CET CONTINUING EDUCATION & TRAINING 1 CET POINT Recurrent corneal erosion syndrome 48 Rakesh Jayaswal MBChB, FRCS(ED), FRCOphth Recurrent corneal erosion syndrome (RCES) is a common clinical presentation. Understanding the condition and when to refer patients is paramount to a successful outcome. This article looks to explain the reasons for RCES and the challenges of patient management. The current treatment options are improving and varied, and the benefits of these new interventions will be explained. 06/06/14 CET Course code: C-36491 | Deadline: July 4, 2014 Learning objectives To be able to obtain relevant history when presented with cases of recurrent corneal erosion syndrome (Group 1.1.2) To be able to use appropriate slit lamp methods to recognise the signs of recurrent corneal erosion syndrome (Group 3.1.2) To be able to identify and manage cases of recurrent corneal erosion syndrome (Group 6.1.4) Learning objectives To be able to understand how different methods of slit lamp technique can be used to identify recurrent corneal erosion syndrome (Group 3.1.2) To be able to understand the management approach for recurrent corneal erosion syndrome (Group 8.1.3) Learning objectives To be able to understand the treatment and natural course of recurrent corneal erosion syndrome (Group 1.1.1) (Knowledge) syndrome (Group 1.1.1) To be able to assess cases of recurrent corneal erosion syndrome using appropriate techniques (Group 2.1.2) (Options) techniques (Group 2.1.2) About the author Rakesh Jayaswal is a consultant ophthalmologist, with specialist training in corneal and anterior segment disease. As the clinical lead for the NHS corneal service at Queen Alexandra Hospital, Portsmouth, and as founder and a medical director for LaserVision UK, Mr Jayaswal has considerable clinical experience and expertise in the management of corneal disorders including recurrent corneal erosion syndrome. optometrytoday CET IN ONE PLACE live bookshop CET Points for Optoms, DOs, CLOs and IPs www.optometry.co.uk/cet online enewsletter VRICS tv SE VEN CE T PO IN AVAILA TS BL ONLINE E NOW Introduction 49 Figure 1 Slit lamp appearance of active recurrent erosion showing ragged, oedematous, disrupted grey epithelium. Image courtesy of Peter R Laibson21 Figure 2 Broad-beam slit lamp appearance of anterior basement lines in RCES. Image courtesy of Peter R Liabson21 Pathophysiology inflamed mid-stromal keratocytes. Often the associated trauma that causes RCES originates from organic material such as fingernails or plant material, and the theory of a deposition of a proteinaceous material from such an injury may explain these findings. Another theory is based around abnormal expression of matrix metalloproteinase (MMP) – a generic name for a group of enzymes that can degrade part of the structure of the extracellular matrix. Gelatinase, composed of matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2), causes degradation of Type IV collagen, Type VII collagen and laminin – all major components of a basement membrane. The tears of patients with a history of traumatic corneal abrasions and RCE have been shown to increase MMP-9 and MMP-2 in affected and fellow eyes as compared with control eyes.5 Therefore, increased MMP-9 and MMP-2 expression have been implicated in the pathogenesis of RCES because the upregulation may lead to basement membrane degradation and poor epithelial basement membrane adhesion. The pathophysiology of RCES is only partially understood. Normal adhesions for the corneal epithelium depend on structures known as attachment complexes, which are composed of elements from the basal epithelial cell layer, basement membrane, Bowman’s layer and corneal stroma. Through electron microscopy and immunohistochemical staining methods, these elements are thought to include hemi-desmosomes, basal lamina, lamina densa, lamina lucida, anchoring fibrils, and Types IV and VII collagen. The presence of abnormal corneal epithelial basement membrane adherence to Bowman’s layer, whether by abnormal adhesion complexes or a reduplication of the basement membrane itself, is believed to be the underlying aetiology of recurrent corneal erosion syndrome. Recently, the Heidelberg Retina Tomograph Rostock Cornea Module (HRT II RCM) laser confocal microscope has been used to investigate pathologic changes in the epithelial-Bowman’s membrane adhesion complex. In patients with (ABMD) and a history of RCES, the HRT II RCM showed an abnormal epithelial basement membrane protruding forward into the corneal