Recessive mutations in the CYP4V2 gene in East Asian and Middle Eastern patients with Bietti crystalline corneoretinal dystrophy.

BACKGROUND: Bietti crystalline corneoretinal dystrophy (BCD) is an autosomal recessively inherited disorder characterised by tiny yellowish glittering retinal crystals, choroidal sclerosis, and crystals in the peripheral cornea, associated with progressive night blindness. CYP4V2, encoding a member of cytochrome p450 (CYP450) protein family, was recently identified as the causative gene. METHODS: We recruited 11 unrelated patients with BCD and characteristic clinical features; eight of Japanese, two of Middle Eastern, and one of Chinese ancestry. Genomic DNA was extracted from peripheral blood leucocytes, and all 11 exons and the flanking intron splice sites of the CYP4V2 gene were amplified and sequenced. A complete ophthalmological examination was performed. RESULTS: We found recessive mutations in the CYP4V2 gene in all of the 11 patients. Two novel mutations, L173W and Q450X, were identified in a Japanese patient and two unrelated patients from Middle Eastern countries, respectively. Each patient was a homozygote. A previously reported mutation IVS6-8_810delinsGC was identified in seven unrelated Japanese patients and the Chinese patient with BCD. All patients with BCD shared a characteristic fundus appearance with numerous intraretinal crystal deposits and atrophy of the retinal pigment epithelium. However, the clinical findings, including elecroretinograph recordings, indicated that there was considerable variation in the degree of visual dysfunction even among patients of similar ages carrying the same mutation. CONCLUSIONS: Defects in CYP4V2 are the main cause of BCD. The IVS6-8_810delinsGC mutant allele may be especially prevalent among patients with BCD in East Asian countries, resulting from a single founder. Variation of disease severity suggests that environmental or additional genetic factors influence the course of the retinal disease.

Histopathology of explanted collar button keratoprostheses: a clinicopathologic correlation.

PURPOSE: To compare the histopathology of three PMMA collar button type keratoprosthesis (KPro)/corneal specimens, explanted due to various complications, with that from one KPro/corneal specimen taken postmortem from an otherwise "healthy" enucleated eye. METHODS: Patient 1 (chemical injury) had no problems for 3 years after KPro placement; the entire eye was obtained postmortem. Patient 2 (repeated graft failures, nonautoimmune disease) developed an "unlaserable" retroprosthesis membrane 4 months after KPro placement. A new KPro was placed. Patient 3 [ocular cicatricial pemphigoid (OCP)] developed tissue melt at the KPro-cornea interface 7 months after KPro placement, and the KPro was replaced. Patient 4 (OCP) developed progressive corneal melt around the KPro 3.5 years after placement resulting in replacement. All KPro/cornea specimens were processed and sectioned for histology with the KPro in place. RESULTS: All patients exhibited growth of corneal or conjunctival derived epithelium under the KPro front plate. In patients 1 and 2, no epithelial downgrowth was noted and the keratocyte density appeared normal with few inflammatory cells present. Dense fibrous tissue was present behind the KPro in patient 2. Patients 3 and 4 showed massive inflammatory cell infiltration and tissue necrosis with "melt" adjacent to the stem resulting in epithelial downgrowth. CONCLUSIONS: Corneal inflammation and degradation after KPro placement correlate well with the preoperative diagnostic category. Patients with immune-related corneal surface disease can exhibit marked inflammatory responses leading to necrosis, stromal melting, and the formation of an epithelial fistula. In contrast, patients without autoimmune corneal disease demonstrate a remarkably noninflamed cornea with intact keratocytes and without epithelial ingrowth, commensurate with their clinical appearance.

Dominant Leber congenital amaurosis, cone-rod degeneration, and retinitis pigmentosa caused by mutant versions of the transcription factor CRX.

