[Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

OBJECTIVE: To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. METHODS: A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). RESULTS: There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. CONCLUSION: Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

[Orbscan II-assisted intraocular lens power calculation after LASIK].

OBJECTIVE: To evaluate the accuracy of keratometric value derived from one zone of Orbscan II mean power map after Laser in situ keratomileusis (LASIK) in combination with Holladay IOL Consultant software to calculate the intraocular lens (IOL) power. METHODS: A two-part study was conducted at a referral practice. Part 1 was a prospective study of 118 eyes undergoing LASIK. The changes in Orbscan II mean power maps at four central zones (1.5, 2.0, 2.5 and 3.0 mm) were compared with the cornea power calculated from pre-LASIK data to determine the optimum Orbscan II correlation zone. In Part 2, the power of optimum measured by Orbscan II after LASIK was applied to IOL calculations for 62 eyes undergoing LASIK. And the results were compared with the IOL power calculated by the pre-LASIK data. RESULTS: (1) An analysis at the Orbscan II 1.5 mm measurement zone demonstrated an underestimation of net cornea power after LASIK while the 3.0 mm zones demonstrated an overestimation. The 2.0 mm and 2.5 mm zones best approximated the net cornea power calculated from pre-LASIK data; (2) The cornea power at 2.5 mm from Orbscan II was selected for IOL calculations in combination with Holladay IOL Consultant software Holladay II and HofferQ formula. The refractive error calculated by Holladay II and HofferQ formula were (0.47 ± 0.75) D and (0.52 ± 0.83) D versus the IOL power calculated by clinical history method. The refractive errors of two formula within ± 0.50 D were 48.4% and 43.5% and within ± 1.0 D 80.6% and 74.2%. CONCLUSIONS: The cornea power from 2.5 mm Orbscan II zone after LASIK in combination with Holladay II or HofferQ formula can accurately predict the IOL power for cataract surgery.

[Estimation of preoperative corneal power in patients with myopic LASIK based on postoperative corneal data measured from Orbscan II].

OBJECTIVE: Compare the change of pre- and post-operative posterior corneal curvature measurements in peripheral fitting zones using the Orbscan II topographer in patients undergoing myopic laser in situ keratomileusis (LASIK). To establish a new ratio of the anterior and posterior corneal curvature for the calculation of preoperative total corneal power using postoperative corneal data alone in patients after LASIK. METHODS: Retrospectively analyzed the changes of posterior corneal curvature in peripheral 7 to 10 mm fitting zones in 151 right eyes (151 individuals) 3 month after LASIK as measured by Orbscan II. The new ratio between the anterior and posterior corneal curvature was measured. The new ratio was used to estimate pre-operative total corneal refractive power in 30 eyes. The estimated total corneal refractive power was compared with the value measured from Orbscan II preoperatively. The accuracy of intraocular lens power estimated in 2 cases underwent cataract surgery after corneal refractive surgery was studied. RESULTS: The mean difference in estimated pre- and post-operative power of the posterior cornea was (-0.005 ± 0.154) mm (t = 0.417, P = 0.677). The ratio between the preoperative anterior central (0 - 7 mm) corneal curvature and the posterior peripheral (7 to 10 mm) corneal curvature was 1.167 ± 0.030. Estimated mean pre-operative total corneal power was (43.49 ± 1.79) D, whereas the value measuring from Orbscan II preoperatively was (43.77 ± 1.53) D. The mean difference between these two measurements was (-0.28 ± 1.00) D (t = -1.523, P = 0.139). The spherical equivalent refraction after cataract extraction of the two cases undertaken cataract surgery after corneal refractive surgery was 0.54 D and 0.69 D, respectively. CONCLUSIONS: The difference in posterior corneal curvature measurement following myopic LASIK using the peripheral fitting zone with the Orbscan II, as compared to the preoperative values, is clinically insignificant. The pre-LASIK corneal power can be estimated using post-LASIK data together with the new calculated ratio. This will be useful in post-LASIK patients requiring cataract surgery but without the availability of pre-LASIK corneal data for the estimation of the intraocular lens power.

Predicting protein-protein interactions from sequence using correlation coefficient and high-quality interaction dataset.

