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PubMed1990

Pathophysiology of congenital diaphragmatic hernia: I. Renal enlargement suggests feedback modulation by pulmonary derived renotropins--a unifying hypothesis to explain pulmonary hypoplasia, polyhydramnios, and renal enlargement in the fetus/newborn with congenital diaphragmatic hernia.

Survival of newborns with congenital diaphragmatic hernia (CDH) is largely dependent on the severity of pulmonary hypoplasia (PH) present at birth. Intrathoracic compression by the herniated abdominal viscera is thought to be the primary factor involved in the pathogenesis of the PH in CDH. Humoral and/or amniotic pulmonary growth factors (PGF) have been hypothesized to play a role in normal fetal pulmonary development and may be involved in the pathogenesis of CDH as well. The hypothesis of this paper is that growth of the fetal lung is stimulated by a PGF produced by the kidneys, which is modulated by a feedback signal from the lungs, a pulmonary derived renotropin (PDR). In the fetus with CDH, the lungs may be unable to respond to PGF due to compression by the herniated abdominal viscera. Theoretically, PH associated with CDH would maximally stimulate this feedback loop to release more PDR, resulting in continual stimulation of the kidneys and renal enlargement. If such a scheme plays a role in the in utero pathophysiology of CDH, then newborns with CDH should have enlarged kidneys. To investigate this hypothesis, we reviewed 30 autopsy cases of newborns with CDH and analyzed their kidney weights versus body weights, using historical data as control. Kidney weights in CDH cases were greater than the control population in 77% of the cases; 57% of kidney weights were more than one standard deviation above control values. Adjusted group mean kidney weights were 29.8 g (+/- 1.0 SE) in CDH cases and 25.9 g (+/- 1.5 SE) in the control population (P less than .04). These data support our hypothesis and demonstrate that in newborns with CDH and morphologically normal kidneys, there is significant renal enlargement associated with CDH. The presumed mechanism of this renal enlargement, as well as its relationship to normal and aberrant pulmonary growth and regulation are discussed. If such a selective PGF exists, its therapeutic implications for fetuses and newborns with PH are considerable.

Analysis of Variance↗
PubMed1998

Increased bone resorption in patients with Crohn's disease.

BACKGROUND: Patients with Crohn's disease are at risk of osteoporosis and premature fracture. However, the pathophysiology underlying bone loss remains poorly understood and the optimum treatment has not been established. AIM: To investigate mechanisms of bone loss in Crohn's disease using biochemical markers of bone turnover. METHODS: Bone mineral density was measured at the hip and spine using dual-energy X-ray absorptiometry in 117 patients (48 male) with Crohn's disease. Bone turnover was assessed by measuring serum osteocalcin (BGP), pro-collagen carboxy-terminal propeptide (PICP), bone specific alkaline phosphatase (BALP) and urinary deoxypyridinoline (DPD); and compared to age-matched healthy controls (n = 28). RESULTS: Bone mineral density was reduced (z-score < -1) in 48 (41%) patients with Crohn's disease. Mean values for bone formation markers in patients with Crohn's disease were all within the normal reference range (BGP 8.92 (+/- 3.23) ng/mL (normal range 3.4-10.0), BALP 17.6 (+/- 12.6) U/L (normal range 11.6-43.3), PICP 95.1 (+/- 46.5) ng/mL (normal range 69-163)) and were not significantly different to the control population. However, mean urinary DPD was significantly higher in patients with Crohn's disease compared to healthy controls (10.97 (+/- 9.22) nM DPD/mM creatinine vs. 5.02 (+/- 1.03) nM DPD/mM creatinine, difference in means = 5.95, 95% CI: -9.6 to -2.3, P = 0.00001) and compared to the UK reference range DPD levels were increased in 74 (63%) patients. CONCLUSIONS: Bone resorption as evidenced by urinary DPD was frequently increased in patients with Crohn's disease and was significantly higher than in an age-matched control population. The high levels of urinary DPD suggest increased bone collagen degradation may contribute to osteoporosis in patients with Crohn's disease. These results suggest anti-resorptive agents such as the bisphosphonates may be effective treatment for osteoporosis in Crohn's disease.

Adult↗
PubMed2006

Sagittal alignment of the spine and pelvis in the presence of L5-s1 isthmic lysis and low-grade spondylolisthesis.

