Retinal Lasers, Injections and Surgeries

I.Retinal Laser treatment

                 A laser is an instrument that produces a pure, high-intensity beam of light energy. The laser light can be focused onto the retina, selectively treating the desired area while leaving the surrounding tissues untouched. The absorbed energy creates a microscopic spot to destroy lesions or weld tissues together.

       The only way to tell if you need laser surgery is to have a careful, dilated retinal examination, often followed by special testing including OCT scanning and fluorescein angiography.

Lasers are commonly used to treat the following eye conditions:

Diabetic retinopathy

Diabetes causes circulation problems throughout the body, including the eyes, nerves, and kidneys. The retinal blood vessels are usually like pipes, bringing blood into and out of the back of the eye. In diabetes, however, the vessels may leak, causing the retina to swell and not work properly (diabetic macular edema). Vision is affected when the swelling involves the central vision area. Laser surgery can seal the leaks, thereby preventing further vision loss.

Some patients will have new retinal blood vessels grow to replace some which have closed from the diabetes (proliferative diabetic retinopathy). While this sounds good, these new blood vessels can cause blindness from bleeding and scarring. Laser treatment can often prevent severe vision loss by making these new vessels disappear.

Retinal vein occlusions

The small blood vessels that drain blood from the retina (retinal veins) can sometimes become blocked as part of the aging process. This is more common in patients with diabetes or high blood pressure. A retinal vein occlusion can cause the retina to swell with fluid and blood, blurring central and peripheral vision. Other times, new blood vessels may grow and cause pain with very high pressure inside the eye (neovascular glaucoma). Laser treatment can help reduce this swelling or cause the new blood vessels to disappear.

Age-related macular degeneration

Some people will develop aging changes in the macula, the portion of the retina responsible for our central reading vision. Most will experience the less harmful dry type, which usually causes minimal visual changes. The more severe, or wet type, causes the macula to swell with fluid and blood. Symptoms of wet macular degeneration include painless blurred or distorted vision. Urgent treatment can often prevent or delay vision loss in some patients with this wet type. 

Retinal breaks and detachment

The retina lines the back of the eye like wallpaper. Retinal tears or rips can occur as part of an aging phenomenon, or following cataract surgery or eye injury. Patients will often see cobweb-like floaters or light flashes when a retinal tear develops. Liquid that normally fills the central portion of the eye (the vitreous) can leak beneath the tear, lifting the retina away from the eye wall. This is called a retinal detachment, which can cause blindness if left untreated. Laser surgery around retinal tears is often able to weld the retina to the underlying eye wall. This can prevent or limit retinal detachment.

Central serous chorioretinopathy (CSC)

CSC consists of one or more “blisters” of fluid (serous detachment) beneath the macula. It can cause central blurriness, distortion, abnormal color vision, blind spots, and temporary farsightedness. Although the vast majority of cases will resolve spontaneously, laser photocoagulation is sometimes necessary for persistent lesions.

 

II.Intravitreal Injections

   Intravitreal drug delivery has become a popular method of treatment of many retinal diseases, commonly including AMD, Diabetic Retinopathy, and Retinal Vein Occlusions.  The frequency of Intravitreal injections has significantly increased since the introduction of Anti-VEGF medications.  This is an important procedure that Retina Specialists use on a daily basis, and it is important to master the techniques of effective injections for patient safety and reduction of complications. 

   LUCENTIS® (ranibizumab injection) is a prescription medicine that you may receive from our Retina Specialist. It was approved by the FDA in 2006.

Common Diseases Treated by Intravitreal Injections

1.AMD

2.CSME/PDR

3.Retinal Vein Occlusions

4.Uveitis

5.CME

6.CNVM secondary to multiple retinal diseases

 

III.Retinal surgeries

I.Vitrectomy 

a.Epiretinal membrane

b.Vitreous haemorrhage

c.Macular hole

 

a.Epiretinal Membranes

             An epiretinal membrane is a thin sheet of fibrous tissue that can develop on the surface of the macular area of the retina and cause a disturbance in vision. An epiretinal membrane is also sometimes called a macular pucker, premacular fibrosis, surface wrinkling retinopathy. The retina is a clear film of very delicate tissue that lines the inside of the back of the eye. The macula is in the centre of the retina and it gives us sharp central vision and reading vision.

