An optometrist is a doctor who specializes in the field of vision care. These doctors must work very hard and possess great attention to detail as they are dealing with one of the most complex organs of the body, the eye.  The eye is made up of three tunics of tissue starting with the outer layer, the fibrous tunic, which contains the sclera, and the cornea. The outer membrane of the eye is called the conjunctiva. The second layer of tissue is the vascular tissue, which contains the ciliary body. Next in the layer come the lens and the iris. The opening of the eye is a structure called the pupil which regulates the amount of light that gets to the eye. And finally the last tunic is the nervous tunic which contains the retina, which sends images and light to the optic nerve and then to the brain. All these form the basic framework of the eye. 
An optometrist is defined as the main health provider for primary vision care. Their work includes many aspects. For example, among their job requirements, they check the patient for any vision problems such as nearsightedness or farsightedness. They also test for things like the eye's depth and color perception, its coordination and ability to focus, and any diseases. Optometrists reserve the right to prescribe treatments to the patient such as vision therapy and/or rehabilitation.  One type of disease that optometrists usually administer treatment towards is glaucoma. It is a disease that affects the optic nerve, an important part of the eye that gets light from the retina and then transfers the light into image, sending them to the brain. This disease is commonly attributed to causing blindness. It starts by affecting the peripheral vision first, then after some reoccurring injury, moves on to a loss of vision. It is shown by a high amount of pressure in the eye called intraocular pressure. Often the cause that triggers glaucoma is irregular blood flow to the optic nerve. 
Optometrists also give standard eye examinations to check up on any new developments that may have affected the patient’s vision. They also test for nearsightedness and farsightedness. The main point of the exam though, is to make sure that there are no problems with the patient’s vision. Eye damage or injury is hard to detect without special treatment. Unless obvious harm is done, the patient doesn’t even realize the danger they are in. So a comprehensive eye examination is always good to get on a regular basis. The certain type of test that the patient has will of course depend upon the patient’s medical history, any signs or indications of difficulty, and the doctor’s level of experience. 
First the patient must go through the preliminary process of checking up on their medical history. The doctor will ask routine questions about general health, medication and/or treatment to take, and any problems or trouble the patient has been having. It’s necessary to ask these questions in case any abnormalities show up. The doctor might also assign to put the patient through a series of tests to measure depth perception, eye prescription, color vision, peripheral vision, muscle movements, and how the pupils are stimulated by the amount of light. Optometrists also use eye charts to evaluate farsightedness and nearsightedness. They have the patient stand a fixed distance away from the reading chart, composed of letters varying in size- bigger letters on top and smaller letters towards the bottom. The patient must read out letters off the chart covering one eye and then the other. This is called visual acuity testing. A patient’s end results are written in fraction form. Normal visual acuity sight is written 20/20. The number on top is the distance from where the patient read the letters out. The number on the bottom is the size of the smallest letter the patient was able to read.
Keratometry is a test that examines the curvature of the cornea, which is the outer covering of the eye. Optometrists use a light to shine into the patient’s eye and measure the reflection that shows up. It is used primarily in finding a right fit for contact lenses. An important procedure done for eye prescriptions is refraction. Optometrists use refraction to discover any refractive errors, the errors found when using a light to focus the eye, which the patient may have. These may include astigmatism. A medical tool called the phoropter is utilized as well as a retinoscope to examine how well the patient’s eyes focus on light with a variety of different types of lenses. Depending on how the patient responds, the doctor can draw up results of which of the lenses provide the best visual quality. It is with this that the optometrist can prescribe the patient with the prescription that suits them best. Eye drops may or may not be used during this procedure. Other exams that can be taken to further evaluate the condition of the eyes are eye movement testing, eye health evaluation, and supplemental testing. 
Optometrists use specially made instruments to carry out their work. This branch of medicine requires a lot of precision and detail. They aren't allowed to do anything half-heartedly, for risk of putting the patient in a dangerous position. This is why they rely heavily on their tools to help guide them. One piece of equipment that optometrists use is a slit lamp which lets the doctor see the details of the front of a patient's eye during an appointment. Also commonly used is a device called the phoropter. A phoropter looks sort of like a huge pair of glasses, with multiple lenses, that determines the correct prescription of both the patient's eyes. 
To become a certified Optometrist, all levels of education and schooling must be completed. In the U.S., a student in high school who already wants a career in medicine should take four years of science classes including biology, physics, anatomy and physiology, and chemistry. After high school it essentially does not matter which college or university the student attends, as long as it is accredited and maintains exceptional science courses. It is also advisable to take a pre-med course to prepare for the future. The field of optometry is extremely competitive. In 2007, the amount of students who applied and entered into a good optometry school was measured by a ratio of 1 to 3. Also required is the Optometry Admissions Test (OAT), which includes a survey of natural sciences, a reading comprehension section, a test over physics, and a quantitative reasoning section. It is suggested that a student take this exam more than once to have an opportunity to raise their scores if they wish. Colleges and medical schools want a well-rounded student. They are not only looking for good grades, but an extensive background in medicine, too. 
The specific classes that are required to apply are English, mathematics, physics, chemistry, and biology. Once accepted into a four-year optometry college, it becomes slightly less complicated. There are recommended classes such as health and visual sciences and clinical training in the diagnosis and treatment of eye diseases. Other classes that are offered are pharmacology, optics, vision science, biochemistry, and systemic diseases. After graduating, there are residency programs that allow a year of residency to an optometrist with a desire to specialize in a certain branch of optometry that includes general family practice optometry, pediatric optometry, geriatric optometry, vision therapy and rehabilitation, cornea and contact lenses, refractive and ocular surgery, primary eye care optometry, and ocular disease. 
The field of optometry is very frugal. The salary that an optometrist makes is determined by the level of experience that he or she have. This is a leading factor in many areas of medicine because the more experience and skill that a doctor holds is essential to doing a good job. Hospitals and clinics look for seasoned physicians more so than younger ones because they already know the procedures. There is no need to review the rules and regulations or training. This is why doctors get paid pretty generously and why the salary range for optometry is relatively big. The other factors that account for this are a doctor’s working hours and the location of the practice. The average salary for a working optometrist would be approximately $90,000. Ten percent of the whole earn more than $150,000 per year. Around fifty percent earn from $60,000 to $100,000 per year. In contrast to an optometrist involved in their own private practice, doctors working with a hospital or clinic make more in the beginning years by way of salary. But private practitioners earn more money in the future because of their skills in a specific area of optometry. Aside from their pay, optometrists gain other perks such as social security benefits, disability benefits, and pensions. They are also given valuable vacation time. 
- Optometrists Bureau of Labor Statistics. U.S. Department of Labor. Occupational Outlook Handbook, 2010-11 Edition. December 17, 2009.
- Wile, Dr. Jay L. and Marilyn M. Shannon, M.A. The Human Body: Fearfully and Wonderfully Made!. Published by Apologia Educational Ministries, Inc. 2001.
- Glaucoma Lawrence J. Schwartz, MD. Medicine Net. April 23, 2007.
- Comprehensive Eye and Vision Examination American Optometric Association. 2006-10.
- What are the Optometry Tools? TV Lesson.
- Optometrist Salary Range Charlie S. Buzzle.com. 2000-2010.
- Summary Report for Optometrists O*NET OnLine.