2000 Extended wear cases: A retrospectivesurvey of contact lens complications

Journalofthe B.C.L.A.Vol. 10. No. 1, pp. 13 - 15, 1987 Printedin GreatBritain

©1987 by the BritishContactLensAssoc.

2000 EXTENDED WEAR CASES: A RETROSPECTIVE SURVEY OF CONTACT LENS COMPLICATIONS R o Y H . RENGSTORFF*, KLAS T. NILSSONd-, ANNA E . SYLVANDERt

(Received 20 July 1986, in revised form 7 November 1986) Abstract -- A retrospective study of 2000 patients fitted with extended wear hydrophilic lenses (Scanlens 75 ®) between 1975 and 1983 showed the number of successful cases to be 1740 (87%). Unsuccessful patients reverted to either dally wear hydrophilic lenses, gas-permeable or PMMA lenses or spectacles. Most patients wore lenses 30 or more days before overnight removal. The only complications among the successful extended wear patients were corneal staining (24%) and conjunctival injection (11% ). Both conditions were minor and required no definitive treatment other than either temporary lens removal, daily wear of lenses or lens replacements. Favourable results were attributed to a number of factors including examination and replacement of lenses every six months, practitioners' skill, lens material and design.

Extended wear (EW) lenses have been available in Sweden for over ten years and thousands of patients including Swedish Air Force pilots have been fitted successfully with these lenses (Nilsson, Rengstorff 1979). In a previous study of 19 patients who wore an EW lens on only one eye for an average of 5.4 years, there were no significant differences in refraction, keratometry, or visual acuity comparing the lens-wearing eye and the nonlens wearing eye (Rengstorff, Nilsson 1985). Factors which were attributed to these favourable results were the lens quality, extensive practitioner experience with extended wear lenses and patient management which emphasized regular aftercare, including lens replacements at least annually. EW lenses in the United States have been reported to cause significant complications which include corneal ulcers, giant papillary conjunctivitis, corneal infiltrates and endothelial changes (Adams et a11983, Spoor et al 1984, Cavanagh 1984, Weissman et al 1984, 1985, Aquavella et a11985, Molinari et a11985, Patrinely et al 1985). The purpose of this study was to review 2000 clinical records of patients fitted with contact lenses in order to determine the frequency of successful EW cases as well as the type and incidence of complications among these patients fitted under specific conditions. This retrospective study may also be useful in understanding the causes of more serious complications of hydrogel lenses which have been reported in other studies.

Tables 1A and 1B show the ages of patients when extended wear lenses were fitted and the distribution of refractive errors. About ten percent of these patients had previously worn hard or soft daily wear lenses fitted elsewhere. Table 1A. Ages of 2000 patients. Age at fitting No. 12 13 14 15 16 17 18 19 20 21 22 23 24 Total

%

18 1 24 1 38 2 82 4 218 11 280 14 331 17 272 14 249 12 203 10 146 7 85 4 54 3 2000 100%

Table lB. Refractive error of 2000 patients. Refractive Error (D)

Myopia Up to 1.00 1.00 to 1.75 2.00 to 2.75 3.00 to 3.75 4.00 to 4.75 5.00 to 5.75 6.00 to 6.75 7.00 to 7.75 8.00 to 10.50 Hyperopia 3.00 to 5.00

METHODS History. In Sweden health records are usually filed according to patients' date of birth. We reviewed records of patients born between 1959 and 1973 (ages 12 to 24 at time of initial examination) and analyzed the first 2000 records of patients who began to wear lenses on an extended basis. All records were obtained from a private clinical practice (KN) in Goteborg, Sweden.

Presented at the Annual Meeting of the American Academy of Optometry, St. Louis, Missouri, December 11, 1984. * Optometrist, PhD, FAAO. Abingdgon, Maryland, USA. + Optometrist, Goteborg, Sweden. t Research Assistant, Goteborg, Sweden. :~ Manufactured by Scanlens AB, Box 3098, Goteborg, Sweden.

(%) 2 19 24 22 15 9 4 2 2 1 100%

Lenses. All patients were fitted with Scanlens 751:, a high water content (71%) hydrophilic lens. The mate-

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Roy H. Regstorff et al

rial, a co-polymer of N-vinyl-2-pyrrolidone and methyl methacrylate has an oxygen permeability (Dk) of 36.0 × 10-11 (cm/sec) (ml O2/ml × mm Hg at 35C.) (Fatt, Morris 1977). The base curves ranged from 7.9 to 9. lmm in 0.2mm steps; diameters were 13.5, 14.0 and 14.5. Centre thickness ranged from 0.15 to 0.36mm.

