To See or Not to See:
A Swimmer's Dilemma

BY JANICE JURKUS, O.D., M.B.A., & MICHAEL A COLARUSSO, O.D.
MAR. 1996

There are millions of water sports enthusiasts around the world, and whether they compete seriously or just swim for fun, good vision is vital for safe and successful participation.When our contact lens patients are involved in water sports, we're faced with a delicate dilemma. Should we allow them the benefits of good vision and increased safety they would gain by wearing soft contact lenses during water sports? Or should we oppose this, in accordance with the FDA's and manufacturers' guidelines, to minimize the risk of infection? We must recognize and address these conflicts especially if we provide eye care to patients who swim.

CONSIDER INTERACTION WITH THE WATER

Surfing, water skiing, scuba diving, sailing, windsurfing, swimming and diving all involve environmental interactions with the water, including impact with the water, spontaneous submersion, wind and spray. There are also specific water interactions unique to each sport. For example, water skiing is a high velocity sport creating a forceful wind that blows directly into the skier's face. There is also potential for high speed impact with the water if the skier falls, and the skier needs to see hazardous obstacles in the water as well as signals from those on the boat.

Surfing requires good vision to see waves and to avoid hitting other surfers or swimmers when riding a wave. Without good distance vision, surfers may injure themselves or others when emerging from the water, or they may become disoriented and unable to distinguish landmarks on shore.

Ocean diving decreases stereoscopic vision because less light reaches the eyes causing objects to become less distinct. Divers can minimize this problem by wearing a soft lens correction and a plano mask. This approach also helps overcome troublesome fogging and removal of a prescription mask.

FEWER INJURIES, BETTER PERFORMANCE

Swimming and diving in pools also pose challenges to the ametropic water lover. Slight distance miscalculations by a diver can result in injuries such as lacerated heels. With a soft contact lens correction, an ametropic swimmer or diver can improve depth perception and awareness of position and direction. These reflexive movements require accurate visual information in a constantly changing environment. Divers who wear contact lenses say their performances improve.

EFFECTS OF WATER TONICITY

The behavior of soft contact lenses in an aquatic environment depends largely on the tonicity of the water. As tonicity varies, the lens dimensions change due to equilibration. The overall diameter of a soft lens increases in a hypotonic environment such as a fresh water lake; the lens fits tighter and adherence occurs. In the hypertonic environment of the ocean, the lens fits looser.

Diefenbach et al. determined that only four to six drops of pool water (80 mOsm/kg) caused zero lens movement and corneal adherence. Stein and Slatt determined that adherence occurred within three to four minutes in pool water.

Higher water content soft lenses absorb and retain swimming pool water and its toxic compounds, according to Soni et al. They also found that 100 percent of the soft lenses worn while swimming in a pool were contaminated to some degree. Other authors reported no clinically significant amounts of organisms or chemicals after lab analyses of soft lenses worn in pools or oceans.

Soft lenses worn in the ocean actually "float" on the cornea, rather than adhere to it. Few soft lenses are lost while swimming in either hypotonic or hypertonic environments because the edges of these large-diameter lenses tuck under the superior and inferior lid margins.

BACTERIAL INFECTIONS

The risk of bacterial infection is a serious concern when patients swim while wearing their soft contact lenses. Microbes are present in all aquatic environments. Pool water periodically shows low counts of staphylococci, streptococci, pseudomonas aeruginosa and acanthamoeba. Pseudomonas and acanthamoeba cause the most serious cases of microbial keratitis in contact lens wearers. When they detect pseudomonas in public pools, health authorities usually "shock treat" the pools with additional chlorine which may bind to the polymer of hydrogel soft lenses causing an allergic or delayed response, according to Hoelting et al.

Chemicals in oceans and lakes are also cause for concern. Soft lens wearers who surf in the ocean after heavy rains may be exposed to untreated sewage and road oils, for example. Despite the presence of organisms and chemicals in the water, studies have shown there are no clinically significant amounts of chemicals or microbes within soft lenses after the wearer swims.

THE SOFT LENS SHIELD

In pools or lakes, the cornea imbibes water from the contact lens. Several authors have concluded that a hydrogel soft contact lens functions as a "protective shield" against the effects of chlorine thus reducing risk of "chlorine burn," a condition that can damage epithelial cells and cause corneal edema. After swimming with a soft lens on, research subjects showed no decrease in visual acuity, no slit lamp abnormalities on the cornea, nor any aftereffects when the lenses were removed. Solomon found that contact lenses decreased halo size and corneal swelling in swimmers. They also reduced corneal staining caused by chlorinated water and caused no appreciable change in keratometry readings. In addition, contact lenses reduced conjunctival hyperemia. The conjunctiva showed hyperemia only beyond the edges of the lens, remaining relatively protected between the limbus and the lens edge. The cornea does not appear to suffer any damage from swimming with soft lenses on as long as the epithelial cell layer remains intact.

By identifying patients who swim with their lenses on and instructing them on post-swim lens care, you can provide valuable information so that they can make an educated decision. CLS

INSTRUCTIONS FOR PATIENTS WHO WEAR CONTACT LENSES WHILE SWIMMING:

There is a risk of developing a corneal infection if you wear soft contact lenses while swimming. If you decide to take that risk:

1. Carry spectacles in case lenses are lost.

2. Use saline to rinse eyes after swimming.

3. Close eyes under water.

4. Use fast blinks to clear water from eyes. Do not rub.

5. Wait at least 20 minutes before attempting lens removal. Use rewetting drops or saline to make lens removal easier.

6. Carefully clean and disinfect lenses or replace them after each swim.

IF YOU HAVE PATIENTS WHO WEAR CONTACT LENSES WHILE SWIMMING:

1. Obtain informed consent, and advise patients that they assume all risk of loss of their lenses.

2. Encourage patients to use goggles over soft lenses.

3. Explain how instilling distilled water or splashing pool water in eyes prior to swimming or diving promotes adherence and decreases the chance of lens loss.

4. Advise patients to squint or keep eyes partially closed if submersion is imminent, to keep eyes closed under water, and to use fast blinks instead of rubbing to clear water from eyes.

5. Instruct patients to wait at least 20 minutes after swimming before removing lenses to allow equilibration with tears. This allows the lenses to loosen and prevents denuding of the corneal epithelium.

6. Tell patients to use normal saline to irrigate their eyes and loosen lenses for removal as well as flush out microbes and chemicals.

7. Ensure that patients can reinsert their lenses without a mirror.

8. To minimize risk of infection, advise patients to have at least two sets of lenses so that the pair used for swimming can be cleaned and disinfected immediately, allowing the patient to put in a fresh pair.

9. Prescribe disposable lenses so patients can simply throw them away after swimming.

10. Emphasize that if the eyes become irritated, if vision is fuzzy, or if any pain occurs, patients should remove lenses carefully and contact you immediately.

References are available upon written request to Contact Lens Spectrum; to receive references via fax, call 1-800-239-4684 and enter Document #11. (Be sure to have a fax number ready.)

Dr. Jurkus is an associate professor at Illinois College of Optometry in Chicago, and she is chairperson of the Association of Optometric Contact Lens Educators. Dr. Colarusso is a 1995 ICU graduate and an expert surfer.