epithelium, the presence of epithelial microcysts and normal superficial epithelial cells and stroma.3 In contrast, when HRT II RCM examined patients with RCES due to traumatic corneal abrasions, the physiology of the corneal epithelium did not show these findings.4 The traumatic corneal erosion patients exhibited altered epithelial cells, activated keratocytes in shallow stroma and Diagnosis In patients with a history of previous trauma to the involved eye, episodes of pain on awakening, and epithelial microcysts, the diagnosis constitutes minimal clinical challenge. However, in more subtle cases, the diagnosis can be more difficult. After carefully inquiring about trauma to the affected eye, the clinician should undertake a detailed slit lamp examination to find subtle signs of RCES. Several different For the latest CET visit www.optometry.co.uk/cet 06/06/14 CET Recurrent corneal erosion syndrome (RCES) is commonly encountered in clinical practice and can be a painful, often frightening, and sometimes incapacitating condition for many patients. In this syndrome, as the name implies, corneal epithelial cells erode, resulting in denuded areas on the corneal surface. After re-epithelialisation, the process then recurs when the epithelial cells slough again at a later time. The erosions are typically episodic in nature, with many patients only having mild symptoms limited to a foreign body sensation or a vague awareness of the affected eye between erosions. These symptoms may be most noticeable in dry, cold or windy environments. Most erosions occur during the night or early morning hours and are often described as an abrupt ‘ripping’ or ‘tearing’ sensation, followed by an immediate sharp pain, foreign body sensation, epiphora, photophobia, reduced visual acuity and lid swelling. The attacks often vary greatly in pattern and intensity. Some patients have mild symptoms every few months or years and some experience severe, incapacitating, frequent erosions with symptoms lasting for a few days at a time. In a small subset of patients, the epithelial defects may never fully close, and loose sheets of epithelium slide over the surface of the eye with each blink. These patients experience constant pain and can be extremely distraught. The unpredictable nature of RCES often increases patient anxiety, as the knowledge of the sudden impact an episode can have on day-to-day life can be extremely disturbing. It is not uncommon for patients with RCES to demonstrate signs of depression and anxiety and some come to fear falling asleep or awakening, and experience varying degrees of insomnia. RCES often occurs due to superficial injury to the cornea, or may be caused by any one of the many ophthalmic or systemic diseases associated with it; these include anterior basement membrane corneal dystrophy (ABMD), such as Reiss Bucklers, lattice, macular, granular and Meesmann’s dystrophies; bullous keratopathy and diabetes mellitus.1,2 CET CONTINUING EDUCATION & TRAINING 1 CET POINT 06/06/14 CET 50 examination techniques can be helpful in this scenario. Broad, angled slit beam examination of both eyes before and after administration of fluorescein should be performed, as well as a retro-illumination examination of the cornea with a dilated pupil to discern the often subtle signs of basement membrane dystrophy or areas of previous erosion. Careful examination not only helps with diagnosis but also helps identify where to target treatment. Gentle pressure applied to the cornea via the eyelid may demonstrate wrinkling of any loose epithelium. A fine slit beam examination may reveal subtle granularity of the stroma, which persists after restoration of epithelial integrity (see Figures 1–3). However, in some patients, even with the most thorough examination, there may be a failure to identify any clinical signs. In such a situation, one should be wary of labelling these patients as functional or psychoneurotic, especially if they may be showing early signs of anxiety or depression. It is best to advise such patients to return for examination immediately if the episodic pain returns. Treatment For many years, RCES remained one of the more frustrating disorders to treat for both patients and the physician. Today, however, newer treatment modalities allow for a rationalised, stepwise approach to manage patients with RCES, often converting some of the most distraught individuals to the most grateful patients in clinical practice. Topical agents The initial approach to the medical management of RCES