We summarize 18 mutations in the human CRX gene that have been associated with Leber congenital amaurosis (congenital retinal blindness), cone-rod degeneration, or retinitis pigmentosa. Except for one obviously null allele not definitely associated with a phenotype (a frameshift in codon 9), all CRX mutations appear to be completely penetrant and cause disease in heterozygotes. These dominant alleles fall into two categories. In one group are missense mutations and short, in-frame deletions; in the second group are frameshift mutations, all of which are in the last exon. All of these dominant mutations are likely to produce stable mRNA that is translated. Mutations in the missense group preferentially affect the conserved homeobox (codons 39-98), and all frameshift mutations leave the homeodomain intact but alter the OTX motif encoded by codons 284-295 at the carboxy terminus. We could not uncover any correlation between type of disease (congenital amaurosis vs. cone-rod degeneration or retinitis pigmentosa) and the type of mutation (missense vs. frameshift). Four of the 18 mutations (approximately 20%) were de novo mutations, and all of these were found in isolate cases of Leber congenital amaurosis. Dominant CRX mutations have not been associated with mental retardation or developmental delay that has sometimes been found in Leber congenital amaurosis caused by other genes. Implications regarding potential future therapies are discussed.

Novel frameshift mutations in CRX associated with Leber congenital amaurosis.

Mutations in CRX, a photoreceptor-specific transcription factor, can cause Leber congenital amaurosis (LCA), cone-rod dystrophy (CORD), and retinitis pigmentosa (RP), all of which feature severe visual impairment. Upon screening 55 patients with Leber congenital amaurosis, 75 patients with cone-rod dystrophy, 13 with cone dystrophy, and 36 with recessive or isolate RP for changes in the CRX sequence, we found two patients with Leber congenital amaurosis who carried heterozygously one of two novel frameshift mutations. The first mutation, Tyr191(1-bp del), was a de novo change and the second change, Pro263(1-bp del) was inherited from the proband's affected father. Both mutations are predicted to encode mutant versions of CRX with altered carboxy termini. We also found a previously reported missense mutation, Arg41Gln, heterozygously in a 47-year-old patient with a form of RP. The missense change Val242Met was found in an isolate case of CORD and no controls; however, its pathogenicity remains uncertain because only limited segregation analysis was possible. A nonpathogenic missense change, Ala158Thr, was found to be a variant present at relatively high frequency among African-Americans.

RB1 genetic testing as a clinical service: a follow-up study.

BACKGROUND: Genetic testing for inherited predisposition to diverse cancers has recently become available as a clinical service. We conducted a follow-up study of the initial series of US families who underwent RB1 genetic testing to evaluate long-term effects of the service. PROCEDURE: We enrolled 52 of 71 eligible families who responded to a follow-up study questionnaire administered 3-10 years after receipt of their RB1 results. Each family had one proband with unilateral, non-familial retinoblastoma, which is associated with a 12% pre-test probability of hereditary retinoblastoma. RB1 testing identified germline RB1 mutations in five patients, lowered the carrier probability to 2% in 21 patients, and did not substantially modify the carrier probability in the remaining 26. RESULTS: Diverse medical specialists offered and arranged for RB1 testing, and their recommendation was the most influential factor in the decision to be tested. Pre-test counseling was provided by ophthalmologists (30), oncologists (11), and geneticists and genetic counselors (11). Most respondents, regardless of test result, were satisfied and perceived gains from their genetic testing. Based on small numbers, families with reduced likelihood of hereditary retinoblastoma reported more positive outcomes. Parents of RB1 carriers were more likely to seek medical services, worry, and decide against having more children. CONCLUSIONS: This study demonstrates the feasibility of follow-up studies of families who had genetic testing. Results from our small series suggest that genetic information and counseling are important components of RB1 clinical genetic testing, and long-term adverse effects of testing are uncommon.

Clinical features and mutations in patients with dominant retinitis pigmentosa-1 (RP1).

