The Normal Age-Corrected and Reaction Time–Corrected Isopter Derived by Semi-automated Kinetic Perimetry
Received 23 June 2006; accepted 13 September 2006. published online 01 March 2007.
Purpose
To determine the increase in isopter extent, resulting from the measurement of, and correction for, individual reaction time (RT; the latency between stimulus presentation and individual patient response), derived under the standardized conditions of semi-automated kinetic perimetry (SKP), and to model the age- and RT-corrected normative isopter values for SKP applicable to any Goldmann stimulus combination.
Design
Cross-sectional observational study.
Participants
Eighty-three healthy participants aged 10 to 80 years (11–12 participants per decade of age).
Methods
One eye of each participant underwent SKP using the Octopus 101 perimeter (Haag-Streit, Koeniz, Switzerland). Four Goldmann stimulus combinations, III4e at 25°/second, III4e at 5°/second, I3e at 5°/second, and I2e at 2°/second, were presented centripetally (i.e., in a direction toward the center of the bowl) along the 8 cardinal meridia in random order. The local kinetic threshold (LKT) for each stimulus combination along each meridian was corrected for the angular distance traveled during the individual geometric mean RT and was modeled in terms of the covariables stimulus size, stimulus luminance, meridian, and age, and then presented in terms of a graphical reference plot.
Main Outcome Measures
The variation of the LKT with RT, stimulus combination, meridian, and age.
Results
The median of the individual geometric mean RTs initially decreased and then increased with increase in age and was greater for stimulus combinations producing small isopters compared with those generating large isopters. Reaction time–corrected LKTs were fitted optimally by a multiple regression model (R2 = 0.86). For large (≥size III) and intense (4e) stimuli, RT-corrected LKTs were independent of age and mainly were influenced by instrument- and facial anatomy-related characteristics. Reaction time–corrected LKTs, particularly for small (≤size II) stimuli, exhibited a clear age dependence above the age of 40 years particularly for reduced luminance stimuli (≤2e), with an approximate reduction in angular extent of 2° per decade for the I1e stimulus.
Conclusions
The development of a graphical reference plot with mean isopters and accompanying reference intervals for age- and RT-corrected SKP, applicable to any individual patient, should facilitate the evaluation of clinical data and the implementation of a computerized alternative to manual Goldmann kinetic perimetry.
1Department of Medical Biometry, University of Tuebingen, Tuebingen, Germany.
2Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany.
3Department of Ophthalmology and 1st Eye Hospital, Medical University, Lublin, Poland.
4Service d’Ophtalmologie, Hôpital de Villeneuve Saint Georges, Villeneuve Saint Georges, France.
5Cardiff School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
Correspondence to John M. Wild, PhD, Cardiff School of Optometry and Vision Sciences, Cardiff University, Redwood Building, King Edward VII Avenue, Cathays Park, Cardiff CF10 3NB, United Kingdom.
Manuscript no. 2006-688.
Supported by the European Commission, Brussels, Belgium (contract no. QLG5-CT-2001-60034 [KN]), and Haag-Streit, Koeniz, Switzerland (US).
Financial disclosure: Drs Paetzold and Schiefer, consultants to Haag-Streit; Dr Wild, honoraria from Carl Zeiss Meditec for lectures.
ABSTRACT