MSc in Clinical Optometry: Principles of Therapeutics (City University London) PDF

MSc in Clinical Optometry: Principles of Therapeutics Unit 5: Part 1 DISORDERS OF THE EYELIDS AND ORBIT Description: In this the first of three parts covering the management of common anterior eye disorders, conditions affecting the eyelids and orbit will be discussed. Hours: Eight Learning outcomes...

MSc in Clinical Optometry: Principles of Therapeutics Unit 5: Part 1 DISORDERS OF THE EYELIDS AND ORBIT Description: In this the first of three parts covering the management of common anterior eye disorders, conditions affecting the eyelids and orbit will be discussed. Hours: Eight Learning outcomes Following successful completion of this first part of Unit 5, you should be able to:  Differentially diagnose common disorders of the eyelids and orbit  Describe the pharmacological and non-pharmacological management of these conditions by the optometrist, including criteria for referral  Describe the ophthalmological management of those conditions requiring referral Introduction The ability to differentially diagnose common anterior segment disorders is an essential part of the day-to-day work of an optometrist. The development of the Additional Supply and Independent Prescribing specialities enables the optometrist not only to make a diagnosis but also to treat specific anterior eye diseases. This first part of Unit 5 will discuss the diagnosis and management of blepharitis, internal and external hordeolum, trichiasis, entropion, ectropion, pre-septal cellulitis, tumours and thyroid eye disease. The text should be read in conjunction with the College of Optometrists‘ Clinical Management Guidelines (CMGs) which can be found at: https://www.college-optometrists.org/guideance/clinical- management-guidelines.html Blepharitis the ciliary glands of Zeis. Symptoms of anterior blepharitis include ocular discomfort, soreness, burning, Blepharitis is characterised by inflammation of the eyelid itching and mild photophobia. Symptoms of dry eye may margins. The condition is often chronic and can be also be evident including blurred vision and contact lens difficult to manage because it tends to recur. The two intolerance. Alternatively, the patient may be main types of blepharitis are anterior and posterior asymptomatic. (although both may co-exist (mixed)) and they may also be referred to as anterior lid margin disease and posterior Signs of anterior blepharitis include aqueous tear lid margin disease respectively. Predisposing conditions deficiency, lid margin hyperaemia, lid margin swelling, include dry eye syndrome (present in 50% of people with crusting and desquamation around the eyelash follicles staphylococcal blepharitis and 25–40% of patients with (Figure 1) and madarosis (loss of lashes). Secondary seborrhoeic blepharitis), acne rosacea and seborrhoeic signs include inferior punctate epithelial erosion, dermatitis. marginal keratitis, and a mild papillary conjunctivitis. If the blepharitis is seborrhoeic in origin, oily or greasy deposits Anterior blepharitis will be evident on the lid margins and both the conjunctiva Anterior blepharitis is typically associated with: bacterial and lid margin will appear hyperaemic. Associated colonisation, usually staphylococcal, causing a direct seborrhoeic dermatitis is typified by oily skin and flaking infection; toxicity to staphylococcal exotoxins or an from the scalp or brows. allergic response to staphylococcal antigens. It may also be seborrhoeic in origin resulting from a disorder of 1 Disorders of the eyelids and orbit The tear film quickly becomes unstable. Patients present with crusting of the eyelids, irritation, burning, foreign body sensation, watering and photophobia, often worse in the morning. Examination of the lids reveals lid margin erythema and telangiectasia (dilated veins), rounding of the normally ‗square‘ posterior lid margin, foamy meibomian gland secretions, inferior corneal punctate keratitis, with a poor tear film and short tear break-up time. Patients with acne rosacea also have acneiform spots, especially around the nose (Figure 3), with facial flushing and erythema, telangiectasia and eventually rhinophyma (enlargement and thickening of the nose soft tissues). Accompanying meibomian gland abnormalities, there may also be marginal keratitis, in which small white Figure 1: Anterior blepharitis—crusting around infiltrates (white cell precipitates) are seen in the cornea, the eyelash follicle near the limbus (usually with some clear cornea between). These generally do not stain with fluorescein (main differential is microbial keratitis). Eyelash Posterior blepharitis abnormalities such as madarosis, poliosis (whitening of In posterior blepharitis (meibomian gland dysfunction), the lashes) and trichiasis (misdirection of lashes) are there is retention of the secretions of the meibomian often present in blepharitis (Figure 4). glands and blockage of the meibomian gland orifices (Figures 2a and b). Some of the pathology results from Complications of blepharitis include: bacterial colonisation of the eyelids, causing direct  Epiphora microbial invasion of tissues, immune-mediated damage,  Dry eyes or damage caused by the production of bacterial toxins,  Conjunctivitis waste products, and enzymes.  