Identifying protein-protein interactions (PPIs) is critical for understanding the cellular function of the proteins and the machinery of a proteome. Data of PPIs derived from high-throughput technologies are often incomplete and noisy. Therefore, it is important to develop computational methods and high-quality interaction dataset for predicting PPIs. A sequence-based method is proposed by combining correlation coefficient (CC) transformation and support vector machine (SVM). CC transformation not only adequately considers the neighboring effect of protein sequence but describes the level of CC between two protein sequences. A gold standard positives (interacting) dataset MIPS Core and a gold standard negatives (non-interacting) dataset GO-NEG of yeast Saccharomyces cerevisiae were mined to objectively evaluate the above method and attenuate the bias. The SVM model combined with CC transformation yielded the best performance with a high accuracy of 87.94% using gold standard positives and gold standard negatives datasets. The source code of MATLAB and the datasets are available on request under smgsmg@mail.ustc.edu.cn.

TGFB1 as a susceptibility gene for high myopia: a replication study with new findings.

OBJECTIVE: To investigate the genetic association between transforming growth factor beta1 (TGFB1) gene polymorphisms and high myopia in a Chinese population. METHODS: Six hundred adults were recruited for this case-control study, including 300 subjects with high myopia (-8.0 diopters or worse) and 300 control subjects (within +/-1.0 diopters). Seven tag single-nucleotide polymorphisms (SNPs) and 1 coding SNP were genotyped. Their frequencies were compared between cases and controls by statistical tests. RESULTS: Four SNPs in the 5' half of the gene showed significant differences in allele and genotype frequencies between cases and controls. The results remained significant after correction for multiple comparisons. The previously reported association of the coding SNP rs1800470 with high myopia was successfully replicated. The tag SNP rs4803455 in intron 2 was found to account for the positive results of the other 3 SNPs by stepwise logistic regression. The minor allele T of rs4803455 was protective against high myopia with an odds ratio of 0.67 (95% confidence interval, 0.53-0.86; P= .001). CONCLUSION: TGFB1 is a myopia susceptibility gene. CLINICAL RELEVANCE: TGFB1 is the first myopia susceptibility gene successfully replicated. The functional significance of rs4803455 or the genuine causative SNPs in linkage disequilibrium with it remains to be determined.

A protein interaction network analysis for yeast integral membrane protein.

Although the yeast Saccharomyces cerevisiae is the best exemplified single-celled eukaryote, the vast number of protein-protein interactions of integral membrane proteins of Saccharomyces cerevisiae have not been characterized by experiments. Here, based on the kernel method of Greedy Kernel Principal Component analysis plus Linear Discriminant Analysis, we identify 300 protein-protein interactions involving 189 membrane proteins and get the outcome of a highly connected protein-protein interactions network. Furthermore, we study the global topological features of integral membrane proteins network of Saccharomyces cerevisiae. These results give the comprehensive description of protein-protein interactions of integral membrane proteins and reveal global topological and robustness of the interactome network at a system level. This work represents an important step towards a comprehensive understanding of yeast protein interactions.

[Exploration of three-dimensional biometric measurement of emmetropic adult eye-ball by using magnetic resonance imaging technology].

OBJECTIVE: To study biometric measurements of emmetropic adult eyes with magnetic resonance imaging technology (MRI). METHOD: MRI technology, with super-resolution, hyper-speed imaging and the integration of the thin-scanning layer, is applied to measure the three-dimensional biometric parameters of the eyeball. From January to December, 2003, emmetropic eyes from 31 normal Chinese adults (16 males and 15 females) aged from 18 to 32 years old (23.32 +/- 3.32) were successfully measured to obtain the volume of the eyeball and vitreous cavity; inner dimensions of the eye, including the anterior-posterior, vertical and horizontal diameters. The length of ocular axis was measured by A-echo too. Data was analyzed by SPSS 11.0 statistical software. RESULTS: The volume of the eyeball, anterior chamber, lens and the vitreous cavity is (6.013 +/- 0.449) ml, (0.348 +/- 0.020) ml, (0.183 +/- 0.015) ml, and (5.482 +/- 0.440) ml, respectively. The length of anterior-posterior diameter of the vitreous cavity is (16.008 +/- 0.707) mm. The ocular inner dimensions of horizontal, vertical and anterior-posterior planes were (22.455 +/- 0.983) mm, (23.290 +/- 0.815) mm and (22.619 +/- 0.912) mm, respectively. The length of the ocular axis is (23.10 +/- 0.92) mm (with MRI & Orbscan II) and (23.67 +/- 0.82) mm (with A-echo). CONCLUSIONS: The value of the ocular length in emmetropic eye measured with both MRI + Orbscan II and the (A-echo) in the present study is very close to the value of the Bennett-Rabbitts schematic eye (24.09 mm). MRI technology is valuable for obtaining more reliable and precise data in the study of ocular physiology and clinical ophthalmology.

