A: There are several reasons: (1) Because of the aforementioned blepharoptosis, (2) because an abrasion may occur, and (3) because of the possible introduction of bacteria, fungi, or viruses.

Q: How many hours a day can I expect to wear contact lenses?

A: That depends upon the lens and your eyes. Most people are eventually able to wear their lenses most of their waking hours: about eight hours for hard-lens wearers and fourteen hours for soft-lens wearers. But every pair of eyes is unique. Some people can wear their lenses for only four hours a day; some can go for as long as eighteen hours, though this is not a good idea unless you break up the time with a rest period. This method can be used by anyone to effectively extend wearing time: Remove your lenses and let the eyes rest for fifteen or twenty minutes. This gives them a new lease on life, and lets you wear your lenses late at night after a long day at the office.

Q: But what if I want to wear contacts just for special occasions?

A: This can only be done if you wear soft lenses or gas-permeable lenses. Once you’ve adapted to hard lenses, you should wear them every day for the same number of hours. Otherwise the eye will “unadapt” and the lenses will become uncomfortable. Soft and gas-permeable lenses are less demanding where adaptation is concerned, and you can safely and comfortably wear them intermittently—for the weekend softball game, your triweekly jog, or just for social events.

Q: Is there an age barrier in contact lens wear?

A: Theoretically speaking, no. I have fitted infants and ninetyyear-olds with contact lenses, and every age in between. One of my patients is in her seventies and has been wearing contact lenses . . . a true pioneer! Infants wear contact lenses not out of vanity, but for therapeutic visual reasons.

Teen-agers adapt to contact lenses very quickly, a testimony to the importance of motivation and the role that improved appearance plays in successful contact lens wear. Puberty may herald marked changes in refractive errors; therefore these youngsters should be examined at least twice a year.

Though contact lenses can be worn at any age, eager parents should wait until a child is ready to use them. The child should be motivated, versed in hygiene, mature enough to accept the responsibility for caring for the lenses, and have the necessary motor skills for handling these tiny, delicate lenses. This usually occurs around the age of twelve. In certain cases parents may be taught to insert and remove the lenses for those too young to have the manual dexterity to do so themselves.

Q: If my prescription seems to change frequently, can I still wear contact lenses? Won’t it be more expensive than changing the prescription of my eyeglasses?

A: Unless a medical contraindication exists, there is no reason you cannot wear contact lenses—even if the prescription changes frequently. The cost of the new contact lenses usually is comparable to that of new spectacle lenses. In fact changes of spectacles may prove to be the more expensive of the two.

Q: Is there some magic formula for being able to wear contact lenses successfully?

A: Yes, in a way. And there are three ingredients:

1. The eye practitioner. Select an expert eye practitioner who specializes in contact lenses. An ophthalmologist or optometrist in private practice is your best choice. With proper medical care, you’ll be most likely to wear your contact lenses comfortably and without damaging your eyes. Don’t forget: you get what you pay for. Unfortunately there are a multitude of unhappy contact lens wearers who bought “bargain lenses” and then discovered that they were no bargain at all.

2. Motivation. Depending upon the type of lens and your own unique physiology, contact lens wear brings some initial discomfort. You must be sufficiently motivated to tolerate this initial adaptation period, as well as any little difficulties that may crop up later.

3. Follow instructions! Many unsuccessful contact lens wearers simply didn’t take care of their lenses and eyes properly. The result is reduced lens life, wearing discomfort, poor vision, and possible eye injury.

Q: Can contact lenses harm the eye?

A: Contact lenses are dangerous if you have a faulty lens, or do not maintain proper ocular hygiene, or don’t follow the recommended wearing and handling procedures. For instance, corneal abrasion can occur when the lens isn’t inserted properly. Corneal edema occurs if you overwear the lens. An eye infection may be caused by fingers or contact lens solutions that are contaminated. And foreign bodies can sneak under the lens and irritate the cornea.

With regard to the vast number of contact lens wearers, though, such complications have been remarkably rare.

