contact lens practice pearls
Silicone Hydrogels: Help or Hype?
BY THOMAS G. QUINN, OD, MS, FAAO
With so much excitement in the eyecare arena about silicone hydrogel contact lenses, I was surprised to find that more than a quarter of the nearly 4,000 respondents to a clspectrum.com survey don't prescribe them! Why not? Although not perfect, silicone hydrogels can benefit patients in many ways.
Currently available silicone hydrogel lenses offer more oxygen to the corneal surface than their hydrogel lens predecessors. You could fit virtually any silicone hydrogel lens to solve hypoxic-related problems such as myopic creep, corneal microcysts, striae and neovascularization, as well as conjunctival injection. Patients readily observe and often greatly appreciate conjunctival redness reduction. Don't underestimate the importance of this cosmetic benefit to silicone hydrogel contact lens wear.
Improved oxygen profiles of silicone hydrogel lenses can benefit virtually all patients, even daily wear patients. Although perhaps more helpful in higher prescriptions or prism-ballasted designs, the added oxygen comes in handy when daily wear patients occasionally nap or sleep overnight in their lenses. We know it happens. In fact, I no longer ask patients "if" they sleep in their lenses, I ask "how often."
Patients often report they can comfortably wear soft contact lenses for six to eight hours, but then the lenses start to feel gritty, irritated or dry. This increased awareness causes some to return to spectacle wear full time. In fact, discomfort is the number-one reason for discontinuing contact lens wear.
CIBA Vision developed its O2Optix lens to relieve late-day discomfort associated with hypoxic stress that may develop with hydrogel lens wear. Vistakon's Acuvue Advance material has the same goal, but attributes its ability to achieve all-day comfort not only to increased oxygen, but also to its moisture-retaining agent Hydraclear. Regardless of the approach, silicone hydrogels can play a vital role in preventing dropout due to discomfort.
PureVision (Bausch & Lomb) and Night & Day (CIBA Vision) lenses crank the oxygen flux up high enough to allow continuous lens wear for up to one month. Studies by Jason Nichols, OD, MPH, PhD, and others demonstrate a clear patient interest in this option that increases significantly when eyecare providers express support for this modality.
I tell my continuous wear candidates that, although approved for up to one month of wear, factors such as tear quality and work environment may limit their wear time, even possibly to daily wear. I then emphasize the importance of monitoring their response to the lenses to ensure good vision, comfort and safety.
What's the Problem?
So why isn't everyone fitting silicone hydrogel lenses? Reasons vary from price concerns to worries about mechanical problems induced by these higher-modulus lenses. Many articles and presentations about silicone hydrogels go to great lengths to discuss conditions such as epithelial splitting and lens-induced papillary changes to the superior tarsal plate.
These phenomena can and do occur, but be careful not to throw the baby out with the bath water. Don't avoid the positive features of silicone hydrogels for fear of what problems may arise. With proper fitting, instruction and monitoring, silicone hydrogel lenses can offer your patients benefits that hydrogel lenses aren't able to provide. If you haven't already, I encourage you to share these benefits with your patients.
Dr. Quinn is in group practice in Athens, Ohio, and has served as a faculty member at The Ohio State University College of Optometry.