Alpins and thibos vectorial astigmatism analyses: proposal of a linear regression model between methods

Revista Brasileira de Oftalmologia

Giuliano De Oliveira Freitas²  Joel Edmur Boteon¹  Mario Jose Carvalho¹  Rogerio De Melo Costa Pinto¹ 

[1] ,Instituto de Saúde Ocular Cataract Surgery Department Uberlândia MG ,Brazil

关键词: Phacoemulsification;    Astigmatism;    Limbus corneae;    Lens implantation;    intraocular;    Diagnostic techniques;    ophthalmological;    Facoemulsificação;    Astigmatismo;    Limbo da córnea;    Implante de lentes intraoculares;    Técnicas de diagnóstico oftalmológico;   

DOI  :  10.1590/S0034-72802013000500005

来源: SciELO

【 摘 要 】

PURPOSE: To determine linear regression models between Alpins descriptive indices and Thibos astigmatic power vectors (APV), assessing the validity and strength of such correlations. METHODS: This case series prospectively assessed 62 eyes of 31 consecutive cataract patients with preoperative corneal astigmatism between 0.75 and 2.50 diopters in both eyes. Patients were randomly assorted among two phacoemulsification groups: one assigned to receive AcrySof®Toric intraocular lens (IOL) in both eyes and another assigned to have AcrySof Natural IOL associated with limbal relaxing incisions, also in both eyes. All patients were reevaluated postoperatively at 6 months, when refractive astigmatism analysis was performed using both Alpins and Thibos methods. The ratio between Thibos postoperative APV and preoperative APV (APVratio) and its linear regression to Alpins percentage of success of astigmatic surgery, percentage of astigmatism corrected and percentage of astigmatism reduction at the intended axis were assessed. RESULTS: Significant negative correlation between the ratio of post- and preoperative Thibos APVratio and Alpins percentage of success (%Success) was found (Spearman's ρ=-0.93); linear regression is given by the following equation: %Success = (-APVratio + 1.00)x100. CONCLUSION: The linear regression we found between APVratio and %Success permits a validated mathematical inference concerning the overall success of astigmatic surgery.

【 授权许可】

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