Please answer the following question: Information: - A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The term "laser" originated as an acronym for "light amplification by stimulated emission of radiation". The first laser was built in 1960 by Theodore H. Maiman at Hughes Research Laboratories, based on theoretical work by Charles Hard Townes and Arthur Leonard Schawlow. A laser differs from other sources of light in that it emits light "coherently". Spatial coherence allows a laser to be focused to a tight spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows a laser beam to stay narrow over great distances (collimation), enabling applications such as laser pointers. Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i.e., they can emit a single color of light. Temporal coherence can be used to produce pulses of light as short as a femtosecond. - Visual acuity (VA) commonly refers to the clarity of vision. Visual acuity is dependent on optical and neural factors, i.e., (i) the sharpness of the retinal focus within the eye, (ii) the health and functioning of the retina, and (iii) the sensitivity of the interpretative faculty of the brain. - Mount Royal is a large volcanic-related hill or small mountain in the city of Montreal, immediately west of downtown Montreal, Quebec (in Canada), the city to which it gave its name. - LASIK or Lasik ("laser-assisted in situ keratomileusis"), commonly referred to as laser eye surgery or laser vision correction, is a type of refractive surgery for the correction of myopia, hyperopia, and astigmatism. The LASIK surgery is performed by an ophthalmologist who uses a laser or microkeratome to reshape the eye's cornea in order to improve visual acuity. For most patients, LASIK provides a permanent alternative to eyeglasses or contact lenses. - Canada (French: ) is a country in the northern half of North America. Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean, covering , making it the world's second-largest country by total area and the fourth-largest country by land area. Canada's border with the United States is the world's longest land border. The majority of the country has a cold or severely cold winter climate, but southerly areas are warm in summer. Canada is sparsely populated, the majority of its land territory being dominated by forest and tundra and the Rocky Mountains. About four-fifths of the country's population of 36 million people is urbanized and live near the southern border. Its capital is Ottawa, its largest city is Toronto; other major urban areas include Montreal, Vancouver, Calgary, Edmonton, Quebec City, Winnipeg and Hamilton. - The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. The cornea, with the anterior chamber and lens, refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. While the cornea contributes most of the eye's focusing power, its focus is fixed. The curvature of the lens, on the other hand, can be adjusted to "tune" the focus depending upon the object's distance. Medical terms related to the cornea often start with the prefix ""kerat-"" from the Greek word , "horn". - Chicago (or ), officially the City of Chicago, is the third-most populous city in the United States, and the fifth-most populous city in North America. With over 2.7million residents, it is the most populous city in the state of Illinois and the Midwestern United States, and the county seat of Cook County. The Chicago metropolitan area, often referred to as Chicagoland, has nearly 10million people and is the third-largest in the U.S. - Quebec (pronounced or ) is the second-most populous province of Canada and the only one to have a predominantly French-speaking population, with French as the sole provincial official language. - Mark Cohen is a Canadian laser eye surgeon who practices in Montreal and Toronto . In 2001 , he and Avi Wallerstein founded LASIK MD , Canada 's largest provider of laser refractive surgery . As of 2013 , LASIK MD performs over sixty percent of all laser vision correction procedures in Canada . - Ontario, one of the 13 provinces and territories of Canada, is located in east-central Canada. It is Canada's most populous province by a large margin, accounting for nearly 40 percent of all Canadians, and is the second-largest province in total area. Ontario is fourth-largest in total area when the territories of the Northwest Territories and Nunavut are included. It is home to the nation's capital city, Ottawa, and the nation's most populous city, Toronto. - Keratomileusis is the surgical improvement of the refractive state of the cornea performed by lifting the front surface of the eye by forming a thin hinged flap under which the shape of the cornea is changed by using an excimer laser or other surgical device, and was developed by Jose Ignacio Barraquer, commonly called "the father of modern refractive surgery." A microkeratome is usually used to cut the flap, but a femtosecond laser can also be used to make the flap. Before the advent of the excimer laser, keratomileusis was performed using a cryolathe, which froze thin flaps of corneal tissue and lathe cut them much like one cuts the lens of a pair of glasses. After thawing, these reshaped flaps were placed under the front flap to correct visual improvement. LASIK is currently the only commonly performed keratomileusis procedure. - The Island of Montreal, in southwestern Quebec, Canada, is located at the confluence of the Saint