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What are Occluders?

Occluders are devices or structures that block the passage of light or fluid, often used in medical and optical applications. They can range from simple patches to complex valve systems. By controlling flow or visibility, occluders play a crucial role in treatments and experiments. Wondering how these ingenious tools are shaping advancements in health and science? Join us as we explore their impact.
Michael Pollick
Michael Pollick
Michael Pollick
Michael Pollick

During a routine eye exam, the eye doctor often needs to check one eye's acuity compared to the other. In order to do this, the examiner uses a set of special eye covers known as occluders. Some occluders cover the patient's non-tested eye area completely and allow absolutely no light to penetrate. Other occluders have pinholes which allow only a certain amount of light to enter the eye. There are also transparent occluders which create a blurry effect over the non-tested eye. The eye doctor may use different pinhole occluders with different strengths in order to gauge a patient's level of distorted vision, whether it be nearsightedness or farsightedness.

The concept of using a pinhole lens or pinhole glasses in order to strengthen a person's vision naturally has been around for several decades, but there is little scientific evidence to back up such claims. Pinhole occluders limit the amount of available light which reaches the viewer's eye, which can slightly sharpen his or her focus without corrective lenses. The act of squinting also has the same effect, creating a temporary sense of sharp focus until the eyelids relax again. Eye doctors use pinhole or opaque occluders in order to obtain more accurate measurements without the patient voluntarily or involuntarily squinting. The non-tested eye can remain open in its natural position, but the patient cannot use it to read the lines or describe the images.

Eye doctors use differing occluders in order to gauge the extent of a patient's visual distortions.
Eye doctors use differing occluders in order to gauge the extent of a patient's visual distortions.

A typical optical occluder is a handheld device with a small curved cup on the end of a pen-sized stick. Some examiners will use the same occluders for multiple patients, while others will use disposable versions for each patient. The curved cup is designed to fit over the patient's eye socket area but not compress the eyelashes or eyelids. Some examiners allow their patients to hold the occluder in a comfortable position over each eye during the exam. The same light or visual blocking effect can also be achieved while the patient looks through the binocular eye examination instrument. An eye doctor will commonly block each eye in order to determine differences in visual acuity or signs of astigmatism.

Occluders will be used during a routine eye exam.
Occluders will be used during a routine eye exam.

There are also medical devices called occluders which are used primarily by cardiovascular surgeons. These occluders are essentially plugs which are surgically introduced into a leaking blood vessel and directed to the source of the leak. Once in place, the occluder is carefully opened like an umbrella, plugging both sides of the tear securely. This cardiac form of occluder serves a vastly different function than optical occluders.

Michael Pollick
Michael Pollick

A regular TheHealthBoard contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

Learn more...
Michael Pollick
Michael Pollick

A regular TheHealthBoard contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

Learn more...

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    • Eye doctors use differing occluders in order to gauge the extent of a patient's visual distortions.
      By: bellemedia
      Eye doctors use differing occluders in order to gauge the extent of a patient's visual distortions.
    • Occluders will be used during a routine eye exam.
      By: Monkey Business
      Occluders will be used during a routine eye exam.
    • Eyecare professionals use occluders to measure the acuity of the patient's eyes.
      By: Kesu
      Eyecare professionals use occluders to measure the acuity of the patient's eyes.
    • Occluders can be used to gauge a patient's level of distorted vision.
      By: fred goldstein
      Occluders can be used to gauge a patient's level of distorted vision.
    • Patients suffering from visual distortions may be prescribed corrective lenses.
      By: Andres Rodriguez
      Patients suffering from visual distortions may be prescribed corrective lenses.
    • Transparent occluders will create a blurry effect over the non-tested eye.
      By: Jonathan Stutz
      Transparent occluders will create a blurry effect over the non-tested eye.