PURPOSE: To survey patients with dominant retinitis pigmentosa (RP) for mutations in the RP1 gene to determine the spectrum of dominant mutations in this gene, to estimate the proportion of dominant RP caused by this gene, and to determine whether the clinical features of patients with RP1 mutations differ from features of those with rhodopsin mutations. METHODS: A set of 241 patients who did not have mutations in the rhodopsin gene (based on previous work) formed the basis for the study. Of these patients, 117 had also been previously evaluated and were found not to carry mutations in the RDS gene. The single-strand conformation polymorphism (SSCP) method was used to search for sequence variants, which were then directly sequenced. The relatives of selected patients were recruited for segregation analyses. Clinical evaluations of patients included a measurement of Snellen visual acuity, final dark adaptation thresholds, visual fields, and ERGs. Clinical data were compared with those obtained earlier from a study of 128 patients with dominant rhodopsin mutations. RESULTS: Of the 241 patients, all were screened for the most common RP1 mutation (Arg677Ter), and 10 patients were found to have this mutation. In addition, an evaluation of a subset of 189 patients in whom the entire coding sequence was evaluated revealed the following mutations: Gln679Ter (1 case), Gly723Ter (2 cases), Glu729(1-bp del) (1 case), Leu762(5-bp del) (2 cases), and Asn763(4-bp del) (1 case). All of these mutations cosegregated with RP in the families of the index patients. Nine missense mutations that were each found in six or fewer patients were encountered. The segregation of eight of these was evaluated in the respective patients' families, and only one segregated with dominant RP. This cosegregating missense change was in cis with the nonsense mutation Gln679Ter. Although patients with RP1 mutations had, on average, slightly better visual acuity than patients with rhodopsin mutations, there was no statistically significant difference in final dark-adaptation thresholds, visual field diameters, or cone electroretinogram (ERG) amplitudes. Comparably aged patients with RP1 mutations had visual function that varied by approximately two orders of magnitude, based on visual fields and ERG amplitudes. CONCLUSIONS: Dominant RP1 alleles typically have premature nonsense codons occurring in the last exon of the gene and would be expected to encode mutant proteins that are only approximately one third the size of the wild-type protein, suggesting that a dominant negative effect rather than haploinsufficiency is the mechanism leading to RP caused by RP1 mutations. On average, patients with RP1 mutations have slightly better visual acuity than patients with dominant rhodopsin mutations; otherwise, they have similarly severe disease. The wide range in severity among patients with RP1 mutations indicates that other genetic or environmental factors modulate the effect of the primary mutation.

Mutations in ABCR (ABCA4) in patients with Stargardt macular degeneration or cone-rod degeneration.

PURPOSE: To determine the spectrum of ABCR mutations associated with Stargardt macular degeneration and cone-rod degeneration (CRD). METHODS: One hundred eighteen unrelated patients with recessive Stargardt macular degeneration and eight with recessive CRD were screened for mutations in ABCR (ABCA4) by single-strand conformation polymorphism analysis. Variants were characterized by direct genomic sequencing. Segregation analysis was performed on the families of 20 patients in whom at least two or more likely pathogenic sequence changes were identified. RESULTS: The authors found 77 sequence changes likely to be pathogenic: 21 null mutations (15 novel), 55 missense changes (26 novel), and one deletion of a consensus glycosylation site (also novel). Fifty-two patients with Stargardt macular degeneration (44% of those screened) and five with CRD each had two of these sequence changes or were homozygous for one of them. Segregation analyses in the families of 19 of these patients were informative and revealed that the index cases and all available affected siblings were compound heterozygotes or homozygotes. The authors found one instance of an apparently de novo mutation, Ile824Thr, in a patient. Thirty-seven (31%) of the 118 patients with Stargardt disease and one with CRD had only one likely pathogenic sequence change. Twenty-nine patients with Stargardt disease (25%) and two with CRD had no identified sequence changes. CONCLUSIONS: This report of 42 novel mutations brings the growing number of identified likely pathogenic sequence changes in ABCR to approximately 250.