Lawrence and Ottawa rivers. It is separated from Ile Jesus (Laval) by the Riviere des Prairies. - Dr. Avi Wallerstein is a board certified Canadian ophthalmologist and laser eye surgeon who specializes in surgical vision correction, also termed refractive eye surgery. He practises in Montreal and Toronto. In 2001, he co-founded LASIK MD with Dr. Mark Cohen. LASIK MD is Canadas largest provider of laser refractive surgery, performing over 60,000 procedures a year. - The City of New York, often called New York City or simply New York, is the most populous city in the United States. With an estimated 2015 population of 8,550,405 distributed over a land area of just , New York City is also the most densely populated major city in the United States. Located at the southern tip of the state of New York, the city is the center of the New York metropolitan area, one of the most populous urban agglomerations in the world. A global power city, New York City exerts a significant impact upon commerce, finance, media, art, fashion, research, technology, education, and entertainment, its fast pace defining the term "New York minute". Home to the headquarters of the United Nations, New York is an important center for international diplomacy and has been described as the cultural and financial capital of the world. - Toronto is the most populous city in Canada, the provincial capital of Ontario, and the centre of the Greater Toronto Area, the most populous metropolitan area in Canada. Growing in population, the 2011 census recorded a population of 2,615,060. As of 2015, the population is now estimated at 2,826,498, making Toronto the fourth-largest city in North America based on the population within its city limits. Toronto trails only Mexico City, New York City, and Los Angeles by this measure, while it is the fifth-largest (behind also Chicago) if ranked by the size of its metropolitan area . An established global city, Toronto is an international centre of business, finance, arts, and culture, and widely recognized as one of the most multicultural and cosmopolitan cities in the world. - Los Angeles (Spanish for "The Angels"), officially the City of Los Angeles and often known by its initials L.A., is the second-most populous city in the United States (after New York City), the most populous city in California and the county seat of Los Angeles County. Situated in Southern California, Los Angeles is known for its mediterranean climate, ethnic diversity, sprawling metropolis, and as a major center of the American entertainment industry. Los Angeles lies in a large coastal basin surrounded on three sides by mountains reaching up to and over . - In situ (or ; often not italicized in English) is a Latin phrase that translates literally to "on site" or "in position". It means "locally", "on site", "on the premises" or "in place" to describe an event where it takes place, and is used in many different contexts. For example, in fields such as physics, chemistry, or biology, "in situ" may describe the way a measurement is taken, that is, in the same place the phenomenon is occurring without isolating it from other systems or altering the original conditions of the test. - The Greater Toronto Area (GTA) is the most populous metropolitan area in Canada. At the 2011 census, it had a population of 6,054,191, and the census metropolitan area had a population of 5,583,064. The Greater Toronto Area is defined as the central city of Toronto, and the four regional municipalities that surround it: Durham, Halton, Peel, and York. The regional span of the Greater Toronto Area is sometimes combined with the city of Hamilton, Ontario and its surrounding region, to form the Greater Toronto and Hamilton Area. The Greater Toronto Area is the northern part of the Golden Horseshoe. - Montreal officially Montreal in both Canadian English and French, is the most populous municipality in Quebec and the 2nd-most populous in Canada. Originally called "Ville-Marie", or "City of Mary," it is named after Mount Royal, the triple-peaked hill in the heart of the city. The city is on the Island of Montreal, which took its name from the same source as the city, and a few much smaller peripheral islands, the largest of which is Ile Bizard. It has a distinct four-season continental climate with warm to hot summers and cold snowy winters. - LASIK MD is a Canadian provider of laser vision correction and the largest provider of laser vision correction in North America based on procedure volume. As of 2013, LASIK MD performs over sixty percent of all laser vision correction procedures in Canada. LASIK MD was founded in 2001 by Dr. Mark Cohen and Dr. Avi Wallerstein with two initial clinics in Montreal, Canada and Toronto, Canada. As of 2012, there are 30 LASIK MD eye centres located across Canada. The clinics serve all major metropolitan areas throughout Canada. LASIK MD is a provider of laser vision correction, performing LASIK, PRK and keratoconus treatments. The LASIK MD centre in Montreal is the largest private eye care centre in the province of Quebec and also performs cataract surgeries. After reading the paragraphs above, choose the best answer for the entity that related to 'mark cohen ' with the relationship of 'occupation'. Choices: - accounting - canada - cook - diversity - eye surgeon - faculty - fashion - father - major - mountain - ophthalmologist - physics - pupil - research - saint - surgeon
Answer:
ophthalmologist