We report on the application of a two-dimensional hard x-ray grating interferometer to x-ray optics metrology. The interferometer is sensitive to refraction angles in two perpendicular directions with a precision of 10 nrad. It is used to observe the wavefront changes induced by a single parabolic beryllium focusing lens of large radius of curvature. The lens shape is reconstructed and its resi...

Anterior segment fluorophotometry (topical) and central endothelial cell photography were performed on 40 long-term (2-23 years) contact lens wearers (four groups of ten each: hard, soft, gas permeable, and gas permeable plus prior lens usage) and 40 non-contact lens wearers of similar ages. Morphologically, the endothelial cells of contact lens wearers showed greater variability in size and sh...

Comparisons of lens fiber cell membrane isolation methods were made. Although membrane lipid yield from stirring overnight in hypotonic medium followed by low-speed centrifugation was comparable to that from homogenization and high-speed centrifugation, losses in phosphatidyl ethanolamine were observed with the former method. Lyophilization with vacuum replacement by nitrogen did not exert any ...

The 80-400 f/4.5-5.6G is a relatively large and bulky lens for the genre but overall, given its size I did not find it very heavy and found it to be well balanced even on a light D7100 without optional vertical grip. If this lens had the same metal construction as the 300 f/4 or 70-200 f/2.8 it would be even heavier. There is a lot of polycarbonate in the lens similar to the other recent f/4 ra...

The formula based on keratometric readings which is generally used is unsatisfactory for fitting contact lenses after penetrating keratoplasty, possibly owing to lack of information on the peripheral corneal toricity. In these studies a photokeratoscope was used to examine the entire graft topography. In all cases the corneal configuration became more normal after suture removal, but a consider...

This paper presents design and characterization of a microaccelerometer designated for integration into cataract surgical probe to detect hardness of different eye tissues during cataract surgery. Soft posterior lens capsule of eye can be easily damaged in comparison with hard opaque lens since the surgeon can not see directly behind cutting needle during the surgery. Presence of microsensor he...

Hydrophilic contact lens spoliation can be associated with the deposition of calcium salts. The relationship between the concentration of calcium in tear fluid and contact lens use has been studied in healthy volunteers and in patients using various forms of hard and soft contact lenses, tear samples being collected with Schirmer strips and with lenses in situ. Methods are suggested for correct...

A Kerr-lens mode-locked femtosecond Ti:sapphire laser operating at a repetition rate of 2 GHz is demonstrated. A mirror-dispersion-controlled unidirectional ring cavity delivers nearly bandwidth-limited pulses of 23-fs length. Mode locking is self-starting without a hard aperture in the cavity. The advantages of this high-repetition-rate oscillator in optical time-resolved spectroscopy are demo...

PURPOSE To profile accommodative biometric changes longitudinally and to determine the influence of age-related ocular structural changes on the accommodative response prior to the onset of presbyopia. METHODS Twenty participants (aged 34-41 years) were reviewed at six-monthly intervals over two and a half years. At each visit, ocular biometry was measured with the LenStar biometer (www.Haag-...