Intraocular Pressure in Eyes with Intraocular Lens Dislocation and Pseudoexfoliation Syndrome.

PURPOSE: To investigate intraocular pressure in eyes with intraocular lens subluxation and pseudoexfoliation syndrome. METHODS: In this retrospective study conducted at one eye centre (tazz) in Zurich, Switzerland, we reviewed 85 eyes with intraocular lens subluxation and pseudoexfoliation syndrome. Intraocular lens exchange was carried out by two surgeons between 03/2016 and 12/2019 (45 months). Information on baseline characteristics and diagnosis of glaucoma was recorded. Intraocular pressure and best-corrected visual acuity were analysed preoperatively and at five time points up to 12 months after lens exchange. Data on antiglaucomatous medication was collected before surgery and at two different time points after surgery. Postoperative pressure lowering procedures and complications were further analysed. RESULTS: This study includes 85 pseudoexfoliation eyes with intraocular lens subluxation. The mean interval between cataract surgery and lens exchange was 8.9 ± 5.2 years. Intraocular pressure elevation in the event of intraocular lens subluxation was found in 54% (46/85) of eyes. Mean intraocular pressure decreased from 22.9 ± 9.4 mmHg preoperatively to 15.2 ± 3.4 mmHg at follow-up 12 months after lens exchange (p < 0.001). Postoperative topical antiglaucomatous drug requirements were comparable to preoperative levels (p = 0.520). Less systemic acetazolamide was required 12 months postoperatively (p = 0.018). A pressure lowering procedure was required in seven (8%) eyes in the postoperative period due to persistence of high intraocular pressure. Intermittent increase or persistence of high intraocular pressure occurred in 13 (15%) eyes. CONCLUSION: This study emphasises the connection between acute pressure elevation and intraocular lens subluxation in patients with pseudoexfoliation syndrome. Intraocular pressure decreases after lens exchange and decrease sustains for a postoperative period of 12 months. Postoperative pressure lowering procedures were not required in the majority of eyes. We therefore conclude that intraocular lens exchange is efficient in the management of lens subluxation and pressure elevation in patients with pseudoexfoliation syndrome.

Two Surgical Approaches for Intraocular Lens Dislocation: Pars Plana Vitrectomy Versus Core Vitrectomy with Lens Exchange.

PURPOSE: To compare the efficacy and safety of core vitrectomy and pars plana vitrectomy for lens exchange in patients with intraocular lens dislocation. METHODS: This is a retrospective study conducted at one eye center in Zurich, Switzerland. We reviewed 124 eyes with dislocated intraocular lens undergoing lens exchange carried out by two surgeons between 03/2016 and 12/2019 (45 months). Intraocular pressure (IOP) and best-corrected visual acuity (BCVA) were analyzed preoperatively and at 5 time points up to 12 months after lens exchange. Data on postoperative complications were collected. RESULTS: There were 124 eyes with intraocular lens dislocation that were referred for lens exchange. Of these eyes, 59 (48%) received core vitrectomy and 65 (52%) received pars plana vitrectomy with lens exchange. Glaucoma was more frequent in the core vitrectomy group (78%) than in the pars plana vitrectomy group (32%; p < 0.001). In the core vitrectomy group, 19 (32%) eyes presented with visual impairment, 17 (29%) eyes presented with high IOP alone, and 23 (39%) eyes presented with both at the same time prior to surgery. Mean preoperative IOP in the core vitrectomy group decreased from 22.4 ± 9.2 mmHg to 14.7 ± 3.1 mmHg 12 months after surgery (p < 0.001). Mean BCVA changed from 0.40 ± 0.41 logMAR preoperatively to 0.32 ± 0.37 logMAR at 12 months postoperatively (p = 0.598) in the core vitrectomy group. In the pars plana vitrectomy group, 44 (68%) eyes presented with a change in vision, 7 (11%) eyes presented with high IOP alone, and 14 (22%) eyes presented with pressure elevation and visual impairment at the visit prior to surgery. Mean preoperative IOP in the pars plana vitrectomy group decreased from 20.9 ± 8.3 mmHg to 15.1 ± 3.5 mmHg at 12 months after lens exchange (p < 0.001). Mean BCVA in the pars plana vitrectomy group was 0.57 ± 0.62 logMAR preoperatively and 0.22 ± 0.35 logMAR 12 months postoperatively (p < 0.001). Postoperative pressure decompensation occurred more frequently in the core vitrectomy group (20%) than in the pars plana vitrectomy group (6%; p = 0.018). There was no statistically significant difference for postoperative cystoid macular edema (p = 0.055), anisometropia (p = 0.986), and high astigmatism (p = 0.362). CONCLUSION: Core vitrectomy and pars plana vitrectomy with lens exchange are equally efficient and safe in the management of intraocular lens dislocation.

