Vitreous hemorrhage

Vitreous hemorrhage occurs when blood leaks into the vitreous fluid in the eye. This vitreous fluid helps the eye keep its shape and is normally clear, allowing light from outside the eye to pass through it to reach the retina. Leaking blood most commonly comes from the blood vessels at the back of the eye. This is more likely to happen if the blood vessels have been damaged (by injury, for example) or are particularly fragile (due to certain diseases).

In order for us to see clearly, the vitreous fluid must be clear. If the vitreous fluid is cloudy or filled with blood, vision will be impaired. This impairment ranges from symptoms in which small “floating” objects are visible and vision is impaired, to vision becoming completely dark (sometimes with a reddish shade).

Usually only one eye is affected. Although very alarming, once the bleeding has been treated, many cases resolve and vision is restored to where it was before.

The most common causes, accounting for about 90% of all cases of vitreous hemorrhage, are:

• Bleeding from new, abnormal blood vessels that form in advanced diabetic retinopathy
• Bleeding caused by possible retinal detachment
• Eye injuries (most common cause in younger people)

Bleeding inside the eye can occur due to:

Abnormal blood vessels that grow because the back of the eye is deprived of oxygen. They are fragile and bleed easily. Conditions in which this can occur include:

• Diabetic retinopathy (most common cause)
• Macular degeneration
• Retinal vein occlusion

Normal blood vessels that are damaged. They can be damaged by:

• Posterior vitreous detachment, retinal detachment
  
• Retinal macroaneurysm – usually related to hypertension, atherosclerosis and smoking.
• Blunt injury – sudden compression of the eye
• Penetrating injury – this will cause bleeding all over the eye. It does not always cause severe eye pain.
• Subarachnoid hemorrhage, which can increase pressure in the retinal veins, causing them to bleed.
• Eye surgery, especially if it involves the inside of the eye.

Blood from behind the retina gets into the eye. This is the least common cause of vitreous hemorrhage. It can result from:

• Tumors behind the eye (Ocular tumors are rare, the most common type is ocular melanoma).
• Fragile new blood vessels behind the retina.

During the ophthalmological examination you will be examined with a slit lamp to look in detail inside the eye. The slit lamp will allow the doctor to see if there is blood in the vitreous.

Finding the source of the bleeding may be possible with the slit lamp, although if there is a lot of blood in the vitreous fluid, this leads to a blurred vision and therefore it can be difficult to know what has happened. In this case you may need an ultrasound scan of the eye. Ultrasound can detect many causes of vitreous hemorrhage, including posterior vitreous detachment, retinal tears and detachments, tumors and foreign objects.

Sometimes an angiogram is necessary. This test shows the blood vessels in the back of the eye. This can be useful if there are abnormal blood vessels, such as those caused by diabetes.

Symptoms of light bleeding (most bleeding is light) are floating particles, cobwebs, haze and shadows in the eyes. Vision may have a red shade. Symptoms most commonly affect one eye, although both eyes may be affected.

More severe bleeding causes vision impairment, sometimes with dark spots or streaks.

The most severe bleeding causes loss of vision, which can be complete, leaving vision blurred red or black. For most people, this is extremely alarming, especially as it tends to occur very quickly without clear explanation.

Treatment of vitreous hemorrhage varies depending on the cause. The aims of treatment are:

• finding the source of bleeding
• stop the bleeding
• repair any damage to the retina before it leads to permanent loss of vision.
• restoration of normal vision.

Once the source of the bleeding has been identified, treatment will depend on the cause. If there is not much blood in the vitreous and the source of the bleeding can be seen, then it is treatable. This means laser treatment for the bleeding vessels and any other abnormal vessels and repairing any tears in the retina.

If blood in the vitreous obstructs vision, a procedure called vitrectomy may be needed to remove the vitreous. Your doctor will perform a vitrectomy if the back of your eye cannot be seen or if the view isn’t good enough to treat the bleeding there safely. Afterwards, to fix the retina, the gap may be filled with a special gas and at the end of the surgery, with silicone oil, which must be removed in a subsequent surgery. The vitrectomy surgery can take more than one hour and is performed under local anesthetic under a microscope.

Specific treatments:

Laser photocoagulation is the common treatment for fragile abnormal vessels. Treating them stops bleeding and prevents further bleeding. Laser photocoagulation is also used to repair retinal damage, including retinal detachments.

Anti-VEGF injections aim to shrink the abnormal vessels that have formed in the eye. They are sometimes used in patients with diabetes, in addition to other treatments such as laser photocoagulation and vitrectomy, to reduce bleeding.

Vitrectomy is the complete removal of the vitreous fluid along with the membrane surrounding it. This is done when there is so much blood in the vitreous that it is impossible to diagnose and treat the cause. Vitrectomy is sometimes performed if the blood in the vitreous is draining very slowly and vision remains impaired.

Waiting is usually the best option once the bleeding has stopped. Most cases of vitreous hemorrhage do not require vitrectomy. The blood slowly clears from the vitreous, allowing light to pass through it again. If the basic vision is not damaged, then normal vision will be restored.

You may experience pain in your eyes and your vision may be blurred for a few days. Your eye may be swollen, red or sensitive for several weeks.

Vitreous hemorrhage, depending on its causes, can be complicated if there is no treatment or follow-up by the doctor. Conjunctival organization of the vitreous with the formation of yellowish-white flanges and membranes can lead to opacification of the vitreous. Hemolytic glaucoma and retinal siderosis are other possible complications of vitreous hemorrhage.

Vitrectomy surgery, although very safe, can have some risks, like any other eye surgery: infection, hemorrhage, cataract, increased intraocular pressure (eye pressure), retinal detachment, decreased visual acuity, etc.

Patients should be followed up periodically to monitor the elimination of vitreous hemorrhage. If the patient has systemic diseases, such as diabetes, follow-up with the family doctor or specialist should also be recommended. If adequate view to the posterior pole is not possible, patients should be reassessed every two to three weeks with ocular ultrasound to rule out a retinal tear or detachment.

You will be recommended:

• avoid intense activity for at least a few days, as this could dislodge clots and trigger new bleeding.
  
• sleep with your head elevated, as this allows the blood in the vitreous to settle at the back of the eye, out of the line of sight
  
• treatment will be prescribed, which the patient will follow at home
  
• touching the operated eye with a handkerchief or a dirty hand must be avoided
  
• bathing is allowed, but be careful not to get water in the operated eye
  
• pressing or rubbing of the operated eye must be avoided
  
• wear sunglasses during the day
  
• you may need to wear an eye patch or eye shield for a few days.