Null RPGRIP1 alleles in patients with Leber congenital amaurosis.

We isolated and characterized the entire coding sequence of a human gene encoding a protein that interacts with RPGR, a protein that is absent or mutant in many cases of X-linked retinitis pigmentosa. The newly identified gene, called "RPGRIP1" for RPGR-interacting protein (MIM 605446), is located within 14q11, and it encodes a protein predicted to contain 1,259 amino acids. Previously published work showed that both proteins, RPGR and RPGRIP1, are present in the ciliary structure that connects the inner and outer segments of rod and cone photoreceptors. We surveyed 57 unrelated patients who had Leber congenital amaurosis for mutations in RPGRIP1 and found recessive mutations involving both RPGRIP1 alleles in 3 (6%) patients. The mutations all create premature termination codons and are likely to be null alleles. Patients with RPGRIP1 mutations have a degeneration of both rod and cone photoreceptors, and, early in life, they experience a severe loss of central acuity, which leads to nystagmus.

Two families from New England with usher syndrome type IC with distinct haplotypes.

PURPOSE: To search for patients with Usher syndrome type IC among those with Usher syndrome type I who reside in New England. METHODS: Genotype analysis of microsatellite markers closely linked to the USH1C locus was done using the polymerase chain reaction. We compared the haplotype of our patients who were homozygous in the USH1C region with the haplotypes found in previously reported USH1C Acadian families who reside in southwestern Louisiana and from a single family residing in Lebanon. RESULTS: Of 46 unrelated cases of Usher syndrome type I residing in New England, two were homozygous at genetic markers in the USH1C region. Of these, one carried the Acadian USH1C haplotype and had Acadian ancestors (that is, from Nova Scotia) who did not participate in the 1755 migration of Acadians to Louisiana. The second family had a haplotype that proved to be the same as that of a family with USH1C residing in Lebanon. Each of the two families had haplotypes distinct from the other. CONCLUSION: This is the first report that some patients residing in New England have Usher syndrome type IC. Patients with Usher syndrome type IC can have the Acadian haplotype or the Lebanese haplotype compatible with the idea that at least two independently arising pathogenic mutations have occurred in the yet-to-be identified USH1C gene.

Bilateral diffuse uveal melanocytic proliferation associated with extraocular cancers: review of a process particularly associated with gynecologic cancers.

We reviewed cases of a paraneoplastic syndrome in which uveal melanocytes proliferated and led to blindness. Eighteen cases were derived from the literature, and two were taken from our institution. The average patient age at the time of the diagnosis was 63 years (range, 34-89 years). There were 13 women and 7 men. In approximately half of the cases, the ocular symptoms antedated those of the inciting tumor. Most of the inciting tumors were poorly differentiated carcinomas. The most common tumors were from the female genital tract (ovary and uterus) among the women patients and from the lung among the men. Tumors from the breast were rare (one possible case), and tumors of the prostate were conspicuously absent. All five inciting tumors whose histopathology was reviewed expressed neuron-specific enolase, but none prominently expressed antigens more specific for neuroendocrine carcinomas such as chromogranin or synaptophysin. It is our experience that many general pathologists are not aware of this unique paraneoplastic syndrome. Our report is the first to document a statistically significant association between this syndrome and gynecologic cancers.

Survey of patients with granular, lattice, avellino, and Reis-Bücklers corneal dystrophies for mutations in the BIGH3 and gelsolin genes.

