Rotating the Intraocular Lens to Prevent Posterior Capsular Opacification in Cataract Surgeries
Summary
The present protocol describes removing residual epithelial cells by rotating the intraocular lens in extracapsular cataract surgery without extra tools for preventing posterior capsular opacification.
Abstract
Posterior capsule opacification (PCO) is a common postoperative complication of extracapsular cataract surgery, which is caused by the proliferation and migration of lens epithelial cells and can affect long-term visual outcomes significantly. The most effective treatment for PCO is neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy; however, this treatment is associated with posterior segment complication and can break the stability of capsular bag, affecting the position and function of trifocal or toric intraocular lenses (IOLs). Advances in surgical procedures, IOL design, and pharmacy have reduced the rate of PCO in recent years, concentrating on the inhibition of proliferative lens epithelial cells (LECs). This protocol aimed to clear LECs more thoroughly during phacoemulsification and IOL implantation. The first several steps, including clear corneal incision, continuous circular capsulorhexis, hydrodissection, hydrodelineation, and phacoemulsification, were completed as conventional procedures. After placing the IOL into the capsular bag, rotation of the IOL by at least 360° was performed using an irrigation/aspiration tip or a hook, with slight stress on the posterior capsule. Some residuals occurred in the originally transparent capsular bag after rotation of the IOLs. Then, these materials and the viscoelastic were cleared completely using an irrigation/aspiration system. A clear posterior capsule was observed after the surgery in patients undergoing this method. This method of rotating IOLs is a simple, effective, and safe way to prevent PCO by clearing residual LECs and can be carried out without extra tools or skills.
Introduction
Cataracts are the most common cause of blindness worldwide, characterized by a clouding of the lens. The only means of treating cataracts is surgical intervention by removing the opaque lens, which restores high visual quality. However, a secondary reduction of visual quality, termed posterior capsule opacification (PCO), develops in 20%-40% of patients within 2 to 5 years after surgery1. This article introduces a method to further remove residual lens epithelial cells (LECs) left in the capsular bag in cataract surgery by rotating the intraocular lens (IOL) to prevent PCO.
PCO is a process caused by LECs, which are inevitably left in the capsular bag following cataract surgery and then begin to proliferate and migrate2. During phacoemulsification, a capsular bag is generated by continuous curvilinear capsulorhexis in the anterior capsule, which comprises a part of the anterior capsule, the equatorial capsule, and the entire posterior capsule2,3. In most patients, an IOL is implanted into the capsular bag. A transparent capsular bag, especially the posterior capsule, permits the light to transmit into the eyes, which is necessary for good postoperative visual quality4. A proportion of LECs are usually still attached to the capsular bag. As a reaction to the surgical trauma and a foreign body response toward IOLs, the residual epithelial cells start to proliferate and occupy first the remaining part of the anterior capsule, and then all available surfaces, including the surface of IOL and, most importantly, the previously acellular posterior capsule4. Subsequently, cells continue to divide, ultimately covering the entire posterior capsule and affecting the visual axis. The following changes, including fibrosis and regenerative form5, can cause significant visual impairment6.
PCO that affects visual acuity can be treated with capsulotomy of the posterior capsule, usually by a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser and sometimes a surgical procedure4. Recent studies report that the incidence of Nd:YAG capsulotomy for treating PCO 3 years after surgery is between 5% and 20%7,8. However, this procedure can break the normal posterior capsular morphology and wrinkle the posterior capsule, thus likely affecting the position of IOLs, which is unfavorable to the long-term visual outcome of IOLs, especially multifocal IOLs, and toric IOLs6. Advances in surgical procedures, IOL design, the pharmacological inhibition of LEC proliferation, and the induction of LEC apoptosis have been confirmed useful in preventing PCO, most of which target the LECs9.
