ESCRS - Soft cataract phacoemulsification ;
ESCRS - Soft cataract phacoemulsification ;

Soft cataract phacoemulsification

With cataract surgery slowly but surely moving into the realm of refractive surgery, more and more patients are presenting earlier for surgery and with softer cataracts.

Soft cataract phacoemulsification
TBC Soosan Jacob
Published: Tuesday, April 25, 2017
Fig A:The golden ring sign denotes a thorough hydrodelination. B: A horizontal chop is performed. The hemi-nuclei are brought out of the capsular bag and removed with supracapsular phacoemulsification using low power and high vacuum. C:Cortex aspiration. D: IOL implantation. With cataract surgery slowly but surely moving into the realm of refractive surgery, more and more patients are presenting earlier for surgery and with softer cataracts. A soft nucleus can be a vexing situation for the cataract surgeon who is accustomed to fracturing the nucleus into quadrants before removing them. Using vacuum to hold the nucleus for chopping results in the soft lens material aspirating into the phaco probe with resultant loss of suction. The chopper tends to cheese wire through the nucleus instead of cracking it into two. Trying to embed and extract tightly wedged quadrants can result in repeated loss of suction, ultimately creating a bowl of nuclear material. Further attempts can convert this bowl into a plate, increasing difficulty in removal. There is also the risk of the phaco tip going rapidly through the soft lens material and through the capsular bag, resulting in a posterior capsule rupture. The keys to successfully performing soft cataract phacoemulsification are to perform a good hydrodissection and hydrodelineation. A thorough hydrodissection makes complete cortex aspiration much easier. A good hydrodelineation should be done until a complete golden ring sign is seen. The size that the inner nucleus should be delineated to will depend on the size of the rhexis as well as the subsequent manoeuvre that the surgeon is planning. Here I will look at some techniques that are utilised for removing these soft cataracts. RHEXIS: Care should be taken to avoid a small rhexis which can cause difficulty in hydroprolapsing a soft nucleus. Attempts to embed and prolapse can result in a nuclear bowl that is difficult to extricate from within a narrow-mouthed capsular bag. It is ideal to aim for a rhexis that just overlaps the intraocular lens (IOL) optic all around. This has advantages of being large enough to allow hydroprolapse, while allowing 360-degree overlap of an in-the-bag IOL and also optic capture in case of any eventuality. A larger than normal rhexis does allow easier hydroprolapse but may not provide 360-degree optic overlap. HYDROPROLAPSE: My personal preference in a soft nucleus is to hydroprolapse it into the anterior chamber. This is done after performing hydrodissection. Too small a rhexis should be avoided, and if unavoidable, multiple hydrodelineation waves are performed until the nucleus is reduced in size to a more manageable one. The hydrocannula is then placed between the epinucleus and nucleus and while mildly depressing the posterior lip of the incision, multiple, gentle fluid waves are injected into this space until pressure builds up enough to prolapse a pole of the nucleus out through the rhexis. In case of very soft nuclei, the entire nucleus may be prolapsed into the anterior chamber. Care should be taken to not inject ‘too much, too fast’ behind the nucleus as this can cause a capsular block syndrome with consequent posterior capsular blowout. Prior to repeated attempts, the bag should be decompressed if the initial wave does not prolapse the nucleus. NUCLEUS REMOVAL: Once a pole is hydroprolapsed, the phaco probe is used to engage it and flip the nucleus out of the bag to perform supracapsular phacoemulsification. Low power settings are sufficient to remove the soft lens matter. Higher vacuum and flow rate can be used safely in the anterior chamber to rapidly aspirate the nucleus. If there is difficulty in hydroprolapsing the nucleus, it may be useful to debulk the central nucleus followed by another attempt at hydroprolapse. This is generally successful the second time around. A horizontal chop manoeuvre may be tried in soft nuclei with very minimal or no vacuum to hold the nucleus as the nucleus gets rapidly aspirated by the phaco tip. Alternately, the nucleus can be aspirated or sculpted in the centre to create a bowl which can then be flipped with viscoelastic and aspirated. Visco-fracture is a technique described by Malavazzi and Nery that involves injecting viscoelastic with a small amount of pressure into the soft nucleus to create a small central crack, which is then propagated in both directions to create a complete fracture. Further fractures can be created in other directions. This allows one to chop the nucleus within the bag. Very soft cataracts in the young or white cortical cataracts can be removed using just the irrigation/aspiration (I/A) probe alone. EPINUCLEUS REMOVAL: The epinucleus is bowl-shaped and is removed in toto. Thickness of the epinuclear shell depends on the density of cataract and the depth of hydrodelineation. The softer the nucleus and the deeper the plane of hydrodelineation, the thicker the epinuclear shell. With experience, the epinucleus that is left behind can be removed using the phaco probe with zero power and low vacuum.The epinucleus is engaged and slowly carouselled out of the bag. High vacuum settings can result in break of occlusion and aspiration of small chunks of the epinucleus. Trying this at various points can convert the bowl into a plate, making further removal difficult. If difficulty is experienced, the epinucleus may be viscoprolapsed to the centre of the bag with gentle but continuous injection of viscoelastic under the epinuclear bowl, while gently depressing the posterior lip of the incision. For beginners, another technique that is safer but takes longer is to partly strip the cortex quadrant by quadrant using the I/A probe, which results in loosening of the epinucleus from all sides. Once freed and brought to the centre, the I/A probe may be nudged under the loosened and displaced epinuclear shell with the aspiration port facing up and high vacuum (300-500mmHg) used. CORTEX ASPIRATION AND 
IOL IMPLANTATION: This is done as has been described in a previous column. Multi-quadrant cortical cleaving hydrodissection performed at the beginning of surgery goes a long way in helping easy and complete cortical removal. A bent I/A tip or bimanual phacoemulsification can help make sub-incisional cortex removal easier. The IOL is finally implanted in to the bag. Dr Soosan Jacob is Director and Chief of Dr Agarwal’s Refractive and Cornea Foundation at Dr Agarwal’s Eye Hospital, Chennai, India dr_soosanj@hotmail.com
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