Ординатура / Офтальмология / Английские материалы / Clinical Ocular Pharmacology 5th edition_Bartlett, Jaanus_2008

problem, whereas tearing in an adult whose occupation involves exposure to noxious fumes is likely to be the result of ocular surface irritation and subsequent reflex tearing. Postmenopausal women are relatively deficient in both estrogens and androgens, which adversely affects the lacrimal functional unit, making this demographic group significantly more predisposed to dry eye disease. Infrequent blinking and palpebral fissure widening, with a resultant increase in ocular surface evaporation, have been linked to use of video display terminals. Certain medications like anticholinergic agents, antianxiety drugs, and antihistamines can decrease aqueous production and cause dry eye (see Chapter 35). Patients with obstructed drainage systems may have adapted to carrying a handkerchief or tissue to address the epiphora. A suggested protocol for obtaining a history from patients complaining of tearing is outlined in Box 24-2.

A sensitive and specific dry eye questionnaire is now widely used, either in its original or in a modified form, in

research and clinical settings (Box 24-2).A thorough interview for patients complaining of dry eye symptoms should include all elements addressed in the questionnaire.

Evaluation of the Secretory System

A wide array of testing procedures is available to assess lacrimal secretory function. There is significant controversy in the literature as to the reliability and repeatability of these tests.This dissension is reflected in the wide variability in practitioner opinion as to which tests are most clinically useful in the diagnosis of dry eye disease and related conditions. The standard of care currently stipulates that at least one objective measure of the lacrimal secretory system be used in addition to a comprehensive case history before a diagnosis is reached.The test selected is largely left to individual preference, but most practitioners frequently use ocular surface staining (sodium fluorescein

[NaFl], lissamine green, and/or rose bengal).

420 CHAPTER 24 Diseases of the Lacrimal System

2 mm

Horizontal part

Inferior meatus 20 mm

Figure 24-4 Cut-away view showing the lacrimal excretory system.Tears drain through the punctum (A) and eventually under the inferior turbinate bone of the nose. Dimensions of the canaliculi serve as references for probing and irrigation. B, canaliculus; C, common canaliculus. (Redrawn with permission from Jones LT. Ophthalmic anatomy: a manual with some clinical applications. I. The orbital adnexa. Am Acad Ophthalmol 1970:70.)

Examination of the Tear Film

It is often useful to grossly observe the patient before conducting a slit-lamp examination. A patient who is complaining of “constant watering” of the eyes but who

does not display any tearing during the case history or preliminary testing might require a different evaluation and management strategy than does the patient who presents with a box of tissues and frequently dabs excess tears while seated in the examination chair.

Biomicroscopy should include a quick inspection of the tear film and tear meniscus before the instillation of diagnostic drops or dyes.The test should look for appropriate quantity (the tear meniscus should occupy a height of at least 13⁄ mm above the lower lid margin) and quality (the tear film should be free of mucous strands, which often indicate an inadequate aqueous component;“frothing” and “oil slick” color fringes strongly suggest oil overproduction).There are two other common clinical tests available for measuring tear quantity: the Schirmer test, which has three subcomponents, and the phenol red thread test.

The Schirmer I, also called the standard Schirmer test or the Basal plus Basic Schirmer, involves the use of a paper filter strip that is bent and placed over the lower eyelid margin approximately one-third of the distance from the outer canthus. During the test the patient should be seated comfortably, away from direct drafts, in a moderately dim room.The patient should be instructed to blink normally but to keep his or her eyes open and in slight up-gaze during the test. Both eyes can be measured simultaneously. After 5 minutes the strips are gently removed, and the amount of tearing is assessed by measuring the linear distance of moistness on the strip. This zone of wetting may be more readily viewed by using filter paper strips that have been impregnated with a dye (Figure 24-6).There is some variation for interpreting this test, but it is generally agreed that less than 10 mm of wetting in 5 minutes is highly suggestive of aqueous deficiency, with less than 5 mm of wetting virtually confirming inadequate aqueous production. More than 15 mm of wetting is not diagnostic of a “normal” eye, however. No conclusions regarding lacrimal secretion can be drawn from a “normal” Schirmer I test, because both the reflex and the basic secretions are included, which is not representative of the patient’s natural state. In almost all cases further testing is pursued.

