Jane Goodwin BSc, MSc Nurse Practitioner

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Jane Goodwin BSc, MScNurse Practitioner

• Drugs and the Eye

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AP
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A P
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Pharmacology

• A solution is a liquid vehicle for drug delivery
  to the eye.
• Solutions have a shorter contact time.
• Drops drain into lacrimal apparatus, into the
  nose and are absorbed systemically.

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• Drops needs to be sterile therefore free from
  bacteria, viruses, and fungi.
• Preservatives are added to inhibit the
  multiplication of organisms.
• Some solutions oxidise when exposed to air which
  can alter their chemistry.
• The shelf life of drops are 1 month

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• Preservative free drops are supplied in single
• dose units Minims and used once

• Most eye solutions are expressed as per cent.
  This translate to grams / 100ml.
• EG 0.5 Chloramphenicol 500mg of
  Chloramphenicol in 100ml of solution.

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• Advantages of administering the drug locally is
  that is delivers the agent directly to the site
  of action.
• Its effects are more immediate.
• Smaller doses are used.
• Systemic side effects are minimised.

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Administration

• Locally direct into lower eye lid.

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Subconjunctival injection space between conj
and sclera
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Retrobulbar Injection - into muscle cone behind
the eye
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• Peripubulbar into space around the eye
• Intraocular into the eye eg Anterior Chamber

Intraocular Lens
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• Contact lens impregnated and placed on cornea

Edge of lens
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Absorption

• Drugs applied topically enter the eye through the
  cornea
• There are 5 layers to the
• Cornea

Descemets Membrane
Internal Layer Endothelium
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• The outer most layer have a high lipid content
  (lipophilic)
• The innermost layer have a high water content
  (Hydrophilic)
• Drugs therefore have to require both lipophilic
  and Hydrophilic properties
• PH of eye drops range between 3.5 10.5 which is
  to aid absorption
• Factors that can influence absorption include
  trauma to the cornea increasing the amount
  absorbed
• Drugs can also bind to contact lenses therefore
  reducing their effectiveness and cause damage to
  the contact lens

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Other factors affecting absorption

• Drops can be lost from the eye before they cross
  the cornea.

Occlude Inner Canthus
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Types

• Antibiotics
• Antihistamines
• Anti-virals
• Mydriatics dilation of pupil 2 types
  parasympatholytic Sympathomimetic
• Miotics constrict the pupil
• Glaucoma drugs -Carbonic anhydrase inhibitors,
  Beta-blockers, Alpha 2 agonists
• Steroids
• Local anaesthetics
• Diagnostic
• Tear Replacement

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Mydriatics- are used to dilate the pupil for the
following reasons

• To examine the retina
• To maintain dilatation of the pupil in uveitis,
  with corneal ulcers, severe corneal abrasions and
  after surgery
• To break down posterior synaechiae in uveitis
• To allow a cataract to be extracted and retinal
  surgery
• Refraction in children

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2 types

• Parasympatholytics which cause mydriasis and
  cycloplegia (relaxing circular iris muscle
  causing paralysis of the ciliary muscles)
• E.g. atropine, tropicamide and cyclopentolate
• Sympathomimetics - mydriasis (stimulating the
  radial muscle of the iris to contract causing the
  pupil to dilate)
• E.g. adrenaline and phenylephine

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Side Effects and Cautions

• Causes blurred vision therefore driving not
  advised
• Systemic absorption can occur causing
  anticholinergic effects such as tachycardia,
  dizziness, dry mouth, constipation and
  hypertension
• Due to risk of systemic absorption should be used
  with caution in people with hypertension, heart
  disease and thyrotoxicosis
• Can cause a rise in intra ocular pressure (IOP)
• Contraindicated in glaucoma especially narrow
  angle glaucoma
• Contra-indicated with MAOIs (monoamine oxidase
  inhibitors) risk of hypertensive crisis

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Miotics

• Miotic drugs constrict the pupil and ciliary
  muscle which opens up the drainage channel for
  aqueous flow. It main use is in the treatment of
  Acute Glaucoma
• Pilocarpine 1 2 and 4 (most common)

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Acute Glaucoma

• IS SIGHT THREATENING!
• Is a sudden rise in intra ocular pressure.
  This is caused by an acute blockage in the
  drainage system stopping the aqueous humour
  drain from the eye. Symptoms include a red
  painful eye, reduced vision, nausea, headache and
  can be in one or both eyes.

