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Inherited retinal disorder (IRD) is a leading cause of blindness, and CRX is one of a number of genes reported to harbour autosomal dominant (AD) and recessive (AR) causative variants. Eighteen patients from 13 families with CRX-associated retinal disorder (CRX-RD) were identified from 730 Japanese families with IRD. Ophthalmological examinations and phenotype subgroup classification were performed. The median age of onset/latest examination was 45.0/62.5 years (range, 15–77/25–94). The median visual acuity in the right/left eye was 0.52/0.40 (range, −0.08–2.00/−0.18–1.70) logarithm of the minimum angle of resolution (LogMAR) units. There was one family with macular dystrophy, nine with cone-rod dystrophy (CORD), and three with retinitis pigmentosa. In silico analysis of CRX variants was conducted for genotype subgroup classification based on inheritance and the presence of truncating variants. Eight pathogenic CRX variants were identified, including three novel heterozygous variants (p.R43H, p.P145Lfs*42, and p.P197Afs*22). A trend of a genotype-phenotype association was revealed between the phenotype and genotype subgroups. A considerably high proportion of CRX-RD in ADCORD was determined in the Japanese cohort (39.1%), often showing the mild phenotype (CORD) with late-onset disease (sixth decade). Frequently found heterozygous missense variants located within the homeodomain underlie this mild phenotype. This large cohort study delineates the disease spectrum of CRX-RD in the Japanese population.

The retinitis pigmentosa 2 (RP2) gene is one of the causative genes for X-linked inherited retinal disorder. We characterized the clinical/genetic features of four patients with RP2-associated retinal disorder (RP2-RD) from four Japanese families in a nationwide cohort. A systematic review of RP2-RD in the Japanese population was also performed. All four patients were clinically diagnosed with retinitis pigmentosa (RP). The mean age at examination was 36.5 (10-47) years, and the mean visual acuity in the right/left eye was 1.40 (0.52-2.0)/1.10 (0.52-1.7) in the logarithm of the minimum angle of resolution unit, respectively. Three patients showed extensive retinal atrophy with macular involvement, and one had central retinal atrophy. Four RP2 variants were identified, including two novel missense (p.Ser6Phe, p.Leu189Pro) and two previously reported truncating variants (p.Arg120Ter, p.Glu269CysfsTer3). The phenotypes of two patients with truncating variants were more severe than the phenotypes of two patients with missense variants. A systematic review revealed additional 11 variants, including three missense and eight deleterious (null) variants, and a statistically significant association between phenotype severity and genotype severity was revealed. The clinical and genetic spectrum of RP2-RD was illustrated in the Japanese population, identifying the characteristic features of a severe form of RP with early macular involvement.

Purpose Cone/cone-rod dystrophy is a large group of retinal disorders with both phonotypic and genetic heterogeneity. The purpose of this study was to characterize the phenotype of eight patients from seven families harboring POC1B mutations in a cohort of the Japan Eye Genetics Consortium (JEGC). Methods Whole-exome sequencing with targeted analyses identified homozygous or compound heterozygous mutations of the POC1B gene in 7 of 548 families in the JEGC database. Ophthalmologic examinations including the best-corrected visual acuity, perimetry, fundus photography, fundus autofluorescence imaging, optical coherence tomography, and full-field and multifocal electroretinography (ERGs) were performed. Results There were four men and four women whose median age at the onset of symptoms was 15.6 years (range, 6-23 years) and that at the time of examination was 40.3 years (range, 22-67 years). The best-corrected visual acuity ranged from -0.08 to 1.52 logMAR units. The funduscopic appearance was normal in all the cases except in one case with faint mottling in the fovea. Optical coherence tomography revealed an absence of the interdigitation zone and blurred ellipsoid zone in the posterior pole, but the foveal structures were preserved in three cases. The full-field photopic ERGs were reduced or extinguished with normal scotopic responses. The central responses of the multifocal ERGs were preserved in two cases. The diagnosis was either generalized cone dystrophy in five cases or cone dystrophy with foveal sparing in three cases. Conclusions Generalized or peripheral cone dystrophy with normal funduscopic appearance is the representative phenotype of POC1B-associated retinopathy in our cohort.