Peripheral Inflammatory Yellow Exudative Retinal Coats-Like Vitreoretinopathy Misdiagnosed as Acute Retinal Necrosis in a Retinitis Pigmentosa Patient after Cataract Surgery.

We would like to describe a case with Coats-like exudative vitreoretinopathy after cataract surgery in a patient with retinitis pigmentosa (RP) misdiagnosed as acute retinal necrosis (ARN). A patient with RP underwent cataract surgery that was complicated by macular oedema. Following sub-Tenon's injection of triamcinolone acetonide, evolution was initially favourable. However, 2 months later, after 2 sub-Tenon's injections, the patient complained again of floaters and a drop of visual acuity. Aqueous flare measured by laser flare photometry was increased and posterior segment examination showed vitreitis, posterior haemorrhages and a temporal-inferior peripheral white-yellowish area in left eye. Serology (IgGs) for varicella-zoster virus (VZV) was slightly elevated and more so for toxoplasmosis. The whole clinical context strongly evoked ARN not excluding completely ocular toxoplasmosis. Valacyclovir and clindamycin were introduced without benefit. When examining the extreme periphery of the right fellow eye, discreet yellow lesions were also detected rendering the infectious hypothesis less probable. A vitrectomy finally excluded infectious causes and the diagnosis of Coats-like exudative vitreoretinopathy in a RP patient was retained. Increased flare despite 2 sub-Tenon's injections, the presence of micro-haemorrhages, and peripheral yellow retinal necrotic areas drew our attention away from a well-known albeit rare condition of Coats-like response in RP patients, a diagnosis which has to be considered in such circumstances.

Identification of Novel and Recurrent Disease-Causing Mutations in Retinal Dystrophies Using Whole Exome Sequencing (WES): Benefits and Limitations.

Inherited retinal dystrophies (IRDs) are Mendelian diseases with tremendous genetic and phenotypic heterogeneity. Identification of the underlying genetic basis of these dystrophies is therefore challenging. In this study we employed whole exome sequencing (WES) in 11 families with IRDs and identified disease-causing variants in 8 of them. Sequence analysis of about 250 IRD-associated genes revealed 3 previously reported disease-associated variants in RHO, BEST1 and RP1. We further identified 5 novel pathogenic variants in RPGRIP1 (p.Ser964Profs*37), PRPF8 (p.Tyr2334Leufs*51), CDHR1 (p.Pro133Arg and c.439-17G>A) and PRPF31 (p.Glu183_Met193dup). In addition to confirming the power of WES in genetic diagnosis of IRDs, we document challenges in data analysis and show cases where the underlying genetic causes of IRDs were missed by WES and required additional techniques. For example, the mutation c.439-17G>A in CDHR1 would be rated unlikely applying the standard WES analysis. Only transcript analysis in patient fibroblasts confirmed the pathogenic nature of this variant that affected splicing of CDHR1 by activating a cryptic splice-acceptor site. In another example, a 33-base pair duplication in PRPF31 missed by WES could be identified only via targeted analysis by Sanger sequencing. We discuss the advantages and challenges of using WES to identify mutations in heterogeneous diseases like IRDs.

Next generation sequencing based identification of disease-associated mutations in Swiss patients with retinal dystrophies.

Inherited monogenic diseases of the retina and vitreous affect approximately 1 in 2000 individuals. They are characterized by tremendous genetic heterogeneity and clinical variability involving mutations in approximately 250 genes and more than 20 different clinical phenotypes. Clinical manifestations of retinal dystrophies (RDs) range from mild retinal dysfunctions to severe congenital forms of blindness. A detailed clinical diagnosis and the identification of causative mutations are crucial for genetic counseling of affected patients and their families, for understanding genotype-phenotype correlations and developing therapeutic approaches. Using whole exome sequencing (WES) we have established a reliable and efficient high-throughput analysis pipeline to identify disease-causing mutations. Our data indicate that this approach enables us to genetically diagnose approximately 64% of the patients (n = 58) with variant(s) in known disease-associated genes. We report 20 novel and 26 recurrent variants in genes associated with RDs. We also identified a novel phenotype for mutations in C2orf71 and provide functional evidence for exon skipping due to a splice-site variant identified in FLVCR1. In conclusion, WES can rapidly identify variants in various families affected with different forms of RDs. Our study also expands the clinical and allelic spectrum of genes associated with RDs in the Swiss population.

