Biomedical subjects

C Enger

Publications and source records attributed to C Enger.

At least 73 records · Page 4Linked to original sources

PubMed1991

The effect of age and initial visual acuity on the systemic and visual prognosis of central retinal vein occlusion.

Papillophlebitis is the term that is often used to describe a central retinal vein occlusion with preserved visual acuity in a young, healthy patient. Among 194 patients with a diagnosis of central retinal vein occlusion (CRVO), 19 patients were identified who were under 50 years of age and who had visual acuity of 6/12 or better in the affected eye. These patients retained good vision in the affected eye during the course of the disorder with 17 eyes returning to 6/6. All of these patients remained healthy over a mean follow-up period of about four years. This group of patients was compared to a second group of 28 patients who also were under 50 years of age, but who had initial visual acuity in the affected eye less than 6/12. These patients had a variable visual outcome. In addition, they had a higher prevalence of systemic hypertension over the follow-up period than did a group of age-matched control subjects. An additional comparison was made to a group of 26 patients with visual acuity of 6/12 or better in the affected eye but who were over 50 years of age. Forty-six per cent of these patients had final visual acuity less than 6/12, and they had a higher prevalence of systemic vascular disease than did a group of age-matched control subjects.

Adult↗

PubMed1991

Murine models of Sjögren's syndrome. Evolution of the lacrimal gland inflammatory lesions.

Lacrimal gland inflammation develops in a number of autoimmune mice, including the MRL/Mp-lpr/lpr (MRL/lpr), MRL/Mp(-)+/+ (MRL/+), and NZB x NZW F1 hybrid (NZB/W) strains. The authors studied the evolution of this process, MRL/lpr mice had inflammatory lesions at 4 weeks old. The lesions had enlarged by 2 months and were fully developed by 4 to 5 months of age. In MRL/+ mice, 4-week-old mice had no lesions, although some focal inflammation was detectable at 3 months old. Significant abnormalities were present at 6 months, and persisted and increased throughout life, with all mice having extensive lesions at 18 months or older. In NZB/W mice, the authors detected no lesions until 6 months of age, and these lesions were fully developed in 9 months. Immunocytochemical profiles, of the cell types infiltrating the lacrimal gland, showed differences not only between the strains, but also in each strain as inflammation progressed. All three types of mice had L3T4+ T cells as the major lymphocyte component, although MRL/+ had significantly more Lyt 2+ T cells than the other strains. NZB/W mice had significantly more B cells than the two MRL substrains. In both NZB/W and MRL/+ mice, there was a significant increase in the B cell population, and a decrease in the percentage of L3T4+ T cells. There was a significant decline in Lyt 2+ T suppressor/cytotoxic cells in both NZB/W and MRL/lpr mice. This last finding was consistent with the more rapid development of inflammation in these strains than in the MRL/+ mice, where Lyt 2+ T suppressor/cytotoxic cells persist. Together, these results indicate that the autoimmune response in murine models of Sjögren's syndrome is a dynamic, evolving process with strain-related changes in lymphocyte subsets.

Animals↗

PubMed1990

Visual impairment in a rural Appalachian community. Prevalence and causes.

A population-based survey of 1136 subjects aged 40 years and older was conducted in a rural valley of Kentucky to determine the nature and extent of visual disability in an underserved area of rural America. Data on corrected visual acuity and ocular history, along with demographic, socioeconomic, and health care utilization parameters, were gathered. Those subjects with an acuity below 20/60 in either eye underwent a comprehensive ophthalmologic examination. The prevalence of binocular blindness (acuity worse than 20/400 in the better eye) was 0.44% and of monocular blindness (acuity worse than 20/400 in one eye) was 3.3%, approximately twice the national rates. The chief cause of bilateral visual impairment was macular degeneration among men and cataract among women. Cataract, trauma, and amblyopia were the major causes of monocular visual impairment in both sexes. Risk factor analysis revealed younger age, higher education, active employment, access to a health care facility, and comprehensive health insurance coverage to be inversely associated with visual impairment.

Adult↗

PubMed1990

The natural course of central retinal vein occlusion.

We reviewed the records of 160 patients who had central retinal vein occlusion between 1980 and 1985. Of 168 eyes, 107 (64%) were classified as nonischemic types and 61 (36%) were classified as ischemic types. Of 107 nonischemic eyes, ten (9%) converted to the ischemic variant. Of 107 nonischemic eyes, 33 (31%) lost three or more lines of visual acuity irrespective of initial visual acuity. A final visual acuity less than or equal to 20/200 was recorded in 57 of 61 (93%) of ischemic eyes and 53 of 107 (50%) of nonischemic eyes.

