As one of the leading causes of vision loss, uveitis saw Jess develop glaucoma and cataracts on her eyes, resulting in her having to endure five eye surgeries between September last year and January this year, at Wellington Hospital.
"The uveitis is still there, so now it's a matter of waiting to see what happens, but she already has 40 per cent nerve damage in one eye.
"Since glaucoma can make the drains in your eyes become blocked, they put tubes in her eyes to release any fluid build up, which we're hoping will do the job now."
Jess, whose cataracts and glaucoma were a repercussion of using steroid drops prescribed for her uveitis, also had new lenses inserted into both eyes.
Mrs McCullagh says ideally, New Zealand should have access to third generation drugs for arthritis sufferers with uveitis, currently used in Australia.
"The problem we have in New Zealand is those drugs aren't funded or authorised, and it doesn't make sense to me because a child could end up losing their sight over it."
According to Arthritis New Zealand chief executive Sandra Kirby, Arthritis New Zealand currently receives just 12 per cent of its funding from government agencies to support the 578,000 New Zealanders living with arthritis.
For Jess, a Paraparaumu Beach School pupil, and older sister to Holly, 3, her mother describes her arthritis future as "a grey area".
"Originally, when we found out Jess had arthritis, she was put on methotrexate pills, an immune suppressant, but they made her feel too sick.
"Now she is injected with methotrexate once a week instead, which she finds quite hard as it stings afterwards.
"It's a lot for a child to go through."
Mrs McCullagh, who shifted from Ireland to New Zealand with her husband 10 years ago, says she was grateful for opportunities such as the Arthritis New Zealand camp, which invited the children to challenge themselves with new activities including abseiling, flying fox, archery, raft building, kayaking, and a warm water hydroslide.
"Arthritis can be misunderstood, because people don't think children can get it, or that it can go on to affect their eyes.
"It's tough going, but Jess has been so courageous throughout the whole thing."