IOL scaffold prevents posterior capsule rupture in Morgagnian cataracts
The technique protects the posterior capsule and the zonular apparatus.
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IOL scaffold helps the surgeon not only in cases of posterior capsule rupture but also in preventing posterior capsule rupture in Morgagnian cataracts.
In this column, I would like to invite Drs. Rohit Om Parkash, Shruti Mahajan and Tushya Om Parkash to explain how this is done.
Amar Agarwal, MS, FRCS, FRCOphth
OSN Complications Consult Editor
Morgagnian cataract, a type of hypermature cataract, infrequently presents in developed countries. However, it is not uncommon in underdeveloped and developing countries where patients seek surgical management when the cataract matures. Subsequently, there is a regular presentation of Morgagnian cataracts in these ophthalmology clinics.
Morgagnian cataract
Morgagnian cataract is a challenge for surgeons of all levels of surgical expertise because of certain unique characteristics. There is the presence of a fibrotic or calcified anterior capsule, degenerated cortical fibers causing cortical liquefaction and diminished cortical support, variably sized hard and sclerotic nucleus floating freely in the bag, weak zonules, and degenerated, liquified and shrunken vitreous humor.
Difficulties operating on Morgagnian cataract
Challenges during nuclear emulsification include difficult sculpting or holding of the variably sized freely floating brunescent nucleus. The hard nucleus requires the use of high fluidics to be held and chopped. In the post-occlusion phase, the high fluidics make the posterior capsule lax and floppy because of absent epinuclear or cortical cushioning and vitreous liquefaction. Furthermore, the high aspirational fluidics predispose to additional zonulysis of the weak zonular fibers with eventual posterior capsule rupture and bag emulsification.
Prevalent surgical techniques
In order to save the posterior capsule and prevent bag emulsification, an ophthalmic viscosurgical device (OVD) shell technique is practiced. In this technique, Healon5 (sodium hyaluronate 2.3%, Johnson & Johnson Vision) is injected anterior and posterior to the nucleus to keep the bag inflated. However, the OVD shield is temporary, and posterior capsule rupture can still occur. Supracapsular emulsification is another surgical method to prevent posterior capsule rupture by keeping the nucleus away from the posterior capsule. However, phacoemulsification in close proximity of the corneal endothelium predisposes to collateral damage to the corneal endothelium. Some surgeons employ stepping down of the fluidics and using OVD shielding of the posterior capsule. Nevertheless, such surgical modifications are associated with difficulties in nuclear emulsification, and the posterior capsule can still rupture because the OVD shield is temporary.
IOL scaffold
We proposed the use of an IOL as a scaffold in Morgagnian cataracts to protect the posterior capsule from rupturing and the capsular bag from getting emulsified. IOLs have been used in different situations to act as a scaffold to protect the posterior capsule from rupturing (Figures 1 to 3).
Source: Rohit Om Parkash, MBBS, MS, Shruti Mahajan, MBBS, MS, and Tushya Om Parkash, MBBS, MS
Narang and colleagues described the use of a second IOL as a scaffold while doing IOL exchange. The faulty IOL is brought anteriorly out of the capsular bag. The second IOL to be used as a scaffold is implanted into the bag. This prevents posterior capsule rupture while the IOL is being explanted. Some surgeons have used an IOL as a scaffold when there is positive pressure. However, there is difficulty in removing the cortex after an IOL has been implanted. In brunescent cataracts, wherein high fluidics are used, surgeons implant the IOL before removing the last fragment.
In Morgagnian cataracts, the IOL is used as a scaffold to prevent posterior capsule rupture and bag emulsification. The bag is inflated with OVD, and the nuclear mass is maneuvered into the anterior chamber or in a plane anterior to the anterior capsule. The IOL is implanted into the bag. The timing of using the IOL as a scaffold depends upon the chamber stability in the post-occlusion phase. It can be done before removing the last nuclear hemisphere. However, in situations in which the nucleus is small, the non-fragmented nucleus can be maneuvered into the anterior chamber, and the IOL can be used as a scaffold early on while doing nuclear emulsification.
Advantages
Using an IOL as a scaffold is protective to both the posterior capsule and the corneal endothelium. IOL scaffold provides a stable barrier over the posterior capsule, with no fear of the floppy posterior capsule being ruptured. The IOL keeps the bag continuously expanded during nuclear emulsification, thereby decreasing the propensity of the weak zonular apparatus to zonular dehiscence and subsequent bag emulsification in response to the high aspirational fluidics. With the IOL as a scaffold and the posterior capsule fully protected, the surgeon can work at a deeper plane without fear of any collateral damage to the posterior capsule and the capsular bag. The fluidics need not be stepped down, thereby facilitating the apt use of fluidics as per the surgeon’s choice. The corneal endothelial protection is also maintained. Now, deeper plane emulsification is possible because of continuous protection of the posterior capsule by the IOL scaffold. The appropriate distancing from the corneal endothelium protects the cornea, which helps in achieving clearer corneas on postoperative day 1. Furthermore, the deeper plane emulsification allows the surgeon to use the chopper as a shield to the corneal endothelium by appropriately placing the chopper between the corneal endothelium and the phaco tip. The chopper can easily shadow the nuclear fragments and safeguard the corneal endothelium by preventing the chattering nuclear fragments from contacting the corneal endothelium.
The large rhexis in conjunction with IOL scaffold helps to decrease the stress on weak zonules.
In situations in which zonular dehiscence happens, the IOL works as a scaffold by keeping the bag distended and eases the use of capsular tension rings or capsular tension segments.
In Morgagnian cataracts, the IOL as a scaffold can be used at any stage of nuclear emulsification. There is no associated difficulty in cortex removal with an IOL in situ because the cortex is liquified, and there is minimal formed cortex that would require removal.
Conclusion
In conclusion, an IOL can be used as a scaffold in Morgagnian cataracts to have better surgical outcomes. There is a protection to the floppy posterior capsule and the fragile zonular apparatus, making it possible to implant the IOL without any complication. Patients have clearer corneas on postoperative day 1 as deeper plane emulsification away from the corneal endothelium is now possible.
- References:
- Luo L, et al. PLoS One. 2014;doi:10.1371/journal.pone.0112663.
- Narang P, et al. J Cataract Refract Surg. 2014;doi:10.1016/j.jcrs.2014.07.015.
- Parkash RO, et al. J Cataract Refract Surg. 2017;doi:10.1016/j.jcrs.2016.12.008.
- Sato M, et al. J Cataract Refract Surg. 2008;doi:10.1016/j.jcrs.2008.05.064.
- Spencer TS, et al. The pathology of cataracts. In: Steinert RF, ed. Cataract Surgery. 3rd ed. Saunders; 2010:3-8.
- For more information:
- Amar Agarwal, MS, FRCS, FRCOphth, is director of Dr. Agarwal’s Eye Hospital and Eye Research Centre. Agarwal is the author of several books published by SLACK Incorporated, publisher of Ocular Surgery News, including Phaco Nightmares: Conquering Cataract Catastrophes, Bimanual Phaco: Mastering the Phakonit/MICS Technique, Dry Eye: A Practical Guide to Ocular Surface Disorders and Stem Cell Surgery and Presbyopia: A Surgical Textbook. He can be reached at 19 Cathedral Road, Chennai 600 086, India; email: aehl19c@gmail.com; website: www.dragarwal.com.
- Rohit Om Parkash, MBBS, MS, can be reached at Dr. Om Parkash Eye Institute, 117-A, The Mall, Amritsar-143001, Punjab, India; email: drrohitop@gmail.com.
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