Menicon Z 30-day continuous wear lenses: a clinical comparison to Acuvue 7-day extended wear lenses

Contact Lens Fitting Profile in Portugal in 2005: Strategies for First Fits and Refits

PURPOSE

To evaluate the standards of contact lens practice in Portugal, with particular attention paid to the characteristics of first fits and refits regarding aspects such as symptoms of dryness, overnight wear, silicone hydrogel and multifocal prescriptions, and care systems.

METHODS

A questionnaire was distributed to 300 contact lens practitioners in Portugal, and they were asked to complete them with the following first 10 fittings (only right eye of each patient). Fifty-six questionnaires were returned to total 529 fittings.

RESULTS

The mean age of contact lens wearers was 28.1 +/- 10.1 years, and 94.4% of the wearers were fitted with soft contact lenses (67.9% hydrogel lenses, 21.2% silicone hydrogel lenses, and 5.2% biomimetic soft contact lenses). Sixty percent of patients wore their contact lenses for 9 to 12 hours per day. The lenses were replaced on a monthly basis in 71% of cases, and 82.8% of wearers used a multipurpose solution for lens cleaning and disinfection. Significant differences were found between first fits and refits regarding the prevalence of dryness symptoms (higher incidence of frequent symptoms in the evening in the refitting group, P<0.01, chi2), replacement schedule (lower incidence of monthly disposable lenses in refits compared to first fits, P<0.05, chi2), and care regimen (lower incidence of multipurpose solutions and higher incidence of hydrogen peroxide in refits, P<0.01, chi2).

CONCLUSIONS

Statistical analysis of the current trends in the Portuguese contact lens fitting profile showed that contact lens practitioners in Portugal are receptive to use innovations in contact lens products, such as silicone hydrogel and biomimetic materials, and daily-disposable contact lenses to refit patients who have not succeeded with previous lenses. Multifocal lenses also experienced a significant increase in their prevalence among refits and new fits. Rigid gas-permeable materials maintained and even experienced a slight increase in refits. Conversely, there is still a low incidence of extended-wear prescriptions, most of them being made with low-Dk soft contact lenses.

Prolonging contact lens wear and making contact lens wear safer

PURPOSE

To summarize the present status of safety and efficacy of contact lens wear.

DESIGN

Literature review.

METHODS

Ovid Medline searches were performed on records from 1966 through 2005 using keywords: keratitis, contact lens complications, extended-wear contact lenses, and silicone-hydrogel contact lenses.

RESULTS

Patients desire comfort, clarity of vision, and prolonged contact lens wear when contact lenses are used to correct refractive error. Practitioners desire patient satisfaction but also require maintenance of the integrity of the eye and no complications that jeopardize vision or health of the eye. Improvements in the oxygen permeability of the contact lens materials, design of the contact lens and its surface, and solutions for the maintenance of the lens have reduced but not eliminated the risks of infection, inflammation, and conjunctival papillary reaction associated with contact lens wear. The lessons of past and recent history suggest that patient education and practitioner participation in the management of contact lens wear continue to be critical factors for patient satisfaction and safety in the extended wear of contact lenses.

CONCLUSIONS

The availability of highly oxygen permeable contact lenses has increased the tolerance and safety of extended contact lens wear, but patient instruction and education in proper use and care of lenses is required and caution is advised.

Comparative Clinical Performance of Rigid versus Soft Hyper Dk Contact Lenses Used for Continuous Wear

PURPOSE

The purpose of this study is to investigate the comparative clinical performance of two hyper Dk contact lenses: a silicone hydrogel lens (Focus Night & Day, Ciba Vision) and a rigid lens (Z-alpha, Menicon Co. Ltd.) when worn for up to 30 days of continuous wear (CW). The rigid lens was worn on an unplanned replacement basis, whereas the soft lens was replaced monthly.

METHODS

One hundred subjects were recruited. Fifty neophyte subjects were randomly assigned into one of the lens types (25 subjects per lens type). Twenty-five existing daily wear (DW) rigid lens users wore the rigid study lens and 25 existing DW soft lens users wore the soft study lens. Visual acuity, lens fit, keratometry, refraction, lens surface assessment, physiological response, and subjective response were investigated at baseline and after 1 week of DW and 24 hours, 1 week, and 1, 3, 6, 9, and 12 months of CW. Analysis compared lens type (rigid vs. soft) and subject group (experienced vs. neophyte).

RESULTS

Sixty-eight subjects completed the study. Visual acuity was similar for the two lens types and subject groups. Lens fit was judged to be adequate in all subjects. Corneal curvature of subjects in the rigid groups became flatter by 0.13 mm compared with 0.04 mm for subjects in the soft lens groups (F = 14.7, p = 0.0003); the refractive findings mirrored these corneal changes. The increasing rate of deposition on rigid lenses was consistent with the fact that these lenses were not replaced during the study. Conjunctival hyperemia and staining were similar for the two lens types but greater among experienced wearers at baseline (F = 13.8, p = 0.0005; F = 5.3, p = 0.02, respectively). Corneal staining was higher for the rigid lens wearers (F = 5.6, p = 0.02) but this was mainly the result of the initial higher scores in the rigid lens experienced group. The change in papillary conjunctivitis was greater for subjects in the soft lens groups than rigid lens groups (F = 4.6, p = 0.04). Comfort was initially lower for the rigid lens neophyte group (F = 4.2, p = 0.0001), but after the CW phase started, there were no differences between groups.

CONCLUSIONS

Notwithstanding subtle differences in physiological responses, continuous wear hyper Dk rigid and soft silicone-containing contact lenses can be successfully worn by both those with previous contact lens experience and those with no history of contact lens wear.

A Hyper-Dk Piggyback Contact Lens System for Keratoconus

PURPOSE

To report the fitting of a hyper-Dk piggyback contact lens system in a case of keratoconus.

METHODS

Case report.

RESULTS

A patient with keratoconus, suboptimal visual acuity, corneal neovascularization, and marked conjunctival hyperemia, who was intolerant of rigid gas-permeable contact lenses, was fitted with a novel piggyback contact lens system that incorporated a hyper-oxygen transmissible hydrogel contact lens, on top of which was fitted a hyper-oxygen transmissible rigid gas-permeable lens. This novel contact lens system provided a significant improvement in visual acuity, comfort, and lens wear time. There was a marked reduction in corneal vascularization and ocular hyperemia.

CONCLUSIONS

This hyper-Dk piggyback contact lens system satisfied the ocular and visual requirements of this patient, for whom other nonsurgical options for vision correction had been unsuccessful. This system has potential application in the visual rehabilitation of other cases of corneal irregularity, including unsuccessful refractive surgery, ocular trauma, and keratoplasty. Piggyback contact lens systems require the same level of expertise to fit as basic forms of soft and rigid contact lenses. The hyper-oxygen transmissible lens materials available make these dual-lens systems a viable option for the compromised cornea.