Optical Components Of Myopic Children With Retinopathy Of Prematurity In Preschool Age

Purpose: To examine the optical components and lens parameters change in myopic children with a history of retinopathy of prematurity(ROP)in pre-school age and to identify the relationship between optical components and myopia of ROP(MOR).Methods:The participants were 112 myopic children aged 1 to 6 years which collected from department of ophthalmology in Hunan children's Hospital from January 2014 to December 2015. They were divided into following groups based on gestational age and a history of ROP : Myopia with a history of ROP(MOR group), preterm myopic infants with no history of ROP(MONR group), and full-term myopia(FM group); then collected 30 children with a history of ROP but without myopia in the same period as Non-MOR group,and 37 full-term infants without myopia as the control group. For patients of each group,cycloplegic refraction was examined and recorded as Spherical Equivalent(SE),then optical components including corneal curvature(CR), anterior chamber depth(ACD), lens thickness(LT), vitreous depth(VITR) and axial length(AL) were measured. To compare the optical components difference among groups from different perspectives as age, prematurity, ROP and myopia degree; further comparison about lens thickness variation before and after cycloplegia was made to analyze the lens parameters changing of MOR; finally a paired comparison was made to analyze the dominant factors which influenced their own degree of myopia in MOR.Results:1. The age and gender difference was not statistically significant(P >0.05) among five groups which enrolled in our study;2. Comparison among the five groups: MOR group showed steeper CR?shallower anterior chamber and thicker lens(P <0.01); FM group showed longer VITR and AL(P <0.01);3. Comparison between MOP group(including Myopia with a history of ROP and preterm infants with no history of ROP) and FM group: The SE and CR comparison all showed no significant difference(P >0.05); Compared with the control group, MOP group showed shallower ACD,thicker lens, longer VITR and AL(P <0.05); Compared with FM group, MOP group showed shallower ACD and thicker lens but shorter VITR and AL(P <0.05); 4. 22 patients(61%) in MOR group and 16 patients(47%) in MONR group were infantile myopia; 5. Comparison between MOR group and MONR group: The SE comparison showed no significant difference(P >0.05); Compared with the control group, MOR group showed shallower ACD and thicker lens(P <0.01), while VITR and AL showed no significant difference(P > 0.05), children with MOR aged 1 to 3 years also showed steeper CR; Compared with MONR group, MOR group showed shallower ACD,thicker lens but shorter VITR and AL(P <0.05),while CR showed no significant difference(P > 0.05); 6. Children with severe ROP showed a higher incidence of hyperopia or above than mild ROP(P <0.01), and severe ROP showed shallower ACD and thicker lens(P <0.05); 7.Comparison between MOR group and Non-MOR group: MOR group showed steeper CR and thicker lens(P <0.01) in Children aged 1-3 years; MOR group only showed thicker lens(P <0.05) in Children aged 4-6 years; 8. MOR group showed smaller lens thickness variation before and after cycloplegia compared with Non-MOR group and FM group(P <0.05), which reflected that lens elasticity and accommodation reduced in children with MOR; 9. Paired comparison in MOR group showed severe myopia eyes had thicker lens(P<0.01); paired comparison in FM group showed severe myopia eyes had longer VITR and AL(P <0.01).Conclusions: 1. Children with a history of ROP have a high incidence of infantile myopia. 2. Compared to full-term myopia with increased AL, MOR had characteristic shallower ACD, thicker lens and relatively shorter AL.3. Children with MOR had thick lens and small lens thickness variation before and after cycloplegia, reflecting lens elasticity and accommodation reduced, which may be one of the important factors contributing to MOR.