The light transmission of freshly excised normal human lenses has been measured atfive visible wavelengths. The lens profile has also been recorded and used to calculate light lossper unit pathlength of lens. This loss, although made up of absorption and scatter thecontributions of which cannot be quantified, may be regarded as due to a hypothetical absorbingpigment. The loss is...

Lens average and equivalent refractive indices are required for purposes such as lens thickness estimation and optical modeling. We modeled the refractive index gradient as a power function of the normalized distance from lens center. Average index along the lens axis was estimated by integration. Equivalent index was estimated by raytracing through a model eye to establish ocular refraction, a...

BACKGROUND/AIM To investigate the biometric components and refractive errors in premature infants with or without retinopathy of prematurity (ROP). MATERIALS AND METHODS Anterior chamber depth, lens thickness, vitreous length, and axial length were measured with an ultrasound biometer. Cycloplegic refraction was performed by streak skiascopy. Infants with or without ROP were grouped according...

Dear Editor Mordi and Ciuffreda (2004) have used an objective infrared optometer to measure the dynamic aspects of accommodation with aging in a large well-designed study. Their study demonstrates no change in the time constant and peak velocity/amplitude of accommodation with age. Based upon this observation, the authors correctly conclude that their findings imply that presbyopia cannot be du...

PURPOSE To compare the efficacy of 2.5% sodium hyaluronate (BD Multivisc) with the soft shell technique in reducing corneal endothelial cell damage during cataract phacoemulsification in patients with hard lens nucleus (3+) and cornea guttata. METHODS Thirty patients (37 eyes) scheduled for cataract surgery at Department of Ophthalmology and Visual Sciences, University Hospital San Raffaele, ...

PURPOSE To characterize short-term changes induced by pars plana vitrectomy on anterior segment depth and lens thickness by means of high-frequency ultrasound biomicroscopy. METHODS We undertook a prospective case series study on consecutive patients referred for pars plana vitrectomy as the sole procedure in our institution between 2005 and 2007. Twenty-eight eyes of 28 patients undergoing p...

Ground water resources of atolls, already minimal due to the small surface area and low elevation of the islands, are also subject to recurring, and sometimes devastating, droughts. As ground water resources become the sole fresh water source when rain catchment supplies are exhausted, it is critical to assess current groundwater resources and predict their depletion during drought conditions. ...

PURPOSE To investigate the association between ocular biometrics such as axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and corneal power (CP) with different refractive errors. METHODS In a cross-sectional study on the 40 to 64-year-old population of Shahroud, random cluster sampling was performed. Ocular biometrics were measured using the A...

Corneal changes were monitored in 14 subjects following 3 hr of eye closure while wearing selected oxygen permeable rigid and hydrogel lenses. The mean increase in corneal thickness ranged from 82.5 to 29.5 microns for rigid lenses with oxygen transmissibilities (Dk/L) between 0.2 X 10(-9) and 57.0 X 10(-9) (cm/sec) (ml O2/ml X mmHg), respectively, and ranged from 82.5 to 23.5 microns for hydro...

introduction: the aim of this study is to investigate the effect of one nitric oxide inhibitor on the thickness and number of circular smooth muscle cells of pylor in rat embryo. material and methods: to determine the influence of nitric oxide reduction on the muscular layer of pylor in rat embryo, in the present study, pregnant sprague-dawley rats received the no synthase inhibitor n-nitro-l-a...