Contact lens-related corneal ulcers requiring ... - Wiley Online Library

Acta Ophthalmologica Scandinavica 2006

Contact lens-related corneal ulcers requiring hospitalization: A 7-year retrospective study in Belgium Dominik Verhelst,1 Carina Koppen,1 Jan Van Looveren,1 Andre´ Meheus,2 Marie-Jose´ Tassignon1 and the Belgian Keratitis Study Group 1

Department of Ophthalmology, Antwerp University Hospital, Antwerp, Belgium Department of Epidemiology and Community Medicine, Antwerp University, Antwerp, Belgium

2

ABSTRACT. Purpose: To evaluate the clinical and epidemiological aspects of contact lensrelated infectious corneal ulcers requiring hospitalization. Methods: A retrospective analysis was performed on the files of patients hospitalized for contact lens-induced corneal ulcer in the eight Belgian university hospitals over a 7-year period (January 1997 to December 2003). Diagnoses for all hospitalized patients are obligatorily registered using the ICD-9 code. Results: A total of 107 patients with contact lens-related corneal ulcers were documented: the number increased from five in 1997 to 22 in 2003. A total of 99 subjects used soft contact lenses, of whom nine used disposables, 73 planned replacement and 17 conventional lenses. Only six patients used extended wear lenses. Three patients used daily disposable lenses. The most frequently cultured organisms were Pseudomonas and other Gram-negative germs (70%) and Acanthamoeba (16%). The majority (77%) of the corneal ulcerations were centrally located and resulted in an average visual loss of four lines. Conclusion: During the study period, the number of patients hospitalized rose, which is only partially explained by the increasing prevalence of lens wearers: 3.5% and 6.5% of the Belgian population used lenses in 1995 and 2003, respectively. These factual data highlight the need for improvements in patient education. Key words: corneal ulcer – contact lens – epidemiology – hospitalization – Belgium

Acta Ophthalmol. Scand. 2006: 84: 522–526 Copyright ª Acta Ophthalmol Scand 2006.

doi: 10.1111/j.1600-0420.2006.00681.x

Introduction Despite the growing success of refractive surgery, contact lenses remain an important option for the correction of refractive errors.

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Research into the development of new lens materials and care systems is ongoing; findings show that there is a marked tendency towards shorter renewal periods. Recent studies, however, have continued to report the

occurrence of complications in lens wearers, the most severe and visionthreatening of which is infectious keratitis (Derick et al. 1989; Nilsson & Montan 1994b; Cheng et al. 1999; Sweeney et al. 2003). Several surveys have been conducted to investigate potential risk factors, of which poor compliance and extended wear have emerged as the most important (Schein et al. 1989, 1994; Schein & Poggio 1990; Buehler et al. 1992; Liesegang 1997; Radford et al. 1998). In 1998, contact lenses became available in drug stores and supermarkets in Belgium. This led to concern among ophthalmologists that the incidence of contact lens complications would rise because the increased accessibility might lead the general public to perceive contact lenses as a commodity devoid of medical risks (Schlingemann & Nieuwendaal 2002). In order to confirm that the frequency of microbial keratitis due to contact lens use might be increasing, we decided to carry out a retrospective study on the clinical and epidemiological characteristics of patients hospitalized in the Belgian university hospitals for infectious corneal ulceration associated with contact lens use.


Results A total of 107 eyes were identified for analysis during the study period of 7 years. Patient ages ranged from 13 to 77 years (mean 28.8 ± 13.9 years). The female : male ratio was 1.5 : 1 (65 women, 42 men). Seventy-six patients had no relevant medical history, two suffered from chronic obstructive pulmonary disease, four had arterial hypertension, three diabetes mellitus, two thyroid gland pathology, 13 had an allergic constitution, two had chronic sinusitis. There was no mention of ocular allergy. In terms of ophthalmological history, three subjects had undergone penetrating keratoplasty and one patient had congenital glaucoma. One patient had undergone radial keratotomy 32 years previously, six patients were hyperopic and the other patients had myopia. Figure 1 shows the number of patients hospitalized for contact lens-