The Basic Secretion Schirmer test is performed in essentially the same way as the Schirmer I, with the

Box 24-1 Outline of Clinical Procedures for the Tearing Patient

History

Physical observation of excess tearing pattern, if present

Medial: obstruction Lateral: tear overproduction

Slit-lamp evaluation White light

Vital dye staining

Dye disappearance (clearance) test

Fluorescein should begin to clear the inferior cul-de- sac within 1 minute

Fluorescein should begin to appear in nasopharynx at this time

Drainage testing (Jones testing series) Fluorescein present: patent system

Fluorescein absent: obstructed drainage pathway (lacrimal lavage indicated)

important addition of a topical anesthetic to reduce or eliminate basal tear secretion to evaluate basic secretion alone. It is essential to carefully swab the cul-de-sac after anesthetic instillation to remove artificial “wetness” from the eye before conducting the test. Again, interpretation of results is variable, but less than 5 mm of wetting in 5 minutes is generally considered to be a relatively dependable indicator of aqueous deficiency.

The Schirmer II test can be performed in extremely dry eyes with very low results on Schirmer I. Before removing the paper strips at the conclusion of the Schirmer I test, a cotton swab is inserted into the nose to mechanically irritate the nasal mucosa. In normal subjects this stimulates an impressive basal tear secretion. If this response is present, ocular surface disease that has interfered with the normal neurologic feedback mechanism is suspected of contributing to the dry eye state. If the response is absent, lacrimal gland dysfunction is the likely cause.

The phenol red thread test is also a method to quantitatively evaluate aqueous tear production.This test is similar to the Schirmer test, but instead of a paper filter strip a thin thread is inserted into the lower cul-de-sac about one-third of the distance from the outer canthus. The small caliber of the thread diminishes basal tear contribution as compared with the Schirmer I test.A color change in the thread from yellow to red makes the visibility of the wet versus dry portions of the thread readily visible. Interpretation of this test is also the subject of some debate, but it is generally agreed that after 15 seconds less than 10 mm of wetting is abnormal, whereas 20 mm or greater indicates normal tear production. This test is done one eye at a time,because measurement is made in seconds versus minutes.

Box 24-2 Elements of the Case History for the Dry Eye Patient

Laterality (one eye or both?) Onset (gradual or acute?)

Course and frequency (progressive, intermittent, or stable? Seasonal?)

Duration

Severity

Factors relieving or exacerbating the symptoms Ocular and visual history

Contact lens use and history, including wearing schedule and solutions used

Prescription or over-the-counter remedies used for ocular or visual disorders

Prior ocular surgery (including refractive surgery and eyelid surgery) and trauma history

Chronic ocular surface disease (allergies, chemical burns, pemphigoid, trachoma, Stevens-Johnson syndrome)

Systemic health history

Full systems review including dry mouth, joint pain, atopy, skin rashes, etc.

Prior systemic surgery

Prior radiation in or around face/orbit Neurologic conditions

Menopause

Endocrine disorders (e.g., Graves’ disease) Chronic viral infections

Medication history Allergy history

Occupational or environmental exposures (social history)

Smoking

Lifestyle (outdoor activities, driving with windows down, etc.)

Family history—ocular or systemic disease

It should be noted that both the Schirmer and phenol red thread tests should be performed before the instillation of ophthalmic dyes. A summary of these tests and interpretation of the results is provided in Table 24-2.

Evaluation of the lipid layer has recently received much attention. There have been many methods and types of instrumentation proposed in the literature, including the use of videokeratography to detect lipidinduced reversible changes in corneal contour and a continuous functional visual acuity test to measure the effect of the lipid layer on functional vision. However, there is not as yet an easily accessible uniform method to assess the lipid layer of the tear film.

