Abstract:

Objective

The aim of this study is to analyze the relationship between placental growth factor（PLGF）and corneal biological characteristics in pregnant women after laser surgery for myopia.

Methods

A total of 128 pregnant women who were naturally pregnant after laser surgery in the ophthalmology department of Changzhi People′s Hospital from March 2020 to February 2023 and 128 nonpregnantwomen who underwent physical examination in our hospital during the same period were selected as the study objects.The average age was（29.9±3.8）years，ranging from 19 to 42 years.Pregnant women were in the pregnancy group and non-pregnant women were in the control group.All subjects underwent femtosecond laser surgery within 1 year.The PLGF level and corneal biological characteristics of the pregnancy group were detected in the first trimester（T₁），second trimester（T₂），third trimester（T₃）and 6 weeks postpartum（T₄），respectively.The detection time of the control group was determined by the pregnancy group.Serum PLGF，corneal biological characteristics and other quantitative datawere normalized by Shapiro-Wilk test，and the normal distribution was represented by¯x±s.Independent sample t test was used for comparison between groups，repeatedmeasurement variance testwas used for comparison atdifferent time points，and LSD test was used for pair comparison.The measurement data of IOP with skewed distribution were described by［M（P25，P75）］and Mann-Whitney U testwas analyzed.Complicationswere described by cases and percentage and Chi-square test was used for comparison between groups.Pearson correlation analysis was used to analyze the relationship between serum PLGF and corneal biomechanical parameters in different periods of pregnancy.

Results

The serum PlGF，stiffness parameter applanation 1（SPA1），central corneal thickness（CCT），deformation amplitude ratio（DA ratio），corneal resistance factor（CRF），integrated radius（IR）and corneal hysteresis（CH）of women in pregnancy group at each time pointwere（9.42±2.85）pg/m l，（81.25±8.35）mmHg/mm（1 mmHg＝0.133 kPa），（465.25±35.45）μm，5.85±0.82，（6.63±1.26）mmHg，11.32±1.35，（8.13±1.16）mmHg，（61.52±6.83）pg/m l，（73.36±6.62）mmHg/mm，（516.42±38.87）μm，5.32±0.85，（7.38±1.52）mmHg，10.44±1.56，（8.87±1.25）mmHg，（132.37±15.45 pg/m l，（64.54±6.83）mmHg/mm，（546.36±36.63）μm，4.54±0.66，（9.16±1.87）mmHg，8.85±1.42，（9.62±1.38）mmHg，（6.64±1.53 pg/m l，（76.25±8.25）mmHg/mm，（482.65±31.37）μm，5.13±0.68，（7.55±1.65）mmHg，10.56±1.62 and（8.65±1.13）mmHg，respectively..The control group were（5.66±1.42）pg/m l，（86.26±8.52）mmHg/mm，（438.35±28.87）μm，5.92±0.75，（6.68±1.32）mmHg，11.46±1.27，（8.17±1.05）mmHg，（5.18±1.16）pg/ml，（83.37±8.45）mmHg/mm，（442.18±31.36）μm，5.88±0.65，（6.75±1.24）mmHg，11.28±1.22，（8.23±1.12）mmHg，（5.53±1.33）pg/ml，（84.45±6.53）mmHg/mm，（453.56±33.82）μm，5.66±0.83，（6.65±1.18）mmHg，11.37±1.44，（8.26±1.24）mmHg，（5.85±1.45）pg/ml，（82.16±8.18）mmHg/mm，（455.25±35.65）μm，5.63±0.62，（6.82±1.35）mmHg，11.16±1.53 and（8.18±1.17）mmHg.Using two factor repeated measures ANOVA，the group effects of T₁，T₂，T₃ and T₄ in the two groupswere statistically significant（F _group＝5688.222，730.334，135.541，69.729，504.994，159.591，137.416；P＜0.05）.The time effect was statistically significant（F _times＝5851.554129.164，57.561，30.887108.940，63.771，60.579；P＜0.05）.The interaction effect was statistically significant（F _{interactioneffect}＝16153.526，47.442，20.884，34.997，33.607，14.865；P＜0.05）.Pearson correlation analysis showed that therewas no correlation between serum PlGF and corneal biological characteristics at T₁ and T₄，and there was no statistical significance（r＝－0.095，0.114，0.000，0.020，－0.032，0.088，－0.076，0.115，－1.000，0.105，0.044，0.104；P＞0.05）.At T ₂ to T₃，serum PlGF was positively correlated with CCT，CRF and CH，with statistical significance（r＝0.710，0.786，0.212，0.630，0.262，0.455；P＜0.05）；it was negatively correlated with SPA1，Da ratio and IR，with statistical significance（r＝0.544，－0.816，－0.352，－0.612，－0.280，－0.646；P＜0.05）.In the pregnancy group，dry eye and visual acuity regression occurred in 31 cases，with an incidence of 24.22%；16 cases，the incidence was 12.50%.In the control group，15 cases occurred，with an incidence of 11.72%.The incidence was 3.91%.The difference between the groups was statistically significant（χ²＝6.784，6.277；P＜0.05）.

Conclusions

There is a significant correlation between serum PLGF and corneal biological characteristics in pregnantwomen withmyopia after laser surgery in themiddle and late stages of pregnancy.Elevated serum PLGF in themiddle and late stages of pregnancy is accompanied by elevated levels of CCT，CRF，and CH，as well as decreased levels of SPA1，DA ratio，and IR.Moreover，pregnancy after laser surgery formyopiamay increase the risk of dry eye and visual regression.

Key words: Laser surgery formyopia, Pregnancy, Placental growth factor, Corneal biological characteristics