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PubMed2002

Advances in prenatal screening for Down syndrome: I. general principles and second trimester testing.

BACKGROUND: Down syndrome is one of the most important causes of mental retardation in the population. In the absence of prenatal screening and diagnosis, prevalence at birth in the United States would currently exceed 1:600. The purpose of prenatal screening is to identify those women at the increased risk for an affected pregnancy and to maximize the options available to these women. TESTS AVAILABLE: Second trimester serum screening involves combining the maternal age-specific risk for an affected pregnancy with the risks associated with the concentrations of maternal serum alpha-fetoprotein (MSAFP), unconjugated estriol (uE3), and human chorionic gonadotropin (hCG) (triple testing). A forth analyte, inhibin-A (INH-A), is increasingly being utilized (quadruple testing). Optimal second trimester screening requires the integration of a number of clinical variables, the most important of which is an accurate assessment of gestational age. In addition to Down syndrome, the triple and quadruple tests preferentially identify fetal trisomy 18, Turner syndrome, triploidy, trisomy 16 mosaicism, fetal death, Smith-Lemli-Opitz syndrome, and steroid sulfatase deficiency. Some programs modify the Down syndrome risks generated through maternal serum screening tests with fetal biometric data obtained by ultrasound. Other second trimester tests have shown promise, including the analysis of maternal urine and fetal cells in the maternal circulation, but none are in routine clinical use. CONCLUSION: The second trimester triple and quadruple tests provide benchmarks for evaluating new screening protocols. The combination of fetal biometry, new test development as well as clarification of the role of co-factors that affect the concentrations of analytes in existing tests should lead to greater efficacy in second trimester screening for Down syndrome.

Biomarkers↗

PubMedDate not supplied

Angle recess area decreases with age in normal Japanese.

PURPOSE: To investigate prospectively the relationships between anterior chamber angle configuration and refractive error, axial length, age, and body height in the Japanese. METHODS: We studied 65 eyes of 65 subjects (30 men, 35 women) who were either patients at the Ophthalmology Department of Mie University or volunteers. The 65 subjects underwent a complete eye examination, A-scan biometry, and ultrasound biomicroscopy. Images were exported to an IBM-compatible personal computer in PCX format. The angle recess area (ARA) was measured using a software program of our own design. RESULTS: The ARA decreased with age in all quadrants of all eyes. In older individuals, the angle in the superior quadrant was significantly narrower than in the other quadrants. The ARA correlated directly with anterior chamber depth (P < .001), axial length (P < .001), and body height (P = .003), and inversely with age (P < .001) and refractive error (P = .003) in pairwise analysis. Multivariate analysis revealed a significant association between ARA and anterior chamber depth (P < .001), axial length (P = .016), and younger age (P = .043). CONCLUSIONS: The anterior chamber area narrows with age, especially in the superior quadrant. Narrowing of the angle in Japanese is associated with older age, shorter axial length, and shallower anterior chamber depth. We hypothesize that because of the increasing prevalence of axial myopia in younger Japanese, angle-closure glaucoma could become less common in Japan in the future.

Adult↗

PubMed2001

Sonographic prediction of twin birth weight discordance.

