Clinical Evaluation of Modified 2.2mm Microincision Phacoemulsification for Age-related Cataract

Study Overview
=================
Brief Summary
-----------------
This study is a single-center, parallel-group, randomized controlled trial with the following objectives: to compare the incidence of post-operative descemet membrane detachment (DMD) in phacoemulsification surgery between modified and conventional 2.2mm microincision.

Detailed Description
-----------------
2.2mm incision is considered an ideal incision size in phacoemulsification. However, DMD is a common and serious complication in 2.2mm microincision phacoemulsification for hard nucleus age-related cataract. DMD is originated from the incision in the operation. How to construct the appropriate incision shape and size for reducing the occurrence of DMD is an important problem to be solved urgently in phacoemulsification surgery. The investigators found that enlarging the internal incision could increase the range of motion of surgical instruments and reduce the friction of instruments to incision. Therefore，the incidence of DMD would be reduced. The investigators developed this technique, modified 2.2mm incision, to reduce the incidence of incision-site DMD and not to increase other incision related complications. In this trial, the investigators aim to compare modified and conventional 2.2mm incision with regard to safety and efficacy in reducing the incidence of DMD.

Official Title
-----------------
Clinical Evaluation of Modified 2.2mm Microincision Phacoemulsification for Age-related Cataract

Conditions
-----------------
Cataract

Intervention / Treatment
-----------------
* Procedure: modified 2.2mm microincision
* Procedure: conventional 2.2mm microincision


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Aged-related cataract patients between 65 and 90 years ; Lens nuclear opalescence grade ≥4.0 on the Lens Opacities Classification System III (LOCS III); Scheduled for phacoemulsification combined with intraocular lens implantation. The number of corneal endothelial cells > 1500cells/mm2. Dilated pupil diameter ≥6mm Exclusion Criteria: A history of ophthalmic trauma or surgery; Other ophthalmic diseases such as glaucoma, uveitis, high myopia; Ocular factors that would make surgery challenging or dangerous, including but not limited to small pupil, shallow anterior chamber, etc.

Ages Eligible for Study
-----------------
Minimum Age: 65 Years
Maximum Age: 90 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: modified 2.2mm micoincision<br> | Procedure: modified 2.2mm microincision<br>* enlarging the internal incision about 0.4mm for conventional 2.2mm coaxial microincision phacoemulsification<br>|
| Active Comparator: conventional 2.2mm microincision<br> | Procedure: conventional 2.2mm microincision<br>* conventional 2.2mm coaxial microincision phacoemulsification<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of DMD at postoperative day 1 | Incidence of incision-site descemet membrane detachment observed by anterior segment OCT at postoperative day 1 | postoperative day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| maximal incision thickness | maximal incision thickness measured by anterior segment OCT at postoperative day 1, day 7, month 1, month 3 | postoperative day 1, day 7, month 1, month 3 | 
| surgical induced-astigmatism | surgical induced-astigmatism was calculated at each postoperative visit using the following equation: K2 = [K1 2 + K32 -2 K1 K3 cos (2θ3 -2θ1)]1/2 | postoperative day 1, day 7, month 1, month 3 | 
| the length of DMD | the length of incision-site descemet membrane detachment measured by anterior segment OCT at postoperative day 1, day 7, month 1, month 3 | postoperative day 1, day 7, month 1, month 3 | 
| Best corrected visual acuity (BCVA) | Best corrected visual acuity (BCVA) is evaluated with an ETDRS chart at each postoperative visit | postoperative day 1, day 7, month 1, month 3 | 
| modulation transfer function (MTF)-cut off | modulation transfer function (MTF)-cut off measured by itrace at each postoperative visit | postoperative day 1, day 7, month 1, month 3 | 
| central cornea endothelial cell loss | Central cornea endothelial cell loss was calculated on the basis of preoperative and postoperative endothelial cell density. | postoperative day 1, day 7, month 1, month 3 |