Description of the disease
Complications of diabetes that affects the eye are called diabetic retinopathy. At the onset of the disease, the wall of the small vessels becomes abnormally permeable (capillary hyperpermeability) and small dilatations develops (microaneurysms) causing fluid leakage between the tissues (edema) and grease deposits (lipid exsudate). In addition, bleeding and blockages of these vessels also occur, which will cause blood insufficiency (ischemia) on some parts of the retina. Over time, as the process progresses and the blood deficiency of the tissues reaches a certain critical level new blood vessels will be formed (neovascularisation), but these will be abnormal, misplaced and leaking vessels that can lead to additional and more serious complications.
Different lesions are distinguished within diabetic retinopathy, like the edema of the central part of the retina (diabetic macular edema), the growth of new vessels (proliferative diabetic retinopathy) and the complications caused by these formentioned changes (vitreous haemorrhage, tractional retinal detachement). These are important because of needing different therapeutic approach.
One of the most important element of the treatment plan is the management of the general condition (blood sugar, blood fats, blood pressure management, physical activity, healthy diet). The goal of the ophthalmic treatments are to intervene in this gradually deteriorating process and trying to stop this vicious circle, thus preventing a severe and irreversible visual impairment.
Symptoms of diabetic retinopathy
The symtomps are varied according to the stage of the disease from none to sudden vision loss. These are the most common ones:
- blurred or patchy vision
- gradually worsening vision
- sudden vision loss
- eye pain or redness may develop at later stages.
Treatment of diabetic macular edema (DME)
We have two options for treating cystoid macular edema in diabetic retinopathy: injection into the back of the eye (intravitreal injections) and retinal laser treatment (panretinal photocoagulation).
Intravitreal injections
One type of intravitreal injections are the anti-VEGF injections. There are several anti-VEGF drugs, but initially each of them needs to be administered monthly and then at every 2-3 months for an indefined period of time. In certain advantageous cases a few (at least 5) injections are sufficient to permanently eliminate the macular edema, but unfortunately most often the treatment lasts for years due to fluid reoccurence.
Another similar injection therapy are the steroid implants, which are injected into the vitreous within a small absorbable container. They dispense the drug gradually and evenly over several months, which is a clear advantage, but due to its complications (glaucoma or cataract formation), we only use the treatment as a fallback solution in selected cases. Injection treatments are quite effective during their potency period in a large number of patients, but there are cases which don’t respond to treatment. On the other side must be noted that the injections can cause severe complications, such as purulent endophthalmitis, which is a severe, infectious inflammation of the eye that most often leads to permanent vision impairment or blindness. However if hygiene rules are followed, its incidence remains quite low.
Laser treatment
Although the classic laser treatment was utilised for decades, the damage caused by this at the central part of the retina led the ophthalmologists to abandon this treatment option. A new treatment option emerged for diabetic macular edema called micropulse laser treatment, which now can be used as a first choice treatment or as an adjuvant therapy. The latter means if injection treatments fails or if we want to reduce the burden of the frequent administration of injections we can add the micropulse laser therapy.
In case of diabetic maculopathy the Navilas laser system uses micropulse mode to treat the edematous areas of the retina, but with suprathreshold mode we are able to treat the microaneurysms too, so in addition to promoting the absorption of fluid, we also try to prevent the repeated leakage. Laser treatment usually is performed once, but if necessary can be repeated. The micropulse laser treatment can usually be done in one session and is absolutely painless. No external wounds are formed during the treatment, so the dreaded complication of injection treatments, the purulent endophthalmitis, does not occur either. With micropulse laser treatment (find out more) the macular edema can be reduced without any additional tissue damage, which is especially important in areas that are critical for vision. In contrast, the conventional laser is rarely used today to reduce macular edema due to its destructive effect on the tissues.
Treatment of macular microaneurysms
Microaneurysms play an important role in the development of macular edema, from which increased and continuous fluid filtration occurs into the layers of the retina. Closure of microaneurysms can be achieved with laser treatment, but since it is a very small lesion, precision treatment is of paramount importance, otherwise we will sacrifice special areas unnecessarily. It is also possible to treat microaneurysms with conventional devices, but requires a high degree of discipline on the part of the patient, as any small movements can cause permanent vision damage. However with the Navilas laser device this risk can be eliminated: thanks to the eye tracker program and the treatment plans which are made based on images taken just before the procedure the laser will target just the intended abnormal areas.
Treatment of proliferative diabetic retinopathy
In diabetic retinopathy, the severe ischemia of the retina (blood supply deficient) leads to abnormal blood growth, a process called proliferative retinopathy. These abnormal blood vessels often rupture causing vitreous hemorrhage and with further grow leads to tractional retinal detachment, which has an unfavorable visual outcomes even after major surgery.
The easiest way to stop the neovascularization is to perform a proper fundus laser treatment, called panretinal photocoagulation. By treating the most ischemic peripheral parts of the retina, the proportion of areas supplied with blood improves, thereby causing the regression of the abnormal blood vessels. The entire treatment of the fundus usually can be done in 4-6 sessions, but with modern devices (Navilas Laser System or Iridex Pattern Scanning Laser) I can do it in up to 1-2 sessions. Nor can the fact that the patient’s pain sensation is significantly lower be neglected, since compared to conventional devices it is sufficient the application of one-fifth of energy intensity to achieve the effect.