Optical quality of the eye in subjects with normal and excellent visual acuity.
نویسندگان
چکیده
PURPOSE To study the relationship between visual acuity (VA) and the eye's optical quality in subjects with normal and excellent spatial vision. VA ranged from decimal values of 1.0 (20/20) to 2.0 (20/10) when defocus and astigmatism were carefully corrected. METHODS In 60 eyes of young subjects, visual and optical performance with the natural pupil were measured. A forced-choice procedure was used to measure tumbling-E high-contrast VA (HCVA) and low-contrast VA (LCVA). Wavefront aberration (WA) was measured using a Hartmann-Shack sensor. The associated point-spread function (PSF) and modulation transfer function (MTF) were also estimated. High-order aberrations (HOA) and several image quality parameters were represented as a function of VA. Subjects were classified into three groups according to their VA, and average optical parameters were calculated. RESULTS Coma and trefoil vary between 0 and 0.5 mum, and spherical aberration ranges from -0.40 mum to +0.45 mum, with an average value of approximately zero. LCVA is not correlated with any of the aberration terms. Coma and spherical aberration are not correlated with HCVA. However, eyes with trefoil equal to or higher than 0.25 mum have an HCVA less than 1.5. The average optical quality in eyes with HCVA greater than 1.4 is slightly better than in eyes with normal VA. However, some eyes had relatively poor image quality and excellent VA. CONCLUSIONS No significant correlations were found between VA measurements and the optical quality of the eye in young subjects with normal or excellent spatial vision. Some subjects with normal degrees of aberrations attained excellent VA.
منابع مشابه
حدت بینایی و عوامل مؤثر بر آن در زنان قالیباف: روستای فردو شهرستان قم
Background: Healthy vision of workers is one of the important elements in carpet weaving industry which has essential role in improving of the job quality and efficiency. Visual acuity is the primary outcome measure in most studies involving eye diseases. Ihe aim of this study was determination of visual acuity and its effective factors in women carpet weaver in fordu rural area of Qom has ...
متن کاملبررسی مقایسهای حدت بینایی و حساسیت به کنتراست در رانندگان مراجعهکننده به درمانگاه چشم بیمارستان فرشچیان همدان
Background and Objective: Car accidents are the second leading cause of mortality in Iran. For safe driving, drivers require minimum acceptable visual acuity. In Iran, the accepted routine test to take driving license is Snellen vision chart, which is not adequate for visual acuity determination in real and natural environment. It seems that introducing a more sensitive and specific screening t...
متن کاملکاربرد لنزهای داخل چشمی در جراحی کاتاراکت و عوامل تأثیرگذار بر دید بیمار
Introduction: With the growing and rapid development of refractive surgery, researches focus increasingly on improvement of visual quality after cataract surgery. Intraocular lenses (IOLs) were a successful effort in the field of cataract surgery. Despite significant advances in cataract surgery, several complications related to surgical technique and IOL design after surgery can cause vision c...
متن کاملA Quantitative Investigation on the Effect of Edge Enhancement for Improving Visual Acuity at Different Levels of Contrast
Background: The major limitation in human vision is refractive error. Auxiliary equipment and methods for these people are not always available. In addition, limited range of accommodation in adult people when switching from a far point to a near point is not simply possible. In this paper, we are looking for solutions to use the facilities of digital image processing and displaying to improve ...
متن کاملPurtscher’s Retinopathy in a Patient with Falling Down: A Case Report
Purpose: To report a case of Purtscher’s Retinopathy in a patient with falling down. Case Report: A 25-year-old man with no history of specific disease referred to the ophthalmology clinic of Imam Hossein Hospital 2 days after falling due to a sudden vision loss in his right eye. Best-corrected visual acuity was counting finger 1m in the right and 10/10 in the left eye and Marcus Gunn pupil was...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Investigative ophthalmology & visual science
دوره 49 10 شماره
صفحات -
تاریخ انتشار 2008