About Us
Committed to Excellent Patient Care
In the fields of diagnosis, treatment and research, our abiding principle commitment is delivery of the best patient care. We understand the special challenges of living with retinal problems and do everything possible to alleviate these. We collaborate very closely with your primary care provider and your family doctor throughout your treatment. Our staff and physicians are available anytime should a question or concern arise.
We excel in patient care for elementary-aged children to seasoned adults. We serve in a number of locations across the Upstate, and patients are often referred to us from SC, NC, and GA. At Retina Consultants, a doctor remains on call at all times to meet your needs.
Meet Our Doctors
Michael V. Antworth, M.D., M.B.A., Founding Partner
Dr. Michael Antworth graduated from Providence College in Providence, Rhode Island. He received his medical degree from St. Louis University, and after completing his internship, he practiced emergency room medicine. Dr. Antworth went on to practice general ophthalmology at the University of South Florida, where he completed his ophthalmology residency program. He acquired his subspecialty training with a vitreoretinal fellowship program at the University of British Columbia in Vancouver, Canada. After completing his training, he had a successful practice in Tampa, Florida.
In 1990, Michael and his family moved to upstate South Carolina. Four years later he started Retina Consultants of Carolina, P.A. alongside Dr. Trip Renfro. He is currently a participant in ongoing medical and surgical training programs. Dr. Antworth is recognized for contributions to general medical and ophthalmology-specific journals. He serves a two-year rotation as chair of the Ophthalmology Department at Greenville Hospital System and St. Francis Hospital. Recently, Dr. Antworth received his Master’s degree in Business Administration from the University of Massachusetts Amherst.
After several decades of serving the needs of his patients, Dr. Antworth retired from practice in August 2022. He is still active in ensuring that Retina Consultants of Carolina, PA continues its growth and success. Dr. Antworth spends his spare time enjoying photography, biking, and traveling with his wife, four children, and grandchildren.
Office Locations: Greenville Suite B, Clemson, Anderson
Board Certification: American Board of Ophthalmology
Medical School: St. Louis University
Internship: St. Louis University, Department of Medicine
Residency: University of South Florida
Fellowship: University of British Columbia
John F. Renfro III, M.D.
Dr. John Renfro grew up in Spartanburg, South Carolina where he attended Spartanburg High School. He stayed in the Upstate and graduated from Clemson University in 1984 and has remained a member of the alumni association ever since.
Dr. Renfro completed his medical degree from the Medical University of South Carolina in Charleston followed by a one year transitional internship at Greenville Memorial Hospital. He went on to obtain his ophthalmology training at the Eye Foundation Hospital/University of Alabama in Birmingham over the course of a three year residency. In addition, Dr. Renfro furthered his training with a two year vitreoretinal fellowship program with Retina and Vitreous Associates of Alabama.
In 1994, Dr. Renfro joined Retina Consultants of Carolina, P.A., after he and his wife moved to Greenville. His career has included extensive clinical and surgical experience, participation in several national clinical research trials, and medical mission work. Dr. Renfro offers his services at the Greenville Free Medical Clinic and is an active member of the South Carolina Society of Ophthalmology.
John, his wife, and three daughters are all actively involved in various activities in the community and enjoy exploring the outdoors.
Office Locations: Greenville, Spartanburg
Board Certification: American Board of Ophthalmology
Medical School: Medical University of South Carolina
Internship: Greenville Memorial Hospital in Greenville, South Carolina
Residency: Eye Foundation Hospital/University of Alabama in Birmingham
Fellowship: Retina and Vitreous Associates of Alabama
Gregory S. Christensen, M.D.
Dr. Gregory Christensen was born in Minnesota. He completed his B.S. in Medical Technology at Andrews University in 1985 and moved to South Carolina to receive his medical degree from the Medical University of South Carolina.
After a transitional internship at Spartanburg Regional Medical Center, he went to the University of North Carolina at Chapel Hill for a three year ophthalmology residency. In Lexington, Kentucky, he obtained his subspecialty training with a vitreoretinal fellowship at Retina and Vitreous Associates of Kentucky.
