Assessment Primary Eye Care

Transcription

1 Assessment Primary Eye Care Contact lens- induces peripheral ulcer (CLPU) Author: Jeroen Mulder E- mail: Student number: November 2013 Supervisor: Dr Michelle Hennelly

2 Table of Contents 1. Summary Background History and symptoms Investigation Most common differential diagnoses Corneal scar Contact lens- induced peripheral keratitis (CLPU) Adenoviral keratoconjunctivitis Herpes simplex keratitis Bacterial keratitis Management Discussion Microbial versus sterile keratitis Clinical severity Location and size Lens materials and care products Conclusion Learning points Reference list... 9

3 1. Summary Optometrists occupied in a contact lens practice often encounter corneal infiltrative events (CIE s). The practitioner relies on his own clinical experience and the relevant literature to differentiate between potentially sight- threatening microbial keratitis and an innocent self- limiting event. The subject in this case report is a young adult with mild complaints who visits me at the end of the day. I was ready to go home and left with one delicate question. Was this a simple and harmless contact lens- induced peripheral ulcer or was I dealing with a sight- threatening bacterial infection? Key findings in this case report are the clinical severity score and the location of the CIE; the more central the location, the greater the risk of a microbial keratitis. 2. Background In the Netherlands in 2010, the number of contact lens wearers was reported to be 1.7 million, accounting for 11% of the population (ANVC 2010). Various types of contact lenses have been introduced on to the Dutch market during the years. In the early years the largest majority wore rigid contact lenses or conventional soft (hydrogel) contact lenses, but over time this changed to disposable soft contact lenses. Disposable soft contact lenses were introduced with the expectation of minimising ocular surface infections. But CIE s still occur (Morgan, Efron et al. 2005). The optometrist in the first line is often the first contact for clients with CIE symptoms. It s the field of the optometrist to differentiate between a sterile or non- sterile event. But at which level can an optometrist manage a CIE and when is referral to the ophthalmologist indicated? 3. History and symptoms A 16- year old boy presented at Groenhof Optics and Optometry, Amstelveen, Netherlands with complains of a burning sensation and slight photophobia in the left eye for 5 days. He uses soft monthly disposable silicone contact lenses (CIBA vision AirOptix Aqua) on a daily base. 4. Investigation Best- corrected visual acuity (BCVA) was 20/20 in both eyes. Slit lamp examination showed mild hyperaemia and revealed a small, round, peripheral corneal infiltrate of approximately 1,5mm in diameter at 2 o clock in the left eye. Examination with fluorescein showed some staining on the infiltrate indicating a (small) epithelial break. No cells were present in the anterior chamber. The client was referred to the ophthalmologist the same day with the suspicion of a contact lens- related peripheral ulcer (CLPU). 5. Most common differential diagnoses 5.1 Corneal scar A healed (contact lens- related) peripheral ulcer can leave a scar at the peripheral cornea. Which is often seen during routine contact lens follow- ups. Most of these

4 lesions are asymptomatic. In these cases bio microscopy often shows no conjunctival hyperaemia and a flat epithelial round scar, without fluorescein staining. 5.2 Contact lens- induced peripheral keratitis (CLPU) CLPU is defined as a localized inflammatory reaction of the cornea. The active stage is characterised by focal excavation of the cornea epithelium, infiltration, and necrosis of the anterior stroma. Small (up to 2mm), single, circular focal infiltrates with slight diffuse infiltration surrounding the focal infiltrates can be found in the mid periphery to the periphery of the cornea (Sweeney, Jalbert et al. 2003). Symptoms are limbal redness and tearing. Patients usually experience severe to mild pain, foreign body sensation but could also be asymptomatic. 5.3 Adenoviral keratoconjunctivitis Keratoconjunctivitis is mostly caused by an adenovirus and one of the most common causes of acute conjunctivitis. The ocular symptoms are mainly sudden onset of irritation, soreness, red eye, photophobia and excessive tearing. The clinical features of the disease are conjunctival follicles, hyperaemia, chemosis and watery discharge. Typical corneal involvement ranges from diffuse fine, superficial keratitis to multiple sup- epithelial opacities. This can cause a decrease in vision and glare symptoms. 5.4 Herpes simplex keratitis The herpes simplex virus (HSV) is the most common cause of corneal blindness in the western world (Kanski, Bowling 2011). There are two subtypes HSV- 1 and HSV- 2. HSV- 1 typically causes infections above the waist like face, lips and eyes. Patients may complain about foreign body sensation, photophobia, redness, watering and blurred vision. The classic manifestation on the cornea is a linear branching corneal ulcer (dendritic ulcer) most frequent located centrally. This dendrite stains very well with fluorescein. 5.5 Bacterial keratitis Bacterial keratitis is a CIE caused by microorganisms. It s an inflammation of the cornea due to microbial agents like bacteria, fungi, protozoa and viruses. If not treated early or if it is not self- limiting it can be progressive and potentially devastating to the cornea resulting in blindness. Symptoms are foreign body sensation, pain, redness, excessive tearing, chemosis, eyelid swelling, purulent discharge and loss of vision. Clinical signs show epithelial defect associated with a larger defect, stromal oedema, folds in Descemet membrane and anterior uveitis. But in the early stage it can only present an epithelial defect and presents very similar to a innocent contact lens peripheral ulcer(morgan, Efron et al. 2010). Pseudomonas Pseudomonas species are generally considered to be the most virulent bacterial pathogen in contact lens related keratitis(fleiszig, Evans 2010). This bacterium does not adhere to the healthy cornea.

