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IOL “scaffold” technique helps prevent dropped nucleus
By Linda Roach
When a posterior capsular rupture (PCR) occurs with vitreous prolapse and the nucleus still in the bag the stage is set for a possible nucleus drop. Most surgeons will respond by extending the corneal incision to deliver the nucleus.
But Amar Agarwal, MS, FRCS, FRCOpth, has invented a novel technique using the intraocular lens (IOL) itself as a temporary “scaffold” to prevent nucleus fragments from falling into the vitreous as cataract surgery continues, without the need to extend the corneal incision. The IOL functions as an artificial posterior capsule, said Dr. Agarwal, chairman and managing director of Dr. Agarwal’s Eye Hospital and Eye Research Centre in Chennai, India.
“You can emulsify the nucleus above the IOL very safely without any pieces falling down. Once this is complete, you can implant the same lens into the sulcus,” he said.
IOL Keeps Vitreous in Place
The IOL also prevents vitreous prolapse in the anterior chamber (AC) and decreases hydration of the vitreous from fluid in the AC, Dr. Agarwal said.
He presented his procedure to fellow ophthalmologists for the first time in Orlando, Fla., at the Annual Meeting of the International Society of Refractive Surgery (ISRS), which was held during Refractive Surgery Subspecialty Day at the Academy’s Annual Meeting. His co-authors on the paper were Dhivya Ashok Kumar, MD, and Soosan Jacob, MS, FRCS, DNB.
Dr. Agarwal’s group first used an IOL as an intraocular scaffold in June 2011. Since then, they have used the technique in 14 cases.
Position of Haptics is Key
During the procedure, a three-piece foldable IOL with modified loop haptics is partially injected into the eye. The leading haptic is above the iris and the trailing haptic stays outside of the incision, holding the lens in place. At the trailing optic-haptic junction, the IOL is maneuvered so that it blocks the pupil, separating the vitreous and the AC and enabling phacoemulsification.
“The fear people might have is that the IOL itself will fall down into the vitreous. But it will not fall down, because the haptic is above the iris,” Dr. Agarwal said.
IOL Scaffold Advantages
When PCR occurs, the IOL scaffold procedure has several advantages compared with other options, Dr. Agarwal said:
- It establishes a physical barrier to nucleus drop without any need to enlarge the phacoemulsification incision.
- There is no need for sutures that might induce postoperative astigmatism.
- Phaco and IOL implantation can be completed with a minimum of extra steps.
- Preventing nucleus fragments from falling into the vitreous eliminates added risks from secondary surgery for large dropped fragment removal.
Technique is Simple
“This procedure is very simple. It does not have to be done by a posterior segment surgeon. It is easily done by an anterior segment surgeon,” Dr. Agarwal said.
“At the end, you reposition the haptics, place the IOL in the sulcus and the case is complete,” he said.
The IOL scaffold procedure should be used only with moderate to soft nuclei that have not been phacoemulsified and remain in the bag, Dr. Agarwal said. Hard cataracts would require extracorporeal cataract extraction to manage a PCR, he said.
Building Steps for an IOL Scaffold
During his presentation at the ISRS meeting, Dr. Agarwal listed the following steps in the IOL scaffold procedure:
- An AC maintainer is introduced through a 1.2-mm stab incision with a micro-vitreoretinal blade. The maintainer should be kept be away from the PCR and the flow kept low.
- A vitrectomy cutter is used to remove vitreous prolapsed into the AC.
- An Agarwal globe stabilization rod (Katena Products, Inc., Denville, N.J.) is passed through the side port to help push the fragment away from the PCR and into the AC.
- A foldable IOL is injected via the existing corneal wound and maneuvered below the nucleus.
- The leading haptic of the IOL is positioned above the iris, and the trailing haptic is placed just outside the incision site.
- Using a dialer in the nondominant hand, the optic-haptic junction on the trailing side is maneuvered so that the IOL blocks the pupil. The IOL position can be readjusted readily if the nucleus rotates during phacoemulsification.
- The nucleus fragments are then removed with the vitrectomy cutter or a phaco probe (low flow and vacuum), depending on the density of the nucleus.
- A vitrectomy probe is used to remove cortex with suction and low aspiration.
- Once cortical cleaning is done, the IOL is placed over the capsular remnants in the ciliary sulcus.
- The AC maintainer is removed and wound hydration is performed.
- The patient is prescribed topical ofloxacin and corticosteroid eye drops four times daily for two weeks. Additionally a short-acting mydriatic drop is administered twice a day for the first three days.