LASIK surgery is an increasingly popular alternative to wearing glasses or contacts. It reshapes the cornea and changes the focusing power. The intent of the surgery is to correct the curvature of the cornea for conditions that include farsightedness, nearsightedness, and astigmatism (Tortora & Derrickson). Nearsightedness can be corrected by using a concave lens that diverges the light rays coming in so that they are in focus directly on the retina. In farsightedness, the correction is a convex lens that converges the light rays entering to focus directly on the retina (Tortora & Derrickson). After surgery, however, there could be side effects such as dry eyes and sensitivity to light.

There are many different studies being conducted involving the sensitivity of the cornea after the surgery takes place. In one particular scientific study, patients were examined to investigate whether LASIK surgery was the cause of patient’s cornea sensitivity and dry eyes. Twenty patients who had undergone myopic LASIK surgery two to five years previously were placed with ten people who had not received the surgery. The cornea sensitivity was assessed by using a non-contact esthesiometer. (PubMed)

The degree of dry eye symptoms was significantly higher in patients who had received the LASIK eye surgery treatment, rather than the patients in the control group. The majority of patients also reported ongoing symptoms, although the testing for that in particular was not conducted. (PudMed) Some claimed they had never had such symptoms until after the surgery.  It appears that the LASIK surgery could have played a role in the tear deficiency of the patients, as well as the sensitivity.

Works Cited:

Gerard J. Tortora and Bryan Derrickson. Principles of Anatomy and Physiology. 13^th ed., John Wiley and Sons, 2012.

Journal of Refractive Surgery from PudMed.gov 2007. <http://www.ncbi.nlm.nih.gov/pubmed/17455828>

The individual components of the eye work in unison, with each part playing a vital role in providing clear vision.  The cornea acts as the eye’s main focusing segment.  It takes a widely diverging ray of light and bends it through the pupil which is surrounded by the colored iris.  The eye is very complex, and with this complexity various problems can occur.  With new technology, doctors are able to restore many forms of impaired vision.

A new study completed in Kobe, Japan looked into the development of mammalian eyes from stem cells.  Yoshiki Sasai grew what is now known as an optic cup using human stem cells.  This breakthrough was encouraging due to the ability for Sasai to grow three-dimensional tissues unlike the two-deminsional sheets that were being developed.  Observing the optic cup, structural similarities were seen when compared to normal development of an human in vitro eye.  Sasai was impressed to notice that layers of the eye were grown in the same sequence without his aid.

This new achievement could aid scientists in a clinical setting aiding to the increased successes in transplanting stem cell photoreceptors into mice.  This transplant only offered rod receptors that would only give unclear images.  Sasai’s optic cup is being looked at to one day integrate both photoreceptor tissues into humans.

Yoshiki, Sasai, Eiraku Mototsugu, et al. “Self-organizing optic-cup morphogenesis in three-dimensional culture.” Nature. 472.7341 (2010): 51-56. Web. 28 Jan. 2013. <10.1038/nature09941 >.

Tortora, Gerard J., and Bryan Derrickson. Principles of Anatomy and Physiology. Hoboken, NJ: John Wiley & Sons, 2010. Print.

There are many reasons as to why people go blind. For example, blindness can occur because the lens of the eye became cloudy, which prevents light from entering the eye, or because the retina got degraded and deteriorated, which affects the perception of images (1). Another cause of blindness could be caused by a change in eye shape, which alters the projection of an image, or because of damage to the optic nerve, which disrupts the flow of visual information to the brain (1).  Blindness can also occur because of an eye injury or trauma (1). However, the leading cause of blindness in the United States is caused by eye diseases (1).

Because technology has advanced so much in the past few years, people with failing vision can now get a corneal transplant. However, now there is an even better solution to improving eye vision. The University of Tuebingen in Germany has developed a chip that can be implemented into the eye which transforms images into electrical impulses that are sent to the brain, which allows the person to see (2). The clinical trials for the chip implant were done on people who suffered from retinitis pigmentosa, a hereditary condition that destroys the retina (2). The results showed that out of the eleven people who received the surgery, five were able to see or distinguish objects (2).

Although this new chip implant discovery does not work a hundred percent, I believe it is only the beginning. With this new discovery, people who have suffered from blindness can now have the hope that they will be able to see once again. This new discovery will not only provide hope to the family of the victim, but it will also give the victim confidence and raise his or her self- esteem.  He or she will once again be able to live his or her life however he or she wishes. Furthermore, with technology improving every day, I am sure one day people will not have to suffer from blindness anymore.

1.)    Thompson, Dennis. “What Causes Blindness? .” EverydayHealth.com. (2010): n. page.      Web. 30 Jan. 2013.

2.)    Bukowski, Jack . “Let There Be Light: New Technology Enables Some Blind Patients to   See .” InsidersHealth.com. (2011): n. page. Web. 30 Jan. 2013.

Hearing is a process in which the hair cells in the cochlea play a very important role.  Hair cells are stimulated and moved by a vibrating sound wave and they  convert the vibration into an electrical signal that is interpreted by our brain as a sound (Tortora and Derrickson). So as a result of their important role in hearing, when the hair cells are damaged by extended contact with loud noise deafness can occur. A cochlear implant is usually the treatment performed to those with damaged hair cells to recover some hearing (Tortora and Derrickson). However, the Massachusetts Eye and Ear and Harvard Medical School researchers have  successfully performed an experiment in which with the use of a drug managed to regenerate hair cells in deaf mice ( ScienceDaily).

Researchers used a group of deaf mice to test a drug’s effectiveness of turning supporting cells into new hair cells in the cochlea. The drug used inhibited a signal in the Notch protein which surrounds hair cells, and as a result of the inhibition the surrounding cells began to turn into hair cells (ScienceDaily). Afterwards, the deaf mice recovered some hearing because of the regenerated hair cells, and the drug was found to be what caused this improvement in their hearing (ScienceDaily). With the use of an analyses  that showed increase hair cells in the deaf mice ears, researchers further supported the regenerating power of the drug that was used (ScienceDaily).

Researchers are excited to see the results that this drug produced in adult mice because it is the first time hair cell regeneration has been achieved in adult mammals (ScienceDaily).  Implants, surgeries, and other types of treatments for hearing loss can become a thing of the past with this new found research. With further improvements of this drug and more testing, this drug could be used to correct any hearing problems caused by the damage or absence of hair cells. However, for now we should all take the proper precautions to take care of our hair cells by minimizing the exposure to loud sounds for an extended period of time.

Sources:

Massachusetts Eye and Ear Infirmary. “Sensory hair cells regenerated, hearing restored in noise damaged mammal ear. “ScienceDaily, 9 Jan.  2013. Web. 27 Jan. 2013. http://www.sciencedaily.com/releases/2013/01/130109124201.htm

Tortora G.J. and B. Derrickson. 2012. Principles of Anatomy and Physiology. 13th ed., John Wiley and Sons