related ulcers during 1997–2003. The numbers increased over the course of the study period: five hospitalizations occurred in 1997, nine in 1998, 12 in 1999, 17 in 2000, and 22 in 2001, remaining at that level in 2002 and 2003. The distribution of hospitalized cases over the different university centres is shown in Fig. 2. A total of 99 patients were soft lens users with the following lens types and wear schedules: three used daily disposables (DW 1 day, although one of them admitted wearing the lenses for several days); six used weekly disposables (EW 1 week); 73 were on a frequent replacement schedule (DW 1 month, although five patients admitted sleeping with their lenses), and 17 used their (conventional) lenses for longer than 1 month (DW > 1 month). Eight of the hospitalized patients wore rigid gas-permeable lenses (DW), but none used polymethylmethacrylate lenses. The distribution of contact lensinduced keratitis in relation to lens type and wear schedule is shown in Table 1. Ulceration involved almost as many right (55) as left (52) eyes. A total of 82 of 107 (77%) of the hospitalized contact lens-related corneal ulcerations were central (i.e. in the pupillary area); the remaining 25 (23%) were peripheral. Microbiological cultures were performed in 101 cases: samples were taken from corneal scrapings or

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20 03

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0 19 97

A retrospective survey on patients hospitalized for corneal ulcers from 1997 through to 2003 was conducted in the eight Belgian university hospitals. We could only include hospitalized patients in our study: in Belgium it is obligatory to register the diagnosis for each hospitalized patient using ICD-9 codes, but this obligation does not extend to patients treated on an ambulatory basis. Based on ICD-9 codes, we were able to retrospectively trace the medical files of patients who had been hospitalized for corneal ulceration (codes 370.00–370.55). Because no coding for contact lenses had been used, a large number of files were generated and each of them had to be checked manually to see whether or not the ulceration was contact lensrelated. Only the records of ulcerations related to cosmetic contact lens wear were retained. The following data were collected from each chart: university centre; date of hospitalization; length of hospitalization; patient age and sex; residence; general and ophthalmological history; type of contact lens used; care system details; wearing schedule (daily wear [DW], extended wear [EW] or continuous wear [CW]); corneal localization of the ulcer; microbiological culture (from corneal scrapings, contact lenses, lens containers and ⁄ or contact lens fluids); type of infectious agent; visual outcome; residual injury, and whether or not the patient underwent surgery. Outpatient charts were consulted to determine visual acuity (VA) in the affected eye at the last visit and to obtain information on any surgical procedures. If data were incomplete, individuals were followed up by telephone inquiry. Information on the number of contact lens wearers in Belgium, with information on the profile of the lens wearers, was obtained through FADICON, the Federation of Contact Lens Producers and Distributors in Belgium (FADICON 2004, unpublished data). The data, generated through a street survey of voluntarily participating contact lens wearers, were based on a 44-item questionnaire addressing lens types and wear schedules. The demographics of contact lens wearers were compared with the composition

of the Belgian population, which was obtained from the Belgian National Institute of Statistics. By means of quota samples the population was divided into subgroups (gender and age) for the 10 different provinces. It was calculated in advance that a representative image of the population in Belgium would require data on a sample of at least 500 people. This quota was trebled because of the small numbers of people required in some provinces.

N Cases

Materials and Methods

Fig. 1. Number of patients hospitalized for contact lens-related ulcers during 1997–2003.

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8

Table 2. Results of bacteriological culture in hospitalized patients with contact lens-related corneal ulcers (n ¼ 101).

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Pathogen

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N cases

6 5 4 3 2 1 0 UZG (30)

UZL (27) CHUL (22) UZA (21)

VUB (3)

UCL (2) St Pierre (1) ULB (1)

UZG: Gent; UZL: Leuven; CHUL: Liège; UZA: Antwerpen; VUB: Brussel UCL: Brussel; St Pierre: Brussel; ULB: Brussel

1997

1998

1999

2000

2001

2002

2003

Fig. 2. Number of patients hospitalized for contact lens-related corneal ulcers at the different university hospitals.

conjunctival swabs, and from contact lenses, storage cases and ⁄ or contact lens fluids. Culture results were positive in 90 cases, including two cases of fungal keratitis and 16 Acanthamoebic infections. Cultures revealed mostly Gram-negative germs as causative agents (68.3%): Pseudomonas aeruginosa in 54 cases; Serratia marcescens in 16 cases, and Klebsiella oxytoca in 10 cases (Table 2). Hospital stays ranged from 2 to 71 days. The median duration was 7 days, the mean 9.4 ± 9.0 days. At the end of the study period all ulcers had healed and visual outcome was stable. In 80% of patients a residual injury remained. The final mean loss of VA was four lines (range 0–10 lines, median of four lines). Sixteen eyes underwent penetrating keratopl-

asty and one eye infected by Acanthamoeba had to be eviscerated.

