Copenhagen 2016 Registration Programme Exhibitor Information Virtual Exhibition Satellite Meetings Glaucoma Day 2016 Hotel Star Alliance

10 - 14 Sept. 2016, Bella Center, Copenhagen, Denmark

This Meeting has been awarded 27 CME credits


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Analysis of postoperative alignment error of toric intraocular lenses by ray-tracing aberrometry and slit lamp, and its correlation with visual outcome

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Session Details

Session Title: Presented Poster Session: Toric IOLs I

Session Date/Time: Saturday 10/09/2016 | 09:30-11:00

Paper Time: 10:00

Venue: Poster Village: Pod 4

First Author: : R.Chaudhuri INDIA

Co Author(s): :    N. Shroff   G. Singh   R. Dutta   A. Koul   S. Jyoti  

Abstract Details


To analyze post-operative Toric IOL alignment error and rotation by two methods, Ray Tracing Aberrometry and Slit Beam method and its correlation with visual outcome, as well as to evaluate whether the Ray Tracing method is superior to the Slit Beam method.


Cataract & IOL Service, Shroff Eye Centre, A-9 Kailash Colony, New Delhi, India 110048


50 eyes with cataract and corneal astigmatism (1.00 to 4.00 D) underwent micro-incision cataract surgery with AcrySof Toric intraocular lens implantation. The desired axis of implantation was calculated using the online AcrySof Toric Calculator. All eyes were examined on postoperative days 1, 7, 30 and 90 and assessed for uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA) and residual astigmatism. Toric IOL axis was determined by ray tracing aberrometry (I-TRACE Visual Function Analyser) through an undilated pupil, and by aligning a narrow slit lamp beam to the toric IOL axis marks with the pupil dilated.


Mean postoperative alignment error day-90 was 4.10±2.59 degrees (slit beam) and 4.78±2.32 degrees (I-TRACE) (p=.207). Mean absolute post-operative rotation between day-7 and day-90 was 0.8±2.1° (slit beam) and 1.72±1.57° (I-TRACE) (p=.021). The slit beam method showed no rotation in 43 cases (86%) whereas the I-TRACE method showed no rotation in only 7 cases (14%). The mean LogMAR UCVA on day-90 was 0.15±0.16. The mean residual cylinder on day-90 was 0.60±0.41 diopters. The correlation between misalignment and UCVA on day-90 was weak by both methods (Slit Beam r=0.083, I-TRACE r=-0.254). Likewise, the correlation between misalignment and residual astigmatism on day-90 was weak by both methods (Slit Beam r=0.299, I-TRACE r=-0.055).


Ray Tracing and Slit Beam methods are comparable for assessing Toric IOL alignment post-operatively. Although, Ray Tracing is more sensitive (1° steps) as compared to Slit Beam (5° steps), it does not have any clinically significant bearing on visual outcome, since slight misalignment and small residual refractive errors are well-tolerated by patients. Therefore the Slit-lamp is a cheap and efficient alternative to the I-TRACE for assessing the alignment of Toric IOLs. In cases with significant residual cylinder with no significant alignment error of the IOL, the effect of the posterior corneal curvature might have had a role to play.

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