Comparison of Pre-operative Measurements With Intraoperative Aberrometry in Predicting Correction for Low Toric Lens Correction in Cataract Surgery

Study Overview
=================
Brief Summary
-----------------
Examination of the accuracy of toric predictive power in patients with 1.5 diopters of astigmatism or less.

Detailed Description
-----------------
Based on preoperative keratometry and using the Baylor Nomogram and a standard factor for surgically-induced astigmatism, the investigators will calculate keratometry-based total astigmatism for each patient. This will be compared to aberrometry-based total astigmatism, i.e. the total astigmatism measured by ORA in each case. With this information the investigators will determine in what portion of patients keratometry-based total astigmatism vs aberrometry-based total astigmatism predicts a need for astigmatism correction, (i.e., total astigmatism is greater than or equal to 0.5 D) during cataract surgery.

Official Title
-----------------
Comparison of Pre-operative Measurements With Intraoperative Aberrometry in Predicting Needed Correction for Low Toric Lens Correction in Cataract Surgery

Conditions
-----------------
Cataract Surgery

Intervention / Treatment
-----------------
* Other: Intraoperative Aberrometry vs preoperative biometry


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients who underwent conventional (non-femtosecond) cataract surgery and whose data to be collected are accessible and available from the ORA database. Patients whose medical records show they did not exhibit any significant ocular morbidity that would be expected to influence outcome measures. Exclusion Criteria: Patients with visually significant co-morbidities (corneal, retina, optic nerve disease) that could affect their visual outcome or ability to be refracted after. Patients with surgical complications either during or after surgery (capsule tears, iris trauma, decentered IOL, cystoid macular edema, etc.) Patients with previous refractive surgery.
Sexes Eligible for Study
-----------------
All

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

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

Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Intraoperative Aberrometry vs Preoperative Biometry<br>Retrospective view of existing chart data. | Other: Intraoperative Aberrometry vs preoperative biometry<br>* Hypothesis: Intraoperative aberrometry measures lower levels of astigmatism more accurately than preoperative biometry in patients undergoing cataract surgery.<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of Patients requiring Astigmatism Correction | Proportion of patients requiring astigmatism correction, i.e., having need for astigmatism correction of greater than or equal to 0.5 D during cataract surgery, when measured by preoperative keratometry vs intraoperative aberrometry. | up to 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patients with Postoperative residual astigmatism 0.5 to 1.0 diopter | Looking at patients whose ORA-based total astigmatism was greater than or equal to 0.5 and less than or equal to 1.0 diopter, did patients receiving astigmatism correction have less postoperative residual astigmatism than those who did not receive astigmatism correction? | up to 3 months | 
| Patients with Postoperative residual astigmatism 1.0 to 1.5 diopter | Looking at patients whose ORA-based total astigmatism was greater than 1.0 and less than or equal to 1.5 diopter,m did patients receiving astigmatism correction have less postoperative residual astigmatism than those who did not receive astigmatism correction? | up to 3 months |