6.1.8 Flashcards
What is glaucoma?
A condition that affects your eyes, causing damage to the optic nerve due to high pressure inside the eye or normal pressure.
Glaucoma often leads to vision loss, particularly in peripheral vision, and typically shows no symptoms until significant damage has occurred.
What are the primary risk factors for glaucoma?
- Age
- Family History
- Elevated Intraocular Pressure (IOP)
- Ethnicity
- Other Eye Conditions
- Medications
- Other Systemic Conditions
These factors significantly increase the risk of developing glaucoma.
How does age affect the risk of glaucoma?
The risk increases with age, especially after 40, peaking at 70-80 years for open-angle glaucoma (OAG).
Incidence increases rapidly after age 60.
What is the significance of family history in glaucoma risk?
A strong family history, especially in first-degree relatives, significantly increases the risk of developing glaucoma.
Genetic predisposition is documented in both primary open-angle glaucoma (POAG) and angle-closure glaucoma (ACG).
What is ocular hypertension (OHT)?
An elevated intraocular pressure (greater than 21 mmHg) that is a major risk factor for glaucoma, though not all with OHT will develop glaucoma.
An IOP consistently above the normal range can damage the optic nerve over time.
Which ethnicities are associated with a higher risk of glaucoma?
- African-Caribbean and African descent
- Asian populations (higher risk of angle-closure glaucoma)
- Latino populations (higher risk for glaucoma, especially angle-closure types)
Ethnicity plays a significant role in glaucoma risk.
What ocular conditions increase the risk of developing glaucoma?
- Myopia
- Diabetes
- Previous eye injury
- High refractive errors
- Cataracts
- Optic nerve abnormalities
These conditions indicate higher vulnerability to glaucoma.
What medications are known to increase the risk of glaucoma?
Chronic use of corticosteroids, which can raise IOP and lead to secondary glaucoma, commonly referred to as steroid-induced glaucoma.
This includes topical, systemic, or inhaled corticosteroids.
What systemic conditions may increase glaucoma risk?
- High blood pressure
- Diabetes
- Vascular issues
- Sleep apnea
These conditions can affect ocular perfusion and increase the risk of glaucoma.
What are the key clinical examination findings for open-angle glaucoma?
- Optic nerve head changes (cupping, pallor, notching)
- Visual field defects (peripheral loss)
- Elevated IOP
- Wide-open anterior chamber angle (gonioscopy)
These findings help diagnose open-angle glaucoma.
What are the symptoms of closed-angle glaucoma?
- Painful red eye
- Halos around lights
- Nausea/vomiting
- Corneal edema
- Mid-dilated pupil that is non-reactive to light
Closed-angle glaucoma is a medical emergency requiring immediate attention.
When should a patient be referred for glaucoma?
- Elevated IOP (above 21 mmHg) with risk factors
- Suspicious optic nerve changes
- Visual field defects suggestive of glaucoma
- Clinical presentation of angle-closure glaucoma
- Normal-tension glaucoma with optic nerve damage risk
Referral is crucial for timely management.
What steps are crucial in managing suspected glaucoma?
- Monitor IOP regularly
- Optic nerve head imaging
- Visual field testing
- Referral for comprehensive glaucoma assessment
- Management of diagnosed conditions
These steps help in early detection and management.
What is optic disc cupping?
An increase in the depth or size of the central depression (the cup) in the optic disc, often seen in glaucoma.
A normal cup-to-disc ratio is typically 0.3 or lower; in glaucoma, this ratio increases, often reaching values of 0.6 or higher.
What does optic disc pallor indicate in glaucoma?
A pale appearance of the optic disc due to loss of nerve fibers and diminished blood flow to the optic nerve.
This is usually a sign of chronic damage in glaucoma.
What is notching of the optic disc?
Localized loss of optic nerve tissue at the rim of the optic disc, particularly at the edges of the cup.
This occurs due to asymmetric nerve fiber loss affecting specific areas of the optic nerve head.
What are the treatment options for glaucoma?
