Purpose A retrospective study were made to evaluate the accuracy of IOL power caculation formulain retrospective iris-claw IOL implantation compared with a foldable in-the-bag IOL insertion.
Material and Method Forty four  eyes of 41 patients that recieved retropupillary irs-claw IOLs implantations for correcting aphakia were included in group 1. Holiday I formula was selected in all cases when caculating the IOL power with a SF of 0.54. Thirty one eyes of 16 patients that recieved Rayner 630F acrylic lens in-the-bag insertion after regular phacoimulcification were included in group 2. The same formula was applied with a SF of 1,56. Post-operative refraction were examined after a minimum of 3 months after operations. The differences between the target refractive equivalent spherical diopters (SE) and the post-operative  menifested refractions were caculated and compared between 2 groups.
Results The mean target and menifested SE are -0,68D±0,70D and  -0,48D±1,12D in group 1 while 0,01D±0,17D and -0,15D±0,73D in group 2. T-test were performed in each group, but no statistical significant difference is found between the target and the SE in both group (P>0,05). The mean differences are 0,21D±0.82D and -0,16D±0,77D in each group respectively. No statistical significant difference is found between the 2 groups of differences.
Conclusion 1. Holiday I formula is a good choice for IOL caculation in retropupillary iris-claw fixation when the SF was selected as 0.54. 2. The post-operative SE of in iris-claw IOL fixation shows a trend of positive diopter shift compared with normal IOL in-the-bag insertion without statistical significance. 3. A larger group of samples should be included and a longer-term follow up should be made to come to a more convincing conclusion.