title: Corneal toxicity secondary to inadvertent use of benzalkonium chloride preserved viscoelastic material in cataract surgery.
abstract: OBJECTIVE
  To study the long term toxic effects of intraocular benzalkonium chloride (BAC).
  
  
  METHODS
  19 patients exposed to intraocular BAC preserved viscoelastic during cataract surgery in February 1999 developed severe striate keratopathy immediately postoperatively. 16 patients, including two who underwent penetrating keratoplasty, were studied in the period April to June 2000. Ocular symptoms, visual acuity, biomicroscopy, intraocular pressure, dilated funduscopy, specular endothelial microscopy, and corneal pachymetry findings were recorded. The corneal and iris specimens of the two patients who underwent keratoplasty were studied by light, transmission, and scanning electron microscopy.
  
  
  RESULTS
  Six males and 10 females, aged 64-98 years, were studied 14-16 months postoperatively. All patients were symptomatic. 12 patients had best corrected visual acuity of 6/12 or better and four patients of between 6/18 and 6/60. Five patients had corneal epithelial oedema and 11 had Descemet's membrane folds. The central corneal thickness, 620 (SD 71) microm, in affected eyes was significantly higher (p<0.005, two tailed paired t test) than that of the contralateral eyes, 563 (SD 48) microm. The endothelial cell density was significantly lower (p<0.0001, two tailed paired t test) in affected eyes: 830 (SD 280) cells/mm2 v 2017 (SD 446) cells/mm2. The mean average cell area was significantly higher in the BAC treated eyes: 1317 (SD 385) microm2 v 521 (SD 132) microm2. There was no significant difference in the coefficient of variation of cell size between the two eyes (p=0.3, two tailed paired t test). Two corneal specimens displayed morphological features of bullous keratopathy and other non-specific abnormalities. Extracellular melanosomes were present in a portion of the iris of one case.
  
  
  CONCLUSIONS
  BAC is toxic to the corneal endothelium when used intraocularly, leading to severe striate keratopathy. This cleared in most cases but left varying degrees of residual stromal thickening in all eyes. If penetrating keratoplasty is required the results are excellent.
authors.affiliation: Sussex Eye Hospital, Eastern Road, Brighton BN2 5BF, UK.
authors.forename: H
authors.initials: H
authors.lastname: Eleftheriadis
authors.forename: M
authors.initials: M
authors.lastname: Cheong
authors.forename: S
authors.initials: S
authors.lastname: Sandeman
authors.forename: P P
authors.initials: PP
authors.lastname: Syam
authors.forename: P
authors.initials: P
authors.lastname: Brittain
authors.forename: G K
authors.initials: GK
authors.lastname: Klintworth
authors.forename: A
authors.initials: A
authors.lastname: Lloyd
authors.forename: C
authors.initials: C
authors.lastname: Liu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001548:Benzalkonium Compounds / Q000009:adverse effects*; D015331:Cohort Studies; D003316:Corneal Diseases / Q000139:chemically induced* / Q000503:physiopathology; D003902:Detergents / Q000009:adverse effects*; D005260:Female; D006490:Hemostatics / Q000627:therapeutic use; D006801:Humans; D065347:Hypromellose Derivatives; D008297:Male; D008747:Methylcellulose / Q000031:analogs & derivatives* / Q000627:therapeutic use; D008875:Middle Aged; D018918:Phacoemulsification / Q000009:adverse effects*; D014792:Visual Acuity
chemical_list: D001548:Benzalkonium Compounds; D003902:Detergents; D006490:Hemostatics; D065347:Hypromellose Derivatives; D008747:Methylcellulose