OBJECTIVES: To search for novel mutations that cause corneal stromal dystrophies and to confirm or revise the clinical diagnosis of patients with these mutations. PATIENTS: Through review of the records of the Cogan Eye Pathology Laboratory at the Massachusetts Eye and Ear Infirmary, Boston, and of clinical records, we ascertained 14 unrelated patients with the clinical or histopathologic diagnosis of granular (3 cases), Avellino (5 cases), lattice (5 cases), or Reis-Bücklers (1 case) corneal dystrophy. METHODS: Clinical records and histopathologic findings of the index patients and their relatives were reviewed. Patients and selected relatives donated a blood sample from which leukocyte DNA was purified and assayed for mutations in the BIGH3 gene and, in 2 patients, the gelsolin gene, using the polymerase chain reaction and direct genomic sequencing. RESULTS: All index patients with the diagnosis of granular dystrophy or Avellino dystrophy had the missense mutation Arg555Trp or Arg124His, respectively, previously reported in the BIGH3 gene. Of the 5 index patients with a prior diagnosis of lattice dystrophy, 2 had the originally reported lattice mutation (Arg124Cys) in the BIGH3 gene, 1 had a more recently reported missense mutation (His626Arg) in the same gene, 1 had the missense mutation Asp187Asn in the gelsolin gene, and 1 had no detected mutation in either gene. Affected members of the family with Reis-Bücklers dystrophy did not carry the previously reported mutations Arg555Gln or Arg124Leu but instead carried a novel missense mutation Gly623Asp in the BIGH3 gene. CONCLUSIONS: Molecular genetic analysis can improve the accuracy of diagnosis of patients with corneal dystrophies. Two patients with a prior diagnosis of lattice corneal dystrophy had their diagnosis changed to gelsolin-related amyloidosis (1 case) or secondary, nonhereditary localized amyloidosis (1 case). A novel mutation in the BIGH3 gene that causes Reis-Bücklers dystrophy was uncovered through this analysis, and another recently reported novel mutation was encountered. These findings serve to expand our knowledge of the spectrum of pathogenic mutations in BIGH3.

Retinal histopathology of an autopsy eye with advanced retinitis pigmentosa in a family with rhodopsin Glu181Lys.

PURPOSE: To compare histologic findings in an autopsy eye of an 84-year-old man with advanced retinitis pigmentosa and rhodopsin, Glu181Lys, with two cases of autosomal dominant retinitis pigmentosa (one with rhodopsin, Pro23His, and one with rhodopsin, Cys110Arg) and with a normal control, all of comparable age. METHODS: All eyes were prepared for light and electron microscopy within 6 hours after death. RESULTS: Extensive photoreceptor degeneration was revealed in the eyes with retinitis pigmentosa. Some macular cones showed membranous swirls only in the eye with rhodopsin, Glu181Lys. CONCLUSION: The retinal degeneration caused by rhodopsin, Glu181Lys, can feature membranous swirls in the inner segments of cones in the macula. These swirls have not been reported in other cases of dominant retinitis pigmentosa studied so far, and their pathogenesis remains to be defined.

Molecular genetics of Oguchi disease, fundus albipunctatus, and other forms of stationary night blindness: LVII Edward Jackson Memorial Lecture.

PURPOSE: To compare the clinical findings of the various forms of stationary night blindness caused by mutations in identified genes encoding proteins of photoreceptors or the retinal pigment epithelium. METHODS: Review of the visual acuities, visual fields, fundi, dark-adaptation curves, and electroretinograms from patients with stationary night blindness caused by mutations in the genes RHO, GNAT1, PDE6B, RHOK, SAG, RDH5, and CACNA1F, respectively encoding rhodopsin, the alpha subunit of rod transducin, the beta subunit of rod cGMP-phosphodiesterase, rhodopsin kinase, arrestin, 11-cis retinol dehydrogenase, and a retinal L-type calcium channel. RESULTS: In the evaluated forms of stationary night blindness, the time course of dark adaptation and the characteristics of the electroretinogram indicate that rod photoreceptors are present and that they function, although abnormally. In night blindness resulting from defects in rhodopsin, the alpha subunit of rod transducin, or the beta subunit of rod cGMP phosphodiesterase, rod photoreceptors respond only to light intensities far brighter than normal, and the sensitivity of rods to light is similar to that of normal individuals who are not dark adapted. In fundus albipunctatus and in Oguchi disease, the rod photoreceptors can achieve normal sensitivity to dim light but only after 2 or more hours of dark adaptation, compared with approximately 0.5 hours for normal individuals. In each of these forms of stationary night blindness, the poor rod sensitivity and the time course of dark adaptation correlate with the known or presumed physiologic abnormalities caused by the identified gene defects. Patients with some forms of stationary night blindness, such as fundus albipunctatus and Oguchi disease, may develop degeneration of the retina leading to severe loss of vision in later life. CONCLUSIONS: The identification of the mutant genes causing forms of stationary night blindness refines the classification of these diseases and enhances our understanding of the underlying physiologic defects. Ophthalmologists must be aware that although these diseases are traditionally categorized as "stationary," some of them lead to reduced visual acuity or constricted visual fields, especially in older patients. Efforts to develop therapies for these diseases should concentrate on these more severe forms.

