Symposium: Contact Lens and Spectacle Lens Correction of Aphakia f
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PROBLEMS ASSOCIATED WITH PROLONGED WEAR SOFr CONTACT LENSES HERBERT E. KAUFMAN, MD NEW ORLEANS, LOUISIANA
Complications of prolonged wearing of soft contact lenses are corneal infection, peripheral vascularization, giant papillary conjunctivitis and allergy, sterile ulcers, corneal warping, lens infection, protein and calcium deposits, lens fragility, and problems with disinfecting solutions. Further long-term studies are needed to compare the safety of prolonged wear soft contact lenses with the safety of intraocular lenses, on which long-term studies are currently being done.
IN choosing a rational treatment for a patient, it must be decided with the patient whether the risks are worth the benefits, and whether, in fact, there are safer ways to accomplish the desired goals than those now being used. One of the primary purposes of prolonged wear of contact lenses is the correction of aphakia, and the risks and benefits of contact lenses must be balanced against those of intraocular lenses and spectacles, with regard to the problems spectacle wearers have with visual function.
ways: complications of lens wear in relation to the eye and problems of the lens itself. In addition, there may be other problems if use becomes widespread and nonmedical practitioners begin to dispense prolonged wear lenses. EYE PROBLEMS WITH PROLONGED WEAR SOFI' LENSES
Infection Infection is the most devastating complication of contact lens wear. When a serious corneal ulcer occurs, it often means functional loss of vision in the eye (Fig 1 through 4). This complication is irreversible and cannot be helped simply by removing the lens.
Prolonged wear contact lenses will be considered in two different Submitted for publication Oct 25, 1978. From the Louisiana State University Medical Center, New Orleans. Presented in combination with the Contact Lens Association of Ophthalmologists at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26. Reprint requests to LSU Eye Center, 136 S Roman St, New Orleans, LA 70112 (Dr Kaufman) .
Fig 1.-Ring shaped corneal ulcer caused by Serratia marcescens in patient with prolonged wear lens.
411
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HERBERT E. KAUFMAN
Fig 2.-Pseudomonas ulcer in patient with pro· longed wear soft contact lens.
OPHTH AAO
tion is likely to be more common when lenses are no longer under study and when hygiene is no longer as rigidly stressed as it was in the study. The risk of infection does not appear to decrease with time. On the contrary, the risk may increase as the lenses are worn over a period of years. This may be a function not only of susceptibility of the eye to the lens but also of the normal decrease in tear flow with age, since there is no question that dry eyes increase the risk of infection. In order to assess the magnitude of this complication, it will be necessary to have good incidence figures-not just for a short term after the lenses are dispensed, b\lt over a period of five or ten years, since the risk does not appear to decrease with time. It is essential to analyze these risks in order to compare them with the risks of intraocular lenses.
Fig 3.-Pseudomonas corneal ulcer in patient with prolonged wear lens.
Conjunctivitis and external ocular mfections also occur with these lenses. During a period of intensive study it is likely that these infections will be managed promptly and will not lead to serious eye damage; however, the risk of serious complications occurring after control has been relaxed may well be much greater. Vascularization
Fig 4.-Staphylococcus aureus ulcer in patient with prolonged wear lens.
The true incidence of infection with prolonged wear soft lenses is not known. Several points have been established, however. Infec-
Virtually all patients who wear prolonged wear soft lenses have some peripheral vascularization with time (Fig 5). A certain percentage of people have more extensive vascularization and deep vascularization (Fig 6). This may be due to a relative degree of anoxia, but vascularization also is seen with daily
VOLUME 86 MARCH 1979
SYMPOSIUM ON APHAKIA
wear of hard lenses. Although vessel ingrowth is rare with hard lenses compared with prolonged wear soft lenses, it has not been proven that lenses with greater oxygen permeability will eliminate vascularization of the cornea. It is not clear how the susceptibility to vascularization varies in the population, but since some people vascularize extensively and rapidly, this may not be predictable. Vascularization is not necessarily at its peak during the initial time of study, and this problem needs to be followed for many years, as do the complications of intraocular lenses.
Fig 5.-Moderately heavy peripheral vascularization of cornea from prolonged lens wear.
