Image of a cup of coffee obscured by patches of vision loss

What’s wrong with this picture?

For people with reduced or no vision, even everyday tasks can become difficult. The ability to work or have an active social life may be affected, and people with vision loss may have to rely on family and friends for activities such as shopping, cleaning and dressing. It’s no surprise then that reduced or lost vision can cause increased social isolation, depression and anxiety disorders.1

A survey published in a specialist medical journal found that 88% of respondents believe good eyesight is important to overall health and wellbeing. Nearly 50% believe losing their eyesight would have a greater impact on their everyday lives than losing a limb, their memory, hearing or speech.2

Retinal diseases, such as neovascular age-related macular degeneration (nAMD) and diabetic eye diseases, are some of the main causes of vision impairment and blindness.3 They affect the retina, a thin layer of light-sensitive cells and nerve cells located in the back of the eye, which is involved in sending information to the brain to enable sight.4

Different conditions, similar symptoms

Retinal diseases are caused by unique changes in the eye. When a person has nAMD, new and abnormal blood vessels grow uncontrollably under a part of the retina called the macula, which is responsible for clear, central vision. These new vessels can break, leaking blood or other fluids into the macula. This can result in swelling, bleeding and fibrosis (scarring), and ultimately vision problems.5,6

While the biology behind each retinal disease is unique, some of the symptoms they cause are common among each of them, and can have a major impact on daily life.


Dark spot in central vision

Geographic atrophy (GA) is an advanced form of AMD. In a person with GA, visual clarity can still be good if the macula is spared, but clarity will decrease if GA spreads to other parts of the retina. People with GA can experience difficulty in driving, shopping, reading, finding street signs and other social and manual activities.7 Additional anxiety and stress can be caused by the expectation that the vision loss associated with their condition is likely to get worse over time.7 Currently there are no approved or effective medicines to treat or prevent the progression of GA.8

Image of a landscape obscured by a dark spot in the centre
A dark spot, called a central scotoma, may appear in the centre of a person’s vision, affecting their ability to see straight ahead.

Patches of vision loss

In diabetic eye diseases, like diabetic retinopathy (DR) and diabetic macular edema (DME), uncontrolled high blood sugar levels can lead to damage of the tiny blood vessels (the capillaries) in the retina. These vessels may leak blood and fluid into the retina leading to swelling and blocking blood supply to some areas of the retina.9 In DME, an advanced form of DR, bleeding can cause the appearance of ‘floating’ spots. Without prompt treatment, repeated bleeding increases the risk of permanent vision loss.9 Effective screening and management for people with diabetes is required to monitor for these symptoms, and to prevent vision loss.10

Image of a cup of coffee obscured by patches of vision loss
Blind spots or dark patches may appear in a person’s central or side (peripheral) vision, impairing their ability to see clearly.

Blurry or distorted vision

Retinal vein occlusion (RVO) is a blockage of the blood supply to the retina, which ‘starves’ the retina of oxygen so that it is unable to send visual information to the brain. When a retinal vein is blocked, it can no longer drain blood from the retina, which leads to haemorrhages and fluid leakage into the retina, causing swelling.11,12 It is usually one of the four smaller ‘branches’ of the main, central retinal vein that becomes blocked. This is referred to as a branch retinal vein occlusion (BRVO), and only part of the retina is affected. Rarer central retinal vein occlusions (CRVO) are likely to cause more severe sight loss. A key symptom of RVO is the sudden, painless loss of sight in one eye, which may become dimmer or more blurred over the course of several hours or days.12

Blurred image of a phone in a person’s hand
Things like photos and other objects may not appear as clear as they have before, becoming blurry and distorted.

Wavy lines

Myopic choroidal neovascularization (myopic CNV) is a common, vision-threatening complication of severe short-sightedness, also known as pathological myopia.13 When a person is severely short-sighted, their eyes grow too long from back to front, which leads to areas of the retina that are prone to breaking. As a result, new abnormal blood vessels can grow underneath the retina, leaking blood and fluid, causing damage and vision loss.14 A key symptom of mCNV is metamorphopsia, where vision is distorted and straight lines appear bent, crooked or irregular.

Image of a man using a pedestrian crossing where the lines of the crossing appear to be wavy
Lines that should appear straight, like the lines of a pedestrian crossing, may look wavy or warped.

Getting an annual eye exam is the best way to detect any changes in vision. A dilated retinal examination will help to diagnose any retinal diseases. If you’d like more information on these and other retinal diseases, talk to your optician or visit www.retina-international.org/.

References

  1. Park SJ, Ahn S, Woo SJ, et al. Extent of Exacerbation of Chronic Health Conditions by Visual Impairment in Terms of Health-Related Quality of Life. JAMA Ophthalmol. 2015; 133:1267-1275.
  2. Adrienne WS, Bressler NM, Ffolkes S, et al. Public Attitudes About Eye and Vision Health. JAMA Ophthalmol. 2016; 134:1111-1118.
  3. Flaxman SR, Bourne RRA, Resnikoff S, et al. Global causes of blindness and distance vision impairment 1990-2020: a systematic review and meta-analysis. Lancet Glob Health. 2017; 5:1221-1234.
  4. Mayo Clinic. Retinal Diseases. [Internet; cited November 2018].
    Available from: https://www.mayoclinic.org/diseases-conditions/retinal-diseases/symptoms-causes/syc-20355825.
  5. NHS Choices. Macular Degeneration. [Internet; cited November 2018]
    Available from: http://www.nhs.uk/Conditions/Macular-degeneration/Pages/Introduction.aspx.
  6. Kellogg Eye Center. AMD. [Internet; cited November 2018].
    Available from: http://www.kellogg.umich.edu/patientcare/conditions/amd.html
  7. Sacconi R, Corbelli E, Querques L, Bandello F, Querques G. A Review of Current and Future Management of Geographic Atrophy. Ophthalmology and Therapy. 2017; 6:69-77.
  8. Amdbook. Geographic Atrophy [Internet; cited November 2018].
    Available from: http://www.amdbook.org/content/geographic-atrophy-0.
  9. National Eye Institute. Facts About Diabetic Eye Disease. [Internet; cited November 2018].
    Available from: https://nei.nih.gov/health/diabetic/retinopathy.
  10. Yau JWY, Rogers SL, Kawasaki R, et al. Global Prevalence and Major Risk Factors of Diabetic Retinopathy. Diabetes Care. 2012; 35:556-564.
  11. National Eye Institute. Central Retinal Vein Occlusion. [Internet; cited November 2018]. Available from: https://www.nei.nih.gov/faqs/retina-retinal-occlusion.
  12. Macular Society. Retinal vein occlusion. [Internet; cited November 2018]. Available from: https://www.macularsociety.org/retinal-vein-occlusion.
  13. LUCENTIS. What is mCNV (Myopic Chorodial Neovascularization). [Internet; cited November 2018].
    Available from: https://www.lucentis.com/mcnv/learn-about.html.
  14. Fort Lauderdale Eye Institute. Choroidal Neovascularization. [Internet; cited November 2018].
    Available from: https://flei.com/choroidal-neovascularization/.

Tags: Ophthalmology