Dr. Christensen moved back to South Carolina in 1995 and joined Retina Consultants of Carolina, P.A., in 1997. He has been practicing in Spartanburg/Greenville for twenty years.
Gregory is an avid cyclist. He also enjoys boating, water sports, and traveling with his wife and their two daughters.
Office Locations: Spartanburg, Greenville
Board Certification: American Board of Ophthalmology
Medical School: Medical University of South Carolina
Internship: Spartanburg Regional Medical Center
Residency: University of North Carolina at Chapel Hill
Fellowship: Retina and Vitreous Associates of Kentucky
Gregg M. Kaiser, M.D.
Dr. Gregg Kaiser was born in Pennsylvania but grew up in Memphis, Tennessee. He attended Vanderbilt University in Tennessee and graduated in 1985. In 1989, he completed his medical degree at the University of Tennessee College of Medicine. After obtaining his medical degree, he completed a transitional internship at Baptist Medical Hospital in Memphis. He then went on to complete the Ophthalmology residency program at The Eye Foundation Hospital/University of Alabama, where he was awarded chief resident in 1992. Dr. Kaiser received his ophthalmology training with a two year vitreoretinal fellowship at Retina and Vitreous Associates of Alabama in Birmingham.
Dr. Kaiser began his career at Retina and Vitreous Associates of Alabama until relocating to Greenville, SC in 1997, where he joined Retina Consultants of Carolina. Dr. Kaiser is a member of the Greenville County Medical Society and the South Carolina Medical Association. He is also a long time member of the American Society of Retina Specialists and the American Academy of Ophthalmology. Dr. Kaiser often volunteers his services at the Greenville Free Medical Clinic.
Dr. Kaiser and his wife reside in Greenville with their three daughters and one son. They are active in their church and enjoy traveling and family camping trips.
Office Locations: Anderson, Greenville, Clemson
Board Certification: American Board of Ophthalmology
Medical School: University of Tennessee
Internship: Baptist Memorial Hospital in Memphis, TN
Residency: The Eye Foundation/University of Alabama in Birmingham
Fellowship: Retinal and Vitreous Associates of Alabama in Birmingham
James G. Hall, M.D.
Dr. James Hall was born in Raleigh, North Carolina. After completing his bachelor’s degree at the University of North Carolina in Chapel Hill in 1988, he stayed to pursue his medical degree.
After his internship in the department of Internal medicine at New Hanover Regional Medical Center in Wilmington, North Carolina, Dr. Hall completed a residency program in ophthalmology at the University of North Carolina. He obtained his retina/vitreous subspecialty training with Retina and Vitreous Associates of Kentucky.
Dr. Hall joined Retina Consultants of Carolina in 2000 after practicing in Durham, North Carolina from 1997-2000. He and his wife live in Spartanburg with their daughter and twin sons. Dr. Hall enjoys family time, staying involved in his church, boating, fishing, and golf.
Office Locations: Greenville, Spartanburg
Board Certification: American Board of Ophthalmology
Medical School: University of North Carolina in Chapel Hill
Internship: New Hanover Regional Medical Center, Department of Internal Medicine
Residency: University of North Carolina in Chapel Hill
Fellowship: Retina and Vitreous Associates of Kentucky
Chris Bergstrom, M.D., O.D.
Dr. Chris Bergstrom was born and raised in Kansas. After completing his bachelor’s degree at Southwestern College he received a doctor of optometry degree from the University of Houston College of Optometry. After a short career as an optometrist he returned to school and received his medical degree from the University of Kansas School of Medicine. He did a transitional internship at The Medical Center in Columbus, GA. Dr. Bergstrom completed his residency in ophthalmology at Emory University serving as chief resident his final year. He stayed at Emory for two years of subspecialty training in retina/vitreous and oncology.
