P15

What are the two segments of the eye?

Anterior, posterior

Describe dry eye?

Not enough tears produced

Treatment for dry eyes?

Lubricant to induced pulsed light therapy

Describe Blepharitis?

Inflamed eye lids

Treatment for Blepharitis?

Eyelid cleansing treatments

Describe conjunctivitis?

Pink eye, inflamed conjunctiva, allergic, bacterial, viral

Describe Uveitis?

Inflamed uvea tract

Treatment for Uveitis?

Steroid treatment or surgery

Describe keratoconus?

Gradual thinning of cornea, forms a cone shape

Treatment for keratoconus?

Contact lenses, corneal cross linking, keratoplasty

Define cataract?

Portion of lens hardens and becomes cloudy, crystals form and harden

Symptoms of cataracts?

Can be annoying to painful, range of blurred vison, sensitivity to glare

Causes of cataracts?

Age, eye injury, previous surgery, certain medications

Treatment of cataracts?

Replacement of lens with a plastic lens

Define Age-related macular degeneration (AMD)?

Degeneration of central part of retina causing loss of focus, irreversible

Treatment of AMD?

No cure but can manage symptoms, reducing abnormal blood vessel growth

Define Central Serous Retinopathy?

Disorder of the outer blood retinal barrier, fluid build up under retina, causing delamination

Treatment of CSR?

Laser based therapies

Define Glaucoma?

Fluid build up leading to change in intraocular pressure, causing irreversible optical nerve damage

Symptoms of Glaucoma?

Headaches, nausea, haloes around light, asymptomatic till later stages

Causes of glaucoma?

Age, ethnicity, genetic profile, other underlying diseases

Types of glaucoma?

Primary open angle, acute angle closure, secondary glaucoma

Treatment of glaucoma?

Depending severity, eye drops, laser, surgery

What barrier are there in the eye?

Conjunctiva, cornea, lacrimal fluid, difficult to deliver small volumes via eye drops

Define conjunctiva?

Thin transparent epithelial layer coving the inside of the eyelids and part of the eye ball, help produce and maintain tear film

Define cornea?

Clear surface above iris and pupil, allowing light to enter the eye

Describe the epithelium layer of cornea?

Lipid rich next to conjunctiva, 1 week turnover for cells

Describe the stroma layer of cornea?

Thickest layer composed of collagen matrix and keratinocytes, collagen fibril bundle spacing contributes to cornea being clear

Describe the endothelium layer of cornea?

single cell layer lipid rich to maintain hydration

How does the cornea affect drug characteristics?

Lipid rich so drugs need to have lipophilic properties, avascular, negatively charge

Describe the purpose of lacrimal fluid?

Distribute nutrients across the eye, maintain hydration and remove debris

What is composition of the lacrimal fluid?

Water, lipids, lysozyme, lipocalin, glucose and sodium, it is isotonic with blood

What is the pH of the lacrimal fluid?

7\.4 good buffering properties which could affect drug formulations

How are topical optical formulations made sterile?

Clean conditions followed by autoclaving /filtering or fully aseptic from start

How are topical optical formulations kept chemically stable?

Preservatives as most eye drops multi dose

Why does the pH of topical optical formulations need to be considered?

Due to the buffering potential of the lacrimal fluid

Why is viscosity important for topical optical formulations?

Formulation needs to be filtered, sterilised and compatible with other excipients

Why is salt match important for topical optical formulations?

Solubility, high concentrations can cause irritation

Why is comfort important for topical optical formulations?

Can affect tear production and clearance, adherance

What is particle size for topical optical formulations?

Under 10 microns

Why do topical optical formulations need to be amphipathic?

The cornea’s lipid aqueous lipid structure

Describe the characteristics of optical ointments?

Semi solid and solid hydrocarbons melting point of ocular room temp 34C

Describe the advantages of optical ointments?

Help sustain drug release, improves bioavailability, increases retention time

Describe the disadvantages of optical ointments?

Viscosity, greasiness, blurred vision, prolonged exposure can lead to irritation, systemic complications with chronic administration

Define Periocular delivery?

Around the eye ball, transscleral pathway less invasive, some times there is a drainage issue

Define Intravitreal delivery?

Into the vitreous, distribution not uniform, particle size, MW, chemistry matters

What is iluvien?

Implant for Chronic Diabetic Macular Oedema, sits in vitreous fluid, reduce VEGF

What is advantages of nanocarrier in optical drug delivery?

Decrease irritation, improve dispersion, improve tissue compatibility

How could contacts be used for optical drug delivery?

Impregnating contacts, improving resistance time, drug loading issues

How could micro needles be used for optical drug delivery?

Minimally invasive to intravitreal, penetrates only 100s of microns into sclera