![]() Corneal decentration relative to pupil center has significant effects on oblique astigmatism, horizontal coma, and horizontal trefoil. Conclusions: Corneal and lenticular aberration magnitudes are similar, and aberrations of the anterior corneal surface are approximately three times those of the posterior surface. An object at infinity, rather than at the image in the anterior cornea, gave incorrect aberration estimates of the posterior cornea. Corneal topographic centers were displaced from aberrometer pupil centers by 0.32 ± 0.19 mm nasally and 0.02 ± 0.16 mm inferiorly disregarding corneal decentration relative to pupil center was significant for oblique astigmatism, horizontal coma, and horizontal trefoil. Anterior corneal aberrations were approximately three times higher than posterior corneal aberrations and usually had opposite signs. Most correlations between lenticular and ocular parameters were positive and significant, with compensation of total corneal aberrations by lenticular aberrations for 5/12 coefficients. Results: Apart from defocus, the highest aberration coefficients were horizontal astigmatism, horizontal coma, and spherical aberration. Theoretical raytracing investigated influence of object distance on aberrations. Lenticular contributions were given as differences between ocular and corneal aberrations. Raytracing through models of corneas provided total corneal and surface component aberrations for 5-mm-diameter pupils. Anterior and posterior corneal topographies were obtained with an Oculus Pentacam, and ocular aberrations were obtained with an iTrace aberrometer. Methods: There were 61 healthy participants with ages ranging from 20 to 55 years and refractions −8.25 diopters (D) to +3.25 D. h Positive linear correlations between posterior corneal astigmatism and posterior corneal LOA RMS in eyes with WTR anterior corneal astigmatism ( r 2 = 0.265, N = 852).Purpose: To determine the corneal surfaces and lens contributions to ocular aberrations. g Positive linear correlations between posterior corneal astigmatism and posterior corneal LOA RMS ( r 2 = 0.172, N = 1976). f Positive linear correlations between posterior corneal astigmatism and posterior corneal aberration in eyes with WTR anterior corneal astigmatism ( r 2 = 0.259, N = 852). e Positive linear correlations between posterior corneal astigmatism and posterior corneal aberration ( r 2 = 0.172, N = 1976). d Weak positive linear correlations between anterior and posterior corneal astigmatism in eyes with oblique anterior corneal astigmatism ( r 2 = 0.074, N = 405). c Weak negative linear correlations between anterior and posterior corneal astigmatism in eyes with ATR anterior corneal astigmatism ( r 2 = 0.014, N = 719). b Positive linear correlations between anterior and posterior corneal astigmatism in eyes with WTR anterior corneal astigmatism ( r 2 = 0.298, N = 852). Also, the posterior corneal aberration was also essential in clinics.Ī Positive linear correlations between the magnitude of anterior and posterior corneal astigmatism ( r 2 = 0.089, N = 1976). Neglecting the posterior cornea would result in overestimation in WTR anterior corneal eyes and underestimation in ATR and oblique anterior corneal eyes. The posterior surface remained ATR astigmatism in most cases with aging. Furthermore, anterior corneal aberrations measurements overestimated the total corneal aberration in most eyes.Ībout 12.96% of eyes had PCA ≥0.5 D. Compared with total corneal astigmatism, anterior corneal measurements overestimated WTR astigmatism by a mean of 0.24 ± 0.13 (D), and underestimated ATR astigmatism and oblique astigmatism in most eyes. A positive correlation between the magnitude of anterior and posterior corneal astigmatism (r 2 = 0.089, P < 0.001) was found, especially in WTR anterior cornea astigmatism eyes (r 2 = 0.298, P < 0.001). ![]() We found a shift tendency of WTR to ATR with aging in anterior corneal astigmatism, while PCA remains ATR. WTR astigmatism predominated the anterior cornea astigmatism (43.1%), while ATR astigmatism predominated posterior (85.4%) and total corneal astigmatism (47.2%). The mean age of patients was 61.82 ± 13.67 years old. Cataract was diagnosed using slit-lamp examination. The astigmatism and aberrations of anterior and posterior cornea were measured by the rotating Scheimpflug System (Pentacam HR, Oculus). In all, we enrolled 1976 eligible eyes of 1976 cataract patients. To study the prevalence of posterior corneal astigmatism (PCA) and aberration in Chinese eyes before cataract surgery.Ī cross-sectional study was conducted in Eye and ENT Hospital of Fudan University, Shanghai.
0 Comments
Leave a Reply. |