Monthly Archives: 09:15 AM

Focus correction in an apodized system with spherical aberration

CiViUM scientists have found that if the eye does not suffer the so-called Stiles-Crawford effect we would need more correction to observe nearby objects, due to the interaction with certain eye defects (aberrations). This effect produces that the light entering into the eye near the edge of the pupil is attenuated when reaching the retina.


This behavior is called apodization and in artificial systems, such as telescopes, is used to facilitate the detection of planets near bright stars.
In general, when observing distant objects the eye has positive spherical aberration. However, when the observed objects approach the eye, the change in the shape of the lens produces this aberration to decrease, usually becoming negative. The combination of the apodization with this change in sign produces that we have the best vision with lower correction than in the case the eye does not behave as described by the Stiles-Crawford effect. In this study the mathematical calculations needed to calculate the effect on any optical system affected of spherical aberration and apodization have been developed.

Amount of aspheric intraocular lens decentration that maintains the intraocular lens’ optical advantages

A recent publication from researchers of CiViUM group in the “Journal of Cataract and Refractive Surgery” gives explanation to undesirable effects suffered by some patients of cataract surgery, replacing its crystalline lens with and aspheric intraocular lens. This type of lens is specially designed with the aim to enhance images in the patient’s retina.

paula decentration big

However, clinical studies show that some patients experience a worsening of their vision regarding the expected results. In the published paper it is shown through mathematical calculations that improper centering of the intraocular lens during operation causes a loss of quality in the patient’s vision. This study allows to know a priori for each aspheric lens design, the amount of decentration (tenths of a millimeter) that can be tolerated in the intervention in order to the special design of these lenses do not end up eroding the quality of the patient’s vision for what they were devised.

In Águilas the XII Course of the Current Issues in Vision Science is concluded

During the 4, 5 and 6th of September in Aguilas we celebrated the XII edition of the summer course “Current Issues in Vision Science: The International Year of Light”, directed by professors Vicente Fernández and Norberto López fron the University of Murcia. The course has reunited numerous researchers and professors from the field of vision sciences, including doctor José Manuel González Méijome, from the University of Minho (Braga, Portugal) with his talk about the progression of myopia. María Sagrario Millán García Varela from the Technical University of Cataluña gave a talk about the most recent intraocular lenses.
The members of the CIVIUM research group also gave interesting lectures. Diego López Alcón talked about various subjective and objective methods of addition, Vicente Fernández, a great professional in his field, talked about visual rehabilitation of children, and Francisco Lara spoke about the impact of luminosity on close vision. The students also participated in a workshop on refraction.
The next edition of the course awaits us the following year and all the information can be found on the official website (in Spanish) of the Universidad del Mar.

civium (from latin, genitive plural of civis-civis, "belong to the citizens")