January 2013

 

NEWS & OPINION

 

Anterior segment grand rounds

Taking the spin out of toric rotation: Part 2


by Steven G. Safran, M.D.

 

Steven G. Safran, M.D.

This is the second case in a two-part series looking at the subject of toric rotation and how to manage it. This is a young, male, high myope (53 years old) with a history of macula-off retinal detachment (RD) repair in the right eye who presented with rather impressive cataracts in both eyes. I did cataract surgery in the left eye first with a standard monofocal IOL, and the patient did very well with a 20/20 uncorrected outcome. The OD had 1.75 diopters of cornea astigmatism with the steep axis at 100 degrees and is 27.35 mm so an 11 diopter T4 was chosen with a surprisingly good post-op day 1 visual outcome20/40+ uncorrected. This is a bit better than expected because of the history of a macula-off detachment.

At one week post-op, however, he noticed that his vision had dropped, and he presented with uncorrected 20/100-1. The axis of the lens has rotated from 100 degrees as planned to 67 degrees. He refracts to about 20/30 with an Rx that includes about 1.5 D of astigmatism. The other eye is plano = 20/20. He is an avid golfer and sportsman and would like to avoid glasses for distance.

What would you do? He's one week post-op, and the IOL has rotated 33 degrees off axis, completely negating the astigmatic benefit of the toric lens.

Figure 1 is his post-op photo at one week showing the lens at 67 degrees when it should be at 100 degrees.

Steven G. Safran, M.D., ASGR editor

QR code

Watch this video on your smartphone or iPad using your QR code reader.

(Scanner available for free at your app store.)

 

Figure 1: Post-op at one week shows the lens at 67 degrees.

IOL in proper position post-op Source (all): Steven G. Safran, M.D.

Michael Wong, M.D., Princeton Eye Group, Princeton, N.J., commented, "Toric IOL rotational stability derives from at least five factors: rotational friction of the haptics at the equator of the capsular bag, the square edge of the profile of the IOL, the tackiness of the acrylic material, the adhesiveness of fibronectin between the IOL and bag, and later the fibrosis of the capsular leaves around the haptics.

"Conversely, post-operative rotation of the IOL can occur if the diameter of the bag is larger than the 13.0 mm haptic diameter (such as with a high myope), if there has been a disruption of the zonular apparatus so that the bag is not round (the IOL will tend to drift toward the greatest diameter), lack of evacuation of the VED (countering the effect of the tackiness of the acrylic material or laying down of fibronectin), or zonular variation or anterior capsular fibrosis that diminishes the fibrosis or 'shrink wrapping' of the capsular leaves (a case for not vacuuming all of the sub- anterior capsular cells). "This case is a high myope, but in addition, he had a vitrectomy. This surgery increases the risk of zonular disruption, making the bag irregular. In this case, insertion of a CTR makes sense.

"In my experience, sometimes practice does not follow theory. There are unexplained rotations and inexplicable refractive surprises. I then turn to corneal laser vision correction to erase the residual refractive error when not contraindicated."

Lisa Arbisser, M.D., adjunct clinical associate professor, John A. Moran Eye Center, University of Utah, Salt Lake City, and in private practice, Eye Surgeons Associates, Iowa and Illinois Quad Cities, would also implant a CTR here. "Since the CCC is on the optic, you can open the bag and insert a CTR and rotate the lens."

Jeff Horn, M.D., Vision for Life, Nashville, Tenn., on the other hand, would simply wait a bit, rotate and only use a CTR to facilitate rotation if it were proving to be difficult otherwise. "In this patient whose lens has rotated, I would wait at least three more weeks for the capsule to begin to contract. There is no rush. I would then return to the OR, viscodissect the lens with a dispersive OVD, and rotate it to the proper axis. If there were any difficulty in rotating it, I would implant a CTR, and then rotation will be easy."

Stephen Lane, M.D., medical director, Associated Eye Care, St. Paul, Minn., and adjunct professor of ophthalmology, University of Minnesota, would choose the option of anterior optic capture to "lock" the lens in place. "While keratorefractive procedures could be considered, they do not solve the basic problem of the lens being out of position, and the lens may continue to be unstable and rotate down the line. The photograph shows a well-positioned toric IOL in the bag with good overlap of the anterior capsule over the optic (at least for the 270 degrees or so that I can see). After viscodissecting the IOL free, I would prolapse the optic in front of the rhexis (reverse capsule capture) and rotate it to the proper position on the steep axis. This can be done quite atraumatically with minimal risk."

