Prevalence and inconformity of refractive errors and ocular biometry of 3573 medical university freshman students for 4 consecutive years

INTRODUCTION

CR is the main clinical endophenotype of the refractive status.A more negative or myopic refractive error is associated with a steeper CR. Approximately 35%-95% inter-individual CR variation is associated with genetic factors

. In line with our results, among the adult Egyptian population with myopia,with the increase of myopic diopter, the cornea became steeper

. The LT is changing in one’s life. Children with myopia first showed a pattern of lens thinning, between the age of 10 and 11.5y, the lens reaching thinnest, after 18 years old, it becomes thicken until 75 years old

. The increase in LT could cause myopia drift. For example, in patients with diabetes, glucose may accumulate in the lens, with an increase in curvature and thickness and a shift toward myopia

. Shih

reported that a thinner LT can have an emmetropization effect and may be associated with increased AL, possibly playing a role in myopia progression. However, in 6-18-yearold teenagers, course myopia and lens thickening and thinning association was considered coincidental

. CCT is highly hereditary and is associated with complex eye diseases, such as glaucoma and keratoconus

. Chen

and Sun

reported that CCT was an independent factor, and was not associated with CR, ACD, AL, or refractive error. In our study,the CCT difference was not statistically significant, which was consistent with the results of Chen

’s

study.

Ocular biometric parameters are important for the evaluation of myopia. There is a strong association between ocular biometric parameters and refraction

. Based on refractive status and sex, for the main ocular biometric parameters in young adults,Sun

provided a range of reference values. However,data on ocular biometry remain scarce in medical university students. Axial length (AL) contributes to the variance in spherical equivalent (SE)

. High myopia is usually defined as an AL≥26.0 mm or an SE more than 6.0 D

. High myopia associated with cataracts, myopic glaucoma, or myopic macular degeneration is one of the leading causes of blindness,particularly in European and East Asian countries

.

為確保《意見》有效落實，云南省高院將制定具體方案，將《意見》進一步細化分解，明確任務分工、責任部門和責任人，確保這項工作有人抓、有人管，有人去落實。組織一線法官認真學習領會，切實把文件的精神落實到具體案件的辦理過程始終，讓人民群眾有看得見、摸得著的切身感受，努力做到讓人民群眾在每一個司法案件中感受到公平正義。加強對《意見》實施的督促檢查以及實施效果的跟蹤分析研判，提高對全省法院審判業務指導的針對性和實用性，強化《意見》落實效果。

(2)M=m′∪Part∪Component∪Element，其中：Part表示部件節點的集合，Component表示組件節點的集合，Element表示零件節點的集合。整機由多個部件組成，部件由多個組件和零件組成，組件又由多個零件組成。

SUBJECTS AND METHODS

This study adhered to the tenets of the Declaration of Helsinki and was approved by the Ethics Committee of Tianjin Medical University Eye Hospital(No.2021KY-16). Before the study, all participating students signed an informed consent form.

隨著經濟的發展、城鎮化水平的提高，人們會向大城市聚集，往往伴隨著生育率的下降。比如過去廣東的生育率一直很高，但隨著城鎮化水平的提高，以及珠江三角洲的快速發展，越來越多的人們開始涌向深廣這些發達城市，隨之而來的就是出生率的下降。這是因為大城市房價上漲過快，生活成本更高，會帶來生育的負擔，高房價等經濟壓力正在越來越影響人們的生育決策[4]。所以城鎮化的發展也會在一定程度上影響人口老齡化的進程。

This study was conducted at Tianjin Medical University, China. From 2017 to 2020, 3895 freshman students were invited to participate in this study. Students originated from all provinces of mainland China. Undergraduates who unwilling to cooperate with examination, without successful biometric measurements (

=299), glaucoma (

=2), undergone retinal detachment surgery (

=6) or refractive surgery (

=15)were excluded. Eventually, effective ocular biometric data were obtained for 3573 (91.73%) students in this study.

The examination included distant visual acuity, ocular biometry, and non-cycloplegic refraction.An optical biometer (LENSTAR LS900, i8.2.2.0, Haag-Streit, Koeniz, Switzerland) was used to measure the central corneal thickness (CCT), AL, keratometry power (K),anterior chamber depth (ACD), and lens thickness (LT). Five repeated measurements were taken, and the average value was calculated for each parameter. Non-cycloplegic refraction was measured using an automatic refractometer (model KR 8900;Topcon, Tokyo, Japan) by professional optometrists, and after three measurements, refractive errors [spherical (S), cylinder(C), axis (A)] were recorded.

Refractive errors were classified according to SE. The SE was calculated using the following equation:SE=S+C/2. Emmetropes were defined as SE between -0.5 and +0.5 D. Myopia was defined as an SE＜-0.50 D, whereas hyperopia was defined as an SE＞0.50 D. Myopia was also classified into high, moderate, and mild myopia, based on an SE of ＜-6.00, -3.00 to -6.00, and -0.50 to -3.00 D, respectively.Different criteria were also used to define the extent of astigmatism (cylinder powers 0.50-＜0.75, 0.75-＜1.00, and≥1.00 D). Total astigmatism (TA) refers to the astigmatism of the eye as a complete ocular system. TA was the combined outcome of internal astigmatism (IA) and corneal astigmatism(CA). TA and CA were obtained from the measurement of automatic refractometer and lenstar, using the following formula IA=TA-CA. A cylinder axis of 90°±30° was defined as against-the-rule (ATR) astigmatism, a cylinder axis of 180°±30° was defined as with-the-rule (WTR) astigmatism,and cylinder axis of 31°-59° or 121°-149° was defined as oblique astigmatism. The cylinder power was expressed in the form of a negative. Corneal radius (CR) was extracted from the K value using the formula CR (mm)=1000×0.3375/K (D).The ACD was defined as the distance from the anterior lens to the corneal endothelium. The corrected lens position (LP) was defined as the sum of half of the LT, and the ACD

.

This study investigated the prevalence of refractive errors and determined the distribution of ocular biometric parameters in freshman students at Tianjin Medical University.

3.藥物不良反應觀察：抗病毒藥物的不良反應及耐受性影響患者的服藥依從性，進而影響抗病毒治療的成敗，所以適時監測并及時處理藥物的不良反應對于提高治療效果至關重要（表 7）。……