Chalazion formation  Trichiasis  Ectropion  Entropion  Corneal disease in the form of punctate epithelial erosions, marginal infiltrates, recurrent erosions, marginal ulcers, pannus, keratitis or interference with contact lens wear. Treatment regardless of type of blepharitis involves keeping the lids clean and free of crusts. Warm compresses 2 – 4 x daily (a clean flannel soaked in hot water held against the closed eyelids for five minutes) can melt the waxy plugs and allow the trapped lipid secretions to be released. Lid hygiene involves Figure 2a: Obstructed meibomian gland orifices (arrowed) Figure 2b: Obstructed meibomian gland orifices (arrowed) Figure 3: Acne rosacea 2 Disorders of the eyelids and orbit Staphylococcus aureus infection is implicated in many cases. Lid erythema and oedema accompany the localised swelling and may spread to involve most of the eyelid. The patient may also complain of epiphora. Severe cases may be associated with a pre-septal cellulitis. Occasionally, a secondary conjunctivitis may be present. An internal hordeolum may point both inwards towards the conjunctiva or outwards towards the skin, unlike an external hordeolum which always points towards the skin side of the lid margin (Figure 5). Staphylococcal blepharitis, diabetes and seborrhoea increase the risk of developing a hordeolum. Chalazia may occur following resolution of an internal hordeolum (or they may occur spontaneously). A chalazion Figure 4: Loss of lashes (madarosis), poliosis (P), represents a painless lump in the lid caused by blockage conjunctival scarring and shrinkage (S) and of meibomian gland ducts with retention of meibomian corneal scarring (Sc) secretions. The management of an external hordeolum is relatively cleaning of the lids with cotton buds or a clean flannel to straightforward. Most cases resolve spontaneously mechanically remove crusts, and some recommend without treatment, or discharge anteriorly onto the cleaning gland orifices with a surfactant such as dilute eyelash line. Hot compresses may aid the discharge of baby shampoo or solutions of bicarbonate of soda. the purulent material. Removal of the associated eyelash Dedicated lid cleaning solutions or wipes are also may aid resolution. Topical antibiotics (e.g. available. Cleaning should be carried out twice a day chloramphenicol) may be used for recurrent lesions and initially and reduced to once a day when symptoms have for those that are actively draining (to prevent bacterial improved. Cosmetics should be avoided. Lubricants for conjunctivitis). Consider referral to GP for systemic tear film abnormalities, and treatment of complications of antibiotics if: blepharitis such as dry eye, trichiasis and entropion give  the patient is pyrexial the patient symptomatic relief.  has tender preauricular lymph nodes  a pre-septal cellulitis is present. Topical antibiotics, oral antibiotics and topical steroids all have a place in the management of blepharitis. A topical Management of an internal hordeolum is much the same, antibiotic such as chloramphenicol should be used twice with most patients receiving a broad-spectrum topical daily, after deposit removal, if there is marked lid margin antibiotic during the acute inflammatory phase. If the infection. Ointments are generally preferred to eyedrops lump (in fact a chronic granulomatous reaction as they are in contact with the eyelid margins for longer. histologically) persists after the acute episode, it may Meibomian gland disease not adequately controlled by lid require incision and curettage under local anaesthetic. hygiene often responds to oral tetracyclines, particularly Because the majority of chalazia resolve spontaneously, in those cases associated with acne rosacea, but a patients should be reassured and only referred if there is prolonged course of three or six months is often required. no resolution over a period of months. Topical steroids are reserved for severe cases of blepharitis or for complications such as marginal keratitis. Blepharitis rarely goes away completely, and the most important advice to patients is that it is chronic, that it almost never causes serious visual loss or other problems, and that they may need to maintain a long- term eyelid hygiene routine, varying its intensity according to symptoms. Internal and external hordeolum A hordeolum (i.e. stye) is a localised infection or inflammation of the eyelid margin. An external hordeolum involves the eyelash follicle and associated glands of Zeis and Moll. It presents as a tender inflamed swelling of the lid margin. Occasionally, multiple abscesses may be evident involving the entire eyelid. An internal hordeolum involves the meibomian glands. It presents as a tender inflamed swelling within the tarsal plate and is more painful than a stye. Figure 5: Hordeolum or