After his training, Dr. Bergstrom remained on staff at Emory University taking care of adult patients with retinal diseases and intraocular tumors. He has extensive experience treating and managing patients with intraocular melanoma. During his career at Emory, he was involved in several clinical trials, given numerous lectures, and has several publications in the literature. He is a member of the American Academy of Ophthalmology and International Society of Ocular Oncology.
Dr. Bergstrom and his wife have three daughters. They all enjoy boating, water sports, exercising, and traveling.
Office Locations: Greenville Suite B, Greenwood
Board Certification: American Board of Ophthalmology
Medical School: University of Kansas of Medicine
Internship: The Medical Center in Columbus, GA
Residency: Emory University
Fellowships: Emory University
Daniel Apple, M.D.
Dr. Daniel Apple was born and raised in Southeastern Michigan. He first moved to Upstate South Carolina to attend Bob Jones University where he obtained his bachelor’s degree. After college, Dr. Apple obtained his medical degree from the University of South Carolina in Columbia, SC.
After completing an internal medicine internship at Greenville Memorial Hospital, Dr. Apple completed his ophthalmology training at the University of Minnesota. He then moved back to his home state of Michigan to complete a two year vitreoretinal surgery fellowship at Kresge Eye Institute in Detroit, MI, where he obtained extensive experience in diagnosis and management of complex and advanced vitreoretinal diseases.
Dr. Apple and his wife are excited to return to Upstate South Carolina. They enjoy spending time with their three young, energetic children who keep them quite busy. They also enjoy college football, water sports, and exploring the local culinary scene.
Office Locations: Greenville, Spartanburg, Clemson
Board Certification: American Board of Ophthalmology
Medical School: University of South Carolina School of Medicine, Columbia, South Carolina
Internship: Greenville Memorial Hospital, Greenville, South Carolina
Residency: University of Minnesota, Minneapolis, Minnesota
Fellowship: Wayne State University Kresge Eye Institute, Detroit, Michigan
Joshua Robinson, M.D.
Dr. Joshua Robinson was born and raised in New Jersey, where he graduated Valedictorian from Linden High School. He went on to earn his Bachelor’s degree in Materials Science and Engineering from the Massachusetts Institute of Technology (MIT). After graduation, he worked as an Engineer with Intel Corporation in Hudson, Massachusetts for two years, before deciding to pursue a career in medicine.
Dr. Robinson received his medical degree from Robert Wood Johnson Medical School. He completed his internship and residency in Ophthalmology at the Emory University School of Medicine/Emory Eye Center in Atlanta, and he completed his fellowship in Adult and Pediatric Vitreoretinal Surgery at the world-renowned Associated Retinal Consultants at William Beaumont Hospital in Royal Oak, Michigan.
Following his fellowship, Dr. Robinson returned to Atlanta and served on the faculty at Emory Eye Center for several years. Prior to relocating to the Upstate, Dr. Robinson practiced with Palmetto Retina Center in the Midlands and served on the faculty at the University of South Carolina Department of Ophthalmology.
Board Certification: American Board of Ophthalmology
Medical School: Robert Wood Johnson Medical School
Internship: Emory University
Residency: Emory University
Fellowship: Associated Retinal Consultants[/text_ouput]
Collin Ohning, M.D.
Dr. Collin Ohning was born in Charleston SC and moved to Greenville over two decades ago, where his family has since lived. Dr. Ohning attended Kenyon College where he was a collegiate Academic All-American swimmer. After receiving his bachelor’s degree from Kenyon College, he studied at the Medical University of South Carolina and received his medical degree there.
Dr. Ohning completed his residency and internship at the University of Florida. He then traveled to Washington D.C. to complete his retina fellowship at the prestigious Retina Group of Washington/Georgetown University.
Dr. Ohning is glad to be back in South Carolina serving the Upstate. When not working, Dr. Ohning enjoys golf, basketball, and spending quality time with his fiancé, their two dogs, and family and friends.
Board Certification: American Board of Ophthalmology
Medical School: Medical University of South Carolina
Internship: University of Florida
Residency: University of Florida
Fellowship: Retina Group of Washington