Dealing with white cataracts
The challenge of white cataracts is not insurmountable with thoughtful strategy
When faced with white cataracts, some simple adjustments of technique at each step of their extraction can greatly enhance the safety of the procedure, said Angela Panico MD, at the 24th ESCRS Winter Meeting in Marrakech, Morocco.
For example, when performing a capsulorhexis in such eyes, staining the capsule with trypan blue can greatly aid in the visualisation of the capsule as the procedure progresses, considering the absent fundus reflex. Injecting a big bubble of air into the anterior chamber can prevent the staining of the endothelial cells, explained Dr Panico, San Giuseppe e Melorio Hospital, Caserta, Italy.
Prior to performing a capsulorhexis in such eyes, it is important to completely fill the anterior chamber using a high molecular weight ophthalmic viscosurgical device (OVD) in order to counteract the capsular bag pressure. She added that using a needle to open the capsule in white cataract allows the immediate aspiration of any milky fluid material, should it flow out of the capsular bag.
In white cataracts, a capsulorhexis slightly smaller than normal, about 5mm in diameter, will reduce the risk of the rhexis running out but will not be small enough to increase the risk of capsular block, Dr Panico said.
She noted that when performing the gentle hydrodissection that follows, she prefers to use the Buratto cannula, which has an angulated tip. Decompressing the anterior chamber at this point, by letting some of the OVD come out, reduces the risk of capsular block.
Once the lens rotates easily without adhering to the capsular bag and one has also assessed the stability and strength of the zonule, it is safe to proceed directly to phacoemulsification with, for example, a chopping technique, Dr Panico said.
She noted that in cataract procedures with low visibility she prefers the phaco chop technique. That is because the 1.5mm distance between the end of the phaco tip and the end of the silicone sleeve provides a gauge of the depth of tip in the lens, thereby allowing the safe performance of the phaco chop manoeuvre and eliminating the stress on the zonule.
“In a dense white cataract, special care is also necessary to remember the limits of ultrasound and to modify the fluidics of the phacoemulsification system accordingly. One should also pay close attention to the risk of wound burn and use a dispersive OVD in order to preserve the endothelial cells,” Dr Panico added.