Ocular aberrations and wavefront aberrometry: A review

Abstract

Wavefront aberrations can be described as deviations of the wavefront exiting the eye froma reference wavefront that is aberration free and diffraction limited. Ocular aberrations canbe sub-categorised as lower and higher order aberrations. Ocular aberrations have promptedinterest amongst the ocular healthcare community owing to their influences on the visualfunctioning of patients as well as differences observed in ocular aberrations through the useof refractive surgery both pre- and post-operatively. Uncompensated refractive error remainsone of the most common reasons for which patients consult optometrists. Compensationof refractive error, or lower order aberrations, has become a routine procedure during anoptometric examination. However, there are some patients who experience visual symptomseven after their refractive errors have been compensated via spectacles or contact lenses.Higher-order aberrations may be the source of these visual disturbances. Refractive surgeryhas been found to influence and even induce various changes in higher-order aberrationspost-operatively, which in turn has led to increased interest in wavefront aberrations and howthe measurement of these aberrations can improve diagnosis and treatment within optometryand ophthalmology.

The Accuracy of Zernike Reconstruction of Ocular Aberrations With Measurement Noise

“…Consequently, the representation of OAs plays a crucial role in the field of vision correction [1]. There are different mathematical representations to describe OAs [16]. However, due to the orthogonality and aberration balancing properties, Zernike representation is widely used to express OAs [2, 7, 8, 9, 10].…”

Prevalence and determinants of refractive errors at Sekororo District Hospital in Limpopo Province, South Africa

“…Refractive errors are related to second lower-order aberrations that occur because of an imperfect optical system not focusing retinal images of light from an object in the external world, thereby leading to blurred images in the absence of any optical or surgical compensation. 5 Refractive errors of the eye include spherical refractive errors (myopia and hyperopia sometimes called hypermetropia) and nonspherical refractive errors (astigmatism). Ametropia is a medical term that refers to the state of the eye in which refractive error is present.…”

“…Ametropia is a medical term that refers to the state of the eye in which refractive error is present. 1,2,3,4,5,6 Common causative factors for URE include longer or shorter axial lengths rather than the average axial length of the eyeball, which is approximately 24.4 mm. 1,2,4,6 An increased axial length (>24.4 mm) is often associated with an increased risk of myopia, while decreased axial length is associated with an increased risk of hyperopia.…”

Low and high order aberrations in the eyes of patients with levothyroxine treated hypothyroidism — comparison and analysis

“…The coefficients are calculated using differences between the wavefront and the reference surface. Both RMS and Zernike polynomials are measured in micrometers [7]. When the light passes through ocular media, it is affected by imperfections of the eye optical system.…”