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Atypical Findings in Vectograph Stereotesting: Case Presentations
ATYPICAL FINDINGS IN VECTOGRAPH STEREOTESTING: CASE PRESENTATIONS VICKI
K. ROSZKA, BGS, CO, DEARBORN, MICHIGAN
THE purpose of this paper is to report case findings using the American Optical Project-O-Chart Child Slide III, #11246 (Fig 1), which may be used as a quick screening device for gross suppression. This slide provides a series of monocular-acuity tests to be used under binocular viewing conditions; thus, there are a number of tests for sensory evaluation. The manufacturer suggests using the cross target to test for fixation disparity. This test shows two vertical arrows pointing toward a circle and two horizontal lines on either side of the circle (Fig 2). When the patient wears the Polaroid spectacles, the lower arrow and the left line are seen by the left eye only and the upper arrow and the right line are seen by the right eye only.
The stereo acuity test has five different figures which a child must identify as being displaced toward him when observed through the Polaroid spectacles (Fig 3). The manufacturer provides the following description: This is a stereotest wherein objects common to most young children's experience are seen displaced toward the patient by a stereo-disparity of four minutes of arc. The triangle, cross, and circle are displaced Submitted for publication June
n,
1979.
Presented at The 1978 Midwestern Regional Meeting of the American Assocaition of Certified Orthoptists, Omaha, Neb, May 16-18. Reprint requests to 15212 Michigan Ave, Dearborn, MI 48126 (Me Roszka, c/o Dearborn Ear, Eye, Nose & Throat Clinic).
COT
forward by disparities of 3, 2, and 1 minutes of arc respectively. The square, with no stereo-disparity,"resides" in the plane of the screen.
An unfortunate feature of this test is the way in which the figures are displayed. It is one of direct counterclockwise regression beginning with the star, closest to the individual, and finishing with the square, which '''resides' in the plane of the screen," obviously a less-than-random display of test figures. However, the clinician may, as I did, introduce questions that can randomize the way in which the patient responds to the figures. Rather than consistently asking the patient to compare one figure to the other four figures, questions regarding the proximity of various combinations of two or more figures may be asked. Less sophisticated patients require the less complex combination of comparing only one figure to one other figure. A consistent finding in patients who have microtropia is said to be gross or defective stereoacuity.l Other consistent findings may include amblyopia, anomalous retinal correspondence, a relative scotoma of the fovea, or fixation spot of the deviated eye with normal or nearnormal peripheral fusion with amplitudes. Hadley2 states that individuals with monofixation syndrome have less-than-perfect stereopsis, as detected by ~e. Wirt stereotest. Their stereoacUlty IS not better than 67 seconds of arc. This area was investigated by Helveston and Von Noordern3 in 1967.
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Fig 2.
It is well known that findings will vary depending on the test used. Some tests yield more consistent results than others. Finding appropriate tests that yield accurate and reliable information is essential to the clinician.
3me III ..
+
Hill et aI' found that 12 of 40 patients who had microtropia were able to achieve better than 80 seconds of arc on the Titmus stereotest at near fixation. However, some were able to achieve 40 seconds of arc. The maximum response at distance was 228 seconds of arc on the synoptophore. These and other researchers l - 5 have told us to expect the same, that is, gross or defective stereoacuity with anomalous peripheral fusion.
W E :I
•
]
• • •• • ••• 1
OPHTH AAO
The literature leads orthoptists to expect defective stereo acuity as
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J
····· 1
..... ..... ....
•••••••• .
Fig 1.
Fig 3.
VOLUME 86 DECEMBER 1979
VECTOGRAPH STEREOTESTING
substantiated by studies using the Wirt near stereotest. Some patients who are not fixating bifoveally, however, demonstrate perfect scores on the distance stereotest mentioned above. The following case studies are evidence for this find~ ing.
CASE REPORTS CASE I.-A 7-year-old girl had been followed for strabismic amblyopia of the right eye since age 4. Her most recent cycloplegic refraction revealed OD = +7.00+0.75x180°, OS = +6.75+0.75X172°. Her visual acuity with correction was 20/20 OD and 20/20 OS at distance, 20/50 and 20/40 OS at near. She exhibited a 2~ RET at distance and M RET at near. On the Titmus stereotest she demonstrated a positive fly response, 3/3 animals, and 3/9 circles or 200 seconds of arc stereoacuity. She gave the fusion response while esotropic on the Worth Four-Dot test it distance and near. Her response with the Bagolini striated glasses was also positive for anomalous retinal correspondence. On the distance vectograph child's slide stereotest, she responded correctly to 5/5 figures or 60 seconds of arc, yet claimed suppression of the right eye of the cross target for fixation disparity.