Criteriafor successful E W. The primary determinants for successful EW included at least 14 days of uninterrupted lens wear, freedom from any significant complications, improvement in vision, comfort, convenience of lens wear and costs acceptable to the patient.

Fitting. All lenses were fitted "loose" to ensure at least

RESULTS Table 2 shows the number of successful EW cases according to the year lenses were fitted. Successful cases increased from 83% to 93% over the period 1975 to 1983. All these patients wore lenses at least 14 days before overnight removal; most patients wore lenses 30 or more days before removal and some wore lenses uninterrupted for more than 3 months.

3 to 4mm movement during the first few hours of lens wear. This was achieved in most cases with lenses having base curves of 8.5 or 8.7mm and diameter of 14.0mm. Lens movement became less as initial lacrimation decreased and some dehydration occurred after wearing the lenses.

Wearing Time. During the first week, patients wore lenses all waking hours and removed them each night. The purpose of daily wear was to familiarize the patient with lens insertion, removal, cleaning, overnight care and general adaptation to the lenses. After one week patients were asked if they preferred to wear lenses on a daily basis or begin extended wearing. If there were no contra-indications lenses were worn overnight and extended wear continued unless follow-up examinations indicated otherwise. Recommended wearing time was at least 14 days for all patients before cleaning and overnight removal. Examinations. After initial fitting, examinations were made following one week of daily wear, first overnight wearing of the lenses, at one week, two weeks, monthly for three months, and every six months thereafter. Each visit included a brief history regarding any discomfort or problems reported by the patient, visual acuity testing, over-refraction, slit-lamp examination of the lens movement and surface appearance as well as inspection of the cornea and bulbar conjunctiva. When indicated, by any patient discomfort, the palpebral conjunctiva was also examined. No qualitative or quantitive evaluation of the corneal endothelium was made in the routine care of these patients. Lens cleaning and asepticising. Cleaning of lenses was usually accomplished by using PR1, a Swedish product containing citric acid, although other commerically available soft lens cleaners were acceptable and often used. No enzymatic cleaners were recommended. Thermal units were used for overnight asepticizing of lenses until 1984 when hydrogen peroxide became the preferred method. Lens replacements. During the period 1975 to 1982, all patients were initially informed that lenses required replacement at least annually. Clinical observations during that time indicated that after six months of extended wear, about 50% of all patients had some degree of deposits on their lenses. For that reason, beginning in 1982, lens replacements were encouraged every six months. Patient compliance was excellent, estimated to be over ninety percent (Rengstorff 1983).

Table 2. Successful extended wear cases. Year 1975 (4 mos) 1976 1977 1978 1979 1980 1981 1982 1983 (3 mos) Total

Patients Fitted No. 23 165 195 2~6 350 360 292 317 82 2000

Successful No. %

EW Years

19 83 9 139 84 8 162 83 7 184 85 6 305 87 5 310 86 4 260 89 3 285 90 2 76 93 1 1740 87% (avg)

Table 3. Disposition of non-EW patients. Daily wear soft lenses 110 Daily wear hard lenses 26 Spectacles* 118 Total 254 *Unsuccessful with either soft or

5.5% 1.3% 5.9% 12.7% hard lenses

Table 3 shows the disposition of 254 patients (12.7 %) who did not wear lenses on an extended basis. Alternative treatments were usually decided in most cases within one month after initial fitting: 5.5% did not wish to continue wearing lenses overnight, instead decided to wear lenses on a daily or part-time basis. A small number of patients (1.3%) needed to be re-fitted with hard lenses: PMMA or gas-permeable lenses, usually because of residual astigmatism which could not be fully corrected with soft lenses. The remaining 118 patients (5.9 %) were unsuccessful with either hard or soft lenses. In these cases, it was the practitioners decision to discontinue treatment when symptoms of discomfort persisted or when patients demonstrated poor abilities to maintain adequate lens care. Table 4 shows the number of patients developing complications among the 1740 successful EW patients and the probable causes based on practitioners' examination, history and impressions at time of examination. Only two

Extended Wear Complications types of complications were noted: corneal staining with fluorescein, and conjunctival injection. The most common comeal staining was minimal, variable peripheral stippling or superficial punctate staining; no patient had deep corneal abrasions or any ulceration. Conjunctival injection appeared as mild congestion and dilation of the conjunctival vessels. All complications were reversible and usually associated with colds, illnesses., allergies, or unclean lenses. Treatment consisted of advising these patients to either discontinue wearing lenses for a few days, revert to daily wear or to replace lenses. No patients were observed to have giant papillary conjunctivitis, corneal infiltrates, neovascularization or any anterior ocular pathology.

