What rates of glaucoma progression are clinically significant?

Abstract

Clinically important rates of glaucoma progression (worsening) are ones that put a patient at risk of future functional impairment or reduction of vision-related quality of life. Rates of progression can be evaluated through measuring structural or functional changes of the optic nerve. Most treated eyes do not progress at rates that will lead to future visual impairment, but there are a significant proportion (3-17%) of eyes, that are at risk of impairment even under clinical care. While very fast rates of progression (e.g. MD progression of -1.5 dB/year) are generally problematic, much slower rates also may be deleterious for young patients, particularly those diagnosed with late disease. As a result, it is important to consider life expectancy, disease severity and vision-related quality of life based treatment targets to estimate future prognosis when evaluating whether a rate of glaucoma progression can be clinically relevant.

Keywords: Glaucoma; confocal scanning laser ophthalmoscopy; life expectancy; progression rates; quality of life; spectral domain optical coherence tomography; standard automated perimetry.

Conflict of interest statement

Declaration of Interest The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Figures

Figure 1

Incorporating severity of disease and life expectancy to identify clinically important rates of progression for an individual patient. The baseline visual field mean deviation (MD) is on the x-axis. The y-axis represents the linear rate of visual field loss that will result in advanced disease (Figure A) and blindness (Figure B). Advanced disease is defined as MD ≤ -12dB in Figure A, while Figure B uses an MD ≤ -22dB to represent statutory blindness. By estimating the patients remaining life expectancy, a critical rate of visual field loss to avoid can be defined. Each colored line corresponds to a different life expectancy (Life Exp) remaining.