By S. Barry Eiden, OD, FAAO
For many years most practitioners promoted the concept that virtually all patients who suffered from keratoconus would require contact lens correction utilizing rigid corneal lenses. Without a doubt rigid corneal lenses provide excellent visual outcomes based on their ability to “mask” corneal irregularity in the disease. However, clinicians realize that their overall success in managing keratoconus has been limited in many cases by numerous issues, of which #1 would be poor comfort and lens wearing tolerance.
A recent study evaluated the relative performance of a keratoconic hybrid lens design and corneal rigid gas permeable (RGP) lenses. The researchers evaluated a number of performance indicators at a 2-month point following lens dispense to 40 subjects. Results indicated that there was no significant difference in visual acuity measurements between the hybrid and RGP, however a number of other key performance indicators were found to show a difference in performance.
The hybrid lens design demonstrated superiority in overall vision-related quality of life based on the NEI Visual Functioning Questionnaire 25 (P<0.001), comfort (P<0.001) and foreign body sensation (P<0.013). Regarding lens tolerance, the hybrid lens demonstrated borderline superiority (P<0.085).
The purpose of this research review was not to suggest that any one particular contact lens design is superior to others in the management of keratoconus. The intent was to demonstrate that an array of lens designs is now available to address the vision needs of these patients including corneal gas permeable lenses, intralimbal lenses, scleral lenses, piggyback or tandem systems, soft keratoconic lenses and hybrid keratoconic lenses.
Each design has specific and often unique attributes that can address challenges faced by our keratoconic patients. We as contact lens practitioners with special interest and experience in treating the disease need to understand when specific contact lens designs are most appropriate for an individual patient.
Hashemi E, Shaygan N, Asqari S, Rezvan F, Asqari S . ClearKone-SynergEyes or Rigid Gas Permeable Contact Lenses in Keratoconic Patients: A Clinical Decision. Eye & Contact Lens. 2014 March 40(2): 95-8.
Source: Contact Lens Spectrum-Contact Lens Today Newsletter, March 30, 2014