if a sharp cystotome is used).

The capsulotomy should be continued so that all further capsule cuts are directed towards the dialysis, so preventing its extension.

Removal of the Nucleus The aim is to remove the nucleus without damaging the zonule or the endothelium.

The preferred method. The section is now cut large enough to allow the nucleus to be delivered. This is usually 10-12 mm chord length. At first, when learning this technique, cut the section larger rather than smaller.

A Sheet’s irrigating vectis directed posteriorly is used to indent the sclera 2 mm behind the incision. The pressure wave so caused bounces forward from the posterior pole and pushes the nucleus out into the incision (Figure 2). It may then be delivered by wheeling it with the vectis.

The irrigating vectis is now placed in the capsular bag, washing out the loose cortical material. Often hypermature cortex is completely removed this way.

Problems If the nucleus doesn’t deliver using the described method the section isn’t big enough, so enlarge it.

Figure 2.

AUSTRALIAN JOURNAL OF OPHTHALMOLOGY

Removal of the Cortex The aim is to remove as much of the cortex as is possible leaving the posterior capsule intact.

The cortex is removed by aspiration and strip- ping while the anterior chamber is maintained by irrigation. There are many coaxial aspiration irrigation systems, but the principles involved in their use are all the same.

Before commencing this stage of the procedure examine the anterior chamber and identify the anatomy in order to avoid possible problems. Look especially for troublesome tags of capsule.

Hold the irrigation/aspiration (I/A) instru- ment as a billiard cue. The right hand is the cue hand and it moves the I/A tip around the fulcrum secured by the bridging left hand. If a manual system is used the right fingers vary the pressure on the syringe plunger from positive, negative to zero as the situation demands..

The port should be 0.2 mm in calibre; if the cortex is soft 0.3 mm can be used. When positive aspiration pressure is applied the surgeon must know where the port is or inadvertently the capsule will be engaged and a capsule tear may occur. Do not apply strong aspirating pressure unless you actually see the port and so know that it is only cortex that is being aspirated.

My preferred method. The anterior capsular flap is grasped with forceps and brought outside the wound. It is then trimmed with scissors so that the anterior capsular flap in the upper pole is short, allowing good access to the cortex at 12 o’clock.

I use the Mclntyre 1/A system. The irrigation fluid used is Hartmann’s, containing one in a million adrenalin to maintain pupil dilatation. The irrigating bottle is 24 inches (61 cm) above the patient’s eye; the coaxial tip is inserted into the capsular bag. Starting at 6 o’clock the equatorial cortex is engaged by the port facing anteriorly. The cortex is stripped from its attachment to the capsule and brought into the centre of the capsular bag. This may involve several reapplications of the I/A system by applying positive pressure and then re-engaging the port.

When the cortex is well away from the cap-

sular remnants strong negative suction pressure may be applied; as long as the port is occluded by cortex the chamber will not collapse. If the anterior chamber starts t o collapse stop aspirating and reapply the port to incarcerate cortex. If the cortex is too tenacious and cannot be aspirated carefully strip the cortex right out of the capsular bag and eye.

You must be absolutely sure when stripping that it is only cortex engaged in the port. If capsule is incarcerated it will tear.

Using this method as much cortex as possible is removed. Do not be impatient; take your time and consciously be relaxed. This part of the operation cannot be hurried and this I found the hardest lesson of all to learn. Keep all air out of the syringe as the presence of an air bubble introduces elasticity to the system and reduces control. The barrel of the syringe should always contain one or two millilitres of the irrigating solution so that positive pressure on the plunger will immediately eject unwanted material incarcerated in the port.

Problems 1. Dialysis. The capsule may disinsert from the zonule and a dialysis occur. You will recognize this by noticing a chord-like line occurring beneath the area you are working at; this can be similar in appearance to cortical stripping, but if you look you will not see the capsular rem- nant peripheral to the cortical line.

On recognizing a dialysis disengage the port by applying positive pressure and, providing the vitreous face is not ruptured, it is often possible to remove the remaining cortex with great care, of course, not to extend the dialysis. 2. Hole in the posterior capsule. If there is no vitreous loss cortical removal should be pro- ceeded with; a little cortex left behind is less of a problem than vitreous loss.

If vitreous loss occurs an anterior vitrectomy must be done with a vitreous cutting machine or cellulose sponge and scissors. All the vitreous must be removed from the anterior chamber and air bubbles placed in the chamber to keep the vitreous posterior to the iris.

EXTKACAPSULAK C A I ARACT EXTRACTION 93