Biallelic variants in the EYS gene are a major cause of autosomal recessive inherited retinal disease (IRD), with a high prevalence in the Asian population. The purpose of this study was to identify pathogenic EYS variants, to determine the clinical/genetic spectrum of EYS-associated retinal disease (EYS-RD), and to discover disease-associated variants with relatively high allele frequency (1%-10%) in a nationwide Japanese cohort. Sixty-six affected subjects from 61 families with biallelic or multiple pathogenic/disease-associated EYS variants were ascertained by whole-exome sequencing. Three phenotype groups were identified in EYS-RD: retinitis pigmentosa (RP; 85.94%), cone-rod dystrophy (CORD; 10.94%), and Leber congenital amaurosis (LCA; 3.12%). Twenty-six pathogenic/disease-associated EYS variants were identified, including seven novel variants. The two most prevalent variants, p.(Gly843Glu) and p.(Thr2465Ser) were found in 26 and twelve families (42.6%, 19.7%), respectively, for which the allele frequency (AF) in the Japanese population was 2.2% and 3.0%, respectively. These results expand the phenotypic and genotypic spectrum of EYS-RD, accounting for a high proportion of EYS-RD both in autosomal recessive RP (23.4%) and autosomal recessive CORD (9.9%) in the Japanese population. The presence of EYS variants with relatively high AF highlights the importance of considering the pathogenicity of non-rare variants in relatively prevalent Mendelian disorders.

Purpose To determine the clinical and genetic characteristics of patients with GUCY2D-associated retinal disorder (GUCY2D-RD). Methods Fifteen patients from 12 families with inherited retinal disorder (IRD) and harboring GUCY2D variants were ascertained from 730 Japanese families with IRD. Comprehensive ophthalmological examinations, including visual acuity (VA) measurement, retinal imaging, and electrophysiological assessment were performed to classify patients into three phenotype subgroups; macular dystrophy (MD), cone-rod dystrophy (CORD), and Leber congenital amaurosis (LCA). In silico analysis was performed for the detected variants, and the molecularly confirmed inheritance pattern was determined (autosomal dominant/recessive [AD/AR]). Results The median age of onset/examination was 22.0/38.0 years (ranges, 0-55 and 1-73) with a median VA of 0.80/0.70 LogMAR units (ranges, 0.00-1.52 and 0.10-1.52) in the right/left eye, respectively. Macular atrophy was identified in seven patients (46.7%), and two had diffuse fundus disturbance (13.3%), and six had an essentially normal fundus (40.0%). There were 11 patients with generalized cone-rod dysfunction (78.6%), two with entire functional loss (14.3%), and one with confined macular dysfunction (7.1%). There were nine families with ADCORD, one with ARCORD, one with ADMD, and one with ARLCA. Ten GUCY2D variants were identified, including four novel variants (p.Val56GlyfsTer262, p.Met246Ile, p.Arg761Trp, p.Glu874Lys). Conclusions This large cohort study delineates the disease spectrum of GUCY2D-RD. Diverse clinical presentations with various severities of ADCORD and the early-onset severe phenotype of ARLCA are illustrated. A relatively lower prevalence of GUCY2D-RD for ADCORD and ARLCA in the Japanese population was revealed. Translational Relevance The obtained data help to monitor and counsel patients, especially in East Asia, as well as to design future therapeutic approaches.

To present the characteristics and pathology of a patient with congenital achromatopsia. The patient was a 22-year-old Japanese woman who was 8 years old when she first visited our clinic. Comprehensive ophthalmic examinations including visual acuity measurements, perimetry, optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, electroretinography (ERG), and color vision tests were performed. Her genomic DNA was used as the template for the amplification of exons of five candidate genes for achromatopsia; CNGA3, CNGB3, GNAT2, PDE6C, and PDE6H, and the amplified products were sequenced. A missense mutation, found in the CNGA3, was studied both electrophysiologically and biochemically. Her phenotype was typical of congenital complete achromatopsia. She was followed for 14 years, and her vision and fundus findings were stable. However, the scotopic ERG b-waves at age 22 were smaller than those at age 8, and her FAF images showed increased autofluorescence in both maculae. Genetic examinations revealed combined heterozygous mutations of c.997_998delGA and p.M424V in the CNGA3 gene. The homomeric channel consisting of the CNGA3 subunit with the p.M424V mutation had a weak cGMP-activated current in patch-clamp recordings. In heterologous expression analyses, the expression at the cell surface of the mutant CNGA3 subunit was about 28 % of the wild type. The two novel mutations found in the CNGA3 gene, c.997_998delGA and p.M424V, can cause complete achromatopsia. The vision of the patient was stationary until the third decade of life although the FAF was altered at the age of 22 years.

