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Biomedical subjects

G W Fulk

Publications and source records attributed to G W Fulk.

14 recordsLinked to original sources
PubMed2000

A randomized trial of the effect of single-vision vs. bifocal lenses on myopia progression in children with esophoria.

BACKGROUND: Bifocals have long been thought to reduce progression of childhood myopia. However, this hypothesis has not been definitively evaluated. METHODS: We conducted a randomized clinical trial to test the hypothesis that bifocals slow myopia progression in children with near-point esophoria. Eighty-two myopic children were randomized to single-vision glasses (n = 40) or to bifocals with a +1.50 D add (n = 42) and were followed for 30 months. Refraction was measured by an automated refractor after cycloplegia. The primary outcome was myopia progression defined as the difference between the spherical equivalent at baseline and at the 30-month examination, averaged over both eyes. RESULTS: Follow-up was incomplete for six children in the bifocal group and one child in the single-vision group. Among the children completing the 30 months of follow up, myopia progression (mean spherical equivalent of the two eyes) averaged 0.99 D for bifocals and 1.24 D for single vision (unadjusted, p = 0.106; adjusted for age, p = 0.046). Treatment groups differed in their cumulative distributions (Kolmogorov-Smirnov procedure, p = 0.031). Evidence for a treatment effect on growth in vitreous chamber depth was similar (p = 0.046 by K.S.). CONCLUSION: Use of bifocals, instead of single-vision glasses, by children with near-point esophoria seemed to slow myopia progression to a slight degree.

Aging↗
PubMed1998

Baseline characteristics in the Myopia Progression Study, a clinical trial of bifocals to slow myopia progression.

BACKGROUND: Retrospective studies have indicated that myopic children with nearpoint esophoria experienced slower myopia progression if they wore bifocal glasses rather than single-vision glasses. A small, 18-month clinical trial also supported that finding, but the results were not statistically significant. The Myopia Progression Study was funded by the National Eye Institute to test more rigorously the efficacy of bifocals, compared with single-vision glasses, in slowing myopia progression in children with nearpoint esophoria. A secondary objective of the study was to identify other variables that might influence the rate of myopia progression. This report describes the design and methods of the Myopia Progression Study and the baseline characteristics of the subjects. METHODS: A 3-year, randomized clinical trial was initiated. Subjects were children between 6 and 12 years of age who were myopic (at least -0.50 D in each eye) and who demonstrated nearpoint esophoria by the von Graefe technique. RESULTS: Eighty-two children were enrolled. After blocking by gender and clinical site (two sites), subjects were randomly assigned to one of the two treatments: correction with single-vision spectacle lenses or correction with bifocal lenses having a +1.50 D add in a flattop segment. The average degree of myopia at baseline was -2.31 D (SD = 1.31 D). CONCLUSION: This clinical trial can be expected to determine the effectiveness of bifocal glasses in slowing the progression of myopia in children with nearpoint esophoria.

Child↗
PubMed1997

Endotoxin concentration in contact lens storage cases.

BACKGROUND: The contamination of contact lens storage cases by gram-negative bacteria has been associated with ulcerative keratitis. This study investigated the concentration of endotoxin, a substance produced by gram-negative bacteria, in contact lens cases. METHODS: The limulus amebocyte lysate (LAL) test was used to measure the concentration of endotoxin in the storage cases of 27 contact lens wearers. The units of concentration used were endotoxin units per ml (EU/ml). The type of storage solution used by each patient, as well as other aspects of lens care and use, were recorded. RESULTS: Twenty-one storage cases--78% of those tested--contained measurable amounts of toxin. Two cases contained extremely high concentrations of endotoxin: 60 EU/ml and 300 EU/ml. Both cases were from persons using Opti-Free. Cases from six persons using Opti-Free accounted for five of the top seven endotoxin concentrations when cases were ranked on that basis. Fewer hours of daily lens wear and lower lens age were also possibly associated with higher concentrations of endotoxin, although those associations may have resulted by chance (p = 0.057 and p = 0.095, respectively). CONCLUSIONS: The LAL test was useful in estimating the degree of contamination of cases by gram-negative bacteria. Most cases contained measurable amounts of endotoxin, indicating at least some contamination by gram-negative bacteria. The effectivity of Opti-Free in inhibition of bacterial growth in contact lens cases should be investigated further.

Biofilms↗
PubMed1996

Pilocarpine gel for the treatment of demodicosis--a case series.

