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PubMedDate not supplied

First trimester diagnosis of split hand/foot by transvaginal ultrasound.

OBJECTIVE/METHOD: First trimester high-frequency transvaginal ultrasonographic examination was performed in a 26-year-old gravida 2, para 1, diagnosed with tetramelic split hands and feet. The couple was informed about the probable 50% recurrence risk of this anomaly. RESULTS: At 12 weeks' gestation, high-frequency transvaginal ultrasound examination revealed a fetus with biometry consistent with gestational age. Both hands appeared to have a single digit at the ulnar side. On the site of the metacarpal bones, only three bones could be visualized. Both feet showed two digits, with a typical 'split-foot' appearance. Nuchal translucency thickness measured 1.0 mm. No additional abnormalities could be found. The child was born in good condition with the described split hand/foot malformation (SHFM). CONCLUSION: This case report demonstrates prenatal sonographic diagnosis of SHFM in a first trimester fetus. In first trimester there can be several technical advantages and it shortens the period of uncertainty of the parents. Secondly it provides the option of early surgical termination of the pregnancy instead of induction of labour.

Adult↗

PubMedDate not supplied

Sonographic cervical volumetry in higher order multiple gestation.

OBJECTIVE: The aim of this study of multifetal pregnancies was the comparison of three-dimensional (3D) volumetry of the cervix, conventional sonographic cervical length measurement and clinical assessment. METHODS: 10 mothers were investigated in an observational study between 5/1999 and 9/2000. A total of 34 consecutive 2D- and 3D-transabdominal ultrasound measurements were performed. RESULTS: Volumetry of the cervix was possible in all 34 exams. 2D-cervical length assessment could not be obtained in 6% because the presenting fetal part obstructed the sonographic plane. Both methods allowed equal judgement of the configuration of the cervix. A significant correlation was found between mean 2D-cervical length (28.7 mm, 7.7 SD) and mean cervical volume (30.0 cm3, 16.0 SD). Parity, subjective preterm labor or need of tocolytics showed no correlation with any biometrical parameter studied. CONCLUSION: Volumetry was superior for the assessment of cervical biometry and conformation in women when the transabdominal 2D-plane was obstructed. When cervical length was obtainable by a conventional scan, the technically more complex 3D-imaging did not provide further information.

Adult↗

PubMedDate not supplied

Predicting postoperative anterior chamber depth in cataract patients using Scheimpflug slit photography.

PURPOSE: To predict the postoperative anterior chamber (AC) depth from the preoperative in situ position of the lens central clear zone (CCZ) using Scheimpflug slit photography. METHODS: 111 eyes of 78 cases that underwent phacoemulsification and intraocular lens (IOL) implantation were examined. 748 eyes of 383 healthy subjects with transparent lenses were used as the control. Scheimpflug slit photography was done under maximal mydriasis, and biometry was performed on the photographs. Two types of acrylic IOLs (MA30BA and MA60BM, both from Alcon) were used in this study. The preoperative AC depth (L1), the distance between the anterior lens capsule and lens CCZ (L2) and the postoperative AC depth (I1) were determined. I2, the predicted postoperative AC depth, was then determined from a linear regression of L1 + L2 and I1. RESULTS: L2 thickened by 0.014 mm/year, and L1 decreased by 0.016 mm/year in the transparent lenses. L1 + L2 changed little with aging in both cataractous and transparent lenses. L1 + L2 and I1 showed a linear correlation with r = 0.80 in the MA30BA and r = 0.77 in the MA60BM groups. The mean error values between I1 and I2 were 0.095 +/- 0.096 and 0.123 +/- 0.114 mm in MA30BA and MA60BM, respectively. The error between I1 and I2 was within +/- 0.17 and +/- 0.33 mm or less in 72.9 and 91.5% of MA30BA and in 82.7 and 96.2% of MA60BM. In contrast, the error between I2 and I1 when calculated using the SRK/T formula was much larger - in excess of +/- 0.33 mm in 38.7% of the eyes. CONCLUSIONS: L1 + L2 changes little with aging and is considered a useful marker of the position of the crystalline lens in situ. There was a high correlation between I1 and L1 + L2. These allow a far more accurate prediction of I1 than previous methods. In combination with the conventional regression formula and ray tracing, a highly accurate IOL power calculation can be attained.

