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Drusen: build up of material between Bruch's and the RPE.

Exudates: Vascular leakages. More superficial than drusen and more clearly defined.

Laser treatment:

Fresh: pale lesions with poorly defined margins.

Overtime they become larger in size.

Stargardt's macular dystrophy

Routine referral.

Inherited/1st/2nd decade with VI.

Initially non-specific mottling at the fovea.

Star shape.

Tamoxifen

Anti-oestrogen drug for breast cancer.

Bilateral, yellow, star shape.

Management for a patient with symptoms and distortion - urgent referral.

Exudates - refer as it could be life threatening --> within 1DD of fovea - urgent referral.

Secondary glaucomas.

PDS.

Young men, myopes.

Iris bows and pigment is shed into the anterior chamber.

As the process continues, you can see trans-illumination in the iris area.

Pigment cells on the corneal endothelium - Krukenberg's spindles.

It can lead onto PDG, if the trabecular meshwork becomes blocked.

Pseudoexfoliation.

Old women, hyperopes.

White dandruff material accumulates on the anterior lens surface/pupil margin/angle.

IOP increases due to increased resistance to outflow.

Dilated fundus check to see the anterior lens.

LA prevent and generate nerve impulses.

Potential side effects:

Reduced blink reflex.

Repeat instillations lead to desquamation of the corneal epithelium.

Allergic response/ester link compounds.

Rose Bengal 1% stains dead corneal and conjunctival epithelial cells.

Inducing CAG.

Rise of 2mmHg: nothing.

Rise of 4mmHg: retain patient and recheck every 30 minutes until the pressure falls.

Rise of 9mmHg: Very worrying. Phone casualty and inform them of the situation with a view to urgently refer and inform the GP.

Signs and symptoms:

Sudden onset of violent eye/head pain and nausea.

Pupil is mid-dilated and fixed.

Hazy cornea due to oedema.

Send/take to Casualty.

Peripheral iridotomy:

Aqueous flow from the anterior chamber to the posterior chamber.

Recurrent closures can cause iris synechiae.

III: SR. MR. IR. IO.

IV: SO.

VI: LR.

Muscle sequelae:

Primary u/a

Contralateral synergist o/a

Ipsilateral antagonist o/a

Secondary u/a of the contralateral antagonist.

Binocularly balancing.

Finding the maximum plus to balance the spherical element of the refractive error, whilst maintaining best acuities.

Hypertension

High blood pressure can lead to a stroke, amaurosis fugax or dry eyes.

Drugs for control: Beta blockers, diuretics, ACE inhibitors, CCB.

HT is a risk factor for CRVO.

A stroke is an interruption of blood flow; where the vessels supplying the brain get blocked/damaged. Thus the brain doesn't receive oxygen and the area dies.

Diabetes.

This condition becomes most damaging to the eyes, when the blood vessels within the eye begin to leak.

If your diabetes isn't under control, this could cause fluctuations in your vision.

Cataracts also progress more quickly.

Background retinopathy: exudates, microaneuryms, dot and flame haemorhhages.

Pre-proliferative retinopathy: all the above, CWS.

Proliferative retinopathy: neovascularisation at the disc and elsewhere.

Maculopathy can also be a cause of sight loss.

It is treated with focal or diffuse laser photocoagulation. It can cause a slight reduction in the peripheral vision.

#eye #eyes #diabetes #diabetic retinopathy #retina #retinopathy

Strabismus.

This is where the eyes don't work correctly together, they don't receive the same images and this prevents proper binocular vision, affecting depth perception.

Treatment:

Correct the refractive error.

Occlude the good eye, forcing the "bad" eye to work.

Eye drops work in the way that occlusion does, blurring the good eye, forcing the "bad" eye to work.

Surgery.

#eye #eyes #strabismus

Glaucoma.

Glaucoma is where the optic nerve becomes damaged leading to characteristic visual field defects. It can be associated with an increase in intraocular pressure.

An increase in the IOPs is due to an increased aqueous production or a resistance to aqueous outflow through the trabecular meshwork.

There are two theories as to the cause of the damage:

Mechanical theory. As the ganglion nerve fibres pass the laminar cribosa to form the optic nerve, they pass through large pores superiorly and inferiorly, smaller pores are temporal and nasally. The increase of IOP can cause compression and shearing through the pores, damaging and killing the nerve fibres, leading to a characteristic field defect.

Vascular theory. The increase in IOP causes death of the blood vessels surrounding the bundles of nerve fibres, leading to a characteristic field defect.

Risk factors: Age (40+), FH, race (Afro-Caribbean) and myopes.

Management would be via IOP lowering drops: Prostanglandin analogue drops would be first choice/Xalatan.

#eye #eyes #glaucoma #IOP #optic nerve

Cataract.

Clouding of the lens, which causes vision to become hazy. As the deposits/opacities increase, the vision becomes more affected as light cannot pass onto the back of the eye/retina.

It is a slow progressive condition, which once affecting your quality of life, can be removed.

You will be referred via your GP to an ophthalmologist who will undertake a pre-assessment, to check your vision and the state of the cataract. If deemed suitable for surgery, it will take place, normally 6 weeks from the date of referral.

The surgery takes 30-40 minutes by an ophthalmologist under local anesthetic.

You can leave the same day but you do have to take two types of drops: antibiotic drops to prevent infection and steroid drops to prevent inflammation.

At the end of it, your vision will be better for distance but since the lens has been replaced by an artificial lens, which cannot change focus, glasses will be necessary and you will be told to return to an optometrists for a check up.

The procedure is very safe, with a 97% success rate but as with all procedures, there is a slight risk of complications.

#cataract #cataracts #crystalline lens #eye

AMD

The macular, which is the area responsible for central vision degenerates.

Dry AMD is more common and develops gradually over time.

Wet AMD causes a greater risk of losing sight.

No treatment for Dry AMD but there are several treatments for Wet AMD, the primary one being anti-VEGF intravitreal injections, every 4 weeks, until the fluid subsides, potentially for life.

Laser photocoagulation burns the new vessels, preventing their growth and the VEGF production.

Photodynamic therapy where a Verteporfin dye is inserted and once through the new blood vessels, is sealed with a cold laser.

Risk factors are: FH, age, race (White Caucasians), UV exposure and smoking

Improve diet by eating fresh fruits and dark leafy vegetables.

Vitamin C,E and beta carotenes (non-smokers)

Lutein, Xeazanthin

Presbyopia.

Normal age related changes in the lens cause it to become less flexible and you can't focus at near as easily as before.

#presbyopia

The optic nerve sheaths are an extension of dura around the brain. It is in direct communication with the CSF flowing around the brain.

When there is high pressure of the CSF, the pressure extends around the optic nerve, causing an obstruction of the axoplasmic flow in the ON axons.

A build up of blocked axoplasm in the ONH becomes visible as swelling, causing the appearance of bilateral papilloedema.

E.g. brain tumour, stoke, trauma

Tropicamide inhibits the parasympathetic nervous system, also reducing tear secretion and causing cycloplegia. There is no light reflex.

Phenylephrine stimulates the sympathetic nervous system, acting on the peripheral blood vessels and Muller's muscle. The sphincter muscle still works. There is a light reflex.

If they can fuse the images with Bagolini lenses, they have HARC or suppression.

Fixation disparity is the area around Panum's area where BSV is maintained.

Under stress, FD can break down into a decompensated heterophoria.

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