To measure the choroidal thickness (CT) in the macular area of patients with amblyopia in severe congenital ptosis and to compare the thickness with that of severe congenital ptosis without amblyopia.

A cross-sectional study was performed.Total of 83 eyes of 60 severe congenital ptosis patients were enrolled from January to October in the year 2019 in the Shanxi Eye Hospital, including 29 patients 37 eyes with amblyopia and 36 patients 46 eyes without amblyopia.Thirty-seven eyes of 37 normal people were included in the control group.All subjects underwent mydriatic optometry and the spherical equivalent (SE) was calculated.IOL-Master was used to measure the axial length (AL), and EDI-OCT was used to measure the CT in the macular area.The CT was measured at 13 points: directly beneath the fovea (SFCT) and at 1 mm, 2 mm and 3 mm intervals to the nasal, temporal, superior and inferior to the fovea.The points of CT measurements were named according to their positions and distances relative to the fovea, and represented by SFCT, N1, N2, N3, T1, T2, T3, S1, S2, S3, I1, I2, I3 respectively.The SE, absolute astigmatism degree, AL and CT at each point were compared among the groups.The corrected AL covariance analysis was used to compare the CT at different measurement points among the groups.Spearman rank correlation analysis was used to evaluate the correlation between CT and AL or SE, and unitary linear regression analysis was used to evaluate the influence of age on AL in each group.This study was approved by the Ethics Committee of Shanxi Eye Hospital.All the subjects signed informed consent.

Compared with the non-amblyopia group and control group, the SE and absolute astigmatism value was larger, and the AL was shorter in the amblyopia group (all at P<0.05). The mean SFCT was (388.85±54.85), (301.48±56.68), and (287.08±61.88)μm in the amblyopia group, non-amblyopia group, and control group, respectively.Except for I3, the CT values of the rest parts in the amblyopia group were greater than those in the non-amblyopia group and the control group (all atP<0.05). Except for S3 and I3, the CT values of the rest parts in the amblyopia group were greater than those in the non-amblyopia group and the control group after adjusting the AL (P<0.05). In all the three groups, the CT value was high in the subfovea and was thin in the nasal side.The SFCT was negatively correlated with AL (amblyopia group:r_s=-0.340, P=0.045; non-amblyopia group: r_s=-0.340, P=0.020; control group: r_s=-0.463, P<0.001) and positively correlated with SE (amblyopia group:r_s=0.350, P=0.039; non-amblyopia group: r_s=0.412, P=0.004; control group: r_s=0.450, P=0.005) in each group.Age was the influencing factor of AL in the non-amblyopia group and the control group (β=0.243, 0.225; both at P<0.001).

In comparison with severe congenital ptosis without amblyopia, the SE and absolute astigmatism degree are larger, the AL is shorter, and the CT values at most areas are higher in the severe congenital ptosis with amblyopia.CT value may be associated with the development of amblyopia in severe congenital ptosis.

Congenital ptosis; Amblyopia; Choroidal thickness