Managing PMD with a Semi-scleral Contact
PATRICK J. CAROLINE, FAAO, & MARK P. ANDRé, FAAO
In past columns we've discussed a wide range
of contact lens modalities for managing pellucid marginal degeneration (PMD), including
aspheric GPs, piggyback lenses, toric soft lenses and bitoric GP designs. This month we'll review the use of the Jupiter Lens (Medlens Innovations,
Inc., also distributed by Essilor) in managing one of these complex corneas.
PMD is often a bilateral disorder hallmarked by a thinning of
the inferior, peripheral cornea. The corneal thinning begins approximately 1mm to
2mm above the inferior limbus, separated by a region of uninvolved cornea that lies
between the thinned zone and the limbus. The condition commonly manifests itself
between the ages of 20 and 40 with equal gender distribution and no apparent hereditary
transmission. Subjective symptoms are strictly visual secondary to a dramatic increase
in against-the-rule corneal astigmatism.
can manifest many of the same features as keratoconus, but in PMD the central and
paracentral cornea retains a normal thickness. In PMD, the corneal mapping demonstrates
inferior midperipheral zones of corneal steepening at 4 o'clock and 8 o'clock
that produce a butterfly wing-like or kissing pigeons pattern that's diagnostic
Fitting the Jupiter Lens
Patient JM is a 40-year-old male with a 15-year history of PMD.
His more-involved right eye with Ks of 36.75 @ 86/ 47.12 @176 had become uncomfortable
in his current lens due to excessive lens rocking at 4 o'clock and 8 o'clock secondary
to the high degree of against-the-rule corneal astigmatism (Figure 1). We suggested
that JM might benefit from the stability of a Jupiter mini-scleral lens design.
We selected a 15.0mm diagnostic lens with a base curve radius
equal to the steepest K read-
ing. We placed two drops of fluorescein into the
bowl of the lens prior to lens application and adjusted the base curve (steeper
or flatter) until we achieved slight apical clearance and feather inferior touch
across the inferior ectasia. The scleral skirt should align with an edge that rises
just above the scleral epithelium (Figure 2).
We determined the lens power by a spherical over-refraction. JM
ultimately achieved a visual acuity of 20/25 and is able to wear the lens comfortably
throughout all his waking hours.
Patrick Caroline is an associate
professor of optometry at Pacific University and is an assistant professor of ophthalmology
at the Oregon Health Sciences University. He is also a consultant to Paragon Vision
Sciences and SynergEyes, Inc. Mark André is an associate professor of optometry
at Pacific University. He is also a consultant for Alcon Labs, CooperVision and
Contact Lens Spectrum, Issue: January 2007