Photorefractive Keratectomy for Severe Anisometropia and Isoametropia Associated With Amblyopia
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|ClinicalTrials.gov Identifier: NCT03610997|
Recruitment Status : Active, not recruiting
First Posted : August 2, 2018
Last Update Posted : January 19, 2021
|Condition or disease||Intervention/treatment||Phase|
|Anisometropia Hyperopia High Myopia Amblyopia Isometropic Amblyopia Bilateral High Astigmatism||Procedure: Photorefractive keratectomy||Not Applicable|
Anisometropia is a condition in which one eye has a significantly different refractive error from the other and commonly leads to the development of refractive amblyopia in the affected eye. High isoametropia is the condition in which both eyes have high refractive error and commonly leads to bilateral refractive amblyopia if untreated. Amblyopia is the condition in which vision does not develop fully in the brain due to disuse or misuse of one or both eyes. Typically, in high anisometropia, a contact lens in the eye with the stronger refractive error and/or glasses must be used to correct the refractive error. Commonly, infants and children with this condition refuse to wear the contact lens or glasses because the other eye sees normally. There are other problems in treating high anisometropia with glasses. One is aniseikonia, the condition of image size disparity between the two eyes. This causes difficulty for the brain of the affected person to fuse the images from the two eyes because the image from one eye is much larger than that from the other eye. This results in asthenopia (eye fatigue) and sometimes even diplopia. If the anisometropia is severe, significant amblyopia will result in the eye with the stronger refractive error and, if not treated at an early age, permanent and potentially severe vision loss will result.
In high isoametropia, contact lenses or glasses must likewise be used in order for normal vision to develop. Most children with isoametropia will wear glasses well because they cannot see well without them. By contrast, children with developmental delays, chromosomal abnormalities, autism, or attention deficit hyperactivity disorder and high isoametropia very commonly will not wear the needed refractive correction due to strong tactile aversion to anything touching the face or head. If the refractive error is high, significant bilateral (isoametropic) amblyopia will result and, if not treated at an early age, permanent and potentially severe vision loss will result.
PRK can normalize high refractive errors and potentially improve the amblyopia in affected children. The purpose of this study is to investigate whether children with high anisometropia or isoametropia with amblyopia that are nonresponsive to standard therapy and receive PRK develop better longterm visual acuity. Secondary outcomes are stability of refractive correction, and corneal health.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||200 participants|
|Intervention Model:||Single Group Assignment|
|Intervention Model Description:||Photorefractive Keratectomy|
|Masking:||None (Open Label)|
|Official Title:||Photorefractive Keratectomy for Anisometropic and Isoametropic Amblyopia in Children Refractory to Conventional Treatment|
|Actual Study Start Date :||January 1, 2001|
|Estimated Primary Completion Date :||August 1, 2028|
|Estimated Study Completion Date :||October 1, 2028|
The children will undergo PRK in the affected eye(s) using previously derived formulas for PRK.
Procedure: Photorefractive keratectomy
- Visual acuity [ Time Frame: 10 years ]Snellen equivalent
- Refractive error [ Time Frame: 10 years ]cycloplegic refraction
- Corneal clarity [ Time Frame: 10 years ]slit lamp exam
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03610997
|United States, Texas|
|Texas Children's Hospital|
|Houston, Texas, United States, 77030|
|Principal Investigator:||Evelyn Paysse, MD||Baylor College of Medicine|