`Irritation: Divide and Conquer
`
`Jeffery P. Gilbard, MD
`
`Patients with chronic eye irritation
`
`are probably some of the most
`time-consuming and vexing for
`the doctor. The good news is that a
`good history by an ophthalmic assistant
`who knqws what to ask can frequently
`make th~ diagnosis before the doctor
`steps into the room. In addition, there
`are now treatments that really work.
`Most patients presenting to the
`office witl1 chronic eye irritation will
`ultimately turn out to have either dry
`eye or blepharitis. Dry eye is caused by
`any condition that decreases tear pro(cid:173)
`duction or increases tear evaporation
`sufficiently to result in a loss of water
`from tl1e tear film and an increase in
`tear film osmolarity. Tear production
`can be decreased by lacrimal gland dis(cid:173)
`ease, as seen in Sjogren's syndrome, or
`by any condition that decreases corneal
`
`sensation. Included among the more
`common causes for decreased corneal
`sensation are laser in situ keratomileu(cid:173)
`sis (LASIK) and photorefractive kerate(cid:173)
`ctomy (PRK) procedures that interrupt
`or ablate corneal nerves, and long-term
`hard contact lens wear.
`Tear evaporation can be increased in
`the presence of hu·ge palpebral fissure
`
`Before discussing the
`patient history, it is
`important to understand
`that blepharitis can be
`divided into two major
`types: anterior and
`posterior.
`
`From the Schepens Eye Research Institute,
`the Department of
`Boston, Massachusetts;
`Ophthalmology, Harvard Medical School,
`Boston, Massachusetts; The Cornea & Vision
`Correction Center; Woburn, Massachusetts; and
`Advanced Vision Research,
`Inc., Woburn,
`Massachusetts. Portions of this article have been
`adapted from Gilbard JP: D1y Eye Disorders. In
`Albert DM, Jakobiec PA eels. Principles and
`Practice of Ophthalmology. Philadelphia: W.B.
`Saunders Company, 1994:257-276. Address cor(cid:173)
`respondence to Jeffrey P. Gilbard, MD, 7 Alfred
`Street, Suite 330, Woburn, Massachusetts 01801.
`Dr. Gilbard is Founder and CEO of Advanced
`Vision Research, Inc., (800) 979-8327.
`
`widths (i.e., over 10 mm) or from mei(cid:173)
`bomian gland dysfunction resulting
`from posterior blepharitis or meibomi(cid:173)
`tis (Figure 1 ). Increased tear film osmo(cid:173)
`larity, no matter what the cause, osmot(cid:173)
`ically dehydrates
`the eye surface,
`increases epithelial cell desquamation,
`decreases conjunctival goblet cell den(cid:173)
`sity, decreases corneal glycogen levels,
`and ultimately results in the loss of cell
`surface glycoproteins necessary for tear
`film stability. Conjunctival goblet cells
`
`are the mucous-producing cells on the
`eye surface that provide the natural
`lubrication for the eye; corneal glyco(cid:173)
`gen is the energy source for corneal
`healing.
`Before discussing the patient history
`it is important to understand that ble(cid:173)
`pharitis can be divided into two major
`types: anterior and posterior. Anterior
`blepharitis is less common and is char(cid:173)
`acterized by a dandruff-like process
`that occurs at the base of the lashes.
`This is different from the purulent
`drainage and crusting seen on the eye(cid:173)
`lashes in the still more uncommon type
`of anterior blepharitis caused by
`Staphlococcal aureus.
`Posterior blepharitis is the most fre(cid:173)
`quent type of blepharitis and involves
`an
`inflammatory process centered
`around the meibomian glands; this
`inflammatory process can spread
`throughout the lid margin and spill over
`to involve the ocular surface as well.
`Ultimately inflammation involving the
`meibomian gland leads to fibrosis,
`causing increasing disorganization and
`dysfunction of the meibomian glands.
`
`The Patient History
`A good history is one of the most
`powerful tools available to reach a
`diagnosis in a patient who complains
`of chronic eye irritation. There are
`seven questions
`that need
`to be
`answered to extract the most infonna(cid:173)
`tion from a patient.
