Sanae Muraki

Surgical Results of a Muscle Transposition Procedure for Abducens Palsy Without Tenotomy and Muscle Splitting

PURPOSE To report a simple muscle transposition procedure without tenotomy or muscle splitting to treat abducens palsy. DESIGN Retrospective, interventional, consecutive case series. METHODS Nine patients with esotropia resulting from abducens palsy whose eyes could not abduct beyond the midline underwent this muscle transposition procedure, in which a suture was inserted through the temporal margin of each vertical rectus muscle. The same monofilament suture also was inserted into each inferotemporal or superotemporal sclera. The lateral margin of each vertical rectus muscle was transposed superotemporally or inferotemporally and was sutured onto the sclera. All 9 patients underwent unilateral muscle transposition, and 6 of the 9 underwent a medial rectus muscle recession combined with muscle transposition in the same eye. RESULTS The surgical correction by muscle transposition alone ranged from 24 to 36 prism diopters, and that by muscle transposition and recession of the medial rectus muscle ranged from 50 to 62 prism diopters. The mean correction was 46.3 ± 13.1 prism diopters per eye. All paretic eyes could abduct beyond the midline. No major vertical ductional disturbances developed. Anterior segment ischemia did not occur in any patients. CONCLUSIONS This procedure, which achieved the same corrective results as other popular procedures, is simple to perform because it requires only a suture from the muscle to sclera. Tenotomy or splitting of the transposed muscles is unnecessary.

Optical Coherence Tomography Angiography in a Patient with Optic Atrophy After Non-arteritic Anterior Ischaemic Optic Neuropathy

ABSTRACT A 75-year-old female noticed a lower visual field (VF) defect in the right eye. A diagnosis of non-arteritic anterior ischaemic optic neuropathy (NAION) was made. The lower VF defect in the right eye did not change after onset. Optical coherence tomography (OCT) angiograms on the disc and the macula showed decreased retinal perfusion in the upper retina of the right eye. Retinal nerve fibre layer loss and ganglion cell complex loss in the upper retina were also seen in the right eye. OCT angiography could non-invasively detect the decrease of the retinal perfusion due to NAION.

Evaluation of Acquired Color Vision Deficiency in Glaucoma Using the Rabin Cone Contrast Test

PURPOSE To evaluate acquired color vision deficiency in glaucoma by using the Rabin cone contrast test (RCCT). METHODS Twenty-seven eyes of 27 patients with glaucoma (glaucoma group) and 27 eyes of 27 normal subjects (control group) were included in this study. Long (L), medium (M), and short (S) CCT scores (L CCTs, M CCTs, and S CCTs, respectively) were measured using the RCCT in both groups. Visual field examinations were performed with Humphrey automated perimetry using the Swedish interactive thresholding algorithm 30-2, and the mean deviation (MD) was evaluated. The macular ganglion cell/inner plexiform layer (GCIPL) thickness was measured using high-definition optical coherence tomography in the glaucoma group. RESULTS The mean M CCTs and S CCTs in the glaucoma group were significantly lower (P<0.05 for both comparisons) than in the control group (M CCTs, 80.7±16.8 vs. 91.9±8.22; S CCTs, 83.9±19.5 vs. 97.4±3.77, respectively); the L CCTs did not differ significantly (P=0.065) from those of the controls (91.8±12.8 vs. 97.4±3.50, respectively). The M CCTs and S CCTs were correlated significantly with those of MD (M CCTs, r=0.47; S CCTs, r=0.44; P<0.05 for both comparisons) and GCIPL thickness (M CCTs, r=0.70; P<0.0001; S CCTs, r=0.57; P<0.01). CONCLUSIONS The chromatic discrimination thresholds measured by RCCT in the glaucoma group were significantly different from those measured in the control group and were correlated with the MD and GCIPL thickness. The RCCT may be useful for evaluating acquired color vision deficiency in glaucoma and may help advance current understanding of the pathophysiology of glaucomatous damage.

Optical Coherence Tomography Angiography of Retinal Perfusion in Chiasmal Compression

BACKGROUND AND OBJECTIVE To evaluate the retinal perfusion in patients with chiasmal compression using optical coherence tomography angiography (OCTA). PATIENTS AND METHODS Retinal perfusion was evaluated using OCT angiograms in eight eyes of four patients with visual field (VF) defects due to chiasmal compression treated by tumor resection. The retinal perfusion in the area corresponding to the quadrants of the VF defects was investigated in each image. The vessel density was defined as the percentage area occupied by the vessels in the image. RESULTS The decreased peripapillary retinal perfusion correlated with the quadrants of the VF defects on OCT angiograms in all patients. The binarized vessel density decreased, corresponding to the degree of VF defects in all patients. CONCLUSIONS A decrease in peripapillary retinal perfusion correlates with the quadrants of the VF defects due to chiasmal compression. This decrease can be noninvasively measured by OCTA. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:724-729.].

