January 2012

 

NEWS & OPINION

 

Anterior segment grand rounds

Reversal of misfortune


by Steven G. Safran, M.D.

 

This is a 48-year-old gentleman who was referred to me for an IOL exchange after he developed what was described as a recurrent "UGH" syndrome (uveitis/ glaucoma/ hyphema) in the left eye. He was a myope who had a retina detachment in the OS that required a pars plana vitrectomy, which led to the development of a cataract. The referring cataract surgeon told me that a three-piece acrylic implant had been placed in the sulcus because of compromise to the capsule and zonules. Although the eye had been quiet for 4 years after this, in the past 6 months the patient had three episodes of elevated pressure associated with inflammation and hyphema, and it was the most recent one that triggered his referral to my office.

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

 
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I saw the patient soon after his eye started "acting up" again. His vision was CF in the involved OS. IOP was 16 OD and 38 OS and the cornea had microcystic edema in the involved eye. A microhyphema was present and although the view was compromised I could see that the anterior chamber was very deep with the iris appearing bowed back with peripheral transillumination defects. Figure 1 is a slit lamp view of the eye at presentation. Note the hazy view through the cornea and the peripheral transillumination defects in the iris from 3:30 to 5:30.

Figure 2 is a gonioscopy image. Note the blood in the angle and the extreme concavity of the iris. It appears very posteriorly angulated.

At the time this case presented I was working with a very early prototype lens to adapt the Spectralis (Heidelberg Engineering, Carlsbad, Calif.) to perform anterior segment OCT. Figure 3 includes OCT images where I attempted to determine the configuration of the iris in relation to the IOL. Note the extreme posterior angle of the iris and the extensive contact with the implant optic. Figure 4 is another image demonstrating the iris configuration. Note the posterior bowing (there is an artifact in these images of an inverted cornea image projected behind the iris).

I presented this case to a stellar panelUday Devgan, M.D., Garry Condon, M.D., Daniel Goldberg, M.D., Baseer Khan, M.D., and Robert Nasser, M.D. for discussion on how they would proceed in managing this patient. Dr. Devgan commented: "This is truly a challenging case in an eye with unusual anterior segment anatomy If this patient has an open posterior capsule and in-the-bag placement is not possible then a scleral-fixated IOL could prove useful. Given the unusual iris configuration and the proclivity toward UGH syndrome, it may be wise to avoid any type of IOL that will interact with the iris including ACIOLs as well as iris-sutured PCIOLs." Dr. Nasser commented: "The anterior segment depth and iris configuration are puzzling to me. If the IOL was 13 mm or less in diameter it is likely mobile, causing iris trauma and hyphema I have seen a hyphema in a similar case potentiated by ASA or NSAID use and would be sure to stop those meds. I'd use medical therapy to lower IOP, and when (if) the cornea clears, re-evaluate the lens. I suspect it will need to be replaced with a capsular fixed lens (best) or a longer lens sutured to the sclera. I would avoid suturing to the iris or an ACIOL.I'd delay glaucoma surgery if you can."

Dr. Condon commented: "This is relatively weird! Is the capsular bag visible at all? Simple repositioning is not a likely option. You could elevate the IOL and do iris suturing but this may not alleviate the acute inflammatory problem. Exchange with scleral fix is a consideration. Removing the IOL and letting things quiet down and then going back later is probably what I'd favor.

"In a similar case, I brought the three-piece IOL into the AC, reinflated the bag, placed a ring in the bag, and then finally put the ENTIRE lens into the capsular bag."

Unfortunately in this case the option of reinflating the capsular bag was off the table because the bag was completely collapsed and had fibrosed years earlier, and he had an open posterior capsule with no evidence of a separate continuous anterior rhexis opening. Dr. Goldberg commented: "The key to this case is analyzing the source of the problema sulcus-placed PCIOL without optic capture overlying a damaged capsule in the enlarged posterior chamber of a high myope. The iris should not be considered for suture fixation, so the surgeon should be prepared with his/her best technique for scleral fixation. The added risk of exchanging IOLs is outweighed by the advantages of exchanging for a better- designed IOL (e.g., larger optic diameter, longer haptics, eyelets for scleral fixation)." Dr. Khan commented: "I don't think I've ever seen anything like this before with the posterior bowing of the iris and transillumination defect. This seems like a cross between reverse pupil block and pigment dispersion syndrome so the first thing I would do is try a PI; it might require a tap with a 30 g needle to clear up the cornea Failing this I would consider explanting the lens and letting the eye settle down It's an interesting case."

