Article Date: 11/1/2007

Ethereal Lens Material
contact lens management

Ethereal Lens Material

Silicone-hydrogel may prevent dryness, discomfort and patient dropout.

HARUE J. MARSDEN, O.D.

About half of the 35 million U.S. contact-lens wearers are symptomatic for dryness and discomfort.1 Further, these patients more commonly experience these symptoms at the end of their lens-wearing day, indicating that the lenses themselves, and not other dry-eye-associated factors, are the culprit. Something else to consider: Patients have blamed dryness and discomfort for discontinuing contact-lens wear.2

I've found that the best way to prevent this cause of contact-lens dropout is to offer patients a silicone-hydrogel contact lens. Silicone-hydrogel lenses not only offer higher oxygen permeability than traditional HEMA lenses, but also demonstrate less dehydration than high-water content lenses.3,4 The result: less hypoxia, improved signs of corneal health and improvement in dry-eye symptoms.5 My lens choice for patients who experience persistent contact lens-related dryness: Night & Day, from CIBA Vision.

Material difference

Night & Day lenses have a 24% water content and a Dk/t value of 175. A recent long-term study (three years) revealed that the combination of these two attributes may alleviate dryness symptoms.

The study was comprised of 278 low Dk/t conventional-lens wearers who were refit with Night & Day lenses for continuous wear for up to 30 nights. Results showed that one week after refitting, reports of dryness during the day decreased from 57% to 33%. In addition, reports of end-of-day dryness decreased from 61% to 41% by one week. Further, reduction in dryness symptoms remained stable through three years (p<0.0001 for all comparisons).

Patients reported the frequency and intensity of dryness symptoms during- and at the end of the day via questionnaires at baseline, one week and through three years of follow-up.

The purpose of the study was to assess the stability of dryness symptoms post-refitting and whether early dryness symptoms predicted cessation in the study.6

Specific patient benefits

I've found that Night & Day lenses can benefit three types of patients, in particular:

Workaholics/late-shifters. Because these lenses are Food and Drug Administration (FDA)-approved for up to 30 nights of continuous wear, they're often perfect for patients who work overnight shifts or whose jobs require long hours of uninterrupted work.

Presbyopes. These patients often have decreased tear production as a result of age, hormonal changes and use of antihypertensive medications, among other drugs.7-10 As a result, many of them appreciate the end-of-day comfort and moisture that these lenses provide. Further, their high Dk/t value ensures that more oxygen transmits through the lens, despite the fact that these patients' prescriptions require their lenses to be thicker in the center.

Night & Day
MATERIAL: lotrafilcon A
WATER CONTENT: 24%
DK/T: 175 @ -3.00 D
WEARING SCHEDULE: daily wear and up to 30 nights continuous wear (also indicated for therapeutic use — www.accessdata.fda.gov/scripts/cdrh/devicesatfda/index.cfm?db=PMA&id=4344)
RECOMMENDED REPLACEMENT
SCHEDULE:
monthly
DIAMETER: 13.8mm
BASE CURVES: 8.4mm and 8.6mm
POWERS: 6.00D to -8.00D (0.25D steps); -8.50D to -10.00D (0.50D steps)
CONSUMER COST: $49.50 (six pack), according to "Tyler's Quarterly Soft Contact Lens Parameter Guide," Sept. 2007

Children. Teenagers and adolescents have decades of wearing time ahead of them. To help prevent potential physiological changes, such as stromal thinning and endothelial polymegethism, that can occur with lower transmissibility lenses, I immediately offer these patients a high Dk/t silicone hydrogel lens.11

Children often appreciate Night & Day's monthly replacement schedule.

In addition, I've found that it's often easier for younger patients to comply with Night & Day's monthly replacement schedule, as opposed to lenses that require more frequent replacement. This is because this patient population can often depend on their parents and/or electronic communication devices to offer monthly reminders.

I currently fit 16% of my contact-lens patients in this lens. Due to patient reports of fewer symptoms of dryness, increased comfort for longer periods of time and clearer, whiter-looking eyes, I have no doubt this number will increase.

Further, out of the thousands of patients I've fit in a silicone-hydrogel lens, fewer than 10 have dropped out due to ocular health or comfort reasons. OM

References furnished upon request.


DR. MARSDEN IS AN ASSOCIATE PROFESSOR AT THE SOUTHERN CALIFORNIA COLLEGE OF OPTOMETRY AND CHIEF OF ITS STEIN FAMILY CORNEA AND CONTACT LENS CENTER.



Optometric Management, Issue: November 2007