The fixed dilated pupil after cataract surgery--is it related to intraocular use of hypromellose?

Abstract

Hypromeliose can be used as a viscoelastic substance during cataract surgery. Two-groups of patients, one group operated on using hypromeliose, the other using sodium hyaluronate as a viscoelastic substance were followed up 2-6 months postoperatively. A total of 16.7% of the eyes operated on using hypromeliose developed a non-reactive semidilated pupil whereas none ofthe eyes from the control group developed this phenomenon. However, it has been noted in our practice that some pupils of eyes operated on with hypromellose 2% used as the viscoelastic substance developed abnormalities in pupil reaction; a number of patients developed a fixed, semi-dilated pupil postoperatively (Figs 1 and 2) resulting in glare, poor quality of vision, as well as cosmetic embarrassment. We have since stopped using hypromellose as a result of these complications. This paper presents a retrospective study comparing the incidence of pupil abnormality in eyes operated on using hypromellose as viscoelastic with a consecutive batch of similar operations performed prospectively by the same surgeon (RCH) using sodium hyaluronate (Healon).Although to our knowledge, there has been no report on the effect of intraocular use of hypromellose on pupil mobility in the ophthalmic literature to date, we were so concerned by our clinical findings that we did not consider it ethical to perform a prospective study using hypromellose. Subjects and methodsFigure I Non-reactive, semidilated pupil in one ofthe eyes operated on using hypromellose 2% as viscoelastic.

Update and review of Urrets-Zavalia syndrome

“…Prophylactic iridectomy or YAG laser iridotomy a few days prior to surgical intervention appear to have efficacy in decreasing risk of pupillary block (2,9,46) . However, this practice remains controversial, and some authors have reported that these therapies provide no benefit (11) . Careful management of surgical equipment, such as trephines and scissors, may also prevent iris damage (8) .…”

“…Other findings of UZS were subsequently reported, including peripheral synechiae, posterior subcapsular opacity, iris ectropion, pigmentary dispersion, and glaukomflecken (3)(4)(5)(6)(7)(8)(9)(10)(11) . Other procedures shown to be associated with UZS include trabeculectomy (TREC) (5) , deep anterior lamellar keratoplasty (DALK) (12)(13)(14)(15) , Descemet-stripping automated endothelial keratoplasty (DSAEK) (16)(17)(18) , cataract surgery (11,19) , goniotomy (20) , phakic intraocular lens implant (IOL) (21)(22)(23) , argon laser peripheral iridoplasty (ALPI) (7) , and octafluoropropane injection (C3F8) (24) . Although the reported incidence of UZS is low, the associated visual symptoms can cause limitations in activities of daily life requiring preventative measures by ophthalmic surgeons (7,14) .…”

“…Intraocular pressure (IOP) elevation, with or without pupillary block, has been implicated as the trigger mechanism of UZS (4,27) . Use of viscoelastic substances during surgery have been suspected as toxic to the iris sphincter and a cause of acute rises in IOP (10,11) . The use of miotics before and during surgery has been considered prophylactic by some authors and a risk factor of pupillary atrophy by others (4,10,18,25,28) .…”

Pupil size before and after phacoemulsification in nondiabetic and diabetic patients

“…10,11 In particular, a fixed dilated pupil occurs in some cases after intracapsular and extracapsular cataract extraction. [12][13][14][15][16] Furthermore, Koch et al 17 report that postoperative pupil size cannot be predicted with sufficient consistency by preoperative size. Thus, because the changes in pupil size and shape after cataract surgery were significant with the use of earlier surgical techniques and medications, it was difficult to select which patients were most appropriate for multifocal IOL implantation.…”

Pupil size and reactivity following hydroxypropyl methylcellulose and sodium hyaluronate.

“…These figures are much lower than those of Tan and Humphrey who found 27.8% of pupils in the HPMC group and 18.7% of pupils in the Healonid group partially reactive following surgery. 7 One explanation for these differences could be in the type of surgery. Our surgery (102 out of 106 cases) was performed using phacoemulsification whereas their surgery was entirely extracapsular cataract extraction.…”