413
Vascularization is less of a problem than infection, since vessels usually regress when lens wear is discontinued. This means, however, that the prolonged wear lenses cannot be used, and a disability such as monocular aphakia cannot be corrected. Giant Papillary Conjunctivitis and Allergy
This complication, originally described by Spring1 and further elucidated by the studies of Allansmith and others, 2 can be accompanied by symptoms of such intense itching and burning that lens wear must be discontinued. Although permanent damage to the lids and cornea from this is not usually seen, the discomfort results in discontinuing use of the lens. Part of the difficulty with giant papillary conjunctivitis is that the incidence of this complication that terminates lens wear appears to increase as a function of time. Some experienced lens fitters feel that a high proportion of patients will aquire this problem if soft lenses are worn long enough, and again, a prolonged experience over many years is required to accurately determine the risk. Sterile Corneal Ulcers
Fig 6.-Heavy, rapidly developing central vascularization in patient with prolonged wear soft contact lens.
These ulcers, at one time thought to be pressure ulcers, occur in contact lens patients and are of uncertain cause. They may be small round focal ulcers in the center of the cornea or in the periphery. Sometimes ring ulcers, which are necrotizing and produce terrible corneal damage, are seen with soft contact lenses. The cause of these is not clear. If these ulcers are detected
HERBERT E. KAUFMAN
414
early, the lenses can be removed, and often damage to the cornea is minimized. Some, on the other hand, are so serious when first seen that permanent visual damage results. As lenses become more available and as patients are less closely followed and perhaps less closely screened in terms of patient selection and reliability, complications resulting from sterile ulcers may increase. Corneal Warping Corneal warping with resultant induction of high astigmatism occurs in a small proportion of prolonged wear users. It can result in permanently high astigmatism and refractive error. Solutions The available disinfecting solutions and boiling procedures bring with them their own set of problems. A significant number of people who use solutions containing thimerosal over a long period of time acquire severe medication intolerance. This is usually not signaled by the itching and contact dermatitis seen with atropine, but rather with a burning discomfort that makes lenses intolerable. If it is recognized, discontinuation of fluid sterilization and a change of lenses may permit continued use of the lenses. Although this is less common with prolonged wear soft lenses, which do not require frequent cleansing, it must nevertheless be considered. Similarly, the mucous-binding properties of solutions containing chlorhexidine hydrochloride can make lenses hydrophobic and, by binding protein to the surface, perhaps increase the incidence of giant
OPHTH AAO
papillary conjunctivitis and shorten the life and tolerability of the lens. LENS PROBLEMS WITH PROLONGED WEAR SOFI' LENSES Lens Infection The lenses themselves present one of the most serious problems with prolonged wear, lens infection. The lenses have a pore size that is generally too small for microbial organisms to enter. However, there are now a number of cases documented in which organisms such as fungi attach to the surface of the lens (Fig 7 and 8) and digest the lens material while growing into it (Fig 9 and 10). Fungus infections can develop on the lens while the lens is in the patient's eye. This can sometimes happen without any damage to the eye at all. Nevertheless, as prolonged wear lenses become more commonplace, the problem may become magnified. Fungus infections may first appear as nondescript white deposits or as fluid. These deposits are much more
Fig 7.-Fungus deposit on prolonged wear lens.
VOLUM E 86 MARCH 1979
SYMPOSIUM ON APHAKIA
415
Fig 8.-Fungus deposits on surface of prolonged wear lens (x50).
likely to occur in prolonged wear lenses than in lenses that are cleaned daily. Protein and Calcium Deposits Protein 'deposits occur on contact lenses, and mucoproteins can adhere to the surface, rendering the lenses unusable. Patients with certain allergies appear more prone to this problem, but deposits generally occur in an unpredictable manner. Some patients can wear a lens only a few weeks before it becomes un-
usable owing to deposits. Sometimes these deposits can be removed by cleaning the lens, but those patients with chronic deposit formation cannot, in any practical way, wear lenses on a prolonged-wear basis. Calcium as well as protein can accumulate on the lens surface. These are smaller, rounder, harder opacities, as a rule. The source of the calcium is not clear, but Uotila 3 has demonstrated that there is calcium in tears, and the working hypothesis is that tear calcium precipi-
416
HERBERT E. KAUFMAN
OPHTH AAO
Fig 9.-Fungus eating into soft contact lens.
tates on and in the lens substance. It is not known whether this is a function of the total amount of calcium produced or of the pH of the milieu; nevertheless, these deposits can render the lens unusable.
