The aim of the study was to determine the age-dependence of the accommodative force on the lens in order to make it clear whether the causes of presbyopia are due to lenticular or extralenticular changes. A finite element model of the lens of an 11-, 29- and 45-year-old human eye was constructed to represent the fully accommodated state. Subsequently, the force that was needed to mould the lens...

I t is a great pleasure to join John Vukich, MD, as a section editor of Advanced Ocular Care’s “Technology Watch” column. I look forward to sharing insights of experts from around the world into the innovations that will pave the way for the future of the eye care industry. Although much has been written on the topic, there is no universally accepted treatment for presbyopia. Therapies range fr...

T he eye’s ability to accommodate is progressively lost with age, which is why this phenomenon is called presbyopia (from the Greek words présbys, meaning old, and ōps, meaning eyes). The condition can be treated with corrective lenses, a method that has been widely used for a long time; however, this approach may not be the most comfortable treatment option for the patient. Today, patients hav...

the ophthalmologic outcomes of diabetes were important. this research is conducted to assess the relation between diabetes and intraocular pressure changes in the patients of avicenna hospital, compared with healthy persons referring to the facility. with cross-sectional research, 400 persons including 200 diabetics and non-diabetics were selected on a random basis over one year in 2012. resear...

Cataract surgery due to advances in small incision surgery evolved from a procedure concerned with the primary focus on the safe removal of cataractous lens to a procedure focused on the best possible postoperative refractive result. As the outcomes of cataract surgery became better, the use of lens surgery as a refractive modality in patients without cataracts has increased in interest and in ...

With the development of photoelectric technology and single-chip microcomputer technology, objective optometry, also known as automatic optometry, is becoming precise. This paper proposed a presbyopia optometry method based on diopter regulation and Charge Couple Device (CCD) imaging technology and, in the meantime, designed a light path that could measure the system. This method projects a tes...

Age related changes in the dynamics of accommodation (far to near focus) and disaccommodation (near to far focus) are reported in this study. Dynamic responses to step stimulus demands from 1D to 6D, in 1D steps, were recorded with a PowerRefractor in 66 subjects in the age range 14-45 years. The accommodative and disaccommodative responses were fit with exponential functions to calculate respo...

Data on geometric and material properties of the human lens derived from various published sources are used to construct axisymmetric, large displacement, finite element models of the accommodating lens of subjects aged 11, 29 and 45 years. The nucleus, cortex, capsule and zonule are modelled as linearly elastic materials. The numerical model of the 45-year lens is found to be significantly les...