2145
COMMENT
On the basis of testing with the American Optical Child Slide III, the distance stereoacuity of these two patients was perfect; however, we know that they were not fixating bifoveally but were suppressing the right eye. We could consider this unexpected finding an indication of an element of the monofixation syndrome that has heretofore been overlooked. On the other hand, since we have contradictory information within the same slide, these findings could be an indication of a flaw in the test. Certainly two cases with similar findings are not enough to define a new entity, redefine an established one, or destroy the validity of the tests mentioned. These findings do, however, suggest that further investigation of a larger population may add definition to established entities or aid the clinician in deciding on which tests to rely for consistent and reliable information. ACKNOWLEDGMENTS
CASE 2.-A 9-year-old girl had been fol· lowed for strabismic amblyopia of the right eye since age 6. Her most recent cycloplegic refraction revealed OD = +0.50+ 1.00xBO°, OS = -0.12+0.50X94°. Her visual acuity with correction was 20/30 OD and 20/20 OS at distance, 20/50 OD and 20/25 OS at near. She exhibited a monofIxational phoria manifesting a 4~ RET, building up to a 14~ ET upon prolonged occlusion at distance, and 12~ ET at near. On the Titmus stereotest she demonstrated a positive fly response, 113 animals, but 0/9 circles or 400 seconds of arc stereoacuity. On the Worth Four-Dot test she claimed suppression of the right eye with RET at distance, and "fusion" at times, suppression of the right eye at other times, with RET at near. On the Bagolini striated glasses, her response was positive for anomalous retinal correspondence. On the distance stereo~st she reported correct responses on 5/5 figures or 60 seconds of arc and claimed suppression of the right eye on the cross target.
The author expresses appreciation to E. J. Beyst-Martonyi for her help in preparing this paper and to K. H. Meinert for the photographs.
REFERENCES 1. Burian HM, Von Noorden GK: Binocu· lar Vision and Ocular Motility. 1974, p 296. 2. Hadley R: Pediatric Ophthalmology. 1975, p 157. 3. Helveston EM, Von Noorden GK: Microtropia: A newly defined entity. Arch Oph· thalmol 78:272, 1967. 4. Hill M, Perry J, Wood ICJ: Stereoacuity in microtropia. Orthoptics: Past, Present, and Future. Miami, Symposia Specialists, 1976, pp 26-27. 5. Jampolsky A: Retinal correspondence in patients with small degree strabismus. Arch Ophthalmol 45:18, 1951.
K. ROSZKA, BGS, CO, DEARBORN, MICHIGAN
THE purpose of this paper is to report case findings using the American Optical Project-O-Chart Child Slide III, #11246 (Fig 1), which may be used as a quick screening device for gross suppression. This slide provides a series of monocular-acuity tests to be used under binocular viewing conditions; thus, there are a number of tests for sensory evaluation. The manufacturer suggests using the cross target to test for fixation disparity. This test shows two vertical arrows pointing toward a circle and two horizontal lines on either side of the circle (Fig 2). When the patient wears the Polaroid spectacles, the lower arrow and the left line are seen by the left eye only and the upper arrow and the right line are seen by the right eye only.
The stereo acuity test has five different figures which a child must identify as being displaced toward him when observed through the Polaroid spectacles (Fig 3). The manufacturer provides the following description: This is a stereotest wherein objects common to most young children's experience are seen displaced toward the patient by a stereo-disparity of four minutes of arc. The triangle, cross, and circle are displaced Submitted for publication June
n,
1979.
Presented at The 1978 Midwestern Regional Meeting of the American Assocaition of Certified Orthoptists, Omaha, Neb, May 16-18. Reprint requests to 15212 Michigan Ave, Dearborn, MI 48126 (Me Roszka, c/o Dearborn Ear, Eye, Nose & Throat Clinic).
COT
forward by disparities of 3, 2, and 1 minutes of arc respectively. The square, with no stereo-disparity,"resides" in the plane of the screen.
An unfortunate feature of this test is the way in which the figures are displayed. It is one of direct counterclockwise regression beginning with the star, closest to the individual, and finishing with the square, which '''resides' in the plane of the screen," obviously a less-than-random display of test figures. However, the clinician may, as I did, introduce questions that can randomize the way in which the patient responds to the figures. Rather than consistently asking the patient to compare one figure to the other four figures, questions regarding the proximity of various combinations of two or more figures may be asked. Less sophisticated patients require the less complex combination of comparing only one figure to one other figure. A consistent finding in patients who have microtropia is said to be gross or defective stereoacuity.l Other consistent findings may include amblyopia, anomalous retinal correspondence, a relative scotoma of the fovea, or fixation spot of the deviated eye with normal or nearnormal peripheral fusion with amplitudes. Hadley2 states that individuals with monofixation syndrome have less-than-perfect stereopsis, as detected by ~e. Wirt stereotest. Their stereoacUlty IS not better than 67 seconds of arc. This area was investigated by Helveston and Von Noordern3 in 1967.