Certain kinds of lenses seem more prone to deposits than others. Although definitive data are not available, silicone lenses appear to have a greater tendency to form deposits than do other hydrogel lenses.
VOLUME 86 MARCH 1979
SYMPOSIUM ON APHAKIA
417
COMMENT
This discussion must be interpreted with care. No attempt is being made to indicate that soft contact lenses are unduly hazardous or more hazardous than intraocular lenses or other types of refractive corrections.
Fig 10.-Fungus in prolonged wear lens while lens is still being worn by patient.
Most modalities have both advantages and disadvantages. The exact risks of prolonged soft contact lens wear have not been thoroughly documented, and there seems to be an unjustified feeling that some modalities such as intraocular lenses are dangerous while soft contact lenses are safe. Soft contact lenses may be safer, but this has not yet been established. Only longterm follow-up, comparable to that required for intraocular lenses, will establish it. The potential impact of widespread dispensing and care by nonmedical practitioners must also be considered. ACKNOWLEDGMENTS
Lens Fragility The typical lens life remains uncertain and presumably varies from manufacturer to manufacturer. Patients selected for initial studies are particularly suitable for lens wear and can handle lenses well. However, the eventual necessity of removing lenses, even occasionally, may result in a shortened lens life, as has been documented in all soft contact lens studies thus far.
Figures 8 and 9 were provided by Atsushi Kanai, MD, Department of Ophthalmology, Juntendo University, Tokyo.
REFERENCES 1. Spring TF: Reaction to hydrophilic lenses. Med J Aust 1:499-500, 1974.
2. Allansmith MR, Korb DR, Greiner JV, et al: Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmo/83:697708 , 1977. 3. Uotila MH , sOble RE, Savory J : Measurement of tear calcium levels. Invest Ophthalmol 11:258-259, 1972.
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PROBLEMS ASSOCIATED WITH PROLONGED WEAR SOFr CONTACT LENSES HERBERT E. KAUFMAN, MD NEW ORLEANS, LOUISIANA
Complications of prolonged wearing of soft contact lenses are corneal infection, peripheral vascularization, giant papillary conjunctivitis and allergy, sterile ulcers, corneal warping, lens infection, protein and calcium deposits, lens fragility, and problems with disinfecting solutions. Further long-term studies are needed to compare the safety of prolonged wear soft contact lenses with the safety of intraocular lenses, on which long-term studies are currently being done.
IN choosing a rational treatment for a patient, it must be decided with the patient whether the risks are worth the benefits, and whether, in fact, there are safer ways to accomplish the desired goals than those now being used. One of the primary purposes of prolonged wear of contact lenses is the correction of aphakia, and the risks and benefits of contact lenses must be balanced against those of intraocular lenses and spectacles, with regard to the problems spectacle wearers have with visual function.
ways: complications of lens wear in relation to the eye and problems of the lens itself. In addition, there may be other problems if use becomes widespread and nonmedical practitioners begin to dispense prolonged wear lenses. EYE PROBLEMS WITH PROLONGED WEAR SOFI' LENSES
Infection Infection is the most devastating complication of contact lens wear. When a serious corneal ulcer occurs, it often means functional loss of vision in the eye (Fig 1 through 4). This complication is irreversible and cannot be helped simply by removing the lens.
Prolonged wear contact lenses will be considered in two different Submitted for publication Oct 25, 1978. From the Louisiana State University Medical Center, New Orleans. Presented in combination with the Contact Lens Association of Ophthalmologists at the 1978 Annual Meeting of the American Academy of Ophthalmology, Kansas City, Mo, Oct 22-26. Reprint requests to LSU Eye Center, 136 S Roman St, New Orleans, LA 70112 (Dr Kaufman) .
Fig 1.-Ring shaped corneal ulcer caused by Serratia marcescens in patient with prolonged wear lens.
411
412
HERBERT E. KAUFMAN
Fig 2.-Pseudomonas ulcer in patient with pro· longed wear soft contact lens.
