Purpose
Extended wear hydrogel contact lenses are used long term following Boston Keratoprosthesis Type 1 (KPro) surgery to reduce the desiccating effects of evaporative tear loss and prevent tissue damage. The initial bandage contact lens (BCL) used at Moorfields Eye Hospital (MEH), inserted at the time of surgery, is a Methafilcon A 55%, base curve 9.6, diameter 16.0mm (Standard lens). This has been used by the Massachusetts Eye and Ear Infirmary since 2000. The Contact Lens Service (MEH) has experienced frequent fitting problems with this BCL. We report the frequency of these problems and measures taken to overcome them.
Methods
A retrospective case note review of all patients undergoing KPro surgery was undertaken from the date of surgery to November 2013. Data was collected on contact lens management throughout this period. A satisfactory BCL fit was defined as having full, bubble -free coverage of the KPro without lens edge fluting. A single mobile bubble was acceptable.
Results
Nineteen eyes of nineteen patients were identified. Two patients were discharged to local services and one patient failed to attend any follow up appointments. Table 1 gives a breakdown of ocular diagnoses for the remaining sixteen. Of the sixteen, five achieved a satisfactory fit with the Standard lens. One patient declined BCL wear due to lens discomfort and elected to have a tarsorrhaphy. The remaining ten patients encountered the following fitting problems:- lens loss (7), edge fluting, poor centration, static bubbles under the lens. Only one patient experienced BCL depositing. A breakdown of refit outcomes is shown in Table 2. High water content hydrogels (Contaflex 75%) were used for the majority of refits. Two patients had tinted lenses (Filcon II 2 67%) to reduce glare and improve cosmesis respectively. Refractive errors were incorporated as required.
Conclusions
In our cohort, we have shown that the Standard lens was successful in 5/16 patients (31%), but that in 10/16 (63%) an alternative BCL specification achieved a satisfactory fit. Further work is required to optimise lens fits following K Pro surgery.
Keywords: 477 contact lens •
575 keratoprostheses