Evaluation of Pigment Distribution and Depth Analysis Methods for Decorative Soft Contact Lenses.

OBJECTIVES: This study evaluates pigment component distribution and depth in decorative soft contact lenses (DSCLs) using a variety of analytical methods. METHODS: We sampled 18 DSCLs using optical microscopy, optical coherence tomography analysis, Z-stack analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX), and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to evaluate the distribution and depth of pigment components. RESULTS: Pigment distribution in DSCLs was easily observed with optical methods including Z-stack analysis. X-ray photoelectron spectroscopy, SEM/EDX, and TOF-SIMS were used to evaluate the level of pigment exposure on the lens surface and the results showed significant differences between the methods. Pigment components were detected in 16 samples by SEM/EDX, but not by XPS. Pigment components were only detected in eight samples using TOF-SIMS. CONCLUSIONS: It may be necessary to show that a nanometer-thick monomolecular film does not exist on the surface of DSCLs, to demonstrate the exposure of a pigment particle. Taking into account the principle behind each of the measurement methods and the resolution and sensitivity of each of the analytical methods compared, TOF-SIMS may be the most appropriate method to accurately judge pigment exposure on DSCLs. The Z-stack method may be useful for estimating the depth of pigment components in DSCLs.

The effects of vitamin A compounds on hyaluronic acid released from cultured rabbit corneal epithelial cells and keratocytes.

A role of vitamin A in the synthesis of hyaluronic acid by skin cells is well known. Hyaluronic acid is produced by corneal epithelial cells and keratocytes in the eye. We investigated whether rabbit corneal epithelial cells and keratocytes release hyaluronic acid after exposure to vitamin A compounds. Rabbit corneal epithelial cells and keratocytes were inoculated with RCGM2 medium and incubated at 37ºC under 5% CO(2) in air for 24 h. The medium was then replaced with medium containing 0.1, 1, 10, or 100 µM retinoic acid or retinol palmitate (VApal) and incubated for another 48 h. Hyaluronic acid release from both corneal epithelial cells and keratocytes during culture was increased by retinoic acid at the lower concentration of 0.1 µM and 1 µM determined with a sandwich binding protein assay kit. However, it was significantly decreased at the higher concentrations of 10 µM and 100 µM, and the cell count determined with a Neutral Red assay kit was also decreased at these concentrations. On the other hand, hyaluronic acid release from corneal epithelial cells during culture was increased by VApal at the lower concentration of 0.1 µM and 1 µM, but there was no significant difference in the cell count for either corneal epithelial cells or keratocytes in the presence of VApal at any concentration. In conclusion, it is suggested that vitamin A stimulates the release of hyaluronic acid from cultured rabbit corneal epithelial cells and keratocytes.

Mutation analysis of CHST6 gene in Chinese patients with macular corneal dystrophy.

PURPOSE: To examine the carbohydrate sulfotransferase 6 (CHST6) gene in Chinese patients with macular corneal dystrophy (MCD). METHODS: Nineteen unrelated Chinese families with MCD, including 24 patients and 3 unaffected relatives, were examined. Genomic DNA was extracted from peripheral blood leukocytes. The coding region of the CHST6 gene was amplified by the polymerase chain reaction, and the DNA fragments were directly sequenced. Fifty unrelated normal Chinese volunteers served as the controls. RESULTS: Eighteen different mutations in the CHST6 gene (including 15 novel mutations) were identified, of which 12 were missense mutations, 5 were nonsense mutations, and 1 was a frameshift mutation. Six families had homozygous mutation, and 13 families had compound heterozygous mutation. None of these mutations were detected in the normal controls. CONCLUSIONS: CHST6 mutations may be responsible for the pathogenesis of MCD in Chinese patients. The Q298X mutation detected in 5 of 19 families (6 of 38 alleles, 15.8%) may be the founder mutation in Chinese patients. However, our findings also indicate a high level of allelic heterogeneity of the CHST6 gene in Chinese patients and in other ethnic groups.

A novel mutation in the cornea-specific keratin 12 gene in Meesmann corneal dystrophy.