stye 3 Disorders of the eyelids and orbit Trichiasis  Horizontal lid laxity is a feature, resulting from Trichiasis is defined as a posterior misdirection of the atrophy of the tarsus and canthal tendons lashes towards the globe. This is different from (demonstrable on the snap back test in which the pseudotrichiasis, in which the lashes are directed central part of the lid is pulled downwards, and on posteriorly secondary to entropion. The primary causes release fails to ‘snap back‘onto the globe). of trichiasis are involutional (ageing) changes and scarring of the posterior lid lamella (superior or inferior). Cicatrical The condition may also be congenital. Several conditions  Scarring and contraction of conjunctival tissue, predispose a patient to developing trichiasis: which pulls the lid margin inwards toward the globe  Chronic lid margin disease (blepharitis)  Causes include: trauma, chemical burns, Stevens-  Epiblepharon (common in patients of Asian origin) Johnson syndrome, OCP, infections, or local  Past herpes zoster ophthalmicus infection response to topical medication  Trachoma  Eversion of the lids is difficult in cases of cicatricial entropion, unlike involutional in which eyelid tissues  Ocular cicatrical pemphigoid (OCP) are lax.  Stevens-Johnson syndrome  Vernal keratoconjunctivitis Spastic  Chemical burns  Results from ocular irritation The misdirected eyelashes cause conjunctival injection,  Causes include infection, inflammation or traumatic ocular irritation, pain and a foreign body sensation. (e.g. surgical) processes Examination may reveal tear film abnormalities, posterior  It usually resolves spontaneously once the cause lamellar scarring and involutional entropion. The cornea has been eliminated. may have corneal abrasions (punctate epitheliopathy), microbial keratitis and eventually scarring. Congenital  Very rare The management of trichiasis involves removal of the  Results from improper development of the lower lid offending lashes and then tackling any underlying retractor aponeurosis insertion into the lower border condition. Epilation removes the lashes, giving the of the tarsal plate patient symptomatic relief but may need to be repeated  This causes instability in the eyelid with consequent in 4-6 weeks. If due to entropion, the eyelid should be entropion. taped for temporary relief of symptoms. Other options include therapeutic contact lenses and ocular lubricants. Patients with entropion complain of excessive tearing,. irritation, redness and eye discomfort or pain. The Trachoma is caused by infection with the bacterium discomfort and pain are due to the effects of the lashes, Chlamydia trachomatis. It has an incubation period of five which often rub against the conjunctiva and cornea. to 12 days and begins slowly as conjunctivitis which leads Signs may include corneal and/or conjunctival epithelial to tarsal conjunctival scarring. The scarring distorts the disturbance from abrasion by the lashes and localised upper tarsal plate and leads to entropion and trichiasis. conjunctival hyperaemia. The eyelashes may turn in and rub against the cornea. This can cause eye ulcers, further scarring, visual loss, and even blindness. Trachoma is endemic in Africa, Asia Though the definitive treatment of entropion is surgical, and the Middle East, in areas of most poverty. Six million there is a place for medical management in those people worldwide are blind from trachoma. declining surgery, or awaiting treatment or referral. Ocular lubrication and tear supplements are helpful for protecting the ocular surface and also may break the Entropion cycle in patients with spastic entropion due to dry eye Entropion is the inversion of the eyelid with the lid margin syndrome. Keeping the lashes away from the corneal turned inwards toward the globe. It can be classified as surface will reduce irritation. This can be done by involutional, cicatricial, congenital or acute spastic. advising the patient to tape the lid to the skin of the cheek; other methods include epilation, a bandage contact lens, Involutional or even surgical tissue adhesive to a fold of skin just beneath the lower lid. These temporary measures may  Most common type give the patient some comfort.  Typically affects only the lower lid  Associated with ageing There are several surgical techniques, depending on the  More common in women than men degree and position of lid laxity, and they include: eyelid-  Patients with involutional entropion have smaller- everting sutures to pull the eyelid margin away (usually than-average tarsal plates for their ages temporary); removing a wedge of lower lid; tightening the canthal tendons or operating on the inferior lid retractors. 