Novel rhodopsin mutations Gly114Val and Gln184Pro in dominant retinitis pigmentosa.

PURPOSE: To identify mutations in the rhodopsin gene in North American patients with autosomal dominant retinitis pigmentosa (ADRP) and to measure the proportion of cases with rhodopsin mutations. METHODS: Single-strand conformation polymorphism (SSCP) analysis and direct genomic sequencing were used to evaluate the coding region and intron splice sites of the rhodopsin gene for mutations in 91 unrelated patients. RESULTS: Nineteen patients heterozygously carried a missense change in the rhodopsin gene (six with Pro23His, two with Pro347Leu, and one each with Thr17Met, Phe45Leu, Gly51Arg, Gly89Asp, Gly114Val, Arg135Trp, Pro171Leu, Gln184Pro, Phe220Leu, Ser297Arg, and Pro347Thr). All these missense changes were previously reported as causes for ADRP except for Gly114Val, Gln184Pro, and Phe220Leu, which were evaluated further by examining the relatives of index patients. The Gly114Val and Gln184Pro alleles cosegregated with ADRP as expected if they were pathogenic. Phe220Leu did not, indicating that it is not a cause of ADRP. CONCLUSIONS: Summation of the results of cases in this study with those of 272 unrelated cases of ADRP previously evaluated by our group shows that 90 of 363 (25%) of cases were caused by rhodopsin mutations.

Evaluation of the myosin VIIA gene and visual function in patients with Usher syndrome type I.

Usher syndrome type I (USH1) is a recessively-inherited disorder consisting of retinitis pigmentosa, profound congenital deafness, and vestibular ataxia. It can be caused by mutations in at least six different loci (USH1A-1F). The gene encoding human myosin VIIA (MYO7A) is the USH1B locus. In this study, 66 unrelated patients with USH1 were evaluated for defects in MYO7A using single-strand conformation polymorphism analysis and direct genomic sequencing. Twenty-nine per cent of cases were found to have likely pathogenic MYO7A mutations. A total of 22 likely pathogenic changes were identified, 18 of which were novel. Cosegregation analysis of mutations in five available families showed that the MYO7A changes segregated with the disease in an autosomal recessive fashion. Average visual function as measured by visual acuity, visual field area, and ERG amplitude was not significantly different between the group of patients with likely pathogenic MYO7A changes and the group in which no likely pathogenic MYO7A changes were detected.

X-linked retinitis pigmentosa: mutation spectrum of the RPGR and RP2 genes and correlation with visual function.

