Silicone Hydrogel Contact Lenses

 Hit or a Myth? 

Your eye-sight is precious so make sure you wear contact lenses that allow the necessary flow of oxygen (20 Dk units) to your eyes but make sure no one hits your pocket with a myth!

Silicone hydrogel (SiH) contact lenses can have flow rates 10 times the recommended minimum of 20 (ie 200 Dk units) but the actual oxygen getting to the endothelium (where it is used by the eye) is exactly the same as for a lens with a Dk of 20.

Don’t fall for the myth which encourages you to pay more for something giving no additional benefit.  daysoft® lenses with a Dk of 26 hit the bulls-eye.

There is also a Silicone side-effect … they are ‘harder’ and it is now of concern that this causes ‘mechanical complications’.  A recent round-table discussion conducted by Optician magazine for opticians resulted in these comments:  I fit a lot of daily disposables lenses and we’ve not been happy fitting SiH daily disposables.  We see lid changes after a year or two.  We’ve all patients who we’ve put into SiHs and for one reason or another it hasn’t worked so we’ve gone back to hydrogels.  …. in daily disposables the SiHs are hit or miss in the comfort factor.”

The bottom line …. SiH lenses have not increased the market despite huge research expenditures.

daysoft® contact lenses contain no silicone.  They provide all the oxygen required for normal daily-wear  and are uniquely affordable and soft for great comfort.

Why pay £44 a month for 1-day silicone lenses?    Switch from today,27th May 2013 to daysoft® using  www.daysoft.com  for £12.48 a month (2 Boxes of 32 lenses delivered  now).

 

BACKGROUND ANALYSIS

Recent Scientific Papers (2012/2013)

Complications from SiH wear have continued to be reported, despite significant efforts to reduce stiffness and improve wettability of the materials.Reporters now conclude that SiHs have not grown the market, have not improved comfort and due to higher modulus and reduced drape can mechanically damage the surface of the eye.

The 2013 paper, Mechanical Complications Induced by Silicone Hydrogel Lenses, cites the varied complications as:-

  • Mucin Balls (which cause dents in the corneal surface)
  • SEALs ( lesions caused by the stiff lens abrading the eye)
  • Corneal Epithelial Erosion ,Induced Papillary  Conjunctivitis, Conjunctival Epithelial Flaps, Lid Wiper Epitheliopathy and Meiobium Gland Dropout

It is important to note that such complications occur with SiH lenses irrespective of wear modality or type of cleaning solution used. In a 2012 paper Brien Holden reports that TruEye (Narafilcon A) Daily Disposable lenses displayed higher levels of mechanical complications than a conventional hydrogel lens. Even the state of art SiH material is still prone to complications, and the jury remains out on the longer term adverse effects. 

Other Recent Scientific Papers (2012/2013)

Complications from SiH wear have continued to be reported, despite significant efforts to reduce stiffness and improve wettability of the materials.  Reporters now conclude that SiHs have not grown the market, have not improved comfort and due to higher modulus and reduced drape can mechanically damage the surface of the eye.

 

The 2013 paper, Mechanical Complications Induced by Silicone Hydrogel Lenses, cites the varied complications as:-

  • Mucin Balls (which cause dents in the corneal surface)
  • SEALs ( lesions caused by the stiff lens abrading the eye)
  • Corneal Epithelial Erosion ,Induced Papillary  Conjunctivitis, Conjunctival Epithelial Flaps, Lid Wiper Epitheliopathy and Meiobium Gland Dropout

It is important to note that such complications occur with SiH lenses irrespective of wear modality or type of cleaning solution used. In a 2012 paper Brien Holden reports that TruEye (Narafilcon A) Daily Disposable lenses displayed higher levels of mechanical complications than a conventional hydrogel lens. Even the state of art SiH material is still prone to complications, and the jury remains out on the longer term adverse effects.