[To pay attention to the research and clinic application of the visual quality].

Superior visual quality not only means normal visual acuity, also includes normal contrast sensitivity, color vision, visual field and binocular vision. The concept of wave-front aberration and its correction technique have been introduced into the ophthalmology in China, and play an important role in finding and resolving the problems related to the visual quality. However, the concept and knowledge of the wave-front aberration does not get popularization in Chinese ophthalmologists. The research and clinical application is scanty. The status should be changed as quickly as possible.

[A study on the mathematical model of normal adult cornea].

OBJECTIVE: To explore the method on the conic equation to establish the mathematical model of the adult cornea and its preliminary result. METHODS: The curvature of anterior cornea and of posterior cornea, the corneal thickness of the points in the distance of 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5 mm away from the apex in the meridians of 0 degrees , 30 degrees , 60 degrees , 90 degrees , 120 degrees , 150 degrees , 180 degrees , 210 degrees , 240 degrees , 270 degrees , 300 degrees , 330 degrees meridians were collected from the Orbscan II topography. Cartesian coordinate was established with the origin at the apex of cornea and its horizontal, vertical and optical axes were defined as axis of X, Y and Z respectively. Then every point was located. The coordinate was circumrotated to establish a new coordinates to relocate the data of the points at the oblique meridians. The mathematical formulas of the meridians sections of the anterior and posterior surface were analyzed as: anterior surface: x2 = a1z2 + a2z, posterior surface: x2 = a1 (z-d0)2 + a2 (z-d0) (d0 is the corneal thickness). And the asphericity Q could be deduced. The mathematical formulas of the anterior and the posterior cornea surface as: anterior surface: x2 a2 + y2 b2 + (z-c)2 c2 = 1, posterior surface: x2 a2 + y2 b2 + (z-c-d0)2 c2 = 1. RESULTS: The mathematical models of the meridian section of the anterior and posterior surface of the cornea show conic formula as ellipse. The mathematical formulas of the anterior and the posterior cornea surface show conic surfaces. CONCLUSIONS: The paper reported a new method in conic formula to establish the mathematical model of the normal cornea. The shape of the meridians sections of the anterior and posterior surface of cornea are ellipse. The shape of the anterior and the posterior corneal surface are both ellipsoid.

[Studies of genetic polymorphism in retinopathy of prematurity].

Retinopathy of prematurity (ROP) is a vasoproliferative disease that happened in preterm infants with low gestational age and birth weight. Recently, many studies suggested that the incidence of ROP and the results of same clinical intervention vary between different races and countries. It seems that ROP may relate with genetic factors. Several genes are suggested to play a possible role in the occurrence of ROP. This paper reviews these related genes.

[The grating acuity of children in preschool age].

OBJECTIVE: To study the developmental trend of the binocular grating acuity of preschool children. METHODS: Binocular grating acuities in 599 children from 2 months to 72 months old (18 groups) were measured using the closed-circuit operant preferential looking system (COPLs). The children included in the investigation were required to be a normal term birth, development and normal eyes, and cycloplegic refraction error within specific limits. The system's reliabilities and measurable rates were also evaluated. RESULTS: The difference of the vision acuities obtained by the same tester on different days has no statistic significance. The measurable rates reached 90% in most age groups. The grating acuity of the children included in the study developed rapidly during first year, and then it reached to a slower development period from 30 to 36-months, the grating acuity stabilized after 3 years old. CONCLUSION: The COPL system is a practical devise to assess the grating visual acuity of infants and preschool children and it can be used to investigate the vision developmental trend including speed, age of its maturation and the top-acuity of the development.

[The volume and dimensions of eyeball analyzed by MRI following encircling scleral buckles].