Measurement of the tear breakup time (TBUT) is one of the more common tests to evaluate the tear film (Figure 24-7).This test is most frequently done using NaFl and the cobalt filter on the slit lamp. Instability of the tear

Figure 24-6 Schirmer tear volume test strips. Strips are available with or without markings; some strips are impregnated with dye to allow easy visualization of wetting distance (top).

film is seen as a dark spot or “break” in the fluorescein tear fluid. Normally, patients have a TBUT of 10 seconds or longer with this technique; aTBUT of less than 5 seconds is highly suggestive of dry eye disease, with measurements between 5 and 10 seconds indicating an unstable tear film. This test can also be done noninvasively using the keratometer mires or other instrument requiring a smooth reflecting ocular surface. Noninvasive TBUT

times should be longer than TBUT using NaFl, with normal patients often having a noninvasive TBUT time of 30 seconds or longer. If this method is used, it should be done before the topical instillation of drugs or dyes.

THE FUNCTIONAL UNIT

Evaluation of the Ocular Surface

If NaFl stain is instilled for a TBUT measurement, it is a natural extension to then look for corneal and/or conjunctival staining. The presence of NaFl “staining,” rather than representing a true stain, indicates epithelial disruption, because the NaFl pools in areas of intercellular defects. Typically, the distribution of dry eye–related punctate epithelial keratopathy is in the lower third of the cornea and/or conjunctiva.

Adding rose bengal or lissamine green dye further enhances the diagnostic picture. Rose bengal stains dead and devitalized cells. The distribution pattern of rose bengal staining in dry eye is the same as that seen with NaFl but is observed with white light rather than the cobalt filter. Rose bengal also vividly stains mucous strands and filaments, which are prevalent in aqueous deficient dry eyes due to a lack of aqueous volume within which the mucus would ordinarily be dissolved. Rose bengal is available in liquid form, which is associated with significant ocular stinging upon instillation, and impregnated paper strips. Lissamine green, available on impregnated paper strips only, is offered as an alternative to rose bengal, because it appears to have similar staining properties but with less ocular stinging upon instillation. Both rose bengal and lissamine green staining properties are dose dependent, so it is important to instill a sufficient amount of these dyes for accurate ocular surface evaluation.

NaFl and rose bengal stains can be instilled simultaneously. Several grading scales for quantifying ocular staining with NaFl, rose bengal, and lissamine green have been

B

Figure 24-7 Tear breakup time test. (A) Immediately after several complete blinks, there is homogeneous tear film stained with sodium fluorescein. (B) Randomly formed dry spot signals conclusion of the test and indicates instability of the tear film.

proposed; use of such a scale in clinical research is critical to uniformly quantify clinical findings.

Another diagnostic strategy for evaluating the ocular surface in suspected dry eye syndrome is conjunctival impression cytology.With this method a strip of cellulose acetate filter paper is gently pressed against the bulbar or palpebral conjunctiva. After staining and preparation, the specimen is evaluated using a microscope. Conjunctival impression cytology is performed to detect morphologic alterations in the ocular surface, such as goblet cell density, structural changes within the epithelial cells, and the expression of inflammatory markers. These changes have been highly correlated with dry eye disease and are frequently used in clinical research as an objective measure of ocular surface changes. It is possible that conjunctival impression cytology will become more practical for routine clinical use in the future.

Evaluation of the Lacrimal Gland

The Schirmer II test can offer a preliminary functional assessment of lacrimal gland function. Gross inspection of the superior–lateral portion of the orbit may reveal prolapse of the gland, which may or may not adversely

Figure 24-8 Meibomian gland disease. Note “caps” or domes over meibomian orifices.These can be translucent, as in this case, or opaque, indicating a more severe solidification of meibomian secretions.