Table 4. Extended wear complications and probable causes among 1740 successful E W patients. Complications: No. of patients Corneal staining with fluorescein 420 Conjunctival injection/"Red Eyes" 192 Total 612

Probable Causes of Complications: Associated with colds, illnesses Allergy, foreign bodies, solutions, unknown Unclean lenses, lens deposits Total

Percent 24% 11% 35%

281

46%

172 159 612

28% 26% 100%

DISCUSSION The type and incidence of complications among 1740 successful E W patients were minimal and not considered to be clinically significant. These results are remarkable when compared to other reports of more serious complications with E W hydrogel lenses. However, there were major differences between those reports and the study described here: most of the patients in this study were young, healthy college students carefully selected before being approved for extended wear; compliance was excellent including return for regular six month examinations; lens replacements were made whenever lenses appeared unsatisfactory, caused irritation, or a corneal/ conjunctival complication; lens replacements were made at least annually or every six months. The same patient management and treatment were not present in other reports of complications. It is therefore reasonable to conclude that the conditions in this study were important factors in minimizing complications. Clinical experience also confirms the likelihood of complications to increase whenever there is poor patient selection, compliance, management, lack of proper follow-up care and contaminated lenses. Our experience has shown that lenses with deposits or poor quality are direct causes of complications and lens replacement on a regular basis is

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absolutely essential for optimum eye health, comfort and vision (Rengstorff 1983). Another major consideration in minimizing complications is practitioner skill and experience in fitting extended wear lenses. For example, we learned in 1975 that when high water content lenses were fitted with little movement there was eventually an increase in the frequency of complications, e.g., fluorescein staining, red eyes, discomfort. Lens movement was therefore considered to be extremely important and initial fitting of these high water content lenses needed to be fitted "loose", because there was initial reflex lacrimation which later subsided as well as subsequent dehydration which caused lens tightening and less movement weeks or months later. It has been confirmed that a steepening of the lens base curve 0.3 to 0.5mm may occur with 10% lens hydration of high water content lenses (Refojo). The physical and chemical characteristics of the lenses, the process of manufacturing as well as lens design may also be factors to be considered in the successful results reported here. REFERENCES Adams CP, Cohen EJ, Laibson PR, Galentine P, Arentsen JJ. (1983) Corneal ulcers in patients with cosmetic extended-wear contact lenses, Am J Ophthalmol; 96:705-710. Aquavella JV, Rao GN, John R. (1985) Corneal ulcerationassociated with extended wear soft contact lenses. Geriatric Ophthal; June/ July:9-17. Cavahagh HD. (1984) Extended-wear contact lenses in aphakia: patient selectionand complications. TransNew OrleansAcad Ophthalmol: 67-74. Fatt I, MorrisJA. (1977) Oxygentransmissibilitychanges of gel contact lens during wear. Optician; 174:17-20. Molinari JF, Chaplan L. (1985) Serious complications of extended wear hydrogelcontact lenses: A review. The Contact Lens J (UK); 7:8-11. Nilsson KT, RengstorffRH. (1979) Continuous wearing of Duragel contactlensesby SwedishAir Forcepilots. A m J Optom Physiol Opt: 56:356-8. PatrinelyJR, WilhelmusKR, RubinJM, KeyJE. (1985)Bacterialkeratiffs associated with extended wear soft contact lenses. CLAO J; 11:234-236. Refojo,MF, Eye ResearchInstitute,Boston,MA (PersonalCommunication). Rengstorff RH. (1983) 6-Month Soft Lens Replacements. Optom Manag Nov: 43-47. RengstorffRH, NilssonKT. (1985) Long-termeffectsofextendedwear lenses: changesin refraction,cornealcurvature,and visualacuity.A n J Optom Physiol Opt; 62:66-68. Spoor TC, Hartel WC, Wynn P, Spoor DK. (1984) Complicationsof continuouswearsoftcontact lensesin a nonreferralpopulation.Arch Ophthalmol; 102:1312-1313. Weissman BA, Mondino BJ, Pettit TH, HofbauerJD. (1984) Corneal ulcersassociatedwithextended-wearsoft contact lenses.Am J Ophthalmol; 97:476-479. Weissman BA, Mondino BJ. (1985) Complicationsof extended wear contact lenses, lnt Eyecare; 1:230-234. AUTHOR'S ADDRESS Roy H. Rengstorff P.O. Box 333 Abingdon, Maryland 21009