STUDY DESIGN: A radiographic study of 82 patients with L5-S1 spondylolysis or spondylolisthesis of less than 50% displacement of L5 on S1. OBJECTIVE: To measure and describe the sagittal alignment of the spine and pelvis in patients with spondylolysis before the development of a large secondary deformity associated with progression of the spondylolisthesis. SUMMARY OF BACKGROUND DATA: Several publications have addressed the alignment of the spine and pelvis as an important factor in the occurrence, symptomatology, progression, and treatment of spondylolysis and spondylolisthesis. To our knowledge, this is the first report to systematically document the native sagittal alignment of affected patients and compare them to a large control population. MATERIALS AND METHODS: The sagittal alignment in this cohort of 82 patients was compared with a control population of 160 patients without symptoms of back pain or radiographic abnormalities of the spine and pelvis that was the subject of a previous study. RESULTS: Patients with spondylolysis and low-grade spondylolisthesis demonstrate increased pelvic incidence, increased lumbar lordosis, but less segmental extension between L5 and S1 than in a normal population. CONCLUSIONS: These data suggest that differences in the sagittal alignment of the spine and pelvis may influence the biomechanical environment that results in the development of spondylolysis and progressive spondylolisthesis.

Adolescent↗
PubMed2002

Factors explaining variance in perceived pain in women with fibromyalgia.

BACKGROUND: We hypothesized that a substantial proportion of the subjectively experienced variance in pain in fibromyalgia patients would be explained by psychological factors alone, but that a combined model, including neuroendocrine and autonomic factors, would give the most parsimonious explanation of variance in pain. METHODS: Psychometric assessment included McGill Pain Questionnaire, General Health Questionnaire, Hospital Anxiety and Depression Rating Scale, Eysenck personality Inventory, Neuroticism and Lie subscales, Toronto Alexithymia Scale, and Multidimensional Health Locus of Control Scale and was performed in 42 female patients with fibromyalgia and 48 female age matched random sample population controls. A subgroup of the original sample (22 fibromyalgia patients and 13 controls) underwent a pharmacological challenge test with buspirone to assess autonomic and adrenocortical reactivity to serotonergic challenge. RESULTS: Although fibromyalgia patients scored high on neuroticism, anxiety, depression and general distress, only a minor part of variance in pain was explained by psychological factors alone. High pain score was associated with high neuroticism, low baseline cortisol level and small drop in systolic blood pressure after buspirone challenge test. This model explained 41.5% of total pain in fibromyalgia patients. In population controls, psychological factors alone were significant predictors for variance in pain. CONCLUSION: Fibromyalgia patients may have reduced reactivity in the central sympathetic system or perturbations in the sympathetic-parasympathetic balance. This study shows that a biopsychosocial model, including psychological factors as well as factors related to perturbations of the autonomic nervous system and hypothalamic-pituitary-adrenal axis, is needed to explain perceived pain in fibromyalgia patients.

Journal Article↗
PubMed1996

[Properties of inbred Drosophila melanogaster lines obtained from a population selected for an increased rate of embryonic development].

Two heterogeneous Drosophila melanogaster populations were subjected to selection for an increased rate of embryonic development by picking out the first 10% of hatching larvae. After repeating this procedure in 15 generations, "fast" populations were obtained, in which the duration of embryonic development at high temperature (31-32 degrees C) was 30-40 min less than in nonselected control populations. The results of preliminary experiments on substituting the second and third chromosomes in the selected and control populations provide evidence that selected genes responsible for accelerated development are located on the second chromosome. Inbreeding in 12 generations of selected populations was used to obtain about 40 lines homozygous, in particular, at the alcohol dehydrogenase gene. In four lines, the developmental rate was higher than in a homozygous control line, but others did not differ from control or developed more slowly. The duration of embryonic development at 32 degrees C in fast lines was 50-70 min shorter than in control, but this difference was significantly less at lower temperatures (25 and 17 degrees C). Hence, high temperature is primarily a factor in providing conditions for the expression of genes determining the developmental rate, rather than a factor of selection for these genes. It is suggested that selected genes modify developmental rate dependence on temperature.

Animals↗
PubMed2006

Tumour necrosis factor gene complex polymorphisms in chronic obstructive pulmonary disease.

