contact
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.
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Figure 1a (top). KE's right eye with therapeutic
lens.
Figure
1b (bottom). KE's right eye. Note the peripheral neovascularization and stromal scars.
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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.
Atopic Keratoconjunctivitis
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
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Figure 2a
(top). KE's
left eye with therapeutic lens.
Figure 2b (bottom). Patient's left eye following penetrating keratoplasty.
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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.
Contact Lens Spectrum, Issue: February 2006