Mehmet Icoz, Burak Tanriverdi, Mehmet Yakin
A systematic hyperopic shift was observed with all formulas after YISF.Although SRK/T,BUII,and EVO 2.0 appeared more successful before optimization,third-generation and modern formulas demonstrated similar refractive performance after constant optimization.These findings suggest that refractive outcomes are largely influenced by surgery-related variability in actual lens position.
PURPOSE: To evaluate the refractive predictability of third-generation and modern intraocular lens(IOL)power calculation formulas in eyes undergoing Yamane intrascleral fixation(YISF).
DESIGN: Retrospective,comparative evaluation of IOL power calculation accuracy.
SUBJECTS: Eighty-seven eyes of 87 patients who underwent YISF due to aphakia or single-piece IOL subluxation were evaluated.
METHODS: Third-generation formulas(Hoffer Q,Holladay 1,Sanders Retzlaff Kraff/Theoretical(SRK/T),and T2) and modern formulas(Barrett Universal II[BUII] and emmetropia verifying optical[EVO] 2.0)were assessed.
MAIN OUTCOME MEASURES: Mean prediction error(ME),mean absolute error(MAE),median absolute error(MedAE),and the proportions of eyes with ME within ±0.50D and ±1.00D were calculated.Analyses were performed before and after constant optimization.The constant optimization was performed using the method of zeroing the ME.
RESULTS: In the initial analysis,all formulas demonstrated a hyperopic shift,with ME values ranging from +0.55D to +0.71D.No significant differences were detected among the formulas in terms of ME,MAE,or MedAE(p>0.05).The proportion of eyes with ME within ±0.50D was higher for SRK/T(63%),BUII(60%),and EVO 2.0(54%) than for Hoffer Q(48%) (p<0.001,p<0.001,andp=0.004).In contrast,no significant difference was found in the proportion of eyes with ME within ±1.00D(p>0.05).After constant optimization,ME reached zero for all formulas,and no significant differences were observed among the formulas regarding MAE,MedAE,or the proportions of eyes with ME within ±0.50D and ±1.00D(p>0.05).In both analyses,no statistically significant differences were found among the six formulas with respect to either IOL type or indication(p>0.05).
CONCLUSION: A systematic hyperopic shift was observed with all formulas after YISF.Although SRK/T,BUII,and EVO 2.0 appeared more successful before optimization,third-generation and modern formulas demonstrated similar refractive performance after constant optimization.These findings suggest that refractive outcomes are largely influenced by surgery-related variability in actual lens position.