                                    

                                     Epi retinal membrane

               An epiretinal membrane develops as a result of cellular changes that occur in the back of the eye between the clear vitreous gel that is normally present, and the macula. Normal biological cells derived from the retina and other tissues within the eye become liberated into the vitreous gel and eventually settle onto the surface of the macula. These cells may begin to proliferate into a “membrane.” In many instances this membrane remains very mild and does not have any significant effect on the macula or the person's vision. In other cases, however, the membrane may slowly become more prominent, eventually creating a disturbance in the retina that leads to visual blurring and/or distortion in the affected eye.

                 In the majority of cases, an epiretinal membrane develops in an eye with no history of previous problems. This type of epiretinal membrane is called idiopathic. Occasionally however, an epiretinal membrane will develop in an eye as a result of retinal detachment, trauma, inflammatory disease, blood vessel abnormalities, or other pathological conditions. Most epiretinal membranes are mild and have little or no effect on vision. However, in some cases, the epiretinal membrane may slowly grow and begin to cause mechanical distortion (“wrinkling”) in the macula. This may lead to blurred or distorted vision, which may slowly worsen over time. It typically affects only the center area of vision and does not cause a loss of the peripheral (side) vision.

Management

      Epiretinal membranes can be treated with Vitrectomy surgery. However, not all epiretinal membranes require treatment. Surgery is not necessary if the epiretinal membrane is mild and having little or no effect on vision. There is no non-surgical treatment for an epiretinal membrane.

 

b.Vitreous Hemorrhage

               The vitreous gel occupies approximately 2/3 of the total volume of the eye. It is a semisolid or liquid clear substance that fills the space between the lens in the front of the eye and the retina lining the back of the eye. There are normally no blood vessels within the vitreous gel. Abnormal blood vessels can grow into the vitreous gel in a variety of eye diseases, most commonly diabetic retinopathy. There are, of course, many blood vessels surrounding the vitreous gel. A vitreous hemorrhage occurs when a blood vessel ruptures and bleeds within or near the vitreous cavity.

                                        

                                         Vitreous Hemorrhage

            The initial symptoms of a vitreous haemorrhage are floaters and cloudy vision. Floaters associated with bleeding are described as lines, spider webs, or many dark dots. If the vitreous hemorrhage is very significant, there could be a major loss of vision. Whenever there has been a sudden onset of floaters or visual loss, a prompt, careful retinal examination is necessary both to diagnose the underlying cause of the vitreous bleeding and to determine if any specific therapy is required.

        There are many possible causes of vitreous hemorrhage, including systemic diseases such as diabetes mellitus or sickle cell anemia. Also, with aging the vitreous gel liquefies and separates from the retina, creating a posterior vitreous detachment. Bleeding can sometimes be associated when this occurs. Other causes of vitreous hemorrhage include ocular trauma, retinal tears or detachment, retinal vein occlusion, other vascular abnormalities, tumours, and rarely wet macular degeneration.

 Management

       The most important issue is the prompt evaluation of an eye with an acute vitreous hemorrhage to determine the cause and to determine the status and health of the retina. Diagnostic ultrasonography equipment can be used to study the inside of the eye in situations where there is too much blood to allow for direct visualization of the retina. Depending on the situation, a vitreous hemorrhage may be initially observed to see if the body will absorb it on its own.

           Sometimes vitrectomy surgery is required to remove the blood, improve vision, and to address any underlying retinal disease.

 

c.Macular Hole

        A macular hole is a defect in the center of the macular area of the retina. The macula gives us sharp central vision and reading vision. The very center portion of the macula, called the fovea, is the thinnest portion of the entire retina. It is in this very delicate foveal area that a macular hole can develop.

                                       

                                              Macular Hole

          In most cases, a macular hole develops as a result of anatomical changes that occur spontaneously and not from anything that the patient has done. This type of macular hole occurs most commonly in individuals over 50 years of age and is called an idiopathic macular hole. Occasionally, severe blunt trauma can cause a macular hole. A macular hole can also be seen in a very small percentage of people with retinal detachment, or in conditions that cause severe edema (swelling) of the retina.

