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The secret to a great capsulorrhexis
The capsulorrhexis should ideally overlap the optic a full 360°.
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When we examine an eye that had previous cataract surgery years ago, we see two things: the incision and the capsulorrhexis. And based on those, we sometimes make a judgment as to the skills of the previous surgeon. We have no idea as to the prior postop inflammation, corneal edema or even macular swelling — all of which have resolved with the healing process. How can we make the ideal capsulorrhexis in order to produce a beautiful result and, more importantly, to provide the best visual results for our patients?
The capsulorrhexis should ideally overlap the optic a full 360° and securely hold the IOL in position for decades to come. If we start the cataract surgery with a great capsulorrhexis, the rest of the case will unfold nicely with a lower risk for complications and better visual results for our patients. The capsulorrhexis stays intact during intracapsular maneuvers such as nucleus division and cortex removal, and it holds the IOL optic securely in position and keeps it planar for optimal refractive results.
The secret to the ideal capsulorrhexis is multifactorial:
Source: Uday Devgan, MD
Have great incisions, which help retain viscoelastic to keep the anterior chamber formed during capsulorrhexis creation.
Float within the incisions and pivot so that the anterior chamber is stable.
Use markings to measure the capsulorrhexis as it is created.
Use the tip of the forceps to trace a circle, and the capsulorrhexis will follow.
Many surgeons use the iris or pupil size as a guide for capsulorrhexis creation, but you should not. Do not fall into this trap. When we compare two eyes, an average eye and a larger myopic eye, after surgery, both eyes have the same model lens with a diameter of 6 mm and both have a capsulorrhexis that is about 5 mm in diameter, giving an excellent overlap of the optic. But the eyes are very different: The anterior segment size, the white-to-white measurement and the pupil dilation are all markedly different (Figure 1). In the large myopic eye, using the iris as a guide would have resulted in an overly large capsulorrhexis, which would not have held the IOL optic securely.
There are corneal marking instruments that allow the surgeon to place a round mark on the epithelium to help plan out the capsulorrhexis size. These markers are typically 5.5 mm in diameter, and by tracing the capsulorrhexis with this circular mark, the surgeon can create a 5-mm diameter capsular opening. The cornea provides a degree of magnification so that aligning a capsulorrhexis with the 5.5-mm corneal mark will result in a 5-mm diameter opening.
We can also use capsulorrhexis forceps, which are marked, and this is the technique that I recommend. At the beginning of the case, I hold the forceps to plan out the capsulorrhexis size. The mark that is 2.5 mm from the tip should be placed in the center of the intended circular opening, and then the 5 mm mark and the tip of the instrument outline the diameter of the ideal 5 mm capsulorrhexis. With this image in my mind, I then create the capsulorrhexis with these dimensions and position (Figure 2). At the end of the surgery, we can see that the capsulorrhexis is this desired size.
You do not need to purchase new forceps — you can simply make marks on your existing forceps or use another metered device such as a marked spatula. Some surgeons also look at the phaco incision to help judge size. A 2.5-mm phaco incision is the radius of the ideal capsulorrhexis size. Twice the phaco incision is about the size of the ideal capsulorrhexis diameter.
The main consideration in creating a great capsulorrhexis is the ability to pivot within the incision. This allows the anterior chamber to stay deep, and it prevents prolapse of the viscoelastic. Using viscoelastic to flatten the anterior lens capsule is a critical step in capsulorrhexis creation. When the anterior chamber is relatively shallow and the anterior lens capsule takes its normal dome shape, the capsulorrhexis will tend to run downhill and that means toward the zonular attachments. To facilitate capsulorrhexis creation, we need to use our viscoelastic to flatten the anterior lens capsule and deepen the anterior chamber. This will provide more working room and will give a planar capsular surface, which will make the capsulorrhexis creation easier because we can just move in a circumferential manner.
My advice to beginning surgeons is to first feel comfortable making a manual capsulorrhexis on a consistent basis, then feel free to try the femtosecond laser or other automated technology device. But do not sacrifice learning the manual skills with the idea that you will always just use the femtosecond laser because that may not be possible in all situations. Finally, one of the most personally satisfying parts of the surgery is seeing the overlap of the optic at the end of the case (Figure 3).
Full videos and further explanation can be found at www.CataractCoach.com.
- For more information:
- Uday Devgan, MD, is in private practice at Devgan Eye Surgery, Chief of Ophthalmology at Olive View UCLA Medical Center and Clinical Professor of Ophthalmology at the Jules Stein Eye Institute, UCLA School of Medicine. He can be reached at 11600 Wilshire Blvd. #200, Los Angeles, CA 90025; email: devgan@gmail.com; website: www.CataractCoach.com.
Disclosure: Devgan reports no relevant financial disclosures. He reports he owns and runs the CataractCoach.com website, which is free and noncommercial.
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