The normal choroidal thickness in southern Thailand

Area of Science:

• Ophthalmology
• Anatomy
• Biometry

Background:

• Subfoveal choroidal thickness is a key indicator of ocular health.
• Understanding factors influencing choroidal thickness is crucial for diagnosing and managing eye conditions.

Purpose of the Study:

• To investigate the association between subfoveal choroidal thickness and age, axial length, and refractive error in healthy southern Thailand volunteers.

Main Methods:

• A prospective cross-sectional study involving 210 eyes of 105 healthy volunteers in southern Thailand.
• Enhanced depth-imaging optical coherence tomography was used to measure subfoveal choroidal thickness.
• Exclusion criteria included systemic diseases affecting choroidal vasculature; refractive error and axial length were measured using autorefractometry and IOLMaster.

Main Results:

• Mean subfoveal choroidal thickness was 279.4±75.49 μm; mean age was 46.4±16.45 years.
• Subfoveal choroidal thickness showed a negative correlation with age (r²=0.33, P<0.0001) and axial length (r²=0.02, P<0.02).
• Multivariable regression indicated positive correlation with spherical equivalent refractive error and negative correlation with axial length, adjusted for age.

Conclusions:

• Age is the most significant factor influencing subfoveal choroidal thickness compared to axial length and refractive error.
• Subfoveal choroidal thickness decreases by 2.67 μm annually and 14.59 μm per 1 mm increase in axial length.