Effect of the Timing of Cataract Surgery on Complications in Patients With Bilateral Congenital Cataracts

Study Overview
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Brief Summary
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Congenital cataract is an important treatable cause of visual handicap in childhood throughout the world. Successful management of childhood cataract is dependent on individualized treatment strategies and rigorous postoperative supervision for adverse complication. In this trial, we aimed to compare the difference of postoperative outcome between surgical timing at age of 3 month and 6 month. Patients enrolled into the study will be followed for two year and will have study visits at 1 day, 1 week, 1 month, 3 month, 6 month, 9 month, 12 month, 18month and 24month postoperatively.

Detailed Description
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Congenital cataract is a priority of Vision 2020: the Right to Sight, the global initiative to reduce the world's burden of avoidable blindness, because it is an important treatable cause of visual handicap in childhood throughout the world. Successful management of childhood cataract is dependent on individualized treatment strategies and postoperative supervision for adverse complication is also essential. The timing of surgery of childhood cataract depends on the etiology and on the degree of visual interference. Severe bilateral cataracts with significant obstruction of the visual axis must be treated and surgery is recommended as soon as possible after discovery. Several previous studies claimed that ideally cataracts should be removed before 3 months of age, while the result of recent researches shows that too early intervention for cataract surgery seems aggressive and would cause serious complications, which might cause poor long-term visual outcomes. Therefore, in order to control childhood blindness and severe visual impairment in China, it is of great importance to ensure that pediatric patients with cataract could have good timing of surgery, postoperative rigorous supervision, accurate optical rehabilitation and comprehensive treatment of amblyopia. In this trial, we aimed to compare the difference of postoperative outcome between surgical timing at age of 3 month and 6 month. Patients enrolled into the study will be followed for two year and will have study visits at 1 day, 1 week, 1 month, 3 months, 6 months, 9 months, 12 months, 18months and 24months after cataract surgery.

Official Title
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Effect of the Timing of Lens-removal Cataract Surgery on Postoperative Complications Rate Among Patients With Bilateral Congenital Cataracts

Conditions
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Cataract

Intervention / Treatment
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* Procedure: Phacomulsification lens removal cataract surgery without Intraocular lens(IOL) implantation at the age of 3month of the patients
* Procedure: Phacomulsification lens removal cataract surgery without Intraocular lens(IOL) implantation at the age of 6 month of the patients
* Drug: Subconjunctival dexamethasone and general anesthesia


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Children diagnosis with bilateral congenital cataract for entire lens without other ocular abnormality No more than 3 month old Have signed a consent form Can be followed Exclusion Criteria: Children not identified with congenital cataract Have not signed consent form Be not able to be followed

Ages Eligible for Study
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Maximum Age: 3 Months

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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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 3 month surgical group<br>Phacoemulsification pediatric cataract surgery is performed at the age of 3 month of patients without IOL implantation. | Procedure: Phacomulsification lens removal cataract surgery without Intraocular lens(IOL) implantation at the age of 3month of the patients<br>* The surgical timing of phacoemulsification is perform at the age of 3 month of the patients. During Phacoemulsification, viscoelastic materials and anterior lens capsule are used to protect corneal endothelial cells.<br>Drug: Subconjunctival dexamethasone and general anesthesia<br>* All patients received subconjunctival dexamethasone (2 mg) during surgery, and all surgeries were performed under general anesthesia.<br>|
| Experimental: 6 month surgical group<br>Phacoemulsification pediatric cataract surgery is performed at the age of 3 month of patients without IOL implantation.. | Procedure: Phacomulsification lens removal cataract surgery without Intraocular lens(IOL) implantation at the age of 6 month of the patients<br>* The surgical timing of phacoemulsification is perform at the age of 6 month of the patients. During Phacoemulsification, viscoelastic materials and anterior lens capsule are used to protect corneal endothelial cells.<br>Drug: Subconjunctival dexamethasone and general anesthesia<br>* All patients received subconjunctival dexamethasone (2 mg) during surgery, and all surgeries were performed under general anesthesia.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in the central subfield thickness (CST) measured by Optical Coherence Tomography(OCT) |  | during surgery,postoperation time:1day,1week,1month,3month,6month,9month,12month,18month,24month | 
| Change from baseline in the thickness of the inner retinal layer regions measured by Optical Coherence Tomography(OCT) |  | during surgery,postoperation time:1day,1week,1month,3month,6month,9month,12month,18month,24month | 
| Change from baseline in the thickness of the outer retinal layer regions measured by Optical Coherence Tomography(OCT) |  | during surgery,postoperation time:1day,1week,1month,3month,6month,9month,12month,18month,24month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with abnormal intraocular pressure or diagnosis with secondary glaucoma |  | 2 year after surgery | 
| Number of participants undergoing Nd:YAG laser capsulotomy due to severe posterior capsular opacification（PCO） |  | 2 year after surgery |