title: Effect of the angle of the operating microscope light beam on visual recovery after phacoemulsification: Randomized trial.
abstract: OBJECTIVE
  To evaluate differences in visual recovery after phacoemulsification with direct or tilted surgical microscope illumination using a macular photostress test.
  
  
  METHODS
  Western Eye Hospital, Imperial College Health Care National Health Service Trust, London, United Kingdom.
  
  
  METHODS
  This randomized double-masked controlled trial enrolled patients presenting to a daycare unit for single-eye cataract surgery. Inclusion criteria were no ocular pathology other than cataract, corneal keratometric astigmatism less than 1.50 diopters, intended target of emmetropia in the operated eye, and cataract grade 1 to 3 (Lens Opacification Classification System II). Exclusion criteria were an abnormal preoperative photostress test. Patients were randomized to have phacoemulsification with the operating microscope angled 15 degrees nasal to the fovea (study group) or with the operating microscope directly overhead around the optic disc region (control group). The same surgeon performed all phacoemulsification procedures using a standardized technique and topical anesthesia. Outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuity 10 minutes and 60 minutes postoperatively.
  
  
  RESULTS
  In the 30 patients evaluated, the mean UDVA 10 minutes postoperatively was 0.40 logMAR +/- 0.26 (SD) in the study group and 0.72 +/- 0.36 logMAR in the control group (P<.01). The mean CDVA was 0.18 +/- 0.26 logMAR and 0.44 +/- 0.30 logMAR, respectively (P = .016). There was no significant between-group difference in acuity at 60 minutes.
  
  
  CONCLUSIONS
  Tilting the microscope beam away from the fovea resulted in faster visual recovery and less macular photic stress.
  
  
  BACKGROUND
  No author has a financial or proprietary interest in any material or method mentioned.
authors.affiliation: Moorfields Eye Hospital, London, United Kingdom. harmanfran@hotmail.com
authors.forename: Francesca E
authors.initials: FE
authors.lastname: Harman
authors.forename: Melanie C
authors.initials: MC
authors.lastname: Corbett
authors.forename: Julian D
authors.initials: JD
authors.lastname: Stevens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D019654:Lens Implantation, Intraocular; D008029:Lighting / Q000379:methods*; D008297:Male; D008853:Microscopy / Q000295:instrumentation; D008875:Middle Aged; D009873:Operating Rooms; D018918:Phacoemulsification; D011184:Postoperative Period; D011446:Prospective Studies; D020127:Recovery of Function / Q000502:physiology*; D012160:Retina / Q000503:physiopathology* / Q000528:radiation effects; D013997:Time Factors; D014792:Visual Acuity / Q000502:physiology*