Duration 5min, Q&A 3min
Performance of Spherical Versus Aspherical Intra-Ocular Lenses in Asian (Japanese Community Living in Brazil) and Caucasian Eyes
Analyze optical characteristics and performance of Spheric and Aspheric IOLs in Asian and Caucasian eyes for visual quality restoration after cataract surgery
A prospective, randomized, interventional clinical trial was conducted. Patients were primarily divided according to their ethnical phenotype into Asians and Caucasians. A randomization schedule generated by a biostatistician was used to divide patients into four sub-groups.
The analyzed variables were manifest refraction, best corrected and uncorrected visual acuities, wavefront aberrations with special attention to corneal, internal and ocular Z(4,0), spherical aberrations RMS values and total spherical Strehl Ratio. We performed comparisons between groups using mixed models to account for correlation between eyes. For subgroup comparisons, we used general linear models. A P value less than 0.05 was considered statistically significant.
Results and Conclusion
The Asian group consisted in 70 eyes (31 with SN60WF and 39 with SN60AT implantation) and the Caucasian group counted with 33 eyes (16 with SN60AT and 17 with SN60WF). The gender distribution was equal in both groups, being 45.2% and 51.1% of males, respectively in Asian and Caucasian groups (P=0.52). Preoperative refraction spherical equivalent were -0,69D and -1,39D (P=0.41). Higher-order aberrations were similar in both groups (0.802μm and 0.905μm, respectively, P =0.18). Preoperative corneal Z(4,0) were 0.375μm and 0.232μm, respectively in Asians and Caucasians (P=0.33). Postoperatively, either Asian or Caucasian eyes implanted with asphericIOLs showed significantly fewer amounts of spherical aberrations RMS (0.212 μm with asphericIOLs versus 0.308 μm with spherical IOLs in Asian eyes, P<0.01; and 0.115 μm versus 0.383 μm in Caucasian eyes, P<0.01). The internal Z(4,0) were significantly more negative in eyes with asphericIOLs, independently of the ethinicity (-0.359 μm with aspherical IOLs versus -0.134 μm with spherical IOLs in Asian eyes, P<0.01; and -0.219μm versus 0.115 μm in Caucasian eyes, P<0.01). Overall ocular Z(4,0) were lower in eyes implanted with asphericIOLs, still contrarily of the difference found in Caucasian eyes, in which total Z(4,0) were 0.009μm in eyes with asphericIOLs versus 0.340μm in eyes with spheric IOLs (P<0.01), in Asian eyes such difference was not significant (0.087μm versus 0.209μm, P=0.12).
Spherical aberration related Strehl Ratio was significantly better in eyes with asphericIOLs in both groups.The aspheric IOL fulfills its proposal in decreasing ocular spherical aberrations, and as consequence, better values of Strehl ratio were found in eyes implanted with such IOLs. However, different aspherical platform might be proposed for Asian eyes in order to get even better visual quality results for this population.
[ Keyword ]
Ethnicity / Aspheric intra-ocula lens / Visual performance / Asian eyes
[ Conflict of Interest ]