424 CHAPTER 24 Diseases of the Lacrimal System

Box 24-3 Evaluation of the Dry Eye Patient

Complete case history (see Box 24-2)

Observe patient outside of slit lamp (blink rate, tearing, lid abnormalities, level of discomfort displayed, etc.) Noninvasive TBUT (keratometer)

Slit-lamp examination: without dyes or anesthetic Observe tear meniscus height

Observe quality of tear film Evaluate integrity of ocular surface Evaluate lids, lashes

Observe and palpate lacrimal gland region Perform Schirmer test, if desired (note: instillation of

topical anesthetic will interfere with interpretation of TBUT)

Slit-lamp examination: instill NaFl Evaluate for ocular surface staining Measure TBUT

Slit-lamp examination: Instill rose bengal or lissamine green

Evaluate for ocular surface staining, mucous strands, etc.

affect lacrimal gland function or disclose swelling and/or masses within the lacrimal gland. Enlargement of the lacrimal gland causes a characteristic “S”-shaped deformity of the upper eyelid, regardless of the underlying cause of the enlargement (Figure 24-9). Imaging studies may be required in cases involving lacrimal gland abnormalities.

Evaluation of the Distribution System

Because the eyelids represent the distribution system for lacrimal fluids, their neural, muscular, and structural

Figure 24-9 Dacryoadenitis. Inflammation of the lacrimal gland is characterized by swelling of the superolateral eyelid and adnexal tissue and the diagnostic S curve of the upper eyelid. (Courtesy Michael A. Callahan, M.D.)

components must remain intact for proper maintenance of the tear film.The examination should note lid position, blink properties, and include a full evaluation of the lid margins and eyelashes.

DISORDERS OF THE SECRETORY AND DISTRIBUTION SYSTEMS

Disorders of the Lacrimal Gland

Dacryoadenitis is an inflammatory process of the lacrimal gland. Clinical characteristics include unilateral local tenderness, redness, eyelid swelling, conjunctival chemosis, discharge or suppuration, and enlarged preauricular nodes. Common causes include viral and bacterial infections, which generally produce an acute onset of symptoms, and systemic disorders such as sarcoidosis, tuberculosis, Graves’ ophthalmopathy, Mikulicz’s syndrome

(dacryoadenitis combined with parotid gland swelling), “sclerosing pseudotumors,” or Wegener’s granulomatosus, all of which more commonly present with a chronic disease course.

Persistent enlargement of the lacrimal gland requires differentiation between chronic dacryoadenitis and a lacrimal gland tumor (benign or malignant). Biopsy may be necessary when the episode does not follow the pattern for common causes of chronic dacryoadenitis. Neoplastic disease may present with or without pain or other inflammatory signs, so caution should be exercised in these cases.The presence of blood in the tears should heighten suspicion for lacrimal gland tumor formation.

Management

Acute dacryoadenitis usually responds rapidly to systemic corticosteroids. Patients with viral dacryoadenitis associated with acute epidemic parotitis (mumps), infectious mononucleosis, or herpes zoster infection should receive supportive therapy, such as rest, local application of ice, and use of oral analgesics, such as acetaminophen. Supportive therapy for mumps should be continued for its typical 2- to 4-week self-limiting course.

Bacterial dacryoadenitis should be treated with specific antibiotics after culture and sensitivity testing. Until results are obtained, many practitioners recommend an oral first-generation cephalosporin, such as cephalexin (Keflex, 500 mg four times a day for adults) or amoxicillin (250 to 500 mg three times a day for adults).This regimen should be followed for 7 days. Gonorrheal dacryoadenitis is treated with penicillin administered intramuscularly or with tetracycline taken orally.

Disorders of the Ocular Surface

Underlying ocular disease, such as allergic conjunctivitis, chronic infectious or inflammatory disease, or contact lens–related disorders, should be properly managed either before or as an adjunct to treatment of lacrimal

system disorders. Discussion of these diseases is covered elsewhere in Chapters 23, 25, 26, and 27.

Disorders of the Distribution System

The seventh cranial nerve is responsible for eyelid closure during the blink reflex. Partial or complete disturbance of cranial nerve VII can interrupt these impulses, resulting in incomplete lid closure. Loss of muscular tone can also lead to ectropion, disruption of the “lacrimal pump,” and ultimately impaired tear drainage.