`
`May/June 1999
`
`109
`
`APOTEX 1037, pg. 1
`
`
`
`plain of chronic sandy-gritty irritation (or
`buming) in their eyes, but in these pa(cid:173)
`tients the symptoms m·e worse upon
`awakening in the moming. This is be(cid:173)
`cause at night the inflamed eyelids are up
`against the cornea, tear secretion decreas(cid:173)
`es, and inflammatory mediators have all
`night to act on the surface of the eye.
`Since this is an inflammatory concli(cid:173)
`tion, patients also frequently complain
`of redness of their eyes in the morning.
`The symptoms m-e insidious in onset.
`Some patients may have discovered that
`hot compresses provide some relief.
`With time, meibomian gland inflam(cid:173)
`mation causes gland damage and meibo(cid:173)
`mian glm1d dysfunction develops. Tear
`film evaporation then increases, and
`these patients develop a second peak in
`their symptoms late in the day. Finally,
`after several years, the meibomian gland
`inflammation resolves as gland architec(cid:173)
`ture is destroyed and heals with fibrosis.
`These patients will then experience u
`resolution of their early morning symp(cid:173)
`toms but an intensification of their
`symptoms late in the clay.
`Occasionally patients with meibomi(cid:173)
`an gland dysfunction and orifice clo(cid:173)
`sure report that it feels as if their eyes
`ru·e tem-ing. It is important to note that
`these patients do not complain of tear
`overflow. How does closure of the mei(cid:173)
`bomian gland orifice and loss of the
`tear film lipid layer cause these symp(cid:173)
`toms? The lipid layer, in addition to
`decreasing tear film evaporation, also
`decreases the surface tension of the tear
`film, thereby holding the tear film tight
`to the globe. With loss of this lipid layer
`the tears splash around more, and the
`aqueous layer fi·om the tear iilm can
`begin to touch the mucocutaneous junc(cid:173)
`tion of the lid margin, especially with
`concomitant loss of lipid fi·om the lid
`margin as well. When this occurs it
`feels to the patient as if their eye is tear(cid:173)
`ing. (If tear ovetflow occurs, the exam(cid:173)
`iner will need to consider the diagnosis
`of nasolacrimal drainage dysfunction.)
`
`1. Character. What does the irrita(cid:173)
`tion feel like? Is it a sandy-gritty feel(cid:173)
`ing, burning, foreign body sensation, or
`increased "awareness" of the eyes? Do
`the eyes itch?
`2. Location. Where is the irritation
`located? Is it on the smface of the eye,
`in the eye, on the lid margin, or on the
`skin?
`3. Diurnal variation. Are the symp(cid:173)
`toms worse at any particular time of
`day? Patients typically have difficulty
`with this question. It helps to ask
`patients what symptoms are like upon
`awakening, at the breakfast table, at
`lunch and after dinner in the evening.
`Are they worse on awakening or late in
`the day? Are there two symptoms
`peaks-on awakening in the morning
`and then late in the day?
`4. Onset. Did the symptoms start
`suddenly, or did they develop gradual(cid:173)
`ly? Do symptoms occur in clearly
`delineated episodes or is this a continu(cid:173)
`ous problem?
`5. Duration. How long have the
`symptoms been present?
`6. Aggravating factors. Is there any(cid:173)
`thing that makes the symptoms worse(cid:173)
`wind, smoke, low humidity (i.e., air(cid:173)
`plane cabins), reading, watching TV,
`contact lens wear, artificial tears?
`7. Alleviating factors. Is there any(cid:173)
`thing that makes the symptoms better-
`
`hot compresses, eye closure, high
`humidity, artificial tears?
`Once this information is collected
`the examiner will have a constellation
`of symptoms that will match those
`associated with one or more of the con(cid:173)
`ditions detailed below.
`
`Dry Eye
`Patients with dry eye most com(cid:173)
`monly complain of a sandy-gritty feel(cid:173)
`ing in their eyes that becomes worse as
`the day progresses. This is because at
`night the closed eyelids form a water(cid:173)
`tight barrier completely blocking
`evaporation, and the eye surface has a
`chance to recover. With eye opening,
`evaporation begins, and as the day pro(cid:173)
`gresses evaporation pulls further and
`further ahead of tear production. For
`this reason, the symptoms increase as
`the day proceeds.
`The symptoms are insidious in onset,
`and initially patients may only complain
`of an increased awm·eness of their eyes.
`Late in the disease symptoms may be
`present throughout the day, but usually
`the diurnal variation persists. As the
`cornea becomes involved, patients
`develop sensitivity to light.