OBJECTIVE: To assess the changes of the volume and dimensions of the eyeball and the vitreous following encircling scleral buckle. METHODS: 26 eyes from 26 patients received successful broad-band encircling scleral buckles for rhegmatogenous retinal detachment from July 2002 to December 2003. The examinations, A-scan ultrasonography (SONOMED A-5500, USA), Corneal topography and MRI, were performed preoperatively and at the first week postoperatively. The volume of the eyeballs and the dimensions along the three cardinal axes from 13 eyeballs were measured with Gyroscan MR imaging system. RESULTS: The measurement of MRI for the 13 eyes operated with the encircling scleral buckling revealed that the volume of the eyeball was decreased (1.72 +/- 0.49) ml, and volume of vitreous was decreased (1.73 +/- 0.46) ml in the comparison with volume before surgery. Horizontal and vertical dimensions of eyeball were decreased (7.84 +/- 1.86) mm, (7.70 +/- 2.79) mm respectively. The length of circumference was decreased to (24.42 +/- 6.68) mm, the percentage of the decrease was (33.11 +/- 8.69)%. The average high of the buckle indentions was (3.80 +/- 0.58) mm with the average width of (3.82 +/- 0.60) mm in the temperal part and (3.51 +/- 0.76) mm in the nasal part. CONCLUSIONS: The length of the circumference at the site of buckling is shorted, and the volume of the vitreous was decreased after the surgery. The technique of MRI has an important role in the measurement and analysis of the volume and the dimension of the eyeball.

[Design of a quantitative keratoscope used for ocular microsurgery].

A new quantitative keratoscope used specially for ocular microsurgery to measure corneal astigmatism is reported. A combined cylinder-lens, which power can be changed by rotating lens in anti-direction equally, was designed according to the principal of the crossing cylinder lens. The axis direction is fixed when the lens is rotated. The corneal astigmatism can be measured by changing the power of the combined lens to adjust the corneal ring images. The keratoscope could be used to measure the corneal astigmatism quantitatively specially for ocular microsurgery. At the work-distance of 0.025 m, the maximum power of measured astigmatism was up to 8.50 D. The error of the measurement was less than 0.20 D. The keratoscope is a portable lens to be used easily during the ocular microsurgery. The reporting keratoscope is a simple combined cylinder-lens that can be used to measure corneal astigmatism, including the power and the axis of astigmatism, easily during ocular microsurgery.

[A study on the space form of the Schematic cornea of the normal adult eye-ball].

OBJECTIVE: To detect the initial characters of the corneal shape that has been evaluated using a mathematical analysis. METHODS: Subjects were measured with Orbscan II corneal topography system. Anterior and posterior corneal radius of curvature and thickness of the points located 1.5 mm, 2.5 mm, 3.5 mm and 4.5 mm away from the corneal apex on certain meridians, including 0 degrees , 30 degrees , 60 degrees , 90 degrees , 120 degrees , 150 degrees , 180 degrees , 210 degrees , 240 degrees , 270 degrees , 300 degrees and 330 degrees meridians, were measured. The mathematical formula of space-form of the cornea as well as the shape factor (SF) were demonstrated. Distributions of corneal curvature between the two principal meridians were discussed. RESULTS: Mathematical model of anterior and posterior corneal surface were small ha, Cyrillic(2)/8.053(2) + y(2)/7.973(2) + (z-8.226)(2)/8.226(2) = 1, x2/6.836(2) + y2/6.745(2) + (z-8.080)(2)/7.527(2) = 1 respectively. The SF models of the steepest and flattest meridians on anterior corneal surface were e(2) = 1-(15.61z-y2)/z2 and e2 = 1-(15.61 z-x2)/z2 respectively; the same parameters in the posterior corneal surface were e(2) = 1-[12.254 (z-0.553)-y2]/(z-0.553)(2) and e(2) = 1-[12.254 (z-0.553)-x2]/(z-0.553)(2) respectively. The curvature of oblique meridian was described with the formula F' = F(a) + (F(b)-F(a)).Sin(2)alpha. CONCLUSIONS: Anterior and posterior corneal surfaces are both toric similar to ellipsoidal. The distributions of corneal curvature between the two principal meridians have something to do with the law of Sine.