4 Disorders of the eyelids and orbit Ectropion Paralytic Ectropion is the outward rotation of the eyelid margin  Paralytic ectropion may occur with seventh nerve (usually lower). It occurs in approximately 4% of the palsy from diverse causes such as Bell‘s palsy, population over 50 and is bilateral in 50% of cases. cerebellopontine angle tumours, herpes zoster Without normal lid: globe apposition, corneal exposure, oticus (viral ear infection), and infiltrations or tearing, keratinisation of the palpebral conjunctiva and tumours of the parotid gland. visual loss may result. Other signs of ectropion include conjunctival hyperaemia and mucous discharge. Mechanical Ectropion often has a component of horizontal lid laxity. Individualised treatment is based on appropriate  Mechanical ectropion may occur with lid tumours, such as neurofibromas, that evert the lower lid. identification of the aetiology (see CMGs). Patients may have lid deformity for months or even years Ectropion may be congenital or acquired. Congenital before seeking medical attention. They often complain of cases are rare and usually involve the lower lid, irritated or red eyes with tearing. They may be constantly sometimes with associated congenital eye abnormalities wiping their eyes, exacerbating lid laxity and therefore the such as blepharophimosis, or microphthalmos. ectropion. Acquired types include: involutional, cicatrical, paralytic Mild cases may require no treatment and the patient may and mechanical. need to be advised that lid rubbing may increase lid laxity. Taping the lids closed at night or a therapeutic Involutional contact lens when there is a risk of corneal exposure may  Most common type and is related to ageing be helpful. Lubrication and glasses fitted with moisture  Ectropion results from structural lid changes, shields are also helpful if significant corneal exposure including: disinsertion of the lower lid retractors, exists. In some cases, taping the lateral canthal skin decreased tone of the pre-septal/pre-tarsal supero-temporally provides temporary relief, especially in orbicularis muscle in combination with medial/ patients with new-onset seventh nerve palsy. The correct lateral canthal tendon laxity (Figure 6). surgical treatment of ectropion depends on the aetiology, but often involves shortening of the lower lid and/or canthal plication (fold), under local anaesthetic. Pre-septal cellulitis Pre-septal cellulitis is a common infection of the eyelid and periorbital soft tissues characterised by acute eyelid erythema and oedema. It is a disease mainly affecting children, with 80% of patients under the age of ten and most under five. Patients may complain of fever/malaise and children may be irritable. Periorbital pre-septal cellulitis must be differentiated from orbital cellulitis, as the severity of the conditions and their treatments differ considerably. The orbital septum is a fibrous tissue layer arising from the periosteum of the superior and inferior orbital margins and inserts into the anterior aspect of the tarsal plates of the upper and lower eyelids (see Unit 1). The septum separates the superficial eyelid from the deeper orbital structures, and it forms a barrier that often prevents infection in the eyelid from extending into the orbit. Pre- septal cellulitis differs from orbital cellulitis in that it is confined to the soft tissues that are anterior to the orbital Figure 6: Involutional ectropion septum. Pre-septal cellulitis may spread posterior to the septum and progress to form subperiosteal and orbital abscesses. Upper respiratory tract infections, especially paranasal sinusitis, commonly precede pre-septal Cicatrical cellulitis. Causative organisms include Staphylococcus  Cicatricial ectropion occurs from scarring of the aureus, Staphylococcus epidermidis, Streptococcus anterior lamella of the lid by conditions such as species and anaerobes, all of which are common burns, trauma, or chronic dermatitis respiratory pathogens. Other causes include severe  Less common causes of cicatricial ectropion include acute hordeolum and skin laceration. tumours. 5 Disorders of the eyelids and orbit Patients with pre-septal cellulitis will present with an BCC is most common among those with light coloured acutely painful, swollen eyelid. They may also complain skin who have had significant sun exposure. The of blurred vision, conjunctivitis and tearing. When incidence of BCC increases with age, peaking in the examined carefully they have normal ocular motility, seventh decade of life, and other groups at risk include visual acuities and pupillary reactions. Proptosis is the immunocompromised, in particular patients who have absent. had many years of immunosuppression (e.g. anti- rejection drugs in transplant patients). Men are at Other causes of eyelid swelling such as insect bite, increased risk with a male-to-female ratio of 3:2. allergic reaction conjunctivitis, trauma, contact dermatitis and hordeolum need to be considered. There are three main types of BCC:  Nodular—appears as a small, translucent, raised Bacterial orbital cellulitis, which is an infection of the area with poorly defined edges, and is firm to the tissues posterior to the septum, is potentially more touch serious. The usual cause is spread of infection from an  Ulcerative—classic ulcerative presentation is a adjacent sinus, most commonly the ethmoid sinus, and nodular lesion that over time has developed patients may have a history of previous sinus problems telangiectasia (a reddish hue caused by persistent, or recent upper respiratory tract infection. Infection may and virtually permanent dilation of capillaries) along also spread from adjacent dacrocystitis, or trauma or the surface and an atrophied inner portion, creating surgery in the area. Pathogens include Haemophilus a "pearly," indurated outer margin with an excavated influenzae (children under five), Staphylococcus aureus, centre Streptococcus pneumoniae, and Beta haemolytic streptococci.  