OPHTH AAO
tion is likely to be more common when lenses are no longer under study and when hygiene is no longer as rigidly stressed as it was in the study. The risk of infection does not appear to decrease with time. On the contrary, the risk may increase as the lenses are worn over a period of years. This may be a function not only of susceptibility of the eye to the lens but also of the normal decrease in tear flow with age, since there is no question that dry eyes increase the risk of infection. In order to assess the magnitude of this complication, it will be necessary to have good incidence figures-not just for a short term after the lenses are dispensed, b\lt over a period of five or ten years, since the risk does not appear to decrease with time. It is essential to analyze these risks in order to compare them with the risks of intraocular lenses.
Fig 3.-Pseudomonas corneal ulcer in patient with prolonged wear lens.
Conjunctivitis and external ocular mfections also occur with these lenses. During a period of intensive study it is likely that these infections will be managed promptly and will not lead to serious eye damage; however, the risk of serious complications occurring after control has been relaxed may well be much greater. Vascularization
Fig 4.-Staphylococcus aureus ulcer in patient with prolonged wear lens.
The true incidence of infection with prolonged wear soft lenses is not known. Several points have been established, however. Infec-
Virtually all patients who wear prolonged wear soft lenses have some peripheral vascularization with time (Fig 5). A certain percentage of people have more extensive vascularization and deep vascularization (Fig 6). This may be due to a relative degree of anoxia, but vascularization also is seen with daily
VOLUME 86 MARCH 1979
SYMPOSIUM ON APHAKIA
wear of hard lenses. Although vessel ingrowth is rare with hard lenses compared with prolonged wear soft lenses, it has not been proven that lenses with greater oxygen permeability will eliminate vascularization of the cornea. It is not clear how the susceptibility to vascularization varies in the population, but since some people vascularize extensively and rapidly, this may not be predictable. Vascularization is not necessarily at its peak during the initial time of study, and this problem needs to be followed for many years, as do the complications of intraocular lenses.
Fig 5.-Moderately heavy peripheral vascularization of cornea from prolonged lens wear.
413
Vascularization is less of a problem than infection, since vessels usually regress when lens wear is discontinued. This means, however, that the prolonged wear lenses cannot be used, and a disability such as monocular aphakia cannot be corrected. Giant Papillary Conjunctivitis and Allergy
This complication, originally described by Spring1 and further elucidated by the studies of Allansmith and others, 2 can be accompanied by symptoms of such intense itching and burning that lens wear must be discontinued. Although permanent damage to the lids and cornea from this is not usually seen, the discomfort results in discontinuing use of the lens. Part of the difficulty with giant papillary conjunctivitis is that the incidence of this complication that terminates lens wear appears to increase as a function of time. Some experienced lens fitters feel that a high proportion of patients will aquire this problem if soft lenses are worn long enough, and again, a prolonged experience over many years is required to accurately determine the risk. Sterile Corneal Ulcers
Fig 6.-Heavy, rapidly developing central vascularization in patient with prolonged wear soft contact lens.
