Intravitreal Injections - Benefits and Risks

Introduction

With the advancement in science and technology, novel treatment strategies exist. The majority of them are gaining wide acceptance and popularity across the globe. Intravitreal injections are a treatment entity that focuses on correcting several eye issues. However, these techniques are also associated with certain risks.

What Are Intravitreal Injections?

Intravitreal injections are a part of the treatment for certain ocular defects, in which certain medicines are advised to be injected directly inside the vitreous cavity (fluid-filled space at the inner portion of the eye). Though the concept existed long before, extensive procedure adoption has been reported in recent years. Before advising intravitreal injections for a person, a thorough evaluation of the patient's drug allergy reports, concurrent medications, and relevant medical history should be performed to ensure the safety and effectiveness of the therapy. Doctors prefer intravitreal injections only after considering both the benefits and the anticipated risks associated with the injections. However, the technique is quite sensitive and demands expert doctors to perform it. Improper technique may give rise to ocular complications, which could even endanger a person's vision.

Which Are the Ocular Issues for Which Intravitreal Injections Are Preferred?

Intravitreal injections are employed for a spectrum of ocular issues that significantly compromise the person's vision. Routinely it is preferred for the treatment of the following ocular conditions:

• Age-Related Macular Degeneration (AMD): AMD is an ocular condition where the middle portion of the retina (light-sensitive layer), technically known as the macula, exhibits weakening and deterioration. The affected person encounters trouble in ahead (straight line) vision. The condition progresses over time, remarkably impacting the visual capabilities of a person.

• Macular Edema: It arises when the blood oozes out of the blood vessel and gets gathered in the macular region (central retinal portion). As a result, the macula swells up, giving rise to macular edema and contributing to visual disparities.

• Retinal Vein Occlusion: It is an ophthalmic disease in which the blood flow through the retinal vein, and its sub-branches gets hampered due to clogging or fat accumulation within the vessel. Vision gets notably compromised in retinal vein occlusion.

• Diabetic Retinopathy: It is a consequence of long-standing diabetes (boosted blood sugar level), where the exaggerated blood sugar acts upon the blood vessel walls and makes them leaky. Once the retinal vessels develop diabetic changes, the fluid tends to get buildup in the retina, eventually making the vision unclear and foggy.

• Endophthalmitis: It is precipitated by infectious agents like bacteria and, at times, fungi. These agents induce infection deep in the eye and colonize there. Inflammatory changes like pain and enlargement develop within the eye, affecting the vision.

• Uveitis: Uveitis is any form of inflammatory change that develops in the central layer of the eye (uvea). It often develops due to infections, and the person elicits pain, and eyes appear swollen, redden, and watery.

What Are the Benefits Associated With Intravitreal Injections?

Intravitreal injections offer specific gains when employed for treatment purposes. Some of the relevant gains extended by intravitreal injections include the following:

• Intravitreal infections facilitate the recovery of vision.

• It may check the progression of the disease condition.

• Improvements start getting reflected within hours following intravitreal injection because of the prompt onset of drug action.

• Intravitreal injections enhance the effect of the drugs, as it is directly introduced into the site where it is intended to work.

• As the medicine is injected into the vitreous cavity, it remarkably reduces the likelihood of systemic toxicity resulting from the oral and intravenous (via veins) medicine intake.

• It offers a better prognosis for the disease conditions.

What Are the Risks Associated With Intravitreal Injections?

Though intravitreal injections offer numerous gains, at times precipitate potential complications arising from faulty injection techniques or the side effect of the medicine used for intravitreal injections, some of the potential risks associated with intravitreal injections include the following:

• Infections: Infections always stand out in most treatment interventions. Likewise, intravitreal injection also carries the risk of developing infections in the eye. Ensure that sterile and clean needles are used for puncturing the eye. Infections often elicit eye pain and, if not promptly tackled, harm the eyes considerably.

• Allergic Reactions: Eyes appear reddened and watery, exhibiting inflammatory changes in the event of an exaggerated reaction toward the injected medicine. Sometimes the body's immune cells may trigger some reaction against the drug molecules, which impacts vision.

• Arterial Blockage: At times, intravitreal injections may give rise to clogging within the arteries. Though it is rare, intravitreal injections are capable of precipitating blindness.

• Injury to Ocular Structures: Intravitreal injections, if not done correctly, can result in harm to the eye lens, retina, and other ocular structures. Rarely retinal tears and corneal abrasions develop due to intravitreal injections. At times trauma to the lens led to cataract (faded lens) formation.

• Ocular Bleeding: Unwanted puncturing of the ocular blood vessels can also happen during intravitreal injection, and the person elicits bleeding eyes. In addition, the patient always encounters a foreign body feeling in the eyes. It is disturbing and troublesome.

• Retinal Detachment: This is a grave situation less frequently encountered with intravitreal injection. However, when it develops, it entails immediate medical assistance or will result in loss of eyesight.

• Raised Intraocular Pressure: Intravitreal injection of steroids potentially carries the risk of pronounced eye pressure. In addition, anti-angiogenic drugs also elevate the fluid pressure within the eyes (intraocular pressure).

What Are the Medicines That Are Used for Intravitreal Injections?

Not all medicines are suitable for intravitreal injections. Only a specific category of medicines is employed for the purpose. Some of the drugs that are widely advised in the form of intravitreal injections include the following:

• Dexamethasone, Fluocinolone, and Triamcinolone acetonide (steroid medicine to tackle inflammation).

• Ranibizumab and Bevacizumab (anti-angiogenic medicine that checks abnormal blood vessel growth).

• Aflibercept and Brolucizumab (checks the growth of atypical blood vessels).

• Ganciclovir (an antiviral medicine).

• Clindamycin, Vancomycin, Ceftazidime, and Amykacin (antibiotics to deal with infections).

• Amphotericin B (an antifungal medicine).

Conclusion

Intravitreal injections are widely practiced treatment therapy where the drugs are delivered inside the eye as injections. Unlike systemic administration, intravitreal injections enhance the drug's effectiveness and action and curb the likelihood of systemic toxicity. Though intravitreal injections are known to be associated with certain risks, those complications can be easily tackled with proper technique and prompt treatment. If the procedure is done by properly trained and experienced hands, then that itself will clear off the room for complications.