Clinical Trial: Aqueous Humor Dynamics and Uveitic Glaucoma

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational

Official Title: The Contribution of Altered Aqueous Dynamics in the Development of Raised Intraocular Pressure in Patients With Uveitis

Brief Summary:

Uveitis is a disease that affects over 2 million people around the globe, and can ultimately lead to blindness. The proportion of patients with uveitis who become blind has not been reduced over the past 30 years, and this is therefore an area that demands further research. One of the major causes of blindness in uveitic patients is the development of uveitic glaucoma, which occurs in 10-20% of uveitic eyes. This is likely to occur for reasons related to the uveitis itself, but can also be caused as a side effect of the corticosteroids used to treat uveitis. The raised IOP in uveitis is more difficult to treat than other types of glaucoma.

To enable more effective treatment of uveitic glaucoma, the investigators need to understand more clearly the mechanisms which underlie this process. The investigators therefore propose a study to examine the contribution of altered aqueous dynamics to the development of raised IOP in uveitis.


Detailed Summary:

The investigators propose to undertake a cross-sectional observational study of patients with recurrent idiopathic acute anterior uveitis, to determine the relative contributions of altered aqueous production and drainage to the development of raised IOP in these patients.

Methods

Study Design A cross sectional observational study

Patient Selection All subjects attending the uveitis and glaucoma clinics at St Thomas' Hospital will be eligible to be included in the study if they fulfil the inclusion/exclusion criteria as below.

30 patients will be included from each of these three group of patients: 1) recurrent (> 5 attacks) idiopathic acute anterior uveitic with raised intraocular pressure; 2) recurrent (> 5 attacks) idiopathic acute anterior uveitic without raised intraocular pressure; 3) healthy age matched volunteers as controls. Patients on glaucoma treatment will be washed out for one month before measurement.

Examination Schedule and Methods

  1. Visual acuity:

    Visual acuity is measured before pupil dilation, tonometry, gonioscopy, or any other technique that could affect vision. Two different techniques are used to measure visual acuity, including Snellen and ETDRS visual acuity testing. Refraction is performed prior to formal measurement of visual acuity by either technique.

    Subjective Refraction:

    It is permissible to use a phoropter or trial frame to determine best-corrected Snellen visual a
    Sponsor: Guy's and St Thomas' NHS Foundation Trust

    Current Primary Outcome:

    • Intraocular pressure [ Time Frame: Four times during the morning on day 1 (study completion) ]
      Intraocular pressure (measured by Goldmann tonometry).
    • Facility of outflow [ Time Frame: day 1 only (study completion) ]
      Tonographic outflow facility (C) will be performed using an electronic Schiøtz tonographer (Model 720, Berkeley Bioengineering Inc, USA) at 10AM
    • Rate of aqueous flow (measured by fluorophotometry). [ Time Frame: Four times during the morning through day 1 only (study completion) ]
      Fluorophotometry will be performed in both eyes using a scanning ocular fluorophotometer from 9AM to 12PM (FM-2, Fluorotron Master Ocular Fluorophotometer; OcuMetrics, Mountain View, California). The aqueous turnover protocol will be used to calculate the aqueous flow rate. Duplicate or triplicate scans will be collected and repeated at 1 hour intervals for 4 measurements to determine the aqueous flow rate (Ft).


    Original Primary Outcome: Same as current

    Current Secondary Outcome:

    Original Secondary Outcome:

    Information By: Guy's and St Thomas' NHS Foundation Trust

    Dates:
    Date Received: April 27, 2016
    Date Started: August 2013
    Date Completion: March 2017
    Last Updated: May 5, 2016
    Last Verified: April 2016