AP Biology class blog for discussing current research in Biology

Tag: eye

How To Map A Cell

In order to understand diseases on a cellular level, scientists must learn as much as they can about cells. One of the ways this is done, is through Nanomechanics. Through nanomechanics, scientists can measure many aspects of the cell. They can find the thickness, softness, viscoelasticity, and incompressibility, or how capable the cell is of being compressed. Living cells, specifically eukaryotic cells, are made of a plasma membrane with solids inside of it. The solids can range from proteins, to DNA, to organelles, to much more. As these solids move within a liquid type of mixture, they are considered viscoelastic. Through the use of Atomic Force Microscopy or AFM, a cell’s viscoelasticity can be mapped. Moreover, nanomechanics is able to find the rate at which a molecule spins by using Young’s modulus.

201710 SingleCell

Even further in the cell, scientists can now determine how the lipid bilayer of a cell change. Through AFM, the physical properties of the cell’s lipid bilayer have been seen to change due to the concentration of cholesterol. Low cholesterol regions had a more elastic lipid bilayer, while regions with less cholesterol were less elastic. Additionally, it was observed that during ionization, the elasticity of the lipid bilayer decreases as well.

Cell membrane detailed diagram blank

As scientists reveal more about the cell, they connect what they have learned to diseases. When a cell changes, or organelles it is composed of change, it can be a sign of disease. By looking into cells through ways such as optics-based non-invasive Brillouin microscopy, scientists can study the mechanical properties of cells and the smaller components that compose them. From using this type of technology, scientists have also learned that living eukaryotic cells are one of the softest materials on the planet. AFM uses the forces placed on the cell by the microscope to determine the properties of the cell.

Human eye detail, from- Human eye close up (cropped)

One specific use of nanomechanical mapping on cells is in microsurgeries conducted on the eye. Many ocular diseases are due to a change in the mechanical properties of the eye. Some diseases can be caused by macular holes or macular puckers. Through microsurgeries, the damage to the eye may be fixed. Scientists conducted measurements on cells on a nanometer scale in order to understand what microsurgeries are necessary to be performed. Moreover, nanomechanics allows scientists to understand how the proteins of the eyes work, and how mutations and other tissue can affect the eye. If specific mutations of causes of diseases can be found on a cellular or subcellular level, it would aid in the development of drugs that would be used against the diseases.

Put it all in focus

We’ve all had that moment where we squeeze our eyelids into tiny slits in hoping the blurry paper or board in front of us will clear up and wonder, Why am I making my eyes smaller to see better? That doesn’t seem to make sense! The key is to start thinking of your eyes like a camera, a camera with aperture. When we look at something, photons are passing through our corneas and blending light rays together, which then pass through the crystalline lens and vitreous on their way to the retina. The physical building blocks of the eye, rods and cones, turn photons into electromagnetic impulses that are sent to the brain to be interpreted.

So to get to the point, why do we squint? The truth is our lenses try to focus to the best of their ability but they are not entirely flexible. So blurriness is usually indicative of a lens malfunction, missing the target in the back of the retina. When you focus your eyes on something, there are massive amounts of competing light sources and surrounding stimuli in your peripheral vision which can cloud your eyes focus. Heres where the camera reference comes in: squinting your eyes is comparable to tightening the aperture of a camera, allowing less conflicting light to interfere with the image its focusing on. So in fact, squinting your eyes does not work because it is changing the shape of your lenses, but rather because it is allowing less competing stimuli to interfere with its true focus.
If vision is continually blurry, it may not be a simple malfunctioning of your lens but rather due to physical eye damage, in which case glasses might be a good investment. Maybe we should start to think of the aperture of our personal lives a little more as well, theoretically squinting to focus on important tasks and present moments rather than being distracted by the ever-present stimuli around us. Just a thought…
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Big News for Retina Pigmentosa Patients


Photo by luisar

In a recent article, it was revealed that patients with the rare disease retinitis pigmentosa, may be able to find treatment using the Argus II Retinal Prosthesis System. Retinitis Pigmentosa is a rare, only about 100,000 Americans have it, inherited retinal disease that “causes the breakdown of cells in the retina.”

Dr. Robert Greenberg, CEO of Second Sight (the company that created the Argus II Retinal Prosthesis System), stated that those with retinal pigmentosa are “looking down a tunnel that gradually narrows until it disappears entirely.”

The Argus II uses a “video camera and a transmitter mounted on a pair of glasses” to help the individual. “Images are then wirelessly transmitted to electrodes implanted into the patient’s retina.” While the Argus II will not restore vision completely, it will allow users to partially regain vision. Tests show that the Argus II helped patients perform daily activities with ease. These activities included “navigating sidewalks and curbs, matching different color socks, and recognizing large words in sentences.”

Personally, I think this is a great technological leap. This prosthesis system will hopefully reach out to those with retinal pigmentosa and others with macular degeneration.

Your Morning Coffee Can Weaken Your Vision?!

We all love that energizing cup of fresh coffee to start the day, but can too much lead to Glaucoma?

Cup of Coffee

Will you sacrifice your morning cups of coffee to save your eyesight? Photographer: Ian Britton,

The Harvard School of Public Health observed that Scandanavian countries consume the most amount of coffee in the world and also have the highest rates of Exfoliation Glaucoma (EG). Harvard researchers suspected a link between coffee and EG and proceeded to conduct a study. They took 78,900 women and 41,202 men who initially had no signs of glaucoma and had undergone eye exams between 1980 and 2008 and had them answer a questionnaire of how much coffee they drank each day.

The researchers then looked at their medical records to see if there was any evidence of EG present. Those that drank more than 3 cups of coffee a day, compared to those who didn’t drink any coffee at all, showed elementary signs of EG (fibrous material on lens, high pressure on optic nerve, build up of fluid in the eye) and had a 66% increased chance of developing EG. It’s peculiar how the link was only seen with coffee, not other caffeinated products such as soda, chocolate etc.

A question to ask yourself: will this really change the amount of coffee I drink everyday? Given the benefits of coffee: “decreased chance of developing hypertension, diabetes and high cholesterol” does the possibility of developing EG balance out with the health benefits of coffee? I think it’s fair to say that you should and can drink less than three cups a day to stay on the safe side. Besides, isn’t 2 1/2 cups enough to satisfy your craving, support your health and still minimize your chance of developing EG?

For more information you can visit: “Coffee Might Raise Glaucoma Risk: Study” (

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