The Contact Lens and Myopia Progression (CLAMP) Study

2014-07-24 14:35:11 | BioPortfolio


To examine the effects of rigid gas permeable contact lenses on the progression of myopia (nearsightedness) in children

To determine what changes in the eyes cause certain eyes to progress in nearsightedness more slowly


Rigid gas permeable (RGP) contact lenses provide clear, comfortable vision with relatively few ocular health risks and are a standard management option for correcting nearsightedness. While RGP contact lenses are used to correct myopic refractive error, they may also slow the progression of myopia. A definitive study that could provide guidance regarding the effects of rigid gas permeable contact lenses on myopia (nearsightedness) progression may define the standard of care for slowing the progression of myopia in young children.

An eye care practitioner first reported that hard contact lenses may slow or stop the progression of nearsightedness in 1956. Other anecdotal clinical reports with similar results soon followed. Previous review papers have suggested that rigid contact lenses slow the progression of myopia in children, and several studies have attempted to prove this.

Two studies in the past twenty years have shown that rigid gas permeable contact lenses slow the progression of nearsightedness in children, however both studies failed to provide proper attention to many important variables. While these earlier works produced intriguing results for scientists and clinicians, they contain many problems that challenge the significance of the studies findings. The faults of the previous studies can be summarized in four categories: 1) high losses to follow-up, 2) inadequate control group, 3) incomplete ocular component measurements, and 4) inadequate or poorly selected entry criteria.

Positive results in previous studies also failed to exclude alternate possibilities which may explain why rigid gas permeable contact lenses may slow the progression of myopia. For example, the studies found that rigid contact lenses slow the progression of myopia and that corneal flattening accounts for some of the treatment effect, but none of the studies was able to definitively answer other mechanisms that may slow myopia advancement. A need for a controlled study of rigid contact lenses which measures all of the components that may affect myopia progression still exists. The CLAMP Study examines all of these components and addresses the problems encountered in previous studies.

The CLAMP Study uses a run-in period to enroll only children who are able to adapt to rigid contact lens wear into the study. This decreases the number of children who drop-out of the study because they cannot adapt to rigid contact lens wear. Once children show that they are able to wear rigid contact lenses, they are enrolled in the study and randomly assigned to wear rigid gas permeable contact lenses or soft contact lenses. Both groups are then examined each year for three years to determine which group progresses the most in nearsightedness.

Annual examinations include assessment of the children's ability to focus their eyes, their eye glass prescription, the length of their eyes, detailed maps of the shape and thickness of their corneas (the clear window on the front of the eye), the shape of their eyes, and the curvature of the lens inside the eye. Their eye glass prescription is determined when the children's eyes are dilated. We examined 222 children for eligibility. Out of the 222 children, 148 were eligible to participate in the run-in period. Of the 148 eligible children, 116 (78.5%) were able to adapt to rigid gas permeable contact lens wear. All of the children were examined at The Ohio State University College of Optometry.

Study Design





The Ohio State University College of Optometry
United States




National Eye Institute (NEI)

Results (where available)

View Results


Published on BioPortfolio: 2014-07-24T14:35:11-0400

Clinical Trials [183 Associated Clinical Trials listed on BioPortfolio]

The Use of Atropine 0.01% in the Prevention and Control of Myopia (ATOM3)

Study of low dose atropine in preventing the onset and progression of myopia in high risk children with pre-myopia or low-myopia.

Cambridge Anti-Myopia Trial: Accommodation Training and Aberration Control in Myopia Development

We have identified focussing problems related to myopia getting worse. Our trial uses optical and orthoptic interventions that correct the focussing problems to see if this retards myopia ...

Eye Drops Study for Myopia Control in Schoolchildren

The myopia prevalence in schoolchildren is high in Taiwan. The myopia progression is fast in children and often associated high myopia in later life. This prospective and randomized study ...

Does Undercorrection of Myopia Retard Myopia Progression Among Kindergarten Children?

The purpose of this study is to find out if undercorrection of myopia slow down the progression of myopia in kindergarten children.

Topical Application of Low-concentration (0.01%) Atropine on the Human Eye With Fast and Slow Myopia Progression Rate

Our project is a 24-month longitudinal randomized controlled trial that aims to investigate the myopia development after topical application of 0.01% atropine in children with either fast ...

PubMed Articles [82 Associated PubMed Articles listed on BioPortfolio]

Progress and Control of Myopia by Light Environments.

During the past 30 years, the prevalence rate of myopia has been increased dramatically. Myopia has become one of the leading causes of vision loss in some countries, whereas the mechanism of the main...

Controlling Progression of Myopia: Optical and Pharmaceutical Strategies.

The burden associated with the rising prevalence of myopia and high myopia, and the associated vision impairment and sight-threatening complications, has triggered the need to evaluate strategies to c...

Possible increase of myopia prevalence among children in Sweden.

The purpose of this study was to determine the prevalence of myopia in a population of children in Sweden. Retrospective analysis of children in a region in Sweden referred to eye care from the nation...

Myopia: is the nature-nurture debate finally over?

In the nineteenth century, the prevalence of myopia began to rise, and Cohn stressed the role of education. Later, based on twin studies, Sorsby argued that refraction was almost totally genetically d...

Dim Light Exposure and Myopia in Children.

Experimental myopia in animal models suggests that bright light can influence refractive error and prevent myopia. Additionally, animal research indicates activation of rod pathways and circadian rhyt...

Medical and Biotech [MESH] Definitions

Excessive axial myopia associated with complications (especially posterior staphyloma and CHOROIDAL NEOVASCULARIZATION) that can lead to BLINDNESS.

Plastic surgery of the SCLERA. This procedure is used frequently to prevent blindness and poor vision in patients, especially children, with MYOPIA.

A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.

Detachment of the corpus vitreum (VITREOUS BODY) from its normal attachments, especially the retina, due to shrinkage from degenerative or inflammatory conditions, trauma, myopia, or senility.

A refractive error in which rays of light entering the EYE parallel to the optic axis are brought to a focus in front of the RETINA when accommodation (ACCOMMODATION, OCULAR) is relaxed. This results from an overly curved CORNEA or from the eyeball being too long from front to back. It is also called nearsightedness.

More From BioPortfolio on "The Contact Lens and Myopia Progression (CLAMP) Study"

Quick Search


Relevant Topics

Pediatrics is the general medicine of childhood. Because of the developmental processes (psychological and physical) of childhood, the involvement of parents, and the social management of conditions at home and at school, pediatrics is a specialty. With ...

Ophthalmology is the branch of medicine that is devoted to the study and treatment of eye diseases. As well as mild visual defects correctable by lenses, ophthalmology is concerned with glaucoma, uveitis and other serious conditions affecting the eye, ...

Searches Linking to this Trial