PURPOSE: To report a novel mutation in the keratin 12 gene (KRT12) found in a Japanese family in association with Meesmann corneal dystrophy (MECD). METHODS: After informed consent was obtained, genomic DNA was extracted from the leukocytes of the peripheral blood of the proband, her affected father, normal mother, and 50 normal unrelated volunteers. Exons 1-8 of the KRT12 gene were amplified by polymerase chain reaction and directly sequenced. RESULTS: A novel heterozygous T to G transversion at the second nucleotide position of codon 433 (CTG>CGG), resulting in the replacement of leucine by arginine at codon 433 of the KRT12 gene (L433R), was detected in the proband and her affected father but not in her normal mother or the 50 controls. CONCLUSIONS: The novel L433R mutation of the KRT12 gene found in two members of this Japanese family caused MECD.

Bifocal contact lenses: History, types, characteristics, and actual state and problems.

Since people who wear contact lenses (CL) often continue using CL even when they develop presbyopia, there are growing expectations for bifocal CL. To understand actual state and problems, history, types, and their characteristics are summarized in this review. Bifocal CL have a long history over 70 years. Recently, bifocal CL have achieved remarkable progress. However, there still is an impression that prescription of bifocal CL is not easy. It should also be remembered that bifocal CL have limits, including limited addition for near vision, as well as the effects of aging and eye diseases in the aged, such as dry eye, astigmatism, cataract, etc. Analysis of the long-term users of bifocal CL among our patients has revealed the disappearance of bifocal CL that achieved unsatisfactory vision and poor contrast compared with those provided by other types of CL. Changing the prescription up to 3 times for lenses of the same brand may be appropriate. Lenses that provide poor contrast sensitivity, suffer from glare, or give unsatisfactory vision have been weeded out. The repeated replacement of products due to the emergence of improved or new products will be guessed.

A novel variant lattice corneal dystrophy caused by association of mutation (V625D) in TGFBI gene.

PURPOSE: To characterize the molecular defect in the TGFBI gene in a Chinese family affected with an atypical lattice corneal dystrophy. DESIGN: Case report and experimental study. METHODS: Molecular genetic analysis was performed on the DNA extracted from peripheral leucocytes from a Chinese family with atypical lattice corneal dystrophy. Fifty normal unrelated subjects of Chinese origin were used as controls. All exons of the TGFBI gene were amplified by polymerase chain reaction and directly sequenced. RESULTS: Bilateral, symmetrical, ridgy round pattern of opacities with uneven surfaces and thin lattice lines were noted in the proband. Analysis of exon 14 revealed a heterozygous T to A transition on codon 625. The mutation was not detected in the unaffected family member and 50 unaffected individuals. CONCLUSIONS: The novel TGFBI gene mutation (V625D) is associated with an early-onset variant of lattice corneal dystrophy. This case highlights the utility of molecular genetic analysis in differentiating corneal dystrophies associated with an atypical phenotype from nondystrophic conditions.

Novel mutation (V505D) of the TGFBI gene found in a Chinese family with lattice corneal dystrophy, type I.

PURPOSE: To report a novel V505D mutation of the human transforming growth factor beta-induced (TGFBI) gene found in a Chinese family with lattice corneal dystrophy, type I (LCDI). METHODS: Genomic DNA was extracted from peripheral leukocytes from eight affected and four unaffected members of a Chinese family with LCDI. Exons of the TGFBI gene were amplified by polymerase chain reaction and directly sequenced. Fifty normal Chinese individuals were also analysed as controls. Histopathological examination of a corneal button was performed after keratoplasty of the proband. RESULTS: A heterozygous single-base-pair transversion (GTC to GAC, valine to aspartic acid) at codon 505 in exon 11 of the TGFBI gene (V505D) was detected in all of the affected members. No mutation was found in the unaffected members or in the 50 normal controls. The mutation cosegregated with the disease phenotype throughout three generations. Although a slit-lamp examination showed features of LCDI in most cases, the age at onset of the symptoms was several years later than that in cases of LCDI with an R124C mutation. By histopathological examination, numerous amyloid deposits were observed in the stroma, including beneath Bowman's membrane. CONCLUSION: A novel V505D mutation in the TGFBI gene causes LCDI in this Chinese family. It is the fourth reported mutation of the TGFBI gene associated with LCDI.