`
`Meibomltis and Meibomian
`Gland Dysfunction
`Patients with meibomitis also com-
`
`110
`
`May/June 1999
`
`APOTEX 1037, pg. 2
`
`
`
`Anterior Blepharitis
`These patients have symptoms at
`the anterior lid margin. Specifically,
`patients complain of crusting or irrita(cid:173)
`tion at the base of the lashes. The adja(cid:173)
`cent lid skin may be involved. Later in
`the disease there can be loss of lashes.
`There is no diurnal variation, and the
`onset is usually insidious.
`
`Large Palpebral Fissure Width
`The symptoms in these patients are
`nearly identical with those of patients
`with
`lacrimal
`gland
`disease.
`Sandy-gritty feelings and burning
`become worse as the day progresses.
`Because lacrimal gland function is
`normal- in these cases, patients can
`notice excess tearing.
`
`Decreased Corneal Sensation
`A history of fifth nerve trauma or
`surgery may be present. Recently,
`refractive corneal surgery has become
`a common cause of decreased corneal
`sensation. It is important to recognize,
`however, that there are many other
`causes for decreased corneal sensation,
`any one of which may play a role in the
`dry eye disease of a specific patient.
`Remember that any condition that
`decreases corneal sensation decreases
`tear secretion and may increase tear
`film osmolarity.
`One of the less frequently recog(cid:173)
`nized syndromes is the dry eye condi(cid:173)
`tion, associated with elevated tear film
`osmolarity, that may develop after
`long-term contact lens wear, particular(cid:173)
`ly long-term hard contact lens wear. 1•2
`Contact lens wear decreases corneal
`sensation, and the effect is more pro(cid:173)
`nounced with hard contact lenses and
`extended wear soft contact lenses.3.4
`The effect is cumulative, and it is not
`uncommon to see patients who have
`worn hard lenses for longer than 15
`years develop lens intolerance requir(cid:173)
`ing discontinuation of lens wear. Many
`of these patients complain of dryness
`
`and sandy-gritty feelings in their eyes
`that become worse as the day goes on
`even in the 'absence of contact lens
`wear. For this reason it is important to
`ask about contact lens wear in patients
`who complain of eye hritation.
`Once the contact lens history is posi(cid:173)
`tive, and if contact lens wear continues,
`it is important to determine whether
`
`Ocular irritation due at
`least in part to eye drop
`use should be suspected
`in all patients using
`traditional artificial tears
`more than 4 times a day.
`Both preserved and
`nonpreserved solutions
`can be responsible.
`
`there are any features of the contact lens
`cleaning and sterilization system (i.e.,
`.preservatives) or contact lens fit that
`may be contributing to ocular irritation.
`
`Medlcameneosa
`Ocular irritation due at least in part
`to eye drop use should be suspected in
`all patients using traditional artificial
`tears more than four times a day. These
`patients generally give a history of reg(cid:173)
`ular and frequently escalating eye drop
`use. Both preserved and nonpreserved
`solutions can be responsible, although
`there is now one commercially avail(cid:173)
`able preservative-free solution that
`appears to be free of this side effect.
`In these cases, complaints of sting(cid:173)
`ing with eye drop use should raise sus(cid:173)
`picions. Patients with medicamentosa
`characteristically
`are unable
`to
`describe a diurnal pattern to their
`symptoms-symptoms are equivalent
`
`throughout the day. This is because the
`damage is promoted by continued
`overuse of topical medications, even
`though use of these medications may
`temporarily mask symptoms by
`increasing the lubrication of the ocular
`surface.
`
`Lacrimal Drainage Obstruction
`The most likely basis for symptoms
`of tearing and tear overflow is lacrimal
`drainage obstruction. Some patients
`may complain of irritation of the skin
`at the lateral canthus rather than frank
`tearing. The skin here can become
`"chapped" from repeated exposure to
`tear fluid. Symptoms from lacrimal
`drainage obstruction are insidious in
`onset, and are usually exacerbated by
`exposure to wind and environmental
`initants.
`
`Allergic Conjunctivitis
`Patients with allergic conjunctivitis
`complain of ocular itching. They may
`also complain of increased mucus pro(cid:173)
`duction by the eye. The onset is com(cid:173)
`monly seasonal and may be associated
`with exacerbation of hay fever, asthma,
`or eczema.
