Features

Truth or myth: Daily disposable hydrogel wearers should be refitted into DD silicone hydrogel lenses?

Contact lenses
This month, in our series looking at common myths concerning contact lenses, Dr Amir Moezzi and David Ruston examine daily disposables

A recent global contact lens (CL) prescribing survey1 showed that silicone hydrogel (SiHy) and hydrogel contact lenses account for approximately 74% and 26% of overall soft lens fits, respectively. This survey also showed that SiHy contact lenses accounted for 78% and 68% of reusable and DD soft contact lens fits, respectively.

This data relates to both new fits and refits and shows that hydrogels are still fitted in just over one in four patients, even though SiHys have been available for over 20 years. Clearly some practitioners believe they still have a role to play in their patient management.

The survey does not, however, inform us about eye care professional (ECP) attitudes and behaviours when faced with a successful happy hydrogel wearer exhibiting no clinical signs. Should they be routinely refitted into SiHys or can they be left in their current material type?

 

Professional Belief Survey Results

A recent online survey2 of over 1,000 independent and retail ECPs in six countries showed that many more (an overall mean of 43%) of ECPs agree (versus 20% who disagree) that they should refit their DD hydrogel wearers into DD SiHy contact lenses, even when there is no obvious clinical reason to do so (figure 1). The exception was in the US where a similar percentage agreed as disagreed with the statement.

 

What the Evidence Shows

Hypoxia induced corneal swelling is a well-known phenomenon and one of the primary indices of corneal physiological compromise during contact lens wear. Several previous studies3-5 showed that SiHy contact lenses induce significantly less corneal swelling than hydrogel contact lenses under closed-eye conditions.

Also, studies have shown an inverse relationship between limbal hyperemia and peripheral lens oxygen transmissibility (from inducing peripheral corneal oxygen deprivation).6,7 Therefore, this data would suggest that there is a clear physiological advantage in replacing hydrogel contact lenses with high-oxygen transmissible SiHy contact lenses in overnight or extended wear conditions.

The same holds true in reducing the risk of corneal oxygen deficiency with either high plus or high minus contact lenses, or any soft contact lenses with a thicker center or edge profile (eg edge profile in prism ballast toric lenses) even in daily wear.8

But, what about the majority of patients with moderate prescriptions who wear contact lenses for daily wear (DW) only? Short-term studies of DW hydrogel contact lenses of low to moderate power reveal no evidence of ocular hypoxic comprise.

A partial double-masked, randomised, bilateral crossover study comparing three DD hydrogel contact lenses and no-lens wear showed no significant differences in topographical corneal swelling and bulbar/limbal hyperemia between the hydrogel contact lens and no lens wear after eight hours.9

In addition, another short-term DW study showed no significant difference in topographical corneal swelling and bulbar/limbal hyperemia after refitting reusable SiHy wearers into a DD multifocal hydrogel lenses for four weeks.10

Similarly, some recent reports found no evidence of ocular hypoxic compromise in long-term daily wear of hydrogel contact lenses. A comprehensive literature review in 2020 showed no signs of hypoxic compromise after wearing hydrogel contact lenses for many years and suggested hydrogel contact lenses are an important alternative for daily wear.11

Furthermore, a 2021 report from a paediatric myopia control study found no evidence of hypoxic problems during six years of DD hydrogel contact lens wear in children aged eight to 12 years.12

 

Conclusion

In summary, the evidence from the literature shows minimal impact on corneal physiology with long-term daily wear of low to moderate power hydrogel contact lenses.

Considering the lower risk of mechanical complications13 and inflammatory adverse events14 with hydrogel contact lenses compared to SiHy contact lenses, along with a lack of any substantial evidence for a difference in comfort between hydrogel and all SiHy materials per se,15 or differences in their risk of developing serious complications such as microbial keratitis,16 existing hydrogel contact lens wearers showing no complications can continue to wear their hydrogel contact lenses successfully. 