Evaluation of clinical validity of the Rabin cone contrast test in normal phakic or pseudophakic eyes and severely dichromatic eyes

To evaluate the clinical validity of the Rabin cone contrast test (RCCT; Innova Systems, Inc.) in patients with normal phakic/pseudophakic eyes and severe dichromatic colour vision deficiency (CVD).

Usefulness of Intravitreal Bevacizumab for Retinopathy of Prematurity with Severely Dilated Tunica Vasculosa Lentis and Poor Mydriasis

Background: Laser therapy has been the gold standard treatment for retinopathy of prematurity (ROP), while intravitreal bevacizumab (IVB) is reported to be of significant benefit for zone I ROP. A problem with laser therapy is that it is difficult to administer in ROP patients with severely dilated tunica vasculosa lentis and poor mydriasis. However, although IVB treatment has been performed in such severe ROP cases, only 1 report has discussed its usefulness. Case 1: A male infant was born with a birth weight of 382 g at 23 weeks’ gestation. As visualization was poor and laser therapy could not be performed due to dilated tunica vasculosa lentis and poor mydriasis, IVB (0.625 mg/0.025 mL) was administered to both eyes. Following treatment, the ROP gradually improved, with regression of the dilated tunica vasculosa lentis and improvement of the mydriasis in both eyes. Case 2: A male infant was born with a birth weight of 698 g at 25 weeks’ gestation. As laser therapy could not be performed due to severely dilated tunica vasculosa lentis and poor mydriasis, IVB (0.625 mg/0.025 mL) was administered to both eyes. Following treatment, the ROP gradually improved, with regression of the dilated tunica vasculosa lentis and improvement of the mydriasis in both eyes. Conclusions: IVB is potentially more useful than laser therapy for the treatment of severe ROP with dilated tunica vasculosa lentis and poor mydriasis.

Novel mutations in the L visual pigment gene found in Japanese men with protan color-vision defect having a normal order L/M gene array

Among congenital color-vision defects, protan-(L [long wavelength-sensitive]cones are affected) and deutan-(M [medium wavelength-sensitive]cones are affected) defects are common. Both defects have phenotypes with dichromacy (protanopia and deuteranopia, respectively) and anomalous trichromacy (protanomaly and deuteranomaly, respectively). The genes for L pigment (expressed in L-cones) and M pigment (expressed in M-cones) are arranged in tandem to form an L/M gene array on the human X chromosome, with the L gene first and M gene (s) downstream in color-normal men. In this study, we call such an array an “L-M array.” Since the L and M genes are similar to each other in structure as well as at nucleotide level, non-homologous recombination tends to occur between these genes, leading to an abnormal single-M or M-M array, causing a protan defect, or single-L or L-L array, causing a deutan defect. With regard to arrays consisting of more than two genes, it is widely accepted that when products from the first two genes of an array are spectrally identical, the phenotype is dichromacy (protanopia or deuteranopia) and when they are spectrally different to each other, the phenotype is anomalous trichromacy (protanomaly or deuteranomaly). We have been analyzing L/M gene arrays in Japanese men with protan or deutan defect to study correlations of the array genotype with a subject’s color-vision phenotype. Analysis of gene arrays in a total of 236 Japanese men with protan defect until now revealed that more than a few men had an L gene at the first position (8 in the 135 men with protanopia and 6 in the 101 men with protanomaly [Table 1]), which does not agree with the non-homologous recombination mechanism as a cause of the color-vision defect. Such a high frequency (14 in a total of 236, 5.9%) has never been reported in Caucasians with protan defect, being 0 in 23 protans, 0 in 23 and 1 in 37. The only one Caucasian man with protan defect in reference 8 had a rare LIAVA haplotype, which consists of Leu-Ile-AlaVal-Ala, in exon 3 of the L gene. We have also found this haplotype in two Japanese men, as shown in Table 1. Since we have already reported abnormalities of the L genes in 11 of the 14 men, we analyzed the L genes of the other three men in the present study, and mutations such as Trp177STOP, −99T>G, and +3A>C in intron 2 were newly identified (Table 1). The nonsense mutation is the second identified one in our study (Table 1). The −99T>G substitution was at the PCE-1 (photoreceptor conserved element-1) site. Although a −71A>C substitution was reported in the M gene, abnormalities in the L gene promoter have never been documented. Since the PCE-1 sequence was frequently found in the promoter of photoreceptor-specific genes such as arrestin, interphotoreceptor retinoid-binding protein, rhodopsin, and cone opsin genes, the sequence would be necessary for the development of photoreceptor cells. Its consensus sequence is CAATTAR. The corresponding sequence in the wild-type L gene promoter is CAATTAA (perfect match). The −99T>G substitution causes one mismatch which may avoid binding of a specific protein for transcription to the element, resulting in a decrease of transcription activity. However, we found instead a slight increase in activity in the mutant promoter when compared to the wild-type promoter in the luciferase reporter assay (Supplemental Figure 1A – online only). In the gel retardation assay, the shifted band disappeared for the wild-type competitor but not for the mutant (−99T>G) competitor at 100-fold excess (Supplemental Figure 1B – online only). The mutant sequence did not seem to bind to the PCE-1specific binding protein. The mutation at intron 2 (+3A>C) was within the consensus sequence for the 5′ splice site, MAG|GTRAGT (the vertical bar represents the boundary of exon and intron). We analyzed this mutation by using minigenes consisting of L opsin cDNA and the genomic region of intron 2 exon 3 intron 3. Figure 1A shows that the mutant minigene yielded a slightly smaller product than the wild-type minigene. By sequencing the product of the mutant minigene, we found that the splicing had occurred just behind codon 114 in exon 2 (Figure 1B). The aberrant splicing eliminated 67 nucleotides from the mature mRNA and is supposed to cause premature termination of translation at codons 162-163 in exon 3. The RT-PCR product from the mutant minigene was less in amount than that from the wild-type minigene (Figure 1A). This was probably due to the nonsense-mediated mRNA decay mechanism which was activated by the resultant stop codon in exon 3. The

