Aimee McWilliams presumed that her routine contact lens check-up would turn-out to be merely a formality. The 33-year-old fashion designer from London had always worn contacts since age 14, and never had any trouble with them. Opticians advise using contacts for less than eight hours in a day. Aimee, crossed the set limit – by putting them on for more than 14 hours.
She had slowly been cutting oxygen supply to her eyes – whilst the impairment wasn’t visible to the naked eye, it was detected when the optometrist made use of a purpose-built microscope. It was a shock for Aimee after she learned that she was at a high risk of losing her vision. ‘I was scared,’ recalls Aimee. I have been using my lenses from 7 am till midnight daily – and nobody ever warned me about the peril of losing vision.
‘What made it more scary was that there were no signals pointing anything wrong – my eyes looked perfect. In fact I delayed my annual check-up by several weeks as I felt there was no real need of it. Nearly 3.7 million people in Britain use contacts. But many don’t think much of how careful you got to be about using them, says Hosam Kasaby, a consultant ophthalmic surgeon at Southend University Hospital and BMI Southend Hospital.
A potential risk is corneal neovascularisation, the exact same condition that Aimee had. Mr Kasaby clarifies: ‘The transparent outer layer at the fore-end of the eyeball called cornea is the lone part of the body, that receives oxygen supply directly from the air rather than from the blood.
‘But contact lens blocks that oxygen supply, so over-use can potentially starve the cornea of oxygen. The body offsets this by making new blood vessels over the cornea to deliver oxygen, called corneal neovascularisation. ‘If it carries on without check the eye gets caked with blood vessels, and turns the cornea opaque. In a few cases it can endanger vision.
Refraining from using lenses can make the new blood vessels to collapse, however, in acute cases when excessive blood vessel growth occur, even if they collapse, they can cause scarring.
Corneal neovascularisation is witnessed commonly with standard soft lenses, which are formed out of water-carrying plastic. The other lens type, gas permeable, although less flexible, permit more oxygen, says Robert Glass, a Manchester-based optometrist. ‘The latest soft lenses, known as silicone hydrogels, permit more oxygen to cross over to the cornea – so are a lot healthier,’ he adds.
Corneal neovascularisation is not the lone problem-causer with wearing contacts for too long. Lucia Paovesana, 27, wore contacts for more than 10 hours a day – it ruined her big, round blue eyes. The whites of her eyes now stay red and sore. A specialist at Ashfurlong Medical Centre in Sutton Coldfield, diagnosed her with blepharitis – inflammation of the eyelids – brought on by over use of contacts. Blepharitis results in reddening of the whites of the eye. There’s as such no cure for this condition, however, it can be managed by washing eyes with boiled water.
And, strangely, some patients are under the impression that they’re keeping a good hygeine, but aren’t, asserts David Anderson, consultant ophthalmic surgeon and corneal specialist at University Hospital Southampton. ‘Some people habitually wash hands before putting on lenses – and unintentionally don’t dry their hands properly – thus expose themselves to a bug called acanthamoeba.
To avoid infection refrain from swimming or using a hot tub or shower with contacts on, cautions Jeff Kwartz, consultant ophthalmic surgeon at the Royal Bolton Hospital. ‘And never hold them under running water.’