Effects of lacrimal drainage occlusion with nondissolvable intracanalicular plugs on hydrogel contact lens wear.

Purpose: To investigate effects of lacrimal drainage occlusion with intracanalicular silicone plugs in hydrogel lens wearers with the symptom of dryness. Effects of rewetting drops in combination with the plugs were also evaluated.

Methods: A 6-week, prospective, double masked, placebo-controlled study design was followed.

Swelling of collagen intracanalicular implants.

Background: Absorbable intracanalicular collagen implants are used to attempt to determine if permanent closure of the tear drainage system will diminish or alleviate the signs and symptoms of dryness. The rate of swelling of the collagen implants was measured in vitro in this study.

Methods: Collagen implants were submersed in saline, Refresh Plus artificial tears or Tobrex antibiotic solution on a hanging drop microscope slide.

A synopsis of extended-wear lenses and lens care regimens.

The clinical properties of hydrogel and rigid gas-permeable contact lenses for extended wear are examined, with emphasis on oxygen permeability and transmissibility, so that clinicians may select lenses likely to minimize corneal edema or may predict the amount of edema likely with a given lens. Lens deposit formation and related problems are also described, as are lens care systems, particularly their limitations with respect to preventing infections. The advantages, disadvantages, and limitations of lens cleaners are discussed, and recommendations for use are provided.

One-week vs. 2-week hydrogel extended wear schedules.

Fifteen myopic patients wore 58% water content lenses for extended wear. The lens on one eye was removed weekly for 1 night and the lens on the other eye was removed only every 2 weeks. The patients were followed for 3 months.

Effect of some solutions on HGP contact lens parameters.

The effect of five common contact lens solutions on the overall diameter and base curve radii of PMMA, siloxane/acrylate and fluorosiloxane/acrylate lenses was studied. The alcohol containing cleaner, Miraflow, caused a significant swelling and base curve change of the siloxane/acrylate and fluorosiloxane/acrylate lenses with 30 minutes or longer soaking. Miraflow did not affect PMMA lenses.

Measured power distribution across the Bausch and Lomb Soflens (PAI) Bifocal.

The power distribution across Bausch and Lomb Soflens PAI Bifocal lenses was measured using a series of double aperture stops on a lensometer. The add power at different distances from the lens center is presented. A gradual increase in plus power approximately equivalent to an aspheric back surface of an eccentricity of 0.

Critical base curve and diameter interval in the fitting of spherical soft contact lenses.

The effect of base curve and diameter variation on the fit or DuraSoft lenses was evaluated in terms of eight clinical fitting criteria: refraction, lens position, centering ability, stability of vision, amount and direction of movement, subjective comfort, and corneal physiological response. The minimum or critical intervals of base curve and diameter change necessary to produce significant changes in these criteria were determined. The results are discussed in relation to the design of diagnostic sets of lenses and the changes necessary to produce effective variations in clinical fit.

A comparison of different rigid contact lenses: edge thicknesses and contours.

The edge thickness and contour of rigid lenses is an important factor in lens comfort and acceptance. In this study the edges of two CAB lenses, a PMMA-silicone combination lens, a pure silicone lens had standard PMMA lenses are evaluated by molding the lenses. Considerable variation in thickness and contour of the peripheral portion of the lenses were found.

Clinical study of corneal response to the wear of low water content soft lenses.

The changes in central and peripheral corneal thickness and topography during initial (1st-day) wear, adaptation to, and long-term wear of the DuraSoft lens were monitored in a group of 10 patients. Monitoring was by means of the electronic digital pachometer and the photoelectronic keratoscope (PEK). A variety of physiological responses to lens wear was noted in individual patients, but generally the changes occurring were comparable to those reported for other soft lenses.

Inspection of back surface aspheric contact lenses.

Two methods of clinically inspecting and verifying rigid back surface aspheric contact lenses were investigated. A modification of the Radiuscope was found to be an accurate method for making such measurements. Measurement data of a number of aspheric lenses obtained by using this procedure are presented.

The United States Food and Drug Administration and the practice of optometry.

In the past decade the United States Food and Drug Administration has become increasingly involved with the regulation of materials used in the practice of optometry. It is the purpose of this paper to help the practitioner understand the FDA involvement, historically and legally, organization, how one can have input into the process, the procedures for testing and approving new drugs and devices, their regulation and the advantages and disadvantages of such control.

Soft lens cleaners: their effectiveness in removing depostis.

The useful life of a hydrophilic lens is often reduced by deposits forming on or within the polymeric structure of the lens. To eliminate this problem, several cleaning agents have been formulated to prevent and/or remove these deposits. The efficacy of these agents in cleaning heavily deposited lenses is the topic of this investigation.

Measured and laboratory-stated parameters of hydrophilic contact lenses.

One hundred thirty-one new hydrophilic lenses made by 3 manufacturers were randomly selected from an optometry clinic for measurement and inspection. Approximately 60% of the base-curve specifications fell within the following ranges for the measured dimensions: Bausch & Lomb Soflens contact lenses, less than 0.150 mm; Milton Roy Naturvue lenses, less than 0.

The "aging" of a HEMA contact lens.

The physical characteristics and attendant patient complaints associated with termination of the useful service lives of 26 HEMA lenses are compared with the characteristics of a control (undispensed) population of such lenses.

Effectiveness of an enzyme in removing deposits from hydrophilic lenses.

Bausch and Lomb Soflens contact lenses with various types of deposits were cleaned with the Allergan Enzymatic Contact Lens Cleaner. Its effectiveness in removing the deposits varied with the type of deposit. Effectiveness of the cleaner can be predicted from the initial appearance of the deposit.

Inspecting the integrity of hydrophilic lenses.

Inspection of the surface quality of hydrophilic lenses is important. Methods of inspection and illustrations of common defects are illustrated.