Transcript Optec ® 6500

Department of ophthalmology,
Yonsei University, college of medicine
Tae-im Kim, Sang Woo Kim, Byung Jin Ha,
Eung Kweon Kim
Introduction
Vistech VCTS (Vision Contrast Test System)® 6500
- under normal room lighting (30-60 ft L)
- recommanded distance : Far - 10 feet (3m)
- measure with best optical correction
contrast changes:
Average in 0.25 log unit step
5 different spatial frequencies
(1.5, 3, 6, 12, 18 cpd)
each stimulus has ±15° tilted
sine wave
criterion dependent method :
right, left, up and blank
Introduction
Optec® 6500
Stero Optical co., Inc. Chicago, IL, USA
Microprocessor-controlled and continually calibrated light levels
; Target illumination with 3.0 cd/m² for night or 85 cd/m² for day
; Compliance with the ANSI
Contrast sensitivity slide package
; F.A.C.T® sine wave or C.A.T letter
Near and Far testing capability
Binocular glare testing
Eyeview® software
Data base for research
Introduction
F.A.C.T (Functional Acuity Contrast Test)® 201
- consists of the circular stimuli in 5 rows and 8 columns
- recommended distance : Far - 10 feet (3m)
- measure with best optical correction
contrast changes:
Average in 0.15 log unit step
5 different spatial frequencies
(1.5, 3, 6, 12, 18 cpd)
Larger patch size than VCTS
: 1.7 degrees
each stimulus has ±15°
tilted sine wave
3 Alternative forced choice
: right, left, up
Purpose
To investigate the repeatability and sensitivity of
Optec® 6500 for contrast sensitivity measurement,
comparing with commonly used Vistec VCTS 6500
chart in normal, healthy subjects
Methods
Subjects
 40 eyes of young healthy volunteers, (14 male and 6 female)
(total)

age 27.5 (26 ~ 34 years old)

BCVA of all subjects; 0.8 or better

Excluding criteria
- any ocular pathology (cataract, glaucoma, retinal disease etc)
- any previous ocular surgery
- any neurological problem
- any systemic disease
- insufficient mental ability to perform the test
- physical disability which make it difficult to perform the test
Methods
Procedure
measurements done twice with1 week interval with optimal refractive
correction and natural pupil
1. Measurements of CST with Vistech VCTS 6500 ( Group 1 )
under room luminance (≒120 cd/m2), working distance of 3m
2. Measurements of CST with Optec 6500 ( Group 2 )
under continually controlled luminance : 85 cd/m2 using F.A.C.T 201 chart
Data and Statistics
1. Numericalized CST values, using conversion chart
2. Contrast sensitivity were compared at all frequencies
Sensitivity : T test, Repeatability : Bland and Altman plot
Coefficient of Repeatibility (COR)
3. STSS v 10.1 for windows (SPSS Inc., Chicago, IL, USA)
Results
CST of VCTS and Optec 6500 (mean, 95% CI)
Contrast sensitivity
250
200
150
u
VCTS
v cst
n Optec
fact
100
Range of VCTS
Range of Optec
50
0
0
5
10
15
20
Spatial Frequency (cpd)
* T test, p<0.001, n=80 for each frequency
Results
Table. Mean and Standard deviation of CST between test and retest
Vistech
Optec® 6500
Test (Mean (SD))
Retest (Mean (SD))
1.5 cpd
74.13 (19.96)
75.00 (24.49)
3.0 cpd
126.86 (48.28)
140.85 (47.58)
6.0 cpd
162.13 (49.82)
173.25 (43.54)
12 cpd
135.53 (33.48)
129.98 (28.39)
18 cpd
62.50 (15.61)
60.90 (18.69)
1.5 cpd
45.3 (20.86)
47.6 (21.15)
3.0 cpd
90.73 (48.01)
87.60 (29.09)
6.0 cpd
100.70 (47.56)
92.78 (41.97)
12 cpd
49.23 (21.17)
47.73 (22.90)
18 cpd
19.28 (12.51)
15.60 (9.41)
* n=40
Results
 Maximal contrast sensitivity was observed at 6 cpd and was
significant higher if compared to 1.5, 12 and 18 cpd in both test
using two different machine.
 The distributions of the score of contrast sensitivity test are
similar in both test.
 The scores of contrast sensitivity of Optec 6500 are relatively
low.
 The discrepancy of repeated test is also less prominent in
Optec 6500.
Discussion
 Contrast sensitivity (CS) describes the ability to distinguish
differences in luminance
 There are several commercially available clinical testers
: The Vistech CS chart series are popular
but, reported not to warrant repeatability in several papers
 Optec® 6500 Vision Tester
: based on the Functional Acuity Contrast Test (FACT)
multifunctional instrument
measurement of visual acuity, contrast sensitivity, disability glare
as well as stereo- and color vision.
Conclusions
1. Sensitivity of contrast sensitivity test with Vistec VCTS is better
than that Optec 6500 in normal eye.
2. Testing results using Optec 6500 improved accuracy in analysis
of contrast sensitivity with narrow range score, accurate CST,
and adopting strict 3 alternative forced choice method for
analysis
3. Repeatability of each test using Optec 6500 is better than that
of Vistec VCST
4.
Measurement of contrast sensitivity with Optec 6500 might be
comparable or better in studies to compare the quality of
implanted lenses or refractive surgery outcome than Vistec
VCTS