Purpose To determine the clinical and genetic characteristics of patients with GUCY2D-associated retinal disorder (GUCY2D-RD). Methods Fifteen patients from 12 families with inherited retinal disorder (IRD) and harboring GUCY2D variants were ascertained from 730 Japanese families with IRD. Comprehensive ophthalmological examinations, including visual acuity (VA) measurement, retinal imaging, and electrophysiological assessment were performed to classify patients into three phenotype subgroups; macular dystrophy (MD), cone-rod dystrophy (CORD), and Leber congenital amaurosis (LCA). In silico analysis was performed for the detected variants, and the molecularly confirmed inheritance pattern was determined (autosomal dominant/recessive [AD/AR]). Results The median age of onset/examination was 22.0/38.0 years (ranges, 0-55 and 1-73) with a median VA of 0.80/0.70 LogMAR units (ranges, 0.00-1.52 and 0.10-1.52) in the right/left eye, respectively. Macular atrophy was identified in seven patients (46.7%), and two had diffuse fundus disturbance (13.3%), and six had an essentially normal fundus (40.0%). There were 11 patients with generalized cone-rod dysfunction (78.6%), two with entire functional loss (14.3%), and one with confined macular dysfunction (7.1%). There were nine families with ADCORD, one with ARCORD, one with ADMD, and one with ARLCA. Ten GUCY2D variants were identified, including four novel variants (p.Val56GlyfsTer262, p.Met246Ile, p.Arg761Trp, p.Glu874Lys). Conclusions This large cohort study delineates the disease spectrum of GUCY2D-RD. Diverse clinical presentations with various severities of ADCORD and the early-onset severe phenotype of ARLCA are illustrated. A relatively lower prevalence of GUCY2D-RD for ADCORD and ARLCA in the Japanese population was revealed. Translational relevance The obtained data help to monitor and counsel patients, especially in East Asia, as well as to design future therapeutic approaches.

Purpose To investigate clinical characteristics of RDH5-related fundus albipunctatus (FAP) in a Japanese cohort. Methods Twenty-five patients from 22 pedigrees with RDH5-related FAP were studied. Ophthalmic medical records were reviewed. For genetic analysis, either Sanger sequencing of the RDH5 gene or whole-exome sequencing was performed. Results Genetic analysis identified eight different RDH5 variants, including seven known RDH5 variants (p.G35S, p.G107R, p.R167H, p.A240GfsX19, p.R278X, p.R280H, and p.L310delinsEV) and a novel variant: c.259C>T (p.Q87X). The most frequently observed variant was p.L310delinsEV (65.2%, 30/46 alleles). Of 50 eyes examined, 44 eyes (88.0%) showed logMAR best-corrected visual acuity (BCVA) of 0.10 or better. In optical coherence tomography, macular involvement was observed in 12 patients (24 eyes). Ten patients (83.3%) who had good BCVA (0.10 or better) exhibited diffuse disruption of the outer retina with foveal sparing, and two patients (16.7%) exhibited diffuse disruption throughout the macula and decreased BCVA. Among the 24 eyes, ring-or crescent-shaped hyperautofluorescence or irregular autofluorescence around the fovea was observed in 15 eyes (83.3%) of 18 eyes examined by fundus autofluorescence imaging. Full-field electroretinography showed extinguished or severely decreased rod responses in all 23 examined patients, whereas decreased cone responses were seen in 17 patients (73.9%). Conclusions Multimodal imaging and electroretinography of RDH5-related FAP revealed high frequencies of macular involvement in older patients and decreased cone responses. Our findings suggest that progressive macular/cone dysfunction, as well as delayed rod function, may be key phenotypic features of RDH5-related FAP.

