We are so proud of our team at Sigma Eyehealth Centers!  From our optometric assistants who are a vital part of ensuring you receive nothing but the best eyehealth care to our opticians who truly enjoy helping you select the perfect frame and lenses to our administrative team members who keep the offices running smoothly and do all that they can to assist you with the “paperwork” side of your eyecare, our entire team works to make your visit to our offices a positive experience.  We invite you to learn a little more about each of these outstanding individuals and what they like about working at Sigma!

April Zimmerman

Optometric Assistant

Joined the Sigma Team in July, 2015

“I truly enjoy working with all of the patients in each office and helping them meet their expectations for their eye care needs. It is also a great pleasure to work with such a terrific team at Sigma Eyehealth Centers.”

April enjoys spending time with her kids and going to music concerts when she is not at work. She also attends numerous fire department activities with her husband, Brody, who is a volunteer firefighter on two different fire departments.

Becky Menster

Optometric Assistant

Joined the Sigma Team in August, 2014

“It’s a very rewarding feeling knowing I’ve helped to provide the best possible care for our patients at Sigma, and I feel very lucky to be part of such a great group.”

Becky enjoys spending her time away from the office camping, going on car cruises, cooking, and spoiling her grandkids and great-grandson.

Beth Welsch

Office Administrator

Joined the Sigma Team in February, 1989

“I consider myself very lucky to have joined the Sigma team almost 30 years ago. I enjoy the patients and take pride in knowing we provide them with excellent healthcare and the latest in technology.”

Beth has been a lifelong resident of Monticello. She and her husband, Chuck, raised both of their children, Ben and Kaci, in Monticello. In her free time Beth enjoys playing cards/games with family and friends, working as a licensed wildlife rehabber, and spending time outdoors. More than anything else, though, she loves being “Nana” to her grandson, Declan.

Brenna Hummel

Optometric Assistant

Joined the Sigma Team in November, 2020.

Dacia Finzel

Optometric Assistant

Joined the Sigma Team in August, 2020.

Denise Muller

Optometric Assistant

Joined the Sigma Team in May, 2019

Heidi Driscoll

Optometric Assistant

Joined the Sigma Team in June, 2020.

"Working with the staff at Sigma has been such a learning experience. They have not only shared all of their knowledge, but they are also a fun group to work with! I also enjoy interacting with patients while assisting them with all of their eyehealth needs."

Heidi and her husband are avid Hawkeye football fans. They also love to spend time with their daughter, and in their free time, they enjoy "flipping houses" together.

Roxy Schrader, ABOC, NCLEC


Joined the Sigma Team in August, 2020.

"I love being part of the eyehealth community, and it is clear that Dr. Fisher and his entire team are passionate about what we do here - provide the best eyehealth care using the very latest and greatest technology. I love being part of a team that is all headed in the same direction!"

When Roxy is not working, she enjoys watching and playing games with family and friends, golfing, and traveling. Her greatest joy, though, is spending quality time with her two great kids and stealing long-distance kisses from her grandson!

Sal Ortiz, ABOC


Joined the Sigma Team in March, 2019

Selina Howard-Grant

Office Coordinator

Joined the Sigma Team in August, 2016

“There are several reasons I love working at Sigma -- no two days are the same, we have some of the best patients who I enjoy getting to know and helping out, and the staff are such a fun and knowledgeable group of individuals.”

When Selina is not working, she loves being on the farm, reading, and spending as much time as possible with her husband, family, and friends.

Traci Wulfekuhle


Joined the Sigma Team in November, 2020.

Vicki Hein, CPO


Joined the Sigma Team in September, 1984

“The best part of working at Sigma is working with the patients and helping them meet their eye care needs.”

Outside of Sigma, Vicki enjoys reading, going for walks and spending time with friends.

Kathy Salow

Patient Services Coordinator

Joined the Sigma Team in January, 2015

“What I love about working at Sigma is the versatility the day brings. Each patient that comes in has different needs -- from helping with their insurance to billing questions to scheduling – and it feels good to help them in so many different ways. I also love the people I work with, which makes work fun."

Kathy enjoys spending time with her two sons and six grandkids. She also has two awesome daughters-in-law, and she knows that her sons could not have found better mates. In her free time, Kathy likes to watch the birds at the bird feeders and read.

Debbie Siebels, AAS, CPO


Joined the Sigma Team in November, 1993
Retired from Sigma in May, 2020

“One of the things I enjoy while working at Sigma are my coworkers. They are a pleasure to work with.”

When she is not at work, Deb considers herself a homebody, but she does enjoy spending time with friends and family.