Q: What is corneal edema?

A: It is the most common contact lens complication and the main reason you can’t wear lenses for twenty-four hours (except for extended-wear contacts). Edema means swelling, which is what happens to your cornea when you wear your lenses too long and deprive the cornea of oxygen. Even though gas-permeable lenses, soft lenses, and lenses that allow optimum tear exchange reduce the chance of edema, there is always less oxygen than normally reaches the naked eye. You’ll know when you’ve been wearing your contacts too long: your eyes will burn, turn red, be light sensitive; maybe you’ll see halos or rainbows around lights. Unless you’re too stubborn or highly motivated, the most appealing thought in the world will be that of removing your lenses, which is exactly the right thing to do. In minor cases your cornea will recuperate in a few hours (better yet—overnight). If you really overdo it, recovery may take several days and corneal abrasion may follow.

Q: What is conjunctivitis?

A: This is an infection of the conjunctiva, the mucous membrane that covers the white part of the eye and lines the underside of the eyelids. Conjunctivitis and other eye infections can afflict the contact lens wearer who doesn’t clean (and disinfect, in the case of soft lenses) his lenses according to instructions. It can also occur when wearers clean and wet the lenses with saliva, which is loaded with bacteria, viruses, and perhaps fungi. In addition to the ordinary garden-variety conjunctivitis (”pink eye“), there’s another form called “giant papillary conjunctivitis,” which is caused only by contact lens wear (the contact lenses themselves, deposits on the lenses, or any of the contact lens solutions). In treating the individual with this type of conjunctivitis I discard the contact lens and prescribe a steroid (cortisone) eye drop. Resolution of the disorder may take days or even weeks. Once the conjunctiva has healed, I order a new lens and then instruct the patient to use different solutions. For the hard contact lens wearer the correct solution is determined by trial and error. For the soft contact lens wearer I permit only the use of unpreserved saline and the heat method of disinfection. Happily, this type of conjunctivitis, when treated properly, rarely recurs. If it does reappear, cessation of contact lens use may be the only solution.

Q: What’s corneal abrasion?

A: Corneal abrasion is the term used when the surface layer of the cornea is scraped or scratched off. This can occur when you wear the contact lenses too long (overwear syndrome); with improperly fitted lenses; or by inserting, removing, or recentering the lens improperly. Sleeping with daily-wear lenses on often leads to corneal abrasion. The symptoms are decreased vision, burning pain, sensitivity to light, the sensation of having something in your eye, and copious tearing. Abrasion that follows corneal edema may not be evident until hours after the contact lenses have been removed. Healing is mercifully rapid: usually within thirty-six hours. You may take aspirin for the pain, and cold compresses may help. Consult your ophthalmologist to make sure there are no complications; he may also recommend that you wear a tight eye patch for the duration of the recuperative period to keep the eye immobile. Though most cases of corneal abrasion are minor, a severe infection can invade the damaged cells. While this is unlikely to occur, it is a possibility, so don’t treat corneal abrasions lightly.

Q: Can contact lenses cause drooping of the eyelids?

A: It’s rare, but the results of one study indicate that in a very few cases, contact lens wear can lead to a condition called blepharoptosis, resulting in eyelids that appear to droop. All the patients studied had been wearing hard lenses, some for many years. The researchers’ most likely explanation is that the condition was caused by excessive manipulation and rubbing of the eyelids, usually because of difficulties in inserting and removing the lenses. The trauma caused eyelid muscle damage. This condition can be corrected surgically.

Q: Can the eye become dependent on contact lenses?

A: No. Wearing contact lenses neither improves nor worsens vision. The only “dependence” is a psychological one. The excellent vision correction provided, the convenience, and the improvement of one’s appearance make many wearers contact lens “addicts.”

Q: Why is my vision blurry while wearing eyeglasses after I remove my contact lenses?