The eyelid margins normally are smooth and regular. Inflammatory conditions and trauma can distort the lid margins, potentially disrupting the flow of the tear film. An inward-turning lid margin, with or without misdirected lashes (trichiasis), can disrupt the tear film dynamics or irritate the ocular surface causing punctate epithelial keratopathy and reflex tearing. Blepharitis and

MGD are frequently associated with ocular surface disease and tear film abnormalities; these disorders are covered in Chapter 23.

Dry Eye Syndrome

Dry eye syndrome, or keratoconjunctivitis sicca (KCS), was defined in 1993 and 1994 by the National Eye Institute Industry Workshop on Clinical Trials in Dry Eyes as “a disorder of the tear film because of tear deficiency or excessive tear evaporation which causes damage to the interpalpebral ocular surface and is associated with symptoms of ocular discomfort.” Based on this definition, the same workshop yielded a classification system for dry eye that includes two broad categories: evaporative dysfunction and aqueous deficiency. Each category has subgroups. This system is probably the most widely accepted paradigm. However, since this classification system was adopted, a much broader understanding of the inflammatory basis of most forms of dry eye disease has been achieved; further, new associations with dry eye have been recognized, such as refractive surgery. Despite these limitations the strategy continues to provide a reasonable means for classifying the disease and establishing a treatment plan.

Evaporative Dysfunction

Evaporative dysfunction is caused by a reduction in the lipid layer of the tear film. Most often, this condition is caused by MGD or blepharitis. MGD is traditionally conceptualized as a triad of meibomianitis (stagnated secretions within the meibomian glands), meibomian seborrhea

(overabundance of meibomian secretions into the tear film), and seborrheic blepharitis (oily debris visible on the eyelashes and ocular adnexal surfaces). Additionally, we have become increasingly aware of the influence of male hormones, or androgens, on the health of the meibomian glands. Clinically significant androgen deficiency, which naturally occurs in women of menopausal age and men in

their seventh decade and beyond, may lead to MGD, tear film instability, and ultimately in evaporative dry eye.

Several forms of blepharitis may cause evaporative dysfunction as well. Increased bacterial colonization of the eyelids causes breakdown of the lipids present on the surface of the tear film into free fatty acids; this in turn causes instability of the lipid layer.

Evaporative loss can also occur from abnormal ocular surface exposure, due to incomplete blink, nocturnal lagophthalmos, exophthalmos, proptosis, cranial nerve VII palsy, lid retraction, or other eyelid position and apposition disorders. Contact lenses may also contribute to an increased tear evaporation rate.

Management

To augment the dry eye therapies discussed below, MGD of the “standard” type is often managed using warm compresses, lid massage, and lid cleansing, with or without oral antiseborrheic agents (e.g., doxycycline 50 to 100 mg/day). In fact, warm compresses alone have been shown to have an immediate effect in thickening the lipid layer of the tear film. Blepharitis, both staphylococcal and seborrheic varieties, can be satisfactorily managed in many cases using lid hygiene with or without topical antibiotic ointment. Punctal occlusion, discussed below, serves to preserve the aqueous and the lipid layers of the tears. Androgen supplementation may prove to be a viable treatment for evaporative dry eye in the future.

Aqueous Deficiency

Aqueous-deficient dry eyes are subdivided into Sjögren’s syndrome (SS) and non-Sjögren’s syndrome (non-SS).

Sjögren’s Syndrome. SS is an autoimmune disorder characterized by the triad of dry eye, dry mouth (xerostomia), and a connective tissue disease.At least two components of the triad need to be present for the diagnosis of SS to be made. Primary SS, an exocrinopathy, is characterized by a lymphocytic infiltration and subsequent destruction of salivary and lacrimal glandular tissues. Symptoms include both dry eyes and dry mouth. Secondary SS includes dry eyes or xerostomia, plus a connective tissue disease, most frequently rheumatoid arthritis but also lupus, scleroderma, polyarteritis, or other related diseases. Unfortunately, there is no cure for SS at this time. Clinical trials using oral immunomodulatory agents have produced mixed results.

