CASE PRESENTATION
You are asked to see a female patient, aged 53 years, who underwent uncomplicated phacoemulsification in her right eye, through a temporal clear corneal incision 2-weeks previously. According to the clinical record, the patient had an UCVA of 20/30 with no complications on day 1 postop review. On the second or third day postop, however, the patient noticed that her pupil was distorted—but because her vision was stable and there were no other symptoms, she assumed this would settle down. Unfortunately, it persisted, and the pupil remains peaked (Figure 1). What are the possible causes of this? Could it have been prevented? How would you manage this problem?

ROBERTO BELLUCCI, MD
This eye has a peaked pupil as the result of a vitreous strand that is clearly visible in Figure 1. The vitreous strand is incarcerated into the corneal wound, thus maintaining the peaked pupil. The rupture of the posterior capsule or rupture of the zonular fibers—can produce a small vitreous strand within the anterior chamber. Since we are told surgery was uncomplicated, we must assume a zonular dehiscence or rupture occurred during phacoemulsification or lens implantation. The complication probably occurred during the last surgical phases, which explains why the surgeon might have been unaware.

The small vitreous strand floating in the anterior chamber at the end of surgery could have been entrapped within the wound at a later time, due to anterior chamber shallowing (eg, a result of eye rubbing). Together with the surgical mydriasis, this could explain a round pupil immediately after surgery, and a peaked pupil after 48 hours.

Zonular dehiscence or rupture can occur at any time during cataract surgery, especially if there are predisposing factors. Among them, high myopia, pseudoexfoliation and other connective tissue disorders, or previous ocular trauma are the most common causes. Incorrect manoeuvres during surgery can also lead to zonular rupture, more often with small capsulorrhexis during phaco, or during lens implantation if the anterior and posterior chambers are not filled with enough viscoelastic material. Hydrophobic acrylic lenses are at high risk in this respect, with possible zonular or even capsule rupture at the time of implantation.

Although this peaked pupil probably will not result in damage to vision, this eye cannot be left unmonitored. The presence of the vitreous strand will determine an increased risk of infection for the eye (eg, vitreous wick syndrome) and cystoid macular edema may be associated with anterior vitreous distortion (eg, Irvine-Gass syndrome) following cataract surgery. Additionally, beside the aesthetic relevance and the few visual disturbances due to a probable small amount of glare, the patient will tend to attribute any eye or vision problem he/she will experience to the poor surgical outcome.

The surgical repair of this vitreous strand can be performed under topical anaesthesia. It is impossible to push the vitreous inside the eye through the same incarcerating wound. We need a second entrance where Miochol (Novartis Pharmaceutical; Basel, Switzerland) and viscoelastic can be injected, and where the strand is dragged inside the anterior chamber with a vitreous hook.

An anterior vitrectomy is then necessary, assisted by irrigation through the original wound and followed by I/A of the residual viscoelastic. It is better not to leave the strand within the eye, for the risk of repeated incarceration and of infection. As the lack of sutures was one cause of the complication, I would suture both incisions with 10/0 nylon. I would then relieve the sutures after 10 to 15 days.

MASSIMO BUSIN, MD
Pupil distortion after cataract surgery may occur for several reasons: vitreous loss with herniation through the pupil often into the surgical wound; retained anterior capsular flaps; IOL loop entrapping the iris root from its posterior surface; and dehiscence of the cataract surgical wound with iris prolapse.

When pupil distortion is not observed immediately after surgery, as in this case, a leak from the clear cornea tunnel is the most frequent cause. Minor trauma or even resolution of postsurgical edema can destabilize the architecture of a rather poorly constructed clear cornea tunnel, and result in loss of water tightness with consequent iris tamponade. Careful inspection of the clear cornea tunnel at the end of surgery is essential to prevent this type of complication. This can be done by gently applying mechanical pressure on the tunnel area. Although iris tamponade is usually effective in reestablishing water tightness (thus eliminating the risk of intraocular contamination, especially in the early postoperative period), the iris should be repositioned and the wound should then be closed with one or two 10/0 nylon stitches. Keep in mind that during this time, epithelium may grow on the iris surface, if it has prolapsed completely through the wound. Therefore, before repositioning the prolapsed iris, mechanical debridement of its anterior surface is mandatory. In this case, however, the surgical wound is quite clear and does not show any alteration.