Adolescent↗

PubMed1990

The relationship of puberty to diabetic retinopathy.

The presence of background and preproliferative retinopathy in 70 patients with type I diabetes was correlated with their pubertal development. Pubertal status was assessed by pediatricians using the sexual maturity ratings of Tanner. In young diabetics with comparable disease duration (5 to 10 years), postpubertal children had a greater prevalence of retinopathy than those who were not sexually mature. After adjusting for duration of diabetes and sex, the relative odds of having retinopathy in the postpubescent group relative to the prepubescent or pubescent groups was 4.8 (95% confidence interval: 1.5 to 15.3). This study suggests that minimal retinopathy in children is not rare and that postpubescent children have a greater prevalence of diabetic retinopathy than do prepubescent children with similar diabetes duration.

Adolescent↗

PubMed1990

Quantitative regional structure of the normal human lamina cribrosa. A racial comparison.

We digitized magnified photographs of cross-sections of the laminae cribrosae of 16 normal subjects 50 or more years of age. The sample included 7 blacks and 9 age-matched whites. Connective tissue area as a proportion of the lamina cribrosa area was significantly less and pores were significantly larger in the superior and inferior than in the nasal and temporal quadrants of the lamina cribrosa. These differences were more pronounced for peripheral as compared with central regions of the lamina cribrosa. Less connective tissue support for nerve fibers in the superior and inferior quadrants of the optic nerve head could contribute to their greater susceptibility to glaucoma damage by allowing greater distortion of these regions at elevated intraocular pressures. The least connective tissue support was present in the inferoperipheral region of the lamina cribrosa, which may be related to the greater frequency of superior visual field defects in glaucoma. Blacks had larger total lamina cribrosa area, indicating a larger optic nerve head, and also a greater number of laminar pores than whites. However, the connective tissue proportion and pore size distribution in the laminae cribrosae of blacks were almost identical to those of whites. We found no evidence suggesting that the greater susceptibility of blacks to glaucoma damage is due to less connective tissue support for nerve fibers passing through their laminae cribrosae than in whites.

Aged↗

PubMed1990

Cardiovascular and intraocular pressure effects and plasma concentrations of apraclonidine.

We performed a double-masked, crossover study comparing the cardiovascular and intraocular pressure effects of 0.5% and 0.25% topical apraclonidine hydrochloride and 0.5% timolol maleate in 20 healthy female volunteers. The contralateral effects of unilateral apraclonidine and the plasma concentrations of apraclonidine were also assessed. All measurements were done 2, 5, and 8 hours after drop instillation. A 15-minute treadmill test was performed after the 2-hour measurements. All three active medications lowered intraocular pressure comparably. There was no significant contralateral intraocular pressure effect seen with apraclonidine. The apraclonidine plasma concentrations were variable and unrelated to the amount of intraocular pressure lowering and cardiovascular parameters measured. Apraclonidine did not affect blood pressure or heart rate any differently than placebo. Timolol, however, blunted exercise-induced tachycardia. There were no significant differences in pupillary diameters or interpalpebral fissure widths among treatment groups.

Administration, Topical↗

PubMed1990

The risk for systemic vascular diseases and mortality in patients with central retinal vein occlusion.

In this cross-sectional study, the authors evaluated 197 patients diagnosed with central retinal vein occlusion (CRVO) at the Wilmer Ophthalmological Institute between 1980 and 1985 to determine the risk of systemic disease and mortality. Complete follow-up information for mortality was obtained in 191 (97%). National Health Interview Survey (NHIS) patients and Wilmer cataract patients formed two comparison groups. The prevalence of hypertension was significantly elevated in the CRVO cases when compared with both comparison groups (P less than 0.03, 0.005). The prevalence of diabetes mellitus was increased in CRVO cases in comparison with the NHIS group (P less than 0.005). The prevalence of cerebrovascular or cardiovascular disease was the same for all three groups, as was overall mortality. Mortality was not increased in CRVO cases as compared with United States mortality rates.

Adolescent↗

PubMed1990

Changing indications for cataract surgery: 1974 to 1988.