Discussion In this retrospective study we describe 107 cases of contact lens-related corneal ulcers hospitalized over the past 7 years. As our cases included only patients hospitalized in the university centres, these numbers must be interpreted with caution. Firstly, contact lens-related corneal ulcerations managed on an outpatient basis are not included in our study, because there is no obligatory registration for these and relevant files are very difficult to trace. Secondly, the survey was limited to the tertiary patient care level in the academic centres: complications of this

Gram-negative bacteria Pseudomonas aeruginosa Serratia marcescens Klebsiella oxytoca Others Gram-positive bacteria Gram-positive cocci Parasite Acanthamoeba Fungi Candida albicans Negative culture Total cultures

68.3% 54 16 10 17 8.9% 9 15.8% 16 2.0% 2 11 10.9% 101

severity are most likely to be admitted to a hospital of this level and we were assured of a good level of co-operation in our efforts to obtain information on a well defined group of patients during the years studied. We know that our data exclude patients hospitalized for this pathology at other centres and patients managed on an outpatient basis, but we realized from the beginning that we would not be able to come up with incidence figures for infectious keratitis in the Belgian lens-wearing population for the reasons mentioned above. We aimed to determine if any changes in the incidence of this pathology in the Belgian university hospitals occurred in the 7 years under study. In fact, there was a rising trend in the number of hospitalizations, with admissions numbering five in 1997, steadily rising to 22 in 2001 and then plateauing at that level (Fig. 1). It is remarkable that 93.5% of all hospitalizations occurred at four of the

Table 1. Number of hospitalized contact lens-related ulcers by lens type and wear schedule.

1997 1998 1999 2000 2001 2002 2003 Total Total DW Total EW

Rigid gas-permeable DW >1 month

Soft conventional DW >1 month

Soft monthly DW1 month

Soft 2-weekly EW 1 week ⁄ DW 2 weeks

Soft weekly EW 1 week

Soft daily DW 1 day

Total

3 3 0 0 0 1 1 8 (7%) 8 0

2 2 2 3 5 3 0 17 (16%) 17 0

0 2 8 14 15 15 16 70 (65%) 65 5

0 0 1 0 1 0 1 3 (3%) 2 1

0 2 1 0 1 0 2 6 (6%) 0 6

0 0 0 0 0 1 2 3 (3%) 2 1

5 9 12 17 22 20 22 107 (100%) 94 13

DW ¼ daily wear; EW ¼ extended wear.

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eight university centres: Antwerp, Ghent, Leuven and Lie`ge. The four university hospitals of Brussels admitted only seven patients (6.5%) with contact lens-induced ulcerations during the period 1997–2003. We checked whether patients living in Brussels were treated in the other university hospitals: this was true for three patients treated and hospitalized at the university hospital of Leuven and one at Lie`ge. This finding of a markedly uneven distribution over the country of patients hospitalized for corneal ulceration might be explained by different policies of hospital admission. A steady increase in contact lens wearers has been noted over the past decade. In 1995, it was estimated that about 3.5% of the Belgian population used contact lenses (Socie´te´ Belge d’Economie et de Mathematique Appliqueés (SOBEMAP) 1995, unpublished data). A recent study by FADICON shows that the estimated number of contact lens wearers increased to 6.5% in 2003 (FADICON 2004, unpublished data). We can therefore assume that the number of contact lens wearers has almost doubled from 350 000 to 650 000. A total of 93% of Belgian contact lens wearers use soft contact lenses: the most popular of these are monthly renewal lenses (DW 1 month, 54%), followed by conventional soft lenses (DW > 1 month, 12%) and daily disposables (DW 1 day, 11%). Continuous or extended wear lens use (2%) is not as widely represented in the Belgian population. A total of 7% of lens

10%

2%

wearers use rigid gas-permeable lenses (DW > 1 month) (Fig. 3). Taking into account the limitations of our study, one might nevertheless argue that the number of contact lensrelated corneal ulcerations has increased more than might be expected from the increase in contact lens wearers. This trend seems to have evolved despite the success of planned replacement lenses in replacing conventional lenses, a general evolution that occurred in the 1990s. One might argue that 107 cases, spread across eight university hospitals over a 7-year period is a relatively low figure, but the fact remains that almost all these cases represent severe visionthreatening ulcerations. As described in the literature (Derick et al. 1989; Nilsson & Montan 1994a, 1994b; Cheng et al. 1999; Rattanatam et al. 2001; Sharma et al. 2003), the majority of patients were under 40 years of age and had no medical or ophthalmological history, apart from their refractive errors. Nilsson & Montan (1994a, 1994b) found a surprisingly good level of VA, due to the peripheral location of the lesions. We found the visual outcome to be much less favourable because of the central locations of the ulcerations: in 80% of all affected eyes this resulted in a mean loss of VA of four lines. Furthermore, 16 eyes underwent penetrating keratoplasty and one eye was eviscerated, which demonstrates the implications of this sight-threatening complication. An unexpected finding was the fact that three patients with daily dispo-

