Background:The aim of the study is to raise the awareness of the influence of coma-like higher-order aberrations(HOAs)on power and orientation of refractive astigmatism(RA)and to explore how to account for that influe...Background:The aim of the study is to raise the awareness of the influence of coma-like higher-order aberrations(HOAs)on power and orientation of refractive astigmatism(RA)and to explore how to account for that influence in the planning of topography-guided refractive surgery in eyes with coma-like-aberrations-dominant corneal optics.Methods:Eleven eyes with coma-like-aberrations-dominant corneal optics and with low lenticular astigmatism(LA)were selected for astigmatism analysis and for treatment simulations with topography-guided custom ablation.Vector analysis was used to evaluate the contribution of coma-like corneal HOAs to RA.Two different strategies were used for simulated treatments aiming to regularize irregular corneal optics:With both strategies correction of anterior corneal surface irregularities(corneal HOAs)were intended.Correction of total corneal astigmatism(TCA)and RA was intended as well with strategies 1 and 2,respectively.Results:Axis of discrepant astigmatism(RA minus TCA minus LA)correlated strongly with axis of coma.Vertical coma influenced RA by canceling the effect of the with-the-rule astigmatism and increasing the effect of the against-the-rule astigmatism.After simulated correction of anterior corneal HOAs along with TCA and RA(strategies 1 and 2),only a small amount of anterior corneal astigmatism(ACA)and no TCA remained after strategy 1,while considerable amount of ACA and TCA remained after strategy 2.Conclusions:Coma-like corneal aberrations seem to contribute a considerable astigmatic component to RA in eyes with coma-like-aberrations dominant corneal optics.If topography-guided ablation is programmed to correct the corneal HOAs and RA,the astigmatic component caused by the coma-like corneal HOAs will be treated twice and will result in induced astigmatism.Disregarding RA and treating TCA along with the corneal HOAs is recommended instead.展开更多
文摘Background:The aim of the study is to raise the awareness of the influence of coma-like higher-order aberrations(HOAs)on power and orientation of refractive astigmatism(RA)and to explore how to account for that influence in the planning of topography-guided refractive surgery in eyes with coma-like-aberrations-dominant corneal optics.Methods:Eleven eyes with coma-like-aberrations-dominant corneal optics and with low lenticular astigmatism(LA)were selected for astigmatism analysis and for treatment simulations with topography-guided custom ablation.Vector analysis was used to evaluate the contribution of coma-like corneal HOAs to RA.Two different strategies were used for simulated treatments aiming to regularize irregular corneal optics:With both strategies correction of anterior corneal surface irregularities(corneal HOAs)were intended.Correction of total corneal astigmatism(TCA)and RA was intended as well with strategies 1 and 2,respectively.Results:Axis of discrepant astigmatism(RA minus TCA minus LA)correlated strongly with axis of coma.Vertical coma influenced RA by canceling the effect of the with-the-rule astigmatism and increasing the effect of the against-the-rule astigmatism.After simulated correction of anterior corneal HOAs along with TCA and RA(strategies 1 and 2),only a small amount of anterior corneal astigmatism(ACA)and no TCA remained after strategy 1,while considerable amount of ACA and TCA remained after strategy 2.Conclusions:Coma-like corneal aberrations seem to contribute a considerable astigmatic component to RA in eyes with coma-like-aberrations dominant corneal optics.If topography-guided ablation is programmed to correct the corneal HOAs and RA,the astigmatic component caused by the coma-like corneal HOAs will be treated twice and will result in induced astigmatism.Disregarding RA and treating TCA along with the corneal HOAs is recommended instead.
