Macular edema is caused by accumulation in the macula of the liquid exudate that leaves the blood vessels that supply the retina, either because they are abnormal or because their walls are too thin, causing their dilatation and increased permeability. Although it may be the result of ocular surgery, it is usually a complication of different ocular complaints, such as uveitis, different types of retinitis and diabetic retinopathy, venous thrombosis of the retina, etc. The most frequent causes are diabetic retinopathy and secondary edema venous thrombosis.
It should be taken into account that the macula is the central part of the retina and allows you to focus and see in detail any object, allowing activities such as reading, sewing, threading a needle etc.
Consequently, the macular edema symptoms affect the central vision, causing blurred vision and distortion of lines. If not treated properly, the patient may have very limited central vision.
The treatment of macular edema will depend on the cause, the degree of evolution and whether it is focal or diffuse; And will be determined according to the characteristics of each patient. There is the option of a pharmacological treatment with eye drops, or intraocular and periocular injections. Among these drugs, the so-called antiangiogenic agents, which act on the endothelial growth factor, may be highlighted
This factor is responsible for the formation of abnormal blood vessels and increased vascular permeability.
Antiangiogenic drugs reduce the formation of new abnormal vessels (neovascularisation) and prevent fluid loss, although their effectiveness is only temporary.
Other treatment options focus on laser photocoagulation of blood vessel sites where fluid is lost that accumulates in the macula, altering its functionality.
In more severe cases, vitrectomy surgery may be necessary.
Vitrectomy is a surgical procedure in which the transparent gel that fills the eyeball (vitreous humour) is extracted in order to access the retina and treat the abnormal vessels and eliminate possible fibrous bands that can exert traction on the retina, with the subsequent risk of tearing and retinal detachment.
At present, the treatment of choice is intravitreal injection (inside the eyeball) of antiangiogenic drugs. As many injections as the eye requires to control and reduce macular edema should be administered. Intravitreal injections are the only treatment that achieves visual improvements in 30-35% of cases.
Laser treatment allows visual stability but leaves permanent scars so its use should be limited. Finally, vitrectomy should only be performed in cases with confirmed traction and that do not improve with previous treatments.