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Binocular function of patients with retinitis pigmentosa
International Congress Series 1282 (2005) 564 – 567
www.ics-elsevier.com
Binocular function of patients with retinitis pigmentosa Hiromi Hayashi*, Kenji Yanashima National Rehabilitation Center for the disabled, Namiki4-1 Tokorozawa City, Saitama, Japan
Abstract. Twenty-two of 32 RP patients visiting our low vision clinic between years 2002 and 2004 were assessed for binocular function. Titmus stereo test (T.S.T) and red-green stereo test was used to investigate binocular function for near distance and synoptophore for far distance. The patients with more than 0.1 logMAR vision were able to keep sufficient binocular vision for near distance, while those with less than 0.3 logMAR vision had suppression with the red-green stereo test or T.S.T and was inclined to have vertical deviation by synoptophore. Binocular vision of RP patients was reduced with decrease in visual acuity and loss of visual field. Patients with low visual acuity were inclined to have monovision and diplopia. However, vertical deviation was not found in patients with residual peripheral visual field regardless of visual acuity. D 2005 Elsevier B.V. All rights reserved. Keywords: Retinitis pigmentosa; Binocular function
1. Introduction Most patients with retinitis pigmentosa (RP) are able to keep efficient vision with 108 of central visual field intact in its early stage. Some patients, however, complain of double vision as peripheral field, including the Panum’s fusional area become diminished. These complaints are also associated with decrease in visual acuity. The aim of this study is: (1) to investigate binocular function of RP patients with diminished visual fields, (2) to determine the relationship between visual acuity and binocular function of RP patients. 2. Material and methods RP patients (female 16, male 18) visiting our low vision clinic between years 2002 and 2004 were assessed for binocular function, which include the head-tilting test, eye * Corresponding author. Tel.: +81 42 995 3100; fax: +81 42 996 2034. E-mail address: [email protected] (H. Hayashi). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.05.203
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
565
logMAR
1.6 1.2
Good Binocular Function Poor
0.8 0.4 0 10
30
50
70
age
Fig. 1. Visual acuity and age of the subjects, n = 34.
movement, and dominant eye test. All patients had sufficient refractive correction. Fig. 1 shows the visual acuity and age distribution. Titmus stereo test (T.S.T) and red-green stereo test were used to investigate binocular function for near distance and synoptophore for far distance. Cover test was used to check whether suppression and strabismus were present in a daily condition. We also performed a red-filter test with prism to determine the deviation. Twenty-two patients were examined using all of the above tests.
3. Results Table 1 shows binocular function of RP patients with constricted visual fields. Table 2 shows the result for the patients with peripheral visual field. RP patients with more than 0.1logMAR vision Table 1 Binocular function of the RP patients with tunnel vision
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
M/F
Age
logMAR V.A.
VF (degree)
Red-green test
T.S.T
F F F F M M F M F M M M F M F M F
50 39 45 47 54 30 68 56 33 72 45 58 31 55 68 43 49
0 0 0 0 0 0 0.1 0.1 0.2 0.2 0.2 0.3 0.4 0.4 0.5 0.7 0.7
10 15 7 15 12 11 10 9 8 15 15 3 30 5 5 8 8
b b b b b b b b b b L mono
80 s 50 s 50 s 40 s 80 s 40 s 40 s 200 s 40 s L mono L mono R mono 40 s
b R mono L mono double
L mono 400 s L mono
Synopto H 10 4 0 0.5 3 0 1 5 1 4 3 1 0 0 6 5 9
Synopto V 2 0 0.5 0.5 0 1 1 4 0 3 2 3 0 2 0.5 1 2
566
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
Table 2 Binocular function of the RP patients with peripheral visual field
1 2 3 4 5
M/F
Age
logMAR V.A.
VF (degree)
Red-green test
T.S.T
M M F M F
23 56 57 33 57
0 0.4 0.4 0.5 0.5
15 3 8 3 30
b
140 s R mono 3000 s L mono 200 s
L mono R mono
Synopto H 8 5 0 0 0
Synopto V 0 0 0 0 0
were able to keep sufficient binocular vision for near distance, while those with less than 0.3 logMAR vision had suppression with the red-green stereo test or T.S.T and was inclined to have vertical deviation by synoptophore (Fig. 2). Vertical deviation was not found in patients with residual peripheral visual field regardless of visual acuity.
