Class 8 (2/25/21) - Ocular disorders

Question 1

Lens

Answer 1

Located behind iris

Question 2

Retina

Answer 2

Inside eye ball

Question 3

Optic nerve

Answer 3

Second nerve, sensory nerve, carries visual messages from retina to brain

Question 4

Macula

Answer 4

Central part of retina, provides detailed vision

Question 5

______ are the number one leading cause of blindness in the world.

Answer 5

Cataracts

Question 6

Cataract

Answer 6

Abnormalities of lens clarity

Question 7

Senile cataract

Answer 7

Age related cataract

Question 8

Risk factors for cataract?

Answer 8

• Exposure to UV light (higher in sunny climates)

- Remember that UV light is a risk factor for skin cancer also

Question 9

Cataract symptoms:

Answer 9

• Painless, progressive loss of vision
• Patients may first notice image blur as the lens loses its ability to resolve separate and distinct objects
• Glare from bright lights at night or even during the day – (result of light rays being scattered by the opacities)
• Over time, lens opacities progress and interfere with vision.
• Reading becomes difficult, even with glasses

Question 10

What is second sight?

Answer 10

• When lens opacities first develop, visual acuity is relatively unaffected, but the refractive index and thus the refractive power of the lens increases (i.e., the lens shifts toward myopia).
• Thus, in a person aged 60 to 70, early lens changes may induce myopia and allow the person to read again without glasses

Question 11

Eye examination in cataract?

Answer 11

• Lens opacities can be seen easily by observing the red reflex of the retina with an ophthalmoscope
• A lens opacity appears as a black area

Question 12

Cataract treatment:

Answer 12

• cataract extractions

- removal of the native lens and placement w/ an intraocular lens (i.e. a plastic prosthetic lens)

Question 13

Cataract surgery:

Answer 13

an elective surgery which means potential benefits should clearly outweigh the possible complications and discomfort

Question 14

Is cataract surgery considered successful?

Answer 14

• Yes, cataract surgery is one of the most successful surgical procedures; about95% of patients have excellent vision after the surgery.
• Most patients have little pain after surgery; pain can be controlled with acetaminophen (Tylenol)

Question 15

Glaucoma

Answer 15

Disorders characterized by increased intraocular pressure that can lead to irreversible damage to the optic nerve and impaired vision

Question 16

Can glaucoma cause blindness?

Answer 16

Yes, Glaucoma accounts for about 10% of all cases of blindness in the USA

Question 17

Increased intraocular pressure occurs because of

Answer 17

either increased production or impaired outflow of aqueous fluid
=» impaired outflow is more common

Question 18

How many types of glaucoma?

Answer 18

• Angle closure glaucoma (narrow angle glaucoma): 10% of glaucoma cases in the USA, but it is the only type that can be cured.
• Open-angle glaucoma: more common in US, it can’t be cured

Question 19

Angle closure glaucoma

Answer 19

=acute glaucoma, narrow angle glaucoma
- The fluid is still being produced by the ciliary body, but it can’t be drained due to closed angle (the angle between iris and cornea)

Question 20

Angle closure glaucoma symptoms

Answer 20

There is a rapid rise in intraocular pressure, with redness and pain in or around the eye, severe headache, nausea, vomiting, and blurred vision
- During an acute glaucoma attack, the eye is tender and feels firmer than the other eye.

Question 21

The anterior chamber of the eye is bounded anteriorly by the ____ and posteriorly by the ___ and ____

Answer 21

Cornea, iris & lens

Question 22

The anterior chamber becomes shallower with age because …

Answer 22

the lens continues to thicken throughout life, moving the iris forward

Question 23

_____ persons tend to have smaller eyes and thus may be predisposed to angle closure glaucoma in later life

Answer 23

Farsighted

Question 24

gonioscope is for?

Answer 24

examination of the angle structures

Question 25

angle-closure glaucoma must be referred? Why?

Answer 25

Yes, it is an emergency requiring immediate referral to an ophthalmologist. Within 48 to 72 hours, depending on the pressure elevation, vision may be irreversibly damaged.