BACKGROUND: Excessive numbers of the mite, Demodax folliculorum, in the eyelash follicies cause itching and is referred to as demodicosis. We evaluated 4% pilocarpine gel as a treatment for this condition. METHODS: An advertisement was placed in a retirement home newsletter, requesting persons with ocular discomfort. Respondents were examined for Demodex and persons with abundant mites were invited to participate. One eye was treated with pilocarpine gel; the other eye was untreated. The relative abundance of mites was evaluated at baseline, after 1 and 2 weeks of treatment. Subjects kept a daily log of symptoms. RESULTS: Eleven of 22 persons with ocular itching had abundant Demodax. Mites were reduced significantly by the treatment (p = 0.017). The amount of mite reduction was closely correlated with the extent to which itching was alleviated (r = 0.811, p = 0.008). CONCLUSION: Abundant Demodex is an important cause of ocular itching in older persons. Mites can be reduced with pilocarpine gel and itching alleviated.

Administration, Topical↗
PubMed1996

A comparison of three subjective tests for astigmatism and their interexaminer reliabilities.

BACKGROUND: Astigmatism is a common cause of blurred vision and asthenopia. Several different tests for the measurement of astigmatism have been described in the literature, but there are few studies that have compared the results of various tests. METHODS: The results of three astigmatism tests performed on 40 subjects by two examiners were compared. Two of the tests, the Jackson cross cylinder (JCC) and the Humphriss immediate contrast (HIC), utilized distance targets; one test, the Pratt test, involved a near target. RESULTS: The mean differences between all tests were less than 0.25D. There was a slight tendency for higher cylinder power to be found on the Pratt test. The three tests agreed within +/- 0.25D on cylinder power 80 to 98 percent of the time and within 10 degrees of cylinder axis 85 to 98 percent of the time. Interexaminer reliability showed mean differences less than 0.12D for each of the three tests, agreement within +/- 0.25D on cylinder power 88 to 90 percent of the time and within 10 degrees on cylinder axis 85 to 93 percent of the time. CONCLUSIONS: The results suggested that any of the three techniques could be substituted for another for astigmatism testing. On theoretical grounds, a binocular refraction method for cylinder axis determination, such as the HIC, is advisable for patients with cyclophorias and significant amounts of astigmatism. The results showed good reliability for each of the three methods.

Adolescent↗
PubMed1996

Can bifocals slow myopia progression?

BACKGROUND: Retrospective studies have suggested that in children with near point esophoria, bifocals can slow myopia progression by about 50 percent. A prospective study was conducted to test this hypothesis. METHODS: Thirty-two children, all with near point esophoria, were randomly divided into either correction with single-vision or with bifocal lenses containing a +1.25 D and. Axial length and refraction were measured under cycloplegia every 6 months for 18 months. Twenty-eight children completed the study. RESULTS: Myopia progressed at an equal rate in both groups for the first 12 months. Progression was much faster during the first 6 months, which was during the school year, than during the second 6 months, which included all of the summer vacation (0.64 D/yr vs 0.29 D/yr). During the last 6 months, myopia progressed rapidly for children in single-vision lenses (0.80 D/yr) but slowly for those in bifocals (0.37 D/yr). A repeated-measure analysis of variance showed that season of the year had a significant effect on myopia progression (p > 0.002) and that the effect differed for the two treatment groups (p > 0.043). Over the whole 18-month study, myopia progressed at rate of 0.57 D/yr for those in single-vision lenses and 0.39 D/yr in those in bifocals (p = 0.26). CONCLUSIONS: Bifocals seemed to slow myopia progression in these children with near-point esophoria, although a longer-term study with more subjects is needed to confirm this finding. Myopia progressed more rapidly during the school year than during summer vacation.

Adolescent↗
PubMed1992

Optic nerve crescents and refractive error.

In this paper we discuss whether the presence of an optic nerve crescent might affect the way in which axial length and corneal curvature interact to determine refractive error. Subjective refraction, keratometry, measurement of body height, axial length of the eye, and stereophotography of the optic nerves were performed on 224 subjects, 8- to 25-years-old. Photographs were examined under magnification; optic nerve crescents, if present, were measured in the horizontal dimension. Those measurements were then corrected for magnification due to the eye and the camera. Logistic regression analysis suggested that male gender and myopic refractive error were most directly associated with the presence of a large crescent, whereas axial length, age, and horizontal keratometry reading were less directly associated with the presence of a crescent. The relation between axial length and refractive error differed among those with large crescents compared to those with small or no crescents. Simple regression showed that, for those with a crescent at least 0.2-mm wide, a 1-mm greater axial length was associated with, on the average, 1.26 D of myopia. For those with smaller or no crescents, a 1-mm greater axial length was associated with only 0.66 D of myopia. This difference was statistically significant at the 0.02 level of confidence.