A: This condition is called spectacle blur. It usually occurs with hard lenses and is due to corneal molding. The cornea is pliable and its shape is changed slightly by the contact lens, much as the skin of your finger becomes indented by a ring. Just as the indentation on your finger disappears after the ring is removed, your cornea gradually assumes its original shape. In the meantime you have an irregularly curved cornea causing a kind of “induced astigmatism,” for which your spectacles were not ground to correct. As a result of this temporary and artificial refractive error your vision is slightly blurry when you switch to spectacles. This situation may last from a few minutes to a few hours.

Q: Why do I see differently when I switch back to glasses?

A: See discussion of spectacle blur. Also this difference in vision may be due to the fact that spectacles for nearsightedness reduce the size of objects and those for farsightedness magnify objects (especially for aphakics, who are very farsighted). With contact lenses there is no such effect. When you switch from contacts to glasses, your brain becomes momentarily confused and interprets the smaller or larger image as blurry. Again this phenomenon is fleeting and only mildly annoying if you wear contacts most of your waking hours. Should you decide to return to full-time spectacle wear, your brain will adapt to this different way of seeing in a short period of time.

Q: Why can’t I use saliva to clean contact lenses?

A: Though the composition of saliva makes it a very efficacious wetting solution for hard lenses, it is absolutely unacceptable to use it for this purpose. Saliva contains bacteria (and possibly viruses and fungi) that are safe for the mouth, but dangerous for the eye.

Q: Can I use hard contact lens solutions for soft lenses and vice versa?

A: Absolutely not. These solutions were designed for specific types of plastic. Because hard lenses and soft lenses have very different properties, their accompanying solutions contain different ingredients. In addition soft lenses will absorb the chemicals in the hard-lens solutions; these chemicals can later be released into the eye, possibly causing irritation or ocular damage.

Q: Can contact lenses be used in sports?

A: The bony structure (orbit) that forms the eye socket was designed to protect you from injury, and it does its job extremely well. But if you’re very active in sports, for instance, hard lenses may pose problems. If you are hit directly in the eye with a racquet ball, wearing a hard contact might result in greater ocular injury than if you were not wearing lenses. That a contact lens would shatter, however, is highly unlikely: the plastic from which it is made requires the force of a hammer striking it on a cement surface in order to break it. Of course, soft lenses are safer. In some instances a contact lens can actually act as a barrier and shield the eye from scratches. However, for contact sports and racquet sports you should wear special protective glasses, goggles, or masks, whether you wear contact lenses or not.

The lens functions basically as a protective shield and prevents a damaged or ailing cornea from coming into contact with the eyelids and the air. Healing is thereby accelerated and pain is alleviated for as long as the lens is worn, which is on an extended basis (more than twenty-four hours). As such it can take the place of the tight eyepatch formerly used to immobilize the eye to facilitate the recovery process. It is usually needed only temporarily until the condition being treated has cleared up. The lens is placed on the cornea by the ophthalmologist and is removed by the doctor when the disorder being treated has been cured.

Uses of Bandage Lenses

The lens has been used for many years with varying degrees of success to treat a great number of conditions. The most frequent uses are for:

Dry Eyes. Although I have cautioned against the use of a soft lens when tear production is reduced, this lens plays an important role in severe cases of dry eyes. The dry-eye syndrome is a common by-product of the aging process and affects women more often than men. In postmenopausal women all the mucous membranes begin to dry because of the shift in hormone production. In these cases dryness of the eye can become quite severe. A dry eye may also be caused by drugs (birth control pills, antihistamines, and so on), injury to or infection of the lachrymal glands, autoimmune disorders (Stevens-Johnson syndrome), severe injuries or infections of the eye, and vitamin deficiencies.

Eyes with a marked reduction in tear production can lead to damaged corneas. For patients suffering from dry eyes a bandage lens in tandem with frequent instillation of artificial tears is an excellent treatment. The eye drops are absorbed by the highly hydrophilic (water-loving) lens, bathing the eye with them in a more constant fashion than if drops alone were used.

