What Is Glaucoma? Symptoms and Treatment

Ocular hypertension, medically referred to as glaucoma, is a chronic disease that damages the optic nerve as a result of increased intraocular pressure. It may progress without symptoms in its early stages and can cause permanent vision loss if left untreated.

Risk factors for glaucoma include advanced age, family history, high intraocular pressure, and systemic diseases. In individuals who do not undergo regular eye examinations, the disease may be diagnosed late and is usually advanced by the time visual field loss is noticed.

Diagnosis involves measuring intraocular pressure, evaluating the optic nerve, and performing visual field tests. Early diagnosis is the most important step in stopping the progression of the disease. People in risk groups should undergo regular examinations.

Eye drops, laser procedures, and surgical interventions may be used in treatment. The aim is to control intraocular pressure and protect the optic nerve. Regular follow-up and adherence to treatment play a critical role in managing the disease.

Ocular hypertension, also known as glaucoma, is an eye disease that damages the optic nerve and usually progresses silently. It develops as a result of increased intraocular pressure and may lead to permanent vision loss if left untreated. It may not cause symptoms initially. In advanced stages, it manifests as peripheral vision loss. Regular eye examinations are important for early diagnosis. Eye drops, laser treatment, or surgical procedures may be used.

Ocular hypertension, also known as elevated intraocular pressure, or IOP, is the most important risk factor for glaucoma and may result from many different causes. The main cause is an imbalance between the production and drainage of the fluid in the eye known as aqueous humor. The eye continuously produces this fluid and drains it through pathways such as the canal of Schlemm. Blockages or anatomical abnormalities affecting this process may cause IOP to increase.

Open-Angle Glaucoma:

• In open-angle glaucoma, one of the most common types of glaucoma, the drainage angle remains open, but extracellular material accumulation and structural changes in the trabecular meshwork prevent the fluid from draining adequately. This condition usually develops slowly and chronically.

Angle-Closure Glaucoma:

• In angle-closure glaucoma, the iris moves forward and narrows or completely blocks the drainage angle. This may cause a sudden and severe increase in IOP and requires emergency intervention.

Genetic Factors:

• Genetic predisposition plays an important role in the development of glaucoma. Mutations in genes such as MYOC, which encodes myocilin, and CYP1B1 are particularly associated with primary open-angle glaucoma and congenital glaucoma. These mutations may disrupt the structural integrity of eye tissues and prevent fluid drainage.

Secondary Causes:

• Certain conditions may increase intraocular pressure:
• Eye Trauma: Injuries may cause blockages in the trabecular meshwork.
• Inflammation: Inflammatory conditions such as uveitis disrupt drainage.
• Medications: Long-term corticosteroid use may increase IOP.
• Lens Problems: Lens-related conditions such as cataracts may obstruct drainage.

Vascular Factors:

• Circulatory disorders, particularly inadequate blood flow to the optic nerve head, may increase the risk of glaucoma even when IOP levels are normal. Conditions such as systemic hypotension and atherosclerosis contribute to this type of damage.
• Damage caused by elevated intraocular pressure can be prevented with early diagnosis and appropriate treatment.

Glaucoma is one of the leading causes of irreversible blindness worldwide, and its prevalence varies depending on factors such as age, sex, geography, and ethnicity. According to 2019 data, 7.47 million people worldwide were affected by glaucoma. Although this figure represents a 92.53% increase since 1990, the decline in the age-standardized prevalence rate reflects advances in detecting and treating the disease.

The prevalence of glaucoma increases significantly with age. Individuals aged 40 and over are at higher risk. Among individuals aged 70 and over, the glaucoma rate reaches 112.9 per 100,000, demonstrating the vulnerability of this age group. Glaucoma prevalence is slightly higher among men than women, but the difference is minimal. However, women are at greater risk of certain types, such as angle-closure glaucoma, or ACG.

The geographical distribution of glaucoma varies considerably. Asia accounts for nearly half of all glaucoma cases worldwide, and a large proportion of these cases are identified as ACG. Primary open-angle glaucoma, or POAG, is more common among people of African descent. For example, African Americans have a sixfold higher risk of glaucoma than White Americans. This demonstrates the effects of genetic and environmental factors on glaucoma.

Rates of vision loss caused by glaucoma are higher in regions with low socioeconomic status. Considering the aging population and increasing demographic changes, the global prevalence of glaucoma is expected to reach 111.8 million people by 2040. Early diagnosis and treatment strategies are therefore vital for reducing the global burden of glaucoma.

Ocular hypertension develops as a result of an abnormal increase in intraocular pressure, or IOP. This condition results from an imbalance between the production and drainage of aqueous humor, the fluid within the eye. The main processes affecting intraocular pressure are the production, circulation, and outflow pathways of aqueous humor.