LECs are normally distributed over the inner side of the anterior lens capsule in single-layer form1. LECs distributed in the area around the equatorial lens are the natural site of division, which is known as the germinative zone, while the dividing cells are also observed on the anterior capsule10,11. It has also been shown that equatorial cells can proliferate and migrate in the posterior capsule12. Residual LECs in the capsular bag are responsible for PCO. If LECs in the germinative zone are cleared as much as possible during cataract surgery, the possibility of PCO occurring postoperatively decreases as a consequence. As far as it is known, routine phacoemulsification does not include a procedure to remove equatorial LECs. In a study in India, the author proposed that rotation of the IOL by a Sinskey hook13 in the capsular bag decreases PCO and Nd:YAG capsulotomy rate.
Here, we introduced a method by rotating the IOL using an irrigation/aspiration (I/A) tip in the capsular bag to prevent PCO in cataract surgeries. The rationale of this method relies on the mechanical contact between the IOL and the capsular bag, especially the equatorial area, to remove residual LECs. Compared with treating PCO using Nd:YAG capsulotomy, the prevention of PCO maintains the integrity of the posterior capsule and the correct position of IOLs. Additionally, this method is cost-effective and requires no extra tools, which applies to cataract phacoemulsification and IOL implantation. Different from anterior capsule polishing, which is conducted using an I/A tip in the polishing mode of the phaco system6,14, the rotation of the IOL is conducted after the IOL implantation and is supposed to further remove visible lens matter (cortex) and cells.
Protocol
Representative Results
Discussion
There are some benefits to this method. Firstly, residual LECs in the capsule bag were reduced further, especially those in the equatorial area, and the possibility of PCO occurrence was reduced rationally. Secondly, a reduced possibility of PCO means a lower rate of Nd:YAG laser treatment, providing the opportunity to maintain the integrity of the capsule bag and effective lens positions and functions. Thirdly, this method can be achieved with available instruments in cataract surgery without additional preparation. In …
Divulgaciones
The authors have nothing to disclose.
Acknowledgements
This article is funded by Beijing Haidian Innovation and Transformation Project, HDCXZHKC2021212.
Materials
| 20 G Sideport MVR Knife | BVI | 378231 | To make corneal incision |
| 3.2 mm Slit Blade | BVI | 378232 | To make corneal incision |
| Balanced salt solution | Xingqi | H19991142 | Compound electrolyte intraocular irrigating solution |
| Centurion vision system | Alcon Laboratories | 8065753057 | The Centurion Vision System is indicated for emulsification, separation, irrigation, and aspiration of cataracts, residual cortical material and lens epithelial cells, vitreous aspiration and cutting associated with anterior vitrectomy, bipolar coagulation, and intraocular lens injection. |
| Compound tropicamide eye drops | Xingqi | Zhuobian | To dilate the pupils before the surgery |
| Disposable sterile irrigator | WEGO | 100038404339 | To complete hydrodissection and hydrodelineation |
| Fenzl lens insertion hook and manipulator | Belleif | IF-8100 | IOL positioning hook |
| Levofloxacin eye drops | Santen | Cravit | To prevent ocular infection before the surgery |
| Mini-flared Kelman tip 30DG | Alcon Laboratories | 8065750852 | To complete phacoemulsification |
| One piece intraocular Lens | Zeiss | AT TORBI 709M | Intraocular lens |
| Oxybuprocaine hydrochloride | Santen | Benoxil | Topical anesthesia |
| Phaco handpiece | Alcon Laboratories | 8065751761 | To complete phacoemulsification |
| Sinskey hook | Belleif | IF-8013 | For chop |
| Ultraflow II I/A tip | Alcon Laboratories | 8065751795 | To complete irrigation and aspiration |
| Utrata capsulorhexis forceps | Belleif | IF-3003C | To complete continuous circular capsulorhexis |
| Viscoelastics/Medical sodium hyaluronate gel | Bausch&lomb | iviz | Maintaining the anterior chamber and capsular bag |
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