Impact of loading phase, initial response and CFH genotype on the long-term outcome of treatment for neovascular age-related macular degeneration.

OBJECTIVE: Factors influencing the outcome of anti-VEGF treatment in neovascular AMD are still investigated. We analyzed the impact of a loading phase, the significance of an initial response for the long-term and the effect of the CFH polymorphism (p.His402Tyr) on treatment outcome. METHODS: Patients treated with ranibizumab for neovascular AMD were analyzed over a period of 24 months by assessing effects of loading phase, initial response and genotype of CFH rs1061170 (c.1204C>T, p.His402Tyr). RESULTS: 204 eyes were included. A change of +5.0 [-1;+11] letters and +1.5 [-5.5;+9.5] was observed with a median of 4 [3]; [7] and 10 [7]; [14] ranibizumab injections during 12 and 24 months, respectively. Loading phase was no significant predictor for treatment as VA outcome in eyes with and without loading phase was similar (p = 0.846 and p = 0.729) at 12 and 24 months. In contrast, initial response was a significant predictor for improving vision of 5 or more letters at 12 (p = 0.001; OR = 6.75) and 24 months (p = 0.01; OR = 4.66). Furthermore, the CT genotype at CFH rs1061170 was identified as a significant predictor for a favorable VA outcome at 12 and 24 months (OR = 6.75, p = 0.001 and OR = 4.66, p = 0.01). CONCLUSIONS: Our data suggest that clinical decisions regarding treatment may be guided by observing patients' initial response as well as their genotype of SNP rs1061170, while the criterion of loading phase may not bear the customary value.

Macrocephaly in neurofibromatosis type 1: a sign post for optic pathway gliomas?

PURPOSE: Optic pathway gliomas, which occur in 15-20% of paediatric patients with neurofibromatosis type 1, are the most common central nervous system tumour associated with this neurocutaneous disorder. The detection of optic pathway gliomas is essential for further management but is often delayed in infancy due to oligosymptomatic progression and difficulties in clinical detection. Therefore, the aim of our study was to find a clinical indicator for the presence of optic pathway gliomas in children with neurofibromatosis type 1 in order to facilitate early diagnosis and initiate further ophthalmological and neuroimaging investigations. METHODS: We retrospectively evaluated 70 patients (mean age of 10.5 years; SD of 4.3 years; range of 0.5-19.6 years; 35 females) with neurofibromatosis type 1 seen at the University Children's Hospital of Bern, Switzerland, between January 1998 and December 2008 regarding clinical features of neurofibromatosis type 1 in relation to the presence of optic pathway gliomas. RESULTS: Fifty-seven of the 70 patients (81.4%) had no clinical or radiological signs of optic pathway gliomas [magnetic resonance imaging (MRI) of the brain in 26/57], whereas 13/70 patients (18.6%) were diagnosed with optic pathway gliomas by MRI. Patients with optic pathway gliomas showed macrocephaly significantly more often compared to patients without optic pathway gliomas (8/13 vs. 9/57, respectively; p = 0.004). CONCLUSION: Macrocephaly significantly correlates with the incidence of optic pathway gliomas in children with neurofibromatosis type 1. We therefore hypothesise that in otherwise asymptomatic patients, macrocephaly is an additional indicator for performing MRI to detect optic pathway gliomas.

Genetic association with response to intravitreal ranibizumab in patients with neovascular AMD.