- Eye drops to lower eye pressure
- Laser treatment to improve fluid drainage
- Surgery (trabeculectomy, tube shunt) if necessary
Treatment depends on the severity and type of glaucoma.
What is trabeculectomy?
A surgery performed when eye pressure is too high despite medication or laser treatment, creating a new drainage hole in the eye.
It is effective in reducing eye pressure and requires regular follow-ups.
What is tube shunt surgery?
A procedure involving placement of a small tube in the eye to help fluid drain properly, used in more complicated cases.
It may require post-operative eye drops for healing.
What is laser peripheral iridotomy?
A laser treatment for angle-closure glaucoma that creates a hole in the iris to allow fluid to drain properly.
This quick procedure prevents serious increases in eye pressure.
What is laser trabeculoplasty?
A laser procedure for open-angle glaucoma that helps the drainage system function better to lower eye pressure.
It is a quick procedure, often done in an office setting.
What symptoms indicate the urgency of treatment for angle-closure glaucoma?
- Intense eye pain
- Nausea
- Blurry vision
Immediate treatment is crucial to prevent permanent vision loss.
What is the optic cup?
The optic cup is a central depression in the optic disc.
How does the optic cup change in glaucoma?
In glaucoma, the loss of nerve fibers leads to the characteristic appearance of a notch in the optic disc rim.
In which areas of the optic disc does notching typically occur in glaucoma?
Notching typically occurs in the inferior or superior regions of the disc.
What is the neuroretinal rim?
The neuroretinal rim is the tissue around the optic disc that contains the nerve fibers of the optic nerve.
How does the neuroretinal rim change in glaucoma?
In glaucoma, the neuroretinal rim becomes thinner, particularly in the inferior and superior portions.
What can happen to the neuroretinal rim in some cases of glaucoma?
The rim can become wider or thicker in areas where nerve fibers are preserved or where there is compensatory hypertrophy.
Why does the neuroretinal rim thin in glaucoma?
The thinning occurs as nerve fibers are lost and the tissue shrinks.
What is enlargement of the optic cup?
Enlargement of the optic cup refers to an increase in the size of the central cup area in relation to the optic disc.
How does the optic cup size change in glaucoma?
As glaucoma progresses, damage to nerve fibers results in an expansion of the optic cup and a larger cup-to-disc ratio.
Why does the optic cup size increase in glaucoma?
The increase in cup size occurs due to the loss of nerve fibers and subsequent atrophy of optic nerve tissue.
What is the retinal nerve fiber layer (RNFL)?
The RNFL consists of the nerve fibers that come from the retina and travel toward the optic nerve.
How does the RNFL change in glaucoma?
The RNFL begins to thin, which can be seen using imaging techniques like optical coherence tomography (OCT).
What may be visible during a fundus examination in advanced glaucoma?
Areas of localized nerve fiber loss may be visible around the optic disc.
Why does the RNFL thin in glaucoma?
Glaucoma causes the death of retinal ganglion cells and the atrophy of their axons, leading to thinning of the RNFL.
What is parapapillary atrophy (PPA)?
Parapapillary atrophy refers to changes in the area around the optic disc, appearing as a pale, irregular area or loss of pigment.
How does PPA change in glaucoma?
PPA is often seen in advanced stages of glaucoma associated with thinning or loss of retinal nerve fibers.
Why does PPA occur in glaucoma?
PPA occurs due to degenerative changes around the optic nerve from damage and atrophy of nerve fibers.
What signs necessitate an urgent referral to hospital eye services for glaucoma?
Optic disc signs consistent with glaucoma, reproducible visual field defects, risk of angle closure
Signs include optic disc cupping, pallor, or notching indicative of glaucomatous damage, and detection of visual field loss patterns consistent with glaucoma.
What are optic disc signs consistent with glaucoma?
Optic disc cupping, pallor, notching
These signs indicate glaucomatous damage.
What constitutes reproducible visual field defects in glaucoma?
Detection of visual field loss patterns consistent with glaucoma
This is critical for diagnosis and monitoring of glaucoma.