[Analysis of gene mutation in Chinese patients with Reis-Bücklers corneal dystrophy].

OBJECTIVE: To identify the mutation of the TGFBI gene in Chinese patients with Reis-Bücklers corneal dystrophy, and to study the relationship between the gene mutation and the clinical appearance. METHODS: Ten patients and 2 unaffected family members from 2 unrelated families with corneal dystrophy were studied. Molecular genetic analysis was performed on DNA extracted from peripheral leucocytes, and exons 4 and 12 of the TGFBI gene were amplified by polymerase chain reaction for direct sequencing. RESULTS: Both pedigrees showed an autosomal dominant inheritance. The clinical appearance of the cornea consisted of fine granular, subepithelial opacities which spread and become confluent with time, and resembled geographic type of Reis-Bücklers corneal dystrophy. Direct sequencing of all affected members revealed a G-to-T transition at codon 124 (CGC to CTC), producing R124L mutation of TGFBI gene. CONCLUSIONS: R124L mutation of the TGFBI gene is found in two Chinese families with Reis-Bücklers corneal dystrophy. The phenotype of Reis-Bücklers corneal dystrophy in both families belongs to the geographic type. Molecular genetic approach may be useful for the proper diagnosis of this type of corneal dystrophy.

[Case of late onset and isolated lattice corneal dystrophy with Asn544Ser (N544S) mutation of transforming growth factor beta-induced (TGFBI, BIGH3) gene].

PURPOSE: To report a case of lattice corneal dystrophy (LCD) with Asn544Ser (N544S) mutation of the transforming growth factor beta-induced (TGFBI) gene. CASE: A 68-year-old male patient with late-onset, sporadic LCD without corneal erosion. Amyloid deposits showing dot and lattice lines were seen in the mid to deep stroma. After obtaining appropriate informed consent, genomic DNA was amplified by polymerase chain reaction (PCR) and directly sequenced. RESULTS: A heterozygous single base pair transition (AAT --> AGT), resulting in substitution of serine for asparagine at codon 544 of the TGFBI gene, was detected. CONCLUSION: The case was classified as atypical type IV because of the late onset, lack of corneal erosion, and amyloid deposits in the mid to deep stroma.

Microarray analysis identified differentially expressed genes in keratocytes from keratoconus patients.

PURPOSE: To identify differentially expressed genes in human keratoconus keratocyte by cDNA microarray. METHODS: Normal and keratoconic cornea were cultured for keratocytes. RNA was extracted. cDNA probe labeled with fluorescence dye was made from Poly A+ RNA, hybridized with microarray slide, containing 164 human apoptosis genes. Signal intensity was measured. Expression ratio between keratoconus and normal was determined using ImaGene Ver.3.0. Identified genes were further evaluated by RT-PCR and real-time PCR. RESULTS: Five over-expressed and four under-expressed genes were identified. Of these, differential expression of tumor necrosis factor alpha-induced protein 6 (TNFAIP6), human insulin-like growth factor binding protein 5 (IGFBP5), and IGFBP3 were verified and confirmed by RT-PCR. Real-time PCR showed TNFAIP6 increased by 3.3 folds, while IGFBP5, IGFBP3 decreased by 14 and 11 folds respectively. CONCLUSIONS: The identified genes could be important and deserve further investigation. Significant differential expression of TNFAIP6, IGFBP5, and IGFBP3 may indicate an important role of these genes in the mechanism underlying stromal thinning.

Truncation and mutagenesis analysis of the human X-arrestin gene promoter.

