The Effects of BAK on the Blood Aqueous Barrier of Pseudophakic Patients
Condition: Dry Eye Syndromes
MeSH terms: Dry Eye Syndromes
Study type: Interventional
Phase: Phase 4

Summary: 
      BAK is one of the most frequent preservatives in eye drops. BAK is a quaternary ammonium salt
      with surfactant qualities. It can be bacteriostatic or bactericidal depending on the
      concentrations used. It has been shown to be effective against most bacteria with a few
      exceptions, such as Pseudomonas aeruginosa, or picornaviruses. It as been widely used in
      eyedrops, nose sprays, hand and face washes, mouthwashes, spermicidal creams, and in various
      other cleaners, sanitizers, and disinfectants. BAK gained popularity when it was first
      introduced because it also enhances corneal penetration of some drugs by causing epithelial
      separation.

      It is present in several ophthalmic formulations, including most of the antiglaucoma
      medications. If used chronically, BAK has been found to cause ocular surface changes, such as
      dry eye and punctuate keratitis. BAK has also been suggested to promote a break in the blood
      aqueous barrier, which may lead to undesirable consequences, such as uveitis and cystoid
      macular edema. However, this information is controversial. The purpose of this study is to
      evaluate the consequences of BAK on the blood-retinal and blood-aqueous barriers of
      pseudophakic patients receiving BAK-preserved lubricating drops.
    

Detailed description: 
      The primary hypothesis behind the study is that BAK may lead to a break in the blood-retina
      barrier in pseudophakic eyes, leading to an increase in macular thickness, compared to a
      non-BAK containing solution. The secondary hypothesis is that solutions containing BAK will
      increase the permeability of the blood aqueous barrier compared to non-BAK solutions. If the
      hypotheses are confirmed, they may serve as a contraindication to the use of BAK-preserved
      drops in pseudophakic eyes requiring chronic use of medications.

      This is a prospective, randomized, examiner-masked, controlled study involving 44
      pseudophakic eyes of 44 patients. Patients receiving any other eyedrop, with a previous
      history of uveitis, posterior capsule rupture or any other ophthalmic surgery will be
      excluded. Patients will be randomized to the use of a BAK-preserved lubricating drop or to
      the use of a non-preserved lubricating drop q.i.d for one month. Effects on the blood aqueous
      barrier will be objectively measured with a laser flare meter (Kowa, Japan) at baseline, 15
      days and one month after inclusion. Patients will also have OCT images (Cirrus, Zeiss, USA)
      of the macula at the same time intervals to evaluate the possible effects on the blood-retina
      barrier. Macular thickness and the presence of cystoid macular edema will be evaluated at
      each time interval.
    

Intervention name(s): Hydroxypropylmethylcellulose; Carboxymethylcellulose
Intervention type(s): Drug; Drug
Intervention description(s): 22 patients will receive this lubricating drop 4 times a day for 1 month; 22 patients will receive this lubricating drop 4 times a day for 1 month.
Other intervention name(s): Retin Active; Optive UD
Intervention MeSH terms: Carboxymethylcellulose Sodium
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Investigator)
Primary purpose: Treatment
Keywords: dry eye; pseudophakia; cornea; lubricating drop; BAK; blood aqueous barrier; blood-retina barrier