OBJECTIVE: To assess the accuracy of sonographic prediction of clinically significant twin birth weight discordance (25% or greater) and to determine whether this accuracy is affected by defined fetal and maternal variables. METHODS: Using an established database, we reviewed 338 twin gestations delivered over 10 years as a retrospective cohort. Estimation of fetal weight was calculated by applying the Hadlock formula using composite fetal biometry. Intertwin weight discordance was calculated as the difference in the estimated or actual twin weights (A-B) divided by the weight of the larger twin and was expressed as a percentage. Statistical evaluation included validity (sensitivity, specificity, and predictive values) and reliability assessment of ultrasonographic measurements (intraclass correlation coefficients). Multivariable analysis was performed. RESULTS: Of 338 twin gestations, 192 (57%) twin pairs met inclusion criteria. Sonographic prediction of actual intertwin birth weight discordance of 25% or greater had a sensitivity of 55%, specificity of 97%, positive predictive value of 82%, and negative predictive value of 91%. The reliability of estimating intertwin birth weight discordance by ultrasonography was moderately high (intraclass correlation coefficient =.700; 95% confidence interval [CI].620,.765). Multivariable analysis revealed no significant effects of individual maternal or fetal factors on the accuracy of ultrasonographic prediction of intertwin birth weight discordance. CONCLUSION: Sonographic prediction of actual intertwin birth weight discordance of 25% or greater within 16 days of delivery appears to be a valid and reliable method for clinical use. Predictive accuracy is independent of other identifiable maternal or fetal variables.

Adolescent↗

PubMed2001

Interval between fetal measurements in predicting growth restriction.

OBJECTIVE: To determine the influence of the interval between fetal measurements on performance of fetal growth velocity for predicting infants with anthropometric features of fetal growth restriction (FGR). METHODS: Two hundred seventy-four low-risk women had serial fetal biometry at scheduled intervals. Growth velocity of the fetal abdominal area for each was calculated with 2-, 4-, and 6-week scan intervals in which the second measurement was the last scan before delivery. Fetal abdominal area velocity over a 4-week interval in the early third trimester also was included. Fetal growth restriction was defined as skinfold thickness under the tenth percentile, ponderal index under the 25th percentile, midarm circumference-to-occipitofrontal circumference ratio of under -1 standard deviation (SD). Test performance was expressed as likelihood ratios with 95% confidence intervals (CI). RESULTS: Fetal abdominal area velocity calculated over a 4-week interval predicted FGR with a likelihood ratio of 10.4 (95% CI 3.9, 26) for skinfold thickness; 9.5 (95% CI 4.6, 19) for ponderal index; and 4.7 (2.3, 8.4) for midarm circumference-to-occipitofrontal circumference ratio. Intermeasurement intervals of 6 weeks had a likelihood ratio of 8.5 (95% CI 4, 17) for skinfold thickness; 7.5 (95% CI 3.4, 16.1) for ponderal index; and 14 (6.7, 28) for midarm circumference-to-occipitofrontal circumference ratio. The likelihood ratios for the 2-week interval and the early third trimester 4-week interval were all less than 5. CONCLUSION: Four- and 6-week measurement intervals were useful for predicting infants with FGR and were superior to a 2-week interval. Fetal growth velocity is influenced by proximity of the last fetal measurement to date of delivery, which adversely affects clinical use of growth velocity for predicting FGR.

Adult↗

PubMed2001

Intrauterine blood flow and long-term intellectual, neurologic, and social development.

OBJECTIVE: To study the long-term effects of severely abnormal (absent or reversed diastolic) blood flow in the umbilical artery associated with fetal growth restriction on postnatal intellectual, neurologic, and social development. METHODS: Absence or reversal of diastolic blood flow in the umbilical artery was found in 38 consecutive growth-restricted fetuses as determined by biometry and Doppler ultrasound between 1988 and 1992. The 23 infants surviving the prenatal and perinatal period who could be tested were compared at school age with a group of children born at the same gestational age after normal intrauterine growth. They were tested for intellectual, neurologic, and social development by a test battery including the Kaufmann Assessment Battery for Children, Man-Drawing Test, Child Behavior Checklist, Zürich Neuromotor Test, and neuropediatric testing. RESULTS: Intellectual development was significantly better in the control group compared with the study group. In addition, Zürich Neuromotor testing and neuropediatric testing showed significantly better development of control children compared with the study group in 20% of the items tested. There was no detectable difference in social development as measured by the Child Behavior Checklist. CONCLUSION: Severely reduced blood flow to the fetus associated with growth restriction was followed by long-term impairment of intellectual development and partial neurodevelopmental delay.

