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COMPLICATIONS ASSOCIATED WITH THERAPEUTIC SOFT CONTACT LENSES ANTHONY B. NESBURN, MD LOS ANGELES, CALIFORNIA The complications of therapeutic hydrophilic contact lens wear are systematically outlined. Hypoxia is the major cause of initial patient failure as well as the long-term problems of corneal edema, neovascularization, and susceptibility to infection. The common difficulties with lens breakage, lens deposits, poor lens retention, and other entities are discussed. Suggestions for avoiding and treating various complications are given, including updated indications and contraindications for fi tting these lenses. Careful patient selection and meticulous follow-up are essential.
STUDIES indicating the relatively low but extremely variable rate of serious complications involved with therapeutic soft contact lens (TSCL) wear were published some years ago. There have been no comprehensive reports updating the disparate clinical papers of Gasset,1-3 Dohlman 4.5 Gould 6 Brown 7 Ruben,8 Slatt and Stein:9 and oth~rs.lO·ll The need for new, extensive, statistically significant studies in
Submitted for publication Oct 24. 197R. From the Estelle Doheny Eye Foundation and the Department of Ophthalmology. University of Southern California School of Medicine. Los Angeles. This study was supported by Discovery Fund. Presented in combination with the Contact Lens Association of Ophthalmologists at the 197R An· nual Meeting of the American Academy of Oph· thalmology, Kansas City, Mo. Oct 22-26. Reprint requests to Estelle Doheny Eye Founda· tion. L'15f) San Pablo St, Los Angeles. CA 900:l".
this field is clear. This indicates either that there is no significant change in the complication profile or, more likely, little inclination of clinical investigators to compile and disseminate the data. Soon, updated information may be available from the strict FDA reporting requirements for investigational soft contact lenses now being tested for therapeutic purposes. This paper is written from an empirical practitioner's point of view. The important complications of therapeutic soft lens wear, some suggestions about handling these problems, and some current thoughts on indications and contraindications for TSCL fitting are discussed. A soft contact lens acts as a protective barrier, shielding the cornea from trauma and thereby aiding the healing process. The situation differs from cosmetic wear on two counts. There is a medical or therapeutic reason to apply the lens, and the cornea is usually compromised at the outset. Bearing in mind whether the lens is to be used for a short or an extended period, the tolerance of complications in any individual situation is colored by the need for the lens as a therapeutic appliance. As seen in the Table, the complications of TSCL wear are almost identical to those of soft contact lens wear in general. The complica-
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COMPLICATIONS AsSOCIATED WITH THERAPEUTIC SOFf CONTACT LENS WEAR
I. Lens-related complications A Initial lens application hypoxia B. Chronic hypoxia induced problems 1. Compromised epithelium 2. Stromal edema 3. Neovascularization C. Lens fitting problems D. Lens breakage II. Patient-related complications A Infectious conjunctivitis, red eyes, corneal ulcers B. Repeated lens loss or poor lens retention C. Unsuspected glaucoma III. Lens- and patient-related complications A Lens deposits B. Giant papillary conjunctivitis C. Corneal opacification D. Miscellaneous
tions can be arbitrarily divided into lens-related or patient-related causes. LENS-RELATED PROBLEMS Perhaps the most important parameter of lens function is proper oxygenation of the cornea with lids both open and closed. 12 Lack of oxygen is related directly or indirectly to hypoxic epithelial damage, corneal edema, and neovascuI ariz ation , as well as susceptibility to infection and ulceration. 13 These are the most serious complications of therapeutic contact lens wear. Hypoxic Epithelial Damage and Corneal EdemaAcute and Chronic In the United States, the two most commonly used therapeutic
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lenses, the Bausch & Lomb Plano-T and the Warner-Lambert Softcon lens, work moderately well. However, both suffer from relatively low oxygen transmissivity.12.14 Almost invariably, five to ten days of epithelial and stromal edema follows the initial application of either therapeutic lens. During this period, there is decreased vision, red eye, and discomfort or pain. This acute anoxic complication of soft contact lens wear is so unnerving to both ophthalmologist and patient that many patients never continue their lenses past this period. 9 The wearer must be carried over this stage with topical antibiotics, cycloplegics, hypertonic saline drops, and oral pain medication. Only then can the desired longer-term therapeutic effects of the lens be realized. Chronic hypoxic epithelial injury and stromal edema increase the susceptibility to infection and ulceration and also encourage neovascularization. In addition, stromal edema decreases visual acuity. These complications usually can be avoided by proper fitting, discontinuation of TSCL wear, or insertion of a more oxygen-permeable lens. 9 Neovascularization Superficial neovascularization of the cornea is almost universal if either therapeutic lens is worn long enough. 10. 13 Surface vessels in compromised eyes do not present a major problem since they rarely invade the visual axis or decrease vision to any notable extent. By contrast, stromal neovascularization, which is much rarer, can leave a dense, permanent opacity in the visual axis.10.11 Stromal neovascularization can be tolerated only in severe, vision-threatening situations,
