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Trends in magnetic resonance imaging for ophthalmology

Many people visit ophthalmologists and optometrists on a yearly basis. In some cases, this is because of eye problems, such as changing eye sight. In others, this is because they take certain medicines, like some steroids, or have one or more medical conditions, like diabetes, that can lead to issues with the eyes. Ophthalmology, like other fields of medicine, has a variety of disorders and diseases that are possible, which can benefit from the use of imaging tests such as magnetic resonance imaging scans.

What is ophthalmology?

Ophthalmology is the field of medicine that deals with the eyes and all of the different aspects of the eyes.1 There are three main types of eye care professionals that can make up an eye care team: the ophthalmologist, optometrist and optician. Each of these professionals serves their own roles and have differing levels of education and training.

The ophthalmologist is a medical or osteopathic doctor that specializes in the eyes and vision. They complete 12-13 years of training and education and can practice medicine and perform surgery. This training allows ophthalmologists to treat more conditions than an optometrist or optician. They may specialize in different areas, including glaucoma, retina, cornea, neurology, and oculo-plastic surgery. In some cases, ophthalmologists may recognize health problems that aren't directly related to the eye and refer a patient to the appropriate medical doctor.

The optometrist and optician are not medical doctors. Optometrists provide care that includes vision testing and correction and monitoring changes in the eye. They receive a doctor of optometry degree after completing two to four years of college-level education and four years of optometry school. They can also prescribe and dispense corrective lenses or prescribe medications for certain eye diseases. Opticians are trained to design, verify and fit corrective lenses. They use the prescriptions written by the ophthalmologists and optometrists to do this.

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What are some common disorders associated with the eye?2

There are a number of eye problems that patients experience. Some of these last for a short period of time and are minor, but others can lead to permanent loss of vision. The conditions include cataracts, optic nerve disorders, like glaucoma, and macular degeneration.

Cataract appears as a clouding of the eye's lens. It is the leading cause of blindness worldwide. About 20.5 million Americans over the age of 40 have cataract in one or both of their eyes. They can occur at any age as a result of a variety of things, and they may be present at birth. The treatment for cataract is removal.

Glaucoma is a group of diseases that damage the eye's optic nerve, which can cause vision loss and blindness. These diseases occur when the fluid pressure inside the eyes slowly rises. In some cases, glaucoma may occur with normal eye pressure. It can be open angle, which slowly progresses, or closed angle, which occurs suddenly.

Macular degeneration, which is sometimes referred to as age-related macular degeneration, is associated with aging. It affects the macula, the center part of the retina that allows the eyes to see fine details. Macular degeneration can be wet or dry. Roughly 1.8 million Americans aged 40 years and older are affected by macular degeneration.

How does magnetic resonance imaging help?

Magnetic resonance imaging (MRI) can be used in ophthalmology, just like it can be used in many other medical fields. MRI cannot be performed on a patient with metal in the eyes or with certain medical implants. Check with your doctor to see if you are able to have an MRI scan.

MRI can be used to study the soft tissues of the orbit (eye). Ophthalmologists may compare the troublesome side with the normal side to detect abnormalities, though there are certain measurements that they must take.3 MRI of the optic nerve often requires fat-suppression techniques.4 One technique that may be used to image the optic nerve and detect certain diseases is diffusion-weighted imaging (DWI). DWI takes advantage of the random motion of water molecules to note where tissue structures are and detail where the fluid is more restricted.

MRI, including diffusion-weighted imaging, has recently begun to emerge in the field of ophthalmology as an imaging method. The use of DWI can lead to imaging of the optic nerve and its tissue structures. As patients begin to notice vision changes, they should see their eye care team and determine whether they need to see an ophthalmologist. Hopefully, with awareness, we can increase the awareness of eye diseases and their treatment options.

References

1. Jennifer Churchill and Dan T. Gudgel. "What is an Ophthalmologists?" AAO.org. 18 January 2019. Web. 11 June 2019. <https://www.aao.org/eye-health/tips-prevention/what-is-ophthalmologist>.

2. "Common Eye Disorders." CDC.gov. 29 September 2015. Web. 11 June 2019. <https://www.cdc.gov/visionhealth/basics/ced/index.html>.

3. Arathi Simha, Aparna Irodi and Sarada David. "Magnetic resonance imaging for the ophthalmologist: A primer." Indian J Ophthalmol. July-August 2012; 60(4): 301-310. Web. 11 June 2019. doi: 10.4103/0301-4738.98711.

4. Michael J. Hoch, Mary T. Bruno and Timothy M. Shepherd. "Advanced MRI of the Optic Nerve." Journal of Neuro-Ophthalmology. June 2017; 37(2): 187-196. Web. 11 June 2019. doi: 10.1097/WNO.0000000000000511.