Adult↗

PubMed2002

Combined second-trimester biochemical and ultrasound screening for Down syndrome.

OBJECTIVE: To evaluate the efficacy of a Down syndrome screening protocol that combines second-trimester maternal serum analytes and the continuous ultrasound measures of nuchal fold thickness and proximal long bone length. METHODS: Ultrasound measurements of nuchal fold, femur length, and humerus length were reviewed for 72 second-trimester Down syndrome and 7063 unaffected fetuses. Derived statistical variables for these parameters were entered into a multivariable Gaussian model together with the statistical variables used in the "quad" test (maternal serum alpha-fetoprotein, unconjugated estriol, human chorionic gonadotropin, and inhibin A). Maternal age-specific sensitivities, false-positive rates, and positive predictive values were generated together with receiver operating characteristic curves. Overall efficacy of ultrasound screening alone, the quad test, and the combination of the ultrasound and quad test were compared using a 1:270 second-trimester risk cutoff applied to 1999 US births. RESULTS: Using ultrasound, a sensitivity of 79.9% and false-positive rate of 6.7% may be achieved (positive predictive value: 1 in 42). The quad test has a sensitivity of 81.5% and false-positive rate of 6.9% (positive predictive value: 1 in 42). The combination of the quad test with nuchal fold and long bone measurements may achieve 90% sensitivity and a 3.1% false-positive rate (positive predictive value: 1 in 18). CONCLUSION: Combining second-trimester serum testing and fetal biometry is a feasible approach to Down syndrome screening, compatible with current obstetric practice. This modality is substantially more effective than either serum screening or ultrasound alone. Efficacy may be comparable to that reported for combined first- and second-trimester (integrated) screening.

Adult↗

PubMed2003

Short delay of delivery to allow corticosteroid administration in a case of preterm antepartum eclampsia.

BACKGROUND: The current recommendation for management of antepartum eclampsia is to take steps to deliver the fetus after stabilization of the maternal condition. We delayed delivery for 60 hours in a case of antepartum preterm eclampsia to allow administration of corticosteroids for fetal lung maturity enhancement. CASE: A primigravida presented with eclamptic seizure at 29 weeks' gestation without focal neurological deficits. Clinical and laboratory assessment ruled out the presence of the syndrome of hemolysis, elevated liver enzymes, low platelets; abruption; disseminated intravascular coagulation; or acute renal failure. The fetal biometry was appropriate for gestational age, and there was a normal amount of amniotic fluid. Fetal testing was reassuring. Expectancy with intravenous magnesium sulfate infusion was continued for 60 hours, allowing administration of a course of corticosteroids for enhancement of fetal lung maturity. Maternal and neonatal outcomes were satisfactory. CONCLUSION: A 2-day delay in delivery in selected patients with preterm antepartum eclampsia allows administration of steroids for fetal lung maturity enhancement.

Adult↗

PubMed2002

Validation of the Quintero staging system for twin-twin transfusion syndrome.

