Abstract
Purpose: :
to analyze the possibility of predicting the rate of glaucoma damage progression and its acceleration over time periods ranging from 5 to 25 years using an original algorithm (Glaucoma Damage Probability Trend, GDPT©) based on the Brusini’s Glaucoma Staging System 2© (GSS2) and inserted into the Glaucoma Management System© (GMS).
Methods: :
n = 24 eyes of 24 glaucoma patients (average age 75, age range 58-84) who were studied over an average period of 10.8 years (from 8 to 20 years) with annual visual field tests (Humphrey 24/2, either full threshold or SITA) with an average of 11.8 tests per patient. To calculate the probability of progression, the patient follow-up was divided into two parts; the first part (5 years with a minimum of 5 visual field tests) was used to calculate the progression rate of each patien. The GDPT algorithm runs on visual field indexes (MD and PSD for Humphrey, MS and LV for Octopus) that the observer must input manually in the system. Thanks to the GSS2, data collected from both analyzers can be used to estimate progression rate in the individual patient. GDPT was used to predict the progress of the disease and the nature of the progression, comparing the theoretical results obtained through the algorithm with the real ones which were verifiable from the second part of the patient follow-up.
Results: :
at the end of the follow up, the actual GSS stage was 3,06 (1,44 st.dev). The predicted GSS value was slightly lower, being 2,81 (1,63 st.dev). The mean square deviation based on was 0.25 of GSS2 stage.
Conclusions: :
The GDPT© algorithm offers a good estimate of the possible progression rate of visual field damage in glaucoma
Keywords: visual fields • clinical (human) or epidemiologic studies: systems/equipment/techniques