`
`Nocturnal Lagophthalmos
`These patients commonly complain
`of burning in the eyes that is worse on
`awakening. There is frequency a histo(cid:173)
`ry of previous lid surgery or thyroid
`eye disease.
`
`Superior Limbic
`.
`Keratoconjunctivitis Sicca
`Patients with superior limbic kerato(cid:173)
`conjunctivitis (SLK) complain of burn(cid:173)
`ing and irritation and develop symp(cid:173)
`toms and remissions somewhat abrupt(cid:173)
`ly. A diurnal pattern to the symptoms is
`not usually evident. The factors initiat(cid:173)
`ing the development of exacerbations
`and remissions are not known.
`Episodes may last from months to
`years, and remissions may last for
`
`May/June 1999
`
`111
`
`APOTEX 1037, pg. 3
`
`
`
`MEIBOMIAN GLAND ORIFICES
`
`PATENT
`STENOSED
`CLOSED
`Figure 2. Chronic meibornitis lead to the development of meibomiarr gland dysfrmction. As the mei·
`bomiai1 gland dysfunction progresses, the meibornian gland orifice goes from patent, to stenosed,
`to closed.
`
`weeks or may be permanent. Vision is
`not affected. Females are affected more
`frequently than males, and it is com(cid:173)
`mon to see a history of thyroid dys(cid:173)
`function.
`
`Superficial Punctate
`Keratitis (Thygeson's)
`Thygeson's superficial punctate ker(cid:173)
`atitis is characterized by the insidious
`onset of photophobia, in·itation, and
`decreased vision. The course of the dis(cid:173)
`ease is episodic in nature and lasts
`about 2 to 3 'years. The cornea will
`show elevated punctate staining with
`fluorescein.
`
`Dry Eyelid Skin
`Some patients will say their "eyes"
`feel dry, but when questioned carefully
`reveal that they are referring to their
`eyelid skin. This common ambiguity
`underlines the need to determine the
`location of the symptoms. Frequently
`these patients will report the daily use
`of soap on the skin around their eyes.
`
`Tarsal Foreign Body
`Patients with a chronic foreign body
`sensation may have a tarsal foreign
`body. Symptoms are frequently monoc(cid:173)
`ular. In addition to exogenous material,
`a meibomian gland-derived conjuncti(cid:173)
`val concretion (or concretions) can
`
`the basis for symptoms that
`form
`remain enigmatic for years.
`
`Mucus Fishing Syndrome
`Some patients with ocular irritation
`develop the practice of reaching into
`their conjunctival cul-de-sac with their
`fingers and "fishing" out the mucus
`strand that they find there. These
`patients complain of eye irritation and
`increased mucus production by the eye.
`Conjunctival trauma induces an addi(cid:173)
`tional increase in mucus production and
`a vicious circle follows. Traumatized
`areas stain with rose Bengal,and the
`condition resolves once patient behav(cid:173)
`ior is altered.9
`
`Blepharospasm
`ble-
`primary
`Patients with
`pharospasm may complain of a "tired
`feeling" in the eyes that is actually their
`interpretation or description of their dif(cid:173)
`ficulty keeping their eyes open. On
`careful questioning it becomes apparent
`. that there is actually no eye irritation,
`but rather an involuntary closure of the
`eyes or an inability to keep their eyes
`open. Driving, reading and exposure to
`sunlight may exacerbate these symp(cid:173)
`toms. Since dry eye symptoms are com(cid:173)
`monly exacerbated by the same factors,
`it is very important to keep this fre(cid:173)
`quently missed diagnosis in mind.
`
`112
`
`,.,
`
`In patients with secondary ble(cid:173)
`pharospasm there is underlying chron(cid:173)
`ic eye irritation. Failure of the patient
`to respond to dry eye treatment may
`highlight the presence of this second
`condition.
`
`Nonspecific Ocular Irritation
`Not all ocular irritation is due to eye
`disease. The eye may be normal, and
`there may be environmental irritants,
`such as smoke and chemicals, responsi(cid:173)
`ble for symptoms.
`
`Nol'mal Eyes with Hypochondriasis
`This is a relatively uncommon prob(cid:173)
`lem. Usually ocular irritation is due to
`one or more of the entities previously
`mentioned. Nevertheless, it is important
`to recognize patients without organic
`disease, and sometimes a careful histo(cid:173)
`ry, which in turn fails to mesh with the
`examination, can provide the first clue.
