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. Read the rest of this entry »
These are the questions asked most frequently by my patients. If you have any others, consult your contact lens specialist.
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.” Read the rest of this entry »
A bandage lens, also called a therapeutic lens, is a special soft, very thin, high-water-content contact lens. In 1974 this hydrophilic lens was the first type to be used on an extended-wear basis, but without incorporating a prescription. It has a wide variety of uses before ocular surgery, after ocular surgery, and sometimes instead of surgery. It can also be therapeutic in conditions that do not respond to any other form of treatment.
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). Read the rest of this entry »
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.
Keratoconus is a relatively common hereditary disorder that manifests itself in adolescence. It affects both eyes, but one eye usually progresses faster than the other. During the course of this disease the cornea changes from its round shape to that of a cone, hence the name: kera meaning “cornea” and conus meaning “cone.” The apex of the cone is thin and may become scarred. In severe cases the apex may actually perforate.
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.
Conventional soft contact lenses cannot be used to correct moderate to large amounts of astigmatism. Their pliable nature causes them to conform to irregularities in the shape of the cornea and thus duplicate the astigmatic refractive error. Hard contact lenses are firm and hold their shape; they are able to correct high amounts of astigmatism because the spherical undersurface of the lenses and the tears beneath them create a new, smooth optical surface. Read the rest of this entry »
Contact Lenses Care .
