A patient who has only one functional eye (and an eye prosthesis OD) keeps us busy. After developing corneal erosions with (R)GPs, we fitted him in 2008 with a first-generation hybrid lens, which resulted in circle-shaped erosions. In an attempt to resolve this, we fitted the patient with a scleral lens in 2010. This worked well for some time until the patient developed recurrent conjunctivitis, which turned us again toward (R)GP lenses and later to a new hybrid lens. The patient was satisfied with the latter modality, but we remained cautious because of the presence of circle-shaped impression rings on the corneal surface, especially because it is the patient’s only functional eye. We then tried fitting him with a piggyback lens system from an American company (X-Cel Contacts, Atlanta GA, USA).
First we applied the appropriate soft lens, which had an optimal lens fit with slight movement, and then we performed Pentacam topography over the lens surface. The resulting topography image (see figure 1) was similar to the topography image without the lens, except the pachymetry (thickness map) showed an increase of about 240µm because of the lens thickness.
Figure 1: Corneal topography without Piggyback lens (left) with Piggyback lens (CHU Liege)
The soft piggyback lens used has an anterior cut-out that is about 10.20mm wide. It helps provide better (R)GP lens centration, better comfort for the patient and it also prevents the (R)GP lens from slipping away from the soft lens portion. For the (R)GP lens portion, we used the patient’s old (R)GP lens, which happened to have the right diameter.
Figure 2: OCT image with the cornea (bottom), anterior cut-out piggyback lens (middle) and the (R)GP lens on top. (CHU Liege)
The patients’ vision (0.8) is the same as with the (R)GP alone, but the comfort is much better and the recurrent corneal erosions are no longer an issue.
Piggyback is still a valid contact lens modality, and with the Piggyback lens with the anterior cut-out, it is even better.
This begs the question: Is Piggy-Back?
Jan Pauwels completed his education as an optician/optometrist in 2006 in Brussels (BE). He worked at several optical practices before starting his own contact lens practice. Currently, he is the owner of Lens Optical Technology, which consists of 10 different practices in Belgium including three university hospitals: UZA Antwerp, UZG Gent and CHU Liège. Jan is also lens distributer in Belgium for Specialty Lens Company. He specializes in fitting contact lenses on irregular corneas and has fit hundreds of patients with scleral lenses in the last year alone. He is a clinical investigator for a number of companies and is involved in research and development of new scleral lens devices.