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Searching for answers about optic nerve abnormalities

Kristina Teär Fahnehjelm is searching for answers about optic nerve abnormalities, small microphthalmic eyes, and different ocular changes linked to congenital metabolic diseases.
“For me, it’s about determining the best way to look after these young patients and hopefully be able to identify causes so that fewer children are affected in the future,” she says.

Kristina-Tear-Fahnehjelm-foto-Johanna-Hanno
Kristina Teär Fahnehjelm. Photo: Johanna Hanno
Kristina Teär Fahnehjelm is an Associate Professor at Karolinska Institutet and a Senior Consultant at St. Erik Eye Hospital’s paediatric ophthalmology and strabismus clinic. She divides her time between the youngest patients in the healthcare system, being the course leader and Adjunct Professor for the ophthalmology course taken by medical students, and clinical research.

“Working with children adds new dimensions to my job. I get to help a young person with their whole life ahead of them, and I care about that child’s overall situation in life. We really take a multidisciplinary approach and I work in an incredibly stimulating environment!”

International peadiatric network for collaboration

Children from all over Stockholm, and sometimes all over Sweden, are referred to Kristina Teär Fahnehjelm. Many of them have serious and rare conditions. The paediatric ophthalmology and strabismus clinic has access to an international network for exchanging knowledge and collaborating on research.

“When you encounter a rare condition and the patient group is small, I think that it reassures parents and children to know that what we say and do is based on the latest accepted knowledge out there,” she says.

Kristina Teär Fahnehjelm’s fields of research are broad and diverse: monitoring of children with optic nerve abnormalities, microphthalmia and anophthalmia, children with eye problems caused by congenital metabolic diseases, diseases of the liver, and children who have undergone a stem cell transplant – all of which are equally important and interesting.

Her postgrads within the various projects, her supervision of these, and collaborations with paediatricians, psychologists and geneticists are important pieces of the puzzle.

Early choice

Kristina Teär Fahnehjelm was just six years old when she decided that she wanted to be a doctor. The catalyst for this was being forced to spend a prolonged period in hospital after suffering a ruptured appendix. Her mother and father were unable to stay with her.

“There was a nurse who really looked after me. When I had recovered enough, I was allowed to accompany her on her rounds to see other patients. It was a big thing for me. I developed a strong sense that I wanted to be a doctor.”

A good few years later, as an ophthalmologist at Tomtebodaskolan, a specialist school for the blind or visually impaired, she decided to begin researching optic nerve abnormalities. In 2003 she defended her doctoral thesis mainly on optic nerve hypoplasia (ONH), which is the most common cause of blindness in the West.

ONH is a congenital abnormality that results in the optic nerve being thin and underdeveloped. This abnormality is rare and the cause is unclear. It is likely caused by a combination of genetic factors and individual susceptibility in the child.

Piecing things together

“Determining the causes of eye abnormalities is an immense task. You have to piece things together like a jigsaw puzzle, but often the cause remains unclear. Children with ONH are also very different. Some only have slight damage to the optic nerve, while others have serious brain injuries, hormonal deficiencies or neuropsychiatric diagnoses.”

Eye abnormalities can be hereditary with different genetic causes but they can also be due to exposure to the foetus during pregnancy. Some of these so called teratogens are known and some aren’t.

One known cause that Kristina Teär Fahnehjelm has studied more closely is the mother contracting a common virus called cytomegalovirus (CMV) during pregnancy. CMV is the most common congenital infection. Up to 1.5-2 per cent of all children born are infected.

For most, the infection clears up without any problem. Some children, however, develop deafness and approximately one child in five develops ocular changes and problems with their sight.

Children with congenital metabolic disorder

Another project has involved children with leukaemia or other diseases where a stem cell transplant is performed, for example in children with MPS, a congenital metabolic disorder. Children with MPS die before the age of 10 years if they are not given a hematopoietic stem cell transplant.

“We have found that these children are very long-sighted, which is down to the eye being small and the cornea rigid. If we give them glasses early on, their visual development is better. Many of them also develop retinal degeneration with problems to see in the dark. Here too it is important to work together with other adult eye specialists, vision clinics, paediatricians, etc. to get these children the help they need.”

Text: Lisa Thorsén

Name: Kristina Teär Fahnehjelm
Title: Consultant at St. Erik Eye Hospital, Associate Professor and Adjunct Professor at Karolinska Institutet.
Research role: Leads research projects on children with optic nerve abnormalities, microphthalmia or anophthalmia and eye problems among children and adults with metabolic disorders, liver diseases and congenital infections.
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