Appendix A

CONTACT LENSES ARE NOT RISK FREE

Cornea - Transparent, dome-shaped front surface of the eye which overlies the iris. It is analogous to a clear watch crystal that overlies the face and dials of a watch.

Reported Precautions and Dangers of Contact Lens Wear

Contact lenses are not risk free. It has been shown that the risk in contact lens wearers of sight-threatening corneal infection (ulcer; microbial keratitis) is very real. It has been reported that 25% of patients who present with microbial (ulcerative) keratitis (which can lead to permanent loss of eyesight) are contact lens wearers.

Irreversible and permanent corneal warpage, corneal distortion and endothelial damage are real and may occur after years of long-term use of contact lenses.

The annual risk for microbial keratitis (corneal ulceration and infection) is as follows:

1. Extended wear contact lenses: about 1 per 500, including disposable contact lenses.
2. Daily wear soft contact lenses and hard gas permeable contact lenses: 1 per 2500.
3. Daily wear non-gas permeable hard contact lenses: 1 per 5000.

Pseudomonas Keratitis associated with contact lens wear is one of the most dangerous organisms that can threaten the integrity of the cornea. If not diagnosed immediately and treated aggressively, it can literally ulcerate and melt through the full thickness cornea in a matter of hours, and can potentially blind the eye or cause permanent loss of vision from corneal scar, which would necessitate corneal transplant. These organisms live very easily in a number of lens solutions, lens cases, oily places, etc.

Little corneal infiltrates with small overlying epithelial erosions in a contact lens wearer are potentially very serious and could lead to permanent vision loss if not treated promptly and aggressively. Therefore, it has to be assumed that the cornea is infected and treated as an ocular emergency until appropriate lab studies come back.

It is therefore obvious that one must use impeccable hygiene in the care and handling of contact lenses.

Pseudomonas Keratitis accounts for 1/3 to 3/4 of the organisms seen in contact lens-associated microbial keratitis. Approximately 25% are due to gram positive cocci such as staph., strep., etc.
 

Contact Lens Associated Problems:

1. GPC (Giant Papillary Conjunctivitis)
2. Contact lens related SLK (Superior Limbic Keratoconjunctivitis) or contact lens induced keratoconjunctivitis (CLIK)
3. Chronic corneal edema (swelling)
4. Dry Eye
5. Neovascularization of the cornea
6. Contact lens, lens case, and contact lens solution contaminants.

• Chronic eye discomfort such as stinging and burning
• Eye lid swelling
• Decrease contact lens wear time
• Redness
• Foreign body sensation

1. GPC (Giant Papillary Conjunctivitis) from contact lens wear
One develops multiple tiny, inflammed bumps on the inner side of the upper lid, which can be very irritating to the eyes. This can be caused from protein buildup and accumulation on the surface of the contact lens and/or mechanical rubbing of the contact lens on the inner surface of the upper eyelids as one blinks.

Treatment:

1. Enzyme cleaning of contact lens to remove accumulated protein deposits.
2. Addition of antiinflammatory drops to subdue the inflammation.
3. Exchange of contact lenses for new ones or different brand.
4. The above methods of treatment may not result in complete disappearance of these inflammed inner lid bumps, but may decrease the symptoms somewhat.
5. Frequently, the only way to truly cure GPC is to discontinue contact lens wear completely. It may take several weeks to months for these bumps to disappear, and occasionally they leave small inner eyelid scars which are of little or no consequence but can be observed under the microscope (slit lamp) after lid eversion several months later by the examining doctor.

Treatment:

1. Enzyme cleaning of contact lenses
2. Addition of antiinflammatory drops to subdue the inflammation.
3. Exchange contact lenses
4. 1% silver nitrate swab applications to the "bulbar conjunctiva"
5. Surgery to remove this thickened tissue.
6. May have to discontinue contact lenses all together and can take 6 months or longer before the cornea smooths down.
7. Discontinuance of the use of solution with thimerisol should help, if the wearer has used a contact lens cleaning solution containing thimerisol.

The main concern with contact lens hypoxic keratopathy is that repeat bouts of persistent corneal hypoxia may eventually lead to permanent corneal damage with clinically significant endothelial cell dysfunction. The endothelium is a mosaic of cells that line the entire area of the inside of the cornea and are responsible for maintaining corneal transparency. If they are significantly compromised, then corneal decompensation can take place, the cornea can become opaque and one can experience significant reduction in vision, possibly on a permanent basis. This also predisposes the eye to a greater chance for microbial infection.

Treatment:

Exchange contact lenses for better fit and contacts that allow high Oxygen permeability. If this does not solve the problem, it is best to discontinue contact lens wear.

4. Dry Eye associated with contact lens wear
If one has a "dry eye", it is often difficult to wear contact lenses for long periods of time. Artificial tears without preservative are recommended. Some individuals who desire to wear contact lenses but have even a borderline dry eye situation have difficulty with comfort and clear vision with contact lenses.

5. Neovascularization of the Cornea in association with contact lenses
Superficial and sometimes deep blood vessels can abnormally grow onto the cornea from long-term use contact lenses. Only the examining doctor can see them under the microscope on examination. They grow because of mechanical rubbing and poor oxygenation by the contact lenses. It is undesirable for this to occur. If they proliferate to such a degree that they encroach on the visual axis area, they would cause a decrease in vision, glare, corneal distortion, corneal melt problems, etc.

6. Contact lens, lens case and contact lens solution contaminants
Discomfort and decreased wearing time can result from contact lens, lens solutions, and lens case contaminants.

Some of these contaminants are as follows:

• Residual cleaning enzyme accumulation
• Cleaning solution and enzyme residues
• Contamination with bacteria and fungi, which potentially can lead to risk of serious corneal infection.

Acanthomoeba is another extremely dangerous microorganism involved in contaminating contact lenses and cases, especially when using the "home made" saline and using tap water or well water to clean contact lenses. Acanthomoeba is very difficult to treat and cure. Some patients with this type of keratitis have to be treated for months to years with a poor prognosis for recovery of sight, in spite of corneal transplantation if it were to become necessary.

7. Contact lenses may cause permanent or irreverisble warpage of the cornea, which could induce permanent astigmatism.

Conclusion:

Economic Considerations:

A contact lens wearer may pay between $250 and $500 per year on proper contact lens care, and a lifetime expenditure may be $10,000 to $15,000 or more. Refractive surgery may be safer and less expensive than contact lens wear in the long run.

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