PURPOSE: Neovascular age-related macular degeneration (AMD) resulting in decreased central vision severely impairs affected individuals. Current standard treatment is an intravitreal anti-VEGF therapy (ranibizumab), but responses to treatment show large variability. Genetic factors that influence AMD and that affect the outcome of ranibizumab treatment were sought within a sample of Swiss patients. METHODS: Changes in visual acuity (VA) after initiation of anti-VEGF treatment were observed during 12 months, and percentiles of VA were calculated. Genotypes of polymorphisms in known AMD susceptibility loci (CFH, CFB, HTRA1, AMRS2, and VEGFA) as well as not yet reported AMD-associated genes (KDR, LRP5, and FZD4) were determined, and their frequencies were compared. RESULTS: Of the 309 eyes included in the study, 243 completed VA assessment. On average, 3.9 ±2.6 ranibizumab injections were administered. Based on the change in visual acuity, two responder groups were established: 63 eyes were assigned to the poor responders (≤25th percentile) and 63 eyes to the good responders (≥75th percentile). Individuals with genotype CC of p.Y402H in CFH had a decreased chance of positive treatment outcome compared with those with the CT and TT genotypes (P = 0.005 and P = 0.006). In this study, the genotype combination of AG at CFH with CT at FZD4 (SNP rs10898563) promised an increased chance of positive treatment outcome (P = 0.004). Furthermore, the association with the known genetic susceptibility loci CFH, HTRA1, and AMRS2 were confirmed, and a risk-conferring polymorphism in one new locus, LRP5, was identified. CONCLUSIONS: Genetic predisposition may account for the variability in response to anti-VEGF treatment.

Mechanical properties of bare and protein-coated giant unilamellar phospholipid vesicles. A comparative study of micropipet aspiration and atomic force microscopy.

In this study, protein-coated giant phospholipid vesicles were used to model cell plasma membranes coated by surface protein layers that increase membrane stiffness under mechanical or osmotic stress. These changed mechanical properties like bending stiffness, membrane area compressibility modulus, and effective Young's modulus were determined by micropipet aspiration, while bending stiffness, effective Young's modulus, and effective spring constant of vesicles were analyzed by AFM. The experimental setups, the applied models, and the results using both methods were compared here. As demonstrated before, we found that bare vesicles were best probed by micropipet aspiration due to its high sensitivity. The mechanical properties of vesicles with protein surface layers were, however, better determined by AFM because it enables very local deformations of the membrane with barely any structural damage to the protein layer. Mechanical properties of different species of coating proteins, here streptavidin and avidin, could be clearly distinguished using this technique.

Genotyping microarray for CSNB-associated genes.

PURPOSE: Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous retinal disease. Although electroretinographic (ERG) measurements can discriminate clinical subgroups, the identification of the underlying genetic defects has been complicated for CSNB because of genetic heterogeneity, the uncertainty about the mode of inheritance, and time-consuming and costly mutation scanning and direct sequencing approaches. METHODS: To overcome these challenges and to generate a time- and cost-efficient mutation screening tool, the authors developed a CSNB genotyping microarray with arrayed primer extension (APEX) technology. To cover as many mutations as possible, a comprehensive literature search was performed, and DNA samples from a cohort of patients with CSNB were first sequenced directly in known CSNB genes. Subsequently, oligonucleotides were designed representing 126 sequence variations in RHO, CABP4, CACNA1F, CACNA2D4, GNAT1, GRM6, NYX, PDE6B, and SAG and spotted on the chip. RESULTS: Direct sequencing of genes known to be associated with CSNB in the study cohort revealed 21 mutations (12 novel and 9 previously reported). The resultant microarray containing oligonucleotides, which allow to detect 126 known and novel mutations, was 100% effective in determining the expected sequence changes in all known samples assessed. In addition, investigation of 34 patients with CSNB who were previously not genotyped revealed sequence variants in 18%, of which 15% are thought to be disease-causing mutations. CONCLUSIONS: This relatively inexpensive first-pass genetic testing device for patients with a diagnosis of CSNB will improve molecular diagnostics and genetic counseling of patients and their families and gives the opportunity to analyze whether, for example, more progressive disorders such as cone or cone-rod dystrophies underlie the same gene defects.

Therapeutic strategy to rescue mutation-induced exon skipping in rhodopsin by adaptation of U1 snRNA.