Bullous Keratopathy. As a result of the aging process or following injury to the eye, which may be accidental or occur after intraocular surgery such as cataract extraction, the cornea may swell with an abnormal amount of fluid. The inner surface of the cornea (endothelium) becomes damaged, vision becomes blurred, and there is marked pain. The bandage lens can reduce and sometimes completely alleviate both symptoms by protecting the eroded corneal surface and by acting as a barrier to prevent fluid from escaping from the cornea.

Corneal Ulcers and Abrasions. The bandage lens seems to accelerate the healing process in abrasions and ulcers that can result from viral, bacterial, and fungal infections. This form of treatment should only be used in conjunction with antibiotic, antiviral, or antifungal eye drops.

Trichiasis. As a result of an injury, infection, or aging, the eyelashes may turn inward and rub against the cornea. A bandage lens can act as a shield while (or until) the primary condition is treated.

Chemical and Thermal Burns. By eliminating the constant irritation of the eyelid coming into contact with the healing corneal tissue, a bandage lens allows the cornea to grow back normally and more rapidly. Using a bandage lens postoperatively after a burn increases the success rate of such surgery.

Penetrating Corneal Wounds. When the cornea becomes wounded, a bandage lens aids in forming a protective shield and can be employed to facilitate healing when surgery has to be delayed.

Bell’s Palsy. When the upper lid is unable to close completely, the cornea may become overly dry. The bandage lens protects the cornea, but frequent instillation of artificial tears is necessary as an adjunct.

The “Contact Lens” as a Drug Deliver System

There now exist tiny discs containing special medication that may be placed on the eye to provide a constant source of medication. The small oval-shaped flexible “lens” is worn over the sclera under the eyelid. Its sole purpose is to act as a reservoir for drugs in liquid form, allowing specific amounts to be released into the eye gradually over a prolonged period of time. It’s really a time-release capsule for the eyes. The drug in use is, therefore, more effective than when it is administered as intermittent drops, because constant, round-the-clock treatment is possible. Also lesser amounts of the drug may do the job with this method. This can in turn reduce the local and systemic side effects and allow the use of more potent drugs such as steroids and glaucoma medication. Once in place the “contact lens” is a convenient way of administering medication, particularly for patients who might not otherwise comply with the prescribed treatment. Ocusert, containing the glaucoma medication pilocarpine, and Lacrisert, containing lubricating medication, are the two special “lenses” now commercially available. They can be worn continuously (even while sleeping) and removed and replaced weekly for the duration of the treatment.

This type of lens has been put to artistic use in the movies by actors creating bizarre special effects, such as the eyes of monsters. Ironically prosthetic lenses can also be of real help to those who need something special in order to appear normal. They can dramatically improve the appearance (and sometimes the vision as well) of eyes that have been disfigured or in some way appear abnormal. This includes those who suffer from albinism or unsightly, deformed eyes whose defect is congenital in origin or due to accidental injury or a result of eye surgery. The ultimate type of prosthetic contact lens is the one that forms the “false eye“—or shell over the entire socket when an eye is enucleated (surgically removed).

Prosthetic contact lenses, which may cover the entire sclera or only the cornea, are predominantly manufactured in rigid form, though soft prosthetic lenses are available. The lenses simulate a normal iris and pupil by incorporating an opaque area that is colored artistically to achieve the final appearance of the eye. The desired image may be placed on any portion of the lens, and may be of any color. It is stable and nontoxic because in one type the image is “painted” on the surface of one lens and then covered with another lens, forming a “sandwich.” Another method employs a special tinting process of a soft lens.

CosmeticContact Lenses

For those who wish to change the color of their eyes, especially actors or models, the cosmetic contact lens is a real boon. Some of these lenses cover only the cornea, are made of rigid PMMA material, and are opaque, except in the transparent central area. This clear zone covers the pupil and may have a prescription incorporated. Obviously the lens has to center perfectly. Fitting is difficult and may require many sessions. Care and handling is similar to the standard hard lens. Soft lenses may also be tinted to provide similar cosmetic results.