typically involves increasing the lubrication of the ocular surface and maximising the health of the tear film. A mainstay of medical treatment optometrytoday involves the long-term nightly use of hyperosmotic lubricating ointments. The rationale for this treatment stems from the concept of nocturnal relative hypotonicity of the tear film. At night, with the eyes closed, tear evaporation is reduced resulting in lowered concentration of dissolved salts in the tears. This shift in the osmotic gradients results in a relative increase in corneal epithelial oedema and consequent reduction in epithelial adhesion. The petrolatum vehicle serves to prevent erosions by keeping the eye lubricated during the rapid eye movements stage of sleep (REM) or while opening the eyes in the morning. Hyperosmotic eye drops during the daytime are sometimes added to this approach in an effort to minimise epithelial oedema during waking hours, thus allowing reformation of more normal attachment complexes. These agents must be used consistently for at least 12 months after the patient’s last erosion, since it often takes this much time for normal reformation. Unfortunately, patients frequently stop the use of these topical agents soon after the erosions resolve, only to have a recurrence, which may prolong the time required for the attachment complexes to reform. Currently available hyperosmotic ointments include sodium chloride 5% (Muro-128, Bausch & Lomb), and sulfacetamide 10% (Bleph-10, AK-Sulf ). Some investigators have suggested that topical corticosteroids combined with oral doxycycline may help treat recurrent erosions by the inhibition of MMP-9.6 As mentioned earlier, metalloproteinases are up-regulated in the tears of patients with RCES. As MMP-9 and MMP-2 can degrade Type IV, Type VII collagen and laminin, doxycycline and steroids, both metalloproteinase inhibitors, are commonly used in the treatment of RCES. In one recent study, patients with RCES unresponsive to traditional treatment, were CET IN ONE PLACE live bookshop CET Points for Optoms, DOs, CLOs and IPs www.optometry.co.uk/cet online enewsletter VRICS tv SE VEN CE T PO IN AVAILA TS BL ONLINE E NOW Figure 3 Slit lamp appearance of eye in Figure 2 with basement membrane lines enhanced using fluorescein. Image courtesy of Peter R Liabson21 placed on oral doxycycline 100mg twicedaily and fluoromethalone (FML) 0.1% four times daily to inhibit MMP-9.7. FML was chosen because of its poor penetration into the cornea, concentrating its effect in the epithelium. In corneal cultures, doxycycline produced a 70% reduction in metalloproteinase-9 activity.7 In addition to inhibiting MMP-9; doxycycline also improves meibomian gland dysfunction. A 70% shortterm relapse-free rate, improved subjective symptoms and a decreased recurrence rate over 21 months were reported.7-9 Patching and bandage lenses Bandage contact lenses may be used to treat acute erosions very effectively, but their use to prevent future erosions has mixed success. Silicone hydrogel lenses are often utilised, and patients are placed on topical antibiotic drops while an epithelial defect is present due to the increased risk of microbial keratitis.6,10 When used long-term, careful discussion about the risks and signs of infection must occur during consultation with the patient. Reflective learning Having completed this CET exam, consider whether you feel more confident in your clinical skills – how will you change the way you practice? How will you use this information to improve your work for patient benefit? For patients where medical management fails to resolve the erosions, several effective surgical options are available. The indication for surgical intervention is any situation in which medical management fails to improve the symptoms and signs of erosions, and when the patient’s continued pain and epithelial defects interfere with normal activities. The limited risks of surgical treatment for recalcitrant recurrent erosions generally override the threat of infection from erosions, in conjunction with the prospect of continued patient disability and pain. Debridement and superficial keratectomy Historically, debridement and then superficial keratectomy were the first surgical treatments for recurrent corneal erosions,11–13 and these procedures remain in use today.14 Debridement may be useful for removing a localised area of very loosely adherent epithelium in a limited number of erosion patients. This technique requires only a cotton swab and can be performed at the