To examine changes in indications for cataract surgery which have contributed to the increasing rate of cataract extractions, we compared preoperative characteristics of 265 patients who had undergone surgery in 1988 with a similar number who had undergone surgery by the same four ophthalmologists in 1974 and 1982. Between 1974 and 1988 the number of extractions performed annually by two high-referral hospital-based surgeons rose by 68%. Over 90% of these procedures in 1974 were intracapsular extractions; in 1988, 90% were extracapsular extractions with intraocular lenses. In 1988, preoperative visual acuity was better in both the study eyes and the fellow eyes, the proportion of those with acuities better than 20/60 having risen from 10% to 21%, and from 49% to 67%, respectively. The proportion of patients waiting more than 2 years for surgery on the second eye doubled between 1974 and 1988. These changes, already evident by 1982 for the hospital-based surgeons, became characteristic of the community-based surgeons' practices as well between 1982 and 1988.

Adult↗

PubMed1989

Cytomegalovirus retinitis and acquired immunodeficiency syndrome.

In a series of 157 patients with acquired immunodeficiency syndrome (AIDS), 46 (29%) developed cytomegalovirus (CMV) retinitis. In five patients, CMV retinitis was the initial AIDS-defining opportunistic infection (11% of patients with CMV retinitis and 3% of patients with AIDS). Retinal detachments developed in seven patients (15%) and in four were present before the institution of ganciclovir therapy. Bilateral CMV retinitis was present in 35% of patients at presentation and subsequently developed in nine (60%) of 15 patients while not being treated with ganciclovir. Conversely, none of 18 patients with unilateral disease developed bilateral disease while receiving ganciclovir. Of patients treated with ganciclovir for their CMV retinitis, 81% had a response to the drug, and 61% achieved a complete response, resulting in a nonprogressive and inactive scar. Patients who achieved a complete response with ganciclovir had a significantly longer survival than those who did not, suggesting greater immune compromise in those patients who failed to respond to ganciclovir.

Acquired Immunodeficiency Syndrome↗

PubMed1989

The cup-to-disc ratio and central retinal vein occlusion.

Recent reports have suggested that a small optic cup may contribute to the development of certain optic disc disorders, such as anterior ischemic optic neuropathy. In a masked fashion, the cup-to-disc ratios from the fellow eyes of 55 patients with central retinal vein occlusion (CRVO) were compared with 55 controls to determine whether a similar association could be established for CRVO. Controls came from two population-based surveys, and they were matched to cases for age, race, and sex. The mean cup-to-disc ratios for the CRVO fellow eyes and controls were 0.39 and 0.40, respectively; the distribution of the sizes of the cup-to-disc ratios was nearly identical in the two groups. These results suggested that the cup-to-disc ratio is not a useful predictor of the development of CRVO.

Female↗

PubMed1989

Refractive changes after scleral buckling surgery.

Pneumatic retinopexy is increasingly recommended to treat some patients with retinal detachment to avoid the complication of induced refractive changes sometimes associated with scleral buckling procedures. Prospective evaluation of refractive changes after scleral buckling procedures was performed in 75 eyes of 69 patients. Encircling scleral buckles caused an average increased axial length of 0.99 mm and average induced myopia of 2.75 diopters. Induced astigmatism was likely to occur in patients undergoing scleral buckling surgery, but it was not related to whether a radial element was used.

Adolescent↗

PubMed1989

Extraocular muscle imbalance after scleral buckling surgery.

Pneumatic retinopexy is advocated to treat some retinal detachment cases, in part to avoid the complication of induced strabismus sometimes associated with scleral buckling procedures (SBPs). Prospective evaluation of postoperative muscle imbalance was performed in 76 eyes of 69 patients undergoing SBP. Measureable limitation of ductions occurred in 40 (73%) of the 55 eyes for which a full set of duction measurements could be obtained. Among 53 patients without previous retinal surgery in either eye, postoperative deviations were associated with encircling scleral buckles (P = 0.00003), but not with radial scleral buckles (P = 0.6). Significant strabismus occurred in 12 patients (23%), and three required surgery or prism therapy. Candidates for pneumatic retinopexy can usually be treated by a radial scleral buckling procedure, and therefore the risk of postoperative strabismus is low if this technique is selected.

Adolescent↗

PubMed1989

Specular microscopy of hard contact lens wearers II.

Specular microscopy was done on 65 long-term hard contact lens (CL) wearers and controls matched for age, sex, race, and refractive error. There was no difference in mean endothelial cell size between the two groups, although median cell area was slightly smaller in the CL group. Standard deviation and coefficient of variation increased as the duration of total wearing time increased and were greater in the CL group, as was skewness. In 15 long-term hard CL wearers who had discontinued their CL wear, there was a trend towards persistence of pleomorphism and polymegathism of cells compared with non-contact lens (NCL) wearers, but there was a suggestion of recovery compared with those continuing to wear CLs matched for duration of wear.

