Glaucoma is a group of eye diseases which result in damage to the optic nerve and vision loss. A major risk factor is increased pressure in the eye. The disorders can be roughly divided into two main categories: "open-angle" and "closed-angle" (or "angle closure") glaucoma. Open-angle chronic glaucoma is painless, tends to develop slowly over time and often has no symptoms until the disease has progressed significantly. Closed angle glaucoma is usually chronic and asymptomatic but can present all of a sudden as well. This involves sudden eye pain, blurred vision, mid-dilated pupil, redness, nausea and vomiting, resulting from a sudden spike in intraocular pressure from iridotrabecular contact. Glaucoma can permanently damage vision in the affected eye, first by decreasing peripheral vision (reducing the visual field), and then potentially leading to blindness if left untreated.

The nerve damage involves loss of retinal ganglion cells in a characteristic pattern. Raised intraocular pressure (above 21 mmHg or 2.8 kPa) is the most important and only modifiable risk factor for glaucoma.

If the condition is detected early enough, it is possible to arrest the development or slow the progression with medical and surgical means. Open angle chronic glaucoma is treated with either glaucoma medication to lower the pressure, or with various pressure-reducing glaucoma surgeries. Treatment of closed angle glaucoma involves medication to bring the intraocular pressure down and laser surgery to the iris to open the drainage angle and hence reduce the eye pressure.

Glaucoma has been called the "silent thief of sight" because the loss of vision often occurs gradually over a long period, and symptoms only occur when the disease is quite advanced. Worldwide, glaucoma is the second-leading cause of blindness after cataracts.

Treatment and Medication

• Prostaglandin analogs, such as latanoprost, bimatoprost and travoprost, increase uveoscleral outflow of aqueous humor. Bimatoprost also increases trabecular outflow.
• Topical beta-adrenergic receptor antagonists, such as timolol, levobunolol, and betaxolol, decrease aqueous humor production by the epithelium of the ciliary body.
• Alpha2-adrenergic agonists, such as brimonidine and apraclonidine, work by a dual mechanism, decreasing aqueous humor production and increasing uveoscleral outflow.
• Less-selective alpha agonists, such as epinephrine, decrease aqueous humor production through vasoconstriction of ciliary body blood vessels, useful only in open-angle glaucoma. Epinephrine's mydriatic effect, however, renders it unsuitable for closed-angle glaucoma due to further narrowing of the uveoscleral outflow (i.e. further closure of trabecular meshwork, which is responsible for absorption of aqueous humor).
• Miotic agents (parasympathomimetics), such as pilocarpine, work by contraction of the ciliary muscle, opening the trabecular meshwork and allowing increased outflow of the aqueous humour. Echothiophate, an acetylcholinesterase inhibitor, is used in chronic glaucoma.
• Carbonic anhydrase inhibitors, such as dorzolamide, brinzolamide, and acetazolamide, lower secretion of aqueous humor by inhibiting carbonic anhydrase in the ciliary body.

Surgeries

• Laser surgery
• Trabeculectomy
• Glaucoma drainage implants
• Laser-assisted nonpenetrating deep sclerectomy

Prognosis

In open-angle glaucoma, the typical progression from normal vision to complete blindness takes about 25 years to 70 years without treatment, depending on the method of estimation used. The intraocular pressure can also have an effect, with higher pressures reducing the time until blindness.

Diabetic Retinopathy

Diabetic retinopathy, also known as diabetic eye disease, is when damage occurs to the retina due to diabetes. It can eventually lead to blindness.

It is an ocular manifestation of diabetes, a systemic disease, which affects up to 80 percent of all patients who have had diabetes for 20 years or more. Despite these intimidating statistics, research indicates that at least 90% of these new cases could be reduced if there were proper and vigilant treatment and monitoring of the eyes. The longer a person has diabetes, the higher his or her chances of developing diabetic retinopathy. Each year, diabetic retinopathy accounts for a sizeable percentage of all new cases of blindness. It is also the leading cause of blindness for people aged 20 to 64 years.

Diabetic retinopathy often has no early warning signs.

Various eye complications seen in a patient with Diabetic Retinopathy are Macular Oedema, Vitreous Haemorrhage, Cotton Wool Spots, Vascular fronds etc. Fluoresceinangiography can be done to see the back of the eye. Narrowing or blocked retinal blood vessels can be seen clearly and this is called retinal ischemia (lack of blood flow).

Optical Coherence Tomography can show the areas of retinal thickening (due to fluid accumulation) of macular edema.

Risk Factors: Uncontrolled Diabetes, Coexisting Hypertension, Pregnancy, certain chromosomal disorders.

Diagnosis: Fundus Examination, Fluorescein Angiography, Optical Coherence Tomography.

Treatment:

• Laser photocoagulation
• Modified Grid Laser photocoagulation
• Panretinal photocoagulation
• Intravitreal triamcinolone acetonide
• Intravitreal anti-VEGF drugs
• Intravitreal injectable Devices (OSURDEV)
• Vitrectomy

Advanced Diagnostic Eye Tests

Eye360 - Param Jyoti has advanced equipments for precise diagnosis of conditions such as Glaucoma, Age Related Macular Degeneration, Diabetic Retinopathy, etc.

Optical Coherence Tomography (OCT)

Optical coherence tomography is a non-invasive imaging test that uses light waves to take cross-section pictures of your retina, the light-sensitive tissue lining the back of the eye.

With OCT, each of the retina's distinctive layers can be seen, allowing your ophthalmologist to map and measure their thickness. These measurements help with diagnosis and provide treatment guidance for glaucoma and retinal diseases, such as age-related macular degeneration and diabetic eye disease.

Fundus Fluorescein Angiography (FFA)

Fundus Fluorescein Angiography is a medical procedure in which a fluorescent dye is injected into the bloodstream. The dye highlights the blood vessels in the back of the eye so they can be photographed.

Your doctor may require a Fundus Fluorescein Angiography to determine if the blood vessels at the back of your eye are getting adequate blood flow. It is also used to diagnose eye disorders, such as macular degeneration or diabetic retinopathy.

Visual Field Testing

Visual field tests are used to detect blind spots (scotomas), which could be a sign of eye diseases. The size and shape of a scotoma offer important clues about the presence and severity of diseases of the eye, optic nerve and visual structures in the brain. Many eye and brain disorders can cause peripheral vision loss and other visual field abnormalities.

For example, optic nerve damage caused by glaucoma creates a very specific visual field defect. Other eye problems associated with blind spots and other visual field defects include optic nerve damage (optic neuropathy) from disease or damage to the light-sensitive inner lining of the eye (retina).