OBJECTIVE: To validate an established staging system for twin-twin transfusion syndrome. METHODS: Prospective observational study in a tertiary referral fetal medicine center of 52 consecutive cases of twin-twin transfusion syndrome. Each pregnancy was assessed longitudinally for a variety of prognostic factors including fetal biometry, amniotic fluid volume, arterial and venous Doppler sonogram abnormalities, and the presence of hydrops. Data were used to determine stage at diagnosis and first treatment, and worst stage throughout pregnancy. Perinatal outcome was assessed by stage. Management comprised serial amnioreduction, septostomy, selective reduction, or delivery, alone or in combination. RESULTS: Median gestation at presentation and first treatment were both 21 weeks (range 14-34 and 15-34), and at delivery it was 29 weeks (range 16-40). Sixty-three percent of pregnancies (33 of 52) were at least stage III at presentation. Forty-five percent of pregnancies (22 of 49) progressed to a more advanced stage. Overall survival was 47% (47 of 100), with no difference between donor and recipient fetuses (40% [20 of 50] versus 54% [27 of 50] [chi(2) P =.5]). Survival rates were 58% (15 of 26), 60% (six of ten), 42% (20 of 48), 43% (six of 14), and 0% (none of two) for stages I-V, respectively, with no significant influence of stage at presentation on survival. Survival was poorer where stage increased, versus decreased (27% [12 of 44] versus 94% [17 of 18] chi(2) P <.001). Kaplan-Meier survival curves indicated that staging at presentation identified pregnancies at greater risk of earlier rather than later gestational perinatal loss. CONCLUSION: The Quintero staging system did not distinguish good from bad outcome at presentation, and thus should be used with caution in guiding initial management of twin-twin transfusion syndrome. However, prognosis was influenced by a change in stage, and pregnancies progressing to higher stage disease were at increased risk of earlier perinatal loss. Staging may thus be more useful in monitoring disease progression.

Adult↗

PubMed1997

Sonographic examination does not predict twin growth discordance accurately.

OBJECTIVE: To assess the accuracy of estimating birth weight among twins with discordancy (intra-pair difference in actual birth weight of more than 25%) and to determine the relative accuracy of an intra-pair difference in abdominal circumference (delta AC) of 20 mm or more or in estimated fetal weight (delta EFW) of 25% or more for the identification of discordant growth in twins. METHODS: Over a 6-year period, we identified all non-anomalous twin pairs with gestational ages greater than 23 weeks and sonographic examinations within 3 weeks of birth. Ultrasonographic biometry of both twins included AC, head circumference, and femur length; these indices were used to estimate fetal weight by Hadlock's formula. Likelihood ratios, receiver-operating characteristic curves, and prediction limits were applied to assess the accuracy of the two diagnostic methods to predict an abnormal outcome. RESULTS: A total of 242 twin pairs were studied. The mean gestational age among the 21 twins with abnormal growth (30.6 +/- 4.6 weeks) was significantly less than among the 221 twins with normal growth (33.2 +/- 4.0 weeks) (P < .005). The biometric measurements of fetal parts, sonographic estimate of fetal weight, and actual birth weight for both fetuses were significantly less for discordant twin pairs (P < .05). The accuracy of predicting birth weight, as determined by mean error and percentage of the estimate within 10% of the actual weight, was similar between the groups. Receiver-operating characteristic curves showed that both diagnostic tests yielded areas under the two curves not significantly different from the area under the nondiagnostic line (P > .05). Most important, prediction limit calculations indicated that a 90% certainty that the actual birth weight discordance was at least 25% was achievable only if delta AC was 172 mm or greater or delta EFW was 112% or more. CONCLUSION: The most popular current methods (difference in AC or EFW) for predicting discordant growth in twin gestations have limited accuracy when held to a standard for discordance that requires a birth weight difference of at least 25%.

Birth Weight↗

PubMed1997

Fetal transcerebellar diameter in Down syndrome.

OBJECTIVE: To determine whether cerebellar hypoplasia in Down syndrome is established and clinically recognizable in the second trimester of pregnancy and to evaluate the screening utility of transverse cerebellar diameter measurements for Down syndrome fetuses. METHODS: Ultrasonographic biometry data obtained before genetic amniocenteses on 42 fetuses with Down syndrome and 1161 karyotypically normal fetuses were analyzed. Mean transverse cerebellar diameters stratified by gestational age were compared. A regression equation relating transverse cerebellar diameters to gestational age was calculated for 387 normal fetuses and applied to the remaining normal (n = 774) and all Down syndrome fetuses. Ratios of observed to expected cerebellar diameters were calculated. Sensitivity, specificity, and positive predictive values were calculated for various cutoff points and Down syndrome prevalences. RESULTS: Cerebellar diameters in Down syndrome fetuses were smaller than in normal controls at all gestational ages (P < .005) by an average of 0.67-0.87 mm. A ratio of 0.92 for observed/expected cerebellar diameters yielded a sensitivity of 21%, specificity of 95%, and positive predictive values of 1.66% and 0.56% in populations with a risk for Down syndrome of one in 250 and one in 750, respectively. CONCLUSIONS: Cerebellar hypoplasia is developmentally established and sonographically recognizable in second-trimester Down syndrome fetuses. However, cerebellar size differences between normal and Down syndrome fetuses are too small to be clinically useful.

