Refractive errors that are more subtle and complex as compared to near-and-farsightedness and astigmatism are known as Higher-Order Aberrations (HOAs). Due to the nature of the onset, these aren’t corrected through normal eyeglasses and contact lenses. HOAs are detected through certain eye exams conducted using wavefront technology.
Higher-Order Aberrations also have many different unfamiliar names such as spherical aberration, trefoil and coma. These aberrations hamper the ability to see clearly at night causing certain halos, glares, blurring, starburst and diplopia which is dual-vision. A medical research surprisingly revealed that no eye is 100% perfect which means each has a certain degree of Higher-Order Aberrations.
Positive diagnosis isn’t something to be worried about unless it cause significant damage to the vision. Regular visit to an eye hospital in Abu Dhabi or at your most recent location per se would help with timely treatment of all such vision anomalies.
A detailed overview
Higher-Order Aberration is distortion acquired by wavefront light when it passes through the eye following certain irregularities over the refractive components namely cornea, crystalline lens, tear film, aqueous and vitreous humour.
Abnormal or irregular bending/curvature of the crystalline lens and cornea further contribute to distortion through wavefront light. More serious onset occurs due to corneal scarring from trauma, a disease or even eye surgery.
Cataracts which is clouding of the natural lens causes Higher-Order Aberrations as well as diminishing of the ocular tear film due to dry eye syndrome! Vision is hampered due to irregular light pattern falling on the retina.
Diagnosis
Diagnosis or identification of HOAs is done by wavefront exam which determines the type of distortion from the light when is passes through the eye. Since no eye is optically 100% perfect, uniform wavefront light rays when penetrates through the eye takes on a three-dimensional and distorted shapes. By now, more or less 60 distinct wavefront shapes or deviations have been identified. Refractive errors of the eye are described by two categories of the aberrations namely;
- Lower-Order
It consists of certain defocusing due to near and farsightedness alongside astigmatism taking on approximately 85% of all the eye deviations.
- Higher-Order
A variety of aberrations fall in the category with some identified as coma, trefoil and spherical whereas others take on mathematical expressions such as Zernike polynomials. Around 15% of the total eye aberrations fall under HOAs.
Impact on vision quality
Impact of HOAs on the vision quality depends on various factors that also include underlying cause of the aberration. Individuals having larger than average pupils may come across more significant vision anomalies due to HOAsespecially in dimly lit environment when pupil naturally expand for a clearer view and to get accustomed to the dark.
That said, even those with small or average sized pupils complain of vision problems where HOAs triggers certain conditions like corneal scarring or development of cataracts. More serious impact and non-treatment may even lead to blindness or long-term vision loss.
Conclusion
All eye and vision-related anomalies must be reported at an eye hospital for accurate diagnosis and timely treatment before the condition worsens.