• Aqueous Humor Production and Circulation:

Aqueous humor is produced in the ciliary body, and three main mechanisms are involved in this production process: diffusion, ultrafiltration, and active secretion. Active secretion is an energy-dependent process and primarily occurs through the transport of ions and water from the ciliary epithelium into the posterior chamber. This fluid flows from the posterior chamber through the pupil into the anterior chamber, where it nourishes avascular structures such as the lens and cornea. It also contributes to maintaining intraocular pressure.

• Aqueous Humor Outflow Pathways:

Maintaining normal intraocular pressure depends on the balance between the production and drainage of aqueous humor. There are two main outflow pathways:

Trabecular, or Conventional, Outflow Pathway: Aqueous humor drains from the anterior chamber through the trabecular meshwork and canal of Schlemm into the episcleral veins. This pathway plays a fundamental role in regulating intraocular pressure.

Uveoscleral, or Unconventional, Outflow Pathway: Some of the aqueous humor passes through the ciliary muscles and other anterior segment structures into the supraciliary and suprachoroidal spaces, where it is absorbed into the systemic circulation.

• Pathophysiological Changes:

Ocular hypertension is generally associated with increased resistance in the drainage pathways rather than excessive aqueous humor production. Dysfunction of the trabecular meshwork, extracellular matrix accumulation, cellular loss, and cytoskeletal changes may make drainage more difficult. In angle-closure glaucoma, the iris tissue may also physically obstruct the trabecular meshwork and stop drainage.

Glaucoma is an eye disease that generally progresses silently and does not cause noticeable symptoms in its early stages. It is therefore described as the "silent thief of sight." In open-angle glaucoma, its most common form, symptoms are generally noticed as the disease progresses. Peripheral, or side, vision loss may occur initially, but patients usually do not notice this loss. When the disease reaches more advanced stages, individuals may experience tunnel vision. In this situation, central vision remains clear while peripheral vision is significantly reduced.

Angle-closure glaucoma presents with more acute and sudden symptoms. Patients may experience severe eye pain, headache, nausea, vomiting, blurred vision, and halos around lights. Angle-closure glaucoma requires emergency medical intervention because it can rapidly cause optic nerve damage and permanent vision loss.

In the less common normal-tension glaucoma, optic nerve damage and vision loss may occur even though intraocular pressure remains within normal ranges. This form can be diagnosed through detailed eye examinations.

Regular eye examinations are critically important for the early detection and effective treatment of glaucoma. Individuals with a family history of glaucoma, people over the age of 40, and those with risk factors such as diabetes should not neglect regular examinations. Early diagnosis is the most effective step in preventing vision loss.

Diagnosing ocular hypertension, or glaucoma, requires a comprehensive eye examination to protect eye health and enable early intervention. This process includes evaluating several factors, including intraocular pressure, or IOP, the condition of the optic nerve, and the visual field.

• Tonometry: This test measures the pressure inside the eye and is a fundamental method for diagnosing glaucoma. Goldmann applanation tonometry, the most commonly used method, provides precise and reliable results. Other methods, including non-contact air-puff tonometry and electronic indentation tonometry, may also be used.
• Ophthalmoscopy: This method is used to examine the structure of the optic nerve and is important for detecting glaucoma-related damage. During an examination performed with pupil-dilating drops, the shape and color of the optic nerve are evaluated in detail. Stereoscopic biomicroscopy provides three-dimensional imaging and allows for a more detailed examination.
• Perimetry: A visual field test is used to identify vision loss specific to glaucoma. The patient's responses to various light stimuli are used to determine losses within the visual field. Repeating this test regularly is important for monitoring the progression of the disease.
• Gonioscopy: This test examines the angle between the iris and cornea and is critical for determining the type of glaucoma. The procedure evaluates the eye's drainage system and helps guide the treatment plan.
• Optical Coherence Tomography, or OCT: This technique provides detailed images of the retina and optic nerve and detects changes in the nerve fiber layer at an early stage.
• Fundus Photography and Ultrasound Biomicroscopy: These methods support the diagnostic process by imaging the internal structures of the eye and helping to plan surgical interventions.

The aim of glaucoma treatment is to reduce intraocular pressure, or IOP, prevent optic nerve damage, and avoid vision loss. Treatment options include medications, laser treatments, and surgical interventions. Treatment is personalized according to the patient's type of glaucoma, IOP level, and rate of disease progression.