These ulcers, at one time thought to be pressure ulcers, occur in contact lens patients and are of uncertain cause. They may be small round focal ulcers in the center of the cornea or in the periphery. Sometimes ring ulcers, which are necrotizing and produce terrible corneal damage, are seen with soft contact lenses. The cause of these is not clear. If these ulcers are detected
HERBERT E. KAUFMAN
414
early, the lenses can be removed, and often damage to the cornea is minimized. Some, on the other hand, are so serious when first seen that permanent visual damage results. As lenses become more available and as patients are less closely followed and perhaps less closely screened in terms of patient selection and reliability, complications resulting from sterile ulcers may increase. Corneal Warping Corneal warping with resultant induction of high astigmatism occurs in a small proportion of prolonged wear users. It can result in permanently high astigmatism and refractive error. Solutions The available disinfecting solutions and boiling procedures bring with them their own set of problems. A significant number of people who use solutions containing thimerosal over a long period of time acquire severe medication intolerance. This is usually not signaled by the itching and contact dermatitis seen with atropine, but rather with a burning discomfort that makes lenses intolerable. If it is recognized, discontinuation of fluid sterilization and a change of lenses may permit continued use of the lenses. Although this is less common with prolonged wear soft lenses, which do not require frequent cleansing, it must nevertheless be considered. Similarly, the mucous-binding properties of solutions containing chlorhexidine hydrochloride can make lenses hydrophobic and, by binding protein to the surface, perhaps increase the incidence of giant
OPHTH AAO
papillary conjunctivitis and shorten the life and tolerability of the lens. LENS PROBLEMS WITH PROLONGED WEAR SOFI' LENSES Lens Infection The lenses themselves present one of the most serious problems with prolonged wear, lens infection. The lenses have a pore size that is generally too small for microbial organisms to enter. However, there are now a number of cases documented in which organisms such as fungi attach to the surface of the lens (Fig 7 and 8) and digest the lens material while growing into it (Fig 9 and 10). Fungus infections can develop on the lens while the lens is in the patient's eye. This can sometimes happen without any damage to the eye at all. Nevertheless, as prolonged wear lenses become more commonplace, the problem may become magnified. Fungus infections may first appear as nondescript white deposits or as fluid. These deposits are much more
Fig 7.-Fungus deposit on prolonged wear lens.
VOLUM E 86 MARCH 1979
SYMPOSIUM ON APHAKIA
415
Fig 8.-Fungus deposits on surface of prolonged wear lens (x50).
likely to occur in prolonged wear lenses than in lenses that are cleaned daily. Protein and Calcium Deposits Protein 'deposits occur on contact lenses, and mucoproteins can adhere to the surface, rendering the lenses unusable. Patients with certain allergies appear more prone to this problem, but deposits generally occur in an unpredictable manner. Some patients can wear a lens only a few weeks before it becomes un-
usable owing to deposits. Sometimes these deposits can be removed by cleaning the lens, but those patients with chronic deposit formation cannot, in any practical way, wear lenses on a prolonged-wear basis. Calcium as well as protein can accumulate on the lens surface. These are smaller, rounder, harder opacities, as a rule. The source of the calcium is not clear, but Uotila 3 has demonstrated that there is calcium in tears, and the working hypothesis is that tear calcium precipi-
416
HERBERT E. KAUFMAN
OPHTH AAO
Fig 9.-Fungus eating into soft contact lens.
tates on and in the lens substance. It is not known whether this is a function of the total amount of calcium produced or of the pH of the milieu; nevertheless, these deposits can render the lens unusable.
Certain kinds of lenses seem more prone to deposits than others. Although definitive data are not available, silicone lenses appear to have a greater tendency to form deposits than do other hydrogel lenses.
VOLUME 86 MARCH 1979
SYMPOSIUM ON APHAKIA
417
COMMENT
This discussion must be interpreted with care. No attempt is being made to indicate that soft contact lenses are unduly hazardous or more hazardous than intraocular lenses or other types of refractive corrections.
Fig 10.-Fungus in prolonged wear lens while lens is still being worn by patient.
Most modalities have both advantages and disadvantages. The exact risks of prolonged soft contact lens wear have not been thoroughly documented, and there seems to be an unjustified feeling that some modalities such as intraocular lenses are dangerous while soft contact lenses are safe. Soft contact lenses may be safer, but this has not yet been established. Only longterm follow-up, comparable to that required for intraocular lenses, will establish it. The potential impact of widespread dispensing and care by nonmedical practitioners must also be considered. ACKNOWLEDGMENTS
Lens Fragility The typical lens life remains uncertain and presumably varies from manufacturer to manufacturer. Patients selected for initial studies are particularly suitable for lens wear and can handle lenses well. However, the eventual necessity of removing lenses, even occasionally, may result in a shortened lens life, as has been documented in all soft contact lens studies thus far.
Figures 8 and 9 were provided by Atsushi Kanai, MD, Department of Ophthalmology, Juntendo University, Tokyo.
REFERENCES 1. Spring TF: Reaction to hydrophilic lenses. Med J Aust 1:499-500, 1974.
2. Allansmith MR, Korb DR, Greiner JV, et al: Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmo/83:697708 , 1977. 3. Uotila MH , sOble RE, Savory J : Measurement of tear calcium levels. Invest Ophthalmol 11:258-259, 1972.