Aged↗

PubMedDate not supplied

Cephalic index is not a useful sonographic marker for trisomy 21 and trisomy 18.

OBJECTIVES: To evaluate whether the cephalic index (CI) in trisomy 21 (T21) and trisomy 18 (T18) fetuses is different from that in euploid fetuses, and if so, is this difference of clinical utility. METHODS: Retrospective. Over an 18-month period, patients attending a single centre for routine advanced maternal age amniocentesis were recruited for a prospective study of ultrasound soft markers of aneuploidy. This prospective database was searched for cases with the following criteria: (1) occipitofrontal diameters (OFD) measured at least twice; (2) gestational age between 98 and 126 days either by ultrasound-confirmed menstrual dates or early second- trimester biometry; (3) no major central nervous system abnormalities detected on prenatal ultrasound, and (4) normal fetal karyotype. This constituted the control group. The study group consisted of all cases of prenatally diagnosed T18 and T21 identified in the same time period with criterion 2 as above. The fetuses in the study group had the OFD measured in a blinded fashion from the biparietal diameter images. CI (= mean biparietal diameter/mean OFD) was calculated for all fetuses. Pearson coefficient and regression analysis were used to determine independence of CI to gestational age in the control group. Standard descriptive statistics were used to describe interval data and two-tailed t test was used to compare means between the study and control groups. ROC curves were constructed to evaluate the clinical efficacy of CI for T18 and T21. RESULTS: Five hundred and ninety-seven fetuses were available for analysis. There were 551 fetuses in the control group and 46 in the study group. Within the study group, there were 30 T21 and 16 T18 fetuses. Within the control group, CI was independent of gestational age (R = 0.026, p = 0.922). Mean CI for the control group was 0.802 (SD 0.040) and this was not statistical different from either the T21 group (mean 0.816, SD 0.042, p = 0.067) or the T18 group (mean 0.792, SD 0.057, p = 0.491). Area under the ROC curves was determined for both T18 and T21 and both had poor results (0.545 and 0.598, respectively). When CI was evaluated in the control group according to the two main ethnic groups in the study, there was a trend towards a statistical difference (p = 0.046) between the fetuses of Oriental and Caucasian mothers. CONCLUSIONS: In this retrospective study, CI was not found to be statistically different between the study and control groups. Although a trend towards significance was seen with T21, this difference is not clinically useful. There may be interethnic differences in the CI between fetuses. CI is not useful for aneuploidy screening by ultrasound.

Biomarkers↗

PubMed2006

Ultrasound assessment prior to laser photocoagulation for twin-twin transfusion syndrome for predicting intrauterine fetal demise after surgery in Japanese patients.

OBJECTIVE: To evaluate the use of ultrasound before selective laser photocoagulation of communicating vessels (SLPCV) for twin-twin transfusion syndrome in predicting intrauterine fetal demise (IUFD). METHODS: Fifty-five patients underwent SLPCV in Japan. Fetal biometry and Doppler studies of the umbilical artery, ductus venosus, and umbilical vein were performed prior to SLPCV. The visualization of the bladder and hydrops was recorded. Association between the parameters and IUFD was analyzed using multiple logistic regression analysis. The study was approved by the Institutional Review Board and patients gave their informed consent. RESULTS: The IUFD incidence was 25.5% (14/55) in the donors and 12.7% (7/55) in the recipients. Twelve donors and 4 recipients of them ended in unexplainable IUFD. In the analysis of 53 donors, absent or reversed end-diastolic flow of umbilical artery (UAAREDF) was only associated with IUFD (p = 0.016). No parameters could predict IUFD in 52 recipients. CONCLUSIONS: UAAREDF may be useful for predicting IUFD of the donor after SLPCV.

Asian People↗

PubMed1994

Serum erythropoietin in small for gestational age fetuses.

