lens case reports
Therapeutic Lenses Past and Present
BY PATRICK J. CAROLINE, FAAO, & MARK P. ANDRé, FAAO
It's difficult to imagine the field of cornea and external disease management before the advent of therapeutic contact lenses. For more than 35 years, these lenses have had an impact on ourpatients' lives on a scale similar to that of antibiotics and corticosteroids.
The story of therapeutic lenses began in Wiesbaden, Germany, in 1887 when master glass blower and prosthetic eye maker Frederick A. Muller was asked to fabricate a protective glass shell for a patient with severe exposure following removal of a malignant lid tumor. As the story goes, the patient continued to wear the glass shell successfully until his death 21 years later.
Fast Forward to Soft Lenses
The modern era of therapeutic lenses began in Prague, Czecho-slovakia, in 1960 when Otto Wichterle began work on what would become the first hydrogel lens material. By the early 1970s, two soft lenses, the Bionite lens from Griffin Laboratories and the SofLens from Bausch & Lomb, were commonly used as therapeutic lenses.
Figure 1a (top). KE's right eye with therapeutic
In May 2003, CIBA Vision received FDA approval for the use of the Night & Day (Dk 170) as a therapeutic lens for two primary indications:
To treat acute or chronic ocular pathologies
To protect the cornea and manage pain following ocular surgery.
Today, an ongoing evolution in lens materials, design and manufacturing has afforded doctors and patients a wide range of therapeutic lens options that include disposable hydrogel lenses, custom hydrogel lenses, collagen shields, scleral and mini-scleral lenses and PMMA scleral (symblepharon) rings.
Besides pain management and mechanical protection, some additional goals of therapeutic lenses include: A vehicle for drug delivery; maintenance of ocular surface hydration; vision enhancement; and occlusion for amblyopia therapy.
Let's look at a case study that demonstrates how silicone hydrogel lenses can be used to treat chronic external diseases.
Patient KE is a 41-year-old woman with a long history of atopic keratoconjunctivitis. At the time of her initial visit in 1994, her best-corrected spectacle acuities were 20/50 in the right eye and 20/60 in the left eye. Slit lamp examination revealed similar findings in both eyes with 360 degrees of peripheral vascularization 2 mm to 3 mm from the limbus, and stromal scarring secondary to multiple Salzmann's nodules. At that time, KE successfully wore GP lenses to correct her surface irregularities, which provided 20/25 correction OU.
KE wore her GP lenses until 1996 when she was forced to discontinue the left lens because of decreasing lens comfort. She continued to wear her right lens, which provided 20/25 vision.
In 2001, KE underwent a penetrating keratoplasty to the left eye and eventually stopped wearing her right GP lens because of declining lens tolerance. Since 2001, her atopic condition has worsened steadily, resulting in declining overall ocular comfort and visual acuity of 20/200 in the right eye and 20/150 in the left eye.
Therapeutic Lens Treatment
left eye with therapeutic lens.
In January 2005, KE's surface disease had worsened, with the corneas showing increased punctate staining and the conjunctiva becoming more hyperemic and chemotic. The decision was made to augment her systemic and ocular treatment with continuous wear therapeutic lenses.
KE was subsequently fitted with Night & Day lenses, right eye, 8.4 +1.50 13.8 (Figures 1a and 1b), and left eye, 8.4 –2.25 13.8 (Figures 2a & 2b). Almost immediately, KE reported improved ocular comfort and vision (20/100 in the right eye and 20/40 in the left eye).
She has worn Night & Day lenses continuously for the past year, and her condition has improved steadily owing to the lenses' therapeutic effect. The patient has reported a dramatic decrease in ocular discomfort and a gradual but significant "whitening" of her eyes over time.
This case illustrates how the continuous wearing of high-Dk silicone hydrogel lenses can dramatically alter the course of chronic external disease conditions, such as atopic keratoconjunctivitis.
Patrick Caroline is an associate professor of optometry at Pacific University and an assistant professor of ophthalmology at the Oregon Health Sciences University.
Mark André is director of contact lens services at the Oregon Health Sciences University and an assistant professor of optometry at Pacific University.