Interventions for Maculopathy
Intravitreal injections of anti-VEGF drugs for exudative maculopathy
Intravitreal injections of anti-VEGF drugs for exudative maculopathy
La exudative maculopathy is a vascular disease characterized by exudative and hemorrhagic phenomena at the level of the most central part of the retina, the macula. Exudation and hemorrhage cause the formation of a edema within the macular tissue, with distortion of the retinal structure e damage to photoreceptors.
To date, the treatment of choice for exudative maculopathy includes intravitreal administration of anti-VEGF drugs, substances that inhibit the action of VEGF growth factor, the main person responsible for the training of pathological new vessels which cause macular edema.
Anti-VEGF drugs are administered directly into the eye cavity using a microsurgical procedure known as intravitreal injection. This allows the drug to be released near the retina, so that the therapeutic action has the maximum efficacy at the retinal level and lower risk of systemic side effects.
For most patients, treatment with anti-VEGF drugs must be repeated over time as it does not result in definitive recovery. Drug addiction can lead to a high degree of stress in patients; despite this negative aspect, however, we would like to emphasize that this therapy offers an important perspective of preservation of vision and then maintenance of the quality of life.
Intravitreal injection is an outpatient procedure that requires a sterile environment and for this reason it is performed in operating room, prior eye preparation with mydriatic eye drops, disinfectants e anesthetics. The injection procedure has a duration of approx 5 minutes and for this phase the patient can ask to undergo a deep sedation.
Il postoperative it is generally devoid of particular hassles. For a few days the patient has to instill antibiotic eye drops e cortisone in the treated eye and, in the rare event that pain occurs, it can resort to painkillers. Complications and side effects they are extremely rare, but it is good that the patient is always informed before undergoing the procedure.
Treatment with anti-VEGF drugs should be administered as early as possible in case of the presence of pathological new vessels. At first the patient undergoes the so-called loading phase, which consists of the administration of three intravitreal injections one month apart. This phase is followed by the maintenance phase, which consists in repeating the intravitreal injection as soon as the therapeutic effect is about to end.
La duration of the therapeutic effect is monitored through the checkups and depends on both the drug and the patient, but can usually range from 6 to 12 weeks. Maintenance therapy is essential to safeguard the survival of photoreceptors and preserve a good degree of visual quality over time; on the contrary, the interruption of the treatment, where it is still necessary, leads to the rapid deterioration of the photoreceptors of the macula and irreversible loss of central vision.
Medicines with longer therapeutic duration or with therapeutic effect definitive are a much felt need by the community of patients and ophthalmologists and fortunately scientific research and clinical studies today seem to be able to promise for anti-VEGF drugs (but not only) a further positive evolution in this sense.
The possibility of treating the drusen of the atrophic maculopathy using a “subthreshold” laser treatment is a more than dated reality. In the past years, the highly positive results found in numerous sporadic studies have been contrasted by multicentre studies which have instead shown a poor efficacy of the treatment. The latter reported a possible incidence of complications, such as the onset of post-treatment choroidal neovascularization (CNV).
In reality, the apparently satisfactory results reported were the result of an inappropriate study protocol that has never clearly established:
LASER SUBTHRESHOLD
- The selective criteria necessary for the enrollment of patients;
- The treatment parameters (eg diameter of the laser spots, intensity of the laser emission expressed in milliwatts, persistence of the laser irradiation expressed in milliseconds, etc.);
- The precise identification of the lesions (drusen) to be treated The limitations listed above have been further amplified by the difficulty deriving from having to carry out the infrared laser treatment (810 nm) not visible to the specialist during the treatment. The difficulty during the "clinical trials" consisted in carrying out a treatment that was effective, but without exceeding the amount due.
Some colleagues have obviated the limitations related to this treatment by using as a reference parameter the morphological variations found in the autofluorescence in correspondence with the treated retinal areas.
A new generation of lasers (Pascal EpM®) has recently been developed which, using a “modified algorithm”, allows to focus the energy emission exclusively on the retinal pigment epithelium (RPE). This has opened today a concrete possibility of successfully carrying out this type of treatment, depriving it of the side effects that had occurred in the past as a result of inappropriate treatments. This new, emerging technology seems to be the ideal prerequisite for guaranteeing in this way the execution of a useful and reproducible result in a constant and effective way over time.
2RT laser for atrophic maculopathy
La atrophic maculopathy is characterized by the presence of friendly at the level of macula, the most central part of the retina. The formation of drusen is a phenomenon that originates in the loss of efficiency of the metabolism and other vital functions of the retinal cells, consequent to theaging of the retina same.
Over time, such inefficiency leads to a slow but progressive atrophy of photoreceptors. In some patients the drusen increase in number and size resulting in confluent drusen, which physically separate the photoreceptors from their source of oxygen and nutrition, thus helping to accelerate the atrophy process. Over the years, atrophic maculopathy can progress to the terminal stage of geographic atrophy (GA), in which we have the irreversible loss of central vision.
In some cases, the presence of confluent drusen can lead to a phenomenon of localized inflammation able to trigger a series of mechanisms that lead toonset of exudative maculopathy.
There is currently no approved cure for atrophic maculopathy, however treatment with the nanosecond sub-threshold laser (2RT laser) has proven to be capable of slow the progression of atrophic maculopathy towards the advanced stages of geographic atrophy or exudative maculopathy. The treatment is effective in 76% of patients correctly selected and without reticular pseudodrusen.
The efficacy of the 2RT laser was validated by the randomized multicentre clinical trial LEAD, the results of which were published in the American scientific journal Ophthalmology in 2018 and 2021.
The nanosecond laser is capable of generating an incredibly short duration beam of light and extremely low energy, far below the energy threshold that could be harmful to the delicate retinal tissue. Applied to the macula, the laser stimulates the production of metalloproteinases, enzymes that promote tissue regeneration of the retinal pigment epithelium, Bruch's membrane and choriocapillary. The treatment induces a biological restorative response, resulting restoration of the functionality of the visual cycle.
Retrospective studies on the treatment of patients with atrophic maculopathy with the nanosecond laser performed at our Center confirmed the results of the LEAD study, highlighting morphological and functional improvements.