11%

soft daily soft monthly

4%

soft conventional 7%

rigid soft two-weekly soft three-monthly

12%

soft continuous 54%

Fig. 3. Type of contact lenses used in Belgium in percentages (Source: FADICON).

sable lenses developed a serious corneal ulcer. Two of the three cultures showed Pseudomonas aeruginosa. Although infectious keratitis in daily disposable soft contact lens wear should be highly unlikely, it has been reported in the literature (Buehler et al. 1992; Dejaco-Ruhswurm et al. 2001; Su et al. 2003). There is no need for lens cases or decontamination liquids with daily disposable lenses, so the reservoir for bacterial contamination of the cornea is eliminated; every day a perfectly clean and sterile lens is put on the eye straight out of its blister. However, it may be that the patient represents the weak point, because he or she does not use an optimal system correctly. We questioned the patients on their lens care practices and compliance with the wearing schedule: one patient wore the lenses for several days, even at night, and obviously had a compliance problem; the other two patients seemed to be compliant with the guidelines for contact lens wear. One might hypothesize that daily contact lenses, and in fact any lens, disturbs the physiology of the cornea, creating epithelial lesions and allowing bacteria to adhere to and invade the stroma. Newer silicohydrogel materials with higher oxygen permeability, now available as monthly and 2-weekly replacement lenses, might be the way forward for safer daily disposables. In conclusion, our study confirms that the problem of contact lens-related corneal ulcerations has not disappeared despite considerable technological advances in contact lens wear and care. In the literature, continuous wear and poor compliance (Schein et al. 1989; Schein & Poggio 1990; Buehler et al. 1992; Nilsson & Montan 1994a; Feys 2004) are referred to as the most relevant risk factors for infectious ulceration. Continuous wear is not popular in Belgium, due to negative experiences with this mode of contact lens and the high customer price of the new silicohydrogel lenses. Problems with compliance will always exist, however safe a system is made. As the daily disposable lens user in our study demonstrates, patient compliance remains a potentially weak point. Patients should be aware of the early signs of bacterial keratitis and the fact that they need to

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see a specialist who can prevent a serious outcome of microbial keratitis. Our data are not fully representative of this health problem in the Belgian population, but our study demonstrates the increasing importance of infectious complications caused by contact lenses. We want to stress that the fitting and wearing of contact lenses should be handled and followed-up by qualified personnel only (i.e. ophthalmologists or certified optometrists), who can counsel the wearer on the best available options and who can encourage patient compliance through regular follow-up.

Acknowledgements This research was supported by a grant from the Belgian Fund for Research in Ophthalmology. Thanks are extended to FADICON, the Federation of Contact Lens Producers and Distributors in Belgium, for supplying information drawn from its contact lens wearer study. The Belgian Keratitis Study Group comprises ophthalmologists R. Bourgeois, A. Zanen [Universite´ Libre de Bruxelles (ULB), Hoˆpital Erasme, Brussels]; I. Claerhout, P. Kestelyn (Ghent University Hospital); P. De Potter, E. Van Acker [Universite´ Catholique de Louvain (UCL), Hoˆpital Saint-Luc, Brussels]; B. Duchesne, A. Galand [Centre Hospitalier Universitaire (CHU) Lie`ge]; C. Koppen, MJ. Tassignon (Antwerp University Hospital); J. Libert, A. Stein (CHU Saint-Pierre, Brussels); E. Peetermans [Vrije Universiteit Brussel (VUB), Brussels]; W. Spileers (Leuven Univer-

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sity Hospital), and epidemiologist A. Meheus (Antwerp University).

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Received on March 30th, 2005. Accepted on January 17th, 2006. Correspondence: Dominik Verhelst MD Department of Ophthalmology Antwerp University Hospital Wilrijkstraat 10 BE-2650 Edegem Belgium Tel: + 32 3 821 3379 Fax: + 32 3 825 1926 Email: [email protected]