Serum erythropoietin (Epo) concentration was compared prenatally in adequate (AGA) and small for gestational age (SGA) fetuses. Fifty-four percutaneous umbilical blood samplings were paired with maternal blood and assessed for Epo, hematocrit and reticulocyte count. Seventeen fetuses were growth-retarded (SGA) on the basis of ultrasonic biometry and birth weight. Controls (AGA; n = 37) underwent cordocentesis for risk of toxoplasmosis, maternal age or malformations (CNS, GI, heart). No cytogenetic abnormality or infections was found in the 54 fetuses. Linear and polynomial regressions were fitted to determine correlations between parameters. Nonparametric Mann-Whitney test was used for comparison between groups. Gestational age at sampling was similar in AGA and SGA. The SGA fetuses had a higher Epo concentration than controls (p < 0.001). Fetal AGA Epo increased significantly throughout pregnancy (p < 0.01) but did not correlate with maternal Epo (p > 0.05). An inverse correlation was found between fetal reticulocyte count and Epo concentration (p < 0.02). The mechanism of high Epo level in SGA fetuses may involve low pO2 and hemoconcentration.

Erythropoietin↗

PubMed1990

Quantitative chamber angle measurement utilizing image-processing techniques.

An image-processing technique was applied to the measurement of the anterior chamber angle. The anterior eye segment was documented by a new instrument, named anterior eye segment analysis system for biometry of the anterior eye segment. The approximated curve of the corneal posterior curvature and the line tangent to the anterior surface of the iris were calculated as the anterior chamber angle. The mean error of the reproducibility of repeated measurements for the same image was 1.6 +/- 0.81% and that of 3 images of the same eye which were taken at 3 different times was within 5.2%.

Adult↗

PubMed1995

Evaluation of lens transparency changes through photographed images during a 13-month observation period.

Since the development of the anterior eye segment analysis system, several new types of anterior eye segment biometry have been performed. The main aim of this study was to evaluate whether changes in cataractous progression or an increase in lens transparency loss are detectable during a relatively short period of 13 months by measuring the intrapupillary opaque shadow area through retroillumination images or by calculating the light scattering intensity at the deepest cortical layer of the lens through Scheimpflug slit images. Secondly, the relationship between maximally dilated pupil sizes and patients' ages and that between cases with and without diabetes were studied. Thirty-one eyes (49.2%) of sixty-three cataractous lenses showed more than 5% increase in the opaque shadow area. Forty-five eyes (60.0%) showed more than a 5% increase in light scattering intensity. 92.5% of diabetic eyes and 92.3% of nondiabetic eyes showed pupil sizes over 6.5 mm after an instillation of mydriatica. In our study the applied method guaranteed a high reproducibility; thus is might be possible to detect an increase in cataractous changes and lens transparancy in around 50% of examined subjects in a period as short a 1 year. For the evaluation of cataract progression through a retroillumination image, the recommendable pupil size is > or = 6.5 mm.

Aged↗

PubMed1996

[Value of ultrasound in early detection of endometrial carcinoma].

OBJECTIVE: The purpose of our study was to examine the diagnostic value of the biometry of the endometrium for the early detection of endometrial carcinomas in postmenopausal women as well as to compare our results with those of other authors. METHODS: In 69 post menopausal women the endometrial thickness measured by vaginosonography before diagnostic curettage or hysterectomy was compared with the histological results. RESULTS: Using a cutoff value of 6 mm, a sensitivity of 96%, a specificity of 24%, a positive predictive value of 16%, and a negative predictive value of 97% were established. CONCLUSIONS: Endovaginal ultrasound evaluation of the endometrial thickness is not specific enough to be used screening method for the early detection of endometrial carcinoma.

Aged↗

PubMed1990

Physical and technical foundations of diagnostic ultrasound.

The physical and technical foundations of investigations with diagnostic ultrasound are discussed. Two questions need to be answered: what is ultrasound, and how does an ultrasonic device operate? The mechanical properties of the human body are described by physical laws, such as the propagation of ultrasound waves, the interaction of ultrasound with tissue, attenuation, reflection, refraction, etc. Today high-technology ultrasonic devices are driven by computers. Imaging of the same kidney with different devices shows the progress made in image quality over a period of about 15 years. Details of tissue and biometry are largely enhanced. Powerful tools allow different forms of precise analysis of online measurements. Advanced handling of information gives further opportunities to image processing. The final question is the extent to which the physician and surgeon want to work with such as sophisticated high-technology imaging system and learn to manage its hard- and software.

