RESUMEN
PURPOSE: To evaluate the benefit of the Holladay 2 formula versus the 3rd generation formulae in calculating the IOL power in eyes with non-standard axial length or keratometry before cataract surgery. PATIENTS: Retrospectiv study from January to December 2015. The inclusion critaeria were axial length (AL) <22mm or >26mm, or average keratometry <42 D or >46 D, dividing the patients in 4 groups respectively. The 7 parameters required to calculate the Holladay 2 formula were collected. The final refractive result was turned into spherical equivalent to calculate the optimal power retrospectively. Then, the results obtained using the other formulae were compared with the optimal IOL power. RESULTS: One hundred and twenty-six eyes operated by two surgeons were included. In the high AL group (n=32), the SRK/T was the most accurate formula; regarding the low AL group (n=36), the Hoffer Q and Holladay 2 formulae performed better; for the steep cornea group (n=27), the Hoffer Q, Haigis, Holladay 1 and 2 formulae were not different; last, the Holladay 1 and 2 were more accurate in the flat cornea group (n=33). CONCLUSION: In our study, the Holladay 2 formula does not seem to be better than the others for calculating IOL power in non-standard eyes. Preoperative eye features in such non-standard cases should be taken into account before the surgery to choose the more suitable formula.
Asunto(s)
Algoritmos , Ojo/patología , Lentes Intraoculares , Anciano , Antropometría , Femenino , Humanos , Masculino , Óptica y Fotónica , Refracción Ocular , Estudios RetrospectivosRESUMEN
PURPOSE: To evaluate and compare the predictability of different formulas for intraocular lens (IOL) power calculation using a new optical biometer (Aladdin). METHODS: This prospective cross-sectional study included 70 eyes of 70 patients who underwent uneventful phacoemulsification with IOL implantation. Preoperative IOL power calculations were performed using the Aladdin optical biometer. Postoperative actual refractive errors and errors predicted by the SRK/T, SRK II, Holladay 1, Hoffer Q and Haigis formulas were analyzed. The mean estimation error (EE), mean absolute estimation error (AEE) and the percentage of eyes within ± 0.50 and ± 1.00 D of the target refraction for each of five formulas were calculated and compared. This analysis was also repeated in three groups formed based on axial length (AL) (group 1: <22.5mm, group 2: 22.5-24 mm, group 3: >24 mm). RESULTS: In the overall study group, the smallest mean AEE was provided by the Holladay 1 formula, however there was no statistically significant difference in the mean AEE's predicted by the five formulas (P=0.34). The highest percentage of eyes within ± 0.50 and ± 1.00 D of the target refraction was also found by using Holladay 1 (71% and 97%). SRK/T provided smallest mean AEE for groups 1 (n=13) and 3 (n=16). In group 2 (n=41), the smallest mean AEE was obtained using Holladay 1. CONCLUSIONS: Based on the Aladdin biometric data used in our study, better results can be obtained using SRK/T formula in eyes with short or long AL. The Holladay 1 formula may be preferred in eyes with moderate AL.