Non-Sjögren’s Syndrome. Non-SS KCS can be congenital or acquired.This category encompasses all other aqueous deficiency dry eye syndrome subtypes, including the “mucin-deficiency”dry eye, caused by damage to the goblet cells from disease, injury, or avitaminosis A.

Acquired non-SS KCS disorders are far more common than congenital forms. Although in the past it was believed that a significant difference between SS and nonSS KCS was the presence or absence of inflammation, it is

426 CHAPTER 24 Diseases of the Lacrimal System

now widely held that both SS and non-SS patients display inflammatory changes at the ocular surface and within the lacrimal gland, with associated alterations in the neural-sensory feedback communication system between these two structures. The main diagnostic distinction, it seems, is the presence of nonocular complaints resulting from the systemic autoimmune disease process in SS.

Lack of aqueous production at birth is a disorder termed congenital alacrima. This rare condition may result from hypoplasia of lacrimal gland tissue or congenital paralysis of cranial nerves. Another congenital and equally rare cause of aqueous deficiency is familial dysautonomia (Riley-Day syndrome), a disorder associated with a short life span.

Diagnosis

In addition to the evaluation protocols discussed previously to diagnose dry eye,it is important to probe for symptoms related to connective tissue disease. Simply inspecting the patient’s hands may yield a presumptive diagnosis of rheumatoid arthritis. A useful technique to screen for xerostomia is to listen for a “clicking” sound as the patient speaks, caused by inadequate saliva and poor oral lubrication. Alternatively, a tongue depressor may be placed on the patient’s tongue;the depressor often adheres to the surface of the tongue in patients with xerostomia.

Because of the thinned aqueous in SS and non-SS, lipidcontaminated mucous strands collect in the fornices. Patients may also complain of increased “mattering” associated with the presence of dried mucus at the nasal canthus on arising.The irritation accompanying the disorder, combined with excess mucus, may prompt the patient to manually attempt to remove the strands. The resulting mechanical irritation can cause further irritation and tearing.This vicious cycle, termed the mucous fishing syndrome, is characterized by rose bengal staining of mucous strands and the affected bulbar conjunctiva and cornea (Figure 24-10).

Figure 24-10 Mucous fishing syndrome. Rose bengal staining on the inferior bulbar conjunctiva instead of the expected interpalpebral location. (Courtesy Jimmy D. Bartlett, O.D.)

Management

Before directly treating dry eye, any comorbid conditions should be treated to the best extent possible. As previously mentioned, any associated ocular disease, such as blepharitis, MGD, ocular allergy, infections, and contact lens–related problems, should be appropriately addressed. Local or systemic disease, such as thyroid orbitopathy and orbital inflammatory pseudotumor, can cause exophthalmos and proptosis and should be comanaged with the patient’s primary care physician or appropriate specialist. Neuroimaging is often required to exclude orbital tumors in these cases.

Maximizing environmental conditions can have a significant impact in ameliorating symptoms. Some patients with an incomplete blink can be trained to make a full blink excursion. Redirecting air vents and fans, particularly ceiling fans, often brings symptoms to a manageable level.The use of humidifiers, particularly in dry climates, can be beneficial. Reminding patients to optimize their individual situations (e.g., drive with the car windows up, wear protective eyewear in dusty environments) is an important component of patient management.

Tear Supplementation. Tear substitutes, or artificial tears, have traditionally been the mainstay of treatment for dry eye syndrome. Artificial tears are often classified as low, medium, or high viscosity. Some artificial tears are supplied in single-dose units without preservation; other formulations offer a “disappearing” preservative that is neutralized before contacting the ocular surface.The elimination of potential effects from preservatives is desirable, particularly in highly sensitive patients. With a better understanding of the dynamics of the lipid layer of the tear film, artificial tear preparations have been developed that more closely approximate the bilayer of natural human tears.

For overnight use artificial tears are available in gel or ointment formulations. These products are much thicker than the high viscosity artificial tears and offer a prolonged ocular surface contact time. These formulations have the disadvantage of transiently blurring vision on instillation; patients should be informed of this effect and be advised to perform any visual tasks before instilling the gel or ointment. Gel formulations have the benefit of being water soluble, so removing any residue off the eyelids is more easily accomplished.