2143
tI _E
VT(;KT K. ROSZKA
2144
..... ... .. ."'.....
..........
•
1
-0-
f
wm
~ j··!I··1
iI.EIIIS
• • • • ·~l • • • J ~....
mEW
ils
'·····1 I •••••••
~ ••• . ••• __ e _ _
•
!...: ••
0 t
Fig 2.
It is well known that findings will vary depending on the test used. Some tests yield more consistent results than others. Finding appropriate tests that yield accurate and reliable information is essential to the clinician.
3me III ..
+
Hill et aI' found that 12 of 40 patients who had microtropia were able to achieve better than 80 seconds of arc on the Titmus stereotest at near fixation. However, some were able to achieve 40 seconds of arc. The maximum response at distance was 228 seconds of arc on the synoptophore. These and other researchers l - 5 have told us to expect the same, that is, gross or defective stereoacuity with anomalous peripheral fusion.
W E :I
•
]
• • •• • ••• 1
OPHTH AAO
The literature leads orthoptists to expect defective stereo acuity as
J J
J
····· 1
..... ..... ....
•••••••• .
Fig 1.
Fig 3.
VOLUME 86 DECEMBER 1979
VECTOGRAPH STEREOTESTING
substantiated by studies using the Wirt near stereotest. Some patients who are not fixating bifoveally, however, demonstrate perfect scores on the distance stereotest mentioned above. The following case studies are evidence for this find~ ing.
CASE REPORTS CASE I.-A 7-year-old girl had been followed for strabismic amblyopia of the right eye since age 4. Her most recent cycloplegic refraction revealed OD = +7.00+0.75x180°, OS = +6.75+0.75X172°. Her visual acuity with correction was 20/20 OD and 20/20 OS at distance, 20/50 and 20/40 OS at near. She exhibited a 2~ RET at distance and M RET at near. On the Titmus stereotest she demonstrated a positive fly response, 3/3 animals, and 3/9 circles or 200 seconds of arc stereoacuity. She gave the fusion response while esotropic on the Worth Four-Dot test it distance and near. Her response with the Bagolini striated glasses was also positive for anomalous retinal correspondence. On the distance vectograph child's slide stereotest, she responded correctly to 5/5 figures or 60 seconds of arc, yet claimed suppression of the right eye of the cross target for fixation disparity.
2145
COMMENT
On the basis of testing with the American Optical Child Slide III, the distance stereoacuity of these two patients was perfect; however, we know that they were not fixating bifoveally but were suppressing the right eye. We could consider this unexpected finding an indication of an element of the monofixation syndrome that has heretofore been overlooked. On the other hand, since we have contradictory information within the same slide, these findings could be an indication of a flaw in the test. Certainly two cases with similar findings are not enough to define a new entity, redefine an established one, or destroy the validity of the tests mentioned. These findings do, however, suggest that further investigation of a larger population may add definition to established entities or aid the clinician in deciding on which tests to rely for consistent and reliable information. ACKNOWLEDGMENTS
CASE 2.-A 9-year-old girl had been fol· lowed for strabismic amblyopia of the right eye since age 6. Her most recent cycloplegic refraction revealed OD = +0.50+ 1.00xBO°, OS = -0.12+0.50X94°. Her visual acuity with correction was 20/30 OD and 20/20 OS at distance, 20/50 OD and 20/25 OS at near. She exhibited a monofIxational phoria manifesting a 4~ RET, building up to a 14~ ET upon prolonged occlusion at distance, and 12~ ET at near. On the Titmus stereotest she demonstrated a positive fly response, 113 animals, but 0/9 circles or 400 seconds of arc stereoacuity. On the Worth Four-Dot test she claimed suppression of the right eye with RET at distance, and "fusion" at times, suppression of the right eye at other times, with RET at near. On the Bagolini striated glasses, her response was positive for anomalous retinal correspondence. On the distance stereo~st she reported correct responses on 5/5 figures or 60 seconds of arc and claimed suppression of the right eye on the cross target.
The author expresses appreciation to E. J. Beyst-Martonyi for her help in preparing this paper and to K. H. Meinert for the photographs.
REFERENCES 1. Burian HM, Von Noorden GK: Binocu· lar Vision and Ocular Motility. 1974, p 296. 2. Hadley R: Pediatric Ophthalmology. 1975, p 157. 3. Helveston EM, Von Noorden GK: Microtropia: A newly defined entity. Arch Oph· thalmol 78:272, 1967. 4. Hill M, Perry J, Wood ICJ: Stereoacuity in microtropia. Orthoptics: Past, Present, and Future. Miami, Symposia Specialists, 1976, pp 26-27. 5. Jampolsky A: Retinal correspondence in patients with small degree strabismus. Arch Ophthalmol 45:18, 1951.