What does the Van Herick technique assess in relation to glaucoma?
Peripheral anterior chamber width
A width of ¼ or less of the corneal thickness indicates a risk for angle-closure glaucoma.
What criteria must patients meet for optometrist-led glaucoma care?
Stable glaucoma, regular monitoring, no recent hospital attendance
Stable glaucoma refers to well-controlled intraocular pressure (IOP) and no progression of optic nerve damage.
What defines ‘stable glaucoma’ in the context of optometrist-led care?
Well-controlled intraocular pressure (IOP) and no progression of optic nerve damage
This is essential for ensuring patient safety and effective management.
What does ‘regular monitoring’ entail for patients in optometrist-led glaucoma care?
Routine assessments of IOP, optic disc appearance, visual fields
Monitoring should be without evidence of disease progression.
Why is it important for patients to have no recent hospital attendance for optometrist-led glaucoma care?
To ensure continuity of care within the community setting
This helps maintain effective management without overlapping treatments.
What is Retinal Nerve Fiber Layer (RNFL) thinning?
A reduction in the thickness of the RNFL, indicating loss of retinal ganglion cell axons in glaucoma.
RNFL thinning is often first observed in the inferior and superior quadrants.
How does OCT detect RNFL thinning?
OCT measures the thickness of the RNFL around the optic disc.
It is useful for diagnosing pre-perimetric glaucoma.
What does RNFL thinning signify in glaucoma?
It is a critical early sign of glaucoma, preceding detectable optic disc cupping.
What is optic disc cupping?
An increase in the size and depth of the optic cup relative to the optic disc, indicative of glaucoma.
Thinning of the neuroretinal rim can also be detected.
How does OCT detect optic disc cupping?
OCT provides a detailed 3D topographic map of the optic nerve head.
This helps visualize the size of the optic cup and thickness of the neuroretinal rim.
What is the clinical significance of optic disc cupping?
An increased cup-to-disc ratio and thinning of the neuroretinal rim suggest glaucomatous optic neuropathy.
What does Macular Ganglion Cell Complex (GCC) thinning indicate?
Damage to ganglion cells in the macular region due to glaucoma.
GCC consists of the retinal ganglion cell layer, inner plexiform layer, and nerve fiber layer.
How does OCT measure GCC thinning?
OCT specifically measures the thickness of the GCC in the macula.
GCC thinning can indicate early central vision involvement in glaucoma.
What is the significance of GCC thinning in glaucoma?
It is a sensitive indicator of glaucomatous damage and can signal central vision involvement before optic disc changes are visible.
What are localized RNFL defects around the optic nerve head?
Thinning or defects in the RNFL indicating glaucoma.
These defects correspond to areas of the retina where ganglion cells are dying.
How does OCT detect localized RNFL defects?
OCT creates a detailed map of RNFL thickness around the optic nerve head.
What is the clinical significance of localized RNFL defects?
They are strong indicators of glaucomatous optic neuropathy and can assist in diagnosing pre-perimetric glaucoma.
What does decreased cup-to-disc ratio indicate?
An enlargement of the optic cup and thinning of the neuroretinal rim in glaucoma.
This leads to an increased cup-to-disc ratio.
How does OCT measure the cup-to-disc ratio?
OCT provides quantitative measurements to track changes over time.
What is the clinical importance of an increasing cup-to-disc ratio?
It signifies progressive glaucomatous damage and helps assess disease severity.
What structural changes in retinal layers can OCT reveal?
Early changes due to glaucomatous damage before they become clinically apparent.
This includes subtle changes in the inner retinal layers.
How does OCT detect structural changes in the retinal layers?
By scanning the retina to capture detailed cross-sectional images.
Why are changes in retinal layers clinically significant?
They can provide early evidence of glaucomatous damage before significant visual field loss occurs.
What is the primary role of gonioscopy in glaucoma?
To examine the anterior chamber angle for aqueous humor drainage
This drainage system regulates intraocular pressure (IOP), which is crucial in glaucoma management.