5 Protozoan keratitis Protozoa are a diverse group of single cell organism. The acanthamoeba is the only species of protozoa known to be associated with contact lens infections. Acanthamoeba species are widely distributed in our natural environment and are found almost everywhere like fresh water lakes, hot tubs, tap water, vegetables, contact lenses and even from the air we breathe(siddiqui, Khan 2012). The sequence of events in acanthamoeba keratitis involves breakdown of the epithelial barrier, invasion of the amoebae in the stroma, keratocyte depletion, huge inflammatory response and final stromal necrosis with devastating consequences for the clarity of the cornea. 6. Management The client was referred to the ophthalmology department of Ziekenhuis Amstelland, Amstelveen, the Netherlands with suspicion of a contact lens- induced peripheral ulcer (CLPU) the same day. After investigation by the ophthalmologist he was treated in his left eye with Tobramycine and Ofloxacine. The follow- up after five days still showed a trace of hyperaemia, but there was no staining visible with fluorescein and there were no cells in the anterior chamber. The nebula was still visible. The treatment with Tobramycine and Ofloxacine was continued for seven more days. The client was instructed to return to the hospital if the symptoms got worse and was told a small corneal scar could stay visible. The ophthalmologist wrote in the report to the general practitioner: small peripheral corneal ulcer 7. Discussion What does the literature say about an infection of the cornea? In the differential diagnoses ( 5) it s very difficult to find clinical differences between an early stage CIE and a early stage microbial keratitis. Let us solve the first half of the mystery: Every microbial keratitis is a CIE, but not all CIE s are microbial keratitis. So? Do we send all of our clients with CIE symptoms to the ophthalmologist so he can start (prophylactic) treatment with local antibiotics and steroids? Or are there any guidelines available to make it easier for the optometrist to differentiate? 7.1 Microbial versus sterile keratitis True confirmation of a microbial infection is dependent upon proof of the presence of a microbial organism, which can be found by scraping the cornea and culturing for evidence of pathogenic microorganisms. But studies like the Manchester keratitis Study(Morgan, Efron et al. 2005) and a survey of eight years laboratory experience(sharma, Kunimoto et al. 2002) report that, at approximately 50% of the cases when a corneal scrape is taken from a patient with clinical symptoms of microbial keratitis, the result turns out to be negative. These results are difficult to interpret: is there a true absent of microorganisms or are there microorganisms which are not collected during the scrape? If the scrape is positive, there is also a possibility the organism was part of the normal

6 ocular flora. This result was found in 10,3% of the occasions in the study of Sharma(Sharma, Kunimoto et al. 2002). 7.2 Clinical severity The Manchester keratitis study(efron, Morgan et al. 2005) used the criteria of Aasuri (Aasuri, Venkata et al. 2003) to determinate the clinical severity score. According to this scheme, CIE s with a clinical severity score greater than 8 could be considered as microbial keratitis and CIE s with severity score lower than 8 could be considered as sterile keratitis. See figure 1. Figure 1 Distribution of clinical severity scores for CIEs with respect to wearing modality and lens type. (Efron, Morgan et al. 2005) 7.3 Location and size In the Manchester keratitis study was found that the most of the CIE s were less then 2mm in diameter. A significant positive correlation was found between the distance of the infiltrate from the limbus and the clinical severity score. See figure 2. CIE s in the peripheral cornea are less clinically severe than those which occur in the central cornea. There was no significant relationship between distance of infiltrate from the limbus and the size of the infiltrate(efron, Morgan et al. 2005). Figure 2 Relation between the distance of the infiltrate from the limbus and the clinical severity score. (Efron, Morgan et al. 2005)