Retinitis pigmentosa (RP) is a degenerative retinopathy leading to visual impairment in more than 1.5 million patients worldwide. Splice site (SS) mutations cause various diseases including RP. Most exonic donor splice-site (DS) mutations are reported at the last nucleotide of an exon and over 95% of them are predicted to result in missplicing. A novel human mutation at the last nucleotide of exon 4 in rhodopsin (RHO, c.936G>A) is shown to generate two misspliced transcripts in COS 7 cells and retinal explants. One of these transcripts skips exon 4 whereas the other activates a cryptic DS. Both are predicted to result in truncated RHO, explaining the pathogenic mechanism underlying the patient's RP phenotype. U1 snRNA-mediated DS recognition is a key step in the splicing process. As a therapeutic strategy, U1 snRNAs were adapted to the novel RHO mutation and tested for its potential to reverse missplicing. The rescue efficiency for misspliced transcripts of RHO was examined by quantitative RT-PCR. Using mutation-adapted U1 snRNA, we observed significantly reduced exon skipping that reached wild-type levels. Nevertheless, activation of the cryptic splice site (CS) was still detected. To test the feasibility of the strategy for mutations that only cause exon skipping, we inactivated the CS. Indeed, adapted U1 snRNA was able to rescue almost 95% [corrected] of misspliced transcripts. This study shows that modified U1 snRNAs constitute a promising therapeutic strategy to treat DS mutations. Our findings have implications for various diseases caused by similar mutations.

Treatment of branch retinal vein occlusion induced macular edema with bevacizumab.

BACKGROUND: Branch retinal vein occlusion is a frequent cause of visual loss with currently insufficient treatment options. We evaluate the effect of Bevacizumab (Avastin) treatment in patients with macular edema induced by branch retinal vein occlusion. METHODS: Retrospective analysis of 32 eyes in 32 patients with fluorescein angiography proven branch retinal vein occlusion, macular edema and Bevacizumab treatment. Outcome measures were best corrected visual acuity in logMAR and central retinal thickness in OCT. RESULTS: Visual acuity was significantly better 4 to 6 weeks after Bevacizumab treatment compared to visual acuity prior to treatment (before 0.7 +/- 0.3 and after 0.5 +/- 0.3; mean +/- standard deviation; p < 0.01, paired t-test). Gain in visual acuity was accompanied by a significant decrease in retinal thickness (454 +/- 117 to 305 +/- 129 microm, p < 0.01, paired t-test). Follow up (170, 27 - 418 days; median, range) shows that improvement for both visual acuity and retinal thickness last for several months after Bevacizumab use. CONCLUSION: We present evidence that intravitreal Bevacizumab is an effective and lasting treatment for macular edema after branch retinal vein occlusion.

Identification of novel mutations in X-linked retinitis pigmentosa families and implications for diagnostic testing.

PURPOSE: The goal of this study was to identify mutations in X-chromosomal genes associated with retinitis pigmentosa (RP) in patients from Germany, The Netherlands, Denmark, and Switzerland. METHODS: In addition to all coding exons of RP2, exons 1 through 15, 9a, ORF15, 15a and 15b of RPGR were screened for mutations. PCR products were amplified from genomic DNA extracted from blood samples and analyzed by direct sequencing. In one family with apparently dominant inheritance of RP, linkage analysis identified an interval on the X chromosome containing RPGR, and mutation screening revealed a pathogenic variant in this gene. Patients of this family were examined clinically and by X-inactivation studies. RESULTS: This study included 141 RP families with possible X-chromosomal inheritance. In total, we identified 46 families with pathogenic sequence alterations in RPGR and RP2, of which 17 mutations have not been described previously. Two of the novel mutations represent the most 3'-terminal pathogenic sequence variants in RPGR and RP2 reported to date. In exon ORF15 of RPGR, we found eight novel and 14 known mutations. All lead to a disruption of open reading frame. Of the families with suggested X-chromosomal inheritance, 35% showed mutations in ORF15. In addition, we found five novel mutations in other exons of RPGR and four in RP2. Deletions in ORF15 of RPGR were identified in three families in which female carriers showed variable manifestation of the phenotype. Furthermore, an ORF15 mutation was found in an RP patient who additionally carries a 6.4 kbp deletion downstream of the coding region of exon ORF15. We did not identify mutations in 39 sporadic male cases from Switzerland. CONCLUSIONS: RPGR mutations were confirmed to be the most frequent cause of RP in families with an X-chromosomal inheritance pattern. We propose a screening strategy to provide molecular diagnostics in these families.

Impact of optic media opacities and image compression on quantitative analysis of optical coherence tomography.