Anthropometry↗

PubMed1997

Biometric investigation of changes in the anterior eye segment during accommodation.

Non-invasive biometry of the anterior structures of the human eye can be performed with unprecedented precision of 8-10 microns and a resolution of approximately 9 microns by partial coherence interferometry, which has the potential to assess the effect of cycloplegia on the ocular components of the anterior eye segment, to further improve the precision to 1-2 microns by the use of these agents and to quantify the amount of residual accommodations in different states of cycloplegia. In addition, the anterior chamber depth, the thickness of the crystalline lens, their changes during accommodation, as well as the movement of the anterior and posterior lens pole during accommodation can be quantified objectively and accurately to investigate the mechanism of accommodation.

Accommodation, Ocular↗

PubMed1997

Office procedures. Obstetric ultrasonography.

Some clinician physicians who provide perinatal care find that they have the motivation and practice volume to learn diagnostic ultrasonographic skills. These skills may be limited to labor and delivery applications or may extend to performance of the standard antepartum obstetric ultrasound examination. Limited skills include the diagnosis of fetal life number, presentation, amniotic fluid assessment, and placental localization. The standard antepartum obstetric ultrasound examination adds fetal biometry and a detailed assessment of fetal anatomy.

Certification↗

PubMed1995

Antenatal assessment of twin gestation.

We have identified that twin gestation presents considerable risks to the well-being of both infants that can be traced to either related maternal or intrinsic fetoplacental factors. A protocol for the assessment of twin gestation is established, beginning with a basis in ultrasound identification of twinning and correct gestational dating. Because most hazards for twins are related to abnormal growth, discrepant growth between twins, and abnormalities of placentation, the approach to assessing well-being requires good serial biometry of twins. This critical review addresses the individual and combined application of standard tests used for evaluation of intrauterine health in single pregnancies: (1) ultrasound fetal growth curves; (2) Doppler velocimetry of the umbilical artery; (3) nonstress tests; (4) amniotic fluid assessment and (5) biophysical profile testing. The best current evidence suggests that there are clear deficiencies in the basis for growth nomograms for twin gestations, and with the exception of femur length, most individual anatomic measurements start to deviate from singleton standards between 21 and 30 weeks' gestation. Regardless of formulae used, estimated fetal weight provides the best discriminator for discordant growth. Dynamic assessment of fetal well-being is best provided by a combination of Doppler velocimetry and nonstress testing. Semiquantitative amniotic fluid assessment, other than establishing pathological conditions (eg, twin transfusion syndrome), is problematic and difficult to reproduce. Inadequate data exist to establish the value of the biophysical profile in twins. Given the limitations of present knowledge, serial assessment of twins beginning in the midtrimester with ultrasound observation, and adding combinations of Doppler velocimetry and nonstress testing in the third trimester, seems to represent the most reasonable current clinical approach to twin well-being.

Diseases in Twins↗

PubMed1982

Nanophthalmos with uveal effusion: clinical and embryologic considerations.