Morphoeic (sclerosing)—has a firm, pale, waxy yellow plaque with indistinct borders, which may Pain (particularly on eye movements), conjunctival spread just underneath the skin surface. chemosis, proptosis and ophthalmoplegia are the cardinal signs and symptoms of orbital cellulitis. The BCC, in the early stages, may present as a change in lid extra-ocular muscles may be restricted, visual acuity contour/redirection or loss of eyelashes and the texture reduced and pupil reactions may be abnormal (RAPD). of the surrounding skin may be lost. Occasionally, The symptoms may advance rapidly at an alarming rate secondary infection or inflammation may be evident. with the risk of loss of vision due to compression of the optic nerve by infected material. Affected children are Clearly, if a practitioner suspects BCC then referral with often systemically unwell with fever and malaise. details of location, size and history (documented with photography if possible) is required. This slow-growing Management involves confirmation of the diagnosis and neoplasm rarely metastasises but, if left untreated, could treatment of any predisposing conditions. Aggressive threaten sight (or life if it invades beyond the orbit). The systemic antibiotic therapy is used. most common treatment for lid BCCs is surgical removal. However, if the tumour is large, reconstructive surgery, Younger children or more severe cases are admitted for including skin grafting, may be required, thus intravenous antibiotics. In cases where improvement is emphasising the importance of early detection in its not prompt, further investigation with CT of the orbit and management. If surgical removal of the tumour is not an sinuses is indicated, and patients often end up having option, cryotherapy (freezing) or radiation therapy may be sinus surgery to drain pus. As complications can be used. Prognosis is good with early detection and severe, close monitoring is required. Therefore, any treatment; however, recurring BCC has a propensity to practitioner suspecting orbital cellulitis should refer the be aggressive and problematic to patient to a local eye or paediatric emergency unit. Patients with pre-septal cellulitis require urgent systemic antibiotics. Tumours Basal Cell Carcinoma Basal cell carcinoma (BCC) or rodent ulcer is the most common eyelid tumour, accounting for 80–90% of all cancerous lid lesions. It is slow growing, destructive and locally invasive and rarely metastasises. BCC may present as a non-healing ulcer with pearly white borders and ulcerated centre, and bleeding after minimal trauma. It usually presents on the lower eyelid (70%) (Figure 7), but is also found in descending order of frequency on the medial canthus, upper eyelid and lateral canthus. The basal layer, or the deepest layer of the skin, is thought to Figure 7: Basal cell carcinoma be the origin of the cancer, hence the name. 6 Disorders of the eyelids and orbit manage. Recurrence is rare. A 95% five-year cure rate cases,SCC may metastasise to regional lymph nodes. If exists for lesions less that 10mm. this occurs, the rate of morbidity and mortality rises exponentially. The diagnosis can only be confirmed after Squamous cell carcinoma biopsy or excision and microscopic analysis of the tissue. Squamous cell carcinoma (SCC) of the eyelids is rare, but may be a more aggressive malignancy than BCC. It The management of SCC of the eyelid is virtually is the second most common eyelid malignancy, identical to that of BCC of the lid. However, patients with accounting for 5% of all eyelid neoplasms. It is most often SCC must be thoroughly investigated to ensure there is encountered in elderly, fair-skinned individuals who have no metastasis of the disease. SCC may be treated with a history of chronic sun exposure, and occurs in surgical excision, radiation therapy, chemotherapy, or cryotherapy. The preferred course for most cases is association with other ultraviolet-related pre- cancerous lesions (e.g., actinic keratosis, Bowen dermatosis), in surgery, with broad margins to ensure complete removal. immunocompromised patients, in those with Frozen tissue sections of the tumour borders are considerable exposure to oils or tar, and patients with the evaluated intraoperatively to further assure that the lesion rare skin condition xeroderma pigmentosum. SCC can is excised completely (Mohs‘micrographic technique). develop even if the history of sun exposure occurred This method offers the greatest success with