Retinal Vascular Disease
The retinal vasculature comprises an intricate network of arteries, capillaries and veins that supply the inner retina with oxygen and important nutrients, as well as removing byproducts of retinal metabolism. Diseases affecting the retinal vessels, such as hypertension and diabetic retinopathy, commonly involve other vessels throughout the body in a similar manner. Retinal examination therefore provides the ophthalmologist with a unique perspective, allowing direct inspection of the health of a patient’s microvasculature, which not only guides their specific ocular treatment, but also through feedback to the patient’s general practitioner may allow lifestyle and therapeutic changes to improve the patient’s overall systemic health.
Examples of important conditions affecting the retinal vasculature include:
- Hypertensive retinopathy
- Retinal vein occlusion
- Retinal artery occlusion
- Diabetic retinopathy
Symptoms
Retinal vascular conditions generally involve a blockage of blood flow, leakage of fluid, or rupture of a retinal vessel (i.e. artery, capillary or vein), all of which can result in loss of vision. The visual disturbances experienced with retinal vascular diseases are variable, due to the specific nature of the vascular insult and the extent to which the blood supply is compromised. Symptoms can manifest as blurring of central vision or a loss of visual field, and may occur abruptly (minutes to hours) with subsequent spontaneous recovery – as in amaurosis fugax due to a retinal artery embolus; or cause insidious permanent visual loss over years, as occurs in some patients with diabetic maculopathy.
Acutely, retinal vascular disease is often painless, although patients with hypertension may complain of a headache and feel systemically unwell. Also, patients with a condition called temporal arteritis may experience several days to weeks of temporal headache, scalp tenderness, as well as jaw pain when chewing and generalized lethargy and myalgia. Patients with symptoms of giant cell arteritis require urgent assessment and treatment, and should present to their ophthalmologist, general practitioner or their local hospital emergency department for review.
Treatment
Treatments for retinal vascular disease focus on restoring retinal perfusion, managing complications of intra-retinal fluid leakage and may require surgical procedures to clear haemorrhage from within the eye.
Successful treatment of retinal vascular disease is dependent on identifying and correcting any underlying systemic causes, especially high blood pressure, diabetes and elevated cholesterol, and involves shared care between the patient’s general practitioner and their treating ophthalmologist.
In patients with diabetes and retinal vein occlusion, vision maybe lost due to swelling of the macula. Traditionally, laser has been used to allow targeted treatment to areas of vascular leakage, identified by fluorescein angiography. Today however, macula swelling is more effectively treated with an injection of an anti-vascular endothelial growth (anti-VEGF) factor agent, such as ranibizumab, aflibercept or bevacizumab or an intraocular steroid injection. Although each of these drugs work well to resolve macula swelling, they each have a limited duration of action and therefore patients often require repeated injections to help decrease their macula swelling and maintain their visual gains.
Growth of new blood vessels within the eye occurs in patients who have chronic impairment of their retinal blood supply. These changes maybe observed in those with more advanced diabetic retinopathy, or a more severe retinal vein or artery occlusion. Both anti-VEGF and laser treatments can help regress these abnormal new vessels and each treatment has its advantages and disadvantages, which will be explained by your ophthalmologist. Occasionally, patients with retinal vascular disease experience haemorrhage into the eye, which causes a sudden increase in floaters and loss of vision. Often this is due to rupture of abnormal fragile new blood vessels, such as those sometimes found in patients with advanced diabetic retinopathy or severe past retinal vein and artery occlusions, but vitreous cavity haemorrhage may also be seen in those with chronic hypertension and rupture of a retinal artery aneurysm. In these instances, surgery, in the form of a vitrectomy maybe advised to remove the haemorrhage to allow diagnosis and further treatment.
Vitrectomy surgery involves the introduction of microscopic instruments into the back of the eye through the white part of the eye, termed the sclera, and controlled removal of haemorrhage from within the eye. Application of retinal laser treatment and intraocular medications is also possible during this procedure.
