Abstract
Purpose :
Methods evaluating rotational stability of intraocular lenses (IOL) differ among the majority of present studies. The aim of this study was to assess the intra-, interrater-reliability and short-term reproducibility of a custom made semi automated software program evaluating postoperative IOL rotation.
Methods :
Rotix is a custom built program based on LabView (National Instruments, Texas, USA) to evaluate IOL position in the eye. The program automatically calculates the angle between a manually drafted axis connecting the IOL markings and an axis between two episcleral vessels (reference axis).
To assess the intra- and interrater reliability, a series of 25 pictures documenting the axis of IOLs on 2 subsequent time points was used. All pictures were evaluated three times by two experienced graders (DS, LS) in a randomized order. Short-term reproducibility was assessed evaluating a series of 10 different IOL pictures taken 3 times in one visit.
Results :
The mean difference of measured angles evaluating 75 pictures between grader 1 (G1) and grader 2 (G2) was 0.06 ± 0.28 degrees. The intraclass-correlation-coefficient (ICC) between G1 and G2 = 0.95. Intrarater- reliability ICCs were similar for both graders (ICC G1= 0.97, ICC G2= 0.96). The ICC for short-term reproducibility was 0.99. Mean standard deviation between the measurements was 0.26 degrees. The maximum absolute difference between measurements per triplet ranged between 0.22 and 1.16 (median= 0.41) degrees.
Conclusions :
Evaluation of IOL rotation with Rotix showed excellent intra- and interrater reliability. Furthermore, short-term reproducibility of this method, which is independent from head tilt or cyclotorsion, showed reliable results. Ocular reference points such as episcleral vessels or Axenfeld loops should be used in future studies investigating rotational stability of IOLs.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.