Evaluation of Corneal Higher-Order Aberrations by Scheimpflug–Placido Topography in Patients with Different Refractive Errors: A Retrospective Observational Study

Abstract

Purpose. To report the characteristics of anterior and posterior corneal high-order aberrations in patients with different refractive errors. Setting. This study was conducted at Sohag Refractive Center, Sohag, Egypt. Design. This is a retrospective observational study. Methods. This study evaluated 750 patients (750 eyes) who were seeking refractive surgery. The eyes were stratified into five groups (150 eyes/group) based on refractive error: mild-to-moderate myopia, high myopia, hyperopia, simple myopic astigmatism, and simple hypermetropic astigmatism. All patients were subjected to comprehensive ophthalmological examination including corneal topography and corneal aberrometry using the Scheimpflug–Placido topography (Sirius, CSO, Italy). Results. Coma aberration was statistically significant when compared in all five groups (P=0.01). It was highest in the hypermetropia group (0.26 ± 0.12 μm) but lower in the moderate myopia, high myopia, myopic astigmatism, and hypermetropic astigmatism groups. Spherical aberration was lowest in the hypermetropia group and significantly different from that in the other groups. Trefoil was statistically insignificant when all groups were compared (P=0.062) but was highest in the myopic astigmatism group (0.24 ± 0.25 μm). Total RMS peaked in the hypermetropia group (0.99 ± 0.70). Conclusions. In normal corneas and regular refractive errors, the cornea-induced high-order aberration was minimal, and all types of refractive errors were associated with certain types of high-order aberrations, with a significant increase in spherical aberration in the hypermetropia group.

Comparison of Clinical Performance and Subjective Outcomes Between Two Diffractive Trifocal Intraocular Lenses (IOLs) and One Monofocal IOL in Bilateral Cataract Surgery

“…The RayOne group showed lower values for overall total ocular aberrations and for internal HOA compared to the PanOptix group, whilst this was not statistically signi cant. The corneal aberrations were similar in the three groups, and were not related to the multifocal IOL design, as corneal aberrations are known to exist in normal corneas as a result of individual anatomy or refractive error [22]. Internal aberrations are considered mainly to be related to the IOL, and are known to a cause of visual disturbances due to dispersion of light inside the eye [21].…”

<p>Inter-Ocular Asymmetry in Anterior Corneal Aberrations Using Placido Disk-Based Topography</p>

“…The study was aimed at assessing the inter-ocular asymmetry in anterior corneal aberrations using instruments that are readily and commonly available in most optometric practices or stand-alone ophthalmology clinics which has led to some limitations in the study. First, as also noted by previous authors, 17 the inability to have precisely equal pupil size in the explored eyes affects reliable comparison and requires caution. Second, the Placido-based topographers are limited to providing analysis of data obtained from the anterior cornea; thus, the lack of information about the posterior corneal surface indicates that further research would be beneficial to study the concept of inter-ocular asymmetry in posterior corneal aberrations using an aberrometer, which is not commonly available in an optometric setting or many stand-alone ophthalmology clinics.…”

Accommodative amplitudes and high-order aberrations in patients with multiple sclerosis with optic nerve ınvolvement

“…The visual impulse travels to the retinal ganglion cells and then to the visual cortex by the optic nerve, optic chiasma, optic tract, and optic radiation. In the midbrain, the afferent fibers synapse with the oculomotor nucleus and the Edinger-Westphal (EW) nucleus (9)(10)(11)(12)(13)(14)(15)(16) . The oculomotor nerve carries the motor fibers to both medial rectus muscles to converge.…”

“…Higher-order aberrations (HOAs) are complex and subtle refractive errors occurring in any part of the optical axis, having an impact on visual and retinal image quality of an eye. The HOAs depend on age, refractive error (myopia, hypermetropia, or astigmatism), and pupil size, as well as tear film instability and corneal irregularities (14) . Accommodation may alter the HOAs in healthy individuals (15) .…”