Abstract
Purpose :
Preoperative anterior chamber depth (ACD) is one of the most important factors that should be considered before implantation of iris-fixated phakic intraocular lenses (pIOL). Different safe levels of ACD have been proposed before. Even applying the proposed levels, considerable number of patients still suffering from long term endothelial cell complications, that means the optimal level has not been introduced yet. The purpose of this study is to evaluate the long term change of endothelial cell density (ECD) and its correlation with preoperative ACD in patients with pIOL.
Methods :
A total of 90 eyes from 57 patients who underwent pIOL implantation for correcting myopia and/or astigmatism between 2000 and 2007 were retrospectively enrolled. Significant endothelial cell loss (SECL) was defined as having corneal edema and/or ECD ≤1500 cells/mm2 and/or endothelial cell loss (ECL) ≥30% from the baseline on the last follow up visit. Risk factors for SECL were evaluated. Correlation between ACD and ECL was investigated.
Results :
Average follow up time was 11.8 ± 2.0 years (range; 9.1 to 17.3 years). In comparison to preoperative measurements, mean ECL (adjusted for age) at the last follow up was -22 ± 25% (range; -79 to 17%) (p<0.001). Mean percentage of adjusted ECL in Eyes with preoperative ACD ≤3.20 mm (-54% ± 18%; range -79% to -5%), 3.21-3.49 mm (-15% ± 17%; range -52% to 0%) and ≥3.50 mm (-5 ± 9%; range; -23% to 16%) were statistically significant (p<0.001). No eyes with ACD ≥3.50 mm had SECL, while 53% of the eyes with ACD 3.21-3.49 mm reached SECL (p<0.001). Of the eyes with ACD ≤3.20 mm, 94% experienced SECL. There was significant negative correlation between ECL and preoperative ACD (r = -0.70, p<0.001). Younger age [OR (95% CI) =0.89 (0.83 – 0.94); p=0.001] and shallower preoperative ACD [OR (95% CI) = 12.50 (3.83 – 41.75); p<0.001] were risk factors for SECL in multivariate analysis. Receiver operating characteristic (ROC) curve analysis revealed that the cutoff point of 3.35 mm for preoperative ACD can provide 84% sensitivity and 88% specificity.
Conclusions :
There was significant negative linear correlation between preoperative ACD and ECL over the long term follow up. This study revealed that for the better long term safety, minimum preoperative ACD ≥ 3.2 mm that recommended by the manufacturer and previous studies should be reconsidered.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.