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The Effect of a Scleral Lens on the Anterior Chamber Depth and Minimum Rim Width

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT03926975
Recruitment Status : Completed
First Posted : April 25, 2019
Last Update Posted : January 2, 2020
Information provided by (Responsible Party):
MKWalker, University of Houston

Tracking Information
First Submitted Date  ICMJE April 18, 2019
First Posted Date  ICMJE April 25, 2019
Last Update Posted Date January 2, 2020
Actual Study Start Date  ICMJE June 1, 2018
Actual Primary Completion Date June 15, 2019   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: April 24, 2019)
Change in minimum rim width from baseline to 6-hours SL wear [ Time Frame: at baseline, after 2-hours lens wear, and after 6-hours lens wear ]
The Bruch's membrane opening to the inner limiting lamina (termed the minimum rim width) will be measured at the optic nerve head.
Original Primary Outcome Measures  ICMJE Same as current
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: April 24, 2019)
  • Intraocular pressure (IOP) [ Time Frame: at baseline, after 2-hours lens wear, and after 6-hours lens wear ]
    IOP will be measured using the Diaton and iCare tonometers
  • Anterior Chamber Depth (ACD) [ Time Frame: at baseline, after 2-hours lens wear, and after 6-hours lens wear ]
    ACD will be measured with the Lenstar A-scan
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title  ICMJE The Effect of a Scleral Lens on the Anterior Chamber Depth and Minimum Rim Width
Official Title  ICMJE The Effect of a Scleral Lens on the Anterior Chamber Depth and Minimum Rim Width
Brief Summary The purpose of this study is to evaluate the use of two instruments to measure changes in two ocular structures: 1) the anterior chamber depth (ACD) - measured using low coherence optical biometry, and 2) minimum rim width of the optic nerve head (MRW) - measured using optical coherence tomography. Changes in these ocular structures indicate fluctuations in intraocular pressure (IOP) and will be measured during scleral contact lens (SGP) wear to determine if SGP wear influences IOP. We hypothesize that a scleral lens increases the intraocular pressure (IOP) during active wear and that the ACD and MRW will also change.
Detailed Description

Contact lenses are often used to correct vision blur. The most common types of contact lenses include those referred to as 'soft' and 'rigid'. Visual acuity through rigid lenses often surpasses that of soft lenses. Historically, these lenses have been small in diameter, and hence patients also felt discomfort when wearing the lenses. Scleral lenses are relatively new, customized devices that have gained popularity with patients and practitioners in the past 5-10 years, because they are more comfortable and provide more stable vision than the small diameter rigid contact lenses. However, relatively little is known about the physiologic response of the eye to the scleral lens, or the long-term effects of their use, since they are such a new modality.

Maintaining the IOP within the eye is imperative to prevent damage to ocular tissue, which can occur in glaucoma. Given the landing of scleral lens overlying the sclera and ciliary body, which assist in modulating the transport of fluid in the eye, there is a potential for these lenses to impinge on fluid drainage which could lead to increases of IOP during scleral lens wear. The placement of the lens creates an obstacle in evaluating IOP while the lens is actually on the eye (covering the cornea), and since increases in IOP may only occur during lens wear, which is removed when determining clinical IOP measurements, it is difficult to monitor IOP during scleral lens wear with traditional IOP instrumentation (ie. iCare, Goldman, etc).

Optical coherence tomography is a non-invasive imaging technology that has revolutionized how the retina and optic nerve are clinically evaluated. The optic nerve head is typically assessed using radial scans, from which the minimal distance from the Bruch's membrane opening to the inner limiting lamina is quantified as the minimum rim width (MRW). With changes in IOP, the MRW is known to also change in thickness. Many studies are investigating the MRW changes during IOP fluctuations, with studies finding a decrease in MRW during acute IOP increase. In this project, MRW will be used to indirectly assess changes in IOP by measuring the MRW periodically during active scleral lens wear.

In addition, we are incorporating low coherence optical biometry (Lenstar) to evaluate the effect of the scleral lens pressure on the anterior chamber. Using the Lenstar, corneal thickness, anterior chamber depth (ACD), lens thickness and vitreous chamber depth can be quantified. In this project, ACD will be used to indirectly evaluate changes in the pressure within the anterior chamber. The assumption is that the ACD will change based on changes in pressure in the scleral lens tear reservoir.

This study will add to the knowledge of how the scleral lens affects the dynamic pressure system of the eye. Based on the implications for disease with chronic increases and fluctuations in IOP, this is important information to understand with the scleral lens, a relatively new refractive treatment modality.

Study Type  ICMJE Interventional
Study Phase  ICMJE Not Applicable
Study Design  ICMJE Allocation: Randomized
Intervention Model: Single Group Assignment
Intervention Model Description:
Subjects are all non-scleral lens wearers. One eye (test) will be selected to wear a scleral lens, and the contralateral eye (control) will not wear any lens.
Masking: None (Open Label)
Primary Purpose: Basic Science
Condition  ICMJE Ocular Hypertension
Intervention  ICMJE
  • Device: Scleral Lens
    The contact lens will be worn on one eye.
  • Other: No lens
    No lens worn on the contralateral control eye
Study Arms  ICMJE
  • Experimental: Experimental: Scleral Lens
    One eye will be randomly selected to wear a scleral lens for a 6-hour testing period.
    Intervention: Device: Scleral Lens
  • Active Comparator: Control: no lens
    The contralateral eye will not wear a lens.
    Intervention: Other: No lens
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status  ICMJE Completed
Actual Enrollment  ICMJE
 (submitted: April 24, 2019)
Original Estimated Enrollment  ICMJE Same as current
Actual Study Completion Date  ICMJE August 30, 2019
Actual Primary Completion Date June 15, 2019   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • young, normal individuals

Exclusion Criteria:

  • IOP > 20mm in either eye, and h/o ocular hypertension, glaucoma, or ocular surgery that can affect IOP.
  • h/o scleral lens wear or current scleral lens wear
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years to 60 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE United States
Removed Location Countries  
Administrative Information
NCT Number  ICMJE NCT03926975
Other Study ID Numbers  ICMJE STUDY00000747
Has Data Monitoring Committee No
U.S. FDA-regulated Product
Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Device Product Not Approved or Cleared by U.S. FDA: Yes
Product Manufactured in and Exported from the U.S.: No
IPD Sharing Statement  ICMJE Not Provided
Responsible Party MKWalker, University of Houston
Study Sponsor  ICMJE University of Houston
Collaborators  ICMJE Not Provided
Investigators  ICMJE Not Provided
PRS Account University of Houston
Verification Date December 2019

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP