Purpose To compare subfoveal choroidal thickness (SFCT) between patients with nanophthalmos and age-matched controls.

Methods This prospective, cross-sectional and comparative study included 31 eyes from 31 patients with nanophthalmos (study group) and 31 eyes from 31 healthy subjects (control group). SFCT and central macular thickness (CMT) were measured with spectral domain optical coherence tomography. All participants underwent a standardised ocular examination including best corrected visual acuity (BCVA), central corneal thickness (CCT), anterior chamber depth (ACD) and refractive error (RE) measurements.

Results Mean SFCT in the nanophthalmic eyes and in the control eyes were 551.3±87 µm and 330.5±46 µm, respectively (p<0.001). Mean BCVA, RE, CMT, axial length (AL), ACD, CCT values were 0.4±0.28 logMAR Unit, +10.6 (3.06), 331.9±78 µm, 18.8±1.5 mm, 2.42±0.4 mm and 577.2±32 µm, respectively, in nanophthalmic eyes and there was a statistically significant difference between groups (p<0.001 for each). There were negative correlations between SFCT with AL (r=−0.836, p<0.001) and ACD (r=−0.597, p<0.001) for the entire study population. SFCT was significantly correlated with CCT (r=0.471, p<0.001) and CMT (r=0.585, p<0.001), RE (r=0.836, p<0.001).

Conclusions SFCT was significantly higher in nanophthalmic eyes. Further studies are needed to evaluate the role of SFCT to explain the pathophysiology of nanophthalmos.