Keratoconus

"Keratoconus is a vision disorder that occurs when the normally round cornea becomes thin and irregularly cone shaped. This abnormal shape prevents the light entering the eye from being focused correctly on the retina and causes distortion/blurring of vision.

In its earliest stages, keratoconus causes slight blurring and distortion of vision and increased sensitivity to glare and light. These symptoms usually appear in the late teens or late twenties. Keratoconus may progress for 10-20 years and then slow in its progression. Each eye may be affected differently. As keratoconus progresses, the cornea bulges more and vision may become more distorted. In a small number of cases, the cornea will swell and cause a sudden and significant decrease in vision. The swelling occurs when the strain of the cornea's protruding cone-like shape causes a tiny crack to develop. The swelling may last for weeks or months as the crack heals and is gradually replaced by scar tissue. If this sudden swelling does occur, your doctor can prescribe eyedrops for temporary relief, but there are no medicines that can prevent the disorder from progressing.

Eyeglasses or soft contact lenses may be used to correct the mild near sightedness and astigmatism that is caused by the early stages for keratoconus. As the disorder progresses and cornea continues to thin and change shape, rigid gas permeable contact lenses can be prescribed to correct vision adequately. In most cases, this is adequate. The contact lenses must be carefully fitted, and frequent check-ups and lens changes may be needed to achieve and maintain good vision.

In a few cases, a corneal transplant is necessary. However, even after a corneal transplant, eyeglasses or contact lenses are often still needed to correct vision."

New study finds resistant organisms at core of soft contact lens corneal infections

"In 2006, Bausch & Lomb withdrew its ReNu with MoistureLoc contact lens solution because a high proportion of corneal infections were associated with it. Now in a new study from a US university researchers show that these infections were fueled and made resistant to treatment by the formation of a highly resistant structure of microbial cells held together with a glue-like matrix material, what scientists call ‘biofilms’.

“Once they live in that type of state, the cells become resistant to lens solutions and immune to the body’s own defense system,” said Mahmoud Ghannoum, director of the Center for Medical Mycology at University Hospitals Case Medical Center, Cleveland and senior investigator of the study which appears in the January 2008 issue of the journal Antimicrobial Agents and Chemotherapy.

“This study should alert contact lens wearers to the importance of proper care for contact lenses to protect against potentially virulent eye infections,” he said.
“Biofilms are a constellation of resistant organisms.”

They were suspected with the spate of infections in 2005-2006, but until this study, there were no data to prove this.
This is the first in-vitro model for cornea keratitis infections caused by the fungus Fusarium, which was one of the main culprits in the ReNu with Moisture Loc cases, and another fungus called Candida albicans.

The researchers also discovered that the strain of fungus (ATCC 36031) used for testing the effectiveness of lens care solutions is a strain that does not produce biofilms as the clinical fungal strains do. Lens care solutions currently are tested against an old and rare genotype fungal strain obtained in the 1970s from a patient from Nigeria. The contact lens solutions, therefore, are effective in the laboratory, but fail when faced with strains in real-world situations. “The multipurpose contact lens solutions cannot kill these germs, to put it simply,” said Dr. Ghannoum.

“We recommend that solutions be tested for biofilms produced by more recent clinical isolates,” said Dr. Ghannoum. “One of the underlying reasons for ReNu with MoistureLoc not being effective against the outbreak of keratitis is that the solution is not effective against biofilms and the organisms contained in biofilms.”

The researchers tested six kinds of contact lenses made by three different manufacturers and two lens care solutions (Bausch & Lomb’s MoistureLoc and MultiPlus) against three fungal strains (two recent clinical strains and the one from the 1970s) of Fusarium and one strain of C. albicans.

Since biofilm contamination of contact lens cases is a common finding, and ReNu with MoistureLoc is ineffective against fungal biofilm, the industry must ensure that their multipurpose solutions are effective against biofilms, said Dr. Ghannoum. In the meantime, extreme caution must be taken to ensure the contact lens care case is not contaminated with biofilm.

Dr Ghannoum recommends that soft contact lens wearers use only fresh lens care solution, not add fresh solution to old solution, a phenomenon known as topping off, and use solution by expiration dates written on the package. He also recommends a rub and rinse method, regardless of which cleaning or disinfecting solution used (which also is recommended by the Centers for Disease Control and Prevention).

An additional preventative measure to prohibit the development of biofilms is to ensure that the bottle caps and tips of multipurpose solutions are clean."

Bio-films make eye infection hard to treat

"Soft contact lens wearers need to be aware of how to fight the formation of a constellation of resistant organisms called bio-films, a U.S. study said.

Researchers at the University Hospitals Case Medical Center in Cleveland said bio-films -- microbial structures held together by a glue-like matrix -- make corneal infections hard to treat.

'Once they live in that type of state, the cells become resistant to lens solutions and immune to the body's own defense system,' study senior investigator Mahmoud Ghannoum said in a statement. 'This study should alert contact lens wearers to the importance of proper care for contact lenses to protect against potentially virulent eye infections.'

