Peripheral Staining and GP Lens Wearers
BY WILLIAM L. MILLER, OD, PHD, FAAO
Corneal staining has received its fair share of discussion lately, so I thought it worthy to look at its occurrence in another clinically encountered situation — GP lens wear.
A frequent finding in GP lens wearers is peripheral staining, also known as 3 o'clock to 9 o'clock staining. In most cases this staining is very superficial. However, there are times when this staining increases in size or depth and may require treatment and modified GP lens parameters.
A more cumbersome side effect from severe peripheral staining is vascularized limbal keratitis, which I discussed in my August column, "VLK in Veteran GP Lens Wearers."
Initial or mild stages of 3 o'clock to 9 o'clock staining may not elicit any symptomatic complaints from patients. However, as the condition worsens or becomes chronic, patients may initially notice redness in the interpalpebral region. Later or severe stages may cause irritation, decreased wearing time and discomfort. The condition worsens in arid environments.
Most of the punctate staining occurs between the 2 o'clock to 4 o'clock and the 8 o'clock to 10 o'clock positions. You'll see fine, solitary areas of staining that may progress to coalesced areas with possible thinning and dellen formation. The latter occurs as the desiccation effects worsen. Clearly, early punctate staining is most visible using a Wratten filter with cobalt light.
Manage the Cause
Many of us agree that intervention may be unnecessary in cases of trace to mild peripheral staining. However, consistent and timely follow-up visits are necessary, as is advising patients to inform your office if their eyes become redder or irritated.
Aim treatment at the causative agent. In some cases this may require discontinuing GP lens wear or refitting with soft lenses. GP design modifications typically correct the edge clearance, which in most instances is excessive, thus requiring a steepening of the peripheral curve radii or a decreasing of the width of the peripheral curve.
Sometimes the staining results from too little edge clearance. This creates a chafing action across the peripheral cornea. Make sure the edges of the lens are smoothly shaped to eliminate this as another source of mechanical irritation.
You may also change the overall GP lens diameter, either increasing the size to cover this area or decreasing it to allow excursion of the lid across the ocular surface. Don't forget other lens choices such as a piggyback system using a silicone hydrogel or hybrid design such as SynergEyes (SynergEyes Inc.), both of which might also be indicated in some of our patients to ameliorate the peripheral corneal staining.
Treating with Lubrication
I also include ocular surface lubrication during the day and night. Options include Blink (Advanced Medical Optics), Aquify (CIBA Vision), Boston Rewetting (Bausch & Lomb) and Thera-Tears Contact Lens Comfort Drops (Advanced Vision Research). I prescribe these during waking hours dependent on the peripheral staining severity.
Nighttime lubrication using Refresh PM (Allergan) or Genteal GelDrops (Novartis) can be a useful adjunctive treatment in more severe cases.
A Less Severe Outcome
I find that following the above recommendations in most cases makes peripheral staining manageable and less severe without resorting to topical decongestants or steroid medications. CLS
Dr. Miller is the Director, Cornea and Contact Lens Service at the University of Houston College of Optometry. He is a member of the American Optometric Association and serves on its Journal Review Board. You can reach him at firstname.lastname@example.org.