In today’s world, soft contact lenses are fit much more often compared to GP lenses. Some of the many reasons for this include initial comfort, daily disposability, and advanced materials and designs. Current soft lens materials have high oxygen permeability and good surface wetting characteristics, both of which are necessary for successful wear. Advances in technology have allowed manufacturers to produce excellent designs with great reproducibility. For most patients who have regular refractive errors, and for some who have irregular corneas, soft lenses are their best options to attain the best balance of vision, comfort, and eye health.
Yet, GP lenses have not gone away and in fact have enjoyed a healthy return to 10% of contact lens fits/refits in 2016 after dipping to 6% a few years ago (Nichols, 2017). Why this resurgence in GP fitting?
Four Reasons to Fit GPs
- Superior Vision GP lenses are still superior to soft lenses in one major aspect: vision. Vision is the most important factor for many contact lens wearers, so those who require or desire the best visual quality will opt for GP lenses. The main obstacle is the required adaptation with corneal GP lenses.
- Improved Technologies for Comfort Scleral lenses have significantly reduced and in some cases eliminated the need for adaptation because their large size and lack of movement result in good initial comfort. Sclerals can mask the majority of the corneal irregularities, deliver excellent visual acuity, and they are comfortable from the start. They also help combat ocular surface dryness by bathing the cornea with fluid during wear.
Hybrid lenses provide crisp GP optics with the comfort of a soft lens. Finally, surface coatings and treatments can improve GP wettability and comfort.
- Myopia Control with Orthokeratology (OK) Another area that is gaining in popularity is overnight OK. OK has been around for decades, but not until recently has OK become a popular method for myopia and astigmatism correction.
In addition to correcting refractive error, OK is an effective off-label method for controlling myopia progression in children (Huang et al, 2016; Walline, 2016), addressing a growing public health issue. As our knowledge of the mechanisms of myopia development and OK lens technology grows, so will this segment of the contact lens industry.
- Crisp Presbyopia Optics Presbyopes have historically been disappointed with the available contact lens options. Soft multifocals have advanced greatly over the years but still rely solely on simultaneous vision, which is always a compromise.
Many GP multifocals use simultaneous vision, but they are also able to incorporate some alternating vision. When working properly, alternating vision delivers the best vision at distance and near because patients look almost exclusively through one power zone at a time. Also, due to their rigid nature, GP lenses can provide sharper and more stable vision, even with multifocal optics. Some scleral and OK designs incorporate multifocal optics, further expanding their potential for a wider range of patients.
The Bottom Line
GP lenses will continue to have an edge in visual performance over soft lenses, especially for those who have ocular surface issues. With new design options continually being developed, we can look forward to more GP tools to help our patients in the future. CLS
For references, please visit www.clspectrum.com/references and click on document #263.