The study also found contact lens solutions need to be made effective on new micro-organism strains and in particular on bio-films. Ghannoum recommends soft contact lens wearers use :

• Fresh lens care solutions only and never add fresh solution to old solution.
• Solution that has not passed the expiration date on the package.
• Soap and water to wash hands and drying them before handling lenses.
• The rub and rinse method instead of the no-rub method
• Caution to ensure bottle caps and tips of multipurpose solutions are always clean."

Pharmacists warned over plano Contact Lenses sales

"The Royal Pharmaceutical Society of Great Britain has advised pharmacists that they must not sell plano cosmetic contact lenses unless they are sold under the supervision of a registered optometrist, dispensing optician or doctor.

In its latest Law and Ethics Bulletin, the RPSGB informs those pharmacists wishing to sell plano lenses that they must do so in accordance with the relevant legal requirements set out in the 1989 Optician's Act. It refers them to a statement made by the General Optical Council in October 2006 clarifying the sale and supply of optical appliances."

Acanthamoeba Keratitis

"Acanthamoeba is a microscopic, water-borne, parasite that may invade the cornea, causing a potentially devastating ocular condition known as Acanthamoeba keratitis. The infection occurs almost exclusively in contact lens wearers. The primary risk factors for this condition are: swimming in pools, lakes or sea water while wearing contact lenses, storing contact lenses in home made solutions including tap water, and poor contact lens hygiene.

This condition is typically accompanied by severe pain, redness, and scant (if any) discharge. The diagnosis must be considered in patients with risk factors who also present with corneal infiltrative deposits or ulceration - especially those in which the condition fails to resolve with traditional antibiotic therapy. The diagnosis is confirmed with a microscopic examination of the cells taken from the cornea, using specialized laboratory staining techniques.

If the diagnosis is confirmed, treatment with multiple antibiotics including antifungals is generally initiated, and hospitalization is often necessary. Some patients incur severe corneal scarring and require corneal transplantation, even if the infection is brought under control. Severe loss of vision or of the eye may occur, even if the condition is diagnosed early and managed appropriately. Therapy and treatment are long, lasting as much as a year or more."

Plano Contact Lenses

"Plano (cosmetic) contact lenses are non-prescription contact lenses with colours and/or patterns on the surface. Like all contact lenses, these novelty lenses sit directly on the front surface of the eye and, as such, must be treated with the same degree of care as other lens types.
Under new regulations introduced in June 2005, plano cosmetic contact lenses are now regulated in the same way as powered lenses and may only be fitted by or under the supervision of a registered optometrist, qualified dispensing optician or medical practitioner.
Your contact lens practitioner will advise you on the most suitable lens type, wearing schedule, replacement frequency and care regime. Regular aftercare check-ups, at intervals specified by your practitioner, are essential to ensure that your eyes remain healthy and that you are using the best lenses for your particular needs."

Corneal Infections and Contact Lenses

"Acanthamoeba keratitis is a rare but very painful and potentially blinding infection of the cornea, the transparent covering at the front of the eye. The infection rate is approximately one in 30,000 contact lens wearers and in around 85% of cases the condition is associated with contact lens use.
The organism that causes the infection has been found in most environments including domestic tap water, chlorinated swimming pools, hot tubs and bottled water. It is also present in the nasal passages of healthy people.
Most research studies reporting this infection in contact lens wearers link it directly with poor patient hygiene, usually as a result of poor compliance with the practitioner’s instructions for lens care. Risk factors for infection in contact lens wearers are:

• Use of tap water during lens care (to rinse lenses or the storage case)
• Wearing lenses while swimming (without goggles), showering or in hot tubs
• Use of ineffective lens care solutions
• Failure to follow lens care instructions
  

Most cases of Acanthamoeba keratitis are preventable if contact lens wearers follow the instructions given to them by their contact lens practitioner. Contact lens wearers not complying with these instructions may be increasing their risk of infection with Acanthamoeba and other organisms. Switching solutions without the advice of your contact lens practitioner is not recommended.

Always seek professional advice if you are having problems with your contact lenses and have regular check-ups as specified by your practitioner. Symptoms of Acanthamoeba keratitis include the sensation of having something in the eye, watery eyes, blurred vision, sensitivity to light, swelling of the upper eyelid and extreme pain. However, if you experience these symptoms it does not necessarily mean you have Acanthamoeba keratitis.

Each time you wear your lenses you should check that your eyes look clear (no redness), feel comfortable and see well. If they do not, remove your lenses immediately and seek the advice of your contact lens practitioner. "

