【摘要】 目的 探討影響近視患者中央角膜曲率(Kmean)及球鏡屈光度的因素。方法 2008年3月—8月，使用角膜地形圖測量157例(313眼)近視患者Kmean和角膜后表面高度。用A超測量眼軸長度和中央角膜厚度,驗光測出球鏡屈光度。分析可能影響Kmean及球鏡屈光度的多個因素。其中男79例(157眼),女78例(156眼)；年齡18~45歲,中位年齡20歲。近視病程1～30年。近視球鏡屈光度(-5.65±2.74)D。結果 眼軸長度、中央角膜厚度、角膜后表面高度、眼壓、Kmean和球鏡屈光度分別為:(26.00±1.04)mm、(540.50±31.02)μm、(26.96±6.05)μm、(17.05±2.48)mm Hg(1 mm Hg=0.133 kPa)、(43.30±1.46)D、(-5.65±2.27)D。Kmean的影響因素有:眼軸長度(βi=-0.411,P=0.000)、性別(βi=-0.278,P=0.000)、中央角膜厚度(βi=-0.180,P=0.000)[(Kmean(D)=63.9790.599×眼軸長度(mm)-0.813×性別(男=1,女=0)-0.009×中央角膜厚度(μm),R=0.583,F=25.804,P=0.000)]。球鏡屈光度的影響因素有:眼軸長度(βi=-0.911,P=0.000)、Kmean(βi=-0.477,P=0.000)和性別(βi=0.183,P=0.000)[球鏡屈光度(D)=76.585-1.990×眼軸長度(mm)-0.714×Kmean(D)+0.801×性別(男=1,女=0),R=0.837,F=117.295,P=0.000)]。結論 眼軸長度、中央角膜厚度和性別都對Kmean有影響,眼軸增長是近視的主要原因。
Objective To compare the accuracy of different corneal curvature parameters used in toric intraocular lens (Toric IOL) implantation. Methods Patients who underwent phacoemulsification combined with Toric IOL implantation at the Department of Ophthalmology, the People’s Hospital of Leshan between January and June 2022 were retrospectively included. The following data of all patients were collected: age, sex, axial length, anterior chamber depth, total keratometry (TK) and simulated keratometry (Simk, described as Simk1) measured by IOL Master 700 biometric instrument, total corneal refractive power (TCRP) measured by Pentacam AXL panoramic biometric instrument, Simk measured by iTrace visual function analyzer (described as Simk2), astigmatism of the operative eye, and the optometry (including spherical, cylindrical and axial degrees) of operative eyes three months after operation. According to the different corneal curvature parameters (TK, Simk1, TCRP and Simk2) used in the preoperative degree calculation of Toric IOL, patients were divided into four correspondent groups. By analyzing the differences and consistency in postoperative spherical equivalent, variation of postoperative spherical equivalent and postoperative residual astigmatism among the four groups, the accuracy of the four parameters for Toric IOL implantation was evaluated. Results According to the inclusion and exclusion criteria and after propensity score matching, a total of 47 patients (60 operated eyes) were included, with 15 eyes in each group. The spherical equivalent of the TK group, Simk1 group, TCRP group and Simk2 group after operation were (0.38±0.24), (0.49±0.15), (0.69±0.37) and (0.80±0.27) D, respectively. There was no significant difference between the Simk1 group and the TK group (P=0.52), but the differences between the TCRP group, Simk2 group and TK group were all statistically significant (P<0.01). The 95% consistency boundary width of the Simk1 group and the TK group was the narrowest (1.23). The variations of postoperative spherical equivalent of the four groups were (0.25±0.12), (0.39±0.19), (0.64±0.26) and (0.48±0.12) D, respectively. There was no significant difference between the Simk1 group and the TK group (P=0.11), but the differences between the TCRP group, Simk2 group and TK group were all statistically significant (P<0.01). The 95% consistency boundary width of the Simk2 groups and the TK group was the narrowest (0.64). The postoperative residual astigmatism of the four groups were (?0.33±0.12), (?0.57±0.11), (?0.73±0.18) and (?0.70±0.17) D, respectively. The differences between the last three groups and the TK group were statistically significant (P<0.01). The 95% consistency boundary width between the Simk1 group and the TK group was the narrowest (0.58). Conclusion It is a reliable and effective method to use TK to reflect the total corneal curvature and calculate the degree of Toric IOL.
ObjectiveTo investigate the prevalence and risk factors of tessellation fundus (TF) among Tianjin Medical University students with different refractive statuses. MethodsA cross-sectional study. From September to December 2019, 346 students from Tianjin Medical University were randomly selected and underwent slit-lamp examination, non-cycloplegic auto-refraction, subjective refraction, best-corrected visual acuity, ocular biometric measurement, and non-dilation fundus photography. The differences in the prevalence of TF in basic characteristics and ocular biometric parameters were compared. Based on the equivalent spherical (SE), refractive status was divided into the non-myopia group (SE＞－0.50 D) and the myopia group (SE≤－0.50 D). The myopia group was further divided into mild myopia group (－3.00 D＜SE≤－0.50 D), moderate myopia group (－6.00 D＜SE≤－3.00 D), and high myopia group (SE≤－6.00 D). According to the axis length (AL), the subjects were divided into AL＜24 mm group, 24-26 mm group, and ＞26 mm group. The logistic regression was used to analyze the risk factors affecting TF. Trend tests were performed for each risk factor and TF. ResultsOf the 346 subjects, 324 (93.6%, 324/346) were myopia, of whom 73 (21.1%, 73/346), 167 (48.3%, 167/346), and 84 (24.3%, 84/346) were mild myopia, moderate myopia, and high myopia, respectively; 22 (6.4%, 22/346) were non-myopia. There were 294 (85.0%, 294/346) students with TF in the macula, including 9 (40.91%, 9/22), 58 (79.45%, 58/73), 145 (86.83%, 145/167), and 82 (97.62%, 82/84) in non-myopia, low myopia, moderate myopia, and high myopia group, respectively; 52 (15.0%, 52/346) students were without TF in the macula. There were statistically significant gender differences (χ2=4.47), SE (t=6.29), AL (t=－8.29), anterior chamber depth (Z=－2.62), lens thickness (Z=－2.23), and average corneal radius (Z=－3.58) between students with and without TF in the macula (P＜0.05). Spherical equivalent and axial length were independent risk factors for TF and its severity (P≤0.001). With an increasing degree of myopia, and increasing axial length, the risk of TF increased (P for trend＜0.001). ConclusionsThe prevalence of TF is 85.0% among Tianjin Medical University students. TF is detected in the fundus of no myopia, mild myopia, moderate myopia and high myopia. The degree of myopia is higher, the AL is longer, the possibility of TF is higher.