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A fixed dilated pupil following penetrating keratoplasty is a well recognised if rare postoperative complication. We report a case of Urrets-Zavalia syndrome following a deep lamellar keratoplasty (DLK). To our knowledge this association has not been previously described.
The mydriasis following penetrating keratoplasty was first described by Castroviejo (Castroviejo R, personal communication) but it was Urrets-Zavalia who first published his observations on a series of six cases and suggested an association of fixed dilated pupil, iris atrophy, and secondary glaucoma.1
The incidence of this syndrome is estimated at 5.8%, from pooled data on 445 eyes undergoing penetrating keratoplasty for keratoconus, of which 24 eyes developed a fixed dilated pupil.2 Davies and Ruben also found a similar incidence.3 However, other more recent studies find no cases,4–6 and some even question its continued existence. This may in part reflect improved surgical technique and differing diagnostic criteria.
The pupil can become abnormally dilated following penetrating keratoplasty for keratoconus, particularly if dilating drops are used. There are three main groups of pupillary dilatation.2
(1) A pupil with normal light and near reaction which is at least 1.5 mm larger than its fellow unoperated eye. It fully constricts with topical miotics. An incidence of approximately 90% has been reported for this type of abnormality.3
(2) An unreactive paretic pupil that returns slowly to normal.
(3) Irreversible pupil dilatation with iris atrophy.
This syndrome has also been reported when no dilating drops were used.2
In addition to the pupil and iris abnormalities, Urrets-Zavalia also described other features—iris ectropion, pigment dispersion, anterior subcapsular cataract and posterior synechiae. No early postoperative pressure rises were documented, although some had peripheral anterior synechiae and secondary glaucoma. Gasset also describes the glaucoma as a secondary phenomenon, commenting that it is not integral to the syndrome.2 In the series presented by Pouliquen et al, severe anterior uveitis, fibrinous exudate, and broad posterior synechiae are described.7 An early postoperative intraocular pressure rise is documented in two of the three cases presented by Tuft and Buckley.8
We describe the case of a patient undergoing deep lamellar keratoplasty for keratoconus who developed a permanently dilated pupil with iris atrophy. In addition she had marked anterior uveitis and posterior synechiae similar to the cases presented by Pouliquen et al.7 Dilating drops were not used.
A woman with keratoconus underwent a left deep lamellar keratoplasty at the age of 28 because of unstable contact lens fit and central corneal scarring. A 7.75 mm graft into a 7.5 mm diameter recipient DLK was performed under peribulbar anaesthesia with sedation. Disposable Baron Hessburg suction trephines were used and the deep lamellar dissection performed after air injection, as described by Tuft and Buckley.9 A paracentesis was performed and no viscoelastic or air was injected into the anterior chamber. The procedure was uncomplicated.
In her medical history of note was atopic eczema and hay fever.
The eye became painful during the first postoperative evening. At the first dressing the next morning she was comfortable again but the pupil was noted to be semidilated with an intraocular pressure of 10 mm Hg. The anterior chamber was deep and quiet.
Three weeks postoperatively, despite using her topical steroids, she developed a marked anterior uveitis with posterior synechiae to the lens. This responded well to an increase in her topical steroids. However, the iris has remained fixed, dilated, and non-reactive.
The visual acuity at 1 month postoperatively was 6/9+ with −1.75/−1.50 × 125. Unfortunately 11 weeks postoperatively she developed an inferior retinal detachment. No breaks were identified but she underwent a cryobuckle procedure with an encircling band. Six months after her initial surgery she sees 6/12 wearing a contact lens correction of −2.25/−3.50 × 65. She is still troubled by glare and is somewhat unhappy with the cosmetic appearance of the eye.
The precise aetiology of this syndrome is unknown; it has been suggested that iris ischaemia can develop if it is compressed between the lens and cornea during surgery.3 This cannot be the explanation in patients undergoing deep lamellar keratoplasty. Urrets-Zavalia syndrome has also been described after penetrating keratoplasty for other indications3 and after cataract surgery.
Urrets-Zavalia suggested that the strong mydriasis produced by atropine at the time of surgery brought the iris into contact with the peripheral cornea to produce peripheral anterior synechiae and glaucoma.1 Davis and Ruben noted the condition was more common in the absence of a peripheral iridotomy and proposed a mechanism of relative pupil block.3 Naumann comments that in over 1000 cases of penetrating keratoplasty he has never seen this condition and suggests that performing a peripheral iridotomy in phakic patients is protective.4 Interestingly he always uses dilating drops.
It has been suggested that the iris is in some way abnormal in keratoconus, supported by the observation that these pupils remain dilated for longer periods following mydriasis than in normal eyes.2 Keratoconic eyes seem to hyperreact to application of mydriatics as far as speed of dilation and duration of effect, this observation is also seen the eyes of patients with Down's syndrome.2
An abnormality of the sympathetic nervous system in the keratoconic eye remains unproven.
Davies and Ruben also suggest that direct iris trauma during surgery could result in strangulation of iris vessels in the mid-periphery and ischaemic paralysis of the sphincter pupillae.3
Tuft and Buckley suggest in the presence of raised intraocular pressure, the low ocular rigidity of the keratoconic eye permits occlusion of the vessels at the root of iris within the sclera, which results in iris ischaemia while preserving ciliary body function.9
This case, the first to our knowledge, describes the Urrets-Zavalia syndrome following a lamellar keratoplasty. The compressive theory cannot play a part in this instance and it may lend support to the theory of an intrinsic iris abnormality in keratoconus. Equally, the pain she experienced on the first postoperative evening may have been secondary to raised intraocular pressure and perhaps supports the ischaemic theory.9 In either case, this syndrome is still poorly understood.