Orthokeratology

"Ortho-keratology, or Ortho-K, is the use of specially designed rigid gas-permeable (RGP) contact lenses to alter the shape of the cornea in order to reduce or correct myopia (short-sight). It can also be effective with low degrees of astigmatism.
According to the British Orthokeratology Society the procedure works best for people who are short sighted up to about –5D of myopia with no more than –1.50D of astigmatism.
To see if you fall within these categories look at your most recent spectacle prescription. If the ‘Sph’ box is –5.00 or less and the ‘Cyl’ box is –1.50 or less you may be suitable for orthokeratology and if you are interested we recommend that you consult your optometrist to discuss this procedure. Even if you are within these prescriptions, some people are more successful with orthokeratology than others.
If you are long sighted (up to +3 D) or more short sighted (up to –10D) you may be suitable for orthokeratology but this will be more complex than for the prescriptions above.
If you are over the age of about 45 and need bifocals/varifocals or a separate prescription for reading (or take your spectacles off to read) you must realise that if orthokeratology is done in both eyes this will affect your reading prescription too. If you are treated so you are not short sighted for distance and you would previously have removed your distance spectacles to read you will find that when your short sight is treated you will need to wear reading spectacles instead. You may find that this is more inconvenient than simply removing your spectacles to read. Your optometrist will advise you about this in more detail, and one of the advantages of orthokeratology is that it is reversible, so if you don’t like the effect you can return to the status quo"

Researchers test treatment for short-sighted kids.

"Researchers at the University of New South Wales are running a trial of special contact lenses that they hope will be able to correct short-sightedness in children.
The treatment, known as orthokeratology, is used widely in Asia.
Associate Professor Helen Swarbrick says there is compelling new evidence that the lenses can do more than simply correct short-sightedness.
'The excitement in this new research is that if we use these lenses in children we might be able to slow down or stop the short-sightedness,' she said.
Associate Professor Swarbrick explains how they are used.
'The lenses are worn overnight during sleep. During sleep they reshape the front of the eye,' she said.
'Then in the morning the patient can remove the lenses and see clearly all day without contact lenses.'
Unlike day time lenses, these are made of a hard plastic which shapes the cornea.
The treatment is widely used in Asia, where up to 85 per cent of people are myopic."

Guide to contact lenses; health and safety tips for contact lens wearers

"Contact Lens Safety Tips

Never lend to or swap your contact lenses with another person.
Do not sleep with contact lenses unless otherwise directed by your optometrist or contact lens practitioner. Wearing contact lenses overnight even for a short period comes with a greater health risk compared with nightly removal.

1. Do not wear your lenses longer than prescribed.
2. Never use saliva to clean your lenses.
3. Clean your lens case at least once a week and let it air-dry, or preferably replace lens case once a month.
Go for a complete eye examination every 24 months or more frequently if directed by your optometrist
Clean and disinfect your lenses every day.
4. Wash your hands with, preferably, a non-perfume soap before handling your lenses.
5. Don't wash your lenses in distilled water, tap water or non-sterile homemade saline.
6. Do not let your solutions bottle tip touch any surface, including your contact lenses, as it will become contaminated.
7. Use a solution recommended by your doctor. Not all solutions can be used for all contact lenses.
8. Use water based cosmetic formulations.
9. Insert lenses before applying eye makeup and take them out before removing the make-up again."

Alabama School Of Optometry Says Flu Sufferers Should Remove Contact Lenses.

"Birmingham, AL (AHN) - If you have the flu experts now say stick to your glasses and take your contact lenses out.
A professor at the University of Alabama at Birmingham School of Optometry say they aren't sure why viruses spread more easily in the winter, but they do know that eyes change and become drier when someone has a virus, so they advise against wearing contact lenses while you are sick.
'Many people don't realize that their eyes function differently when they're sick,' William 'Joe' Benjamin, Ph.D., professor of optometry at UAB said in a statement Wednesday. 'Tear production is altered, and eyes tend to get very dry. People may develop pink eye, conjunctivitis or other eye infections. The cornea can swell. Contacts can aggravate these symptoms.'
For those reasons, Benjamin advises against wearing contacts at times when someone is sick. But if they really can't avoid wearing your contacts, he has some tips to help do so as safely as possible.
Benjamin says it is beneficial to make sure to clean the contact lenses thoroughly and at least take them out periodically during the day to let eyes recuperate."

Study shows contact lenses can hurt eyes

"FORTY per cent of microbial corneal infections in Bahrain are due to misuse of contact lenses, according to a study by the Ministry of Health.
Other risk factors are as follows: 12 per cent dry eyes, 10 per cent blepharitis, eight per cent trauma, eight per cent lid malposition, two per cent corneal transplant and 20 per cent miscellaneous and unknown causes.
Physician Dr Nada Al Yousuf emphasised the role of contact lenses and its relation with this kind of infections. She noted that the mean age of contact lens wearer with keratitis was 21.
She stated that the majority of those cases were due to pseudomonas bacteria which is one on the dangerous microbes affecting the cornea. Moreover, 92 per cent of those cases have ended with permanent scarring to the cornea which loses the cornea its transparency and causes reduction of vision. One per cent of those infections were so severe that it required therapeutic corneal transplant.
Because of the visual morbidity associated with those infections and in view of the young age of such patients, using the proper instructions to prevent contact lens keratitis cannot be overemphasised.

"Sleeping with the contact lenses is one of the most important risk factors for microbial infection of the cornea. This is because while sleeping the corneal is deprived of oxygen which makes it more prone to infections," she said.

Moreover, Dr Al yousuf warned contact lens users not to bathe or swim with the lenses. This is because of the strong association between parasitic bacterial infections (Acanthamoeba) and contaminated water.

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