The Terrassa Childhood Visual Health Cohort (CISViT) research project has revealed novel longitudinal data on the Southern European child population, offering new insights into childhood visual health monitoring. The initiative is led by the Vision, Optometry and Health (VOS) research group from the Universitat Politècnica de Catalunya - BarcelonaTech (UPC), which is linked to the Terrassa School of Optics and Optometry (FOOT). Launched in 2021, the project currently involves over 2,500 participants and provides key epidemiological data on refractive errors and visual development.

Accelerated progression during primary school years
The study focuses on the 8-to-12 age range, a critical period when children experience progressive changes in vision, with a clear tendency toward developing myopia. Accordingly, myopia prevalence increases with age, showing an average annual refractive shift of 0.29 dioptres toward myopia that worsens noticeably over time:

• At ages 8–9, it affects 12.3% of children.
• After one year of follow-up, the figure rises to 17.1%.
• After three years of follow-up, prevalence reaches 28.7%.

Increased risk based on gender and ethnicity
The research also identified significant differences based on gender and ethnic origin. First, results indicate that young girls with myopia constitute a high-risk group due to faster ocular growth progression compared to boys. Second, non-Caucasian children (primarily of Maghrebi or Latin American origin) present a longer baseline axial length at age 8, although their ocular growth pattern remains similar to that of Caucasian children.

Early diagnosis and protective factors
The age of onset of myopia is a critical determinant of long-term prognosis: children who become myopic at a younger age tend to show faster progression and are more likely to develop high myopia in later adolescence.

As researcher Laura Guisasola from the VOS research group explains, “it is possible to anticipate myopia onset before it shows in a child’s prescription, as eye elongation, which can be objectively measured, occurs before myopia becomes detectable in refractive error. Therefore, monitoring axial length growth at these ages makes early intervention possible.”

In this regard, the research identified a combination of low hyperopia at age 8 (below +0.75 dioptres), longer axial length and specific biometric proportions as high-risk indicators for myopia.

It is estimated that by 2050 nearly half the world’s population will be myopic, with almost one billion people affected by high myopia. The study indicates that environmental and behavioural factors influence myopia development. Prolonged screen use is a risk factor, particularly in young children, while family history is widely recognised as a major determinant of childhood myopia risk.

Ultimately, according to researcher Laura Guisasola, “childhood myopia is a progressive, multifactorial process influenced by biological, familial, social and lifestyle factors, with risk increasing alongside a family history of myopia and lower parental socioeconomic status.”

The study indicates that spending more time outdoors and getting more sleep are associated with a lower risk of developing myopia, “tools accessible to families and schools to curb this trend, which can be integrated into public health policies,” states researcher Núria Vila, from the same research group and director of the University Vision Centre (CUV) in Terrassa.

Paediatric screening
The Terrassa Childhood Visual Health Cohort (CISViT) is a longitudinal epidemiological project (2021–2026) collecting temporal data on visual parameters in children aged 8 to 12 across public and charter schools in Terrassa. Study findings are already contributing to the public health debate on paediatric screening and myopia prevention in Catalonia. The research group proposes incorporating paediatric screening to detect risk before the condition develops, recommending preventive ocular growth measurements during routine paediatric check-ups alongside lifestyle assessment.  

The study is conducted at the Terrassa CUV, the FOOT’s visual health clinic offering comprehensive visual care across several specialities. FOOT bachelor’s and master’s degree students complete clinical placements at the CUV through service learning methodology, in which the centre is a pioneer. Annually, around 170 students train across these facilities in Terrassa and Barcelona. 

The CISViT project is part of the Consortium of Refractive Error and Myopia in Children (CREAM-Kids), which harmonises data from visual cohorts worldwide.

Reference paper

• Incidence and Risk Factors of Refractive Error in Children in Spain: CISViT. Project Ophthalmic Physiol Opt.