DRAM2-associated retinopathy is a rare inherited retinal dystrophy, and its outcome has not been determined. A single retinal involvement by a mutation of the DRAM2 gene is unexplained. We found three unrelated patients with a disease-causing DRAM2 variant in a biallelic state from 1555 Japanese individuals of 1314 families with inherited retinal dystrophy. We reviewed their medical records and examined their peripheral lymphocytes by transmission electron microscopy (TEM). Patient 1 was a 38-year-old woman who complained of night blindness and reduced vision. She developed macular degeneration at age 43 years. Patients 2 and 3 were a man and a woman both of whom noticed night blindness in their 30s. Both had a degeneration in the macula and midperiphery in their 40s, which progressed to a diffuse retinal degeneration in their 60s when their vision was reduced to hand motions. Three novel DRAM2 variants were identified. TEM of the lymphocytes of Patients 1 and 2 showed abnormal structures in 40.6% and 0.3% of the peripheral lymphocytes, respectively. We concluded that the DRAM2-associated retinopathy of our patients was a progressive rod-cone dystrophy, and the visual outcome was poor. The systemic effect of DRAM2 mutations may be compensable and have variations.

To report the light- and dark-adapted perimetric findings in a patient with multiple evanescent white dot syndrome (MEWDS). The patient was a 25-year-old Japanese woman who underwent comprehensive ophthalmological examinations including measurements of the visual acuity, dilated ophthalmoscopy, Goldmann kinetic perimetry, electroretinography (ERG), indocyanine green fundus angiography (ICGA), and optical coherence tomography (OCT). Kinetic perimetry was performed under light- and dark-adapted conditions. The patient was diagnosed with MEWDS by the fundus and visual field findings, and the ICGA abnormalities. Light-adapted perimetry showed an enlargement of the blind spot; however, the size of the blind spot was normalized with dark-adaptation. Amplitude of cone ERG was more reduced than that of rod ERG in the affected eye. The OCT images showed multiple disruptions of the ellipsoid and interdigitation zones. These abnormalities were still present 9 months after the onset although the fundus appeared normal. These findings indicate a persistent cone-dominated dysfunction in a patient with MEWDS.

To present the clinical and genetic findings in two siblings with autosomal recessive retinitis pigmentosa (RP) and their non-symptomatic parents.We studied two siblings, a 48-year-old woman and her 44-year-old brother, and their parents. They had general ophthalmic examinations including ophthalmoscopy, perimetry, and electroretinography (ERG). Their whole exomes were analyzed by the next-generation sequence technique.The two siblings had night blindness for a long time, and clinical examinations revealed diffuse retinal degeneration with bone spicule pigmentation, constriction of the visual field, and non-recordable ERGs. Their parents were non-symptomatic and had normal fundi; however, their rod ERGs were reduced. Genetic examination revealed compound heterozygous mutations of I535N and H557Y in the PDE6B gene in the siblings, and the parents were heterozygous carriers of the mutations.Heterozygous mutation in the PDE6B gene can cause a reduction in the rod function to different degrees. The retinal function of non-symptomatic carriers of autosomal recessive RP should be evaluated with care.

To report novel mutations in the CRB1 gene in two patients with early-onset retinal dystrophy (EORD) and the longitudinal clinical course of EORD. The patients were two unrelated Japanese children. Standard ophthalmic examinations including perimetry, electroretinography, and optical coherence tomography were performed on both patients. Whole exomes of the patients and their nonsymptomatic parents were analyzed using a next-generation sequence (NGS) technique. Patient 1 was noted to have esotropia and hyperopia at age 3. His decimal best-corrected visual acuity (BCVA) was 0.6 OD and 0.3 OS at age 6 with de-pigmentation of the retinal pigment epithelium (RPE). At age 19, his central vision was still preserved; however, numerous pigment granules were present in the retina. NGS analysis revealed a p.R632X nonsense and c.652 + 1_652 + 4delGTAA splice site mutations in the CRB1 gene. Patient 2 was noted to have hyperopia at age 3. His decimal BCVA at age 6 was 0.3 OD and 0.4 OS with de-pigmented RPE. The degree of retinal pigmentation was increased but his BCVA was good until the age of 14 years. NGS analysis revealed c.652 + 1_652 + 4delGTAA and c.652 + 1_652 + 2insT splice site mutations in the CRB1 gene. The phenotypes of these novel mutations for EORD are typical of CRB1-associated EORD (LCA8). They were slowly progressive until the second decade of life.