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such as nonhealing stromal ulcers, or in eyes without much sight, such as painful, severe aphakic keratopathy. Exuberant stromal neovascularization that threatens vision is treated by discontinuing lens wear, a short course of topical corticosteroids, and possible refitting of a more oxygen-permeable lens. The newer soft contact lenses will alleviate most of the hypoxia-related complications. Many investigational lenses allow fitting of patients who could not tolerate the Plano-Tor Softcon lenses. The new lenses fall into two major catagories: (1) the ultrathin, low water content lenses (Bausch & Lomb, Corneal Sciences, Inc, Hydrocurve) and (2) higher water content lenses (Cooper, Sauflon). While each of these lenses has its own particular problems, none of them produces as much acute or chronic hypoxia-related damage as currently available lenses.
Lens Fitting Problems
Lens-related problems often are eliminated by using a thin, large, extremely pliable, one-size-fits-all lens such as the Plano-To However, some eyes will not tolerate this and require more precise fitting with a lens in the Softcon series. With the Softcon lens, one should choose the thinnest lens available (even if it means fitting a low minus power rather than plano) that produces a "normal" or slightly loose fit with about 1 mm of movement on a blink. This more physiologic approach to fitting is preferred by many practitioners who feel that it minimizes mechanical damage, hypoxia, and variablity in vision in extended wear. Limbal compression of a tight lens must be avoided.
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Lens Breakage
Lens breakage and ease of handling of both FDA-accepted and investigational lenses are related to the friability of the lens material and the thickness of the lens. The thin, tougher plastics are hard to handle because of their floppiness and are easily torn because they are so thin. The thicker, higher water content lenses are easier to handle but are less durable, because of the lower tensile strength of the plastic. PATIENT-RELATED COMPLICATIONS Infections, Conjunctivitis, Red Eyes, and Corneal Ulcers
Infections in the form of conjunctivitis or, rarely, corneal ulceration are, in part, a predictable consequence of the normal bacterial flora of the conjunctival cul-de-sac. The organisms encountered include a long list of bacteria and fungi. Most prevalent are Staphylococcus epidermidis, Staphylococcus aureus, Corynebacterium organisms, Streptococcus organisms, and a scattering of gram negatives, including Serratia organisms, Pseudomonas organisms, Proteus organisms, and Escherichia coli. I5 •I6 It is not known what causes the quiet eye wearing a therapeutic lens to produce conjunctivitis or corneal infiltration. Certainly, hypoxic damage to the corneal epithelial barrier must play some part. A common experience of many practitioners is the onset of a red eye or infectious episode immediately following routine lens removal, cleaning, and reinsertion. This has led many to clean and sterilize therapeutic lenses on an
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"as needed" basis only. Many patients' lenses have remained untouched for 6 to 12 months or longer.
lems related to trichiasis and lid deformities, and unsuspected glaucoma.
The question of whether to employ prophylactic antibiotics to prevent infection seems to have been partially answered by the studies of Binder and Worthen. 15 These studies show no change in the conjunctival flora using neomycin sulfate, polymyxin, and gramicidin (Neosporin) and chloramphenicol using up to one drop four times a day. The studies do not show whether these antibiotics protect the cornea with a lens in place. However, many practitioners have encountered infections in patients using prophylactic topical antibiotics. Until there is definitive data showing that such antibiotic use is contraindicated, many have elected to folIowa regimen including (1) prophylactic antibiotics (but not ones used to treat severe ulcers, such as gentamicin) four to six times a day for the first few days of therapeutic wear, with eventual discontinuation for the long term, (2) cleaning of t~e ~ashes and lid margins, (3) restnctlOn of lenses to patients with good hygiene, (4) aseptic insertion of the lenses, and (5) cautious use of topical corticosteroids.