  • Dr Amir Moezzi is a lead clinical scientist at the Centre for Ocular Research & Education, School of Optometry & Vision Science, University of Waterloo.
  • David Ruston is director of global professional education at Johnson & Johnson Medical Ltd.

 

References

  1. Morgan PB, et al. International Contact Lens Prescribing in 2021. CL Spectrum 2022;37:32-8.
  2. Johnson & Johnson Vision Care. Online survey of 1028 Eye Care Professionals across United States, United Kingdom, Russia, China, Japan and South Korea. JJV data on file.; 2021 (Russia) and 2022 (other markets).
  3. Fonn D, du Toit R, Simpson TL, Vega JA, Situ P, Chalmers RL. Sympathetic swelling response of the control eye to soft lenses in the other eye. Invest Ophthalmol Vis Sci 1999;40:3116-21.
  4. Bullimore M, Nguyen M, Bozic J, Mitchell G. Overnight Corneal Swelling with 7-day Continuous Wear of Soft Contact Lenses. Investigative Ophthalmology & Visual Science 2002;43:3100.
  5. Fonn DM, A, Simpson, T, Situ, P. Confirmation of a yoked corneal swelling response between the test and contralateral control eye. Optom Vis Sci 2004;81(12S):30.
  6. Papas EB, Vajdic CM, Austen R, Holden BA. High-oxygen-transmissibility soft contact lenses do not induce limbal hyperaemia. Current Eye Research 1997;16:942-8.
  7. Papas E. On the Relationship Between Soft Contact Lens Oxygen Transmissibility and Induced Limbal Hyperaemia. Experimental Eye Research 1998;67:125-31.
  8. Morgan PB, Brennan NA, Maldonado-Codina C, Quhill W, Rashid K, Efron N. Central and peripheral oxygen transmissibility thresholds to avoid corneal swelling during open eye soft contact lens wear. J Biomed Mater Res B Appl Biomater 2010;92:361-5.
  9. Moezzi AM, Varikooty J, Schulze M, Ngo W, Lorenz KO, Boree D, Jones LW. Corneal Swelling with Cosmetic etafilcon A Lenses versus No Lens Wear. Optom Vis Sci 2016;93:619-28.
  10. Moezzi AM, Varikooty J, Luensmann D, Schulze MM, Ng A, Karkkainen T, Xu J, Jones L. The short-term physiological impact of switching reusable silicone hydrogel wearers into a hydrogel daily disposable multifocal. Clin Ophthalmol 2019;13:1193-202.
  11. Efron N, Brennan NA, Chalmers RL, Jones L, Lau C, Morgan PB, Nichols JJ, Szczotka-Flynn LB, Willcox MD. Thirty years of ‘quiet eye’ with etafilcon A contact lenses. Cont Lens Anterior Eye 2020;43:285-97.
  12. Woods J, Jones D, Jones L, Jones S, Hunt C, Chamberlain P, McNally J. Ocular health of children wearing daily disposable contact lenses over a 6-year period. Contact Lens and Anterior Eye 2021;44:101391.
  13. Lin MC, Yeh TN. Mechanical complications induced by silicone hydrogel contact lenses. Eye Contact Lens 2013;39:115-24.
  14. Szczotka-Flynn L, Diaz M. Risk of corneal inflammatory events with silicone hydrogel and low dk hydrogel extended contact lens wear: a meta-analysis. Optom Vis Sci 2007;84:247-56.
  15. Jones L, Brennan NA, González-Méijome J, Lally J, Maldonado-Codina C, Schmidt TA, Subbaraman L, Young G, Nichols JJ. The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens materials, design, and care subcommittee. Invest Ophthalmol Vis Sci 2013;54:Tfos37-70.
  16. Stapleton F, Keay L, Edwards K, Holden B. The epidemiology of microbial keratitis with silicone hydrogel contact lenses. Eye Contact Lens 2013;39:79-85.