Piggyback Fitting in a Keratoconic Patient with Dry Eyes: Julie DeKinder, OD, FAAO, FSLS
Background
Patient RP, a 40-year-old white male presented with a chief complaint of very irritated and dry eyes for the last four months. He was diagnosed with keratoconus in 1990 and had a penetrating keratoplasty(PK) on the right eye in 1993. He presented wearing an unknown design in the following parameters:
| OD | OS | |
| Base Curve Radius (BCR): | 6.28mm | 6.30mm |
| Power: | -16.50D | -15.75D |
| Overall Diameter (OAD): | 8.70mm | 9.30mm |
Test Procedures, Fitting/Refitting, Design & Ordering
Entrance Visual Acuities (with Current Contact Lenses):
OD: 20/20
OS: 20/25
Manifest Refraction:
OD: -12.75 -2.75 x 125 20/30
OS: -19.00DS 20/80
Corneal Topography Sim Ks (Medmont):
OD: 48.7 @ 174; 52.3 @ 084
OS: 52.4 @ 015; 56.4 @ 105
Slit Lamp Examination (with Contact Lenses):
OD: exhibited an apical clearance (central 3mm) fluorescein pattern with midperipheral bearing and excessive edge clearance.
OS: exhibited an apical bearing fluorescein pattern with 3mm of central bearing accompanied by midperipheral pooling with excessive edge clearance. The contact lens rested on his lower lid and dislodged from his eye three times after the blink during his initial visit.
Slit Lamp Examination:
OD: central Grade 2+ superficial punctate keratitis (SPK); 4-5 small, circular staining defects consistent with an apical clearance fitting relationship:
- stromal edema Grade 2
- 2mm circular sub-epithelial scar tissue 2 mm inferior to visual axis
- Grade 2 neovascularization 360˚ encroaching on PK margin
- poor tear film with grade 3 conjunctival staining
- OS: – 4mm x 2mm white opacity/scar with elevated, scalloped borders extending into stroma 3 mm inferior to the visual axis
- poor tear film with grade 3 conjunctival staining
Diagnostic Fitting:
OD: Lens selection for the right eye was relatively straightforward. The median keratometry values were used to select the initial diagnostic lens.
| Type | BCR(mm) | Power(D) | OAD(mm) | |
| OD: | Dyna Intra-Limbal | 6.62 | -7.37 | 10.80 |
Over-Refraction/Visual Acuities:
OD: -6.00D (vertexed): 20/30
This lens — with a -13.37D power — was dispensed but ultimately within (??? months) resulted in apical bearing, excessive edge clearance (???) and adherence. He was changed to a smaller diameter, steeper base curve radius lens: Dyna Z (Lens Dynamics) in the following parameters (with power compensation for changing to a steeper base curve radius):
| Type | BCR(mm) | Power(D) | OAD(mm) | |
| OD: | Dyna Z | 6.20 | -17.25D | 8.80 |
This lens resulted in good centration and an evenly distributed fluorescein pattern. Visual Acuity with an over refraction was 20/25.
OS: Lens selection for the left eye proved to be more difficult, due to the steepness of the cornea and the inferior placement of the cone. The initial trial lenses were an intralimbal design selected from median keratometry values. Two lenses of this design were trialed, both lenses exhibited excessive apical bearing with poor centration and excessive edge clearance. The next five lenses trialed were the Tru-Kone (Tru-Form Optics) design. The smaller diameter centered well over the cone without excessive edge lift. The following lens was ordered:
| Type | BCR(mm) | Power(D) | OAD(mm) | |
| OD: | Tru-Kone | 5.30 | -26.50D | 8.70 |
With slit lamp evaluation at dispensing, this lens exhibited apical clearance and moved well with the blink although it did exhibit some inferior decentration.
One Month Follow-up Visit:
This patient was satisfied with the right lens; however, he was experiencing some discomfort with the left lens – Acuvue Advance (Vistakon) 8.3/-0.50 20/20
A piggy-back system was initiated at his one month follow-up to increase patient comfort. RP had complaints of dryness and irritation in the left eye secondary to dry eye. To increase comfort an Acuvue Advance (Vistakon) lens is worn under the Tru-Kone.
Dry Eye Treatment:
Patient was initially treated with FML ophth sol qid OU, Restasis ophth emulsion bid OU, and Artificial tears PRN OU for 1 month. After the initial treatment FML was discontinued, but the patient continued Restasis and AT as described above.
Patient Consultation and Education
The key factors with this patient are to not only fit the patient in a lens that stays on the eye but also treat the underlying cause of lens discomfort, chronic dry eye disease.
Follow-Up Care/Final Outcome
In the case of RP, the solution to increased wearing time and comfort was two-fold. He first needed to be refit into a set of lenses that would stay on the eye and provide the best visual acuity. Secondly, we needed to control his dry eye symptoms. Dry eye syndrome is becoming easier to treat with the many medical advances. The first set was to increase lens comfort in the left eye with a piggyback system. A steroid pulse in combination with Restasis has effectively managed RP’s dry eye. He currently wears his lenses approximately 16 hours a day with no complaints.
At his 6 month follow-up visit, RP presented with no complaints. He continues to use Restasis OU for his dry eye. His vision is 20/25 OD, OS at distance. The lens-to-cornea fitting relationship is described below for each eye.
OD: alignment fit, 1mm movement, centered on cone
OS: Tru-Kone: alignment fit, 1mm movement, inferiorly decentered (on cone)
Acuvue Advance: slightly tight fit, minimal movement, centered over pupil
Discussion/Alternative Management Options
Chronic dry eye disease (CDED) is a condition caused by many factors that result in inflammation of the eye and the tear-producing glands. Inflammation can decrease the eye’s ability to produce normal tears that protect the surface of the eye and keep it moist and lubricated. The inflammation causes T-cell activation, as a result, cytokines gather on the ocular surface. The cytokines cause changes that decrease tear production, corneal desiccation, and other dry eye symptoms. Simply using artificial tears or punctal plugs are not the answer to alleviate this type of dry eye. These treatments will not remove the cytokines from the ocular surface.
Cyclosporine 0.05% (Restasis, Allergan) is the first drug shown to increase tear production. Cyclosporine specifically targets an underlying pathology of dry eye disease: Immune-mediated inflammation. It is important to note that Restasis usually does not show a result until after approximately 4 weeks of treatment and can take up to as many as 12 weeks. This is why many will initiate a steroid (FML, Lotemax) with the Restasis for a more immediate response. The steroid can easily be tapered after 2 to 4 weeks of use.
Supplemental Readings
- Bennett ES, Cutler S. Keratoconus. In Bennett ES, Hom MM. Manual of Gas Permeable Contact Lenses (2nd ed.). Elsevier Science, St. Louis, MO, 2004:190-211.
- Caffery B, Paugh J. Tears, Dry eye, and Management. In Bennett ES, Weissman BA. Clinical Contact Lens Practice (2nd ed.).
Lippincott Williams & Williams, Philadelphia, PA, 2005: 277-294. - Morris S, Davis J. Relief for Contact Lens-related Dry Eye. Contact Lens Spectrum 2006;21(1):42-43.
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