Written informed consent was obtained from all participants.Īdult subjects were recruited from March 2018 to July 2018. This cross-sectional study followed the tenets of the Declaration of Helsinki and was approved by the Institutional Review Board of Taipei Veterans General Hospital, Taipei, Taiwan (VGH IRB number: 201803002BC). As a result, factors including sex, refractive errors, baseline pupil size and its change during accommodation were also investigated. Besides, since TONOREF III can measure the pupil size and refractive change during accommodation at the same time, it is interesting to explore the association between pupil size and AA. It is worthwhile to evaluate these factors. Because previous studies argued that sex and refractive errors were factors affecting AA and the results remained controversial. Since age is a known factor affecting the accommodation, we investigated the associations between the measured AA and age to verify clinical feasibility of the TONOREF III. The present study aimed to evaluate the repeatability of objective measurements of AA using the TONOREF III. To the best of our knowledge, no previous study has reported the repeatability of AA measurements using the TONOREF III. In brief, objective measurements of accommodation are obtained dynamically by measuring the dioptric change of the subject while the examinee is focusing on a virtual object which moves from distance to near. The mechanism of measuring refraction and accommodation is identical to the NIDEK Auto Ref / Keratometer (ARK-1s / 1a). Different from the Shin-Nippon SRW-5000 or Grand-Seiko WR-5100K open-field autorefractors using an external target, it dynamically and simultaneously measures the AA as well as the changes in pupil size in 30 seconds using an internally virtual object. It has the advantage of taking up less space and time-saving for measuring the refraction, intraocular pressure, central corneal thickness and AA using the same machine. The NIDEK TONOREF III (NIDEK Co., Ltd., Japan) has a built-in auto refractometer, auto keratometer, non-contact tonometer, and non-contact pachymeter. In addition, the use of electronic devices may be associated with decreased accommodation and its association with aesthenopic symptoms is worth further investigation with objective measurement. For new therapy proclaiming that it can restore accommodation for patients with early presbyopia, it is also helpful to validate the effect using objective measurements. Because diabetes mellitus, Down syndrome or drugs such as topiramate may lead to early decreased accommodation, timely diagnosis and intervention of these underlying causes may be helpful to patients. It is worthwhile to identify if they had decreased accommodation in their ages and the actual diopter of the AA using objective measurements. In daily clinical practice, sometimes there are young adults and middle-aged patients complaining about eye strain or blurred vision when seeing near objects. The AA measured subjectively is at best near vision capacity rather than the actual refractive changes of the eye, whereas objective measurements could represent actual changes in the optic power of the eye. Several studies measuring the AA objectively using an open-field autorefractor have demonstrated a lag in accommodation that is the amount by which the accommodative response is less than the dioptric stimulus to accommodation. The change in refraction of the eye measured by an autorefractor while the subject accommodates from a distant to near target represents an objective measurement of accommodation. The amplitude of accommodation (AA) is the maximal potential increase in optical power that an eye can achieve in adjusting its focus. Accommodation is adjustment in the refractive power of the crystalline lens so that the images of objects can be brought into focus on the retina over a range of distances.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |