Deviation Of The Axis And Its Affecting Factors After Implantation Of The Toric Implantable Collamber Lens

Objective:To assess the visual outcomes and deviation of the axis after implantation of Toric Implantable Collamer Lens (TICL) and analyses possible risk factors associated with rotational stability.Methods:27cases (46eyes) with high myopia complicated with moderate to high astigmatism were treated with TICL implantation. Before and after surgery, they underwent complete ophthalmologic examinations, such as manifest refraction, uncorrected visual acuity (UCVA), best corrected distance visual acuity (BCVA), intraocular pressure (ICP), Orbscan Ⅱ topography system and ultrasound biomicroscopy (UBM). Three months after surgery, a digital anterior segment photograph was taken to evaluate postoperative axis deviation from the intended axis, and UBM was used to observe the position of TICL.Results:Three months postoperatively, the efficacy and safety indexes were1.11±0.27and1.29±0.32, respectively; the mean cylinder was-0.47±0.38D, which had no significant difference with-0.48±0.50D one week postoperatively (P>0.05), but significantly decreased from-2.25±0.80D preoperative (P<0.05). The mean axis deviation degree three months postoperatively was5.63±5.59°(from0°to20°); vault observed by UBM was0.59±0.31mm and all footplates position were in situ. No statistically significant relationship was noted between gender and the direction of postoperative axis deviation (P>0.05, by chis-quare test) or deviation degree (P>0.05, by ANOVA). No statistically significant relationship was noted between the direction of intraoperative rotation and the direction of postoperative axis deviation (P>0.05, by chi-square test) or deviation degree (P>0.05, by ANOVA). Postoperative deviation degree was significantly correlated with the intraoperative rotation degree (r=-0.426, P <0.05) and age (r=0.312, P<0.05) by Spearman rank correlation. Only intraoperative rotation degree (β=-0.421) and age (β=O.305) significantly predicted postoperative deviation degree (adjusted R2=0.267, P<0.05) by multiple logistic regression analysis.Conclusion:TICL appears to be an effective and safe method for correction of myopic astigmatism and has good axis accuracy. Postoperative axis deviation degree might be related to intraoperative rotation degree and age.