Three brothers were found to have nanophthalmos as evidenced by marked hyperopia, decreased global axial length, and shallow anterior chambers. The thickness of the lens, measured with A-scan ultrasound biometry in two cases, was much greater than normal. Choroidal thickening with shallow retinal detachments without breaks was found in those patients. Fluorescein angioscopy demonstrated leaks beneath the serous retinal detachments in one. The spontaneous presence of choroidal effusions and retinal detachments in nanophthalmic patients has been reported only rarely. The present findings emphasize that careful examination of the posterior segment should be done prior to anterior segment surgery in these patients to alert the surgeon to the possibility of serious intra- and post-operative choroidal effusions and retinal detachments. An attempt is made to explain some of the clinical findings in nanophthalmos by extrapolating from results obtained on experimental animals. It is postulated that the increased lens size in nanophthalmos may be due to the abnormal accumulation of a factor influencing lens fiber differentiation. The overall small size of the eye may be the result of the formation of a smaller than usual optic vesicle anlage.

Aged↗

PubMed1998

Ophthalmologic findings in long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency caused by the G1528C mutation: a new type of hereditary metabolic chorioretinopathy.

OBJECTIVE: The purpose of the study was to determine the nature and course of ophthalmic abnormalities in long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency, a recently discovered disorder of mitochondrial fatty acid beta-oxidation. STUDY DESIGN: The study design was a cohort (case series). PARTICIPANTS: A retrospective review of the records of 15 children who had died during their first 2 years was performed. Also performed were a longitudinal reanalysis and cross-sectional clinical examination of four long-term survivors aged 5 to 31 years. MAIN OUTCOME MEASURES: Visual acuity, refraction, visual fields, ophthalmoscopy, fluorescein angiography, biometry, corneal topography, electroretinography (ERG), visual-evoked potentials (VEPs), color vision, and dark adaptation were measured. RESULTS: In seven children, ophthalmoscopic findings were within normal limits at 3 days to 13 months of age (median, 4.8 months). In 11 children, a granular retinal pigment epithelium (RPE), with or without pigment clumping in the macula, was seen at 4 months to 5 years of age (median, 9 months). Two long-term survivors, 16 and 31 years of age, eventually had circumscribed atrophy of the choroid, RPE, and retina, which coincided with a posterior staphyloma type 1. They had progressive axial myopia starting at 6 and 12 years of age and later paracentral scotomas leading to poor central vision. They suffered from early difficulty with mesopic vision, glare, and a severe generalized color vision deficiency that started as a tritanomaly. A third survivor was mildly myopic at 5 years of age. All four surviving patients had visually insignificant, flake-like supranuclear opacities in the lens. The ERG initially was normal but deteriorated during the first decade and later was unrecordable. The VEP responses remained fairly normal. Initially, angiography showed no blockade of the choroidal fluorescence because of the thin RPE. Filling of choroidal vessels was delayed, and the choriocapillaris and, later, larger choroidal vessels in the posterior pole became nonperfused. CONCLUSIONS: In LCHAD deficiency, the fundus is normal at birth (stage 1). Soon, however, pigment dispersion occurs in the RPE (stage 2), followed by circumscribed chorioretinal atrophy, occlusion of choroidal vessels, and deterioration of central vision, often with relative sparing of the peripheral fundus (stage 3). Finally, posterior staphylomas and central scotomas may develop (stage 4). Developmental cataract, progressive myopia, and deterioration of visual fields and color vision are new findings in LCHAD deficiency. The chorioretinopathy and abnormal ERG precede the development of myopia and posterior staphyloma, which, in turn, coincide with the loss of macular vision. The authors postulate that the RPE or choriocapillaris is primarily affected. Awareness of the characteristic ocular features is important because of an opportunity for dietary treatment, genetic counseling, and prenatal diagnosis.

3-Hydroxyacyl CoA Dehydrogenases↗

PubMed1999

Axial length decrease accompanying successful glaucoma filtration surgery.