We aimed to examine the role of tumour necrosis factor gene complex polymorphisms in subjects with chronic obstructive pulmonary disease (COPD). We hypothesized that individuals possessing polymorphic variants associated with higher tumour necrosis factor (TNF) secretion would be more susceptible to and/or have more severe disease. Patients with COPD and population controls underwent detailed clinical phenotyping. Genotyping for the tumour necrosis factor-308 and the lymphotoxin alpha NcoI (LTalpha polymorphisms was carried out by 'blinded' laboratory staff. Three hundred and sixty one individuals (220 cases and 141 controls) were recruited. We showed an association between the LTalphaNcol polymorphism and forced vital capacity (FVC) in a population of older adults with and without COPD. The LTalphaNcol*2 allele was associated with poorer lung function, under a codominant model, with a fall in FVC (expressed as a percentage of its predicted value) of 3.7% for each copy of the LTalphaNcol*2 allele possessed (for FVC, regression coefficient (95% CI)=-3.73(-7.01 to -0.44), P=0.026; for FEV(1) regression coefficient=-3.56(-7.80 to 0.70), P=0.101. However, there was no difference in genotype distribution between the case and control populations. This study adds weight to the suggestion that the TNF gene complex is involved in physiological alterations (FVC) that may affect the development and severity of COPD. The absence of a significant association between the TNF gene-complex polymorphisms in this study does not rule out a modest effect of these polymorphisms on the risk of COPD, as much larger studies are needed to detect modest gene effects on binary disease endpoints.

Aged↗
PubMed1995

School sex education: an experimental programme with educational and medical benefit.

OBJECTIVES: To develop and teach a school sex education programme that will lead to a decrease in sexual activity. DESIGN: A matched internal and external control experiment, comparing control populations which received their own sex education programmes with populations which received a novel sex education intervention that included medical and peer led teaching. SETTING: Comprehensive secondary schools; control and intervention populations within Devon, and distant controls from rural, semiurban, and urban areas of England excluding major conurbations. SUBJECTS: Schoolchildren were taught from age 12 to 16; three successive cohorts of students were evaluated in school year 11 (mean age 16.0). MAIN OUTCOME MEASURES: Questionnaire conducted under "examination conditions" and invigilated by the research team and other trained medical staff. RESULTS: In the intervention population, progressive increase in knowledge related to contraception, sexually transmitted diseases, and prevalence of sexual activity (chi 2 (trend) P < 0.001 for all three series); relative increase between intervention and control populations in knowledge, relative decrease in attitudes suggesting that sexual intercourse is of itself beneficial to teenagers and their relationships, relative decrease in sexual activity, and relative increase in approval of their "sex education" (relative risk > 1.00 with 95% confidence limits not including 1.00 for all series and for comparisons with both control populations); odds ratio (control v programme) for sexual activity of 1.45, controlling for sociodemographic variables. CONCLUSION: School sex education that includes specific targeted methods with the direct use of medical staff and peers can produce behavioural changes that lead to health benefit.

Adolescent↗
PubMed1994

An investigation of gene-environment interaction in the etiology of rheumatoid arthritis.

The etiology of rheumatoid arthritis is explained by both genetic and hormonal environment factors. Using a survey of twins conducted in the British Isles in 1989, the authors have investigated the extent of a possible genetic-hormonal environment interaction in conferring susceptibility for rheumatoid arthritis. This was done by comparing the hormonal history of three groups of cases and controls: 1) disease-discordant monozygotic twins, thus matching cases and controls for genetic susceptibility; 2) disease-discordant dizygotic twins; and 3) a group of twins with rheumatoid arthritis who were age matched to population controls. When the medical histories of twins with rheumatoid arthritis were compared with those of population controls, both breast feeding and infertility problems appeared to be risk factors for the disease (odds ratios = 2.01 and 4.09, respectively). Also, oral contraceptive use appeared to have a protective effect (odds ratio = 0.43). However, when both monozygotic and dizygotic twins were compared, these effects were either less apparent or nonexistent. Our results therefore suggest that there does not exist any evidence of strong interaction between genetic and hormonal environment factors. More notably, in the absence of such an interaction, the comparison of both monozygotic and dizygotic discordant twins was overmatched and therefore of low power. The extent of any overmatching was measured using the kappa statistic.

Adult↗
PubMed2004

Hypertension in diabetes: is there a place for age-adjusted centile cut-offs in those aged <50 years?

