A wavefront aberrometer for dynamic high-order aberration measurement

In the human eye, accommodation is essential for functional vision. However, the mechanisms regulating accommodation and the ocular parameters affecting aberrations remain to be explored. In order to measure the alterations of ocular aberration and crystalline lens biometry during dynamic accommodative stimuli, we designed an optical coherence tomography with ultra-long penetration depth (UL-OCT) combined with a Shack–Hartmann wavefront sensor (SHWFS). This integrated set up measures human eye's anterior segment as well as monochromatic high-order aberrations (HOAs) with 6 μm resolution and (1/20) λ accuracy. A total of 10 healthy volunteers without ocular diseases were examined. Upon exposure to accommodative stimuli, the wavefront aberrations became larger. Among the anterior segment biometry, the anterior crystalline lens demonstrated significant curvature during accommodation and was the major cause of high-order aberration. These findings suggest that the front surface of the crystalline lens can significantly affect variation among aberrations, which is a key factor underlying the quality of human vision.

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Contralateral Eye Study On The Characteristics of Corneal Aberration In Patients With Bilateral Keratoconus And Unilateral Corneal Vogt’s Striae

10.21203/rs.3.rs-1133942/v1 ◽

2021 ◽

Author(s):

Jing Li ◽

Yaohua Zhang ◽

Yong Li ◽

Yan Cai ◽

Jing Du ◽

...

Keyword(s):

Spherical Aberration ◽

Front Surface ◽

High Order ◽

Back Surface ◽

Morphological Parameters ◽

High Order Aberration ◽

Contralateral Eye

Abstract Purpose: To assess the corneal high-order aberration(HOA) and its correlation with corneal morphological parameters in patients with bilateral keratoconus (KCN) and unilateral Vogt’s striae.Methods: A total of 168 eyes of 84 patients with KCN, whose corneas had definite signs of unilateral Vogt’s striae were enrolled. Corneal HOA and morphological parameters were measured using Pentacam HR.Results: The corneal morphological parameters between KCN eyes with and without Vogt’s striae were evidently different (P < 0.001). The 3rd coma 90°, 4th spherical aberration, 5th coma 90°, RMS (total), and RMS (HOA) in the front, back surfaces and total cornea in KCN eyes with Vogt’s striae were significantly higher than those in KCN eyes without Vogt’s striae (P < 0.001). In KCN eyes with Vogt’s striae, the 3rd coma 90° and 4th spherical aberration in the front surface and total cornea were negatively correlated with K1, K2, Km, Kmax, ACE, and PCE (P < 0.05). The 3rd coma 90° , 4th spherical aberration in back surface and RMS (total), RMS (HOA) in the front, back surfaces, total cornea were positively correlated with K1, K2, Km, Kmax, ACE, and PCE (P < 0.05).Conclusions: Corneal HOA especially vertical coma and spherical aberration may increase when Vogt’s striae appeared in KCN eyes. The scale of increase was significantly related with changes in corneal shapes.

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High Order Aberration Outcomes of Corneal Collagen Crosslinking in Eyes with Keratoconus and Post-LASIK Ectasia

International Journal of Keratoconus and Ectatic Corneal Diseases ◽

10.5005/jp-journals-10025-1088 ◽

2014 ◽

Vol 3 (3) ◽

pp. 107-112

Author(s):

Adam Muzychuk ◽

Victor Penner ◽

Guillermo Rocha

Keyword(s):

Visual Acuity ◽

Spherical Aberration ◽

Retrospective Chart Review ◽

High Order ◽

Collagen Crosslinking ◽

Distance Visual Acuity ◽

High Order Aberration ◽

Manifest Refraction ◽

Corneal Collagen Crosslinking ◽

Corneal Collagen

ABSTRACT Purpose To evaluate the effect of riboflavin and ultraviolet- A-induced corneal collagen crosslinking (CXL) on high order aberrations (HOA) up to third-order at 6 months using the iTrace wavefront aberrometer in patients with progressive keratoconus and post-LASIK ectasia. Materials and methods Ongoing retrospective chart review of patients having undergone CXL. The iTrace (Tracey Technologies, Houston, TX) was used to evaluate HOA. Patient data was collected from a single clinical site pre- and 6 months postoperatively. Data collected included logMAR uncorrected distance visual acuity (UDVA), logMAR corrected distance visual acuity (CDVA), manifest refraction, and HOA measurements. Data was analyzed with paired two-tailed student's t-test. Results 18 eyes (9M:4F, mean age 29.2 years, range 16-45) had 6 months of follow-up. Total HOAs, total coma and total trefoil were significantly reduced at 6 months by 16, 33 and 26% respectively (p < 0.05). Nonsignificant trends toward improvement were seen in spherical aberration, secondary astigmatism and UDVA. There were no statistically significant changes in manifest refraction or CDVA. Conclusion Improvement in high order aberration profile is one mechanism by which corneal collagen crosslinking enhances visual function in ectatic corneas. Total HOA and total coma measures are the most commonly reported improvements in HOA measures in previous studies, while total trefoil has only been observed in one other study. The improvements seen in HOAs remain fairly modest which likely accounts for the lack of measureable improvement in high-contrast visual acuity measures, such as Snellen UDVA and CDVA. This study is the first to report HOA outcomes with the iTrace wavefront aberrometer. How to cite this article Muzychuk A, Penner V, Rocha G. High Order Aberration Outcomes of Corneal Collagen Crosslinking in Eyes with Keratoconus and Post-LASIK Ectasia. Int J Kerat Ect Cor Dis 2014;3(3):107-112.

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Analysis of corneal real astigmatism and high order aberration changes that cause visual disturbances after lower eyelid epiblepharon repair surgery

Scientific Reports ◽

10.1038/s41598-020-64386-6 ◽

2020 ◽

Vol 10 (1) ◽

Cited By ~ 1

Author(s):

Dong Cheol Lee

Keyword(s):

Lower Eyelid ◽

High Order ◽

High Order Aberration ◽

Visual Disturbances

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