PURPOSE: To analyze the impact of opacities in the optical pathway and image compression of 32-bit raw data to 8-bit jpg images on quantified optical coherence tomography (OCT) image analysis. METHODS: In 18 eyes of nine healthy subjects, OCT images were acquired from the central macula. To simulate opacities in the optical system, neutral-density (ND) filters with linear absorption spectra were placed between the OCT device and examined eyes. Light reflection profiles (LRPs) of images acquired with various ND filters were compared. LRPs of the 32-bit raw data were compared with those obtained from the 8-bit jpg compressed images. RESULTS: ND filters induced a linear decrease of reflectivity in OCT images, depending on initial signal intensity. Quantitative OCT analysis showed no significant difference between 32-bit raw data and 8-bit jpg files (P > 0.05). CONCLUSIONS: Quantitative OCT analysis is not significantly influenced by data compression. A mathematical model can correct for optical opacities to improve OCT images.

A new method to monitor visual field defects caused by photoreceptor degeneration by quantitative optical coherence tomography.

PURPOSE: To correlate the dimension of the visual field (VF) tested by Goldman kinetic perimetry with the extent of visibility of the highly reflective layer between inner and outer segments of photoreceptors (IOS) seen in optical coherence tomography (OCT) images in patients with retinitis pigmentosa (RP). METHODS: In a retrospectively designed cross-sectional study, 18 eyes of 18 patients with RP were examined with OCT and Goldmann perimetry using test target I4e and compared with 18 eyes of 18 control subjects. A-scans of raw scan data of Stratus OCT images (Carl Zeiss Meditec, AG, Oberkochen, Germany) were quantitatively analyzed for the presence of the signal generated by the highly reflective layer between the IOS in OCT images. Starting in the fovea, the distance to which this signal was detectable was measured. Visual fields were analyzed by measuring the distance from the center point to isopter I4e. OCT and visual field data were analyzed in a clockwise fashion every 30 degrees , and corresponding measures were correlated. RESULTS: In corresponding alignments, the distance from the center point to isopter I4e and the distance to which the highly reflective signal from the IOS can be detected correlate significantly (r = 0.75, P < 0.0001). The greater the distance in VF, the greater the distance measured in OCT. CONCLUSIONS: The authors hypothesize that the retinal structure from which the highly reflective layer between the IOS emanates is of critical importance for visual and photoreceptor function. Further research is warranted to determine whether this may be useful as an objective marker of progression of retinal degeneration in patients with RP.

Identification and characterization of a novel RPGR isoform in human retina.

Retinitis pigmentosa (RP) constitutes a major cause of blindness and the Retinitis Pigmentosa GTPase Regulator (RPGR) gene accounts for up to 80% of all X-linked RP cases. A novel isoform of RPGR, expressed in the human retina, was identified and characterized. It truncates the Regulator of Chromosome Condensation 1 (RCC1) homologous protein domain (RCC1h) of RPGR and mediates the formation of isoform-specific complexes with the RPGR-interacting protein 1 (RPGRIP1). Immunohistochemistry localized the novel RPGR isoform predominantly to inner segments of cone photoreceptors, where it colocalizes with RPGRIP1 in the human retina. In a patient with a mild RP phenotype, we identified a nucleotide substitution in a splicing regulator, which leads to 3.5 times higher levels of the transcripts coding for the novel RPGR isoform. The nucleotide substitution affects regulated alternative splicing of the novel RPGR isoform and suggests a tight adjustment of splicing as a prerequisite for proper function of photoreceptors.

Is pseudophakia a risk factor for neovascular age-related macular degeneration?

PURPOSE: To examine the possible association between pseudophakia and neovascular age-related macular degeneration (AMD). METHODS: Reports of all patients undergoing fluorescein angiography in the authors' department over a 6-year period were retrospectively reviewed. Four hundred ninety-nine patients with recent onset of neovascular AMD in one eye and early age-related maculopathy (ARM) in the fellow eye were included in the study. Lens status (phakic or pseudophakic) in both eyes at the time of onset of neovascular AMD and the time between cataract surgeries (if performed) and onset of neovascular AMD were determined. RESULTS: There was no significant difference in lens status between eyes with neovascular AMD and fellow eyes with early ARM (115/499 [23.0%] vs. 112/499 [22.4%] pseudophakic; P = 0.88, odds ratio 1.035, 95% CI 0.770-1.391). Subgroup analysis revealed no difference between the groups with large drusen, small drusen, or pigmentary changes only (respectively, 20.3% vs. 19.6% pseudophakic, P = 0.92; 20.5% vs. 23.3% pseudophakic, P = 0.84; 33.3% vs. 31.7% pseudophakic, P = 1.0). Pseudophakic eyes with neovascular AMD had not been pseudophakic for a significantly longer period at the time of onset of neovascular AMD than their pseudophakic fellow eyes at the same time point (225.9 +/- 170.4 vs. 209.9 +/- 158.2 weeks, P = 0.27). CONCLUSIONS: The results do not support the hypothesis that pseudophakia is a major risk factor for the development of neovascular AMD.