Tear supplements continue to be a rapidly evolving market.As many as 50 different over-the-counter artificial tears are available.These formulations are available either in unit-dose vials or in multidose bottle delivery systems and vary by consistency, active ingredients, and preservatives.Table 24-3 lists many of these preparations.

Tear Preservation. Occlusion of the lacrimal puncta, either temporarily or permanently, is one method of preserving tears that are available. Lacrimal plugs are available in diagnostic (dissolvable collagen) or reversible

Offers preservative-free formulation

(Refresh Plus) as well as special formulation for use with contact lenses; Refresh Tears is low viscosity; Celluvisc is high viscosity; Liquigel formulation is even thicker for longer lasting lubrication; Refresh PM is an ointment formulated for overnight use.

GenAqua is a disappearing preservative (sodium perborate); available in 0.2% drops (mild), 0.3% drops (moderate), and 0.3% gel (severe) formulations as well as 0.3% single-use preservative-free vials; contacts may be inserted 15 minutes after drop instillation.

Available as Tears Naturale Free (without preservative),Tears Naturale Polyquad II (low viscosity),Tears Naturale Forte (medium viscosity), and Tears Naturale PM (ointment).

Moderate viscosity; preservative-free single-use vials; contains zinc and bicarbonate to more closely match natural tears.

Low viscosity; formulated to match electrolytes found in human tears. Hypotonic. Drops and liquigel available in preservative-free vials;

drops also available with disappearing preservative in 0.5 ml bottle size.

Balances pH; forms a lubricating gel on contact with ocular surface and reported to reduce ocular inflammatory changes. Longer lasting formulation as compared with traditional formulations and can be dosed every 8 hours.

Restoryl augments lipid layer; milky white in appearance; patients should wait 10 minutes after drop instillation before inserting contact lenses. Dosed every 8 hours (more often if desired). Patient should “blink forcibly three times” after instillation to spread the drop.

Lipids within formulation cause drop to appear slightly milky; formulated to augment all three layers of tear film. Dosed two to four times a day.

(silicone) modalities (Figure 24-11).The collagen implants are useful as a trial for more permanent punctal occlusion. These plugs are inserted into the lacrimal puncta (either the lower puncta or both the upper and the lower puncta) and remain in place until they dissolve, which typically takes between 3 and 7 days but can be formulated to last approximately 1 month. If the patient experiences an improvement in symptoms during this time, with a subsequent exacerbation of symptoms after the implants dissolve and without experiencing epiphora during the trial period, it is fairly safe to assume that permanent (yet reversible) punctal occlusion is a reasonable option for that patient. Ocular surface

inflammation has been shown to improve with the use of punctual occlusion. Adverse effects of punctal plugs include potential infection within the canaliculus (canaliculitis) and spontaneous punctal plug extrusion (loss). Several varieties of reversible punctal plug devices are available. A summary of these devices is presented in Table 24-4.

Some practitioners prefer to occlude the puncta using laser or cautery. Although these methods do not present the same risk of infection, they are much more likely to result in spontaneous reopening of the puncta.

A more dramatic treatment to preserve the tears is lateral tarsorrhaphy, which is a joining of the lateral aspects

of the upper and lower eyelids.This procedure can be done with laser or by suturing and results in a smaller ocular surface area for the tears to cover.This treatment is considered a last resort, after other modalities have failed.

Tear Augmentation. Oral pilocarpine (Salagen) is available in 5- and 7.5-mg tablets taken three or four times daily to treat the dry mouth associated with SS.This drug

has the beneficial side effect of increasing lacrimation, making it especially useful for SS patients.

Flax seed oil has recently received much attention for its health benefits, primarily attributed to the high omega-3 fatty acid content. Omega-3 fatty acids have been shown to dampen the effects of omega-6 fatty acids through competitive inhibition; omega-6 fatty acids are linked to increased inflammation. It is believed that the overall effect of