slit lamp with topical anaesthesia. The suboptimal efficacy and limitations of this procedure derive from the fact that no significant modifications to enhance epithelial adhesion are made in Bowman’s layer or other deeper corneal structures. Studies have shown a five-year cumulative probability of recurrence of 44.7%.15 Given the high recurrence rate with simple mechanical debridement, corneal surgeons will often undertake a procedure that will also treat Bowman’s layer to enhance adhesion. One approach is that of a large superficial epithelial keratectomy. Various surgical techniques have been described, with the aim of lifting the epithelium as a sheet while preserving Bowman’s layer. The use of a diamond burr to polish Bowman’s layer is thought to prevent RCES by both removing abnormal basement membrane and by causing a reactive fibrosis to allow scarring and stronger epithelial adhesion. This technique is more likely to be successful, with some studies showing a recurrence rate three times lower than simple debridement.16 More recently, a technique known as alcohol delamination has been proposed to improve the efficacy of debridement perforations with this technique, as well as questions regarding depth of penetration and the possibility of excessive scarring, disposable, specialist instrumentation was designed for Figure 4 Slide of human cadaver eye after stromal puncture. Image use in corneal 20 courtesy of Rubinfeld RS et al micropuncture.20 Anterior stromal puncture (ASP) attempts to improve in the treatment of recurrent erosions.17 epithelial adherence by inducing scar tissue Two recent articles investigated the to form between the epithelium and anterior use of alcohol delamination in patients stroma. Although ASP works relatively well in unresponsive to traditional therapy increasing irregular epithelium adherence, it (lubrication, cycloplegia, patching and 17,18 does create scarring (see Figure 5). Therefore, bandage contact lenses). Alcohol it is best used on patients with peripheral delamination involves epithelial removal pathology, most likely a post-traumatic RCE with a 20% alcohol solution in order patient. to re-establish a smooth Bowman’s Anterior stromal puncture is a procedure membrane surface. Dua et al showed performed at the slit lamp under topical that 66–83% of patients were symptom anaesthesia. When discussing this free after intervention, 75% of patients procedure with patients, the term epithelial became symptom free within one reinforcement may be substituted for stromal month of treatment and 91–100% of puncture, as the word ‘puncture’ can be patients had a favourable response in frightening for the patient. Treatment within the decrease of pain symptoms following 18 the pupillary space should be minimised if treatment. In addition, histopathological possible. Hyperosmotic ointments should examination of the epithelial sheets showed then consistently be used at bedtime for epithelial separation was at an interface 12 months after stromal puncture while overlying Bowman’s layer and included a attachment complexes and other ultraproteinaceous material that had replaced structural components are reforming to the anterior basement membrane (ABM). achieve maximal epithelial adhesion. The authors considered the proteinaceous A single anterior stromal puncture material probably represents a degraded procedure is effective in approximately 80% ABM from metalloproteinases or immature of selected recurrent erosion patients.21,22 basement membrane proteins, thus Treatment failure generally tends to occur interrupting cellular adhesions of the when the surgeon treats too small an area, basement membrane. and erosions then develop outside of the treated area. Anterior stromal puncture In 1986, McLean et al described a significant innovation in the surgical management of resistant corneal erosions, which they termed anterior stromal puncture.19 Initial methods involved the use of a straight 20-gauge needle to make multiple shallow penetrations through the epithelium into anterior corneal stroma (see Figure 4). Following several reports of corneal Excimer photo-therapeutic keratectomy Phototherapeutic keratectomy (PTK) using excimer laser technology involves treating Bowman’s layer, resulting in a modified, roughened surface to anchor the corneal epithelium.23 The patient’s epithelium is usually removed mechanically by debriding For the latest CET visit www.optometry.co.uk/cet 51 06/06/14 CET Surgical ‘options’ CET CONTINUING EDUCATION & TRAINING 1 