High Dk piggyback contact lens system for contact lens-intolerant keratoconus patients

Abstract

Background:The aim of the study was to examine the clinical success of high Dk (oxygen permeability) piggyback contact lens (PBCL) systems for the correction of contact lens intolerant keratoconus patients.Methods:Sixteen patients (29 eyes) who were not able to wear gas-permeable rigid lenses were included in this study. Hyper Dk silicone hydrogel (oxygen transmissibility or Dk/t = 150 units) and fluorosilicone methacrylate copolymer (Dk/t = 100 units) lenses were chosen as the PBCL systems. The clinical examinations included visual acuity and corneal observation by biomicroscopy, keratometer reading, and fluorescein staining before and after fitting the PBCL system.Results:Indications for using PBCL system were: lens stabilization and comfort, improving comfort, and adding protection to the cone. Visual acuities increased significantly in all of the patients compared with spectacles (P = 0). Improvement in visual acuity compared with rigid lenses alone was recorded in 89.7% of eyes and no alteration of the visual acuity was observed in 10.3% of the eyes. Wearing time of PBCL systems for most of the patients was limited time (mean 6 months, range 3–12 months); thereafter they tolerated rigid lenses alone except for 2 patients.Conclusion:The PBCL system is a safe and effective method to provide centering and corneal protection against mechanical trauma by the rigid lenses for keratoconus patients and may increase contact lens tolerance.

Improved Vision and Contact Lens Wear Time With Piggy-Back Contact Lens Systems in Children After Penetrating Corneal Trauma

“…Finally, combination systems have lower oxygen permeability compared with single lens systems. This last drawback has been reduced over time as newer high-DK hydrogel and gas permeable materials have become available for use in PB systems 9 . The disadvantages of PB systems are offset by the increased comfort of the system.…”

“…3,4,5 , The use of PB systems have been reported in patients with other causes of irregular astigmatism, including penetrating corneal trauma. 6,7 …”

Contact lens in keratoconus

“…PBCL is indicated in patients with RGP discomfort or intolerance, unstable RGP on the eye, popping out of lens, 3 and 9 O’ clock staining with RGP fit and presence of scar. [1920] A PBCL system is also indicated in some patients to improve comfort.…”

RGP kontakt lenslerin görsel sonuçlarının keratokonus alt gruplarında karşılaştırılması: Kon tipi, kon lokasyonu, hastalığın şiddeti

“…Contact lenses have some advantages over spectacle corrections (3,4). There are several options such as rigid gas-permeable (RGP) contact lenses (5), hybrid contact lenses (6), piggyback lenses (7) and scleral contact lenses (8).…”

“…There are several options such as rigid gas-permeable (RGP) contact lenses (5), hybrid contact lenses (6), piggyback lenses (7) and scleral contact lenses (8). RGP lenses are traditionally first choice because of their success in improving visual acuity (9) RPG lenses improve visual acuity by their refractive power and also by flattening the anterior cornea, increasing the thinnest corneal thickness, and reducing anterior surface high-order aberrations (3,4). Previous studies showed that RGP contact lenses provide a significant improvement in visual acuity compared to spectacles-corrected visual acuity in patients with high corneal astigmatism (10), and keratoconus (11).…”