Purpose: To report our findings in an infant with Peters anomaly type II whose retinopathy of prematurity (ROP) was treated with an anti-VEGF agent and surgeries. Case Report: A male infant weighing 548 g was born prematurely at 23 weeks and 1 day with corneal opacity and shallow anterior chambers in both eyes. At the postmenstrual age of 35 weeks and 3 days, the infant was tentatively diagnosed with stage 3 ROP because of a dilated tunica vasculosa lentis and ultrasonographic findings. The boy was treated with bilateral intravitreal injections of bevacizumab (IVB) because laser photocoagulation of the retina could not be performed due to the corneal opacity. The retina in the right eye detached 3 times, namely 5 days, 16 days, and 7 months after the IVB; encircling the scleral buckle and a vitrectomy with endolaser photocoagulation were therefore required. In his left eye, the retina was reattached after the initial IVB, and no additional treatment was required. ROP was not reactivated in both eyes until the last examination at the age of 2 years and 6 months. Conclusions: Our results showed that IVB is a useful treatment for ROP in patients with Peters anomaly. However, a retinal detachment can be a complication after IVB. The optimal timing of IVB for ROP in infants with hazy media needs to be determined.

To report the longitudinal clinical course of three Japanese patients from two families with Leber congenital amaurosis/early-onset retinal dystrophy (LCA/EORD), and the results of next-generation DNA sequences on them. The patients were three Japanese children: a 4-year-old girl, a 6-year-old boy, and a 3-year-old girl. Patients 1 and 2 were siblings, and patient 3 was from an unrelated family. Standard ophthalmic examinations including perimetry, electroretinography, optical coherence tomography, and ultrasonography were performed on each patient. The patients were observed for 28, 16, and 10 years. Whole exomes of the patients and their non-symptomatic parents were analyzed using a next-generation sequence technique. The decimal visual acuity varied between 0.07 and 0.6 at the initial visit and decreased to counting finger to hand motion in their teens. Funduscopy showed diffuse retinal and macular degeneration. During the follow-up period, a posterior staphyloma developed and the macular area became atrophic. Patient 1 developed cataracts in her early twenties. Genetic analysis revealed a homozygous A126V substitution in the RDH12 gene in all patients. The three patients with LCA/EORD had a progressive decrease of their vision with the formation of a posterior staphyloma. This is the first report of Japanese patients with LCA/EORD with a RDH12 mutation.

To evaluate the outcomes of intravitreal injection of bevacizumab (IVB) for retinopathy of prematurity (ROP). IVB was selected to be the first treatment for type 1 ROP in 8 eyes (4 patients). Bevacizumab (0.25 mg/eye) was injected into the vitreous cavity under either general anesthesia or sedation. Fundus photography and fluorescein angiography were performed before the IVB. One infant was observed to the age of 1 year 6 months, the second to 1 year 9 months, the third to 1 year 10 months, and the fourth to 2 years 0 month. Before the IVB, 6 eyes (3 patients) had ROP in zone II and 2 eyes (one patient) had ROP in zone I. The 3 infants with ROP in zone II weighed 652, 476, and 579 g with gestational ages of 24, 27, and 24 weeks at birth, respectively. The infant with ROP in zone I weighed 972 g with a gestational age of 26 weeks at birth. IVB was performed at postmenstrual ages of 33–37 weeks. The IVB was effective in all eyes with ROP in zone II and additional treatment was not required, whereas vitreous hemorrhage and cataract were found at 19 weeks and 5 months after the initial IVB in the two eyes with ROP in zone I. These two eyes required additional IVB, laser photocoagulation, and surgery. Our findings suggest that eyes with type 1 ROP in zone II can be treated with IVB. Further studies are needed with a larger number of eyes.

To assess the results of perimetry recorded under dark- and light-adapted (DA and LA) conditions in patients with acute zonal occult outer retinopathy (AZOOR) and to compare the results of electroretinography (ERG) and spectral-domain optical coherence tomography (SD-OCT) in two groups of AZOOR patients.Twelve patients with AZOOR were studied. The diagnosis of AZOOR was based on the results of ophthalmoscopy, Goldmann kinetic perimetry, and multifocal ERGs. In addition, DA and LA perimetry, ERG, and SD-OCT were performed. The patients were followed for 1-9 years.The patients were classified into two types: type A patients (3) had a scotoma detected by both DA and LA perimetry, normal or equally abnormal cone and rod ERGs, atrophy of the outer nuclear layer (ONL), and disruption of the inner segment/outer segment (IS/OS) junction line in the OCT images. Type B patients (7) had a scotoma that was more prominent in LA than in DA perimetry and a continuous IS/OS junction line in the OCT images. Two patients had characteristics of both type A and type B AZOOR.Our findings suggest that eyes with type A AZOOR have focal and severe impairment of both the rods and cones, and eyes with type B AZOOR have focal and specific impairment of the cones.