What characterizes Open-Angle Glaucoma?
The anterior chamber angle remains open, but the trabecular meshwork does not function properly
Gonioscopy may show a wide open angle with signs of trabecular meshwork dysfunction.
Define Closed-Angle Glaucoma.
The anterior chamber angle becomes narrow or closed, preventing proper drainage of aqueous humor
This condition can cause a rapid increase in IOP.
What does gonioscopy reveal in Closed-Angle Glaucoma?
A narrow or occluded angle, often with iris bulging or pupillary block
This finding is critical for diagnosing angle-closure glaucoma.
How does gonioscopy assess the risk of angle-closure glaucoma?
It identifies narrow angles that could predispose patients to angle-closure glaucoma
Early detection allows for intervention to prevent acute angle-closure attacks.
What types of glaucoma can gonioscopy help classify?
- Primary open-angle glaucoma
- Secondary angle-closure glaucoma
- Neovascular glaucoma
Classification determines the appropriate treatment approach.
What is Shaffer’s grading system used for?
To assess the degree of openness of the anterior chamber angle during gonioscopy
The grading ranges from 0 (closed) to 4 (wide open).
What does Grade 4 indicate in Shaffer’s grading system?
The angle is wide open and unobstructed
This is the best possible grade for angle openness.
What does Grade 0 indicate in Shaffer’s grading system?
The angle is closed, and no structures are visible
This suggests severe blockage in the drainage pathway.
What is the gold standard for detecting angle-closure glaucoma?
Gonioscopy
It identifies the anterior chamber angle’s openness, crucial for risk assessment.
Why is monitoring angle changes important in gonioscopy?
To allow for early intervention to prevent IOP elevation or optic nerve damage
This is particularly important for patients with narrow angles.
What treatments may be guided by gonioscopy findings?
- Laser iridotomy
- Laser iridoplasty
- Surgical intervention
These treatments aim to improve aqueous humor drainage.
What is the purpose of laser iridotomy?
To create a small hole in the peripheral iris to improve aqueous humor drainage
This is used when gonioscopy reveals a closed or narrow angle.
What conditions can gonioscopy help diagnose that lead to elevated IOP?
- Neovascular glaucoma
- Traumatic glaucoma
- Pseudoexfoliation syndrome
These conditions can affect the angle due to various factors.
What is the Radial Disc Scan?
This scan focuses on the optic disc, the area where the optic nerve enters the eye.
It helps assess the cup-to-disc ratio and nerve fiber layer thickness.
What does the Radial Disc Scan show?
It provides a detailed view of the optic nerve head and helps assess the cup-to-disc ratio and nerve fiber layer thickness.
Changes in the optic nerve head can indicate early signs of nerve damage due to glaucoma.
What is the clinical use of the Radial Disc Scan?
It’s mainly used for glaucoma management.
Changes in the optic nerve head are critical indicators in glaucoma.
What is the Macula Map Scan?
This scan creates a detailed map of the macula, the central part of the retina responsible for sharp central vision.
It helps monitor the health of the central retina.
What does the Macula Map Scan show?
It provides information about the thickness of the macula and can identify areas of swelling, fluid, or cyst formation.
It detects early signs of conditions like macular degeneration, diabetic retinopathy, or macular edema.
What is the clinical use of the Macula Map Scan?
It’s used to monitor conditions that affect the central retina.
It provides insights into how well the macula is functioning.
What is the Macula Radial Scan?
This scan uses multiple lines radiating out from the fovea in a radial pattern, focusing on the macula.
It is similar to the Radial Disc Scan but concentrates on the macula.
What does the Macula Radial Scan show?
It gives a detailed view of the macula’s structure, identifying changes in the retinal layers such as thickening, swelling, or fluid.
It helps detect conditions like macular edema or diabetic retinopathy.
What is the clinical use of the Macula Radial Scan?
This scan is used for monitoring macular health, particularly in conditions affecting central vision.
It provides insights into swelling or changes in the macula across different angles.