   A macular hole causes loss of sharp “straight-ahead” vision and reading vision. In the early stages of macular hole formation, the hole is very small and the central vision may be only slightly blurred or distorted. As the hole enlarges, the vision becomes progressively worse. The hole typically enlarges to a point at which the affected eye can only see the larger letters of an eye chart. A macular hole does not cause complete blindness and does not affect the peripheral (side) vision.

Management

             A macular hole can be treated with Vitrectomy surgery. With current surgical techniques, most macular holes can be repaired with a success rate of about 95%. There is no non-surgical treatment for a macular hole.

       The surgery consists of making very small incisions on the white part of the eye (the sclera). After the vitreous gel is removed, the surgeon peels a very thin membrane called the “internal limiting membrane” from the surface of the retina around the macular hole. A gas bubble is then placed in the vitreous cavity.

 

                                    

       Gas Bubble Face Down

        Newer surgical techniques and instrumentation may allow the surgeon to perform the surgery in some cases through tiny “self-sealing” incisions that do not require sutures. Eye drops or ointments are used for several weeks after surgery to facilitate healing. The gas bubble will gradually go away over several weeks following surgery.

         The most important part of macular hole surgery is the requirement for post-operative face-down positioning. In order for the macular hole to close, the gas bubble must press against the macular hole. Since the macular hole is located directly at the back of the eye, the most effective way to keep the bubble against the hole is for the patient to keep their nose pointed directly downward toward the floor. A variety of positioning aids, such as massage chairs and head-rests, are available to make this requirement more tolerable. The duration of face-down positioning may vary but the average time is 4 to 5 days.

 

II.Scleral buckling

Retinal Detachment

        The retina is the nerve layer that lines the back of the eye. If you think of the eye as a camera, the retina is the film in the camera. A clear gel called the vitreous fills up the inside cavity of the eye and is located just in front of the retina. As one ages, the vitreous gel contracts and liquefies. As this occurs, the vitreous gel may sometimes pull a tear in the retina. Fluid from inside the eye can leak through the tear, and the retina can separate from the back wall of the eye, creating a retinal detachment.

                                 

                         Retinal Detachment

       Retinal detachments occur with a frequency of 1 per 10,000 people per year. It is a serious condition that may lead to blindness if not treated appropriately.  

      Risk factors for retinal detachment include near-sightedness (myopia), history of cataract surgery, family history of retinal detachment, retinal detachment in the other eye, and weak areas in the retina such as lattice degeneration.

     Symptoms of a retinal detachment include onset of floaters, flashing lights, and a “curtain” or area of darkness that may encroach on vision from the side. There is no pain with retinal detachment. You should contact eye doctor as soon as possible if any of these symptoms develop.

Management

    Repair of a retinal detachment is accomplished by bringing the retina back into position and then sealing the hole or tear in the retina. Retinal detachment is almost always treated with some form of surgery. If the detachment is not extensive, it can be treated with laser or cryotherapy (freezing) in the office. Some detachments may also be treated with a procedure called pneumatic retinopexy. This involves the injection of air or gas into the eye in conjunction with laser or cryo. Patients are giving specific head position instructions which allow the bubble to float up against the retina and keep it in position as it heals.

        One of the most common surgical techniques in retinal detachment repair is a scleral buckle procedure. This is done in the operating room where a silicone band is placed around the eye. The band changes the shape of the eye and brings the retina back into contact with the wall of the eye. Cryo or lasers are used to treat around the retinal breaks and other weak areas.

        Vitrectomy surgery also has a role in retinal detachment repair. With this technique, the vitreous gel and any scar tissue is removed from the eye. After the retina is reattached, the vitreous cavity is filled with a gas bubble which helps to hold the retina in position. The bubble generally lasts in the eye for several weeks and is gradually absorbed by the body. In cases of complex retinal detachment, a silicone oil bubble may be used in place of gas. Silicone oil does not dissolve on its own and a second surgery is required to remove it once the retinal tissues are stable.