OBJECTIVE: To evaluate change in axial length measurement after successful glaucoma filtering surgery. DESIGN: Retrospective consecutive case series. PARTICIPANTS: Sixty-two patients with phakia who underwent primary trabeculectomy. INTERVENTION: The A-scan biometry of ocular axial length before and after trabeculectomy. MAIN OUTCOME MEASURES: Changes in ocular axial length measurement after successful trabeculectomy were analyzed. RESULTS: The mean decrease in axial length measurement was 0.423 mm (range, -2.8 to +0.5 mm). Regression analysis yielded a statistically significant association between decrease in axial length measurement and age (P = 0.0001) and post-trabeculectomy intraocular pressure decrease greater than 30 mmHg (P = 0.01). Analysis of variance revealed a significant association between decrease in axial length measurement and use of antimetabolite (P = 0.005). Pseudophakic axial length measurements increased an average of 0.275 mm compared to the axial length after trabeculectomy and before cataract surgery. CONCLUSIONS: Axial length measurement decreased in 32 of 62 eyes after successful initial trabeculectomy. A decrease in axial length measurement may have an influence on intraocular lens calculations. Therefore, the authors recommend that an axial length measurement be obtained on phakic eyes before an initial trabeculectomy to reduce the risk of an inaccurate intraocular lens power calculation based on post-trabeculectomy axial length measurements.

Adult↗

PubMed1983

An accurate and simple method for megavoltage radiation therapy of retinoblastoma.

A simple but highly accurate irradiation method for the "conservative" treatment of retinoblastoma has been developed at the Utrecht Retinoblastoma Centre. Treatment is carried out with a 6 MV or 8 MV linear accelerator using a lateral D-shaped field of 26 X 32 mm2. This D-shaped field is specially contoured to include the entire retinal surface or vitreous and 10 mm of the anterior optic nerve and to protect the sensitive anterior structures of the eye, particularly the lens, as much as possible. Accurate positioning of the sharply collimated treatment field is easily done by magnetic fixation of the eye to the beam defining collimator by use of a low vacuum contact lens. As the fixed eye is located in the isocentre of the accelerator, the radiation beam can be directed at any angle by simple rotation of the gantry or table, without alteration of the position of the eye within the treatment field. Simultaneous irradiation of bilateral retinoblastoma is just as easily possible and can be done with the same accuracy by fixation of both eyes with contact lenses and alternately applying two opposing lateral fields. Prior to treatment, the axial dimensions of each eye are determined by ultrasonic biometry to ascertain the exact volume to be irradiated.

Anesthesia↗

PubMed2004

[Biometric study of acute-angle-closure glaucoma using Orbscan and echography].

PURPOSE: To study acute-angle-closure glaucoma (AACG) biometry using Orbscan and echography. MATERIAL AND METHODS: We prospectively studied 200 normal eyes of 100 patients (including eyes with ametropia), 50 eyes of 25 patients before peripherial YAG laser iridotomy, 25 phakic eyes of 25 patients with a history of acute-angle-closure glaucoma (AACG) in the fellow eye. Both plane and polynomial modes of reconstruction of the iridocorneal angle measurement were analyzed. Biometric measurements of the three groups were compared. Biometric measurements (i.e., iridocorneal angle, anterior chamber depth, axial length, and lens thickness) and subjective spherical equivalent were correlated with the etiological classification. RESULTS: Age, sex, iridocorneal angle, anterior chamber depth, lens thickness, axial length and subjective spherical equivalent were significantly different in the three groups (p<0.002). The polynomial iridocorneal angle measurement was 43.4 degrees in the normal group, 36.5 degrees in the iridotomy group, and 28.4 degrees in the AACG group (p<0.001). Iridocorneal angle measurement correlated with the other biometric measurements (rs>0.51; p<0.001) and with the etiological classification (rs< or =0.68; p<0.001). The anterior chamber depth measurement obtained by Orbscan or echography was the best parameter for predicting ACCG (rs=0.77; p<0.001). CONCLUSION: The anterior chamber depth and polynimial iridocorneal angle obtained using the Orbscan device appears to be useful in predicting acute-angle-closure glaucoma.

Acute Disease↗