`
`The Examination
`The two most common causes for
`chronic eye irr-itation are dry eye and
`meibomitis. The dry eye diagnosis can
`usually be made from the history, and
`the examination permits a determina(cid:173)
`tion of the cause or causes of dry eye
`in the patient. Signs of meibomitis can
`be very subtle and it helps to know
`exactly what the earliest signs are. The
`key elements in the examination of
`these two groups of patients are
`detailed below.
`Palpebral fissure width. Tear film
`evaporation is directly proportional to
`the distance between the upper lid and
`the lower lid. With the patient looking
`directly at the examiner's open eye,
`measure the distance between the upper
`lid and the lower lid.
`Once palpebral fissure width mea(cid:173)
`sures 10 mm or more, it becomes a sig(cid:173)
`nificant factor in increasing the evapo(cid:173)
`rative stress on the tear film.
`Meibomian gland orifice. As meibo(cid:173)
`mian gland function declines the mei-
`
`May/June 1999
`
`APOTEX 1037, pg. 4
`
`
`
`bomian gland orifice goes from patent
`to stenosed to closed (Figure 2). Patent
`orifices are visible on the lid margin.
`Stenosed orifices are not visible but
`when gentle pressure is applied to the
`lid, droplets of oil appear on the lid
`margin. Closed orificies also are not
`visible but here, when gentle pressure
`is applied to the lid, no oil appears on
`the margin.
`Lid margin. The normal lid margin
`· is free of visible blood vessels. The
`earliest change seen with meibomitis is
`the appearance of telangiectatic blood
`vessels on the lid margin.
`Tear volume and quality. The best
`way to examine the tear film is with
`fluorescein-not the drop from a bottle
`but with a wetted fluorescein strip. The
`problem with the drop from a bottle is
`that it replaces the tear film so the
`examiner is examining the drop rather
`than the tear film. Instead, take a fluo(cid:173)
`rescein strip, wet it with a drop of ster(cid:173)
`ile saline or irrigating solution, shake
`off the excess, pull the lower lid down,
`and paint the strip along the inferior
`tarsal conjunctiva.
`In cases where tear volume is
`decreased the fluorescein will not fluo(cid:173)
`ress under the cobalt blue light of the
`slit lamp, but instead remain dark. As
`tear volume decreases further, the tear
`film will assume a more viscous
`appearance-as the upper lid rises fol(cid:173)
`lowing a blink, the tear film, rather
`than snapping up quickly with it, will
`rise more slowly. Ultimately, patients
`with decreased volume develop debris
`in the tear film as well.
`In patients with meibomian gland
`dysfunction the tear film assumes a
`watery appem·ance due to a loss of the
`lipid layer. It will be apparent in these
`cases that the tear film is not lying tight
`to the globe.
`Ocular surface staining. In the
`presence of dry eye alone, whether the
`dye used is fluorescein, lissamine
`green or rose Bengal, the conjunctiva
`
`always stains more than the cornea.
`With posterior blepharitis alone, if
`there is any staining, the cornea always
`stains at least as much as the conjunc(cid:173)
`tiva. In both em·ly dry eye and mild
`blephm·itis, there may be no ocular
`surface staining at all.
`Corneal sensation. In patients with
`a history of contact lens wem·, corneal
`surgery, Trigeminal nerve damage, her(cid:173)
`pes simples or zoster, or diabetes, and
`with dry eye symptoms as well, it
`makes sense to test corneal sensation.
`This can be done easily with a cotton
`wisp. Wit11 experience the range of nor(cid:173)
`mal is easily appreciated.
`The history is the most sensitive
`indicator of dry eye, and these ele(cid:173)
`ments just detailed will enable the
`
`The two most common
`causes for chronic eye
`irritation are dry eye
`and meibomitis.
`The dry eye diagnosis
`can usually be made
`from the history.
`
`examiner to determine the cause of the
`dry eye symptoms. In the case of other
`causes for eye irritation, the history
`together with the careful examination
`of these elements, will narrow the dif(cid:173)
`ferential diagnosis and enable a defini(cid:173)
`tive diagnosis.
