Journal of Neuro-Ophthalmology, June 1992, Volume 12, Issue 2

Color vision in dominant optic atrophy.

The color vision of seven patients with dominant optic atrophy in four different families was studied with the following color vision tests: the Standard Pseudoisochromatic Plates part 2, the Lanthony Tritan Album, the Velhagen Pflgertrident plates, and Farnsworth Panel D 15, the Farnsworth-Munsell 100 hue test, the Nagel anomaloscope, and the Besancon anomalometer. In the first family, the mother, one of the sons, and one of the grandsons were affected. The mother had a deutantritan defect; the son and the grandson both had an undefined red-green and a tritan defect. In the third family, the mother and the son were affected. Only the color vision of the son could be examined. He had a tritan defect. In the fourth family, the mother and the daughter were affected. Both had a deutan defect. In the diagnosis of dominant optic atrophy, it must be remembered that not only blue color vision defects occur, but that other kinds of defects are also possible.

loumal of Cll/ Ileal Ne'/ ro- ol'hthahnol" xy 12( 2): 98- 103, 1992. Color Vision in Dominant Optic Atrophy Maija I. Mantyjarvi, M. D., Klaus Nerdrum, M. D., and Kaija Tuppurainen, M. D. © 1992 Raven Press, Ltd., New York The color vision of seven patients with dominant optic atrophy in four different families was studied with the following color vision tests: the Standard Pseudoiso­chromatic Plates part 2, the Lanthony Tritan Album, the Velhagen Pflligertrident plates, and Farnsworth Panel D 15, the Farnsworth- Munsell 100 hue test, the Nagel anomaloscope, and the Besancon anomalometer. In the first family, the mother, one of the sons, and one of the grandsons were affected. The mother had a deutan­tritan defect; the son and the grandson both had an un­defined red- green and a tritan defect. In the second fam­ily, only one member was affected. He had an undefined red- green and a tritan defect. In the third family, the mother and the son were affected. Only the color vision of the son could be examined. He had a tritan defect. In the fourth family, the mother and the daughter were affected. Both had a deutan defect, In the diagnosis of dominant optic atrophy, it must be remembered that not only blue color vision defects occur, but that other kinds of defects are also possible. Key Words: Dominant optic atrophy- Color vision de­fects--- Color vision tests. From the Department of Ophthalmology, University Hospi­tal of Kuopio, Kuopio, Finland. This work was supported by the Finnish Eye Foundation. ~ ddresscorrespondence and reprint requests to Dr. Maija I. MantyJarvl,. Department of Ophthalmology, University Hospi­tal of KUOplO, P 0 B. 1777, 70211 Kuopio, Finland. 98 Dominant optic atrophy ( DOA) is a hereditary eye disease with the following features ( 1- 5): ( a) a decreased visual acuity, usually from 20/ 100 to 20/ 40, but better or worse acuities are possible; ( b) pallor of the optic disc, especially temporally; ( c) central, paracentral, or cecocentral visual field de­fects; ( d) normal electroretinogram ( ERG) but de­fective visual evoked potentials ( VEPs); ( e) onset at an early age, probably between 1 and 10 years; and ( f) a color vision defect. The color vision defect in DOA has been described predominantly as a tritan defect ( 3- 5). A patient with all the typical symptoms of DOA was recently examined at our clinic. However, her color vision defect was an acquired green defect. This finding was inconsistent with the diagnosis of DOA and led to a survey of the literature about color vision in DOA, as well as a closer analysis of the color vision in all of our seven DOA patients. PATIENTS AND METHODS In four families ( Fig. 1), seven patients with DOA and six of their relatives were examined. Medical records and reliable information about two other relatives were also available. The diagnosis of DOA was based on the history given by the patients; decreased visual acuity in both eyes; pale optic discs; central, paracentral, or cecocentral visual field defects; normal dark adap­tation; normal ERG, abnormal VEPs; and color vi­sion defect. The age, sex and visual acuities of the patients are shown in Table 1. In the color vision examination, the following seven tests were used: 1. the Standard Pseudoisochromatic Plates part 2 ( SPP2) ( 6) for red- green and blue defects 2. the Velhagen Pfliigertrident test ( 7) for red­green defects 3. the Lanthony Tritan Album ( 8) for blue de­fects COLOR VISION IN DOMINANT OPTIC ATROPHY 99 4. the Farnsworth Panel 0 15 ( Panel 0 15) cap test ( 9) for red, green, and blue defects 5. the Farnsworth- Munsell 100 hue ( FM100) cap test ( 10) for red, green, and blue defects; the testee has a color vision defect if the error score is above the age- relevant upper limit ( 11) and/ or an axis is found in the result figure ( 12) 6. the Nagel anomaloscope ( Schmidt & Ha­ensch, Berlin FRG) for red and green color vision defects. This examination is based on the Rayleigh equation: green and red spectral colors are mixed, and the mixture is compared to monochromatic yellow. The scale units extend from 0 ( green) to 73 ( red). The examination with the anomaloscope was made according to the principles described by Birch ( 13) and Linksz, referred to by Birch et al. ( 14). The anomalous quotients ( AQ) from 0.7 to 1.3 and matching ranges ( MR) from 0 to 7 scale units were considered normal ( 14). 7. the Besancon anomalometer ( Statice, Besan­con, France) for red, green ( Rayleigh equation), and blue ( Moreland equation) color vision. In the present study, only the blue equation of the anom­alometer was used. In the equation, blue and green spectral colors are mixed in different propor­tions and compared to a cyan blue color. The scale units extend from 0 ( blue) to 100 ( green). AQs from 0.7 to 1.4 and MRs from 0 to 10 scale units were considered normal ( 15- 17). RESULTS Case 1 This 62- year- old woman ( Family A, II- 4) had suf­fered from poor vision since early childhood. Her father ( A, I- I), now dead, had also had poor vi­sion, but his medical record did not confirm the diagnosis of DOA. The visual acuity of the patient was 20/ 200 in both eyes. She saw none of the num­bers in the SPP2 test. In the FM 100 test, she had almost an achromatic result figure and an error score of 1234 in the right and 1065 in the left eye with no axis. She was not completely achromatic, because in the Nagel anomaloscope her response was deuteranopic, not achromatic ( 18). Also, she had not shown an achromatic response in an ear­lier Sloan achromatopsia test. In the Besancon anomalometer with a blue equation, she showed a tritanomalic response in the right eye and almost a tritanopic response in the left eye. This 4- year- old boy ( Family A, IV- I) had a visual acuity of 20/ 200 in both eyes. He was first sent to our strabismus clinic from a health center visual screening because of his visual acuities, which did not correspond to the normal acuities of his age; strabismus was also suspected. His parents had been told earlier that the father's ( A, III- I) disease could not be inherited by the son ( Leber's heredi­tary optic neuropathy was probably suspected). However, all the classical symptoms of OOA could be detected. The color vision examination also con­firmed the presence of OOA. The boy only saw correctly one of the five plates in the Lanthony Tritan Album, indicating a strong tritan defect. Of the 16 Velhagen Pflugertrident plates, he correctly saw 6, indicating a red- green defect. Case 2 In tests 1- 5, illumination was provided by the Mac­beth Easel lamp, 1000 lux. The performance of the patients in the color vi­sion tests is seen in Table 1. Examples of the results in the FM 100 test with a tritan axis ( Family B, II- 3) and a deutan axis ( Family 0, II- 2) are seen in Figs. 2 and 3. In Table 2, the findings in the color vision of the patients are summarized. Three case reports are presented to show differ­ent kinds of color vision defects and the use of various color vision tests in OOA. FAMILY B FAMILY D • EXAMINED ~ U2l ~ ~~ c?; • I · 2 AFFECTED • o DECEASED ? QUESTIONABLY AFFECTED FIG. 1. The family pedigrees. MALE FEMALE FAMILY A FAMILY C 8 2 II • 1 III • 1 · 2 Do IV IU II J Clin Neuro- ophthalmol, Vol. 12, No. 2, 1992 lUO M. I. MANTy/ ARVI ET AL. TABLE 1. Characteristics of the patients and the results of the color vision tests Family A Family 8 Family C Family 0 11- 4 111- 1 IV- l 11- 3 11- 1 11- 2 111- 1 Age, yr 62 23 4 40 38 37 9 Sex F M M M M F F VA. aD as 20/ 200 20/ 200 20/ 100 20/ 100 20/ 200 20/ 200 20/ 40 20/ 40 20/ 30 20/ 25 20/ 50 20/ 40 20/ 50 20/ 30 SPP2 numbers correct AG. aD as 0/ 5 0/ 5 2/ 5 2/ 5 2/ 5 3/ 5 5/ 5 5/ 5 1/ 5 1/ 5 1/ 5 1/ 5 8. ADOS 0,10 0/ 10 4/ 10 4/ 10 0/ 10 0/ 10 7/ 10 4/ 10 10/ 10 10/ 10 10/ 10 10/ 10 FM 100 error score aDOS 1234 1065 673 625 321 337 304 308 325 266 Axis tritan tritan ( Fig. 2) tritan deutan ( Fig. 