The Gist of Science Reporter: November 2016

• Study on Cartilage and Bone Formation shows Promising Results (Free Available)
• Seeing the World of Eye (Free Available)
• ISRO Conducts Successful In-flight Test of Scram Jet Engines (Only For The Subscribed Members)

Study on Cartilage and Bone Formation shows Promising Results

For patients of bone-related ailments, good news might be in the offing. Research undertaken by Professor Amitabha Bandyopadhyay at Indian Institute ofTechnology, Kanpur studying the mechanisms of cartilage and bone formation in fetuses and the maintenance of joint cartilage and bone in adults could have ground-breaking applications in the treatment of osteoarthritis and osteoporosis.

In early fetuses the elements of hand and leg skeleton are made of pure unsegmented cartilage. As the fetus grows, this cartilage element is branched and segmented, during which the majority of the. cartilage gets converted to bone. Thus, only afflicted of cartilage remains, capping the Dones at joint sites.

Bandyopadhyay and his team pose that osteoarthritis is nothing but conversion of permanent cartilage to transient cartilage to bone in adults. He is now trying to study whether the gene that promotes formation of bones in fetuses can lead to development of osteoarthritis in adults. If true, he hopes to find means to block this gene which will be a huge leap forward in anti-osteoarthritis drug development research.

His research also shows a way forward in osteoporosis treatments. Osteoporosis is a result of failure to maintain bone mass in adults and post- menopausal women are particularly susceptible to this condition. Until very recently, its treatment was exclusively focused on preventing deterioration of bones post diagnosis but it is only in the last few years that drugs helping in bone regeneration have been used as treatments, though there are adverse effects related to them as well.

Seeing the World of Eye

October 13 is the World Sight Day and the theme this year is ‘Stronger Together’. The theme aptly signifies how different components - researchers in optics, patients, opticians, optometrists, orthoptists, ophthalmologists and allied workers - work together to appreciate, utilize, and advance the world of eye and eye care.

The eye is an interesting organ - a marvel of biological adaptation. Along with the brain it makes a complete processing system consisting of a camera, a filter, an aperture controller and an image sensor. The eye-brain system performs the acts of seeing by first forming the image of the object being seen and then by interpreting this image.

An eye sees just as a camera does a highly sophisticated video camera. The eyelids act as the camera shutter. The compound lens formed by the cornea, a transparent structure in the front portion of the eye, and the crystalline eye lens, form the focusing system of the camera. Iris, the coloured, ring-shaped membrane behind the cornea, acts like a diaphragm. The choroid helps in forming the darkened interior of the camera and the retina acts as a photographic film.

A fluid called the aqueous humour, which fills the space between cornea and iris, helps to maintain the cornea’s optical shape by gentle internal pressure. A fluid called vitreous humour that fills the space between the lens and the retina helps to keep the retina in place.

Limitations of eye also arise due to age or other factors that inhibit its normal functioning. One of the most common limitations is the inability to focus light properly on the retina, known as refractive error or refraction error.
An autorefractometer is a computers machine that facilitates an objective measurement of refractive error and prescription for glasses. The patient is asked to look at the picture inside the machine with one eye and the picture is moved in and out of focus and readings are taken by the machine to determine when the image is on the retina. The machine takes several readings and averages them to form a prescription. This method is particularly useful for examining patients who cannot communicate like young children and those with disabilities.

A Retinoscope provides a more accurate estimation of refractive error than autorefraction. It shines a beam of light into the patient's eye and the reflection (reflex) off the patient's retina is observed. Retinoscopy is particularly useful for . patients who are unable to undergo a subjective refraction test.

Ophthalmoscopy and fundus photography are also used for examination of the fundus - the interior surface of the eye opposite the lens. In fundus photography a photograph of the fundus is captured using a fundus camera that generally consists of a microscope attached to a flash enabled camera.

Examinations through equipments are followed by subjective examinations in which the examiner asks the patient about their vision by using lenses of progressively higher or weaker powers from a trial set. Generally, the term 'visual acuity' (VA), which means acuteness or clearness of vision, is used in this type of examination.

Overcoming Eye Limitations

Eye limitations can be overcome either with the help of glasses or contact lenses or surgical procedures. While myopia can be easily corrected with the use of a concave lens, both hyperopia and presbyopia can be corrected with the help of appropriate convex lenses. Astigmatism can be corrected by refracting light more in one meridian than the other using a cylindrical lens.

A lensmeter is generally used to verify whether the lenses are made as per the prescription of the specialist. It is also used to properly orient and mark uncut lenses, and to confirm the correct mounting of lenses in spectacle frames. Single vision lenses have a single power and can correct for only one distance. A bifocal lens has two optical powers; the upper part of the lens is generally used for distance vision, while the lower one for near vision. Bifocals allow people with presbyopia to see clearly at distance and near without the need to remove the glasses, which would be required with single vision lenses. Progressive or varifocal lenses having variable optical powers provide a smooth transition from distance correction to near correction allowing clear vision at all distances.

Cataract can be corrected by a surgical procedure in which the natural lens is removed and an artificial lens is implanted in its place. If treated early it is possible to slow or stop the progression of glaucoma with medication, laser treatment, or surgery. These treatments work towards decreasing the eye pressure.?

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