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Meet the Doctors

Dr. Dennis Nietling

Dr. Dennis Nietling is a licensed therapeutic optometrist and glaucoma specialist. Dr. Nietling did his undergraduate work at Michigan State University and Ferris State University. He graduated from the Ferris State University Optometry School. In 1982 he purchased the Denison optometric office from Dr. A. J. Levinson. One piece of advice that Dr. Levinson left with Dr. Nietling before retiring is: “to always strive to learn something new every day”.
Dr. Nietling has continued to gain invaluable knowledge and experience in the management of many ocular diseases, including dry eye, glaucoma, cataracts, macular degeneration, and diabetic retinopathy. He believes that prevention is key and has developed relationships with surgeons and physicians to help co-manage his patients. He, of course, continues to love the “bread and butter” of optometry; that is, comprehensive eye examinations for both glasses and contact lenses to help all ages see better in their daily lives. He works with his patients to find the best options to suit their lifestyle and recreational activities needs, whether it be that perfect pair of glasses or a specialty multifocal contact lens for freedom and flexibility.
His practice philosophy is quite simple- to exceed the expectation of our patients by providing excellent customer service in a timely and convenient manner at a reasonable cost. This service driven approach is fueled by the desire to build lasting relationships with all his patients. His commitment to service with “Big City” knowledge incorporated with “Small Town” heart is what sets us apart from our competitors.
Dr. Nietling and his wife Regina, live in northeastern Grayson County. They have four children, with whom they enjoy spending time. They also enjoy time on Lake Texoma with family and friends. They are members of Waples Memorial United Methodists Church in Denison. The Nietlings are active in the Masonic Lodge, Shriners, and Eastern Star.




Dr. D. Gary Thomas

Proud native Texan, Dr. D. Gary Thomas graduated from the University of Houston College Of Optometry, attaining board certifications in pediatric/developmental optometry and therapeutic glaucoma specialty.
The first half of his career, Dr.Thomas practiced pediatric optometry in North Dallas. He is a Fellow in the College of Optometrists in Vision Development, an international certifying body. He is also a past president of this prestigious organization.
As an Eagle Scout, Dr. Thomas fell in love with Texoma, and this country boy moved his home and offices to Northeast Texas. He became a Diplomate in the American Board of Optometry, specializing in medical disease management.
Dr. Thomas has become a life member of the American and Texas Optometric Association receiving a fifty year award in 2012. Throughout his career, He has been recognized for many achievements including one of the Five Outstanding Young Texans by the Texas Jaycees in 1977.
Dr. Gary Thomas joined Nietling Family Eye Care in 2013. He is a proud supporter of several programs promoting sight for those with financial difficulties and provides eye exams with the Denison Rotary and St. Lukes Mana Ministries.