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Normal Flow
Acute blockage
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Miotics - Cautions

• Causes - Headache/browache in long term use..
  Usual burning itchy and sensitivity with drops.
• Blurred vision and restricted vision -
• Patient on long term treatment need monitoring
  for field s and IOPs.
• Avoid in conditions where a miosed pupil would be
  undesirable ie Iritis and Uvietis

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Chronic Open Glaucoma

• The angle is open but other parts of the
  drainage system can be affected.
• Slow onset, irreversible sight loss, hereditary,
  more common in elderly and Afro-Caribbean's
• Caused by a persistent low grade rise in
  intraocular pressures (normal readings are
  between10 - 21mmHg). Therefore readings above 22
  - 35 mmHg may require monitoring and treatment.
• It causes damage to the retinal nerve fibres
  known as cupping of the disc making the disc pale
  and a change in shape.

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Circulation of Aqueous
problem with aqueous drainage
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Other Glaucoma Drugs

• Carbonic anhydrase inhibitors
• Beta blockers
• Alpha 2 agonists
• Prostaglandin analogues
• Sympathomimetics
• Combinations of the above i.e. Carbonic anhydrase
  inhibitors and Beta blockers

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Carbonic anhydrase inhibitors

• Carbonic anhydrase is an enzyme necessary for the
  production of aqueous. These drugs therefore
  reduce the production of aqueous.
• Uses - Acute, Chronic and secondary Glaucoma
• Ocular SE Local eye irritation and taste
  disturbance
• Systemic SE drowsiness, GI, nausea, upset
  potassium levels and is a weak diuretic
• Types Oral and IV -Acetazolamide (Diamox) not
  used long term mostly in acute cases
• Examples - Topical Dorzolamide (Trusopt) and
  Brinzolamide (Azopt)

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Beta Blockers

• Are relatively safe, efficacious and usually
  first line treatment.
• Work by affecting the production of aqueous in
  the ciliary body and increase the outflow of
  aqueous in trabeculae meshwork
• Uses primary open angle glaucoma
• Ocular SE dry eyes, blurred vision, eye
  irritation
• Systemic SE bronchospasm in asthmatics,
  bradycardia and can mask manifestations of
  hypoglycaemia
• Examples Timolol (Timoptil), Betaxolol
  (Betoptic), Carteolol (Teoptic) and Levobunolol
  (Betagan).

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Alpha 2 Agonists

• Is used as add on therapy when beta blockers are
  not enough to reduce IOP or when Bblockers are
  contra-indicated.
• Works by enhancing drainage from the eye and
  decreasing production of aqueous.
• Uses primary open angle glaucoma and pre op
• Ocular SE dry eyes, blurred vision, eye
  irritation and stinging
• Systemic SE Headache, changes in heart rate,
  rhythm an BP as well as anxiety and tremor
• Examples Apraclonidine (Iopidine) and
  Brimonidine (Alphagan)

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Prostaglandin Analogues

• Work by increasing uveoscleral outflow
• Uses open angle glaucoma and ocular
  hypertension
• Ocular SE brown colour changes in the iris and
  lengthening of the eyelashes
• Examples Bimatoprost (Lumigan) and Latanoprost
  (Xalatan)
• NB ocular hypertension is when the IOP is
  normal but there is signs of the disease from the
  visual field tests and optic disc defects.

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Sympathomimetics

• Dipivefrine is a pro drug of adrenaline. It is
  claimed to pass more rapidly than adrenaline
  through the cornea and is then converted to the
  active form.
• Works by increasing the outflow of aqueous
  through the trabecular meshwork.
• It is contra indicated in angle closure glaucoma
  because it is a mydriatic (dilating drug)
• Ocular SE severe smarting and stinging
• Systemic SE caution with pts with hypertension
  and heart disease.

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Tunnel Vision
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Coffee Time !
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Microbiology of the eye

• Micro-organisms can gain access as a result of-
• Direct Contact e.g. Herpes simplex
• Air-Bourne infections
• Insect-Bourne infections e.g. Trachoma
• Migration of bacteria from nasopharynx
• Trauma
• Infected contact lenses
• Infected eye drops and lotions
• Infected instruments

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Conjunctivitis most common cause of Red Eye

• Types of conjunctivitis
• Bacterial
• Viral
• Allergic
• Secondary
• Chronic

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Bacterial Conjunctivitis

• Acute onset
• Bilateral
• Red, gritty, sore, puffy lids and purulent
  discharge
• Resolves within 5-10 days
• Rx G.Chlor or Fusidic acid

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Viral

• Acute onset
• Related to other URTI
• Likely to be Unilateral
• Red, gritty sore, Watery discharge
• Corneal staining with Fluorescien
• Diagnosis difficult in Primary Care therefore
  refer a unilateral red eye if no improvement
  within 48hrs of Rx
• Last for 3 -4 weeks

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Allergic

• Acute onset
• Bilateral
• Hx of exposure to allergens
• Hx Atopy or Fhx
• Sx very itchy,watery, chemosis (jelly like) of
  conj, puffy lids, follicles on Tarsal Plate
  (under eye lid)
• Responds to antihistamines, remove from cause
• Should respond immediately to Rx
• Prophylactic treatment recommended.