Humans↗

PubMed1975

The emmetropic and the iseikonic implant lens: computer calculation of the refractive power and its accuracy.

The preoperative calculation of the power of a lens prosthesis and the resulting aniseikonia is given, as well as diagrams for reading the emmetropizing and the iseikonizing power of the lens. The consequences of an inaccuracy in the measurement of the dimensional and refractive properties of the eyes are calculated. It can be concluded that the main determinant for an accurate prediction of the power of the intraocular lens prosthesis is the axial length measurement. Since this measurement is carried out by means of ultrasound biometry, it is necessary to emphasize the adequate application of this technique. The problem as to whether an emmetropizing, or an iseikonizing lens should be implanted may be solved with the data supplied by the computer program. A flow chart for this program is given in an appendix.

Anterior Chamber↗

PubMed1989

Determinants of early recurrence of cerebral infarction. The Stroke Data Bank.

We studied 1,273 patients with ischemic cerebral infarction who were entered into the Stroke Data Bank, a prospective, observational study involving four university hospitals and the Biometry and Field Studies Branch of the National Institute of Neurological Disorders and Stroke. Forty patients had noniatrogenic recurrent stroke within 30 days after the index cerebral infarction. Using life tables, the 30-day cumulative +/- SE risk of early recurrence for all infarctions was 3.3 +/- 0.4%. The risk of early recurrence was greatest for atherothrombotic infarction (7.9 +/- 2.2%, eight of 113 patients) and least for lacunar infarction (2.2 +/- 1.2%, eight of 337 patients). Both cardioembolic infarction (4.3 +/- 0.9%, 10 of 246 patients) and infarction of undetermined cause (3.0 +/- 0.5%, 14 of 508 patients) had intermediate risks. History of hypertension and diabetes mellitus, as well as diastolic hypertension and elevated blood sugar concentration at admission, were associated with early recurrence. Logistic regression analysis estimated the risk of early recurrence to be 8.56% in those with coexisting hypertension and a glucose concentration of 300 mg/dl versus 0.77% in the absence of these two abnormalities. Early recurrence was associated with longer median duration of initial hospital stay (27 vs. 14 days) and a higher 30-day case-fatality rate (20% vs. 7.4%). Increased weakness scores were associated with early recurrent stroke. Identification of the determinants of early recurrent stroke may lead to better secondary prevention and may help select high-risk patients for further study.

Academic Medical Centers↗

PubMed2004

Myopic versus hyperopic eyes: axial length, corneal shape and optical aberrations.

This study investigated differences in geometrical properties and optical aberrations between a group of hyperopes and myopes (age-matched 30.3+/-5.2 and 30.5+/-3.8 years old, respectively, and with similar absolute refractive error 3.0+/-2.0 and -3.3+/-2.0, respectively). Axial length (AL) was measured by means of optical biometry, and corneal apical radius of curvature (CR) and asphericity (Q) were measured by fitting corneal topography data to biconic surfaces. Corneal aberrations were estimated from corneal topography by means of virtual ray tracing, and total aberrations were measured using a laser ray tracing technique. Internal aberrations were estimated by subtracting corneal from total aberrations. AL was significantly higher in myopes than in hyperopes and AL/CR was highly correlated with spherical equivalent. Hyperopic eyes tended to have higher (less negative) Q and higher total and corneal spherical aberration than myopic eyes. RMS for third-order aberrations was also significantly higher for the hyperopic eyes. Internal aberrations were not significantly different between the myopic and hyperopic groups, although internal spherical aberration showed a significant age-related shift toward less negative values in the hyperopic group. For these age and refraction ranges, our cross-sectional results do not support evidence of relationships between emmetropization and ocular aberrations. Our results may be indicative of presbyopic changes occurring earlier in hyperopes than in myopes.

Adult↗

PubMed2003

Potency of myopic defocus in spectacle lens compensation.

