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CATARACT & REFRACTIVE
WHITE CATARACT PHACOEMULSIFICATION Everything you ever wanted to know about white cataract phacoemulsification – Part 2. Dr Soosan Jacob reports
A
fter rhexis, the next challenging step in white cataract is nucleus removal. The approach to nucleus management depends on the type of white cataract.
MEMBRANOUS (CONGENITAL OR TRAUMATIC) WHITE CATARACT:
A membranous cataract has partial/ complete resorption of cortex, and a flattened membranous capsule consisting of the collapsed capsular leaflets is seen. In cases with partial resorption of cortex, rhexis and other usual steps are done followed by intraocular lens (IOL) implantation within the bag. In congenital cases, a primary posterior capsulorhexis and vitrectomy may also be done. If the cortex is completely resorbed, management aims at opening the visual axis. Depending on the nature
of the membrane, a rhexis is created or a vitrector is used to cut the membrane in as round and regular a manner as possible. The IOL may then be placed in the sulcus with membrane capture of the optic as described by Gimbel. With inadequate/ unstable capsular support, a scleral or iris-fixated IOL may be done depending on surgeon preference. My personal preference here is to perform a glued IOL.
TRAUMATIC WHITE CATARACT: A white cataract may be seen after penetrating or blunt trauma. If surgery is done soon after trauma, depending on the patient’s age, the cataract may be composed either of only soft, flocculent lens material or it may have an endonucleus. In the former case, it is sufficient to use an irrigation/ aspiration (I/A) probe to aspirate the soft lens matter.
However, in the presence of an endonucleus, special manoeuvres are adopted for nuclear disassembly. In all cases, the possibility of an associated posterior capsular rupture and weak zonules should be kept in mind. Hydro manoeuvres should not be done or should be done very gently, to prevent a nucleus drop in case of a pre-existing capsular rent. All manoeuvres should be performed gently. Other associated ocular comorbidity such as corneoscleral tear, scarred visual axis, difficult visualisation, soft eye, iris or vitreous loss, subluxation, secondary glaucoma, macular pathology, retinal detachment etc should be kept in mind while planning management. Blunt trauma classically presents as a rosette-shaped cataract with the possibility of coexisting zonulodialysis.
SENILE WHITE CATARACT: These can be seen as mature hard white cataracts or hyper-mature white leaking Morgagnian cataracts.
MATURE HARD WHITE CATARACT:
A small-sized rhexis is initiated
EUROTIMES | JUNE 2017
It is then spiralled out in a controlled manner to achieve the desired size
The entire cortex is opacified and there is very little epinucleus. The nucleus of the white cataract is large, but generally brittle and more amenable to phacoemulsification than hard, brown, leathery cataracts. Care needs to be taken to decrease total phaco time, power and energy used and to keep the corneal endothelium and the posterior capsule safe. Standard nuclear disassembly techniques may be used. Vertical chop works well