Betty Lorente MD,FEBO
Cataract surgery in eyes with pseudoexfoliation can be very stressful, but there are many tools and techniques available to deal with its principal difficulties such as poor pupil dilation, and more important progressive zonular dehiscence preoperatively intraoperatively and postoperatively, reports Betty Lorente MD, FEBO, University Hospital, Ourense, Spain.
“The goal is to maintain the capsular bag in place to avoid inflammation through excessive manipulation, minimising complications and implant the lens in a safe position,” Dr Lorente told the 24th ESCRS Winter Meeting in Marrakech, Morocco.
She noted that in her region the rate of PEX among patients scheduled for cataract surgery is particularly high at 22% among those over 70 years and 33% among those over eight years. She added that every case of pseudoexfoliation is different and she presented the set of guidelines used at her centre to deal with most types of cases.
In eyes with PEX, the cataract surgeon should also be prepared with adequate tools for miosis, every degree of nuclear hardness and zonular weakness, she said. For example, she noted that she always likes to keep diluted triamcinolone at hand in case an anterior vitrectomy becomes necessary. It not only helps visualise any vitreous brand but also has an anti-inflammatory effect postoperatively.
Pupil dilation and hydrodissection
In eyes with PEX, preoperative exploration is very important, the cataract procedure begins before the patient enters the operating room, even before instillation of mydriatic drops, since phacodonesis is best observed in miosis. It is also important to look for indirect signs of zonular dehiscence such as an asymmetric anterior chamber depth, Dr Lorente said.
She usually uses local anaesthesia, but peribulbar and sub-Tenons may be considered for cases requiring longer and more difficult cases.
For pupil dilation, iris hooks -or capsular hooks- are the preferable tool in PEX cases, not only for economic reasons but also because they can help stabilise the capsular bag during the surgery. Once the capsulotomy is completed, the hooks may then be moved to the capsular rim if necessary to stabilize the bag during the phaco.
Dyeing the capsule with trypan blue can assist in capsulotomies. However, in eyes with zonular damage the dye can leak into the vitreous cavity causing loss of the red reflex. To avoid this problem we can stain the capsule injecting 2-3 drops of dye under the visco and “paint” it with the spatula. Hydrodissection should be performed multizonally, gently compressing the lens to prevent capsular blockage and rotating the nucleus with a bimanual approach to apply the force more evenly on the weak zonula and provide better control.
CTRs not always necessary
The role of the capsular tension ring (CTR) in PEX patients is controversial. Some authors advocate their use in all such cases. However, she said that in her experience CTRs are not necessary in all cases and do not appear to improve clinical outcomes. Besides which they can damage the zonule even when placed as carefully as possible.
She added that at her centre, CTRs will generally first be considered only if signs of zonular damage are present -as ovale shape of the CCC- and if this damage is less than four hours of the circumference.
She noted that CTRs should be implanted as late as possible during the procedure. Placing too early will make later manoeuvres to remove the lens more difficult. Placement of the ring is best achieved with a two-handed approach placed towards the area of zonular damage. Attaching a 10-0 nylon suture to the can be a useful precaution, should the ring need to be withdrawn, as would be the case in subluxation of the lens.
In eyes with weak zonules phaco-dissection begins with chop, or stop-and-chop technique. How-ever, she advises her residents to use the technique they are most comfortable with. A good divide-and-conquer is better than a bad chop, she stressed.
Young ophthalmologists must also learn techniques now rarely used, including intracapsular cataract extraction, when dealing with PEX cases.“Phacoemulsification has its limits and a subluxated lens with a hard nucleus and PEX is one of them,” she said.
She noted that she reinjects viscoelastic many times in her PEX cataract procedures, both to protect the endothelium and maintain the anterior chamber. For example, before withdrawing phaco tip at any time during surgery she first injects some viscoelastic. In hard cataracts she usually creates a small crater in the center of the nucleus and then chop (6-8 fragments). She performs bi-manual aspiration of the cortex and polishes the anterior part of the capsular bag that is going to be in contact with the IOL to avoid capsular contraction. Postoperatively, relaxing capsulotomies should be performed when there is any sign of capsular contraction to prevent capsular tension syndrome.
In all patients it is necessary to avoid postoperative IOP spikes, and it is particularly true in eyes with glaucomatous pseudoexfoliation. A useful measure in such eyes is to aspirate the viscoelastic near the trabeculum, Dr Lorente said.
Dr Lorente cautioned that even in a perfectly performed and uncomplicated procedure, one should be prepared for unexpected complications, such as late subluxation of an IOL.
“Pseudoexfoliation is not your friend, sometimes you think you’re just at the end of your procedure and then you're only at the beginning, again,” she commented.