PURPOSE: Previous studies have shown that chick eyes compensate for positive or negative lenses worn for brief periods if the chicks are in darkness the remainder of the time. This study was undertaken to determine whether chicks can compensate for brief periods of lens wear if given unrestricted vision the remainder of the time. Previous studies have also shown that chick eyes alternately wearing positive and negative lenses for brief periods compensate for the positive lenses. The current study sought to determine whether brief periods of positive lens wear can outweigh daylong wearing of negative lenses. METHODS: Chicks wore +6 D or +10 D lenses for between 8 and 60 min/d, in two to six periods and wore either no lenses or negative lenses for the remainder of the 12-hour daylight period. Refraction and ultrasound biometry were performed before and after the 3-day-long experiments. RESULTS: Wearing positive lenses for as little as 12 min/d (six periods of 2 minutes) with unrestricted vision the remainder of the time caused eyes to become hyperopic and reduced the rate of ocular elongation. These effects also occurred when the scene viewed was beyond the far point of the lens-wearing eye and thus was myopically blurred. Even when chicks wore negative lenses for the entire day except for 8 minutes of wearing positive lenses, the eyes compensated for the positive lenses, as though the negative lenses had not been worn. When chicks wore binocular negative lenses for the entire day except for 8 minutes of wearing a positive lens on one eye and a plano lens on the other, the eye wearing the positive lens became less myopic than the eye wearing the plano lens. CONCLUSIONS: Brief periods of myopic defocus imposed by positive lenses prevent myopia caused by daylong wearing of negative lenses. This implies that periods of myopic and hyperopic defocus do not add linearly. If children are like chicks and if the hyperopic defocus of long daily periods of reading predisposes a child to myopia, regular, brief interruptions of reading might have use as a prophylaxis against progression of myopia.

Animals↗

PubMed2004

IQ and the association with myopia in children.

PURPOSE: To evaluate the association between intelligence and myopia in children. METHODS: Cycloplegic refraction and ocular biometry parameters, including axial length, vitreous chamber depth, lens thickness, anterior chamber depth, and corneal curvature were obtained in 1204 Chinese school children aged 10 to 12 years from three schools who were participants in the Singapore Cohort Study Of the Risk Factors for Myopia (SCORM). Intelligence quotient (IQ) was assessed using the nonverbal Raven Standard Progressive Matrix test. RESULTS: After controlling for age, gender, school, parental myopia, father's education, and books read per week, myopia (spherical equivalent [SE]) of at least -0.5 D was associated with high nonverbal IQ (highest quartile) versus low IQ (lowest quartile) (odds ratio = 2.4; 95% confidence interval, 1.7-3.4). Controlling for the same factors, children with higher nonverbal IQ scores had significantly more myopic refractions (-1.86 D for children with nonverbal IQ in the highest quartile compared with -1.24 D for children with nonverbal IQ in the lowest quartile; P = 0.002) and longer axial lengths (24.06 mm versus 23.80 mm; P = 0.022). Nonverbal IQ accounted for a greater proportion of the variance in refraction compared with books read per week. CONCLUSIONS: Nonverbal IQ may be an independent risk factor of myopia, and this relationship may not be explained merely by increased reading (books per week) among myopes. An interesting observation is that nonverbal IQ may be a stronger risk factor for myopia compared with books read per week. The complexity of the relationships between nonverbal IQ, reading, and myopia warrant additional studies to clarify any cause-effect relationship.

Books↗

PubMed2005

Incidence and progression of myopia in Singaporean school children.

PURPOSE: To determine the incidence and progression rates of myopia in young Singaporean children. METHODS: A prospective cohort study, the Singapore Cohort Study of the Risk Factors for Myopia (SCORM), was conducted in two schools in Singapore (1999-2002). Children aged 7 to 9 years (n=981) were followed up over a 3-year period. Cycloplegic autorefraction and biometry parameter measures were performed annually, according to the same protocol. RESULTS: The 3-year cumulative incidence rates were 47.7% (95% confidence interval [CI]: 42.2-53.3), 38.4% (95% CI: 31.4-45.4), and 32.4% (95% CI: 21.8-43.1) for 7-, 8-, and 9-year-old children, respectively. The 3-year cumulative incidence rates were higher in Chinese (49.5% vs. 27.2%) and in 7-year-old compared with 9-year-old children at baseline (47.7% vs. 32.4%), though the latter relationship was of borderline significance after adjustment for race, gender, amount of reading (books/week), and parental myopia (P=0.057). Premyopic children with greater axial lengths, vitreous chamber depths, and thinner lenses were more prone to the development of myopia, after controlling for age, gender, race, reading, and parental myopia. The 3-year mean cumulative myopia progression rates were -2.40 D (95% CI: -2.57 to -2.22) in 7-year-old myopic children, -1.97 (95% CI: -2.16 to -1.78) in 8-year-olds, and -1.71 (95% CI: -1.98 to -1.44) in 9-year-olds. CONCLUSIONS: Both the incidence and progression rates of myopia are high in Singaporean children.