• Medical Treatment:

Medications generally constitute the first stage of treatment. Eye drops or oral medications control IOP by either reducing aqueous humor production or increasing drainage. Prostaglandin analogs, such as latanoprost, provide effective results when applied once at night. Beta-blockers, such as timolol, reduce aqueous humor production, while alpha-2 agonists, such as brimonidine, and carbonic anhydrase inhibitors, such as dorzolamide, are beneficial through their dual mechanisms. Regular use and monitoring for side effects are critical during medical treatment.

• Laser Treatments:

Laser treatments may be used when medications are insufficient or patient adherence is low. Argon Laser Trabeculoplasty, or ALT, and Selective Laser Trabeculoplasty, or SLT, aim to increase drainage through the trabecular meshwork. For patients with angle-closure glaucoma, Laser Peripheral Iridotomy, or LPI, is an effective option for regulating aqueous humor flow. Laser treatments offer rapid recovery times and are minimally invasive.

• Surgical Interventions:

Surgical methods are preferred in advanced cases of glaucoma when medication and laser treatments are insufficient. Trabeculectomy is the gold standard in glaucoma treatment and effectively lowers IOP by creating a new drainage pathway. Glaucoma drainage devices, or GDDs, and Minimally Invasive Glaucoma Surgery, or MIGS, are among the options for complex cases. Careful postoperative follow-up is vital for preventing infection and scar formation.

Ocular hypertension can cause serious and irreversible complications, particularly when left untreated. The most common and significant complication of glaucoma is progressive vision loss. This develops as a result of optic nerve damage and usually affects peripheral vision first. Patients often do not notice a problem at this stage because vision loss begins in the peripheral areas rather than the center. If left untreated, however, this loss may result in tunnel vision and eventually lead to complete blindness. Even in developed countries, glaucoma is one of the leading causes of irreversible blindness.

Vision loss caused by untreated glaucoma seriously affects not only patients' quality of life but also their independence and ability to perform daily activities. Basic activities such as driving, reading, or continuing occupational activities may become difficult or impossible. Patients may experience psychological consequences such as depression, anxiety, and social isolation.

Complications of ocular hypertension may also have negative effects on an individual's social and economic well-being. Loss of workforce participation, treatment costs, and the need for care resulting from blindness may place a significant burden on families and healthcare systems.

Early diagnosis is critical for preventing the progression of glaucoma and minimizing complications. Regular eye examinations are particularly important for risk groups, including older adults, individuals with a family history of glaucoma, and people with diabetes. When ocular hypertension is diagnosed, a treatment plan appropriate to the course of the disease should be developed. Reducing intraocular pressure through medications, laser interventions, or surgical methods can reduce pressure on the optic nerve and slow vision loss.

The timing of glaucoma treatment varies depending on the course of the disease, the level of intraocular pressure, and the severity of optic nerve damage. The main aim of treatment is to lower intraocular pressure to a safe level and stop or slow optic nerve damage. The patient's lifestyle, other health problems, and ability to adhere to treatment should also be considered when making treatment decisions.

Treatment usually begins with medication. Topical medications such as prostaglandin analogs, which lower intraocular pressure, are preferred as the first-line treatment. These medications generally provide ease of daily use while producing effective results. However, laser treatments or surgical options may be considered when medical treatment is insufficient or cannot be tolerated because of side effects.

Laser treatments are an effective option, particularly for patients who cannot adhere to medication use or do not benefit from medical treatment. Selective Laser Trabeculoplasty, or SLT, is frequently preferred for open-angle glaucoma. Its low-risk profile and repeatability provide advantages.

Surgical interventions are preferred in advanced cases of glaucoma or when other treatment methods are insufficient. Intraocular drainage devices can effectively control intraocular pressure. Early intervention plays a critical role in preventing vision loss. Regular eye examinations should therefore not be neglected.

Contraindications for Laser Treatments:

• Laser treatments reduce IOP by improving the function of the trabecular meshwork. However, they are not appropriate in certain situations:
• Angle-Closure Glaucoma: Laser treatment is ineffective when the drainage angle is closed, and other methods are required.
• Inflammatory or Neovascular Glaucoma: Active inflammation or abnormal blood vessel growth may cause complications after laser treatment.
• Advanced Glaucoma: Laser treatment may present more risk than benefit in patients with significant optic nerve damage.
• Corneal Edema and Cataracts: These conditions may prevent the laser beam from reaching the target tissue and reduce the effectiveness of treatment.

Contraindications for Intraocular Drainage Devices:

• Devices such as shunts or valves increase fluid outflow but cannot be used under certain conditions:
• Active Ocular Infections: Placing a device during an infection may worsen the condition.
• Severe Ocular Surface Diseases: Dry eye or conjunctival scarring may make healing more difficult.
• Implant Allergy: Sensitivity to the materials used in the device may cause serious reactions.
• Uncontrolled Systemic Diseases: Conditions such as diabetes or hypertension may increase surgical risks.