X-arrestin (arrestin-3) is an arrestin present specifically in the outer segments of red-, green-, and blue-cone photoreceptors. The X-arrestin gene is on Xcen-q22, and consists of 17 exons with a promoter containing a TATA box and elements important for photoreceptor expression, including three CRX and one PCE-1-like element. In order to delineate the promoter structure necessary for the pan-cone-specific expression of X-arrestin, the expression of the gene in retinoblastoma cell lines was investigated, and a structure-function analysis of the promoter was conducted in the appropriate cellular substrate. Expression of X-arrestin was detected at a low level in the Y79 retinoblastoma cell line but not in the WERI retinoblastoma cell line. Truncation and expression analysis of the X-arrestin promoter in Y79 showed maximal activity in the proximal 378-bp region containing the CRX and PCE-1-like elements upstream of the TATA and CAAT boxes and a negative regulator in the distal 1-2-kbp region. Mutagenesis of the three CRX and PCE-1-like elements and expression analysis demonstrated complete elimination of the promoter activity. Mutagenesis of the TATA box and PCE-1-like element individually resulted in similar decrease in promoter activity, but the decrease in the promoter activity was greater when the CRX elements were mutagenized with a 5' to 3' spatial gradient in the negative effect, suggesting a cooperative effect of the three CRX elements. The regulation of expression from this promoter may involve the binding of a multi-protein enhanceosome complex at the CRX triplet and the PCE-1-like element, resulting in the recruitment and activation of the RNA polymerase II complex at the downstream TATA box.

Mutations in the membrane component, chromosome 1, surface marker 1 (M1S1) gene in gelatinous drop-like corneal dystrophy.

PURPOSE: To report mutations in the membrane component, chromosome 1, surface marker 1 ( M1S1) gene in two members of the same family who showed symptoms of gelatinous drop-like corneal dystrophy (GDLD). METHODS: DNA was extracted from leukocytes of peripheral blood of the two affected members of the family and from controls, and the coding region of M1S1 was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by direct sequencing. Normal and mutant M1S1 expression vectors were constructed and transfected into CHO cells to identify the cellular location of the gene products. RESULTS: The affected members had compound heterozygous mutations consisting of a nonsense change at codon 84 (K84X) and a missense mutation resulting in a substitution of arginine for cysteine at codon 108 (C108R). Neither of these mutations was found in the 50 controls. Protein expression analysis showed that the C108R product was distributed diffusely in the cytoplasm, whereas the normal gene product accumulated at cell-to-cell adhesion borders. CONCLUSION: These data indicate that the K84X and C108R mutations in M1S1 cause GDLD.

Analysis of COL8A2 gene mutation in Japanese patients with Fuchs' endothelial dystrophy and posterior polymorphous dystrophy.

PURPOSE: To determine whether Japanese patients with Fuchs' endothelial corneal dystrophy (FECD) and posterior polymorphous dystrophy (PPMD) carry mutations in the COL8A2 gene, and to investigate the possible pathogenicity of the COL8A2 gene in these corneal dystrophies. METHODS: DNA analysis of the COL8A2 gene was performed in 15 unrelated Japanese patients with FECD, and 5 patients with PPMD using polymerase chain reaction and direct sequencing. Mutation screenings were also performed in 36 unrelated normal volunteers as controls, as well as slit-lamp and specular microscopy. RESULTS: Two types of heterozygous missense mutations of the COL8A2 gene (R155Q and T502M) in 5 of 15 FECD probands (R155Q, 3/30 chromosomes, 10.0%; T502M, 3/30 chromosomes, 10.0%) were found. No mutation was detected in the coding region of the COL8A2 gene in the remaining 10 patients with FECD nor in any of the 5 patients with PPMD. These two mutations were also found in normal Japanese volunteers (R155Q, 5/72 chromosomes, 6.9%; T502M, 11/70 chromosomes, 15.7%). The chromosomal frequency of the two mutations was not significant between the patients and normal controls. CONCLUSIONS: The R155Q and T502M mutations of COL8A2 may not be the causative defect in the Japanese FECD and PPMD patients examined in this study.

Compound heterozygous mutations of M1S1 gene in gelatinous droplike corneal dystrophy.

PURPOSE: To report the genetic findings in a Chinese patient diagnosed with gelatinous droplike corneal dystrophy (GDLD). DESIGN: Case report and experimental study. METHODS: Molecular genetic analysis was performed on the DNA extracted from peripheral leukocytes from a Chinese patient with GDLD and his unaffected parents. Fifty healthy, unrelated, Chinese participants were used as control subjects. The M1S1 gene was amplified by polymerase chain reaction and directly sequenced. RESULTS: The patient was clinically diagnosed with GDLD. Direct sequencing of the M1S1 gene revealed heterozygous changes in both alleles, a novel Y184C mutation on one allele and a Q118X mutation on the other that was reported as a founder mutation in the Japanese population. The patient's unaffected parents showed only the heterozygous Q118X or Y184C mutation. The mutation was not detected in the 50 unaffected subjects. CONCLUSIONS: This is the first genetic analysis of a Chinese patient with GDLD. Because the compound heterozygote mutations Q118X and Y184C cosegregated with the phenotype, they are likely the cause of GDLD in this patient.