Lens Loss
A red and painful eye, corneal ulcer, or infiltrate that develops in a formerly comfortable patient while a TSCL is worn must be handled as' an active bacterial infection. Bacterial and fungal cultures must be taken, the lens must be removed and appropriate topical or subconjunctival therapy is begun immediately.13 Other patient-related complications of therapeutic soft contact lens wear include lens loss, prob-
Assuming that a lens has been fitted properly, poor retention or loss of lenses is most often related to poor blinking and lid closure. This produces drying and outturning of the lens edges in the palpebral fissure zone, which results in the lens being expressed from the eye on blinking. To correct the situation, dry eyes, incomplete blinking, lagophthalmos, and nocturnal separation of the lids must be actively sought and treated. Patients in this group must use frequent tear replacement drops, such as hypotonic artificial tears or half normal saline without preservatives, and bland ointment at bedtime. Additional measures can be taken for the individual problems involving lens loss and lens drying: (1) In the severely affected dry eye patient, the puncta should be closed with cautery. (2) Incomplete closure of the lids on blinking can be improved by encouraging frequent blinking and eye closure. (3) Patients with prominent eyes and mild to moderate lagophthalmos (4 to 5 mm of inferior sclera showing) should have a permanent lateral one-third tarsorrhaphy. (4) Those suffering from nocturnal lagophthalmos need to tape their lids at night after instilling bland antibiotic or petrolatum-based ointment. Lid Deformity and Trichiasis
Lid deformities such as ectropion entropion, and prominent conjunc: tival scars tend to dislodge lenses and promote infection. These con-
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ditions should be corrected with appropriate surgical technique. Trichiasis can be a stubborn problem that, in addition to displacing lenses, brings contaminated lashes in direct contact with the eye and lens, increasing the possibility of infection. This is of particular importance in patients with pemphigoid and Stevens-Johnson syndrome, who are especially susceptible to ocular infection. The recent use of carefully monitored liquid nitrogen application for permanent destruction of hair follicles has been tremendously successful in solving the trichiasis problem. Certainly, this is a more satisfactory and humane solution than repeated, painful, and often unsuccessful attempts at lash removal by hydrolysis of individual inturned lashes. Unsuspected Glaucoma
Unsuspected glaucoma in patients wearing therapeutic soft contact lenses can be a devastating complication resulting in extensive field loss. Most patients' intraocular pressure should be checked at every visit. Whenever the lens is removed for cleaning, applanation or Schiotz tension should be taken. Since cleaning is only carried out at long intervals, the McKay-Marg tonometer is nearly indispensible. With topical anesthetic, the McKayMarg probe with its sterile cover can be used to check the pressure through the lens. The probe is applied to the thinnest part of the lens over the cornea, which is usually near the limbus. This method becomes easy with practice. McKay -Marg pressures taken through a lens are falsely high and vary directly with lens thickness.
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In lenses less than 0.3 mm thick, they measure from 2 to 10 mm higher than the direct corneal readings. Pressures recorded through lenses thicker than 0.3 mm are unreliable and are much higher than normal. Therefore, if the pressure recorded through a thin lens is under 22, it can be considered normal. It is wise to make a note that the lOP was taken through the lens. If a high pressure is obtained, the lens is gently pushed aside with a sterile covered tonometer tip and the pressure then taken directly on the cornea. The lens is repositioned with the sterile covered probe tip. In this way, tension can be checked without using fluorescein and without physically removing the lens from the eye, avoiding problems of contamination. Appropriate therapy for glaucoma, including most topical agents, can be carried out with the lens in place. The only exception is topical epinephrine, which discolors lenses. A new drug, dipivalyl epinephrine, has been shown to control pressure without discoloring lensesP This drug is a helpful adjunct to glaucoma therapy in patients who must wear therapeutic lenses. LENS- OR PATIENT-RELATED COMPLICATIONS
Lens deposits, giant papillary conjunctivitis, corneal opacities, corneal wettability changes, change in corneal curvature, and sensitivity vary in importance from extreme to negligible. Deposits