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Drugs for allergic conjunctivitis

• Topical antihistamine drops (H1 antagonists)
  antazoline, azelastine and levocabastine provide
  rapid relief and can be used for up to 4/52.
• If prolonged relief is required a mast cell
  stabiliser eg lodoxamide, nedocromil and sodium
  cromoglycate
• Start their use ideally 1/12 before allergy
  season
• Diclofenac is also licensed and steroids can be
  used only after examination on a slit lamp and
  seen by an ophthalmologist
• Eye sx alone are best treated topically, however
  if a pt has other sx oral antihistamines are
  recommended

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Secondary
Herpes Dendritic Ulcer
Corneal Abrasion
Corneal Ulcer, with pus in AC
Corneal Foreign Body
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Chlamydia

• Serotypes D-K are genital
• Serotypes A-C causes Trachoma worlds leading
  cause of blindness
• It attacks mucous membranes inhibits host cell
  protein synthesis
• Topical Rx tetracycline ointment QDS 6/52
• Systemic - Doxycycline, Tetracycline or
  Erythromycin

Under surface of eye lid (sub tarsal plate)
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Chloramphenicol

• Broad Spectrum Abx with least overall resistance
• It is a bacteriostatic and inhibits bacterial
  syntheses by reversibly binding to ribosome's
  which disrupts peptide bond formation and protein
  synthesis
• Acts on Gram ve and ve organisms
• MUST be stored in the fridge
• Bathe away discharge before use
• Regime 2 hourly in severe cases for 24 hours
  then QDS for 5 7 days.

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Side Effects/Cautions

• Stinging, local discomfort
• Greater chance of allergy than Fusidic acid
• Aplastic anaemia (bone marrow suppression) check
  FHx and GH
• Gray Baby syndrome
• Avoid in pregnancy, breast feeding and with
  caution in under ones
• Check bloods regularly if using long term
• Not sensitive to Pseudomonas

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Fusidic Acid

• Is a bacteriostatic and bactericidal agent with a
  steroid-like structure of no glucocorticoid
  activity.
• Inhibits bacterial protein synthesis and prevents
  elongation of the peptide chain.
• It is chemically unrelated to any other
  antibacterial in clinical use
• There is no cross-resistance nor cross
  sensitivity between Fusidic acid and other
  antibacterials
• It is microcrystalline giving it sustained
  release properties therefore concentration is
  maintained for 12 hours in lacrimal fluid and
  aqueous humour (BD dose regime)

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Side Effects/Cautions

• Stinging, local discomfort, burning redness and
  watering on initial instillation
• Allergic reactions are less than Chloramphenicol
• Not known to be harmful in pregnancy
• Is excreted in breast milk not known to be
  harmful weigh up risks/benefits.
• Can be local variations of resistance

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Antibiotic efficacy against common ocular
pathogens
Pathogen Known Activity Fusidic Acid Chloramphenicol
Staph Aureus
Staph epidermis
Strep pyogenes Sensitive
Strep pneumoniae Sensitive
Gonorrhoea
Escherichia coli Resistant
Haemophilus influenzae Sensitive
Pseudomonas Resistant Resistant
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OTC products for conjunctivitis

• Brolene and Golden Eye are antiseptic not
  antibiotic
• They are of little use
• They commonly cause an allergic reaction which
  compounds the patients symptoms
• They are used in acanthamoeba keratitis (organism
  grown on contact lenses)
• Chloramphenicol is now OTC

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Advice to patients

• Conjunctivitis is self limiting and will resolve
  without Rx in mild cases
• Clean eyes with cooled boiled water
• Avoid touching and rubbing eyes
• Wash hands after touching eyes
• Avoid sharing towels/face cloths
• Throw away make up that may be contaminated
• Contact Lenses SHOULD NOT be worn due episode and
  leave for 48hours after finishing Rx

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Contact Lenses

• Types include soft, hard (gas permeable)
  disposable and extended wear.
• Should not be worn during infections
• Strict hygiene, cleaning and maintenance should
  be encouraged at all times
• Soft CL are not compatible with drops that
  contain preservatives
• Soft CL absorb Fluorescein and permanently stain

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Instilling eye medication

• Drops contain preservatives to prevent
  micro-bacterial growth
• 1/12 shelf life-throw out after
• Clean discharge away first
• Wash hands
• Pull on lower eyelid to make a well drop
  solution or squeeze ointment into eye.
• Avoid touching the tip of the bottle with the eye