Bietti crystalline corneoretinal dystrophy is caused by mutations in the novel gene CYP4V2.

Bietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessive retinal dystrophy characterized by multiple glistening intraretinal crystals scattered over the fundus, a characteristic degeneration of the retina, and sclerosis of the choroidal vessels, ultimately resulting in progressive night blindness and constriction of the visual field. The BCD region of chromosome 4q35.1 was refined to an interval flanked centromerically by D4S2924 by linkage and haplotype analysis; mutations were found in the novel CYP450 family member CYP4V2 in 23 of 25 unrelated patients with BCD tested. The CYP4V2 gene, transcribed from 11 exons spanning 19 kb, is expressed widely. Homology to other CYP450 proteins suggests that CYP4V2 may have a role in fatty acid and steroid metabolism, consistent with biochemical studies of patients with BCD.

Mutation analysis of the TGFBI gene in Vietnamese with granular and Avellino corneal dystrophy.

PURPOSE: Mutations of the human transforming growth factor beta-induced gene (TGFBI) were reported to cause granular (GCD) and Avellino (ACD) corneal dystrophy in various nationalities. In this study we examined the TGFBI gene in a Vietnamese population with GCD and ACD. METHODS: Eight unrelated Vietnamese families, including 20 affected and 24 unaffected individuals, were examined; 50 normal Vietnamese individuals were used as controls. Genomic DNA was extracted from peripheral blood leukocytes. The TGFBI gene was analyzed using the polymerase chain reaction and direct sequencing. The corneal button was studied. RESULTS: Slit-lamp examination revealed typical features of GCD in most cases. A few features of ACD and a patient with an atypical form of GCD were also seen. Histopathological analysis of a GCD cornea showed deposits that stained bright red with Masson trichrome. Sequencing revealed three distinct mutations: R555W in six families, R124H in one family, and D123H in another. CONCLUSIONS: R555W and R124H mutations were co-segregated with the disease phenotype and thus caused GCD and ACD, respectively, in the families studied. The R555W detected in six of the eight families indicates that the GCD phenotype may be the most common in Vietnamese individuals, unlike in other Asians (Japanese and Korean), where ACD is most common (>90%). The D123H mutation may cause an atypical variant of GCD.

Long-term follow-up for bullous keratopathy after sato-type anterior-posterior corneal refractive surgery.

PURPOSE: To evaluate cases of bullous keratopathy resulting from anterior-posterior radial corneal keratotomy (Sato-type operation) performed from 1951 to 1959. DESIGN: Observational case series. METHODS: Records for a total of 220 eyes of 139 patients with follow-up examinations were examined. The age at operation vs time to occurrence of bullous keratopathy after the original operation was evaluated in four age groups. Endothelial cell density was measured in 11 long-term postoperative eyes. RESULTS: The mean time to development of bullous keratopathy after surgery was 26.9 +/- 8.8 years (mean +/- SD; n = 173 eyes). The length of this period was not affected by the age of the patient at the time of the original surgery. Average endothelial cell density in 11 eyes of 11 patients 28.5 +/- 3.7 years after surgery was 639 +/- 135 cells/mm(2). CONCLUSIONS: Although some corneas remained clear more than 26 years after anterior-posterior radial keratotomy, the risk of late corneal decompensation continues to exist for these patients.

OPA1 gene mutations in Japanese patients with bilateral optic atrophy unassociated with mitochondrial DNA mutations at nt 11778, 3460, and 14484.

