Welch Allyn Autorefractor Quick Reference Guide - Quick Reference Guide - Manual (Page 2)

Results
Reliability Number indicates the number of good readings
obtained and their consistency, based on a 1 to 9 scale (higher
numbers are better).
• >6 is typically acceptable
✩
• 5 is marginal / repeat the test if possible
• <4 is poor / repetition of the test is necessary
✩
If the patient did not appear to fixate on the unit during data acquisition, repeat the test.
S is the sphere, or power of the eye measured in diopters. Negative numbers indicate myopia ( near-sightedness ), positive
numbers indicate hyperopia ( far-sightedness ).
C is the cylinder, a measure of astigmatism, or irregular focus of the eye.
D is the difference in the mean spherical power between the two eyes (displayed in child mode only).
* An asterisk on a reading in child mode indicates the reading is in the referral range for a pre-schooler.
A +9.9 or -9.9 indicates a reading outside the unit’s measurement range.
Referral Criteria
Readings outside the normal limits should be confirmed prior to referral.
It is recommended that referral criteria be agreed upon between you and the eye care specialist receiving your referrals.
Approximate Relationship of Sphere to Visual Acuity
✭✭
Ages 5-15
Charging
• A charged unit can test patients for approximately 3 hours (continuous use).
• To charge, firmly place the unit into the stand.
• With 15 minutes of on-time remaining, the low-battery indicator will begin to flash on the display. When low-battery
indicator is steady, battery must be recharged.
Part Number 140357-2 Rev. G
Results
Reliability Number indicates the number of good readings
obtained and their consistency, based on a 1 to 9 scale (higher
numbers are better).
• >6 is typically acceptable
✩
• 5 is marginal / repeat the test if possible
• <4 is poor / repetition of the test is necessary
✩
If the patient did not appear to fixate on the unit during data acquisition, repeat the test.
S is the sphere, or power of the eye measured in diopters. Negative numbers indicate myopia ( near-sightedness ), positive
numbers indicate hyperopia ( far-sightedness ).
C is the cylinder, a measure of astigmatism, or irregular focus of the eye.
D is the difference in the mean spherical power between the two eyes (displayed in child mode only).
* An asterisk on a reading in child mode indicates the reading is in the referral range for a pre-schooler.
A +9.9 or -9.9 indicates a reading outside the unit’s measurement range.
Referral Criteria
Readings outside the normal limits should be confirmed prior to referral.
It is recommended that referral criteria be agreed upon between you and the eye care specialist receiving your referrals.
Approximate Relationship of Sphere to Visual Acuity
✭✭
Ages 5-15
Charging
• A charged unit can test patients for approximately 3 hours (continuous use).
• To charge, firmly place the unit into the stand.
• With 15 minutes of on-time remaining, the low-battery indicator will begin to flash on the display. When low-battery
indicator is steady, battery must be recharged.
Part Number 140357-2 Rev. G
Negative (-)
Diopters
Myopia
(Near-Sightedness)
Positive (+)
Diopters
Hyperopia
(Far-Sightedness)
✭✭ ✭✭ ✭✭ ✭✭
0.0 20/20 0.0 20/20
-0.5 20/30-40 +1.0 20/20
-0.8 20/50 +2.0 20/20
-1.0 20/60 +3.0 20/25
-1.25 20/70 +3.25 20/30
-1.75 20/100 +3.75 20/40
-2.0 20/200 +4.0 20/40-50
-3.0 20/285 +4.3 20/50
-4.0 20/420 +5.0 20/70
-5.0 20/565
Sphere
Cylinder
Difference
Reliability
Number
Child/Adult
Mode
6 Months 3-5 years*
Sphere < -2.0 or > +3.5 < -1.0 or > +2.0
Cylinder ------- > 1.0
Difference >1.5 >1.0
1.5 0.5 1.0 0
1.5 0.5 1.0 0
+2.5 +1.5 -0.5 +0.5 -1.5 +2.0 +1.0 -1.0 0
Within Normal Limits
Outside Normal Limits
Negative (-)
Diopters
Myopia
(Near-Sightedness)
Positive (+)
Diopters
Hyperopia
(Far-Sightedness)
✭ ✭ ✭ ✭✭ ✭ ✭ ✭
0.0 20/20 0.0 20/20
-0.5 20/30-40 +1.0 20/20
-0.8 20/50 +2.0 20/20
-1.0 20/60 +3.0 20/25
-1.25 20/70 +3.25 20/30
-1.75 20/100 +3.75 20/40
-2.0 20/200 +4.0 20/40-50
-3.0 20/285 +4.3 20/50
-4.0 20/420 +5.0 20/70
-5.0 20/565
Sphere
Cylinder
Difference
Reliability
Number
Child/Adult
Mode
6 Months 3-5 years*
Sphere < -2.0 or > +3.5 < -1.0 or > +2.0
Cylinder ------- > 1.0
Difference >1.5 >1.0
1.5 0.5 1.0 0
1.5 0.5 1.0 0
+2.5 +1.5 -0.5 +0.5 -1.5 +2.0 +1.0 -1.0 0
Within Normal Limits
Outside Normal Limits