Changes in Irregular Corneal Astigmatism With Age in Eyes With and Without Cataract Surgery

Abstract

In patients from 50 to 80 years of age who underwent cataract surgery, irregular corneal astigmatism, both the asymmetry and higher-order irregularity components, increased significantly with increasing age, whereas regular astigmatism induces an against-the-rule shift. The higher-order irregularity component persistently increased postoperatively, whereas the asymmetry component did not change significantly.

Incision Site in Manual Small Incision Cataract Surgery in Case of Preoperative Direct Astigmatism

“…The average age of our patients was 30.66 years, it is a very young age, within the framework of a study on the cataract surgery, or generally the average age revolves around 60 years. This is due to the fact that astigmatism reverses with age [6]. There is more direct astigmatism in young subjects, and reverse in older subjects.…”

“…In order to reduce occurrence of SIA, the authors propose to make temporal incisions by MSICS [3] [4] [5]. Temporal incisions generate less SIA because of the distance of this site from the visual axis, and the eyelid blink tends to create a drag on the incision [4], but also because of the predominance of reverse (irregular) astigmatisms in the elderly [6] most affected by cataracts. In these patients with reverse astigmatism, SIA is opposed to preexisting astigmatism with a tendency to reduce the latter [7].…”

Comparison of Two Novel Swept-Source Optical Coherence Tomography Devices to A Partial Coherence Interferometry-Based Biometer

“…Our data suggested that ANTERION demonstrated superior repeatability for the measurement of J0, which represents with-the-rule and against-the-rule astigmatism, and its agreement with the IOLMaster500 was poor. In practice, it is important to perform corneal topography when before implanting a toric IOL in cataract surgery since irregular corneal astigmatism, which is not correctable by toric IOL, has been shown to increase with increasing age 28 . It is likely that the difference between PCI-based and swept-source OCT based devices exists because of the different methods used to analyze the mires of spots re ected from the cornea.…”

Non-Orthogonal Corneal Astigmatism among Normal and Keratoconic Brazilian and Chinese populations

“…The assumption of orthogonality between steep and flat meridians in corneal power maps has been a common feature in the analysis of astigmatism and in clinical techniques to determine the eye's visual acuity, although possible meridional non-orthogonality has been identified earlier. 11,14,[32][33][34] Optical power nonorthogonality was acknowledged in the literature as a contributing factor to high-order aberrations and identified by indices that do not provide clinical parameters like refractive power or axis angle. Despite being expressed quantitatively and statistically by a normalized Fourier series coefficient called the irregularity index, no expression of non-orthogonal astigmatism magnitude or axis angle has been presented.…”

“…In fact, the existing literature that evaluates corneal irregularity by Fourier series harmonic ignores the irregular astigmatism phase angle β 3 and does not associate it with a specific physical meaning. 11,14,15 While it is acknowledged that a quantitative degree of irregularity in refractive power exists in normal eyes and this knowledge has been simulated by mathematical modeling 16 , no technique is available to locate the axes of irregular astigmatism. As a result, irregular astigmatism cannot be fully corrected by existing spectacle lenses and a degree of astigmatism will remain after correction.…”