Corneal Spherical Aberration Before And After Cataract Surgery And Customisation Of Intraocular Lens Asphericity

PartⅠ:Analysis of corneal spherical aberration in patients before and after cataract surgeryObjectiveTo investigate the distribution and the change of corneal spherical aberration(SA) in the age-related cataract patients before and after the cataract surgery.Methods155 eyes of 93 patients with age-related cataract were included. All eyes received a comprehensive ophthalmologic examination.Corneal SA was measured by using a Scheimpflug photography system (Pentacam). All patients were followed up to 3 months.ResultsThe mean corneal SA before and after the 3.2 mm incision cataract surgery for 6mm diameter was (0.294±0.138)μm and (0.271±0.130)μm respectively. There was statistical difference between them (P<0.05, t=4.384); There was no difference between the corneal SA of male and female (t=-0.418, P=0.676).There exhibited a linear positive correlation between corneal SA and age (r=0.203, P< 0.003).ConclusionThe corneal SA varied greatly among cataract eyes. There was no difference between corneal SA of male and female.Patients' corneal SA has negative trend after 3.2 mm incision cataract surgery surgery. Corneal SA increases slightly with age. Customized aspheric intraocular lenses are needed. Part II:Customisation of intraocular lens asphericity based on corneal spherical aberationObjectiveTo compare the quality of vision of patients with customised aspheric intraocular lenses (IOL) versus patients were implantated with aspheric IOL randomized after a 3.2 mm incision cataract surgery.Methods55 patients(94 eyes) were divided into two groups:47 eyes (reference group) received Akreos Adapt Advanced Optics (AO, Bausch & Lomb, Inc.) and the Tecnis ZA9003 (Advanced Medical Optics,Inc) randomizedly and 47 eyes received a customised-aspheric IOL. The target postoperative total wavefront spherical aberration was set at the range of zero to 0.3μm. Thus, for corneal spherical aberration <+0.3μm, the AO was selected; The corneal spherical aberration≥+0.3μm, the Tecnis ZA9003 was selected. Best corrected visual acuity (BCVA), contrast sensitivities(CS), glare contrast sensitivities(GS) and ocular wavefront aberrations were analysed 3 months after cataract surgery.ResultsPostoperative BCVA was similar in both groups (P=0.308). Mesopic CS were significantly better in the custom group at intermediate and high spatial frequencies (p<0.05). Mesopic GS were significantly better in the custom group at high spatial frequencies (p<0.05), while photopic contrast sensitivities were similar. Total SA was no difference between custom group and reference group.ConclusionIndividual selection of IOL asphericity with a preoperative corneal SA measurement allowed control of final ocular SA. Such customisation improves mesopic CS, mesopic GS and leads to better objective quality of vision. Part III:Evaluation of the consistency between the measured value and estimate value of ocular spherical aberration after Individual selection of aspherical IOLObjectiveTo explore the consistency between the measured value and estimated value of total spherical aberration after individual selection of aspherical intraocular lens (IOL) in order to evaluate the feasibility of individual selection of aspherical IOL based on using a Scheimpflug photography system (Pentacam) to measure corneal spherical aberrationMethods82 eyes of 47 patients with age-related cataract were included. All eyes received a comprehensive ophthalmologic examination.Corneal SA was measured by using a Scheimpflug photography system.45 eyes received Akreos Adapt advanced Optics (AO,Bausch & Lomb, Inc.),37 eyes received the Tecnis ZA9003 (Advanced Medical Optics,Inc) and all eyes were estimated the value of ocular spherical aberration.The ocular spherical aberration were measured 3 months after cataract surgery.ResultsThe estimated value and measured value of ocular spherical aberration was (0.189±0.151) (μm, the is (0.141±0.131)μm respectively, indicating statistical difference between them (t=5.347, P<0.01). However, There exhibited a positive linear correlation between the results of two value(r=0.846, P<0.01). The Bland-Altman method showed the consistency between the measured value and estimate value of ocular spherical aberration.ConclusionThe estimated value presents some different results from measured value of ocular spherical aberration, whereas the statistical analysis showed the consistency between two values. Individual selection of aspherical IOL based on using Pentacam to measure corneal spherical aberration was feasible.