Topics

Binocular Vision Anomalies After Cataract and Refractive Surgery

2018-07-26 12:30:17 | BioPortfolio

Summary

There are indications in the literature that binocular vision disorders may occur after cataract and corneal refractive surgery. It is not clear whether these problems are new or represent decompensation of previously existing conditions. However, the following significant study limitations exist in the current literature: 1) lack of attention to non-strabismic binocular vision disorders, 2) incomplete binocular vision assessment, 3) a validated symptom survey was not used, 4) diplopia was typically the only symptom studied, 5) retrospective study design, and 6) in the few prospective studies the sample sizes were small.

Given the limitations in the current literature there is a need for further study of the prevalence and significance of binocular vision problems after cataract surgery and binocular vision and accommodative problems after corneal refractive surgery.

This study aims to determine whether there is an increase in the prevalence of binocular vision problems after cataract surgery and accommodative and binocular vision disorders after refractive surgery.

Description

1. Research plan Specific aim 1A: To investigate the prevalence of non-strabismic and strabismic binocular vision anomalies after cataract surgery. Specific aim 1B: To investigate the prevalence accommodative and binocular vision disorders after refractive surgery. Specific aim 2: To determine if increase in the prevalence of binocular anomalies is different for cataract surgery compared to refractive surgery. Specific aim 3: To develop an efficient examination protocol that would enable eye care professionals to determine if a patient is at risk for binocular vision anomalies after cataract surgery and accommodative and binocular vision disorders after refractive surgery.

The proposed study will address the weaknesses in the current literature. The study will be prospective and will use explicit and well-defined eligibility and exclusion criteria. A comprehensive battery of accommodative (pre-presbyopes only) and binocular vision tests will be administered on all the patients before the surgery of the first eye and 12 weeks after the surgery of the second eye.

A pre-defined classification protocol will be used to determine if a binocular vision disorder is present before surgery, after surgery, or whether there has been a change in the condition after surgery.

A total prevalence of postoperative strabismic and non-strabismic binocular vision anomalies will be determined for the cataract population and the refractive error group.

2. Statistical analysis plan 2.1 Specific aim 1A Hypothesis: There will be a statistically significant increase in the prevalence of binocular vision anomalies after cataract surgery

A sample size calculation based on a McNemar's test to compare the prevalence of binocular vision anomalies before and after cataract surgery was performed using the Power and Sample Size Program (PS version 3.1.2). Base on a previous literature, the overall prevalence of accommodative and binocular vision anomalies in adult population (18-35 years) is 13.15%. However, no existing literature reported the prevalence of binocular vision anomalies after cataract surgery.

We propose that 15% increase in prevalence is clinically meaningful. The correlation between paired observations is 0.2, as recommended by Dupont. Although this is a large effect, the effect of cataract surgery on prevalence of binocular vision anomalies may be this large (presumed by an experienced binocular vision specialist). If the effect is smaller and the difference not statistically significant, the study will provide valuable data to plan another study. Therefore, a sample size calculation suggests that a total of 44 participants will yield a power of 80% with a significant level of 5%. To account for potential loss to follow-up, a sample size of 50 will be selected for the cataract group. All analyses will be performed using SPSS Statistics 24.0 with an alpha level of 0.05 to determine the statistical significance. A calculation for the prevalence of binocular vision anomalies before and after surgery will be performed. A two-tailed McNemar's Chi-Square Test will be used to test the statistical significance of the change in the proportion of binocular vision anomalies before and after surgery.

2.2 Specific aim 1B Hypothesis: There will be a statistically significant increase in the prevalence of binocular vision and accommodative anomalies after refractive surgery.

The sample size calculation process for specific aim 1B was the same as for specific aim 1A. Therefore, a sample size of 50 will also be selected for the refractive error group. A calculation for the prevalence of accommodative and binocular vision anomalies before and after surgery will be performed. A two-tailed McNemar's Chi-Square Test will be used to test the statistical significance of the changes in the proportions of binocular vision anomalies before and after surgery.

2.3 Specific aim 2 Hypothesis: The increase in prevalence of binocular vision anomalies will be greater after cataract surgery than refractive surgery.

A calculation for the prevalence of binocular vision anomalies will be performed respectively in the cataract group and the refractive error group. A two-tailed Contingency Chi-Square Test will be used to test the statistical significance of difference of changes in the proportion of binocular vision anomalies before and after surgery in both groups.

2.4 Specific aim 3 Hypothesis: A short screening protocol will be of equal effectiveness to a comprehensive assessment of binocular vision and accommodation to determine which patients may be at risk for post-surgical binocular vision and accommodative anomalies.

A two-tailed MacNemar's Chi-Square Test will be used to test the statistical significance of difference in the effectiveness of a short screening protocol and a comprehensive assessment for determining the risk for post-surgical binocular vision and accommodative anomalies. Sensitivity and specificity for the short screening protocol will be calculated.

