Influence of stage of glaucoma, age and examination time on reliability parameters in computed perimetry with Dicon TKS 4000.
OBJECTIVE
To evaluate the influence of glaucoma stage, age, and examination time on reliability parameters in computed perimetry with DICON TKS 4000.


METHODS
A total of 370 eyes of glaucoma patients were examined in random order with program 9 (30 degrees Threshold grid). They were allocated to 5 groups according to the visual field changes: no changes (112 eyes); mild changes (132 eyes); moderate changes (62 eyes); severe changes (44 eyes); end stage changes (20 eyes). The reliability of each examination was assessed by the rate of false positive responses (FP), fixation losses (FL), and the number of presentations (PR).


RESULTS
Fixation losses > or = 20% were observed in 60.8% of the examined eyes. Such a rate of FL occurred more frequently in the initial stages of glaucoma--75% in group 1 vs 10% in group 5. There was a moderate negative correlation between the rate of FL and the stage of glaucoma (r = -0.31, p < 0.001). There was a negative correlation between the examination time and the rate of FL (r = -0.35, p < 0.001). No correlation was found between the age of patients and FL. There was a slight correlation between the stage of glaucoma and FP (r = 0.14, p < 0.01), as well as between examination time and FP (r = 0.28, p < 0.001). There was no correlation between age and FP. The mean examination time for the whole study sample was 9.0 +/- 2.5 min. It correlated positively with PR (r = 0.96) and the stage of disease (r = 0.80).


CONCLUSIONS
FP, FL and PR are dependent on the stage of glaucoma and examination time. The lower frequency of FL in severe stages of glaucoma can be accounted for by the kinetic fixation and the procedure for testing FL (projecting a stimulus in the blind spot).
Konareva-Kostianeva
M
M
Department of Ophthalmology, Higher Medical Institute, Plovdiv, Bulgaria.
Atanassov
M
M
D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005901:Glaucoma / Q000175:diagnosis*; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D058609:Visual Field Tests / Q000295:instrumentation*