Optical quality of intraocular lenses after several years in the human eye

2013

The optical quality of explanted intraocular lenses (IOLs) was analysed to verify if their quality is maintained after having been in the human eye for several years. Twenty-five explanted IOLs were studied, 10 because of intraocular luxation and 15 from corneal donors. The dioptric power and modulation transfer function (MTF) were determined to discover the image quality of the IOLs. The spectral transmission was also established to ascertain whether the filter against ultraviolet (UV) radiation was still effective. The results show that the MTF of implanted IOLs is maintained and therefore so is the image quality they provide. Only decay in the MTF of some of the explanted IOLs was observ…

ATD perimetry in glaucoma and ocular hypertensive patients. A preliminar study

2007

Purpose: The new ATD perimetry assesses contrast sentivity thresholds for the three afferent sensory pathways of the visual system. Our aim is to compare contrast sensitivity to stimuli with different spatio-temporal frequencies in glaucomatous (G) and ocular hypertensive (OHT) subjects. Methods: Twenty three G and OHT subjects were selected from the ophthalmic clinic, all subjects signed an informed consent. Inclusion criteria were diagnosis of G or OHT, normal Farnsworth-Munsell color test, ametropia less than 6 D, visual acuity over 20/30, absence of previous ocular surgery and experience in perimetry. Twenty locations and the fovea were evaluated in a 60o x 40o fovea-centered field. Eig…

Asymmetric colour matching: memory matching versus simultaneous matching

2001

We have compared corresponding pairs obtained by simultaneous matching (haploscopic matching) and by memory matching (after 10 min) using 34 reference tests selected from the Munsell Atlas (glossy), belonging to the four main hues 5Y, 5G, 5PB, and 5RP. These colours lie very close to the F1 and F2 axes in the SVF space, where we have analyzed our results. Illuminants D65 and A were used as reference and matching illuminants, respectively. Our results show for both kinds of matching a tendency to select more colourful colours than the original ones, with significant differences between matching and test colours, whereas hue does not seem to follow a definite pattern. This behavior is similar…

Brightness induction in a chromatic center?achromatic surround configuration

1997