3) Aayleigh equation ( AG) AQ. aD as DA DA 08 08 08 08 1.1 1.2 1.0 1.1 2.0 1.4 MR, aD as 73 73 15 15 17 17 7 7 25 25 14 7 Moreland equation ( 8) AQ. aD as 04 TA 06 06 12 15 1.2 1.4 1.0 1.2 MR. aD as 54 90 60 60 20 23 21 27 10 10 Vel hagen plates correct 6/ 16 Tritan Album plates correct 1/ 5 Panel D 15 deutan deutan F, female: M. male: 00. rlght eye: OS. left eye: VA. visual acuity: RG, red- green: 8. blue: AQ. anomalous quotient; MA, matching range: OA, deuteranopia: TA, tritanopia. Case 3 This 37- year- old woman ( Family 0, II- 2) had had decreased visual acuity since her early school years. She had no particular difficulties until the present time when she began to study again. She went to an ophthalmologist for glasses, was sent for further examination to our clinic, and DOA was diagnosed. Her visual acuity was 20/ 50 in the right and 20/ 40 in the left eye. In the FM 100 test, she ... -'. ... ::::::::::~--:--:-~, I J' ..' FIG. 2. The FM 100 test result with a tritan axis of the patient in the Family B. 11 · 3 ( right eye). COLOR VISION IN DOMINANT OPTIC ATROPHY 101 ~.', ," ". '" ,,, , i , I j i ..' FIG. 3. The FM 100 test result with a deutan axis of the patient in the Family D, 11- 2 ( right eye). had a large error score of 325 in the right and 266 in the left eye, with a deutan axis ( Fig. 3). In the Nagel anomaloscope, she showed a large MR in both eyes with an AQ within the normal range, indicating an undefined red- green defect. In the Besancon anomalometer, her result was normal. In the SPP2 plates, she correctly sawall of the ten blue numbers but only one of the five red- green numbers. In the Panel 0 15 test, she had a distinct deutan pattern. TABLE 2. Findings in the color vision of seven DOA patients Family and Color vision patients Red- green Blue A 11- 4 Strong deutan Strong tritan 111- 1 Mild undefined defect Strong tritan IV- l Undefined defect Strong tritan B 11- 3 Mild undefined defect Medium tritan C 11- 1 Normal Medium tritan 0 11- 2 Medium deutan Normal 111- 1 Mild deutan Normal DISCUSSION The color vision defect in dominant optic atro­phy varies considerably, as the small number of patients in the present study shows. However, within one family the defect seems to be of the same type. This was also observed in an earlier study by Kok- van Alphen ( 2). In the four families with DOA members that were studied, only red­green defects were discovered in two, one family had blue defects, and one family had mixed red­green and blue defects. The color vision test used was the Hardy- Rand- Rittler ( HRR) plate test, which can distinguish red and green defects. The number of red, green, or indistinguishable defects was not mentioned. In our study, four of the seven patients had a color vision defect in both red- green and blue ar­eas. In all but one, the red- green defect was milder than the blue defect. One of our patients had only a blue defect; two patients had a green defect. In earlier studies, many patients were described with different kinds of color vision defects, most of them with mixed defects as in our study. Kjer ( 1) examined 126 patients with the Stilling blue color JClin Neuro- ophthalmol. Vol. 12. No. 2. 1992 102 M. I. MANTY/ ARV1 ET AL. plates and found 124 patients to be defective. Of these 126 patients, only 14 read the Ishihara red­green plates correctly, an indication that most of the patients had a mixed defect in the red- green and blue areas. He also stated that the blue defect was stronger than the red- green defect. Five out of seven patients in the study by Johnston et al. ( 19) had a mixed red- green and blue defect; of the re­maining two, one had only a blue defect and one had normal color vision. The color vision examina­tion was done with the Ishihara and HRR plates, the Panel D 15 test, the FM 100 test, and the Nagel anomaloscope. Thus, a very accurate profile of the color vision of these patients was obtained. Kline and Glaser ( 20) studied 14 DOA patients with the HRR plates and the FM 100 test. They found 11 patients with a mixed red- green and blue defect, defining 10 of them as deutan- tritan defects and 1 as a protan- tritan defect. Three patients had only a blue defect. Hoyt ( 21) examined 31 patients with the HRR plates and the FM 100 test. The majority of his patients, 22, had only a tritan defect. Seven patients had a mixed defect, all of them deutan­tritan, and two patients had a deutan defect. Rog­geveen et al. ( 22) made a careful color vision anal­ysis of