The dexamethasone is used in combination with the phacoemulsification treatment in treating the diabetic patients who are suffering with non proliferative diabetic retinopathy and macula edema. The phacoemulsification treatment along with dexamethasone implant shows greater results than the phacoemulsification treatment alone.
Contents
Dexamethasone:
Patients who are diabetic and are suffering from macula edema and Non-proliferative diabetic retinopathy are given dexamethasone implant along with phacoemulsification treatment as if it is safer than phacoemulsification treatment alone.
Non-proliferative diabetic retinopathy:
It is also known as background retinopathy. This disease shows its effect in range of mild range to moderate range and at last, it shows a severe stage. It is characterized by microaneurysms in which there are blood-filled bulges present in the arterial wall which are microscopic in size. Later on, the bulges burst and the blood inside them is released near the retina causing problems in the vision of patients.
There are no noticeable changes seen in the initial stage of the disease only there are tiny spots of blood that accumulate in the retina. As the disease increases its severity, there are exudates and gets leaks from the blood vessels. There is bleeding in the veins which are present near the retina and there are abnormalities in the microscopic blood vessels.
Risk factors:
There are various risk factors which increases the risk of getting non-proliferative diabetic retinopathy condition such as
Diabetes:
The presence of diabetes can increase the risk of getting this condition. If there is an increase in the duration of diabetes, then the patient can have a retinopathy condition.
Type 1 and type 2 diabetes mellitus both can cause this disease.
- With the increase in the extent of blood sugar levels, the risk also increases.
- Diseases such as high cholesterol and high blood pressure i.e, hypertension can be risk factors for getting the retinopathy condition.
Kidney impairment :
This condition acts vice versa to the retinopathy condition i.e, non-proliferative diabetic retinopathy can cause kidney impairment and kidney impairment causes non-proliferative diabetic retinopathy.
Sometimes, even the cataract can increase the risk of getting the non-proliferative diabetic retinopathy condition.
Macula edema:
This condition is common which can cause severe loss of vision with Non-Infectious Uveitis (NIU) condition. The intravitreal dexamethasone implant (IDI) is the commonly used corticosteroid for treating uveitis macula edema condition.
It causes blindness in about 2.8%-10% of people who are from the working generation population suffering from the disease.
Mechanism:
The mechanism of action of macula edema is breaking down of inner or outer layer of the blood-retinal layer or it can be disturbances in pumping action of retinal pigment epithelium. The increase in retinal vascular permeability causes extravasation of the fluids, proteins to the retinal interstitium, which is also called the macula. Increased retinal vascular permeability is caused by the constant release of leukotrienes, cytokines, interleukins as well as prostaglandins production along with nitric oxide.
Treatment:
The treatment of NIU is not that easy but is completely challenging. The inflammation of uveitis can be controlled effectively by the use of steroids along with other immunosuppressive agents and other biological products. The decrease in neutrophil transmigration and reduction of cytokines production and production of vascular endothelial growth factor, which is induced by proinflammatory cytokines.
However, there are various routes of administration such as topical, local, periocular as well as the systemic route of administration. The steroids which are given through topical route do not show decrease in inflammation of posterior and intermediate uveitis. The steroids which are given through systemic route of administration have following undesirable effects such as
- Weight gain
- Hypertension
- Steroid-induced diabetes
- Necrosis of hip
- Osteoporosis
- Imbalance in electrolytes
- Disturbance in the gastrointestinal system
- Insomnia
- Psychosis.
Side effects:
- Formation of Cataract
- Increase in Intraocular pressure
However, the effects of systemic routes are prevented by using local routes and the effective local concentration is achieved through this route. Usage of steroids for a long time can cause adverse effects in the patient.
The periocular injections produce short term concentrations causes various serious complications such as
- optic nerve injury
- Retinal vascular occlusion
- Choroidal vascular occlusion
- Hypopigmentation of periocular skin.
- Ptosis
Initially, intravitreal triamcinolone acetonide was used as the off label treatment for treating NIU. Now, the intravitreal dexamethasone implant is used in treatment of NIU as it decreases the various side effects which are produced such as increase in Intraocular pressure, short Intraocular half life and development of cataract.
The dexamethasone is a combination of a biodegradable copolymer of glycolic acid and lactic acid which erodes carbon dioxide and water. The dose of dexamethasone released into the eye is 700 micrograms. The dexamethasone shows its peak activity in the first two months and then there is a slight decrease in the activity of dexamethasone and prolonging action for next six months. The long term use of dexamethasone inorder to reduce the local inflammation and decrease the side effects such as osteoporosis and growth retardation caused by steroidal use in the treatment.
The mechanism of action of dexamethasone is that it binds to the steroidal receptors which are present in the cytoplasm and then modification of DNA expression occurs in the cell nucleus.
Conclusion:
The dexamethasone implant has carved itself a niche in the treatment of Uveitis macula edema and its various other complications and risk factors. Several papers that have suggested the use of dexamethasone implant showed that it has a positive impact on macular edema which is completely undeniable.
The use of dexamethasone implant can be as a single therapeutic agent or with the help of any other component as an adjunct agent in the treatment using systemic therapy. It can be even used as a bridging option while switching between systemic routes.
Uses of dexamethasone:
The usage of dexamethasone implant is properly safe. Scientists who have researched over the uses of dexamethasone proved that it showed good anatomical results and that it has good tolerance ability in treatment to prevent post surgical or ex novo development of macula edema in patients who suffer from diabetic retinopathy.
During a study, a combination of 46 patients, dexamethasone was given to 23 patients along with phacoemulsification and other 23 patients were given only phacoemulsification treatment without the help of dexamethasone implant. The researchers gathered all the information regarding the mechanism and actions of dexamethasone. The action of dexamethasone was determined by the following measures
- Central subfield thickness (CST)
- Best- correct visual acuity (BCVA)
- Intraocular pressure (IOP)
The researchers studied the differences between the two groups in a time period of 3 months. The study showed that there was a difference in mean CST values i.e, the patients who were given only phacoemulsification treatment showed higher value than those of patients who were given phacoemulsification and dexamethasone implant treatment.
The intraocular pressure is in normal range in both the groups, then there is a significant increase in Intraocular pressure in a combination of dexamethasone and phacoemulsification treatment from the second month for the patients than the pressure seen in patients who were given phacoemulsification treatment alone.
Therefore, the combination of dexamethasone implant and phacoemulsification treatment showed better results and is completely safe and favorable treatment for macula edema and non-proliferative diabetic retinopathy which are seen in diabetic patients.
The best way to treat your eyes is to visit your eye care professional and get your eyes checked regularly. He will be able to assess the best method of treatment for your eye ailment. Visit our website Eyemantra. To book an appointment call at +91-8851044355. Or mail us at [email protected]. Our other services include Retina Surgery, Cataract Surgery, and many more.
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