OVD bolus: Putting the eye to the grindstone

Reviewed by Dr Andreas F. Borkenstein.

Refinement of a procedure to remove residual cortical material adjacent to the posterior lens capsule during cataract surgery without the need for additional instrumentation seems safe and highly effective in the first cases in which it was performed. Dr Andreas F. Borkenstein, who is in private practice in Graz, Austria, presented this finding and other data at the American Society of Cataract and Refractive Surgery’s 2022 annual meeting in Washington, D.C.

Development of the procedure

Dr Borkenstein noted that the step of removing any cortical remnants and primary capsular fibrosis is critical in cataract surgery because, otherwise, damage to the posterior capsule can occur. However, with normal jetting during the procedure, residues often remain, or the capsule can be destroyed by the pressure of the jet stream.

Dr Borkenstein explained that the idea to use a fluid stream from the irrigation cannula attached to the balanced salt solution (BSS) syringe to clean the capsule dates back to the late 1990s and was devised by Dr Steven Arshinoff and Dr Thomas Neuhann. The safety and efficacy of the procedure has been reported.^1,2

It was in 2020 that Dr Borkenstein first devised his new technique. The idea arose out of his recognition of the “excellent” capability of a highly viscous cohesive ophthalmic viscosurgical device (OVD; Pe-Ha-Luron F 2.2%, Albomed) to remove primary capsular fibrosis without damaging the posterior capsule with the irrigation/aspiration cannula when performing the mechanical capsular polishing step.

Over the course of 2021, Dr Borkenstein sought the assistance of an ophthalmologist with a significant surgical and scientific background. His search led him to Dr Boris Malyugin, a professor of ophthalmology and deputy director general at the S. Fyodorov Eye Microsurgery Federal State Institution in Moscow, Russia. Dr Malyugin, an internationally recognised expert for challenging cases in cataract surgery and the inventor of a number of useful instruments, became the co-author of Dr Borkenstein’s study.

The difference between the existing procedure for cleaning the capsule and the newer technique is that the latter does not use a BSS stream but rather a bolus of the OVD. This approach is an attempt to avoid excessive collateral irrigation trauma to the delicate corneal endothelium and posterior capsule.

As Dr Borkenstein explained, cohesive OVDs seem ideal for this technique in that they have a high molecular weight and high surface tension and are made of large molecules. In addition, they are ideal for maintaining the anterior chamber and helping to perform the capsulorrhexis, and for creating space, and they are easy to remove because of their high surface tension.

The procedural steps

Dr Borkenstein outlined the three-step process. Firstly, the capsular bag is filled to about a third of capacity with the cohesive, highly viscous OVD to create the bolus. Secondly, the surgeon increases the BSS jet stream by introducing a 27- or 30-gauge cannula attached to the syringe and directing it towards the posterior capsule, slightly tangential to the OVD bolus.

Finally, the OVD bolus starts to rotate and creates a “grindstone” of sorts. Dr Borkenstein explained that this effect can be detected when the thick viscoelastic cords start to rotate quickly in the capsule as a ball with a relatively rough surface that grinds down the cortical material.

The jet stream remains in the same position: tangential to the posterior capsule. Air bubbles in the anterior chamber also remain at the same location, indicating that no fluid or shear forces reach the anterior chamber or the endothelium/cornea.³

The first OVD cases

Dr Borkenstein reported that the first 62 cases were performed without problems. There were no intraoperative or postoperative complications detected, and on Day 1 after surgery, there was no corneal oedema or hypertension. The mean best-corrected visual acuity was –0.01 ± 0.11 logarithm of the minimum angle of resolution.

The procedure seems to be safe with no additional irrigation trauma and no pressure, mechanical force or sharp objects applied to the capsule. “The anterior chamber and corneal endothelium also are safe because the OVD remains in the capsule due to its molecular weight,” Dr Borkenstein said.

The new technique added only 30–60 seconds to the time of the routine cataract surgery.⁴ A major advantage in challenging cases is that the technique may potentially result in a lower risk of posterior capsular opacification (PCO) developing postoperatively.

In addition, additional surgical devices were not needed. It is safe and simple; Dr Borkenstein noted that it is therefore ideal for challenging cases such as post-traumatic eyes, pseudoexfoliation syndrome or floppy iris syndrome.

Dr Borkenstein explained that it will be interesting to see over the long term whether the PCO rate decreases as a result of this technique, and, with more surgeons performing the technique worldwide, if the intraoperative complication rate can be reduced.

A further multicentre study is planned to evaluate the long-term results regarding the PCO rate and endothelial cell count with more patients. In addition, Dr Borkenstein would like to demonstrate the grindstone effect in a laboratory study using the “Miyake-Apple posterior video analysis technique” and is seeking further collaboration.

Andreas F. Borkenstein, MD

E: crustalith@gmx.at

This article is adapted from Dr Borkenstein’s presentation at the 2022 American Society of Cataract and Refractive Surgery annual meeting, held in Washington, D.C. He has no financial interest in any aspect of this article.

References

1. Liu Z, Cao Q, Qu B, et al. Fluid-jet technique to polish the posterior capsule for phacoemulsification surgeries: efficacy and safety evaluation. J Cataract Refract Surg. 2020;46:1508-1514.

2. Arshinoff SA, Neuhann T. Comment on: Fluid-jet technique to polish the posterior capsule for phacoemulsification surgeries: efficacy and safety evaluation. J Cataract Refract Surg. 2021;47:1103.

3. Borkenstein AF, Borkenstein EM, Malyugin B. Removing residual cortical material during cataract surgery: visco polishing and the grindstone effect as a new surgical technique. Eur J Ophthalmol. 2022;32:1817-1820.

4. Borkenstein AF. Visco polishing technique. Accessed 24 Feb 2022. https://www.youtube.com/watch?v=iulMd2GvXsw&t=12s