`
`Dry Eye Treatment
`It has been commonly taught that
`dry eye treatment begins with lubricat(cid:173)
`ing eye drops, also known as m"tificial
`tears. Attempting to treat dry eye
`patients with lubricant solutions is fre(cid:173)
`quently a
`frustrating experience.
`Dissatisfaction with the results of treat-
`
`ment has been attributed to the effect of
`preservatives or the short retention
`time of these drops in the eye. The tox(cid:173)
`icity of preservatives has been well
`documented.
`Until recently, the efficacy of tradi(cid:173)
`tional mtificial tem· solutions has been
`limited by an additional important
`mechanism. In order to understand this
`additional mechanism, it is necessm·y
`to review what is known about oph(cid:173)
`thalmic solutions and the electrolyte
`requirements of the surface of the eye.
`In 1960, Merrill and coworkers
`reported that 0.9% (isotonic) sodium
`chloride solution was toxic to conjunc(cid:173)
`tival epithelium in
`tissue culture.
`Solutions that had a more complete
`ionic composition did not show the
`same toxicity. 13 Nine yem·s later, in
`1969, Sussman and Friedman showed
`that frequent instillation of 0.9% sodi(cid:173)
`mn chloride solution in normal rabbit
`eyes led to eye redness and photopho(cid:173)
`bia and eventually to corneal epithelial
`breakdown. 8
`This work was lm·gely ignored until
`1985, when Bachman and Wilson stud(cid:173)
`ied desquamation from rabbit corneas.
`They found that corneal desquamation,
`or peeling, was increased with expo(cid:173)
`sure to 0.9% sodium chloride solution
`in compmison to a solution also con(cid:173)
`taining potassium, bicarbonate, calci(cid:173)
`um, magnesium, and phosphate. 14
`These data were later corroborated
`with morphologic studies. 15 In 1986,
`Fullard and Wilson demonstrated
`increased desquamation with a saline
`solution in vivo in human corneas
`using clinically relevant 30-second
`exposure times. 16
`
`Electrolyte Balance Crucial
`What emerges from this work is that
`the cornea and conjunctiva have elec(cid:173)
`trolyte requirements that are not met by
`solutions containing only sodium and
`chloride. Ultimately it was shown that
`the electrolyte requirements of the sur-
`
`May/June 1999
`
`113
`
`APOTEX 1037, pg. 5
`
`
`
`......... ~
`
`vated, continuing to osmotically pull
`water out of the surface of the eye even
`though the surface is wet.
`In order for an artificial tear solu(cid:173)
`tion to effectively lower elevated tear
`osmolarity, it needs an osmolarity of
`about 170 mOsm/L. 19 An eye drop
`with such osmolarity takes tear film
`osmolarity from about 330 mOsm/L in
`a dry eye to about 285 mOsm/L, and in
`doing so, flips the osmotic gradient
`between the tear film and eye surface
`so that water can move in to rehydrate
`the dehydrated tissues. A treatment
`called TheraTears (Advanced Vision
`Research, Woburn, MA) is this hypo(cid:173)
`tonic and has been shown, with QID
`dosing, to produce sustained lowering
`of elevated tear film osmolarity with
`continued treatment.20
`In addition, TheraTears precisely
`matches the electrolyte balance of the
`human tear film. 5•17•18 By lowering. ele(cid:173)
`vated tear film osmolarity and provid(cid:173)
`ing this electrolyte balance, TheraTears
`has been shown in pre-clinical studies
`to restore both conjunctival goblet cells
`and corneal glycogen levels in dry eye
`disease (Figure 3). More recently,
`TheraTears has been shown to cure
`symptoms and restore conjunctival
`goblet cells in dry eye patients follow(cid:173)
`ing LASIK.21
`A l)'eatment Program
`At the time of the initial visit,
`patients with dry eye can be started on
`TheraTears, 4 to 6 drops in each eye
`within a 5-minute period four times a
`day. The principle behind this closing
`interval is to facilitate rehydration of the
`tear film-ocular surface system in the
`dry eye patient.
`Patients with meibomian gland dys(cid:173)
`function are also instmcted to use hot
`compresses and lid massage to encour(cid:173)
`age e~pression of lipid into the tear film.
`The hot compress should be sho(cid:173)
`wer-temperat11l'e warm and applied to
`each eyelid for only about 5 seconds.