Lens deposits are the most common cause for therapeutic lens spoilage and replacement. These
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deposits are of two main types. Some are slightly opaque and 0.5 to 1.0 mm in. diameter with smooth or scalloped borders, these appear to be of proteinaceous origin. The other common variety is multiple, fine, 0.25 mm in diameter, white, slightly rounded deposits that are thought to contain calcium. Chemical analyses of soft contact lens deposits have yielded varying resultS. I6 • I8 Patients appear to be prone to either one t.ype of deposit or the other, although many never have them at all. While most patients produce deposits slowly over several months, some patients have been observed to form them within a week of inserting a new lens. Deposits most commonly form within the palpebral fissure area. This has led to theories proposing surface concentration of tear components by evaporation as the main cause. Clinically, deposits can produce discomfort and decreased vision. Excessive movement of the lens as the patient blinks leads to further variation in vision and discomfort. The giant papillary conjunctivitis syndrome as described by Allansmith et a}19 occurs frequently in patients with and without lens deposits. The fitter should be alerted to this phenomenon by excess mucous production and slight ptosis of the upper lid, as well as complaints of blurred vision and excessive lens movement. The diagnosis is confirmed by finding the typical papillary changes of the upper palpebral conjunctiva. Both papillary hypertrophy and lens deposit formation can force the discontinuation of TSCL wear. In each therapeutic situation, it
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must be decided whether frequent cleaning of the lens to prevent deposit and protein buildup is better for the patient than discontinuation of the lens therapy itself. Deposit formation requiring frequent and expensive replacement of contact lenses has been a major reason for treatment failure. Cleaning systems advocated by various manufacturers to prevent or retard deposit formation are far from ideal. Further investigation is necessary to find the causes as well as better means of deposit prevention and removal. Corneal Opacities
Rarely, a noninfectious corneal opacity similar to the type seen in epidemic keratoconjunctivitis is encountered in patients wearing TSCLs.5 Their origin is unclear. In some cases, the opacity may well be due to an adenoviral infection; in most, no conjunctivitis or virus isolation has accompanied the condition. Occasionally, hypersensitivity type (ie, staphylococcal) infiltrates are seen. In these patients, short-term topical antibiotics and, more importantly, long-term treatment for staphylococcal blepharitis or elimination of the sensitizer is indicated. Corneal opacities that can significantly affect visual acuity follow infectious corneal ulcers and stromal neovascularization with lipid deposition around leaky capillaries. Vigorous prevention and therapy of infectious ulcers have been advocated for the former problem. The latter is treated by discontinuing the therapeutic lens if stromal vessels encroach on the visual axis, and concomitant use of topical
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corticosteroids to help close vessels, if the corneal condition permits. Abnormalities of Corneal Surface In some instances, when therapeutic lenses are removed, there appears to be a deficiency or abnormality of corneal wetting. In patients without lid deformities or a dry eye syndrome, this condition reverts to normal after the lens has been removed for one to two weeks. Artificial tears and bland ointment are helpful. Alterations in Corneal Curvature and Sensation Small changes in corneal curvature, usually 0.25 to 1.00 diopter steepening with slight increase in myopia are reported. 9 Decrease in corneal sensitivity that appears to revert to normal after discontinuing lens wear has been noted in some prolonged soft contact lens wearers.
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these complications will depend upon the seriousness of the entity being treated by lens wear. Short-Term and Long-Term TSCL Indications and Contraindications In general, the use of soft contact lenses for short-term indications has been most successful. These include healing of epithelial ulcers, stromal noninfected ulceration, small corneal perforations and lacerations, short-term protection of the cornea from lid deformities or trichiasis, treatment of the recurrent erosion syndrome, and filamentary keratopathy. Short-term application of lenses in the later stages of herpetic keratitis has been thought to help quiet the eye.
