How Do Macular Degeneration Agents Work?

Macular degeneration agents are medications that slow down macular degeneration by preventing the growth of abnormal new blood vessels (neovascularization) in the retina. Each type of macular degeneration agent works uniquely to stop neovascularization.

Retina is the innermost layer of light sensitive tissue on the inside of the eyeball, which enables vision by sending signals through the optic nerve to the brain. Macula is the central part of the retina, which has a high concentration of photoreceptor cells and is responsible for central and color vision and fine details of images.

Age-related macular degeneration (AMD) occurs in people above 50 years of age and if untreated, can cause loss of central vision, although peripheral vision is unaffected. AMD is of two types:

• Dry AMD: Dry AMD is the more common type, accounting for over 85% of the cases. In dry AMD, small white or yellow deposits known as drusen form on the macula which gets thinner. Progression of dry AMD is slow, but currently, there is no treatment for dry AMD.
• Wet AMD: Although less common, wet AMD is more serious and progresses faster. Wet AMD is caused by abnormal neovascularization in the retina, which can leak blood or fluids into the retina, leading to scarring and degeneration of the macula. Wet AMD is treated with macular degeneration agents.

Most macular degeneration agents work by inhibiting the activity of a protein known as vascular endothelial growth factor (VEGF) that stimulates new blood vessel growth. Anti-VEGF macular degeneration agents are fragments of protein molecules that bind to VEGF and block their activity.

One of the macular degeneration agents is a photosensitizing drug that is used along with a laser beam to destroy neovascular growth.

The anti-VEGF macular degeneration agents are all solutions administered as intravitreous injections. Vitreous is the clear gel-like substance that fills the eyeball space between the lens and the retina. The photosensitizing agent used in laser treatment of the macula is intravenously infused.

Macular degeneration agents are used to treat neovascularization of the retina, macula, fovea (a tiny pit in the center of macula) and choroid, the layer above the retina. Macular degeneration agents are used in the treatment of eye conditions including:

• Age-related wet macular degeneration
• Macular edema
• Diabetic macular edema
• Diabetic retinopathy
• Myopic choroidal neovascularization
• Macular degeneration with classic subfoveal choroidal neovascularization
• Central serous chorioretinopathy

Most of the side effects of anti-VEGF macular degeneration agents are ocular, while the photosensitizing agent, which is administered intravenously, may cause more systemic side effects, in addition to the ocular side effects. Side effects of macular degeneration agents may include:

Anti-VEGF agents

Ocular side effects:

• Conjunctival hemorrhage (bleeding in the conjunctiva, the clear membrane over the whites of the eye and inner eyelid surfaces
• Eye pain
• Vitreous floaters
• Vitreous opacities
• Cataract
• Increase in intraocular pressure (pressure inside the eye)
• Anterior chamber inflammation (inflammation of uvea, iris and eye’s ciliary muscle, also known as anterior uveitis)
• Eye discharge and irritation
• Conjunctival hyperemia (dilation of blood vessels in the conjunctiva)
• Conjunctivitis (inflammation of the conjunctiva)
• Corneal erosion
• Corneal edema
• Corneal abrasion
• Punctate keratitis (inflammation of the cornea in a pin-point pattern)
• Retinal pigment epithelium detachment (separation of retina’s pigmented epithelial layer from the nerve tissue layer)
• Retinal pigment epithelium tear
• Injection site pain
• Foreign body sensation or abnormal sensation
• Increased tearing
• Blurred vision
• Reduced vision acuity
• Visual disturbances
• Injection site hemorrhage
• Eyelid edema
• Endophthalmitis (inflammation of the intraocular cavities)
• Retinal detachment
• Retinal hemorrhage
• Retinal tear
• Retinal artery block
• Retinal vasculitis (inflammation of retinal blood vessels)
• Vitreous detachment
• Vitreous hemorrhage
• Vision loss
• Posterior capsule opacification (opacity of the posterior side of the clear membrane that encapsulates the lens)
• Systemic side effects:
• Hypersensitivity
• Thromboembolisms (clots in blood vessels)
• Hypertension (high blood pressure)
• Photosensitizing agent
• Ocular side effects:
• Visual disturbances
• Flashes of light
• Severe vision loss
• Light sensitivity
• Conjunctivitis
• Dry eyes
• Itching in the eyes
• Subconjunctival, subretinal or vitreous hemorrhage
• Watery eyes

Systemic side effects:

• Injection site reactions such as rash, or leakage of fluid outside the vein (extravasation)
• Edema
• Hemorrhage
• Inflammation
• Headache
• Back pain during infusion
• Abnormal weakness (asthenia)
• Fever
• Flu-like syndrome
• Atrial fibrillation
• Hypertension
• Peripheral vascular disorder
• Varicose veins
• Eczema
• Constipation
• Gastrointestinal cancers
• Nausea
• Change in levels of white blood cells (leucocytes)
• Anemia
• Elevated liver function test results
• Excess albumin in the urine (albuminuria)
• Joint pain (arthralgia)
• Muscle weakness (myasthenia)
• Reduced skin sensitivity (hypesthesia)
• Sleep disorder
• Vertigo
• Inflammation of pharynx (pharyngitis)
• Reduced hearing
• Pneumonia
• Prostatic disorder

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of some macular degeneration agents include:

Anti-VEGF agents:

• Aflibercept intravitreal (Eylea)
• Brolucizumab-dbll intravitreal (Beovu)
• Pegaptanib sodium (Macugen)
• Ranibizumab (Lucentis)
• Abicipar pegol (pending FDA approval)

Photosensitizing agent:

• Verteporfin (Visudyne)