CET POINT 06/06/14 CET 52 with a spatula or blade, or using an alcohol solution. Once the epithelium is removed, the laser is used to treat Bowman’s layer. As the excimer laser uses a flat treatment profile for standard PTK, the treatment usually results in a post-operative refractive shift towards hyperopia. By combining PTK with photo-refractive keratectomy (PRK), the treatment creates an opportunity to treat both RCES and refractive error in one procedure. Combining PTK and PRK can reduce or eliminate ametropia, improve the best-corrected vision by reducing the surface irregularity of the dystrophic epithelium, and resolve the recurrent corneal erosions. Despite questions regarding cost and refractive shift, excimer PTK is an important treatment for recurrent erosions, especially in patients whose corneal erosions are associated with marked basement membrane dystrophy. In addition, patients with corneal erosions caused by anterior corneal dystrophies, such as superficial variant of granular dystrophy and Reis-Bücklers’ dystrophy, may be excellent candidates for excimer PTK. Alternative ‘treatments’ Three case reports by a single ophthalmologist who treated RCES patients with botulinum toxin injections to the orbicularis muscle have been reported.24 All three patients had reduced RCE episodes but required multiple injections on several followup appointments to stay symptom free. The Conclusion Figure 5 Retro-illuminated slit lamp appearance immediately after anterior stromal puncture. Note that the area of anterior basement abnormality (box) extends beyond the limits of the treated erosive epithelium. Image reproduced from Rubinfeld RS et al27 author notes a study describing an ‘absent’ or ‘weak’ Bell’s phenomenon in patients with RCEs as compared to controls, and a 78% prevalence of abnormal Bell’s phenomenon in patients without a predisposing condition for their RCE in the same study.25 The proposed mechanism of improvement in RCE symptoms was a decreased effect of the orbicularis muscle during REM sleep in patients with an abnormal Bell’s phenomenon, limiting nocturnal erosions. Finally, an obscure treatment comes from the German literature, describing hypnosis for the treatment and prevention of RCES.26 The author describes a case study where he uses hypnosis and suggestions to treat a colleague with corneal erosion. The patient remained symptom free for 20 months. Although recurrent corneal erosion syndrome is a well-known disorder of the corneal epithelium, research concerning the aetiology and best treatment is ongoing. Prevailing practice trends seem to advocate medical treatment with topical lubrication, cycloplegia and antibiotic coverage or bandage contact lens for first time corneal abrasions. Long-term nocturnal lubrication is encouraged for patients with recurrent erosions. These patients are also treated with all efforts to maximise a healthy tear film, including oral doxycycline. When medical therapy fails, relatively simple surgical interventions may offer relief and improve quality of life for the patient. The decision as to which surgical correction is preferable will likely depend on surgical resources and surgeon experience. RCES can have a huge impact on the patient’s quality of life, so the threshold for surgical intervention is low. The recovery to being symptom free and a more routine sleep pattern is much faster with a relatively simple surgical procedure. However, despite the best medical and surgical efforts, RCES will recur in a subset of patients, frustrating both the doctor and the patient. When both parties understand the relapsing nature of this disease, the treatment process may become more acceptable to both. Exam questions References Under the enhanced CET rules of the GOC, MCQs for this exam appear online Visit www.optometry.co.uk/ at www.optometry.co.uk/cet/exams. Please complete online by midnight on clinical, click on the article title July 4, 2014. You will be unable to submit exams after this date. Answers will and then on ‘references’ be published on www.optometry.co.uk/cet/exam-archive and CET points will to download. be uploaded to the GOC every two weeks. You will then need to log into your CET portfolio by clicking on ‘MyGOC’ on the GOC website (www.optical.org) to confirm your points. optometrytoday CET IN ONE PLACE live bookshop CET Points for Optoms, DOs, CLOs and IPs www.optometry.co.uk/cet online enewsletter VRICS tv SE VEN CE T PO IN AVAILA TS BL ONLINE E NOW
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