Long-Term Outcomes of Three Cases That Underwent a Muscle Transposition Procedure Without Tenotomy Caused by Abducens Palsy.

Abstract Few reports have discussed long-term outcomes of muscle transposition procedures. In this study, cases with abducens palsy treated with a muscle transposition procedure were followed for 12, 25, or 26 years. The preoperative alignments were esotropia of 65 degrees, 47 prism dioptres (PD), and 24 PD, respectively. Orthophoria was postoperatively achieved in all cases. The postoperative alignment in one case deteriorated at 8 years postoperatively, although orthophoria were maintained in the other two cases. These findings indicate that it is possible that esotropia can recur even though orthophoria was maintained for several years postoperatively in some cases that underwent a muscle transposition procedure.

Successful Repair of a Traumatic Medial Rectus Laceration with the Aid of Computed Tomography

ABSTRACT A 79-year-old woman suffered ocular trauma from an umbrella. Exotropia of the left eye was observed, and the left eye could not adduct to the midline. Both edges of the lacerated medial rectus were sutured together with the aid of preoperative computed tomography (CT), which showed posterior muscle belly widening due to posterior slippage toward the equator. The alignment and ocular movement were improved postoperatively. Repairing a lacerated medial rectus is difficult because its edge slips into the muscle cone posteriorly. Preoperative CT was useful in identifying the posterior portion of the lacerated muscle, enabling successful repair.

A new subset of deutan colour vision defect associated with an L/M visual pigment gene array of normal order and −71C substitution in the Japanese population

In 524 Japanese individuals with deutan colour vision defect, 76 had a normal-order pigment gene array, where the L gene is at the first position and the M gene(s) is located downstream. Of these 76 individuals, 69 had a -71A>C substitution in the M gene without any other mutation. Because the expression of L/M genes is up-regulated by thyroid hormone (T3) in human retinoblastoma WERI cells, we examined the effects of T3 on promoter activity; T3 increased the activity of the -71A promoter 2-fold, but it had no effect on the -71C promoter. Similarly, the -71C promoter was much less activated by T3 than the -71A promoter in HEK293 cells expressing thyroid hormone receptor isoform β2. Such a weak response of the -71C promoter to T3 may cause a decrease in the number of M cones and/or the density of M pigment during the differentiation of M cones. The average Rayleigh match midpoint was 18.9 ± 4.1 in 162 ordinary deuteranomaly individuals, but was 37.3 ± 9.1 in 63 deuteranomaly individuals with -71C. The -71A>C substitution was found to be specific to eastern Asia. These results suggest that there may be a new subset of deuteranomaly associated with -71C in the Japanese (and probably eastern Asian) population(s).