Contraindications for Medical Treatments:

• Each type of eye drop and oral medication should not be used under certain conditions:
• Beta-Blockers: They may cause bronchospasm or cardiac problems in people with respiratory or heart diseases.
• Alpha-2 Agonists: They are contraindicated in infants and young children because of the risk of apnea.
• Prostaglandin Analogs: They should be used cautiously in patients with active inflammation or a history of herpes.
• Carbonic Anhydrase Inhibitors: They are contraindicated in patients with a sulfonamide allergy or severe kidney or liver failure.

Recovery after treatments used for ocular hypertension may vary depending on the type of treatment and the individual's health condition. However, all treatment approaches share the goal of controlling intraocular pressure and preventing vision loss. Certain important points should be considered to optimize recovery and minimize the risk of complications.

• Recovery After Laser Treatments:

Argon Laser Trabeculoplasty, or ALT, and Selective Laser Trabeculoplasty, or SLT, generally have a rapid recovery period. Patients can return to their daily activities within a few days after treatment. Temporary side effects may occur during this period, including mild discomfort, light sensitivity, and blurred vision. These effects are usually short-lived and resolve spontaneously. Regular use of anti-inflammatory eye drops and attendance at follow-up appointments are very important for the success of treatment.

• Recovery After Surgical Interventions:

Recovery may take longer after surgical treatments such as the implantation of tube shunts or Minimally Invasive Glaucoma Surgery, or MIGS, devices. During this period, patients are advised to avoid heavy lifting, rubbing their eyes, and positions in which the head is lowered. Symptoms such as redness, swelling, and watering may occur after surgery, but they are generally temporary. Antibiotic and anti-inflammatory drops are prescribed to reduce the risk of infection. Using a protective eye shield is particularly helpful for preventing eye injuries at night.

• Medical Treatment:

Although medical treatment does not require surgical intervention, regular use of eye drops is critical for treatment effectiveness. Medications keep intraocular pressure at the target level and slow the progression of glaucoma. Regular medical checkups are used to assess treatment adherence and side effects.

Elevated intraocular pressure, or IOP, and the resulting glaucoma may be prevented or their progression may be slowed through early diagnosis and appropriate lifestyle changes. The first step is to closely monitor IOP through regular eye examinations. These examinations are particularly vital for people over the age of 40 and those with a family history of glaucoma. Routine screenings detect early changes in the optic nerve, increase the possibility of treatment, and prevent permanent vision loss.

Lifestyle changes are also an important part of preventive strategies. Regular physical activity may naturally reduce IOP and increase blood flow to the optic nerve. However, exercises that may cause intense pressure, such as weightlifting, should be avoided. Dietary changes also support eye health. Consuming vegetables and fruits rich in antioxidants is particularly important. Avoiding excessive caffeine consumption prevents temporary increases that may negatively affect IOP. Quitting smoking also helps reduce oxidative stress and vascular dysfunction in eye tissues.

Finally, prescribed treatments should be followed and regular checkups should not be missed. Medications that reduce intraocular pressure and other treatments can only be effective when used regularly and monitored. Patients should work closely with their ophthalmologists to keep intraocular pressure under control and monitor the progression of the disease. Eye health can be protected through regular care and informed choices.

Yes, sleeping position can affect intraocular pressure. Keeping the head flat in a horizontal position may increase intraocular pressure. It is therefore recommended to elevate the head by approximately 20 degrees while sleeping, which can be achieved by using several pillows. This position may help lower intraocular pressure and play a supportive role in glaucoma management.

Is There a Relationship Between Ocular Hypertension, or Glaucoma, and Nutrition?

Yes, a healthy diet plays an important role in controlling intraocular pressure. Foods rich in antioxidants support eye health and may reduce intraocular pressure. Consuming foods such as green leafy vegetables, carrots, broccoli, citrus fruits, fish, walnuts, and almonds is particularly recommended. Drinking enough water also helps keep intraocular pressure under control.

What Is the Relationship Between Ocular Hypertension, or Glaucoma, and Exercise?

Regular exercise has positive effects on general health and may also help reduce the risk of ocular hypertension, or glaucoma. Aerobic exercise in particular may reduce intraocular pressure and lower the risk of developing glaucoma. Activities such as walking, running, cycling, and swimming may help lower pressure by improving the drainage of intraocular fluid. However, exercises involving heavy lifting or inverted positions may increase intraocular pressure, so patients with glaucoma are advised to avoid such activities.