Most of the participants in this case discussion felt that there was an "unusual" or "weird" anatomy here, and this was indeed the case. It turned out that this patient did have reverse pupillary block. The reverse pupillary block created a vicious cycle of tension on the peripheral iris, stretching it, which caused intermittent bleeding. The blood combined with pigment dispersion caused by iris contact with the implant (exacerbated by pseudophakodonesis) caused clogging of the meshwork, build-up of pressure in the anterior chamber, and further pressure placed on the iris against the implant, creating a ball valve effect similar to what you see during cataract surgery in high myopes when you may get reverse pupillary block during surgery and have to lift the iris to break it. In this case all I needed to do was a laser peripheral iridotomy and the situation completely resolved. Figure 5 is an image of the eye immediately after the iridotomy.

The iridotomy broke the reverse pupillary block and the pressure dropped within an hour into the 20s. The next day the IOP was in the low teens where it has stayed for over a year without medication. Figure 6 is an image of his gonioscopy after the iridotomy. Notice how much less concave the iris is.

Figure 7 is an OCT image.Notice that the iris is flat and there is a gap between the iris and the surface of the IOL. (Compare this to the images taken before PI when the iris was distended back and jammed up against the optic.) I have now seen four patients in the last 18 months with a similar presentation of pseudophakic reverse pupillary block causing elevated IOP associated with either pigment dispersion, hyphema, or iris capture. All responded to laser iridotomy immediately, which broke the pupillary block. Figure 8 is before and after images of the iris from a second patient that presented with pseudophakic reverse pupillary block. Note that this patient had the same "finger"-shaped transillumination defects as the first patient did. This is due to the chronic extreme distension of the peripheral seen in these cases. Iris stretching, as well as iris contact with the IOL, may lead to hyphema while iris contact with the optic and haptics may lead to pigment dispersion, contributing to blockage of the trabecular meshwork. I believe this problem is fairly common but not recognized. All four patients I've treated were completely cured with laser iridotomy. In one patient who presented with recurrent iris capture after scleral suturing of a dislocated IOL, I did an IOL exchange first because I thought the IOL might have been sutured too anterior allowing the iris capture to occur. I replaced the three-piece silicone IOL with a more posteriorly fixated single-piece PMMA lens, and once again the patient presented with what I recognized as reverse pupillary block causing pigment dispersion and elevated IOP (rather than iris capture of the IOL), which completely resolved with a simple laser iridotomy. I have no doubt that the lens exchange could have been avoided with a simple LI done in the first place.

The other question these cases raise in my mind is whether or not it is possible to have a "compartment" syndrome in the eye where there are different pressures in the anterior and posterior segments. Many of us have seen a compartment syndrome in the case of capsular distention syndrome after cataract surgery that is relieved dramatically with a small YAG laser opening in the posterior capsule. That appears to be similar to what is seen in these cases of reverse pupillary block, and it would explain why the pressure drops so suddenly and dramatically after creation of an iridotomy as the pressure in the anterior chamber and posterior segment equilibrate. If that is the case, one could postulate that perhaps some of the patients we see with normal pressure glaucoma and narrow angles actually have a higher pressure in the posterior segment than what is measured in the anterior segment due to the presence of a traditional relative pupillary block. We've all seen the rush of fluid when we first "break through" doing a laser PI. Perhaps some of the patients we see in practice actually have higher pressures affecting the optic nerve than what we are measuring because of this "compartmenting" phenomenon. In all of these patients with reverse pupillary block the rush of fluid seen immediately after LI is in the reverse direction than one sees after LIs are done for routine narrow angle pupillary block (where the fluid gushes through into the anterior from the posterior chamber as soon as the YAG laser "breaks through" the iris). In these reverse pupillary block cases, as soon as break-through is achieved, the iris opening looks like a "vacuum" at the slit lamp, sucking fluid and pigment from behind the iris into the posterior chamber. An immediate and sustained drop in measured IOP may follow this. The movement of fluid seen through the opening created is opposite of what one normally sees when performing a PI in a narrow angle patient. This does suggest the possibility that pressure gradients can exist (in either direction) across the iris that are relieved with the creation of an iridotomy. Figure 9 shows a narrow angle with relative pupillary block prior to LI, and figure 10 is the same patient right after LI. Note the flattening of the iris and deepening of the angle.

Editors' note: Drs. Condon, Devgan, Goldberg, Khan, and Nasser have no financial interests related to their comments.

Contact information

Safran: safran12@comcast.net

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