Because I have no personal experience with anterior optic capture, I was a bit uncomfortable with the idea of purposefully putting part of a single-piece AcrySof implant (Alcon, Fort Worth, Texas) anterior the rhexis where it could potentially contact the iris. I asked about experience with reverse optic capture (ROC) using the single-piece AcrySof platform on the ASCRS chat board and got this response from Jason Jones, M.D., medical director, Jones Eye Clinic, Sioux City, Iowa. "ROC is a capsule fixation technique where the haptics of the IOL are posterior to the anterior capsule and the optic is brought forward (captured) by the intact CCC. Several anatomic elements must be respected here. The CCC must be intact, smaller than the optic, and well centered. The zonules must be stable. And the CCC must be free of any vitreous (if the PC has been breached). Ideally the configuration of the iris relative to the capsule should be assessed; I don't have any numbers to recommend here, but there should be good clearance to avoid iris-optic contact. Given that the cataract has been removed and the IOL occupies much less space, I feel it is reasonable to assume most (not all) eyes will avoid such contact. In the case of repositioning a toric with ROC, this can and should be considered. Once the lens is rotated into position then the optic can be brought forward to obtain capture. Now, I have not had an opportunity to use ROC for a misbehaving toric lens. But I have implanted a series of AcrySof single-piece acrylic IOLs using ROC. In these cases the PC was damaged during primary surgery, and I elected to use this technique. All of my patients have done very well with clear visual pathways, no UGH syndrome, no RD, no decentration, and with up to four years or more follow-up in select cases. This is not sulcus fixation, and the issues that AcrySof SPA IOLs in the sulcus have encountered should not be conflated with ROC."

Dr. Jones' experience with this technique should be comforting to those who may consider it. In a follow-up email, Dr. Lane did add that he has done ROC "twice with good results and no iris chafe." I do have the personal experience of having treated six cases of pseudophakic reverse pupillary block that caused contact between the iris and IOL leading to iris chafing and pigment dispersion. I reported and discussed this phenomenon in the ASGR column of the January 2012 issue of EyeWorld, "Reversal of misfortune." All patients were vitrectomized high myopes (as is the case here) so I believe that if one wishes to consider ROC in a vitrectomized high myope, one should also consider placing a peripheral iridotomy to prevent the possibility of reverse pupillary block occurring, which could lead to the iris being pushed back against the optic, leading to chafing. In this case I chose to simply wait five weeks and reposition the lens. My own experience is that if you reposition the lens immediately, it is very likely to rotate again. If, on the other hand, you wait a few weeks for some fibrosis to occur, the bag will shrink wrap a bit around the lens, and the lens will not rotate a second time. Although a CTR could have been used, I discussed the option with the patient who wished not to have one placed unless I felt it was absolutely necessary. In this case I did not feel that it was so we chose not to use it. The patient ended up with a 20/30 final outcome and no repeat rotation (Figure 2). One does not want to wait so long that the haptics become so strongly fibrosed in place that they are impossible to free up but long enough that there is some shrink wrapping of the bag around the lens so that the lens is not likely to rotate a second time. Although we don't know the exact timeframe for this, it is likely that waiting five to six weeks post-op from the original cataract surgery is a pretty safe play.

One tip is that if you know the axis the lens is at, you don't need to mark the patient sitting up. For example, in this case the lens was measured at an axis of 67 degrees at the slit lamp, so I simply made a mark 33 degrees in the counterclockwise direction under the surgical microscope knowing that this would be exactly 100 degrees and then I rotated the lens to this point. I like to use a flat tip LASIK cannula (Katena K7-5106, Denville, N.J.) to get under the edge of the anterior capsule and initiate viscoelastic dissection. When you reopen the bag there is no need to "hyperinflate" with viscoelastic but rather to reopen just enough to easily facilitate rotation. The capsular bag exhibits a slightly different stiffer feel at six weeks out then it does at the time of initial cataract surgery due to fibrosis, and I believe this is what prevents the lens from rotating again. After rotation the viscoelastic is removed and the case is completed. Again, the CTR turned out not to be necessary. If I were to treat a patient who was not willing to consider waiting 4-6 weeks for a rotation then I would definitely use a CTR, but if you can wait a bit to do the repositioning, a CTR is probably not needed. If this lens were to rotate again, I would consider adding a CTR, and finally if it rotated a third time, reverse optic capture with a laser iridotomy could be considered as a final option.

Editors' note: Drs. Arbisser, Jones, Lane, and Wong have no financial interests related to this article. Dr. Safran has financial interests with Bausch + Lomb.

Contact information

Arbisser: drlisa@arbisser.com
Horn: jeff.horn@bestvisionforlife.com
Jones: jasonjonesmd@mac.com
Lane: sslane@AssociatedEyeCare.com
Safran: safran12@comcast.net
Wong: mwong2020@gmail.com

Taking the spin out of toric IOL rotation: Part 2 Taking the spin out of toric IOL rotation: Part 2
Ophthalmology News - EyeWorld Magazine
283 110
216 162
,
2017-03-31T11:04:24Z
True, 1