Adolescent↗
PubMed1991

Effect of simulated altitude on the visual fields of glaucoma patients and the elderly.

We investigated whether mild hypoxia, such as may be encountered in civilian aircraft, causes temporary visual field defects in elderly persons or temporarily increases pre-existing defects in persons with glaucoma. The central 24-2 program on the Humphrey automated perimeter was used to test visual fields in 3 groups of subjects: 6 with glaucoma; 12 age-matched controls, all of whom were over 44 years of age; and 6 normal subjects under 36 years of age. Visual fields were tested at ground level and at simulated 3000 m (10,000 ft) in an alternating sequence. A repeated measures design of multiple analysis of variance was used to analyze the data. Altitude was found to have no effect on the visual fields of subjects with glaucoma, age-matched normals, or younger subjects. We found no evidence to suggest a change in the present Federal Aviation Administration (FAA) standards, which allow a special certificate to be issued to persons with glaucoma who wish to obtain medical clearance to operate civilian aircraft, nor have we found any evidence that should discourage glaucoma patients from flying as passengers.

Adult↗
PubMed1991

Sympathetic denervation of the iris dilator in noninsulin-dependent diabetes.

Twenty-three subjects with noninsulin-dependent diabetes mellitus (NIDDM) and 23 age- and sex-matched controls were tested for sympathetic denervation of the iris dilator by comparing the mydriatic effect of the combination of 1% phenylephrine and 1% tropicamide with that of 1% tropicamide alone. Most of the diabetic subjects had no clinical signs of severe diabetic complications. Nine diabetics and two controls showed sympathetic denervation, defined as a 1 mm or greater dilation due the addition of 1% phenylephrine. One of those two controls had a recent history of vascular headache. The diabetics with pupillary neuropathy had higher glycosylated hemoglobin percentages and a history of higher fasting blood sugars (FBS's) than the diabetics with normal pupils. Our results show that pupillary neuropathy can develop in persons with diabetes, often before the other complications of diabetes become manifest.

Adult↗
PubMed1990

Association of diabetes, lash loss, and Staphylococcus aureus with infestation of eyelids by Demodex folliculorum (Acari: Demodicidae).

Six eyelashes, three from the upper lid and three from the lower lid, were epilated from 256 subjects and examined for Demodex. D. folliculorum (Simon) was found in 16% of the subjects. Mites were more abundant in older persons and in persons with diabetes. Mites also were associated with a scarcity of lashes in the lower lid. Hierarchical log-linear analysis showed that the associations of greater mite abundance with diabetes and with madarosis were independent of age. The 43 persons from whose lid margins Staphylococcus aureus was cultured seemed to have been more likely to have two or more mites than those without S. aureus (11.6 versus 5.2%), although this difference fell short of statistical significance (P = 0.125).

Adolescent↗
PubMed1990

A case report of demodicosis.

We report on a patient who had an excessive number of mites (Demodex folliculorum) on his eye lashes, i.e. 10 mites on eight lashes examined. A review of three previous reports suggested that one mite for every two lashes represents an over population of this nearly ubiquitous mite. Greasy scales on the lashes and foamy tears suggested that seborrhea was present as well as demodicosis. The primary symptoms of itching was relieved after one week of treatment with mercuric oxide ointment and lid scrubs, although the number of mites was not reduced. Treatment for an additional two weeks did reduce the mite number. We therefore recommend continuing treatment for demodicosis for at least three weeks even if symptoms abate sooner.

Aged↗
PubMed1988

Physiological variables affecting intraocular pressure in a population study.

Intraocular pressure (IOP) and several other parameters were measured on 560 subjects as part of a vision and health screening program. The sample included a large proportion of American Indians with diabetes (15.2%) and obesity. Multiple regression analysis showed that the percentage of ideal body weight index and average blood pressure both had independent effects on IOP, whereas age, blood sugar, sex, degree of Indian blood, and diabetes did not, although the latter three variables narrowly missed having a statistically significant effect in at least one eye. The analysis of variance showed that diabetes was associated with elevated IOP. This association was independent of random blood sugar, blood pressure, obesity index, and age.

Adolescent↗
PubMed1986

How to photograph and evaluate the retinal nerve fiber layer.

Defects in the retinal nerve fiber layer (RNFL), as revealed by black and white photography with short wave length light, are frequently an early sign of glaucoma. We describe how to photograph and evaluate the RNFL. Negatives can be mounted as slides with slide mounts and examined with a slit lamp. This eliminates costly printing and enlarging.

Glaucoma↗