title: Evaluation of intraocular lens tilt with anterior segment optical coherence tomography.
abstract: OBJECTIVE
  To determine the ability of anterior segment optical coherence tomography (OCT) to detect intraocular lens (IOL) tilt evaluation in relation to the limbus.
  
  
  METHODS
  Observational case series.
  
  
  METHODS
  The IOL position of 123 eyes of 92 patients was examined with anterior segment OCT (Carl Zeiss Meditec, Dublin, California, USA). All eyes underwent uneventful phacoemulsification with the IOL in the bag. Images were obtained in 4 axes (180 to 0 degrees, 225 to 45 degrees, 315 to 135 degrees, and 270 to 90 degrees). Using MatLab software version 7.1 (Mathworks), the OCT images were analyzed. The distance between the iris margin and the anterior surface of IOL, the slope ratio between IOL and limbus, and the angle (θ; position of IOL with reference to the limbus) were determined and were correlated with the astigmatism and vision.
  
  
  RESULTS
  The mean slope of the limbus and the IOL in all axes was 0.003 ± 0.09 and -0.002 ± 0.12, respectively. The average slope ratio was 1.1 ± 1 (range, -2.09 to 3.82) and the angle (θ) was 1.52 ± 0.9 degrees (range, 0.04 to 3.6 degrees). The mean ocular residual astigmatism was 0.2379 ± 0.469 diopters. There was no significant correlation of ocular residual astigmatism with slope ratio (r = -0.171; P = .060) and slope angle (r = -0.132; P = .147). There was significant correlation of ocular residual astigmatism with total astigmatism (r=0.602, p=0.000). The mean distances between the iris margin and the anterior surface of IOL at the pupillary plane were 0.80 ± 0.6 mm and 0.83 ± 0.57 mm, respectively.
  
  
  CONCLUSIONS
  The normal in-the-bag IOL maintains an angle with reference to the limbus and a slope ratio without causing a significant tilt. Anterior segment OCT can be used as an alternative in IOL tilt evaluation by the analysis of its position in relation to the limbus.
authors.affiliation: Dr Agarwal's Eye Hospital and Eye Research Centre, Chennai, India.
authors.forename: Dhivya Ashok
authors.initials: DA
authors.lastname: Kumar
authors.forename: Amar
authors.initials: A
authors.lastname: Agarwal
authors.forename: Gaurav
authors.initials: G
authors.lastname: Prakash
authors.forename: Soosan
authors.initials: S
authors.lastname: Jacob
authors.forename: Yoga
authors.initials: Y
authors.lastname: Saravanan
authors.forename: Athiya
authors.initials: A
authors.lastname: Agarwal
mesh_terms: D000869:Anterior Eye Segment / Q000473:pathology*; D001251:Astigmatism / Q000175:diagnosis; D003941:Diagnostic Techniques, Ophthalmological; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D016850:Limbus Corneae / Q000033:anatomy & histology; D018918:Phacoemulsification; D011183:Postoperative Complications; D011475:Prosthesis Failure; D012029:Refraction, Ocular / Q000502:physiology; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology