title: Urrets-Zavalia syndrome following penetrating keratoplasty for keratoconus.
abstract: BACKGROUND
  Urrets-Zavalia syndrome (UZS) consists of a fixed dilated pupil associated with iris atrophy. It is a poorly understood complication following penetrating keratoplasty (PKP) for keratoconus (KC). In this work, we aim to establish the incidence, visual outcomes, and an understanding of UZS.
  
  
  METHODS
  This was a retrospective single-center study in a tertiary eye service in the United Kingdom of consecutive patients with UZS following PKP for KC in a 10-year period. Post-operative complications, including raised intraocular pressure (IOP), were recorded. UZS patients and age-matched control patients who had undergone PKP for KC without developing UZS attended a comprehensive clinical assessment. Anterior segment indocyanine green (ICG) angiography assessed iris perfusion.
  
  
  RESULTS
  The incidence of UZS was 16.2 %. There was no difference in LogMAR VA or Pelli-Robson contrast sensitivity between groups. There was higher first-day post-operative IOP in UZS (p = 0.02). UZS patients had increased pupil size (p = 0.09) with reduced response to pilocarpine 2 % (p < 0.001). ICG angiography revealed delayed/reduced iris vasculature filling in UZS compared with normal filling patterns of controls.
  
  
  CONCLUSIONS
  Elevated post-operative IOP within 24 h was a significant factor in the development of UZS. Visual function in UZS patients was unaffected. UZS patients developed longstanding mydriasis with reduced reactivity to topical pilocarpine 2 %. ICG angiography confirmed iris vessel ischemia; supporting the theory that iris ischemia resulting from occlusion of iris root vessels due to elevated IOP causes UZS. We advocate rigorous intraoperative management of ocular viscoelastic devices and aggressive postoperative IOP control in patients undergoing PKP for KC.
authors.affiliation: Department of Ophthalmology, Royal Liverpool University Hospital, Liverpool, UK.
authors.forename: Gustavo S
authors.initials: GS
authors.lastname: Figueiredo
authors.forename: Sai S P
authors.initials: SS
authors.lastname: Kolli
authors.forename: Sajjad
authors.initials: S
authors.lastname: Ahmad
authors.forename: Kevin
authors.initials: K
authors.lastname: Gales
authors.forename: Francisco C
authors.initials: FC
authors.lastname: Figueiredo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001284:Atrophy; D004396:Coloring Agents; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D015994:Incidence; D007208:Indocyanine Green; D007429:Intraocular Pressure; D007498:Iris / Q000098:blood supply* / Q000473:pathology*; D007511:Ischemia / Q000209:etiology*; D007640:Keratoconus / Q000601:surgery*; D015948:Keratoplasty, Penetrating / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D015878:Mydriasis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D011183:Postoperative Complications; D012189:Retrospective Studies; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green