BACKGROUND: Conventional cut-offs for hypertension are arbitrary, and vascular complications can occur below these values, particularly in diabetes. AIM: To evaluate systolic blood pressure (SBP) distribution in diabetes and control populations, comparing hypertension prevalence using either conventional cut-offs (140 and 160 mmHg) or age-adjusted centile (75(th) and 90(th)) cut-offs derived from the control population. METHODS: We compared 2521 individuals with diabetes to 5809 controls, after excluding those on anti-hypertensives and with established vascular disease in both groups. RESULTS: Diabetic individuals were older (mean +/- SD 56 +/- 16 vs. 43 +/- 16years, diabetes vs. controls), and had higher BMI (29 +/- 5 vs. 24 +/- 4 kg /cm(2)) and SBP (145 +/- 23 vs. 131 +/- 18 mmHg, all p < 0.001). These factors were adjusted for in subsequent analysis. SBP rose with age and was also significantly higher in the diabetes group. In diabetes, conventional cut-offs indicated less hypertension in those aged < 50 years, compared to age-adjusted centile cut-offs. In age bands 18-29, 30-39, 40-49, 50-59, 60-69 and >70 years of the diabetes group, 24%, 33%, 43%, 62%, 70% and 74%, respectively exceeded 140 mmHg, compared to 35%, 44%, 43%, 45%, 40% and 27% exceeding the control-derived 75(th) centile value. DISCUSSION: The use of control-derived age-adjusted cut-offs may provide an alternative approach to define hypertension in diabetes that may be of particular relevance to younger patients, although this would require validation against outcomes.

Adolescent↗
PubMed2002

Alu DNA polymorphism in ACE gene is protective for age-related macular degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. We report an association between an Alu polymorphism in the angiotensin-converting enzyme (ACE) gene with the dry/atrophic form of AMD. Using the polymerase chain reaction (PCR) on genomic DNA isolated from patients with AMD (n=173), and an age-matched control population (n=189), we amplified a region polymorphic for an Alu element insertion in the ACE gene. The Alu(+/+) genotype occurred 4.5 times more frequently in the control population than the dry/atrophic AMD patient population, (p=0.004). The predominance of the Alu(+/+) genotype within the unaffected control group represents a protective insertion with respect to the human ocular disease, dry/atrophic AMD. This is the first demonstration of an Alu element insertion exerting protective effects against a known human disease.

Age Factors↗
PubMed1998

A review of the economics of the prevention and control of rabies. Part 2: Rabies in dogs, livestock and wildlife.

Although rabies in domestic and wild animals represents a significant threat to public health and can cause economic losses among livestock, there are very few studies that examine the economics of rabies in animals. The literature that does exist can be characterised as poorly documented estimates of costs, with insufficient information to allow replication of the analyses. Most papers have numerous 'violations' of the standard recommended procedures for assessing burden of disease and the cost and benefits of interventions. For example, most studies do not distinguish between financial charges and true economic costs. Further, despite the fact that controlling rabies in animal populations is often a multi-year task, only a few papers contain a multi-year framework, complete with discounting of future costs and benefits. Globally, dog-transmitted rabies represents the largest threat to human health. In order to prevent the transmission of rabies in a dog population, it is theoretically necessary to vaccinate a minimum of 60 to 70% of the dogs. Even countries with potentially sufficient resources, however, do not often meet and sustain these rates. One reason for such failure might be that individual dog owners might feel that it is too expensive to vaccinate their pets. Recent estimates in the US of the cost of vaccinating dogs range from $US16 to $US24 per dog. In developing countries, estimates range from $US0.52 in Thailand, to $US1.19 in the Philippines, to $US2.70 in Malawi. None of these estimates include indirect costs accured by the pet owners. Lethal methods of dog population control are even more expensive, and attempting to control rabies by reducing dog populations has not worked for any extended period. Rabies in livestock is often reported, but the impact in the US and most developed countries appears relatively small. Vampire bat-transmitted rabies in Latin America appears to be the most serious rabies problem in livestock. The largest cost due to wildlife rabies is the cost of vaccinating domestic animals, both large and small. In the US, domestic animals face multiple sources of wildlife rabies. Attributing the entire cost of vaccinating domestic animals to 1 species can result in the over estimation of the benefits of immunising a given wildlife population via vaccine-laden baits. For example, despite a definite decline in the number of rabid foxes, it has been difficult to obtain the promised benefits of using oral vaccines in Europe to control fox rabies. Other authors maintain that the use of oral vaccines to control fox rabies is cost beneficial, but there are no convincing data supporting that claim. Additionally, vaccinating raccoons with an oral vaccine requires approximately 4 times more vaccine-laden baits vaccinating foxes, which makes it highly questionable if it would be cost beneficial to use oral vaccine to attempt raccoon rabies elimination in areas where it is already enzootic. The economics of using oral vaccines to prevent raccoon rabies invading uninfected areas has yet to be examined.