Question 26

When an ophthalmologist is unavailable, what’s the next step?

Answer 26

• local instillation of one drop of 2% pilocarpine every 5 minutes four to six times along with IV administration of acetazolamide 5 to 10 mg/kg

=» just know pilocarpine (drop), acetazolamide (injection)

Question 27

What’s the mechanism of pilocarpine?

Answer 27

It facilitates the rate that aqueous humor leaves the eye to decrease intraocular pressure

Question 28

What’s the mechanism of acetazolamide?

Answer 28

reduces the amount of fluid produced in the eye and this helps reduce the high-pressure present inglaucoma

Question 29

What’s the only cure of angle-closure glaucoma?

Answer 29

surgical intervention (laser iridotomy)

Question 30

Open-Angle Glaucoma?

Answer 30

Glaucoma associated with an anatomically open anterior chamber angleabout 80% of glaucoma in the USA (just know it is more common compared to closed-angle)

Question 31

Which types of glaucoma is more dangerous?

Answer 31

Open angle, because this type of glaucoma is asymptomatic until very late

Question 32

What are symptoms of Open-Angle Glaucoma?

Answer 32

It causes a gradual loss of visual fields over years and affects both eyes simultaneously. loss of peripheral vision develops insidiously and is usually unnoticed by patients until advanced.
There is generally no pain

Question 33

If the angle is open in Open-Angle Glaucoma, what’s the problem

Answer 33

There is a resistance to outflow

Question 34

If the angle is open in open-angle glaucoma, how it can be detected?

Answer 34

• Routine intraocular pressure monitoring and ophthalmoscopy examination of the optic nerve may detect open-angle glaucoma in the absence of symptoms.
• optic atrophy (manifest as cupping)

Question 35

Open-angle glaucoma vs ocular hypertension

Answer 35

• When the pressure is > 21 mm Hg but the patient has no visual field defect, the diagnosis is ocular hypertension.
• In open-angle glaucoma, the ocular pressure is high, the visual field has decreased also

Question 36

Tx of open-angle glaucoma?

Answer 36

• Although open-angle glaucoma cannot be cured, it can usually be controlled with topical and systemic therapy. - Whether or not the patient has symptoms, drugs are needed to reduce intraocular pressure to prevent irreversible optic nerve damage and thus the loss of peripheral visual fields.

Medications:

• Prostaglandin analogues: first line for tx of open-angle glaucoma, it increases aqueous outflow
• Beta Blockers

Question 37

Can Diabetic retinopathy cause blindness?

Answer 37

Yes, it is the third leading cause of blindness in US

Question 38

Macular edema (Pooling of fluid in the macula) is a hallmark of …

Answer 38

diabetic retinopathy

Question 39

Can retinal detachment happen in diabetic retinopathy?

Answer 39

Yes

Question 40

Symptoms of diabetic retinopathy?

Answer 40

Symptoms may be subtle (e.g., early visual loss from macular edema, a shower of spots, clouded vision)

Question 41

Diabetic patients should have ___ eye examination

Answer 41

annual

Question 42

Tx of diabetic retinopathy?

Answer 42

Laser therapy

Question 43

What is Macular degeneration?

Answer 43

• The macula is the area of the retina responsible for detailed, fine central vision.
• Macular degeneration refers to a series of pathologic changes in the macula accompanied by decreased visual acuity.

Question 44

Signs and symptoms of Macular degeneration?

Answer 44

• Patients may notice distortion of central vision with objects appearing larger or smaller or straight lines appearing distorted, bent, or without a central segment. - If central vision is distorted in only one eye, the patient is unlikely to notice any change in vision. However, if the patient views a grid of fine lines with each eye alternately, distortion can be quickly detected.

Question 45

Patients considered at high risk for age-related maculopathy are given …

Answer 45

a grid to view daily. So, the macular degeneration can be diagnosed soon

Question 46

Treatment of macular degeneration?

Answer 46

• Laser treatment can be beneficial in some cases
• Patients who have decreased central visual acuity cannot read or drive a car, but can continue to perform many daily activities