4. Discussion Red-green test and T.S.T are performed under daily conditions of viewing, hence many patients attempt to keep their fusion-obtained binocular function by shifting eye position. The complaint of diplopia suggests that they have binocular vision which they use to consciously control diplopia by adopting a compensatory head posture [1]. Divergence can be measured with synoptophore, which is performed under a set condition, as opposed to red-green test and T.S.T. In order to understand the relationship between deviation and binocular function, we tried to quantify deviation within a narrow fusional area. Patients with constricted visual fields experience diplopia which is greatest at far distance rather than near. There may also be some cases with no diplopia because of decreased sensitivity of residual visual field. Some patients especially complain of difficulties with vertical diplopia [2]. In such cases, occlusion is the simplest method to manage diplopia. Vertical deviation however
(a)
(b)
20˚up −13
R/ 5
−13
R/ 3
cent er
−13
(degree)
20˚Down
R fix
Fig. 2. (a) Patient with constricted visual field adopting a compensatory chin-up to maintain single vision to reduce vertical deviation. (b) The vertical deviations by synoptophore.
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
567
Vertical (degree)
4
2
0 Horizontal
−5
0
+5
+10
(degree)
Good binocular function
poor
Fig. 3. The result of horizontal/vertical deviation by synoptophore. In the group of good binocular function, most of them have less than 18 in vertical deviation even though varied from 8 to +10 in horizontal.
was not found in patients with residual peripheral visual field regardless of visual acuity (Fig. 3). 5. Conclusion Binocular vision of RP patients was reduced with decreased visual acuity and loss of visual field. Patients with low visual acuity were inclined to have monovision and diplopia. Red-green test and T.S.T have the advantage of being performed in a free space. Sensory testing however can be difficult in patients with constricted visual field. In such cases, synoptophore with a set examination environment is preferred. Poor visual function is not a reason for not investigating binocular vision. We should recognize the patient’s visual function for orientation and mobility. References [1] Bruce Evans, Sandip Dosh, Binocular Vision and Orthoptics, Butterworth-Heinemann, Eleanor, 2001. [2] Hiromi Hayashi, The Effectiveness of Gradient-Tinted Absorptive Lenses, The Association of Sensory Substitution, 2003.
www.ics-elsevier.com
Binocular function of patients with retinitis pigmentosa Hiromi Hayashi*, Kenji Yanashima National Rehabilitation Center for the disabled, Namiki4-1 Tokorozawa City, Saitama, Japan
Abstract. Twenty-two of 32 RP patients visiting our low vision clinic between years 2002 and 2004 were assessed for binocular function. Titmus stereo test (T.S.T) and red-green stereo test was used to investigate binocular function for near distance and synoptophore for far distance. The patients with more than 0.1 logMAR vision were able to keep sufficient binocular vision for near distance, while those with less than 0.3 logMAR vision had suppression with the red-green stereo test or T.S.T and was inclined to have vertical deviation by synoptophore. Binocular vision of RP patients was reduced with decrease in visual acuity and loss of visual field. Patients with low visual acuity were inclined to have monovision and diplopia. However, vertical deviation was not found in patients with residual peripheral visual field regardless of visual acuity. D 2005 Elsevier B.V. All rights reserved. Keywords: Retinitis pigmentosa; Binocular function
1. Introduction Most patients with retinitis pigmentosa (RP) are able to keep efficient vision with 108 of central visual field intact in its early stage. Some patients, however, complain of double vision as peripheral field, including the Panum’s fusional area become diminished. These complaints are also associated with decrease in visual acuity. The aim of this study is: (1) to investigate binocular function of RP patients with diminished visual fields, (2) to determine the relationship between visual acuity and binocular function of RP patients. 2. Material and methods RP patients (female 16, male 18) visiting our low vision clinic between years 2002 and 2004 were assessed for binocular function, which include the head-tilting test, eye * Corresponding author. Tel.: +81 42 995 3100; fax: +81 42 996 2034. E-mail address: [email protected] (H. Hayashi). 0531-5131/ D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.ics.2005.05.203
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
565
logMAR
1.6 1.2
Good Binocular Function Poor
0.8 0.4 0 10
30
50
70
age
Fig. 1. Visual acuity and age of the subjects, n = 34.
movement, and dominant eye test. All patients had sufficient refractive correction. Fig. 1 shows the visual acuity and age distribution. Titmus stereo test (T.S.T) and red-green stereo test were used to investigate binocular function for near distance and synoptophore for far distance. Cover test was used to check whether suppression and strabismus were present in a daily condition. We also performed a red-filter test with prism to determine the deviation. Twenty-two patients were examined using all of the above tests.
