Cataract

Definition: Opacity of the lens that distorts the image projected on to the retina and which can progress to blindness.

Types of cataracts include: * * Senile * Congenital * Traumatic * Secondary

Anatomy and Physiology:

* Cornea - It is the outermost lens of the eye, controlling and focusing incoming light. It shields the rest of the eye from dust, germs and other harmful foreign matter. * Sclera - The visible white part of the eye.The sclera is a protective layer that maintains the global shape of the eye and offers resistance to internal and external forces. * Iris - The part of the eye which is colored. The iris is a diaphragm that regulates the expansion and contraction of the pupil to allow in the required amount of light. * Choroid – contains blood vessels and supplies nutrients to the retina. * Ciliary Body - Connects the choroids with the iris and secretes aqueous humor that helps the eye its shape. * Retina - The retina is the link between the brain and the light entering the eye. The retina is a complex structure able to convert the impacting light into nerve impulses that are then sent to the brain along the optic nerve. * Rods are photoreceptors responsible for peripheral vision and function at reduced levels of illumination. * Cones function at bright levels of illumination and are responsible for color vision and central vision. * Vitreous body – transmits light and gives shape to the posterior eye. * Vitreous (behind the lens) – gel-like substance that maintains the shape of the eye that provides additional support to the retina. * Optic disk – “blind spot”; it contains nerve fibers, lacks photoreceptor cells, and is insensitive to light. * Macula Lutea – it is where most acute vision occurs; concentration of photoreceptors. * Aqueous Humor – a fluid that fills the anterior and posterior chambers of the eye that is produced by the ciliary processes and drains into the Canal of Schlemm. * Canal of Schlemm – Permits the fluid to drain out of the eye into the systemic circulation so a constant intraocular pressure is maintained. * Lens – transparent structure behind the iris and in front of the vitreous body; refracts light. * Pupils – controls the amount of light that enters the eye and reaches the retina; dilates when dark and constricts when there’s light. * Conjunctiva – a thin transparent mucous membrane that protects the eye. * Lacrimal gland – responsible for tears * Eye Muscles – responsible for eye movement. 1) superior rectus, 2) inferior rectus, 3) lateral rectus, 4) medial rectus, 5) inferior oblique, 6) superior oblique * Nerves responsible for the sensory and muscle function of the eye: Oculomotor, Trochlear, Abducens, Optic (Sensory).

Etiology: Aging process, congenital (due to infection such as chickenpox, hepatitis, poliomyelitis, etc during the first trimester of pregnancy), Diabetes, Trauma/Injury

Symptomatology: * Clouded, blurred or dim vision * Increasing difficulty with vision at night * Sensitivity to light and glare * Seeing "halos" around lights * Frequent changes in eyeglass or contact lens prescription * Fading or yellowing of colors * Double vision in a single eye

Medical Management:

Diagnostic Tests: * Ultrasonography – calculates the length of the eye; determines the strength of intraocular lens after cataract extraction; it is used to determine gross outline changes in the eye and cloudy cornea. * Slit-Lamp Biomicroscopic Examination – allows examination of the anterior intraocular structures under microscopic magnification to visualize the narrow segment of the eye * Opthalmoscopy – views external and interior structures; examines the retina, optic disk, optic vessels, and macula; look for red reflex; absence of the red reflex may indicate opacity of the lens (cataract)
Medications:
* Mydriatics: Mydriatic eyedrops enlarge (dilate) the pupils of the eyes and may allow the person to see around a cataract. If a cataract is small, enlarging the pupil can allow the patient to see ‘around the cataract’ and perhaps avoid surgery. * Cycloplegics: used to paralyze ciliary muscles in order to determine the true refractive error of the lens.

Surgical Management:
Two surgical techniques are available: intracapsular cataract extraction (ICCE) and extracapsular cataract extraction (ECCE). * intracapsular cataract extraction (ICCE): incision is made in the cornea or the anterior sclera.
-entire capsule and lens are removed using the cryoprobe
-IOL is placed in the anterior chamber
-incision is then sutured close
-indication: subluxated cataractous lens * extracapsular cataract extraction (ECCE)- incision is made in the cornea or the anterior sclera (about 10 mm)
-the anterior capsule is opened
-nucleus expression
-aspiration of the lens cortex
-posterior chamber lens implanted into the capsular bag- using haptic lens

Nursing Diagnosis:

* Anxiety related to lack of knowledge.

1. Assess the degree and duration of visual impairment. Encourage conversation to find out the patient's concerns, feelings, and the level of understanding.
2. Orient the patient to the new environment.
3. Explain the perioperative routines.
4. Describes intervention much detail as possible.
5. Push to perform daily living habits when able.
6. Encourage participation of family or the people who matter in patient care.
7. Encourage participation in social activities and diversion whenever possible (visitors, radio, audio recording, TV, crafts, games).