PURPOSE: To assess the frequency of RPGR and RP2 mutations in a set of 85 patients with X-linked retinitis pigmentosa (XLRP) and to compare the visual function of patients with mutations in RPGR versus RP2. METHODS: Eighty-five unrelated patients with XLRP were ascertained, mainly from North America. The single-strand conformation polymorphism (SSCP) and a direct sequencing technique were used to screen their DNA for mutations in the coding region and splice sites of RPGR and RP2. The Snellen visual acuities, visual field areas, and 0.5-Hz and 30-Hz electroretinograms (ERGs) were measured in male patients. The visual function parameters were compared using multiple regression analysis. RESULTS: A wide spectrum of mutations was found in both genes, including missense, nonsense, splice-site, and frameshift mutations. Twenty putative pathogenic mutations in RPGR, 15 of which were novel, were found in 22 patients (26%), whereas 6 mutations in RP2, 4 of which were novel, were found in 6 patients (7%). A high fraction of the mutations in both genes affected amino acid residues within or adjacent to presumed functional domains. Comparison of visual function between comparably aged patients with mutations in RPGR versus RP2 showed that, on average, patients with RPGR mutations have lower ERG amplitudes and smaller visual field areas. CONCLUSIONS: Mutations in RPGR and RP2 genes together account for approximately 33% of cases of XLRP in North America. Patients with RPGR mutations have less overall retinal function on average than those with RP2 mutations, on the basis of measurements of visual field areas and full-field ERG amplitudes.

Missense mutation in the USH2A gene: association with recessive retinitis pigmentosa without hearing loss.

Microdeletions Glu767(1-bp del), Thr967(1-bp del), and Leu1446(2-bp del) in the human USH2A gene have been reported to cause Usher syndrome type II, a disorder characterized by retinitis pigmentosa (RP) and mild-to-severe hearing loss. Each of these three frameshift mutations is predicted to lead to an unstable mRNA transcript that, if translated, would result in a truncated protein lacking the carboxy terminus. Here, we report Cys759Phe, a novel missense mutation in this gene that changes an amino-acid residue within the fifth laminin-epidermal growth factor-like domain of the USH2A gene and that is associated with recessive RP without hearing loss. This single mutation was found in 4.5% of 224 patients with recessive RP, suggesting that USH2A could cause more cases of nonsyndromic recessive RP than does any other gene identified to date.

Intraocular-central nervous system lymphoma: clinical features, diagnosis, and outcomes.

OBJECTIVE: To analyze the clinical features, laboratory investigations, and diagnosis of intraocular-central nervous system (CNS) lymphoma in a cohort of patients who underwent diagnostic vitrectomy. DESIGN: Retrospective case series. METHOD AND STUDY MATERIALS: Thirty-four vitreous biopsy specimens obtained from 26 patients with treatment-resistant or unusual uveitis were re-evaluated in a masked fashion. The specimens were classified into three groups: "negative," "suspicious of malignancy," and "positive" based on the cytologic features, immunomarkers, and flow cytometry. The medical records of the patients were reviewed retrospectively. MAIN OUTCOME MEASURES: The reliability of vitreous cytology in diagnosing intraocular-CNS lymphoma and the differences in clinical features of patients with intraocular-CNS lymphoma and uveitis. RESULTS: The two ocular pathologists concurred in their criteria for interpretation of all specimens. There was 100% concordance between the cytologic reports read independently by the two ocular pathologists over the 5-year period and the read-out done in a masked fashion at the time of the study. Ten patients were diagnosed with intraocular-CNS lymphoma based on the vitreous cytology and clinical features. The time interval between the initial presentation and vitreous biopsy was 1 week to 2 years, with 80% of the patients diagnosed within the first year. Retinal involvement in the form of lymphomatous subretinal pigment epithelial infiltrates, vasculitis, and apparent retinochoroiditis was present in six cases. Initial neuroimaging studies revealed concomitant CNS involvement in three patients, and an additional three developed CNS lymphoma following diagnosis by vitreous biopsy. Patients were treated with radiotherapy, chemotherapy, or both. Two of the four patients with a follow-up of greater than 12 months died due to CNS involvement. CONCLUSIONS: Vitreous cytology is a sensitive, reliable, and reproducible method of diagnosing intraocular-CNS lymphoma. A high index of suspicion based on the clinical findings and course of the uveitis is critically important in decision-making for diagnostic vitrectomy. Central nervous system involvement is frequent and associated with a high mortality rate. Ophthalmology 1999;106:1805-1810