3. Results Table 1 shows binocular function of RP patients with constricted visual fields. Table 2 shows the result for the patients with peripheral visual field. RP patients with more than 0.1logMAR vision Table 1 Binocular function of the RP patients with tunnel vision
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
M/F
Age
logMAR V.A.
VF (degree)
Red-green test
T.S.T
F F F F M M F M F M M M F M F M F
50 39 45 47 54 30 68 56 33 72 45 58 31 55 68 43 49
0 0 0 0 0 0 0.1 0.1 0.2 0.2 0.2 0.3 0.4 0.4 0.5 0.7 0.7
10 15 7 15 12 11 10 9 8 15 15 3 30 5 5 8 8
b b b b b b b b b b L mono
80 s 50 s 50 s 40 s 80 s 40 s 40 s 200 s 40 s L mono L mono R mono 40 s
b R mono L mono double
L mono 400 s L mono
Synopto H 10 4 0 0.5 3 0 1 5 1 4 3 1 0 0 6 5 9
Synopto V 2 0 0.5 0.5 0 1 1 4 0 3 2 3 0 2 0.5 1 2
566
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
Table 2 Binocular function of the RP patients with peripheral visual field
1 2 3 4 5
M/F
Age
logMAR V.A.
VF (degree)
Red-green test
T.S.T
M M F M F
23 56 57 33 57
0 0.4 0.4 0.5 0.5
15 3 8 3 30
b
140 s R mono 3000 s L mono 200 s
L mono R mono
Synopto H 8 5 0 0 0
Synopto V 0 0 0 0 0
were able to keep sufficient binocular vision for near distance, while those with less than 0.3 logMAR vision had suppression with the red-green stereo test or T.S.T and was inclined to have vertical deviation by synoptophore (Fig. 2). Vertical deviation was not found in patients with residual peripheral visual field regardless of visual acuity.
4. Discussion Red-green test and T.S.T are performed under daily conditions of viewing, hence many patients attempt to keep their fusion-obtained binocular function by shifting eye position. The complaint of diplopia suggests that they have binocular vision which they use to consciously control diplopia by adopting a compensatory head posture [1]. Divergence can be measured with synoptophore, which is performed under a set condition, as opposed to red-green test and T.S.T. In order to understand the relationship between deviation and binocular function, we tried to quantify deviation within a narrow fusional area. Patients with constricted visual fields experience diplopia which is greatest at far distance rather than near. There may also be some cases with no diplopia because of decreased sensitivity of residual visual field. Some patients especially complain of difficulties with vertical diplopia [2]. In such cases, occlusion is the simplest method to manage diplopia. Vertical deviation however
(a)
(b)
20˚up −13
R/ 5
−13
R/ 3
cent er
−13
(degree)
20˚Down
R fix
Fig. 2. (a) Patient with constricted visual field adopting a compensatory chin-up to maintain single vision to reduce vertical deviation. (b) The vertical deviations by synoptophore.
H. Hayashi, K. Yanashima / International Congress Series 1282 (2005) 564–567
567
Vertical (degree)
4
2
0 Horizontal
−5
0
+5
+10
(degree)
Good binocular function
poor
Fig. 3. The result of horizontal/vertical deviation by synoptophore. In the group of good binocular function, most of them have less than 18 in vertical deviation even though varied from 8 to +10 in horizontal.
was not found in patients with residual peripheral visual field regardless of visual acuity (Fig. 3). 5. Conclusion Binocular vision of RP patients was reduced with decreased visual acuity and loss of visual field. Patients with low visual acuity were inclined to have monovision and diplopia. Red-green test and T.S.T have the advantage of being performed in a free space. Sensory testing however can be difficult in patients with constricted visual field. In such cases, synoptophore with a set examination environment is preferred. Poor visual function is not a reason for not investigating binocular vision. We should recognize the patient’s visual function for orientation and mobility. References [1] Bruce Evans, Sandip Dosh, Binocular Vision and Orthoptics, Butterworth-Heinemann, Eleanor, 2001. [2] Hiromi Hayashi, The Effectiveness of Gradient-Tinted Absorptive Lenses, The Association of Sensory Substitution, 2003.