The poor vision brought on by keratoconus is due to a highly exaggerated form of astigmatism that is poorly corrected by glasses. Until contact lenses became available, keratoconus patients often had to be satisfied with partially corrected vision and led less-than-normal lives. But contact lenses can provide almost perfect vision in most cases and are the best means of vision correction for this disorder.

Hard contact lenses are usually used because the smooth, dome-shaped shell plus the tears beneath it provide a new smooth, round refracting surface for the eye. Because the cornea is diseased, the eye may not tolerate conventional hard lenses. In that case gas-permeable contact lenses may be prescribed instead. Soft contact lenses, in general, do not work well with keratoconic eyes. As is the case with astigmatism, the pliable material from which they are made conforms to the misshapen cornea, duplicating the refractive error. Soft contact lenses may, however, correct a portion of the faulty vision. And in some cases the patient is fitted with hard lenses on top of the soft lenses, piggyback fashion, to take advantage of the comfort of the soft lens plus the sharp visual acuity provided by the hard lens. In all cases the lenses are difficult to manufacture, and the fitting process must be extremely exact to achieve acceptable results.

Eye practitioners can test you if you suspect you are color deficient. Telltale signs include a lack of interest in colors, choosing color combinations that don’t appeal to most people, a preference toward blues and yellows and indifference toward reds and greens, unawareness of fall foliage, difficulty in seeing veins and freckles, and the preference of black-andwhite TV over color.

In the past there was nothing available to improve color blindness. But several years ago Dr. Harry Zeltzer developed a special, red-tinted contact lens that improves the color perception of those who suffer the most common type of color blindness (red-green). (A red-tinted lens in eyeglasses doesn’t work because the lens is too far away from the eye.) The X-Chrom lens has been a godsend to people whose jobs and interests require the ability to identify colors. Telephone repairmen, hunters, drivers, home handymen, painters, cosmeticians, printers, textile workers, chemists, photographers, artists, decorators, and anyone who selects clothes (even if it’s just their own)—all can benefit from this type of lens. It has even helped color-deficient children who were wrongly labeled as learning deficient.

The X-Chrom lens is deep red in color. Only one tinted lens is prescribed, usually for the nondominant eye. It works by changing the relative intensities of red and green objects. The nondominant (corrected) eye supplies the brain with information about colors that are normally hard for it to identify; the dominant (uncorrected) eye continues to supply the colors the eye is capable of seeing correctly. As if by magic the wearer sees colors he never even knew existed. At first colors may seem to glow or be more vibrant, and objects that used to blend into the background may seem to jump out. But the eye and brain soon adjust to the unfamiliar information: the newly perceived colors are identified and learned.

If necessary the X-Chrom lens can be manufactured to incorporate a prescription to correct refractive errors. In that case the wearer keeps his regular clear lens in the dominant eye and the X-Chrom corrective lens in the other. Usually a third, clear contact lens incorporating the necessary prescription is kept on hand for use in the nondominant eye when the X-Chrom is not worn. Those who do not wish to wear a contact lens in both eyes can wear glasses over the X-Chrom lens.

The fitting, adjustment period, wearing, care, and handling of the lens are the same as for conventional hard lenses, but the cost is higher. The X-Chrom may be worn during both daytime and nighttime, but many elect to remove the lens at night because of the reduced illumination that will be exaggerated with this lens. Some wearers experience a slight reduction in visual acuity, or their depth perception is affected because the two eyes receive unequal amounts of illumination. Cosmetically the red color of the X-Chrom lens is very obvious. All these disadvantages must be weighed against enhanced color perception. The color-blind patient, therefore, has to be well motivated in order to wear this lens.

Clearly the X-Chrom offers no guarantees and is not for every color-deficient patient. In the words of its developer it’s “an aid, not a cure.” But for most color-blind people it means improved color perception and opens up new vistas in everyday pleasures and work.