the least decades prior to development of the skin lesion. incidence of recurrence. After excision, patients should be observed for recurrence of previously excised malignancy or development of other epithelial eyelid tumours. Benign eyelid lesions Cysts can arise from any of the glands around the eyelid margin. Cysts of Moll are benign clear fluid-filled cysts occurring along the upper or lower lid margins. Cysts of Zeis derive from the small sebaceous glands associated with lash follicles; blockage of the latter leads to an accumulation of the yellow/white sebaceous material. Patients should be reassured that these cysts are benign and surgical removal (excision, cryotherapy) is only indicated for cosmetic reasons. Molluscum contagiosum is a benign skin lesion caused by the poxvirus. It is contagious and spreads through direct contact. Lesions can be single or multiple and characteristically consist of a dome-shaped, waxy Figure 8: Squamous cell carcinoma umbilicated nodule 2–3mm in diameter. They are generally asymptomatic, but continuous shedding of toxic The clinical presentation is very similar to the BCC viral products from such lesions can lead to a chronic (Figure 8). Patients presenting with this lesion may follicular conjunctivitis. Molluscum lesions are usually demonstrate a roughened scaly patch of tissue on or near self-limiting, but can be easily excised surgically. the lid margin or in the canthal region. The area is typically red, elevated and nodular, with crusted and/or bloody margins. Often, patients describe this lesion as ―a non-healing scab.‖ SCC in its early stages is easily Thyroid Eye Disease confused with a multitude of other eyelid lesions, both Thyroid eye disease (TED) most commonly presents in malignant and benign. Some of these lesions include th th women in their 4 to 6 decade, and is usually associated BCC, sebaceous gland carcinoma, follicular keratosis, with Graves‘ disease (autoimmune thyrotoxicosis), actinic keratosis, seborrheic keratosis, and although rarely it may precede the keratoacanthoma. thyrotoxicosis. As well as the systemic symptoms of an overactive thyroid (tremor, mood change/irritability, SCC is a potentially invasive tumour derived from surface weight loss, tachycardia), patients may present with epithelium. In the early stages, the normal epithelial cells ―staring‖ eyes due to proptosis (Figure 9), or lid are replaced by atypical squamous cells throughout the retraction and lid lag. They often complain of irritation due epidermis, resulting in a loss of normal maturation. This to corneal dryness and can be managed with lubricants. stage is sometimes referred to as SCC in situ. After the If there is considerable lid oedema and/or conjunctival dysplastic squamous cells encroach beyond the borders chemosis, advise patients to raise the head of the bed, of the basement membrane, the lesion is referred to as which may considerably reduce this. The serious invasive SCC. In advanced complication of optic nerve compression, which 7 Disorders of the eyelids and orbit diagnostic skills are essential. Once a diagnosis is made, an appropriate management plan can be established, which may include the prescription or supply of appropriate therapeutic drugs. This Unit should therefore be read in conjunction with Unit 4, which describes currently available therapeutic agents. Unit 5, Part 2 will concentrate on disorders of the cornea and lacrimal system. Acknowledgements and further reading Figure 9: Clinical signs of thyroid eye disease Bruce, A.S. and Loughman, M.S. (2012). Anterior Eye Disease and therapeutics A–Z. Butterworth-Heinemann, Second edition. occurs in less than 5% of patients with TED (and older, male patients are more at risk), presents with the signs of Gunduz, K. and Esmaeli, B. (2008). Diagnosis and optic neuropathy, such as reduced vision, reduced colour Management of Malignant Tumours of the Eyelid, vision and visual field loss. Practitioners should refer any Conjunctiva and Orbit. Expert Rev Ophthalmol 3(1) 63-75 suspect patient urgently. An important role for optometric practitioners is regarding patient education: TED is Hove, M. and Hammond C. (2005) Disorders of the associated with smoking, and patients should be eyelids, lacrimal system and orbit. Optician 5994 (229) informed of the connection and strongly advised to stop 29-35 smoking. Patients with significant proptosis, diplopia or eye symptoms not improved with topical treatment may McCulley, J.P. and Shine, W.E. (2003) Eyelid disorders: need hospital referral. the meibomian gland, blepharitis and contact lenses. Eye Contact Lens 29: S93-95 Conclusion This first part of Unit 5 presented an overview of diseases Kuriyan A. E., Phipps, R. P. and Feldonn, S. E. (2009) of the eyelids, lacrimal system and orbit. These range The eye and thyroid disease. Curr Opin Ophthalmol 19 from common non sight-threatening conditions that can (6): 499-506 be routinely managed by community optometrists to sight-threatening diseases, e.g. orbital cellulitis, that require urgent referral. Differential 8