* Risk for injury related to blurred vision

1. Help the patient when able to do until postoperative ambulation and achieve stable vision and adequate coping skills, using techniques of vision guidance.
2. Help the patient set the environment.
3. Orient the patient in the room.
4. Discuss the need for the use of metal shields or goggles when instructed
5. Do not put pressure on the affected eye trauma.
6. Use proper procedures when providing eye drugs.

* Acute pain related to trauma to the incision and increased IOP

1. Give medications to control pain and the IOP as prescribed.
2. Give cold compress on demand for blunt trauma.
3. Reduce the level of light
4. Encourage use of sunglasses in strong light.

* Risk for infection related to trauma to the incision
1. Maintain strict aseptic technique, do wash your hands frequently.
2. Supervise and report immediately any signs and symptoms of complications, such as: bleeding, increased IOP or infection.
3. Explain the recommended position.
4. Instruct the patient to know bed rest activity restrictions, with flexibility to the bathroom.
5. Describe the actions that should be avoided, as prescribed by coughing, sneezing, vomiting (ask for medication for it).
6. Give medications as prescribed, according to prescribed techniques.

* Impaired sensory perception

1. Determine visual acuity, note whether one or two eyes involved. 2. Orient clients to the environment 3. Observation signs of disorientation. 4. Approach from the side that was operated on, talk to touch. 5. Note about dim or blurred vision and eye irritation, which can occur when using eye drops. 6. Remind clients use of cataract glasses whose purpose enlarge approximately 25 percent, loss of peripheral vision and blind spotmay exist. 7. Put the items required / position call bell within reach.

* High risk of injury related to loss of vitreous, intraocular hemorrhage, increased IOP

1. Discuss what happens on the condition of post-surgery, pain, limitation of activity, performance, bandage the eye. 2. Give the patient the position back, head high, or tilted to the side that is not ill, according to patient preference. 3. Limit activities such as moving heads suddenly, scratched eyes, bent over. 4. Ambulation with assistance: give special bathroom when recovering from anesthesia. 5. Encourage deep breathing, coughing to maintain a healthy lung. 6. Encourage use stress management techniques. 7. Maintain eye protection as indicated. 8. Ask the client to distinguish between discomfort and a sudden sharp pain, Investigate anxiety, disorientation, impaired bandage. 9. Provide appropriate indication of antiemetic drugs, Asetolamid, analgesics.

Complications: * Vision Changes
The cataract will result in blurred vision that an eye doctor cannot fully correct with prescriptions eye glasses. Over time, reading, sewing and other close work will become difficult for a person with cataracts. If left alone, cataracts will gradually worsen, causing partial or complete blindness from the cloudiness of the lens. * Glare
A person with cataracts may likewise have difficulty with glare from normal room lighting and direct sunlight, says the National Eye Institute.

* Angle Closure Glaucoma
Drainage canals are located in front of the natural lens, helping to maintain a balanced pressure inside the eye. In cases of severe cataracts, the thick lens may push forward, causing a blockage of the drainage canal. When this occurs, the pressure inside the eye increases dramatically, causing severe pain, nausea and vomiting. Vision often decreases and the eye will likely appear red.

Prognosis:
Some cataracts stop progressing after a certain point. Cataracts are never reversible, however, even after eliminating factors (such as drugs or illnesses), which might have promoted their development. If extensive and progressive cataracts are left untreated they can cause blindness. In fact, cataracts are the leading cause of blindness among adults age 55 and older. Fortunately, cataracts nearly always can be successfully removed with surgery. However, surgery is unavailable in certain parts of the world, leaving millions at risk for vision loss. * Less light enters the retina * Vision Problems

* Signs and Symptoms: * Clouded, blurred or dim vision * Increasing difficulty with vision at night * Sensitivity to light and glare * Seeing "halos" around lights * Frequent changes in eyeglass or contact lens prescription * Fading or yellowing of colors * Double vision in a single eye * Less light enters the retina * Vision Problems

* Signs and Symptoms: * Clouded, blurred or dim vision * Increasing difficulty with vision at night * Sensitivity to light and glare * Seeing "halos" around lights * Frequent changes in eyeglass or contact lens prescription * Fading or yellowing of colors * Double vision in a single eye
CATARACT FORMATION
CATARACT FORMATION
Proteins in the lens clump together
Proteins in the lens clump together
Na, Ca
K, Ascorbic Acid, Proten Contents
Na, Ca
K, Ascorbic Acid, Proten Contents
Oxygen intake;
Initial in water content

Oxygen intake;
Initial in water content

Dehydration of the lens
Dehydration of the lens
Clouding of the Lens
Clouding of the Lens
Precipitating Factors: * Trauma/Injury * Alcohol
Precipitating Factors: * Trauma/Injury * Alcohol
Predisposing Factors: * Age * Congenital
Predisposing Factors: * Age * Congenital
Pathophysiology:

END.