Macular degeneration and cataracts surgery explained

Age-related macular degeneration (AMD) is an eye disease caused by deterioration of the macula — a small area in the centre of the retina (the light-sensitive part of the eye). The macula is responsible for making sure we can see things in front of us (‘central vision’) clearly and in detail1. If you have AMD, you may have trouble seeing clearly.

Cataract occurs due to a clouding of the lens in the eye, which is otherwise transparent. This opacity prevents light from passing through, leading to cloudy or blurred vision. Cataract is very common in older people and can be treated effectively with surgery2.

In some people, macular degeneration and cataracts occur together, leading to significant impairment in eyesight. If this is the case, your doctor may discuss surgical options with you, including cataract surgery. However, there are a number of factors they will consider before recommending you for the procedure.

To better understand these factors, it is important you first understand each condition and how it might affect you.

Types and symptoms of macular degeneration

People with AMD may find it difficult to see the fine details of things in front of them, and commonly have a blurred area in the centre of their visual field. For example, this might cause a person to see the numbers on a clock face but not the hands. Over time, the size of the blurred area increases, while objects appear faded, and blank spots develop in the central vision. This can interfere with daily activities such as reading, writing, cooking, and driving. It can also make it challenging to recognise faces and see fine details in objects,3 such as text on the page of a book.

What to do if you have ocular hypertension

It’s important to have your eyes tested every two years (or more often if advised) — and people with a family history of glaucoma may be advised to have annual eye tests. The optometrist can track the pressure inside your eyes and your visual fields over time, which means that any small changes can be picked up early.

A particularly good way of assessing if the pressure in the eye is causing any issues is through OCT tests: a hospital-grade scan that allows the optometrist to see a 3D cross-section of the nerve fibres at the back of the eye.

There are two types of AMD: ‘dry’ and ‘wet’. The dry form is more common and occurs because the macula tissues become less efficient at processing waste products with age. Tiny clumps of protein waste products form (‘drusen’) and macula tissue dies, which over time causes thinning of the macula. This results in a gradual loss of central vision. Wet AMD is the less common but more serious form of the disease. It occurs due to growth of abnormal blood vessels under the retina, which leak blood and cause scarring. Loss of vision occurs more quickly with wet AMD compared to the dry form of the condition4.

Types and symptoms of cataract

A cataract develops due to normal wear-and-tear in the eyes of older people. Clumps of protein cloud the lens in the eye, which is normally clear. This leads to cloudy or blurry vision, like looking through a frosted window or dirty windshield.

In most people, cataracts develop slowly and do not affect eyesight in their early stages. However, as a cataract grows in size, it can start interfering with vision and quality of life. Symptoms include cloudy vision, halos around lights, fading of colours, and difficulty with night vision. You may also experience sensitivity to bright lights and glare.

Activities such as reading may require bright lights, stronger eyeglasses, or magnifying lenses. If you have cataracts and wear glasses or contact lenses, your prescription is also likely to change more frequently5.

There are three types of cataracts:

Nuclear cataracts affect the centre of the lens and can make it difficult to distinguish colours

Cortical cataracts consist of wedge-shaped opacifications on the outer edge of the lens

Posterior subcapsular cataracts form at the back of the lens. They interfere especially with reading and cause halos to form around lights. This type of cataract tends to progress faster than the other types5.

The connection between macular degeneration and cataracts

Age-related macular degeneration affects the macula in the back of the eye, while cataracts affect the lens towards the front of the eye. Both conditions are age-related and contribute to impaired vision, especially in people older than 60. It is possible to have one without the other; they are two separate eye diseases with different causes. However, they share more than one common risk factor, and sometimes occur concurrently, which can have a considerable impact on your vision.

Is it safe to have cataract surgery with macular degeneration?

Cataract can be easily treated with surgery, but there are some conflicting reports about the relationship between cataract surgery and AMD. The traditional view is that cataract surgery could increase the risk of AMD progressing. However, more recent studies have shown that patients with mild to moderate macular degeneration and moderately severe cataract can benefit from cataract surgery6.