Study Design

Conditions

Binocular Vision Disorder

Intervention

cataract surgery, Corneal refractive surgery

Location

Salus University
Elkins Park
Pennsylvania
United States
19027

Status

Not yet recruiting

Source

Salus University

Results (where available)

View Results

Links

Published on BioPortfolio: 2018-07-26T12:30:17-0400

Clinical Trials [8205 Associated Clinical Trials listed on BioPortfolio]

Effect of TrueTear Corneal Surface Imaging

This study will evaluate the utility of TrueTear™ to improve anterior corneal surface imaging quality before cataract surgery, refractive lens exchange, or laser refractive surgery.

The Effect Of Lifitegrast On Refractive Accuracy And Symptoms In Dry Eye Patients Undergoing Cataract Surgery

To determine if Xiidra® lifitegrast plays a role in the refractive accuracy when administered to patients preoperatively who are scheduled for cataract surgery and have a tear break up ti...

Auditing of Poor Visual Outcomes After Un-eventual Cataract Surgery

Globally, cataract is the major cause of blindness accounting for 51% of total blindness and there are regional variations in it. Today, cataract surgery is a highly successful and cost-ef...

Visual Acuity After the Combined Binocular Implantation of +2.0 Diopters and +3.0 Diopters Oculentis Multifocal Intraocular Lenses.

The objective of this study is to assess the visual outcome after the combined binocular implantation of +2.0 D and +3.0 D refractive multifocal intraocular lenses.

Accuracy of the Pentacam and IOL Master to Calculate the Effective Corneal Power After Corneal Refractive Surgery

The purpose of this study is to determine the accuracy of the Pentacam and IOL Master to calculate the effective corneal power (keratometry, corneal curvature) in patients who have undergo...

PubMed Articles [17242 Associated PubMed Articles listed on BioPortfolio]

Evaluation of Different IOL Calculation Formulas of the ASCRS Calculator in Eyes After Corneal Refractive Laser Surgery for Myopia With Multifocal IOL Implantation.

To compare the accuracy of different intraocular lens (IOL) calculation formulas available on the American Society of Cataract and Refractive Surgery (ASCRS) post-refractive surgery IOL power calculat...

ASCRS calculator formula accuracy in multifocal intraocular lens implantation in hyperopic corneal refractive laser surgery eyes.

To evaluate the accuracy of different intraocular lens (IOL) power calculation formulas available on the American Society of Cataract and Refractive Surgery calculator in calculating multifocal IOL po...

Heads-up Cataract Surgery: Complication Rates, Surgical Duration, and Comparison With Traditional Microscopes.

To compare the complication rates and surgical duration between a three-dimensional visualization system (heads-up surgery) and traditional binocular microscope in cataract surgery.

Peri-/postoperative Antiinflammation Therapy after Cataract and Refractive Surgery.

Cataract surgery is the most frequently performed surgery worldwide, and refractive surgery is gaining more and more popularity. Although they are rare, some possible complications of these procedures...

Methods for evaluating quality of life and vision in patients undergoing lens refractive surgery.

Cataract surgery has evolved into a procedure that generally yields the best postoperative refractive result attainable. Patients with multifocal intraocular lenses (IOLs) present higher rates of spec...

Medical and Biotech [MESH] Definitions

Loss of CORNEAL ENDOTHELIUM usually following intraocular surgery (e.g., cataract surgery) or due to FUCHS' ENDOTHELIAL DYSTROPHY; ANGLE-CLOSURE GLAUCOMA; IRITIS; or aging.

Surgical techniques on the CORNEA employing LASERS, especially for reshaping the CORNEA to correct REFRACTIVE ERRORS.

The study and treatment of defects in binocular vision resulting from defects in the optic musculature or of faulty visual habits. It involves a technique of eye exercises designed to correct the visual axes of eyes not properly coordinated for binocular vision.

A type of refractive surgery of the CORNEA to correct MYOPIA and ASTIGMATISM. An EXCIMER LASER is used directly on the surface of the EYE to remove some of the CORNEAL EPITHELIUM thus reshaping the anterior curvature of the cornea.

Surgical procedures conducted with the aid of computers. This is most frequently used in orthopedic and laparoscopic surgery for implant placement and instrument guidance. Image-guided surgery interactively combines prior CT scans or MRI images with real-time video.

More From BioPortfolio on "Binocular Vision Anomalies After Cataract and Refractive Surgery"

Quick Search

Relevant Topics

Ophthalmology
Ophthalmology is the branch of medicine that is devoted to the study and treatment of eye diseases. As well as mild visual defects correctable by lenses, ophthalmology is concerned with glaucoma, uveitis and other serious conditions affecting the eye, ...

Surgical treatments
Surgery is a technology consisting of a physical intervention on tissues. All forms of surgery are considered invasive procedures; so-called "noninvasive surgery" usually refers to an excision that does not penetrate the structure being exci...


Searches Linking to this Trial