RESUMO
Objective To evaluate the influence of orthokeratology lenses on vision,intraocular pressure and biometric measurement parameters in adolescent myopia.Methods A total of 72 adolescent myopia patients (136 eyes) with orthokeratology lens,aged 8-16 years old,in Hebei Provincial Eye Hospital from Junuary 2013 to December 2015 were randomly selected.The vision,intraocular pressure,axial length,corneal topography,corneal thickness and anterior chamber depth were observed before wearing glasses,at 1 week,1,3,6 months after wearing glasses.Results After orthokeratology wearing,the uncorrected visual acuity was obviously improved (P＜0.05),the average refraction diopter was declined (P＞0.05) and the non-contact intraocular pressure was decreased (P＜0.05).The axial length after orthokeratology wearing had little change (P＞0.05).The curvature of the patient's cornea at one week after wearing glasses was deceased (P＜0.05) and the posterior corneal curvature tended towards stability.The corneal thickness at 1 week after wearing glasses had no obvious change compared with before wearing glasses(P＞0.05),which at 1 month after wearing glasses was decreased(P＜0.05) and which at 3,6 months after wearing glasses trended to be stabilized.The anterior chamber depth after wearing glasses had no obvious change.Conclusion Orthkeratology lens can decrease the myopia degree,increases the uncorrected visual acuity and has obvious effect for controlling adolescent myopia.The intraocular pressure and biometric measurement parameters have corresponding change after wearing orthkeratology lens.
RESUMO
Objective To evaluate the influence of black dots,isolated line above the best correct visual acuity and multiple lines containing the best correct visual acuity in the accuracy of Jackson cross cylinder examination.Methods Forty students were chosen(11 males,29 females,between 24 to 29 years old).Routine examination of phoropter was used to check under the maximum plus to maximum visual acuity(MPMVA) status.The sequence of three fixation targets was chosen randomly.Astigmatism chart was used to judge the best one when the different results were obtained.Results Among the 80 eyes of 40 students,12 eyes were spherical(the cylinder degree below 0.25 DC).The response of three fixation targets was the same in 19 eyes(27.9%),23 eyes(33.8%)were sensitive to the black dots target,14 eyes(20.6%)were sensitive to the isolated line above the best correct visual acuity,12 eyes(17.6%) were sensitive to multiple lines containing the best correct visual acuity.Kruska Wallis Test was used to detect the difference among three groups.No significant difference was found(?2 =4.026,P=0.134).Conclusion According to the efficiency of examination,communication and judgment,black dots target is recommended although no difference is detected among three fixation targets.