PURPOSE: To report mutations in the OPA1 gene in Japanese patients with bilateral optic atrophy unassociated with mitochondrial DNA mutations at nt 11778, 3460, and 14484. METHODS: Twelve unrelated patients with bilateral optic atrophy and 100 healthy controls were examined. Each exon of the OPA1 gene was amplified by polymerase chain reaction (PCR). All PCR products were sequenced. RESULTS: Of the 12 patients, 2 had nonsense mutations of the OPA1 gene (nt 1039G --> T and nt 1096C --> T, leading to Glu347Stop and Arg366Stop, respectively). These nonsense mutations were not found in the 100 healthy controls. Two of the patients had silent mutations of OPA1 gene (nt 1177T --> G and nt 1923G --> A causing no amino acid change). CONCLUSIONS: The mutations (Glu347Stop and Arg366Stop) of the OPA1 gene are involved in the pathogenesis of bilateral optic atrophy in Japanese patients.

Mutations in the CHST6 gene in patients with macular corneal dystrophy: immunohistochemical evidence of heterogeneity.

PURPOSE: Macular corneal dystrophy (MCD) is an autosomal recessive disorder leading to severe visual impairment. The carbohydrate sulfotransferase 6 (CHST6) gene, which encodes the corneal N-acetylglucosamine 6-O-sulfotransferase on 16q22 has been identified as a causative gene for MCD. The purpose of this study was to identify mutations in CHST6 in Japanese patients with MCD and evaluate them by means of immunohistochemistry. METHODS: CHST6 was screened in 7 patients and 45 healthy control subjects. Genomic DNA was isolated, and the open reading frame (ORF) of CHST6 was amplified by polymerase chain reaction (PCR). PCR products were analyzed by direct sequencing and restriction enzyme digestion. Immunohistochemistry with a monoclonal anti-keratan sulfate (KS) antibody was performed on corneas of four patients from three families. RESULTS: Three novel mutations (P204Q, R205L, and R177H) and two previously reported mutations (R211W and A217T) were identified in the ORF of CHST6. P204Q, R205L, and R211W were found to be homozygous and R177H and A217T compound heterozygous with R211W on another allele. Immunohistochemistry revealed that R205L homozygous cornea had negative reactivity against the anti-KS antibody, representing type I MCD, and that R211W homozygous and R211W/A217T compound heterozygous corneas had negative or very weak reactivity in the stroma with antibody positive deposits, which were distinct from any previously reported types. CONCLUSIONS: Two mutations (homozygoous R211W and compound heterozygous R211W/A217T) should be subclassified immunohistochemically into new phenotypes of MCD. This heterogeneity could provide further insights into the pathogenesis of MCD.

Mutation analysis of the carbohydrate sulfotransferase gene in Vietnamese with macular corneal dystrophy.

PURPOSE: Mutations in a new carbohydrate sulfotransferase gene (CHST6) encoding corneal N-acetylglucosamine-6-sulfotransferase (C-GlcNac-6-ST) have been identified as the cause of macular corneal dystrophy (MCD) in various ethnicities. This study was conducted to examine the CHST6 gene in Vietnamese with MCD. METHODS: Nineteen unrelated families, including 35 patients and 38 unaffected relatives were examined clinically. Blood samples were collected. Fifty normal Vietnamese individuals served as control subjects. Genomic DNA was extracted from leukocytes. Analysis of the CHST6 gene was performed with polymerase chain reaction and direct sequencing. Corneal buttons were studied histopathologically. RESULTS: A slit lamp examination revealed clinical features of MCD with gray-white opacities and stromal haze between. On histopathology, corneal sections showed positive staining with colloidal iron. Sequencing of the CHST6 gene revealed six homozygous and three compound heterozygous mutations. The homozygous mutations, including L59P, V66L, R211Q, W232X, Y268C, and 1067-1068ins(GGCCGTG) were detected, respectively, in two, one, eight, one, one, and two families. Compound heterozygous mutations R211Q/Q82X, S51L/Y268C, and Y268C/1067-1068ins(GGCCGTG) were identified, each in one family. A single heterozygous change at codon 76 (GTG-->ATG) was detected in family L, resulting in a valine-to-methionine substitution (V76M). None of these mutations was detected in the control group. CONCLUSIONS: Mutations identified in the CHST6 gene cosegregated with the disease phenotype in all but one family studied and thus caused MCD. Among these, the R211Q detected in 9 of 19 families may be the most common mutation in Vietnamese. These data also indicate that significant allelic heterogeneity exists for MCD.