Abstract
Purpose: :
Glaucoma patients with poorer vision may be more motivated to use glaucoma therapies, yet their vision may impede accurate eye drop insertion. No studies have objectively evaluated glaucoma subjects with visual impairment (VI) or moderate or severe field loss. We objectively evaluate eye drop dosing in subjects with VI or moderate to severe field loss, and compared their ability with their perceptions.
Methods: :
This prospective study includes only experienced glaucoma patients with impaired vision (<20/60) or moderate or severe visual field loss (Hodapp Anderson) in at least one eye, who do not rely on others to administer drops. We defined VI as visual acuity 20/60 to 20/400 and blindness (B) as visual acuity of ≤20/400. We administered a questionnaire about the subjects’ history of eyedrop use, then video-recorded self-administration of sterile commercially available artificial tears in a 5 cc Boston Round Bottle. Subjects used their dominant hand to instill a drop onto the eye that had worse acuity or field damage. All videos were reviewed for number of drops instilled, location of the drop, distance from the eye, and possible contamination. We define "success" as the ability to get only 1 drop onto the eye without touch.
Results: :
We enrolled 117 subjects (46% men, 74% Caucasian, mean age 68 years). 92% used drops for > 1 year. 78% had severe field loss and 23% were B in at least one eye. Only 65% were able to get the drop onto the eye, and 39% placed just one drop on the eye without touching the adnexa. 32% touched the bottle to the eye or the eyelid. Of the 83 subjects who stated that they "never touched their eye with the bottle", 24% touched the eye or eyelid. Of the 104 who stated they had "no trouble" self-administering eyedrops, 60% were unsuccessful. This demonstrated poor patient perception of the actual situation. When comparing the subjects with bilateral versus unilateral impairment, similar proportions of subjects appeared to be successful in getting the drop onto the eye.
Conclusions: :
Video-recording in these VI subjects documented that they missed the eye, traumatized their corneas, and contaminated the bottletips. Subjects were unaware of this poor performance. This should be taken into account before prescribing IOP lowering medications in patients with VI. Glaucoma patients may progress despite topical therapy in part due to poor execution. Improved methods of medication delivery including better instruction and eye drop devices are needed.
Clinical Trial: :
www.clinicaltrials.gov NCT00760240
Keywords: clinical (human) or epidemiologic studies: health care delivery/economics/manpower • low vision • visual fields