`
`Figure 3. Normal goblet cell dmsity (upper left) is decreased in dry eye (upper right). Treatment
`with TheraTears has been shown to restore conjunctival goblet cells (lower left), while treatment
`with traditional artificial tear solutions do not (lower right).
`
`face of the eye coincide with the unique
`electrolyte balance of the normal tear
`film. Specifically, the maintenance of
`normal conjunctival goblet cell density
`and corneal glycogen levels is depen(cid:173)
`dent upon the unique electrolyte bal(cid:173)
`ance of the tear film.
`Of key importance are the levels of
`sodium, chloride, potassium, and bicar(cid:173)
`bonate and, to a lesser extent, the pres(cid:173)
`ence of trace amounts of calcium, mag(cid:173)
`nesium, and phosphate.5•17•18 Without
`the proper electrolyte content and bal(cid:173)
`ance, a lubricating eye drop has the
`potential to cause both epithelial toxic(cid:173)
`ity and aggravation of goblet cell loss, a
`clinical syndrome known as medica(cid:173)
`mentosa.5·7 The electrolyte balance of a
`tear solution is crucial. Also crucial is
`the osmolarity of the tear solution.
`Since elevated tear film osmolarity
`causes the surface changes in dry eye
`
`disease, an artificial tear solution needs
`to lower elevated tear film osmolarity.
`
`The patient history is a
`powerful tool in
`narrowing the differential
`diagnosis of chronic eye
`irritation or even
`establishing the diagnosis.
`The examination adds
`power to the history.
`
`When an isotonic or even a weakly
`hypotonic eye drop is placed in a dry
`eye, tear film osmolarity remains ele-
`
`114
`
`May/June 1999
`
`APOTEX 1037, pg. 6
`
`
`
`Special attention should be paid to the
`lower lids.
`At the time of diagnosis, patients
`with meibomitis are started on doxycy(cid:173)
`cline 50 mg a day (or minocycline 100
`mg a day) along with the same hot
`compresses and lid massage regimen
`instituted for the meibomian gland dys(cid:173)
`function patients. The heat temporarily
`increases blood flow to the eyelid, and
`blood contains factors, such as a-2
`macroglobulin,
`that
`function
`to
`decrease inflammation.
`Patients are seen back in 4 weeks.
`Patients with dry eye are then divided
`into two groups: 1) improved and
`happy, and 2) improved but still unhap(cid:173)
`py. Those who are happy are continued
`on TheraTears, while silicone punctal
`plugs are inserted into the lower punc(cid:173)
`ta of patients who need a boost in
`effect. TheraTears are continued in all
`of these patients because of its unique
`ability to restore conjunctival goblet
`cells in dry eye disease.
`In patients with meibomitis the sys(cid:173)
`temic doxycycline is continued for 3
`months. At that time the patient's early
`morning symptoms are reevaluated. If
`they have resolved the dose is reduced
`in half. The dose is tapered this way
`every 3 months until the lowest, neces(cid:173)
`sary dose is determined or the doxycy(cid:173)
`cline can be stopped.
`
`Summary
`Dry eye and posterior blepharitis are
`the two most common causes for
`chronic eye irritation. Dry eye is caused
`by loss of water from the tear film
`resulting from either decreased tear
`production or increased tear film evap(cid:173)
`oration. The resultant increase in tear
`film osmolarity causes the changes on
`the eye surface responsible for the
`symptoms of dry eye. Posterior ble(cid:173)
`pharitis causes eye irritation from
`inflammation, and leads to the develop(cid:173)
`ment of meibomian gland dysfunction.
`The patient history is a powerful
`
`tool in narrowing the differential diag(cid:173)
`nosis of chronic eye initation or even
`establishing the diagnosis. The exam
`adds power to the history, and sorts out
`the mechanisms causing dry eye
`symptoms.
`The primary goal of dry eye treat(cid:173)
`ment is to lower elevated tear film
`osmolarity. This can be achieved with
`TheraTears treatment, either with or
`without punctal plugs. The primary
`goal of meibomitis treatment is to
`reduce inflammation. This can be
`achieved by hot compresses and lid
`massage and, when necessary, systemic
`treatment with low dose doxycycline.
`By determining the cause or causes
`of chronic eye irritation, effective treat(cid:173)
`ments can be employed.
`
`RIWERENCES
`
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`the
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`
`May/June 1999
`
`115
`
`APOTEX 1037, pg. 7
`
`