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Glaucoma with Ordinary Elevated Pressure: Recognizing Symptoms and Management Strategies

Glaucoma caused by typical pressure buildup: Recognizable signs and remedial measures

Glaucoma with Regular Pressure Levels: Recognizing Symptoms and Treatment Strategies
Glaucoma with Regular Pressure Levels: Recognizing Symptoms and Treatment Strategies

Glaucoma with Ordinary Elevated Pressure: Recognizing Symptoms and Management Strategies

Normal Tension Glaucoma (NTG), a type of glaucoma, is unique in that the pressure inside the eye falls within a typical range. Despite this, it can still lead to vision loss if left untreated.

What is Normal Tension Glaucoma?

NTG affects people without any initial symptoms, but when symptoms appear, they may include vision changes or loss, difficulty seeing in low-contrast situations, issues adjusting to bright or low light, glare from bright light, and changes in peripheral vision or visual field.

Risk Factors and Causes

Several factors may contribute to the development of NTG. These include age, ethnicity, family history, and conditions that affect blood vessels such as migraine, high blood pressure, low blood pressure at night, Raynaud's phenomenon, optic nerve hemorrhages, and other risk factors. Additionally, potential factors include vascular dysregulation, intracranial pressure, atypical functioning of the lamina cribrosa, neurodegenerative disorders, metabolic disorders, oxidative stress, and conditions that affect blood vessels.

Prevalence

NTG is more common in some populations than others. For instance, approximately 70% of people with primary open-angle glaucoma in Asia are diagnosed with NTG. In Africa, around 50% of people with primary open-angle glaucoma have NTG. Being female and older age may also increase the risk of developing NTG.

Associated Conditions

Certain conditions, such as obstructive sleep apnea and above-average intraocular pressure, can be signs of NTG. Additionally, having a history of migraine or optic disc hemorrhage can increase the risk of worsening vision problems in NTG. Thin central corneal thickness can also be a factor in the development of NTG.

Treatment

The primary goal of treating NTG is to lower intraocular pressure (IOP), even though the baseline IOP is within normal limits, as this is the only proven modifiable risk factor to slow progression and prevent vision loss.

Common treatment options include medications, such as topical eye drops like prostaglandin analogs, beta-blockers, or alpha agonists, which reduce fluid production or improve drainage to lower IOP. Laser therapy, such as Selective Laser Trabeculoplasty (SLT), improves aqueous outflow and can reduce IOP, though its effectiveness may vary.

If medications and laser therapy fail to control progression, surgical treatments like trabeculectomy or glaucoma drainage devices may be used. Trabeculectomy creates a new drainage channel to lower IOP and is currently the only treatment shown to provide sustained 24-hour IOP control.

Lifestyle modifications, such as dietary measures, avoiding excessive caffeine and salt, and general cardiovascular health support, can aid overall optic nerve health but cannot replace medical treatment.

Effectiveness

Lowering IOP by 20-30% from baseline in NTG patients has been shown to reduce the risk of disease progression and preserve vision. However, treatment is challenging due to low baseline IOP and nocturnal pressure peaks that are resistant to many medications. Trabeculectomy offers the most consistent 24-hour pressure control but carries higher risk and failure rates. Laser and medications are effective in many patients but sometimes insufficient alone to fully halt progression.

Regular monitoring with eye exams, visual field testing, and imaging is essential to detect progression early and adjust treatment promptly to prevent permanent vision loss. Untreated NTG usually leads to gradual optic nerve damage and vision impairment, so timely and sustained treatment aimed at lowering IOP remains the cornerstone of management.

  • Normal Tension Glaucoma (NTG) can be associated with neurological disorders and metabolic disorders, as well as conditions that affect blood vessels, such as migraine and high blood pressure.
  • People with NTG may also have an increased risk of vision loss if they have a history of optic disc hemorrhage, above-average intraocular pressure, or thin central corneal thickness.
  • When it comes to managing NTG, science and medical-conditions play a crucial role, as the primary goal is to lower intraocular pressure to prevent vision loss. This can be achieved through various treatments, including medications, laser therapy, and surgical procedures like trabeculectomy.

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