Monovision Contact Lenses

In spite of these innovations bifocal contact lenses and their variations are obviously far from perfected. For those who can’t be fitted, or who fail to adjust to bifocal lenses, there are a few alternatives and compromises. A very popular one and one that is extensively employed is the “monovision technique.” One eye is fitted for distance (usually the dominant eye); the other is fitted for reading. Either hard or soft contact lenses may be used, and this is by far the best technique found to date: The success rate is estimated at between 70 and 80 percent. As in the past, when monocles were worn, the eyes and brain somehow manage to make sense out of what seems to be visual schizophrenia. Visual fusion and depth perception can still be obtained, and after a while the wearer forgets which eye has been corrected for distance and which for near. Though depth perception is usually adequate for normal wear, it is advised that a lens for distance be substituted for the reading lens during activities where depth perception is particularly important, such as driving or sports. With the monovision technique I have fitted many patients who are ecstatic about the fact that no glasses at all need to be worn.

Compromise Contact Lenses

This method has two variations. One is to change the contact lens prescription for farsighted people so that both lenses are slightly stronger than needed for distance vision and slightly weaker than would be required for reading. Thus adequate— but not perfect—vision can be obtained at all distances. The second method is to undercorrect the contact lens prescription for the nearsighted person so that both lenses are slightly weaker than necessary for distance and slightly weaker than needed for reading. Again adequate, but not perfectly sharp, vision is obtainable for those patients who are ready to accept this compromise.

As with the monovision technique the compromise technique may result in a small percentage of eyestrain or headaches. No permanent ocular damage can result; however, if the symptoms persist, this method should be discontinued.

Two Pairs of Contact Lenses

This approach is useful for public speakers and others who require the ability to see close up while in the limelight. Having two pairs of contact lenses—one pair for distance vision and one pair for near—works well if you have the time and patience to switch from one set of lenses to the other.

Glasses plus Contact Lenses

Of course there is always the option, whenever necessary, of wearing reading glasses for near vision over the distance-correcting contacts. This is still an improvement over wearing glasses for both refractive problems.

The presbyope has “trombone vision“—that telltale gesture of moving objects farther and farther away from the eyes in order to see them clearly. Most people opt for bifocal glasses or simply resign themselves to placing on a separate pair of glasses to read, sew, and do other tasks that require good close-up vision. However, there are several ways to correct this condition with contact lenses: bifocal contact lenses, “monovision” lenses, “compromise” contact lenses, having two pairs of contact lenses, and wearing reading glasses over contact lenses.

Bifocal Contact Lenses

Currently in the U.S. bifocal contact lenses are available in two types: conventional hard lenses and the newly released soft lenses. There are available basically two designs of either form of bifocal contact lens. Both of these, like spectacles, have two distinct powers, or prescriptions: one for near, one for far.

Crescent bifocal contact lenses most resemble bifocal eye-glasses. They have the prescription for distance at the top part of the lens, and the crescent-shaped segment at the bottom contains the prescription for close-up vision. As you gaze ahead normally, the distance power is used; as you gaze down, the near power goes into effect.

Because contact lenses naturally rotate on the eye during wear, some means of keeping bifocal lenses stabilized is necessary. Otherwise the crescent at the bottom would gradually drift toward the top where it would do no good—unless you held your newspaper over your head. These lenses are often weighted at the bottom with a thicker segment (prism), which utilizes gravity to keep the lens oriented. Crescent bifocals may also be truncated, a process in which the bottom edge is cut off to align it parallel with the lower eyelid margin. Another less effective modification that stabilizes bifocal lenses features orientation grooves cut into the top edge of the lens, providing a pathway for the inner surface of the upper lid to prevent rotation of the lens.

Like crescent lenses, concentric bifocal contact lenses also have two distinct powers, or prescriptions, but with a structural difference: the near prescription segment is in the shape of a ring acting as the outer rim of the lens; the distance power is a circle in the middle. With this lens, which resembles a bull’s-eye target, there’s no worry about its rotating on the eye. As with crescent bifocal lenses distant vision is effected by looking through the center, and near vision by looking down through the outer rim.