DOA patients with the Ishihara and HRR plates, the Panel D 15 test, the Desaturated Panel D 15 test, and FM 100 test, and red- green and blue anomaloscopes. Having studied three large fami­lies with DOA patients, they reported that the color vision in DOA did not always show the typ­ical blue defect: some patients also had normal color vision, some patients had atypical defects, and a few had red- green defects. Only about half of these patients had a tritan defect in this study. A blue anomaloscope was also found to be useful in the diagnosis of DOA. A few observations exist about achromatopsia as a color vision defect in DOA ( 23- 25). However, two of these studies used only pseudoisochromatic plates, and another used the Panel D 15 with the FM 100 test. The reliable diagnosis of achromatop­sia requires additional anomaloscope ( red- green and blue) testing; the Sloan achromatopsia test could also be useful, which was well demonstrated in one of our patients. As this disease usually starts in early childhood, reliable tests for finding color vision defects in young children are needed. In the red- green area, the winding line section of the Ishihara plates is useful for testing children 3 years of age and the Velhagen Pfh. igertrident plates for testing children 4 years of age ( 26). For blue color vision, the Lan­thony Tritan Album is quite good; 3- year- old pa- JGin Neuro- ophthalrnol, Vol. 12, No, 2, UJ92 tients can interpret it reliably ( 26,27). The Vel­hagen and Lanthony plate tests . were well suited for examining the 4- year- old boy m our study. The HRR plates with figures of circle, triangle, and cross are probably also useful for examining young children. However, the HRR plates will not be available until the new edition is completed. Differential diagnosis in DOA can be difficult, especially if there are no other family members with DOA, if the first eye examination is done in adulthood, and if the history of the disease re­mains obscure. Leber's hereditary optic neuropa­thy usually starts later, in the teens or twenties, and the visual acuity is usually much worse than in DOA. The hereditary pattern is also different. If such findings as ataxia or hearing loss are ob­served, the diagnosis of DOA is more probable. Moreover, Leber's hereditary optic neuropathy can be diagnosed with the mitochondrial DNA ex­amination ( 28). Congenital recessive optic atrophy also shows worse visual acuities than DOA and is inherited differently ( 3). Congenital tritan defect might also be considered. However, the visual acuity and all other eye examinations except color vision are normal. Moreover, the electroretino­gram of blue cones is abnormal in the congenital tritan defect, but not in DOA ( 29). In our patients, the man in Family B ( II- 3) had all the clinical fea­tures of DOA, with quite a good visual acuity of 20/ 40 and the first discovery of the decreased vi­sual acuity at the age of about 7. His parents were examined and found to be healthy. Thus, he must be a sporadic case. Also, the woman in Family D ( II- 2) showed the typical symptoms of DOA. Her parents were dead; however, one of them might have had optic atrophy with reasonably good vi­sual acuity without any trouble in everyday life. But could she and her daughter have a congenital deutan defect? According to her knowledge, her dead husband might have had a congenital color vision defect. If her father had also had it, the de­fect could have been congenital. However, her and her daughter's color vision defects resembled an acquired defect, rather than a congenital defect: her Nagel anomaloscope examination did not show a clear- cut deutan response but only in­creased MRs. The anomaloscope findings of her daughter were asymmetrical, with deutan AQs unusually near normal AQs. In conclusion, in the diagnosis of dominant optic atrophy, a blue color vision defect is not the only type of defect to be expected. Different kinds of color vision defects are possible: mixed red- green and blue defects with undefined red- green and tri- COLOR VISION IN DOMINANT OPTIC ATROPHY 103 tan or deutan- tritan combinations, pure tritan de­fects, and pure deutan defects. Acknowledgment: The authors would like to thank Professor Roth of the University Eye Clinic in Geneva, Switzerland for lending us the Besancon anomalometer for this study. REFERENCES 1. Kjer P. Infantile optic atrophy with dominant mode of in­heritance. 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