Of long-term therapeutic situations, control of pain in bullous keratopathy has been rewarding. By contrast, only rarely can patients with the severe dry eye syndromes be helped on a long-term basis. Individuals with mild dry eye symptoms usually do not tolerate COMMENT prolonged wear of lenses well. N eurotrophic keratopathy can be treated Many, but by no means all, ofthe on a long-term basis, but usually complications of therapeutic soft at the expense of corneal neovascontact lens wear have been de- cularization. However, this does lineated here. Where possible, sug- allow the patient to avoid a tarsorgestions have been made to help the rhaphy. Neuroparalytic disease usupractitioner cope with these prob- ally requires lid surgery, since exlems. posure causes drying of soft contact lenses and does not allow the It must be reemphasized that pa- lens to stay on the eye. Permatient selection and careful follow-up nent trichiasis and lid deformities are extremely important in minimiz- should be treated surgically, not ing ocular damage from TSCL with soft contact lenses. wear. Patients should be instructed to call the ophthalmologist at the first sign of a problem. The patient MISCELLANEOUS SUGGESTIONS or someone close to him should be able to remove the lens in case of an emergency. The ophthalmoloOther helpful suggestions include gist's and the patient's tolerance for the following: (1) Sterile insertion of
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the lens using sterile cotton swabs or talc-free gloves can be helpful. (2) In nonhealing ulcers, if a lens keeps coming out, cyanoacrylate adhesive can be applied to the base of the ulcer, and before the adhesive polymerizes completely, the soft contact lens applied. This maneuver produces the needed adherence of the lens to the eye over the adhesive treated ulcer. (3) Corneal epithelial problems, such as map-dot-fingerprint dystrophy, are amenable to debridement with application of a soft contact lens. (4) Overrefraction of a TSCL is made easier and faster by taking K readings over the lens to help determine the amount and axis of residual astigmatism. Improvement in soft contact lens technology will greatly aid the success of therapy. Higher oxygen permeable materials with higher tensile strength, whose surfaces are more resistant to deposits, will alleviate many of the problems presently encountered in soft contact lens therapy. REFERENCES 1. Gasset AR, Kaufman HE: Bandage lenses in the treatment of bullous kera· topathy. Am J Ophthalmol 72:376-380, 1971.
2. Gasset AR, Kaufman HE: Hydrophilic lens therapy of superficial sterile corneal ulcers. Ann Ophthalmol 5:139-142, 1973. 3. Gasset AR, Lobo L, Houde W: Permanent wear of soft contact lenses in aphakic eyes. Am J Ophthalmol 83:115-120, 1977. 4. Dohlman CH, Boruchoff SA, Mobilia EF: Complications in use of soft contact lenses in corneal disease. Arch Ophthalmol 90:867-371, 1973. 5. Dohlman CH: Complications in therapeutic soft lens wear. Trans Am Acad Ophthalmol Otolaryngol 78:0P-399-0P-405, 1974.
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6. Gould HL: Therapeutic experience with soft contact lenses. Trans Am Acad Ophthalmol Otolaryngol 78:0P-391-0P-398, 1974. 7. Brown SI, Bloomfield S, Pearce DB, et al: Infections with the therapeutic soft lens. Arch Ophthalmol 91:275-277, 1974. 8. Ruben M: Soft contact lens treatment of bullous keratopathy. Trans Ophthalmol Soc UK 95:75-78, 1975. 9. Stein H, Slatt B: Complications of prolonged wear hydrogel lenses. Int Contact Lens Clin 4:1977. 10. Schecter DR, Emery JM, Soper JW: Corneal neovascularization in therapeutic soft lens wear. Contact Intraocular Lens Med J 1:141-145, 1975. 11. Weinberg RJ: Deep corneal neovascularization caused by aphakic soft contact lens wear. Am J Ophthalmol 8:3:121-122, 1977. 12. Mobilia EF, Dohlman CH, Holly FJ: A comparison of various contact lenses for therapeutic purposes. Contact Lens J :3:9-15, 1977. 13. Nesburn AB: Prolonged-wear contact lenses in aphakia. Ophthalmology 85:73-79, 1978. 14. Morris JA, Fatt I: A survey of gaspermeable contact lenses. Optician 175:2734, 1977. 15. Binder PS, Worthen DM: A continuous-wear hydrophilic lens: Prophylactic topical antibiotics. Arch Ophthalmol 94:21092111, 1976. 16. Cooper RL, Constable IJ: Infective keratitis in soft contact lens wearers. Br J Ophthalmol 61:25()'254, 1977. 17. Newton MJ, Nesburn AB: Lack of hydrophilic lens discoloration in patients using dipivalyl epinephrine for glaucoma. Am J Ophthalmol 87:193-195, 1979. 18. Ganju SN, Cordrey P: A study of deposits on extended wear soft contact lenses made from Sauflon 85. Optician 173:8-16, 1977. 19. Allansmith MR, Korb DR, Greiner JV, et al: Giant papillary conjunctivitis in contact lens wearers. Am J Ophthalmol 83: 697-708, 1977.