BACKGROUND We report our findings in two siblings with late-onset cone-rod dystrophy (CRD) with no visible macular degeneration. CASES AND METHODS Case 1 was an 82-year-old man who first noticed a decrease in vision and color blindness in his early seventies. His mother and younger sister also had visual disturbances. His decimal visual acuity was 0.3 in the right eye and 0.2 in the left eye. Ophthalmoscopy showed normal fundi, and fluorescein angiography was also normal in both eyes. The photopic single flash and flicker eletroretinograms (ERGs) were severely attenuated and the scotopic ERGs were slightly reduced in both eyes. Case 2 was the 80-year-old younger sister of Case 1. She first noticed a decline in vision and photophobia in both eyes in her early seventies. Her decimal visual acuity was 0.4 in the right eye and 0.2 in the left eye. Ophthalmoscopy showed mottling of the retinal pigment epithelium in the midperiphery with no visible macular degeneration. The photopic single flash and flicker ERGs were severely attenuated, and the scotopic ERGs were slightly reduced in both eyes. CONCLUSION These siblings are the oldest reported cases of CRD with no visible macular degeneration. Thus, CRD should be considered in patients with reduced visual acuity, color blindness, and photophobia even if they are older than 70 years.

Purpose To determine the clinical and genetic characteristics of Japanese patients with occult macular dystrophy (OMD) in a nationwide multicenter study. Methods Twenty-three patients from 21 families with clinically diagnosed OMD were studied at 10 institutions throughout Japan. Ophthalmologic examinations including spectral-domain optic coherence tomography were performed. Patients were classified into two phenotype groups: a classical group having both blurred ellipsoid zone and absence of interdigitation zone of the photoreceptors, and a nonclassical group lacking at least one of these two features. Whole-exome sequencing, direct sequencing, and in silico molecular analysis were performed to detect the pathogenic RP1L1 variants. Statistical associations between the phenotype and genotypes based on the presence of pathogenic RP1L1 variants were investigated. Results There were 12 families with the classical findings and 9 families with the nonclassical findings. Nine pathogenic RP1L1 missense variants were identified in 12 families (57%) including three reported variants, namely, p.R45W, p.S1199C, and p.G1200A, and six novel variants, p.G221R, p.T1194M, p.T1196I, p.G1200D, p.G1200V, and p.V1201G. The pathogenic missense variants in seven families (33%) were located between amino acid numbers 1196 and 1201. A significant association was found between the photoreceptor microstructural phenotypes and molecular genotypes. Conclusions The spectrum of the morphologic phenotypes and pathogenic RP1L1 variants was documented in a well-characterized Japanese cohort with OMD. A unique motif including six amino acids (1196-1201) downstream of the doublecortin domain could be a hot spot for RP1L1 pathogenic variants. The significant association of the morphologic phenotypes and genotypes indicates that there are two types of pathophysiology underlying the occult macular dysfunction syndrome: a hereditary OMD with the classical phenotype (Miyake's disease), and a nonhereditary OMD-like syndrome with progressive occult maculopathy.

To report a case of bilateral, acquired, and acute dysfunction of short-wavelength-sensitive (SWS) cone systems. The case was a healthy 39-year-old man. He noticed sudden onset of bilateral abnormal color vision. Ophthalmic examinations revealed normal fundi in both eyes. Farnsworth panel D-15 test and Farnsworth-Munsell 100-hue test showed tritanopia. White-on-white static perimetry showed no abnormality; however, blue-on-yellow static perimetry detected remarkably reduced sensitivity at the lower visual field in both eyes. ISCEV-standard full-field electroretinograms (ERGs) were normal; however, blue-on-yellow ERGs showed reduced amplitude of b-wave that was derived from SWS cone systems in both eyes. He was observed for 1 year, and no improvement in color vision was found during the observation. This is a unique case which showed bilateral, acquired, and acute dysfunction of SWS cone systems. The cause of the acquired tritanopia remains to be known.