7 7.4 Lens materials and care products Extended wear (EW) has been a significant factor for CIE s in contact lens related studies for the past two decades. Stapleton reports a 16.9% greater risk for microbial keratitis when the contact lenses are also used overnight(stapleton, Keay et al. 2007). In a recent community based trail with 166 patients with symptomatic CIE s, younger patients were at increased risk of CIE s. Daily disposable lenses were protective relative to reusable lenses. There was in this study also a increased risk for EW and a silicone hydrogel increased risk in daily wearers regardless of the lens care product(chalmers, Keay et al. 2012). The increased rate of CIE s in silicon hydrogel wearers is perplexing, as we prescribe this material to avoid (hypoxic) complications, which we encountered in the past but also to minimize CIE s. This could be explained by the relative hydrophobicity of silicone hydrogel materials enhances bacterial adhesion. Kodjikian has shown that unworn silicone hydrogel lenses exhibit significantly greater bacterial adhesion in vitro than low Dk hydrogel lenses(kodjikian, Casoli- Bergeron et al. 2008). 7.5 Conclusion When encountering an early CIE in our contact lens practise it is very difficult to differentiate between a sterile and non- sterile infiltration. It is not possible to distinguish a low- grade early stage CIE from a beginning microbial keratitis. It has no use to perform a corneal scrape because we are not equipped and if we were there is a large chance the result could be falsely negative of falsely positive. It is more valuable to pay close attention to the clinical severity score this includes subjective and objective findings. Also, the more central the location of the CIE, the greater the risk of a microbial keratitis. Maybe we should stop using the term CLPU and name every ulcer on the cornea a corneal infiltrative event and monitor is very closely. The golden rule must be: if in doubt assume a microbial keratitis. EW causes a far greater risk to develop a CIE and should never be the first fitting choice in my opinion. And if people choose to wear EW always inform the client about a greater infection risk. 8. Learning points 1. Corneal scrapes I always thought corneal scraping was too difficult or too expensive to perform in a clinical setting. But the outcome of different studies show that corneal scrapes are often not reliable. 2. Greater risk with silicon hydrogel lenses worn on daily base This is a huge eye opener. I always explained to the client that changing from hydrogel to silicon hydrogel minimized the chance of an infection. But due to the hydrophobicity of silicone material the risk could even be higher. There is probably also a correlation between the condition of the tearfilm underneath a hydrogel and silicon hydrogel lens and the chance of an infection, but this assessment is too short to investigate this.

8 3. History In this assessment the history is a major part of the final diagnose. By listening very careful to the history and symptoms you can confirm your suspicions. This is also a key learning point during the Primary Eye Care module. History and symptoms gives you 85% clues and for the other 15% you use your clinical skills to confirm the diagnose.

9 9. Reference list AASURI, M.K., VENKATA, N. and KUMAR, V.M., Differential diagnosis of microbial keratitis and contact lens-induced peripheral ulcer. Eye & contact lens, 29(1 Suppl), pp. S60-2; discussion S83-4, S Weer nieuwe hoop voor nieuwe contactlensdragers, Available from: < [09/08, 2013]. CHALMERS, R.L., KEAY, L., MCNALLY, J. and KERN, J., Multicenter case-control study of the role of lens materials and care products on the development of corneal infiltrates. Optometry and vision science : official publication of the American Academy of Optometry, 89(3), pp EFRON, N., MORGAN, P.B., HILL, E.A., RAYNOR, M.K. and TULLO, A.B., The size, location, and clinical severity of corneal infiltrative events associated with contact lens wear. Optometry and vision science : official publication of the American Academy of Optometry, 82(6), pp FLEISZIG, S.M. and EVANS, D.J., Pathogenesis of contact lens-associated microbial keratitis. Optometry and vision science : official publication of the American Academy of Optometry, 87(4), pp KANSKI, J.J. and BOWLING, B., Clinical Ophthalmology: A Systematic Approach. Seventh edition edn. Elsevier Saunders. KODJIKIAN, L., CASOLI-BERGERON, E., MALET, F., JANIN-MANIFICAT, H., FRENEY, J., BURILLON, C., COLIN, J. and STEGHENS, J.P., Bacterial adhesion to conventional hydrogel and new silicone-hydrogel contact lens materials. Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie, 246(2), pp MORGAN, P.B., EFRON, N., HELLAND, M., ITOI, M., JONES, D., NICHOLS, J.J., VAN DER WORP, E. and WOODS, C.A., Demographics of international contact lens prescribing. Contact lens & anterior eye : the journal of the British Contact Lens Association, 33(1), pp MORGAN, P.B., EFRON, N., HILL, E.A., RAYNOR, M.K., WHITING, M.A. and TULLO, A.B., Incidence of keratitis of varying severity among contact lens wearers. The British journal of ophthalmology, 89(4), pp SHARMA, S., KUNIMOTO, D.Y., GOPINATHAN, U., ATHMANATHAN, S., GARG, P. and RAO, G.N., Evaluation of corneal scraping smear examination methods in the diagnosis of bacterial and fungal keratitis: a survey of eight years of laboratory experience. Cornea, 21(7), pp SIDDIQUI, R. and KHAN, N.A., Biology and pathogenesis of Acanthamoeba. Parasites & vectors, 5, pp STAPLETON, F., KEAY, L., JALBERT, I. and COLE, N., The epidemiology of contact lens related infiltrates. Optometry and vision science : official publication of the American Academy of Optometry, 84(4), pp

10 SWEENEY, D.F., JALBERT, I., COVEY, M., SANKARIDURG, P.R., VAJDIC, C., HOLDEN, B.A., SHARMA, S., RAMACHANDRAN, L., WILLCOX, M.D. and RAO, G.N., Clinical characterization of corneal infiltrative events observed with soft contact lens wear. Cornea, 22(5), pp