Outcomes
The prognosis for patients suffering from retinal vascular disease is dependent on its specific cause, severity and duration. To obtain the best visual and ocular health outcomes, it is important that patients suspected of retinal vascular disease, see their ophthalmologist early to obtain an accurate diagnosis and to begin prompt treatment. Good visual outcomes are possible for many retinal vascular diseases assuming timely ocular and systemic treatment.
Complications of treatment
Complications from the treatment of retinal vascular disease, whether it be laser surgery, intraocular anti-VEGF or steroid injections, or from vitrectomy surgery are low.
Below are listed some important complications associated with each treatment:
1. Retinal laser
- Blurring of vision
- Loss of visual field
- Trouble seeing at night
- Eye pain
- Impairment of accommodation
- Photosensitivity
2. Intraocular anti-VEGF injections
- Infection
- Blurring of vision
- Subconjunctival haemorrhage
- Elevated intraocular pressure
- Eye pain
- Cerebrovascular accident
3. Intraocular steroid
- Infection
- Blurring of vision
- Subconjunctival haemorrhage
- Elevated intraocular pressure
- Cataract
- Eye pain
4. Vitrectomy surgery
- Infection
- Cataract
- Elevated intraocular pressure
- Retinal detachment
- Vitreous haemorrhage
- Subacute loss of vision due to air, gas or silicone oil within the eye
What to expect after surgery?
In most instances, retinal vascular disease is treated with procedures performed in the office, such as retinal laser or an intraocular injection. These procedures maybe performed on the day of initial consultation to avoid delay in treatment and are performed with local anaesthesia only. Vision in the treated eye is generally decreased temporarily following both procedures and the treated eye may occasionally be covered with an eye pad for several hours afterwards. Due to reduced vision in the treated eye, it is important that patients likely to require treatment for their retinal vascular disease are accompanied by a relative or friend to assist their return home.
Ocular discomfort after a retinal laser or intraocular injection is usually self-limiting and responds well to simple analgesia with non-steroidal anti-inflammatory medications or paracetamol. Occasionally, following an intraocular injection procedure, patients may experience ocular surface irritation, with stinging and/or burning in the eye. These symptoms often last less than 24 hours and are due to residual betadine or chlorhexidine in contact with the conjunctival surface. Patients with ocular surface irritation are advised to use ocular lubricant drops for relief, as well as simple oral analgesia. Importantly, any symptoms of decreased vision or ocular pain not improving within the first 24 hours of treatment require urgent review and patients should contact the Terrace Eye Centre immediately if concerned.
A vitrectomy procedure on the other hand, is a more complex treatment performed in a hospital or day surgery setting. Most vitrectomies are performed under a local anaesthetic and patients return home on the day of their surgery. A post-operative review is routinely scheduled for the day following surgery and an eye pad and shield covers the eye until review. Following day one review, patients will be given instructions about their post-operative drops and other medications, posturing, levels of activity – including driving, measures to keep their eye clean and further follow-up appointments. Importantly, patients who have had the insertion of an air or gas bubble into their eye as part of their vitrectomy must not fly or ascend to higher altitudes, as such ascents can raise the intraocular pressure to dangerous levels and cause permanent visual loss. Pain is generally minimal following a vitrectomy and vision progressively improves over the first post-operative month. Any complaint of worsening pain or decreased vision is abnormal and patients with these symptoms are advised to contact the Terrace Eye Centre for review.
Summary
Retinal vascular disease is an important cause of visual loss, which requires prompt diagnosis and treatment. Common causes of retinal vascular disease include hypertensive retinopathy, retinal vein and artery occlusions and diabetic retinopathy. Treatment of retinal vascular disease requires both specialised ocular and systemic care, with close collaboration between a patient’s primary care physician/general practitioner and their ophthalmologist to achieve their best health outcomes.