The best candidates for bifocal contact lenses are those who have been successfully wearing single-vision contacts for some time to correct myopia, hyperopia, or astigmatism. They will have the least problem with adjusting; but even so the success rate is low. The recent advent of the soft bifocal lens, however, should improve these statistics for the millions of presbyopes in this country, many of whom would no doubt be delighted to be able to wear bifocal contacts.

Fitting bifocal contact lenses is difficult (such factors as pupil size and lower lid position complicate the fitting process); manufacture of the lenses is more intricate than for the single-vision contacts; delivery time is slow; and the cost is necessarily higher than for conventional lenses. Many wearers report that bifocals are less comfortable than single-vision contacts, usually because the prism that prevents rotation adds bulk and makes the lens heavier.

New contact lens wearers not only have to adjust to lens wear in general but also have to adjust to the means of wearing a bifocal prescription. As in bifocal spectacles this involves learning how to adjust to the “jump” in vision that occurs every time you shift your gaze from near to far, or vice versa. Initially vision may be frustratingly poor —especially with hard lenses—during the adaptation period because the sensation of having a foreign body in the eye causes ocular physiological changes that lift the lower lid and the lens. Thus the bifocal segment is higher than it should be. Since this bifocal segment is so very small, there is very little tolerance in the proper positioning of the lens. As difficult as it is to achieve, perfect centering of the contact lenses is absolutely crucial for successful bifocal hard contact lens wear.

In response to these problems manufacturers are experimenting with design modifications. Multifocal or variable- focus contacts (available in hard and gas-permeable lenses) have not two, but many powers that gradually blend into each other, avoiding the annoying jump in vision. The lens contains all the different powers needed by the wearer to see clearly at any distance: near, far, and intermediate. The bifocal contact lens candidate will have to be patient and well motivated because it usually takes a few weeks until the lenses can be worn with comfort and provide good vision. Also some lens modifications and adjustments are usually the rule.

Until recently, therefore, patients had two contact lens options: to either wear a hard lens and get sharp vision, or wear a conventional soft lens and live with less-than-perfect vision. Now there is a new type of soft contact lens, the toric lens, which give astigmatics a third choice. While it is still in the early stages of use and development, this lens will eventually be perfected, and will certainly be a part of the professional contact lens practitioner’s armamentarium.

Currently the cost of such lenses is about half again as much as conventional soft lenses; they are technically difficult to manufacture; production and delivery tend to be slower than for conventional lenses; duplication is difficult; and they are trickier to fit. In addition, they don’t always produce a favorable or predictable visual correction. This is due in part to the problem of lens rotation, which the toric lens shares with the bifocal lenses discussed earlier. As soon as the lens rotates on the eye, the axis of astigmatism becomes displaced and the vision becomes blurred, particularly when the astigmatism is severe. To solve this problem, a variety of solutions have been devised, similar to those used to stabilize bifocal contact lenses.

Most commonly, prisms are placed in the lower parts of the lenses; the added plastic orients the lens by using gravity to keep the lens in alignment. Or a small segment may be cut off the bottom of the lens; this truncation results in a straight edge that stays aligned and parallel with the edge of the bottom eyelid. A lens may have the top or bottom portions or both portions made especially thin so they remain aligned underneath the eyelids; this is known as slab off. Finally, orientation grooves, a series of tiny vertical lines, may be cut into the top edge of the lens. The inner surface of the upper eyelid crosses the grooves, and with each blink the lid pulls the lens toward the top, keeping the lens oriented.

Most people think that cataracts develop only in their grandparents. In fact, though the average patient is seventy years old, cataracts can occur in anyone from the time of birth to over one hundred years of age. Another misconception is that a cataract is a film growing over the eye, when in reality it is the natural, transparent, crystalline lens of the eye that becomes cloudy. The light rays passing through the cloudy lens become obstructed and vision becomes more and more blurred as the condition worsens. Most often cataracts are part of the normal aging process, but they may also be caused by injury, disease, birth defects, infection, vitamin deficiency, radiation, and enzyme deficiencies.