Disorders of the eye

Cataract

Definition

occurs when an opaque or cloudy area develops in the normally clear lens (responsible for the focusing mechanism) of the eye

Symptoms

Blurry or cloudy vision that cannot be corrected with glasses or contact lenses

Increasing difficulty with vision at night

Need for brighter mild when analyzing and enticing in different activities

Glare

Presence of haloes round light sources

Fading of colours, every now and then with a yellowish tint

Double vision in one eye

Pathophysiology

in age-related cataract, the pathogenesis of cataract development is multifactorial and includes the foDrug or chemical toxicity. Toxic cataracts result from drug or chemical toxicity with prednisone, ergot alkaloids, dinitrophenol, naphthalene, phenothiazines, or pilocarpine, or from extended exposure to ultraviolet rays
Clinical Manifestationsllowing factors: Compaction and stiffening of the central lens material (nuclear sclerosis) as new layers of cortical (outer lens) fibers continue to proliferate over time.

Causes

Degenerative changes. Senile cataracts develop in elderly patients, probably because of the degenerative changes in the chemical state of lens proteins.

Nursing interventions

Recent medication intake. It is a common practice to withhold any anticoagulant therapy to reduce the risk of retrobulbar hemorrhage.

Genetic defects. Congenital cataracts occur in neonates s genetic defects or as a sequela of maternal infections during the first trimester

Foreign body injury. Traumatic cataracts occur after a foreign body injures the lens with sufficient force to allow aqueous or vitreous humor to enter the lens capsule and also dislocate the lens.

Secondary effects. Complicated cataracts occur as secondary effects in patients with uveitis, glaucoma, or retinitis pigmentosa, or in the course of a systemic disease, such as diabetes, hypoparathyroidism, or atopic dermatitis.

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Visual acuity test results. Test results from Snellen’s and other visual acuity tests are assessed.

Providing preoperative care. Use of anticoagulants is withheld to reduce the risk of retrobulbar hemorrhage.

Instill eyedrops as prescribed

Glaucoma

condition of increased pressure within the eyeball, causing gradual loss of sight.

Pathophysiology

The main problem or pathology in glaucoma is caused by raised intraocular pressure. It is this raised pressure that compresses and damages the optic nerve. Once the optic nerve is damaged, it fails to carry visual information to the brain and this results in loss of vision.

Causes

high or elevated blood pressure

Symptoms

Severe are pain

Nausea

Vomiting

Redness in the eye

Sudden vision disturbance

Seeing coloured rings around lights

Sudden blurred vision

poor or reduced blood flow to your optic nerve

Dilating eye drops

medications, such as corticosteroids

Nursing interventions

Demonstrate administration of eye drops (counting drops, adhering to the schedule, not missing doses

Assist with administration of medications as indicated:

Provide sedation, analgesics as necessary.

preventing further visual deterioration

promote adaptation to changes in reduced visual acuity, prevent complications and injury.


Amblyopia

Definition

Decreased eyesight due to abnormal visual development.

Pathophysiology

Amblyopia is a cortical developmental disorder, secondary to abnormal visual inputs to each eye occurring early in life (during the cortical plasticity stage) where in dissimilar action potentials (in amplitude or time, or both) generated in the retina reach the cortex.

Causes

Muscle imbalance (strabismus amblyopia).

Difference in sharpness of vision between the eyes (refractive amblyopia).

Deprivation. A problem with one eye — such as a cloudy area in the lens (cataract) — can prohibit clear vision in that eye.

Symptoms

An eye that wanders inward or outward

Eyes that appear to not work together

Poor depth perception

Abnormal results of vision screening tests

Head tilting

Squinting or shutting an eye

Nursing interventions

Corrective eyewear. Glasses or contact lenses can correct problems such as nearsightedness, farsightedness or astigmatism that result in lazy eye.

Eye patches. To stimulate the weaker eye, your child wears an eye patch over the eye with better vision for two to six or more hours a day. In rare cases, wearing an eye patch too long can cause amblyopia to develop in the patched eye. However it's usually reversible.

Bangerter filter. This special filter is placed on the eyeglass lens of the stronger eye. The filter blurs the stronger eye and, like an eye patch, works to stimulate the weaker eye.

Eyedrops. An eyedrop of a medication called atropine (Isopto Atropine) can temporarily blur vision in the stronger eye. Usually prescribed for use on weekends or daily, use of the drops encourages your child to use the weaker eye, and offers an alternative to a patch. Side effects include sensitivity to light and eye irritation.

References