Jane Goodwin BSc, MSc Nurse Practitioner

1. Jane Goodwin BSc, MScNurse Practitioner Drugs and the Eye

2. A&P

3. A & P

4. 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.

6. 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

7. 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.

8. 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.

9. Administration • Locally – direct into lower eye lid.

10. Subconjunctival injection – space between conj and sclera

11. Retrobulbar Injection - into muscle cone behind the eye

12. Peripubulbar – into space around the eye • Intraocular – into the eye eg Anterior Chamber Intraocular Lens

13. Contact lens – impregnated and placed on cornea Edge of lens

14. Absorption • Drugs applied topically enter the eye through the cornea • There are 5 layers to the Cornea Descemet’s Membrane Internal Layer Endothelium

15. 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

16. Other factors affecting absorption • Drops can be lost from the eye before they cross the cornea. Occlude Inner Canthus

17. 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

18. 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

19. 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

20. 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 MAOI’s (monoamine oxidase inhibitors) – risk of hypertensive crisis

21. 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)

22. 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.

23. Normal Flow Acute blockage

24. 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 IOP’s. • Avoid in conditions where a miosed pupil would be undesirable ie Iritis and Uvietis

25. 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.

26. Circulation of Aqueous = problem with aqueous drainage

27. 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

28. 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)

29. 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).

30. Alpha 2 Agonists • Is used as add on therapy when beta blockers are not enough to reduce IOP or when B’blockers 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)

31. Prostaglandin Analogues • Work by increasing uveoscleral outflow • Uses – open angle glaucoma and *ocular hypertension • Ocular SE – browncolour 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.

32. 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 pt’s with hypertension and heart disease.

33. Tunnel Vision

34. Coffee Time !

35. 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

36. Conjunctivitis – most common cause of Red Eye Types of conjunctivitis • Bacterial • Viral • Allergic • Secondary • Chronic

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

38. 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

39. 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.

40. 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

41. Secondary Herpes – Dendritic Ulcer Corneal Abrasion Corneal Ulcer, with pus in AC Corneal Foreign Body

42. 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)

43. 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.

44. 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

45. 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)

46. 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

47. Antibiotic efficacy against common ocular pathogens

48. 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

49. 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

50. 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