Animal Diseases↗
PubMed1992

Siblings and parents of children with autism: a controlled population-based study.

The siblings and parents of 35 children with infantile autism/autistic disorder were compared with those of children with deficits in attention, motor control and perception (DAMP) and of normal children for reported speech and language problems, reading and spelling problems, social deficits and psychiatric disorders. Children with autism tended more often to be the first and only child and there was some support for genetic stoppage in this group. Learning disorders were equally common among siblings and parents of the autism and normal groups, but less common compared with the DAMP group. Asperger syndrome was more common among first-degree relatives of children with autism compared with normal children. There was a tendency for schizo-affective disorder to be more common among mothers of children with autism. The findings are discussed in the context of a genetic model for the development of autism.

Autistic Disorder↗
PubMed1996

Bucodental health condition in patients with Down syndrome of Cordoba City, Argentina.

The oral health condition of children and youngsters with Down Syndrome (DS) was evaluated on a sample of 86 mongolic subjects ages 3 to 19, both sexes, residents in the city of Córdoba (Argentina), and compared with control groups. Those persons were attended special educational institutions for the care of that type of disabled individuals. In every age group, the dmf-t and dmf-s indexes were higher in the mongolic children than in the control population, while from the age of 10 onwards the DMF-T and DMF-S of the control population were higher than those of the DS individuals. In spite of this, the scarce participation of the DF component in the mentally disabled showed deficiencies in their dental care. This population exhibited a high frequency of retarded eruption, agenesis, conoidism, Angle's type III malocclusion, posterior cross bite and deficient gingival health. A positive correlation was found between tha activity of Lactobacillus and the amount of Streptococcus and the caries indicators. A high concentration of calcium and secretory IgA was found in the group of mongolic subjects. Our analysis evidences that DS patients are at a disadvantage in relation with healthy individuals in terms of oral health. An early program of preventive measures is proposed (dental hygiene, anti-plaque agents, Therapy of Orofacial Regulation) which would involve the education of parents and teachers.

Adolescent↗
PubMed2006

Ethnic variation in AMD-associated complement factor H polymorphism p.Tyr402His.

Age-related macular degeneration (AMD) is the most common cause of irreversible visual loss in the developed world. Previous studies have demonstrated that the c.1204T>C, p.Tyr402His allelic variant in the complement factor H (CFH) gene is associated with an approximately three-fold increased risk for AMD in Caucasians of predominantly European descent. Both the prevalence as well as the phenotypic spectrum of AMD varies widely among persons of different ethnicities. We hypothesized that populations with a lower prevalence of AMD might also have a lower prevalence of the CFH risk allele. In this study we sought to determine the frequency of this sequence variant in control populations of Caucasians, African Americans, Hispanics, Somalis, and Japanese. Normal control populations were assembled for each ethnic group: Caucasian (n=148), Somali (n=128), African American (n=75), Hispanic (n=81), and Japanese (n=82). Individuals were genotyped using a restriction digest assay and the frequency of the C allele at nucleotide position 1204 of the CFH gene was determined. A bioinformatic approach was used to identify SNPs in linkage disequilibrium with rs1061170 (c.1204T>C, p.Tyr402His) from the human haplotype map project database (HapMap) in order to validate the findings. We found widely discordant frequencies of the risk allele between some of the different ethnic groups: Japanese 0.07+/-0.02, Hispanics 0.17+/-0.03, African-Americans 0.35+/-0.04, Caucasians 0.34+/-0.03, and Somalis 0.34+/-0.03. Allele frequencies generated by analysis of the HapMap database were consistent with these findings. This study suggests that there are other yet unidentified genetic factors important in the pathogenesis of AMD that may mitigate the effects of c.1204T>C, p.Tyr402His variant.

Aged↗
PubMed2002

Use of drugs, alcohol and tobacco by people with schizophrenia: case-control study.