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Anti-virals

• Herpes Simplex and Zoster

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• Acyclovir (Zovirax) comes in tablet and oral form
  and used for both types of herpes. Ointment is
  used 5 x a day and compliance is essential to
  ensure disruption of the DNA synthesis.
• Pts should be monitored by an ophthalmologist as
  corneal scarring will occur
• Side effects from topical Rx include irritation,
  stinging, itching, inflammation, pain and
  photophobia

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Oral Topical Steroids

• Overdose or prolonged use can exaggerate some of
  the normal physiological actions of
  corticosteroids leading to mineralocorticoid and
  glucocorticoid side effects

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• Adrenal suppression amongst many things can cause
  Conjunctivitis.
• Suppression of infection - therefore masks sx and
  exacerbates infections e.g. bacterial, viral and
  fungal
• Causes next slide

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Cataract
Systemic steroids have a high risk (75) of
inducing a cataract
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Glaucoma
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Papilloedema
Sclera Thinning
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Amiodarone

• Used in Rx for arrhythmias
• Has a very long half life extending to several
  weeks.
• SEs can cause reversible corneal deposits
  (causes night glare), Optic neuritis causing
  blindness
• Treatment MUST be stopped and expert advice taken

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Amiodarone
Blurred Vision

• Optic Neuritis

Corneal Deposits
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Antimalarials

• Hydroxychloraquine and chloroquine are also used
  to treat Rheumatoid arthritis and SLE
• CAUSES
• Ocular Toxicity
• Retinal damage Keratopathy
• (Corneal Deposits)

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Royal College of Ophthalmologists

• Recommend regular ophthalmic examination
• Arrangement should be made locally between
  prescriber and ophthalmologist and agreed
  management plan for those on long term treatment
  of 5 yrs or more.
• Va - distance and near recorded before, during
  and after Rx
• Any visual impairment needs to be assessed and
  recorded before, during and after Rx
• Any deterioration in vision MUST be assessed by
  ophthalmologist
• Children receiving treatment for Juvenile
  Arthritis should be screened for Uveitis

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TB Drugs

• Ethambutol is included in a Rx regime when there
  is resistance to other TB drugs
• SEs Loss of VA
• Colour Blindness
• Reduction and restriction in Visual Field

The dark patches show loss of vision
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• Side effects are more common when given in
  excessive doses
• The drug should be stopped at the earliest
  presentation of ocular toxicity
• Always advise pts to stop Rx and seek medical
  and ophthalmic help
• Eye sight is nearly always restored if
  discontinuation of drug is early enough
• Pts who may not understand warnings about visual
  sx should be given an alternative TB drug if
  possible
• Children under 5 may not be able to report changes

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• Visual Acuity should be tested before starting
  treatment

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Other Systemic Drugs

• Tamoxifen oestrogen antagonist
• Causes visual disturbances including corneal
  changes, cataracts and Retinopathy
• Digoxin Toxicity causes visual disturbance
• MAOIs (monoamine oxidase inhibitors) causes
  blurred Va, Nystagmus and interacts with
  Sympathomimetics e.g. Phenylephrine (drug used to
  dilate pupil)

Retinopathy
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Diagnostic Drops

• Fluorescein Orange die
• Stains conjunctival and corneal epithelial damage
  e.g. corneal ulcers, erosions, and conjunctival
  or corneal abrasions

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• Assessment of dry eye
• Tonometry

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• Fluorescein is available as drops or as paper
  strips
• Fluorescein grows pseudomonas therefore is always
  used in single dose units

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• It is also used IV so photographs can be taken of
  retinal blood vessels, optic disc and macula

Blood vessels
Optic disc
Scar
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Rose Bengal

• Stains dead conjunctival and corneal epithelium
  in dry eye syndrome.
• It causes pain and stinging on instillation

Dead Corneal epithelium
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Dry Eyes
3 Layers of Tear Film
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Artificial Tears

• Are used for dry eyes and must be used as often
  as possible to keep the eyes feeling comfortable.
  
• Can be as often as every hour
• Once diagnosed drops will be necessary for life
• Dry, hot, windy conditions exacerbate sx also
  reading, using PC (Starring for long periods)

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Types

• Drops include Hypromellose, Tears Naturelle,
  Liquifilm
• Gel tears Viscotears bind with own natural
  tears and stay in eye for longer
• Ointments used at night, stay in eye for
  longer, can cause blurring of vision.

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List 3 things youve learnt

• 1
• 2
• 3
• Try and remember them!!!!

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Resources

• http//www.goodhope.org.uk/departments/eyedept/dro
  psfor.htm
• http//www.bnf.org
• Maclean H (2002) The Eye in Primary Care,
  Butterworth Heinmann.
• Galbraith et al (1999) Fundamentals of
  Pharmacology, Addison Wesley Longman Ltd
• Spalton et al (2006) Atlas of Clinical
  Ophthalmology 3rd Ed, Elsevier Mosby

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Any Questions