Development of a genotyping microarray for Usher syndrome.

BACKGROUND: Usher syndrome, a combination of retinitis pigmentosa (RP) and sensorineural hearing loss with or without vestibular dysfunction, displays a high degree of clinical and genetic heterogeneity. Three clinical subtypes can be distinguished, based on the age of onset and severity of the hearing impairment, and the presence or absence of vestibular abnormalities. Thus far, eight genes have been implicated in the syndrome, together comprising 347 protein-coding exons. METHODS: To improve DNA diagnostics for patients with Usher syndrome, we developed a genotyping microarray based on the arrayed primer extension (APEX) method. Allele-specific oligonucleotides corresponding to all 298 Usher syndrome-associated sequence variants known to date, 76 of which are novel, were arrayed. RESULTS: Approximately half of these variants were validated using original patient DNAs, which yielded an accuracy of >98%. The efficiency of the Usher genotyping microarray was tested using DNAs from 370 unrelated European and American patients with Usher syndrome. Sequence variants were identified in 64/140 (46%) patients with Usher syndrome type I, 45/189 (24%) patients with Usher syndrome type II, 6/21 (29%) patients with Usher syndrome type III and 6/20 (30%) patients with atypical Usher syndrome. The chip also identified two novel sequence variants, c.400C>T (p.R134X) in PCDH15 and c.1606T>C (p.C536S) in USH2A. CONCLUSION: The Usher genotyping microarray is a versatile and affordable screening tool for Usher syndrome. Its efficiency will improve with the addition of novel sequence variants with minimal extra costs, making it a very useful first-pass screening tool.

Different amino acid substitutions at the same position in rhodopsin lead to distinct phenotypes.

PURPOSE: Identification of a novel rhodopsin mutation in a family with retinitis pigmentosa and comparison of the clinical phenotype to a known mutation at the same amino acid position. METHODS: Screening for mutations in rhodopsin was performed in 78 patients with retinitis pigmentosa. All exons and flanking intronic regions were amplified by PCR, sequenced, and compared to the reference sequence derived from the National Center for Biotechnology Information (NCBI, Bethesda, MD) database. Patients were characterized clinically according to the results of best corrected visual acuity testing (BCVA), slit lamp examination (SLE), funduscopy, Goldmann perimetry (GP), dark adaptometry (DA), and electroretinography (ERG). Structural analyses of the rhodopsin protein were performed with the Swiss-Pdb Viewer program available on-line (http://www.expasy.org.spdvbv/ provided in the public domain by Swiss Institute of Bioinformatics, Geneva, Switzerland). RESULTS: A novel rhodopsin mutation (Gly90Val) was identified in a Swiss family of three generations. The pedigree indicated autosomal dominant inheritance. No additional mutation was found in this family in other autosomal dominant genes. The BCVA of affected family members ranged from 20/25 to 20/20. Fundus examination showed fine pigment mottling in patients of the third generation and well-defined bone spicules in patients of the second generation. GP showed concentric constriction. DA demonstrated monophasic cone adaptation only. ERG revealed severely reduced rod and cone signals. The clinical picture is compatible with retinitis pigmentosa. A previously reported amino acid substitution at the same position in rhodopsin leads to a phenotype resembling night blindness in mutation carriers, whereas patients reported in the current study showed the classic retinitis pigmentosa phenotype. The effect of different amino acid substitutions on the three-dimensional structure of rhodopsin was analyzed by homology modeling. Distinct distortions of position 90 (shifts in amino acids 112 and 113) and additional hydrogen bonds were found. CONCLUSIONS: Different amino acid substitutions at position 90 of rhodopsin can lead to night blindness or retinitis pigmentosa. The data suggest that the property of the substituted amino acid distinguishes between the phenotypes.