BACKGROUND: Specialised services should be developed to help people with schizophrenia and associated substance misuse. The extent of the problem therefore needs to be known. AIMS: To determine the use of drugs, alcohol and tobacco by people with schizophrenia drawn from rural, suburban and urban settings, and to compare use by general population control subjects. METHOD: People with schizophrenia (n=316) and general population controls of similar gender distribution, age and postcode area of residence (n=250) were identified in rural, urban and suburban areas of Scotland. Use of drugs and alcohol was assessed by the Schedules for Clinical Assessment in Neuropsychiatry, and use of tobacco by a questionnaire. RESULTS: More patients than controls reported problem use of drugs in the past year (22 (7%) v. 5 (2%)) and at some time before then (50 (20%) v. 15 (6%)) and problem use of alcohol in the past year (42 (17%) v. 25 (10%)) but not at some time previously (99 (40%) v. 84 (34%)). More patients were current smokers (162 (65%) v. 99 (40%)). CONCLUSIONS: Problem use of drugs and alcohol by people with schizophrenia is greater than in the general population, but absolute numbers are small. Tobacco use is the greatest problem.

Adult↗
PubMed1995

[Eating disorders and metabolic balance in a population++ of young adults with insulin-dependent diabetes].

We have compared the prevalence of Eating Disorders in a population of 69 out-patients with Insulin-Dependent Diabetes Mellitus including a sample of diabetic young women (average year: 23 years) with two control populations (45 medicine out-patients and 54 girl students). The diabetic population didn't present no more eating disorders--measured by self-report questionnaires (EAT, BITE) than the control population. In a sample of 40 diabetic subjects--having participated in a diagnostic structured interview (LENTCA) based on DSM-III-R criteria: nobody has anorexia nervosa, one woman has bulimia nervosa, the lifetime prevalence of bulimia nervosa not otherwise specified was 21% for men and 43% for women. Bulimia Disorders--measured by self report questionnaire (BITE) and noncompliance were linked with poor glycemic control.

Adult↗
PubMed1996

Neuropathology of human sympathetic autonomic ganglia.

The neuropathologic alterations which underlie autonomic nervous system dysfunction in aging and in a variety of diseases have been systematically examined in the sympathetic ganglia of a series of 347 autopsied adults and in a review of previously published studies. Markedly swollen terminal axons containing neurofilamentous aggregates were found immediately adjacent to the neuronal cell bodies of prevertebral sympathetic ganglia in aging, in diabetes, and, to a lesser extent, in alcoholism. Dystrophic axons appeared to involve subpopulations of intraganglionic nerve fibers, chiefly those containing neuropeptide Y (NPY), and were more frequent in males than females. Neither aging nor diabetes resulted in significant numbers of actively degenerating neurons or a substantial decrease in neuronal density. Parenchymal aggregates of lymphocytes in the ganglionic neuropil and perivascular regions represented a frequent histologic finding in both prevertebral and paravertebral ganglia; however, they were not selectively increased in frequency or intensity in diabetic subjects or in any other disease entity. Many dilated clear "vacuoles," apparently located within the neuronal cell bodies of paravertebral and prevertebral ganglia according to light microscopy, were subsequently shown by electron microscopy to represent vacuolated or fluid-filled neurites, most likely terminal axons or synapses. Vacuolated neurites were more frequent in, although not confined to, diabetic patients. Similar pathologic findings have been reported in studies of sympathetic ganglia in various human diseases. The frequency of some pathologic lesions in control populations as a function of age or gender necessitates the careful selection of a relatively large, appropriately matched, control population for comparison with presumed disease-induced ganglionic neuropathology, and emphasizes the importance of quantitative comparisons.

Adolescent↗
PubMed2003

Effect of contact lens wear on central corneal thickness measurements.

PURPOSE: To compare central corneal thickness measurements as a function of contact lens wear in patients presenting for refractive surgery. SETTING: Gimbel Eye Centre, Saskatoon, Saskatchewan, Canada. METHODS: A retrospective study of charts yielded 634 eyes meeting the inclusion criterion. Pachymetry measurements of spectacle-wearing control eyes were compared to those of full-time soft contact lens wearers and rigid gas-permeable contact lens wearers. All measurements were taken with the DGH ultrasonic pachymeter by a single observer. RESULTS: Soft contact lens wearers had a mean reduction in corneal thickness measurements of 22 micrometers compared to the control population (P =.00001). Rigid gas-permeable lens wearers had a reduction of 24 micrometers compared to the control population (P =.00001). CONCLUSION: There was a clinically significant reduction in corneal thickness measurements associated with full-time contact lens wear.

Contact Lenses↗