The effects of glaucoma medication on the ocular surface

  • Sunayna Verma-Mistry

Student thesis: Doctoral ThesisDoctor of Philosophy


The aim of this research was to establish the effects of glaucoma medication on the ocular surface. It is well known that ocular surface disease (OSD) is a prevalent issue in medically treated glaucoma and ocular hypertension (OHT) patients. The cause of this has often been attributed to the preservatives which are added to the ocular hypotensive drops used in the management of glaucoma and OHT. Though preservative-free (PF) alternatives would provide the best benefit-to-risk ratio, it is not cost effective to prescribe these to every patient attending glaucoma clinics. There is a need, therefore, to decipher which individuals are most at risk to developing OSD in their lifetime, when treated for glaucoma or OHT.

This thesis sought to address the issue surrounding OSD in glaucoma clinics through the compilation of a series of investigations looking at; the efficacy, safety and tolerability of preserved versus PF medication, current clinical approaches to OSD in UK glaucoma clinics, adherence rates in glaucoma treatment, the prevalence of OSD and Dry Eye Disease (DED) in glaucoma prior to the initiation of treatment, and the predisposing factors associated with developing OSD and DED when medically managed for glaucoma or OHT.

In turn, this thesis has found
• Preservative-free ocular hypotensive drops to be just as effective as preserved drops in lowering the intraocular pressure (IOP), with better tolerability.
• OSD is highly prevalent in glaucoma clinics, and using the Tear Film &
Ocular Surface Society Dry Eye WorkShop II (TFOS DEWS II) Diagnostic test battery for OSD, levels are >96% amongst new, follow up and treated patients
• Cost is the biggest barrier for clinicians in prescribing PF treatment.
• There is room for improvement in patient education regarding drop instillation technique, information at diagnosis and written aids to support such advice.
• Glaucoma clinics need to establish routine ocular surface checks for optimal co-management of glaucoma/OHT and OSD.
• More robust research is required to determine predisposing factors to DED in medically managed glaucoma/OHT patients, but polypharmacy, alcohol consumption, blepharitis, thicker CCT, higher baseline IOP and tear break-up-time
Date of AwardJun 2022
Original languageEnglish
SupervisorPreeti Bhogal-Bhamra (Supervisor) & James Wolffsohn (Supervisor)


  • dry eye disease
  • glaucoma
  • ocular hypertension
  • ocular surface disease
  • preservatives
  • preservative-free
  • ocular hypotensive drops
  • eye drops

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