Laser Photocoagulation for Diabetes Retinopathy
Diabetes mellitus is a well recognised condition that affects millions of people across the globe. It brings with it a plethora of complications that require different modalities of treatment. One such competition that can occur with diabetes is the development of diabetic retinopathy.
The retina forms the back of the eye and is responsible for our vision. Damage to the retina can include damage to the nerve fibres and damage to the blood vessels. Treatment of diabetic retinopathy involves laser photocoagulation and here we shall review this procedure and a little more detail.
What is photocoagulation?
Photocoagulation is a procedure that involves the use of light to coagulate tissues. The light that is emitted onto the tissue is absorbed by it and is converted into heat which results in destruction and coagulation of the protein within that structure.
In diabetic retinal photocoagulation, light is exposed onto the retina which is then absorbed by the tissue and converted into heat. Different tissues absorb different forms of light. For example melanin absorbs red, green and yellow along with infrared wavelengths. Haemoglobin absorbs blue, yellow and green.
In patients with diabetic retinopathy, pan retinal photocoagulation is often performed.
How is laser photocoagulation performed?
Most cases of laser photocoagulation in diabetics performed under local anaesthesia. Topical anaesthetic agents in the form of eye drops are applied to the eye and this can help anaesthetise the cornea. In some cases, general anaesthesia may be required.
Once the patient has been positioned in the operating room, laser is delivered to the retina under microscopic guidance. A fibre-optic cable is utilised to deliver the laser. Slit lamps are used to view the retina through the cornea. A small probe is introduced into the cavity of the eyeball and laser is directed onto the retinal surface. The procedure requires adequate positioning of the patient.
Under direct visualisation using a slit lamp, the laser beam is focused on to the retina. The areas that need to be treated are all exposed to this laser and the procedure usually does not take too much time.
Laser photocoagulation can be of two different types. Focal photocoagulation involves directing the laser on blood vessels on the retina that may be leaking. This helps seal it off completely. Pan retinal photocoagulation, also known as scatter photocoagulation is utilised to stop the growth of new blood vessels that are often seen in diabetic retinopathy. This can involve the widespread use of laser on the surface of the retina, resulting in a rather ‘spotty’ appearance once a procedure has concluded.
Once the procedure has concluded, patients are often asked to rest for a short period of time before being discharged home.
Complications of laser photocoagulation
As a procedure, laser photocoagulation is rather safe when performed in the hands of experts. However, as is the case with any procedure, complications can occur. Some of the common complications include enhanced opacity of the cornea, opacification of the lens, bleeding within the eye, swelling and accumulation of fluid of the macula and visual field defects. Detachment of the retina and accidental burn of the back of the eye may occur. These are of course a rather rare and must be treated straight away.
Other complications of laser photocoagulation include loss of night vision, an alteration in the peripheral and central vision and failure of the procedure itself.
Benefits of laser photocoagulation
The primary benefit of laser photocoagulation is the hindrance of progression of diabetic retinopathy. In essence, this can prevent loss of vision. In other words, it is important for laser photocoagulation to be performed in patients with diabetic retinopathy prior to them developing loss of vision. In fact, clinical studies have shown that performing laser photocoagulation can reduce the risk of developing vision loss from proliferative diabetic retinopathy by 50 to 75% when performed on time.
When undergoing laser photocoagulation, it is important to take into consideration both the risks and benefits of the procedure. The diabetologist and ophthalmologist will only recommend the procedure if they feel that the benefits clearly outweigh the risks of the procedure. In general, it is essential for patients to preserve their vision as long as possible even if they have diabetes. Of course, adequate control of blood sugars through diet and regular exercise is important as well and must be continued. This remains true even after the procedure has been conducted.
Diabetic retinopathy is a well recognised complication of diabetes mellitus and must be dealt with aggressively. Patients have to control the sugars adequately through diet and regular exercise. Laser photocoagulation of the retina is a clinical procedure that helps prevent the growth of new blood vessels that can alter the vision of the patient. The earlier the treatment is administered, the greater the benefit for the patient. Of course, the procedure is not devoid of complications but many a time and benefits clearly outweigh the risks, which is when the procedure is offered in the first place.