Prevalence of Corneal Astigmatism Before Glaucoma Surgery in Chinese Patients With Primary Angle-closure Glaucoma

Study Overview
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Brief Summary
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Clear-lens extraction has been considered as first-line therapy for primary angle closure glaucoma(PACG) and application of toric intraocular lens (IOLs) leads to better postoperative visual acuity, yet little is known about the prevalence of corneal astigmatism in PACG patients. We intend to make biometry examination for Chinese PACG patients, to obtain keratometry (K) , axial length (AL) and so on, and demographics data will also be recorded. We will study the prevalence of corneal astigmatism before glaucoma surgery in Chinese patients with PACG. Furthermore, differences of corneal astigmatism between primary angle-closure glaucoma and cataract patients will be explored. Finally, the prevalence of corneal astigmatism before glaucoma surgery in Chinese patients with PACG will be portrayed and can be instructive to the IOLs' manufactering.

Detailed Description
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Biometry examination contains keratometry (K) , axial length (AL), central anterior chamber depth, visual field loss(mean deviation, MD), choroidal thickness(CT), range of goniosynechia, and stage of PACG. Demographics data contains age, gender, and eye.

Official Title
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Prevalence of Corneal Astigmatism Before Glaucoma Surgery in Chinese Patients With Primary Angle-closure Glaucoma

Conditions
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Glaucoma, Angle-Closure, Astigmatism

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who are phakic and aged 40 years or older , and had newly diagnosed primary angle closure with intraocular pressure 30 mm Hg or greater or primary angle-closure glaucoma, will be recruited during preoperative screening at Zhongshan Ophthalmic Center. Exclusion Criteria: Patients with corneal disease, irregular astigmatism, previous corneal or intraocular surgery, or a history of ocular inflammation will be excluded.

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of corneal astigmatism | Data of corneal astigmatism will be acquired through examination,and different types of corneal astigmatism will be diagnosed and seperated.Moreover,we will analyse the prevalence of corneal astigmatism,and compare among different age groups and different genders.Correlation between demographic features and data will be analysed,too. | During preoperative screening (1 day) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of keratometry | Flat,steep and mean keratometry will be examined before glaucoma surgery. Moreover,we will analyse the prevalence of corneal astigmatism,and compare among different age groups and different genders. | During preoperative screening (1 day) | 
| Prevalence of axial length | Axial length will be measured by both IOL Master and A-scan, and data will be compared between different measurements,different genders and different age groups. | During preoperative screening (1 day) |