Adult↗

PubMed1989

Idiopathic epiretinal membranes. Ultrastructural characteristics and clinicopathologic correlation.

Current theories of idiopathic epiretinal membrane (ERM) pathogenesis, based mainly on clinical and autopsy studies, emphasize a glial tissue origin. The clinical and ultrastructural features of 101 cases of idiopathic ERMs removed from the macular area during vitrectomy were studied. The predominant cell type was retinal pigment epithelium (RPE) in 51 cases, fibrous astrocytes in 29 cases, fibrocytes in 14 cases, and myofibroblasts in 7 cases. Features of myofibroblastic differentiation were present in 64 cases. Myofibrocytes were more common in younger patients with shorter duration of symptoms. Fibrous astrocytes were more common in females. The high incidence of RPE cells in this series raises new questions regarding the pathogenesis of idiopathic ERMs.

Adolescent↗

PubMed1989

Correlation of fibrosis and transforming growth factor-beta type 2 levels in the eye.

Approximately 1 out of every 10 eyes undergoing surgery for retinal detachment develops excessive intraocular fibrosis that can lead to traction retinal detachment and ultimate blindness. This disease process has been termed proliferative vitreoretinopathy (PVR). The ability to monitor and grade this fibrotic response accurately within the eye as well as the ability to aspirate vitreous cavity fluid bathing the fibrotic tissue makes this an ideal setting in which to investigate the development of fibrosis. Although laboratory studies have recently shown that transforming growth factor-beta (TGF-beta) can enhance fibrosis, little clinical evidence is yet available correlating the level of this or other growth factors with the degree of fibrosis in a clinical setting. We have found that vitreous aspirates from eyes with intraocular fibrosis associated with PVR have more than three times the amount of TGF-beta (1,200 +/- 300 pM [SEM]) found in eyes with uncomplicated retinal detachments without intraocular fibrosis (360 +/- 91 pM [SEM]). Using an in vitro assay, 84-100% of the TGF-beta activity could be blocked with specific antibodies against TGF-beta 2, whereas only 10-21% could be blocked by specific antibodies against TGF-beta 1. TGF-beta 1 was used in an animal model of traction retinal detachment. Since beta 1 and beta 2 have essentially identical biologic effects and only human beta 1 was available in quantities required, beta 1 was chosen for these in vivo studies. The injection of TGF-beta1 plus fibronectin (FN) but not TGF-beta1 alone into the vitreous cavity of rabbits resulted in the increased formation of intraocular fibrosis and traction retinal detachments as compared to control eyes. In previous studies, intravitreal FN levels were also found to be elevated in eyes with intraocular fibrosis.

Adolescent↗

PubMed1989

Quantitative analysis of wide-field specular microscopy. II. Precision of sampling from the central corneal endothelium.

The precision of the measurement of mean endothelial cell area obtained by sampling with small-field and wide-field specular microscopy from the central 4 mm of human corneal endothelium was studied by comparing endothelial cell parameters from individual specular micrographs in vivo to the results obtained by montaging the micrographs from the entire central 4 mm of the same corneas. The small samples were at least 10% from the true mean cell size of all cells of the central 4 mm in any endothelium other than that with the most homogeneous pattern. A new algorithm for sampling with these two specular microscopes will need to be derived to permit a more precise measure of the mean area of endothelial cells in the central 4 mm of the human corneal endothelium.

Cell Count↗

PubMed1988

Nuclear sclerosis after vitrectomy for idiopathic epiretinal membranes.

We performed a retrospective analysis of lens changes occurring after vitrectomy for idiopathic epiretinal membranes causing macular pucker on 75 consecutive phakic eyes. Thirty-five eyes (47%) had appearance or progression of nuclear sclerosis. There were no changes in anterior subcapsular cataracts and three eyes (4%) had minimal changes in posterior subcapsular cataracts. Based on univariate analysis, presence of preoperative nuclear sclerosis, length of follow-up period, and surgeon were found to be associated with the occurrence or progression of nuclear sclerosis. Differences between surgeons were largely accounted for by the difference in proportions with preoperative nuclear sclerosis, and differing lengths of follow-up. Kaplan-Meier life table analysis performed on 53 eyes with examination of fellow eyes and longer follow-up showed significantly more nuclear sclerosis in the operated on eye when compared to the fellow eye (log-rank test, P less than .0001).

Actuarial Analysis↗