Practical recommendations for measuring rates of visual field change in glaucoma
Chauhan BC, Garway-Heath DF, Goñi FJ, Rossetti L, Bengtsson B, Viswanathan AC, Heijl A.
Department of Ophthalmology and Visual Sciences, Dalhousie University, 2nd Floor Centennial Building, Queen Elizabeth II Health Sciences Centre, Halifax, Canada.
To date, there has been a lack of evidence-based guidance on the frequency of visual field examinations required to identify clinically meaningful rates of change in glaucoma. The objective of this perspective is to provide practical recommendations for this purpose. The primary emphasis is on the period of time and number of examinations required to measure various rates of change in mean deviation (MD) with adequate statistical power. Empirical data were used to obtain variability estimates of MD while statistical modeling techniques derived the required time periods to detect change with various degrees of visual field variability. We provide the frequency of examinations per year required to detect different amounts of change in 2, 3 and 5 years. For instance, three examinations per year are required to identify an overall change in MD of 4 dB over 2 years in a patient with average visual field variability. Recommendations on other issues such as examination type, strategy, and quality are also made.
Br J Ophthalmol 2008;92:569-573
Kommentar
Artiklen giver evidensbaserede rekommandationer for, hvor hyppigt perimetri bør foretages, hvis man inden for en rimelig tidsperiode skal kunne diagnosticere progression hos en glaukompatient.
- Diagnostik af statistisk signifikant progression afhænger af variabilitet af synsfelter samt antallet af synsfelter.
- Med 3 synsfelter pr. år vil hurtig progression (-2 dB/år) kunne verificeres i løbet af 2 år og langsom progression (-0.5 dB/år) i løbet af 4 år hos patienter med moderat variabilitet af synsfelter.
Baseret på ovenstående anbefales 6 synsfelter de første 2 år som basis (progressionsprofil) for fortsat follow-up og behandling.
S. Krag