The Effects Of Three Different Sources Of Corneal Curvature On IOL Power Calculation In Traumatic Aphakic Eyes

Purpose: The purpose of this study is to compare the effects of three different sources of corneal curvature on secondary intraocular lens(IOL)power calculation in traumatic aphakic eyes.Methods: A clinical retrospective study of 239 patients treated for open-globe injuries were included.Demographics,details of corneal injuries,interval between injury and secondary IOL implantation,uncorrected/best corrected visual acuity(UCVA/BCVA)of before corneal sutures removal and at final visit,information of secondary IOL implantation,follow-up visit period,predictive refraction and postoperative achieved refraction were recorded.According to the difference of IOL power calculation,included patients were divided into three groups.IOL power calculation based on the corneal curvature of the healthy eye as group A,IOL power calculation based on the affected eye without corneal suture removal as group B,and IOL power calculation based on the affected eye with corneal suture removal as group C.The main outcome measures were mean absolute refractive error(MAE)calculated as the spherical equivalent and UCVA/BCVA improvement at the final follow-up visit.Multiple linear regression analysis was used to evaluate the relationships between presenting variables(including the effects of methods of IOL calculation,corneal wound involvement and severity of corneal injuries)and absolute refractive error as well as final UCVA.Results: UCVA and BCVA improvements were found in all three groups.Group C got the largest UCVA improvements(-1.10 ± 0.52 log MAR),followed by group B(-1.04 ±0.45 log MAR)and finally group A(-0.93 ± 0.44 log MAR).However,no significant difference showed among three groups(P=0.090).BCVA improvements were found in all three groups as well.Group C got the largest BCVA improvements(-0.65 ± 0.59 log MAR),followed by group A(-0.64 ± 0.57 log MAR)and finally group B(-0.48 ±0.56 log MAR).No significant difference showed among three groups(P=0.110).Group C(0.89 ± 0.85 D)got the smallest MAE,following by group B(1.31 ± 1.24 D)and group A(1.55 ± 1.29 D).Statistically significant difference was found between group A and group C(P<0.001).Multiple regression analysis demonstrated that severity of corneal injuries and three different methods of IOL calculation were risk factors for absolute refractive errors,and severity of corneal injuries was risk factor for UCVA at final visit.Compare to mild corneal injuries,moderate and severe corneal injuries obtain higher absolute refractive error(unstandardized coefficient = 0.599 and 1.295,P<0.001 respectively).IOL calculation based on the corneal curvature of the fellow eye and the injured eye without corneal sutures removal can cause higher absolute refractive error(unstandardized coefficient = 0.271 and 0.352,P= 0.200 and 0.044 respectively)than based on the injured eye after sutures removal.Moreover,compare to mild corneal injuries,moderate and severe corneal injuries obtain a worse final UCVA(unstandardized coefficient = 0.200 and 0.044,P=0.004 and 0.009 respectively).Conclusions: In penetrating ocular traumatic aphakic eyes,secondary IOL power calculation should base on the corneal curvature of the injury eye with corneal sutures removal is helpful in achieving better visual quality improvement and reducing the errors of IOL power calculation.