Ignite Creation Date:
2024-05-05 @ 10:00 AM
Last Modification Date:
2024-10-26 @ 9:01 AM
Study NCT ID:
NCT00000128
Status:
UNKNOWN
Last Update Posted:
2005-06-24
First Post:
1999-09-23
Brief Title:
A Trial of Bifocals in Myopic Children With Esophoria
Sponsor:
National Eye Institute NEI
Organization:
National Eye Institute NEI
Study Overview
Official Title:
None
Status:
UNKNOWN
Status Verified Date:
2002-06
Last Known Status:
ACTIVE_NOT_RECRUITING
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
To test the hypothesis that correction with bifocal spectacle lenses rather than single-vision lenses will slow the progression of myopia in children with near-point esophoria The primary outcome variable is cycloplegic refraction as measured with an automated refractor Axial length is measured with ultrasound in order to test the corollary hypothesis that use of bifocals will slow ocular growth in these myopic children We will also examine the amount of close work performed by subjects and the degree of parental myopia as factors that may influence myopia progression
Detailed Description:
About 25 percent of all persons in the United States are myopic The most common form of myopia is childhood myopia which begins after age 6 and progresses rapidly until age 16 Myopia progression results from excessive growth of the eye primarily by enlargement of the vitreous chamber Excessive elongation of the eye is a major risk factor for retinal detachment
Previous prospective studies failed to show that use of bifocals was effective in slowing myopia progression However these studies did not separate subjects by near-point phoria before randomization Retrospective studies by David Goss indicated that bifocals slowed myopia progression by almost 50 percent in children with near-point esophoria but had no effect on children with exophoria
A small prospective pilot study completed by the investigators of this trial also supported the hypothesis that bifocals slow myopia progression in children with near-point esophoria Thirty-two myopic children all of whom showed near-point esophoria were enrolled in this 18-month study Twenty-eight children completed the study with 14 randomized into bifocals and 14 into single-vision lenses Cycloplegic automated refraction was performed every 6 months Over the course of the whole study there was a small statistically insignificant difference in the rates of myopia progression 057 diopters per year Dyr SE 011 for those in single-vision lenses compared with 036 Dyr SE 012 for those in bifocals p 026
However significant seasonal effects in myopia progression were demonstrated and the results also suggested that the beneficial effects of bifocals may take several months to develop During the first 6 months which included most of the school year myopia progression was rapid in both the bifocal group 061 Dyr and the single-vision group 068 Dyr During the second 6 months which included all of the summer vacation myopia progression was slow in both groups 032 and 026 Dyr for bifocal wearers and single-vision wearers respectively During the last 6 months ie the second school year myopia progressed slowly in the bifocal wearers 037 Dyr but rapidly 080 Dyr in single-vision wearers A repeated-measure analysis of variance demonstrated a significant seasonal effect p 0002 and a significant interaction between season and type of correction p 0043
The apparent effectiveness of bifocals in children with near-point esophoria and the lack of effectiveness in other children may be explained by a greater lag of accommodation in children with esophoria This lag might cause a slightly blurred retinal image that the bifocal may sharpen Other mechanisms might also be involved
Eighty or more myopic children all with near-point esophoria as measured at baseline with von Graefe prisms through a current myopic correction placed in a phoropter will be randomly assigned to wear either single-vision spectacle lenses or lenses with 150 D add in a flat-top 28-mm segment Subjects will visit one of two sites either a private optometry practice in Tulsa or the optometry clinic at Northeastern State University every 6 months Data collected at each visit will include automated refraction after cycloplegia with 1 percent tropicamide biometry with A-scan and estimates of the amount of study and other close work by means of questionnaires administered to the subjects and their parents We will also obtain measures of the degree of myopia in the biological parents The myopic correction will be changed if the spherical component of the refraction in either eye has changed by 05 diopter or more or if any change in cylinder power or axis improves vision in either eye by three letters or more The study will continue for 30 months and will include six visits by each subject
Previous prospective studies failed to show that use of bifocals was effective in slowing myopia progression However these studies did not separate subjects by near-point phoria before randomization Retrospective studies by David Goss indicated that bifocals slowed myopia progression by almost 50 percent in children with near-point esophoria but had no effect on children with exophoria
A small prospective pilot study completed by the investigators of this trial also supported the hypothesis that bifocals slow myopia progression in children with near-point esophoria Thirty-two myopic children all of whom showed near-point esophoria were enrolled in this 18-month study Twenty-eight children completed the study with 14 randomized into bifocals and 14 into single-vision lenses Cycloplegic automated refraction was performed every 6 months Over the course of the whole study there was a small statistically insignificant difference in the rates of myopia progression 057 diopters per year Dyr SE 011 for those in single-vision lenses compared with 036 Dyr SE 012 for those in bifocals p 026
However significant seasonal effects in myopia progression were demonstrated and the results also suggested that the beneficial effects of bifocals may take several months to develop During the first 6 months which included most of the school year myopia progression was rapid in both the bifocal group 061 Dyr and the single-vision group 068 Dyr During the second 6 months which included all of the summer vacation myopia progression was slow in both groups 032 and 026 Dyr for bifocal wearers and single-vision wearers respectively During the last 6 months ie the second school year myopia progressed slowly in the bifocal wearers 037 Dyr but rapidly 080 Dyr in single-vision wearers A repeated-measure analysis of variance demonstrated a significant seasonal effect p 0002 and a significant interaction between season and type of correction p 0043
The apparent effectiveness of bifocals in children with near-point esophoria and the lack of effectiveness in other children may be explained by a greater lag of accommodation in children with esophoria This lag might cause a slightly blurred retinal image that the bifocal may sharpen Other mechanisms might also be involved
Eighty or more myopic children all with near-point esophoria as measured at baseline with von Graefe prisms through a current myopic correction placed in a phoropter will be randomly assigned to wear either single-vision spectacle lenses or lenses with 150 D add in a flat-top 28-mm segment Subjects will visit one of two sites either a private optometry practice in Tulsa or the optometry clinic at Northeastern State University every 6 months Data collected at each visit will include automated refraction after cycloplegia with 1 percent tropicamide biometry with A-scan and estimates of the amount of study and other close work by means of questionnaires administered to the subjects and their parents We will also obtain measures of the degree of myopia in the biological parents The myopic correction will be changed if the spherical component of the refraction in either eye has changed by 05 diopter or more or if any change in cylinder power or axis improves vision in either eye by three letters or more The study will continue for 30 months and will include six visits by each subject
Study Oversight
Has Oversight DMC:
None
Is a FDA Regulated Drug?:
None
Is a FDA Regulated Device?:
None
Is an Unapproved Device?:
None
Is a PPSD?:
None
Is a US Export?:
None
Is an FDA AA801 Violation?:
None