Open-angle glaucoma: Difference between revisions

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== Open-angle Glaucoma ==
Open-angle glaucoma is an optic neuropathy characterized by an increase in intraocular pressure leading to damage to the optic nerve and irreversible vision loss. It most commonly presents with progressive peripheral vision loss, followed by central vision loss and is the second leading cause of irreversible blindness worldwide.


=== Pathophysiology ===
==Background==
Not entirely clear but may be related to an increased intraocular pressure that leads to compression of the optic nerve at the site where it exits the eye. This causes a progressive decrease in the number of retinal ganglion cells.
*Elevated intraocular pressure and resulting optic nerve damage manifested initially as visual field loss and ultimately irreversible blindness if left untreated
*Unclear pathogenesis, however thought to be related to two mechanisms:
**Increased aqueous production
**Decreased outflow


=== Risk Factors ===
==Clinical Features==
# Age. 4% prevalence in age >80
*Rarely experience symptoms, in contrast to [[acute angle closure glaucoma]]
# Race- 3x higher in African Americans
*Typical pattern characterized by progressive peripheral visual field loss followed by central field loss, usually but not always associated with elevated intraocular pressure
# Family History. 2-3 fold increase for individuals with affected sibling or parent
# Hypertension
# Diabetes
# Other: Myopia, pseudoexfoliation, low diastolic perfusion pressure, CV disease, Hypothyroidism


=== Clinical Presentation ===
==Differential Diagnosis==
* Painless
{{Acute vision loss noninflamed DDX}}
* Cupping of the optic disc
* Loss of peripheral visual field
* Preservation of central vision


=== Diagnosis with at least one of the following:===
==Evaluation==
* Evidence of optic nerve damage from structural abnormalities (thinning, cupping, notching of disc rim)
===Workup===
* Adult Onset
* Open, normal appearing anterior chamber angles
* Absence of known secondary causes of open-angle glaucoma


=== Diagnostic tests ===
===Diagnosis===
==== Fundus examination ====
*Characteristic nerve damage (eg, cupping) on fundus examination
* Cupping >50% of the vertical disc diameter
*Visual field abnormalities
* Thinning or notching of disc rim
*+/- elevated IOP
* Progressive change of size/shape of cup
==== Visual Field testing ====
==== Intraocular pressure ====
* Does not establish diagnosis of Open angle glaucoma. 1/2 of patients with OAG have normal intraocular pressure
* Normal Intraocular pressure ranges from 10 to 20 mmHg
* Pressure >21 mmhg considered ocular hypertension


=== Treatment and management ===
==Management==
* β-blockers: Timolol maleate 0.25%-0.5%, one drop BID
* α-adrenergic agonistBrimonidine 0.2% one drop BID
* Carbonic Anhydrase inhibitors: Dorzolamide 2% one drop BID
* Prostaglandins: Latanoprost 0.005% one drop qD
* Persistent elevated intraocular pressures: Acetazolamide 125-250mg PO bid-qid


=== Disposition ===
Indications for opthalmologic referral:
* IOP>40mmHg: emergency referral
* IOP 30-40 mmHg: referral within 24hr if no symptoms suggesting acute glaucoma
* IOP 25-29 mmHg: Evaluation within 1 week
* IOP 23-24 mmHg: repeat measurement and referral for comprehensive eye examination


=== References ===
==Disposition==
* Tsai LM, Pitha I, Kamenetzky SA. The Eye & Ocular Adnexa. In: Doherty GM. eds. CURRENT Diagnosis & Treatment: Surgery, 14e. New York, NY: McGraw-Hill; 2015.
 
* Weinreb RN, Khaw PT. Primary open-angle glaucoma. Lancet 2004; 363:1711
 
* UpToDate
==See Also==
* American Academy of Ophthalmology, Glaucoma Panel. Primary open-angle glaucoma. Preferred practice pattern. San Francisco: American Academy of Ophthalmology, 2000:1–36
*[[Acute angle-closure glaucoma]]
 
==External Links==
 
 
==References==
<references/>
 
[[Category:Ophthalmology]]

Latest revision as of 03:22, 7 December 2022

Background

  • Elevated intraocular pressure and resulting optic nerve damage manifested initially as visual field loss and ultimately irreversible blindness if left untreated
  • Unclear pathogenesis, however thought to be related to two mechanisms:
    • Increased aqueous production
    • Decreased outflow

Clinical Features

  • Rarely experience symptoms, in contrast to acute angle closure glaucoma
  • Typical pattern characterized by progressive peripheral visual field loss followed by central field loss, usually but not always associated with elevated intraocular pressure

Differential Diagnosis

Acute Vision Loss (Noninflamed)

Emergent Diagnosis

Evaluation

Workup

Diagnosis

  • Characteristic nerve damage (eg, cupping) on fundus examination
  • Visual field abnormalities
  • +/- elevated IOP

Management

Disposition

See Also

External Links

References