Whether cataract surgery should be performed in an individual with AMD is a complicated decision. Your ophthalmologist will first need to ascertain which of the conditions is the primary cause of your vision worsening. In some people with advanced AMD, the retina may be damaged to such a degree that cataract surgery will not noticeably improve vision. In other people, cataract surgery can significantly improve vision and quality of life6.

Large multi-centre studies have shown that there is no increased risk of progression to the advanced (wet) form of AMD in patients who undergo cataract surgery7, 8. Moreover, nutrients such as vitamin C, vitamin E, zinc, lutein, and zeaxanthin have been found to substantially reduce the risk of AMD progressing to advanced stages9.

Complications from cataract surgeries are rare. In patients with AMD, the clinical approach may simply need to be altered and some special precautions taken. There is usually no need to stop treatment for macular degeneration: Anti-VEGF injections for AMD can continue in people who have, or who have undergone cataract surgery10. These are injections that reduce the growth of new blood vessels beneath the macula.

Cataract surgery itself is a relatively simple procedure and takes less than an hour to perform. It is usually done on an outpatient basis and there is some mild discomfort, scratchiness, and blurring of vision for a few days afterward. Vision can begin to improve as quickly as a few hours after the procedure, but it can take up to two weeks for eyesight to become more sharply focused, and up to eight weeks for the eye to heal completely.

Want to learn more about treating cataracts and macular degeneration? Head to our cataracts and macular degeneration pages or book in for a chat with one of our friendly Specsavers opticians.

References

1. American Macular Degeneration Foundation. (no date). What is macular degeneration? [Online]. Available at: https://www.macular.org/what-macular-degeneration [Accessed 2 September 2019].
2. National Eye Institute. (no date). Facts About Cataract. [Online]. Available at: https://nei.nih.gov/health/cataract/cataract_facts [Accessed 2 September 2019].
3. National Eye Institute. (no date). Facts About Age-Related Macular Degeneration. [Online]. Available at: https://nei.nih.gov/health/maculardegen/armd_facts [Accessed 2 September 2019].
4. American Academy of Ophthalmology. (no date). What is Macular Degeneration? [Online]. Available at: https://www.aao.org/eye-health/diseases/amd-macular-degeneration [Accessed 2 September 2019].
5. Mayo Clinic. (no date). Cataracts. [Online]. Available at: https://www.mayoclinic.org/diseases-conditions/cataracts/symptoms-causes/syc-20353790 [Accessed 2 September 2019].
6. Wong, TY. Cataract surgery in patients with cataract and age related macular degeneration: do the benefits outweigh the risks? British Journal of Ophthalmology 2000;84:1337–1341 [Online]. Available at: https://bjo.bmj.com/content/bjophthalmol/84/12/1337.full.pdf [Accessed 2 September 2019].
7. Armbrecht AM, Findlay C, Kaushal S, Aspinall P, Hill AR, Dhillon B. Is cataract surgery justified in patients with age related macular degeneration? A visual function and quality of life assessment. British Journal of Ophthalmology Volume 84, Issue 12. [Online]. Available at: https://bjo.bmj.com/content/84/12/1343 [Accessed 2 September 2019].
8. Starr MR, Mahr MA, Barkmeier AJ, Iezzi R, Smith WM, Bakri SJ. Outcomes of cataract surgery in patients with exudative age-related macular degeneration and macular fluid. American Journal of Ophthalmology 2018 Aug;192:91-97. [Online]. Available at: https://www.ncbi.nlm.nih.gov/pubmed/29802819 [Accessed 2 September 2019].
9. National Eye Institute. (no date). Age Related Eye Disease Study Results. [Online]. Available at: https://nei.nih.gov/research/clinical-trials/age-related-eye-disease-study-areds [Accessed 2 September 2019].
10. Eye World. (no date). Challenging Cataract Cases and Complications of Cataract Surgery in AMD Patients. [Online]. Available at: https://www.eyeworld.org/complications-cataract-surgery-amd-patients [Accessed 2 September 2019].

Ross Campbell
BSc (Hons) MCOptom Prof Cert Glauc. Prof Cert Med Ret.

Ross is an experienced optometrist, pre-registration optometrist supervisor, and lead assessor for the Wales Optometry Postgraduate Education Centre (WOPEC)… Read more