Affecting the central corneal thickness of multi-factor
Author: Wei Bin, with Doherty, Fu Lingling, Wang Xing Jin
【Abstract】 Objective: To investigate the impact of central corneal thickness of the relevant factors. Methods: 306 cases of 612 myopic corneal thickness with ultrasound, computer Refractometer, non-contact tonometer, A Chao, and corneal
topography were measured the data. And analysis of their age, gender, ethnicity, occupation, address, family history of
myopia, history of wearing contact lenses, eye do not, uncorrected visual acuity, corrected visual acuity. Of the results were analyzed statistically. Results: The availability of long-term contact lens wear history of central corneal thickness in myopia that there are significant differences (t = 4.183, P = 0.000). Central corneal thickness and visual acuity, intraocular pressure was positively correlated (r = 0.114, P = 0.005; r = 0.483, P = 0.000); and corneal curvature for the negative correlation (r =- 0.114, P = 0.005). Central
corneal thickness with age-related (r =- 0.041, P = 0.312),
according to age group, comparison between groups statistically significant difference (F = 5.490, P = 0.000), central corneal thickness with age seems to be growth in
thinning trend. Central corneal thickness and myopic refraction was no correlation between (r = 0.027, P = 0.499). The establishment of multiple regression equation: Y = 557.824-7.254X 7 27.989X 9-2.499X 12 5.285X 13 (F = 16.840, P
= 0.000). Conclusion: The impact of central corneal thickness
is a major factor in the history of wearing contact lenses, uncorrected visual acuity, corneal curvature and intraocular pressure.
Key words corneal central thickness factor analysis
In the eye refractive system, the corneal refractive power of about 70% of the total refractive power. Mild corneal refractive power changes, can have significant effects on myopia. However, corneal refractive surgery to achieve the greatest depth of cut the amount of central corneal residual bed thickness of not less than what the value is currently no accurate data and a unified standard. As the central corneal thickness affected by many factors, which affect the current domestic and international scholars, the central corneal thickness of factors, mostly carried out against a sample comparison of a single factor, the lack of multi-factor
comprehensive analysis of joint involvement. The results vary widely, or even completely at odds. This allows the individual
clinical situation of patients with accurate measurement of central corneal thickness has become difficult, which is the choice for the surgical method, surgical planning and operation of the design and operation of the success or
failure has a specific significance. Therefore, we have adopted a multi-factor analysis of epidemiological methods to explore the impact of central corneal thickness of the relevant factors.
An object and method
1.1 Object 2005-11/2006-04 myopia in myopia treatment
centers meet diagnostic criteria for patients, sorted according to patient medical record number, according to random number table, randomly selected subjects (research to meet the sample size is 20 times the number of independent
variables). Reference to the diagnostic criteria of myopia in Australia, "Blue Mountains eye study" the standard :
spherical equivalent ?-1.00D. Exclusion criteria: no corneal organic disease, no history of corneal surgery, eye routine examination no abnormalities, visual field defect-free, no
family history of glaucoma. The study were included 306 cases of 612, 272 men and 136 cases, 170 cases of 340 women; aged 18 to 52 (mean 32.3 ? 5.6) years of age. -1.00 ~ -23.00 Diopters
of myopia (mean -6.60 ? 3.11) D. Grouped according to diopter of myopia: low to moderate myopia group: diopter ?-3.00D, 119
eye; moderate myopia group:-3.00D <diopter <-6.00D, 194 eye;
high myopia group:-6.00D ? diopter "-9.00 D, 200 eye; ultra-
high myopia group: diopter ? - 9.00D, 99 Yan.
1.2 Methods The subjects of the history of the situation, routine inspection items credited to a unified epidemiological questionnaire. Topics covered include: age, gender, nationality, occupation, address, family history of myopia, history of wearing contact lenses, eye do not, uncorrected visual acuity, corrected visual acuity, myopia refraction, corneal curvature, intraocular pressure, axial length, central corneal thickness. Study of factors and their assignment (Table 1). To adopt Japanese Tomey SP-3000 ultrasonic corneal
thickness measurement of central corneal thickness, continuous measurement of all cases three times, whichever is the average. Japan Tomey TMS-4 corneal topography were measured
corneal curvature photo is three higher-quality images, except
for tears and eyelid interference, and then select the best quality of an analysis. Japan Tomey AL-100 A ultrasound
measured axial length, conventional topical anesthesia, continuous measurement three times, whichever is the average.
Japan Topcon8100 Automatic Refractometer measurements diopter of myopia, using the computer after cycloplegic refraction, with the pupil returned to normal emperor felt optometry to determine the diopter of myopia. Japan Topcon CT-60 type non-
contact applanation tonometer intraocular pressure
measurement. Patient was sitting in an appropriate measurement of height and relaxed state, each eye measured three times, whichever is the average. In order to avoid corneal thickness, corneal curvature and intraocular pressure fluctuations at
different times, the results of impact studies [2,3], the Institute and some examinations are 10 am to 12 points. All research subjects measured by double-blind method, one skilled
professionals to operate by the same complete.
Statistical analysis: The SPSS12.0 statistical processing software, will be measured by the number of study factors noted in the number noted in the establishment of library classification. Do affect the central corneal thickness of the relevance of each factor analysis, t test was used to compare between the two groups, multiple groups using analysis of variance and multiple linear stepwise regression analysis, to establish multiple regression equation.
Central corneal thickness and the history of wearing
contact lenses, uncorrected visual acuity, corneal curvature and intraocular pressure related (P <0.01, Table 2,3). Pairwise comparison shows that moderate myopia and high myopia group and central corneal thickness on the group there are
differences (P <0.05), the other was no significant difference among the three groups (P> 0.05). According to Table 1 of the assignment of age (X 1), gender (X 2) ... axial length (X 14) as independent variables, central corneal thickness (Y) as the
dependent variable, multiple linear stepwise regression analysis, the establishment of multi - The regression
equation: Y = 557.824-7.254X 7 27.989X 9-2.499X 12 5.285X 13,
F = 16.840, P = 0.000, results showed that the four independent variables from the above constitutes a regression equation was statistically significant.
With the wide range of corneal refractive surgery carried out, an accurate evaluation of preoperative corneal thickness and corneal shape to a large extent directly related to the
refractive surgical correction of safety and predictability. As myopia in patients with large individual differences in central corneal thickness, which makes clinicians more concerned about how a specific patient's thin flap as much as
possible to preserve the corneal stroma bed is thick enough. This issue in need of laser-cutting deeper high myopia is
especially important. Otherwise, there is cause corneal
expansion and the risk of iatrogenic keratoconus. Therefore, we selected patients with myopia as a research object, and to explore the influence of central corneal thickness of its relevant factors.
With regard to central corneal thickness and myopic eyes do not, gender, address, with or without a family history of
myopia, nationality, occupation, age, myopic refraction, corrected visual acuity and axial length r