| Title | Optimized A-constant for a particular lens (XL-Stabi ZO, Carl Zeiss Meditec) and general avice for optimization and IOL calculations formulas |
| Purpose | To evaluate the efficacy of the Constant A given by the manufacturer of an aspheric IOL: evaluation of the difference between the subjective spherical equivalent 3 months post surgery and the target refraction. |
| Methods | 260 eyes from 8 surgical centers were enrolled in this study: 247 eyes received the study lens (XL Stabi ZO, Carl Zeiss Meditec). SRK/T formula was used in 71.7% of the cases. Patients were divided in 3 groups: short eyes (axial length (AL) < 22mm, normal eyes (22mm Data were collected at 1M and 3M. Deviation from intended refraction was calculated in all cases. |
| Results | The main efficacy criterion, the evaluation of the difference between the subjective spherical equivalent at 3M and the target refraction showed a slight undercorrection, with a mean value of -0.30D (SD: 0.61). In the short eyes group, -0.43D (SD: 0.76); in the normal eyes group -0.26D (SD: 0.56); in the long eyes group 0.36D (SD: 0.61). |
| Conclusion | The A Constant for the XL Stabi ZO should be adapted for short and long eyes, or another Formula should be used. |
| Last name | MATHYS |
| Initials | B |
| Department | Brussels Eye Specialists |
| City | Brussels |
| Last name | ALIO |
| Initials | J |
| Department | Instituto Oftalmologico de Alicante, Vissum Corporation |
| City | Alicante, Spain |
| Last name | MORBELLI |
| Initials | H |
| Department | Instituto Oftalmologico de Albacete, Vissum Corporation (Department of Refractive Surgery and Catara |
| City | Albacete, Spain |
| Last name | LEBRUN |
| Initials | T |
| Department | Clinique du Landy |
| City | Saint Ouen, France |
| Last name | KHAITRINE |
| Initials | L |
| Department | Clinique de Courlancy |
| City | Reims, France |
| Last name | RIECK |
| Initials | P |
| Department | Charité - Universitätsmedizin Berlin |
| City | Berlin, Germany |
| Last name | DEWILDE |
| Initials | F |
| Department | Eye Center Latem |
| City | Sint Martens Latem |
| Last name | TRABUCCHI |
| Initials | T |
| Department | Ospedale di Legnano |
| City | Legnano, Italy |