Each of the other three possible causes mentioned above usually result in distortion of the pupil as soon as dilation subsides and the pupil constricts, (ie, usually as early as postoperative day 1). Sometimes, however, mydriasis induced pharmacologically at the time of surgery does not subside by the time of the first postoperative examination. This may make it difficult to detect any abnormal change in pupil shape. In this specific case, the picture shows some kind of ectopic substance at the site of pupil ovalization extending to the surgical wound and causing traction on the iris. Most certainly, an iris tuck due to improper positioning of an IOL loop can therefore be ruled out. In Figure 1, it is impossible to tell for sure whether the substance is prolapsed vitreous or an anterior capsule. The surgical record showed no intraoperative complication, but a small zonulolysis with subsequent vitreous prolapse into the anterior chamber may have occurred without the surgeon detecting it. The capsulorrhexis was similarly described as uneventful, but a small tear could have caused formation of an anterior capsular flap that could have prolapsed into the surgical wound. The difference between the two situations is substantial: Vitreous in the wound represents a threat of possible retinal complications and needs be removed by performing an anterior vitrectomy. On the other hand, a capsular flap prolapsing into the surgical wound is not dangerous for itself—as long as the surgical wound is water-tight—and could therefore be left untreated. The revision of this complication with either case is a simple and minimally invasive procedure, so I would not hesitate to resort to surgery. If the surgeon cannot diagnose whether they are dealing with vitreous or anterior capsule by slit-lamp examination, surgery represents the safest option.

RASIK VAJPAYEE, MS, FRCS(Ed), FRANZCO
It is possible that a peaked pupil results damage to an iris by a phaco probe or a chopping instrument. The inadvertent chaffing of the iris may (1) cause entrapment of some strands of the iris at the wound and (2) affect the shape of the pupil. A repeated prolapse of the iris from the main wound during surgery, may cause such an occurance.

To address this, a small amount of intracameral Miochol at the end of the surgery constricts the pupil and brings it to its physiological size. That can be helpful in keeping the iris away from the wound side. Air can also be injected into the anterior chamber at the end of the surgery and using a thin iris spatula from the side port, can sweep the strands of iris away from the wound site.

A small capsular tag or cortical matter, which can appear in the pupillary axis, could further cause pupillary peaking in the postoperative period. Prevention includes creating a continuous capsulorrhexis with a smooth margin as well as complete cortical removal at the end of the surgery.

Other reasons include preoperative or intraoperative capsular bag dialysis through which a vitreous tag comes into the pupillary axis. Also, there could be a small posterior capsular rent that was unidentified at the time of the surgery.

To prevent this capsular bag, dialysis should be identified. If any vitreous is identified, anterior vitrectomy should be performed. A small vitreous tag can be reposited back with the help of iris repositor.

If the peaking of pupil is caused due to an iris strand or a small vitreous strand, a Nd:YAG laser can be used to break these. Subsequently, 2% topical pilocarpine drops, two to three times daily, may be used to bring back the pupil to normal shape. The same strategy may be used if a small capsular tag causes the distortion of pupil. If Nd:YAG laser fails to produce the desired result, the strands or capsular tag may be swept away from the wound under air using a fine iris spatula or cannula.

Roberto Bellucci, MD, is the Head of the Ophthalmic Unit at the University Hospital, in Verona, Italy. He may be reached at robbell@tin.it. Dr. Bellucci is a member of the CRSToday Europe Editorial Board.

Massimo Busin, MD, is a professor of Ophthalmology and Director of Ophthalmology at Villa Serena Hospital, in Forli, Italy. He may be reached at mbusin@yahoo.com.

Rasik Vajpayee, MS, FRCS (Ed), FRANZCO, is the Head of Corneal and Cataract Surgery and Professor of Ophthalmology in the Centre for Eye Research Australia and University of Melbourne. He may be reached at Rasikvajpayee@rediffmail.com.

Larry Benjamin, DO, FRCS, FRCOphth, is in the Department of Ophthalmology at Stoke Mandeville Hospital, in Aylesbury, UK. Dr. Benjamin may be reached at larry.benjamin@btopenworld.com. He is a member of the CRSToday Europe Editorial Board.

Brian Little, MA, DO, FRCS, FRCOphth, is an Ophthalmologist at the Royal Free Hospital, in London. He may be reached at brianlittle@blueyonder.co.uk. Dr. Little is a member of the CRSToday Europe Editorial Board.