Age Distribution↗

PubMed2005

In a matter of minutes, the eye can know which way to grow.

PURPOSE: The fitting of chick eyes with positive or negative lenses causes eye growth to decelerate or accelerate, respectively, thereby minimizing the imposed blur. This study was conducted to determine whether the eye can initially assess the correct direction of growth or whether it relies on trial and error, reversing its direction if the magnitude of blur increases. The rapid changes in choroidal thickness in response to brief periods of defocus were measured. METHODS: After their eyes were measured by ultrasound biometry, chicks wore either a +10-D lens over one eye for 10 minutes while restrained in the center of a 60-cm drum (to ensure myopic blur), or a negative lens (-7 or -8.6 D) over one eye for 10 minutes or 1 hour in a normal cage environment. They were then kept in darkness until they were remeasured 2 hours, 1 day, or 2 days after the first measurement. Other chicks wore +10 or -8.6-D lenses briefly and were measured several times over the next 7 hours in darkness. RESULTS: Wearing positive or negative lenses for only 10 minutes produced significantly different effects on choroidal thickness measured 2 hours later. Wearing positive lenses for 10 minutes caused an increase in choroidal thickness (in 28 of 32 eyes) and a concomitant decrease in vitreous chamber depth, relative to the amount of change in the untreated fellow eye over the same period. Wearing negative lenses for 1 hour caused significant changes in the opposite direction. Wearing lenses for 2 hours resulted in choroidal changes that persisted in darkness for up to 6 hours after positive lens wear, but returned to normal after negative lens wear. Finally, 1 hour of positive lens wear caused significant inhibition of ocular elongation over the next 2 days. CONCLUSIONS: The eyes of chicks require only a brief period of lens wear to initiate compensation in the appropriate direction. Because the refractive status changes little during the period of lens wear, the authors conclude that eyes can rapidly determine the sign of the imposed blur without resorting to a trial-and-error method.

Accommodation, Ocular↗

PubMed2006

Heritability of macular thickness determined by optical coherence tomography.

PURPOSE: To examine whether genetic factors significantly influence macular thickness in healthy older subjects. METHODS: A classic twin study was performed to compare the correlation of macular thickness between monozygotic (MZ) and dizygotic (DZ) twins in a sample of population-based volunteer twins. The study included 109 white twin pairs from 50 to 80 years of age without evidence of manifest eye disease and corrected visual acuity better than 6/7.5. Dilated macular optical coherence tomography (OCT), fundus photography, clinical examination, ocular biometry, a health-dietary questionnaire, and subjective autorefraction were performed on all subjects. RESULTS: Correlation of retinal thickness was significantly greater between MZ twin pairs than DZ pairs in all macular regions. The MZ-to-DZ correlation was 0.88:0.44 for the foveal region, 0.79:0.47 for the inner macular region, and 0.81:0.50 for the outer macular region. With adjustment for significant covariates and model fitting, final heritability estimates of 85%, 81%, and 81%, respectively, were obtained. A significant correlation between foveal thickness and gender was present, with the men having significantly thicker foveae. There was a significant negative correlation between outer macular thickness and axial length. CONCLUSIONS: This study confirms that macular thickness in older healthy subjects, as measured by OCT, may be affected by genetic factors. Factors such as axial length, gender and age, warrant further examination in larger population-based studies, as variables that may influence macular thickness. This finding suggests an inherited basis of macular thickness and may help in the understanding of the factors that govern macular structure and function.

Aged↗