Search

Pregnancy may be associated with ocular changes, which most often are transient in nature. It can exacerbate preexisting conditions or be associated with development of new conditions. The ocular effects of pregnancy may be divided into physiologic changes, pathologic conditions, or modifications of preexisting conditions. Pathologic conditions include entities such as preeclampsia and eclampsia, along with conditions that are seen with increased frequency during pregnancy such as central serous chorioretinopathy. The most significant modified preexisting condition is diabetes mellitus. The various effects of pregnancy on the eye will be reviewed throughout this chapter.

Fragile X [fra (X)] syndrome is a frequently encountered form of mental retardation and is inherited as an X-linked semi-dominant trait with reduced penetrance. We report here the characterization of a highly polymorphic dinucleotide repeat, DXS 548, which is approximately 150 kb proximal to the fra(X) site and the associated FMR-1 gene. DXS 548 is tightly linked to the fra (X) syndrome locus (FRAXA) without recombination (LOD = 9.07 with q of 0) in selected families with crossovers between FRAXA and very closely linked flanking markers. This dinucleotide repeat could be useful in determining the parental origin of a new fra (X) mutations and evaluating the role of FMR-1 in X-linked non-specific mental retardation.

Objective To the report 20-year follow-up data for patients receiving a scleral buckle for treatment of a primary rhegmatogenous retinal detachment (RRD). Methods Nonconsecutive, retrospective case series. We identified 227 eyes with primary RRD who were treated with a scleral buckle, and for whom at least 20 years of follow-up data were available. Results were classified into 3 subgroups: retina reattached with 1 procedure; retina reattached with 1 or more additional vitreoretinal procedures; or retina detached at 20 years. Results One hundred eighty-six eyes (82%) achieved retinal reattachment with 1 scleral buckling procedure and with a median final visual acuity of 20/40 at 20 years of follow-up. An additional 30 eyes (13%) achieved retinal reattachment after 1 or more additional vitreoretinal procedures, with a median final visual acuity of 20/50. Eleven eyes (5%) were detached at the 20-year follow-up examination, with a final visual acuity in all eyes of no light perception. Conclusions Scleral buckling for primary RRD achieves anatomical efficacy and preservation of central vision in the majority of eyes at 20 years' follow-up. The 1-operation success rate was 82%, overall success rate was 95%, and median final visual acuity was 20/40. This study may serve as a basis for comparison with the long-term results of other surgical techniques used in the treatment of primary RRDs.

The recent cloning of several disease genes has identified the instability of trinucleotide repeats as a fundamental mechanism for variation within the human genome. This mutation mechanism explains the unique inheritance characteristics of the diseases it causes, and there is a significant potential that this mechanism is involved in the pathogenesis of other, as yet uncharacterized, genetic diseases.

Fragile X syndrome results from mutations in a (CGG)n repeat found in the coding sequence of the FMR-1 gene. Analysis of length variation in this region in normal individuals shows a range of allele sizes varying from a low of 6 to a high of 54 repeats. Premutations showing no phenotypic effect in fragile X families range in size from 52 to over 200 repeats. All alleles with greater than 52 repeats, including those identified in a normal family, are meiotically unstable with a mutation frequency of one, while 75 meioses of alleles of 46 repeats and below have shown no mutation. Premutation alleles are also mitotically unstable as mosaicism is observed. The risk of expansion during oogenesis to the full mutation associated with mental retardation increases with the number of repeats, and this variation in risk accounts for the Sherman paradox.

Fragile X syndrome is the most frequent form of inherited mental retardation and is associated with a fragile site at Xq27.3. We identified human YAC clones that span fragile X site-induced translocation breakpoints coincident with the fragile X site. A gene (FMR-1) was identified within a four cosmid contig of YAC DNA that expresses a 4.8 kb message in human brain. Within a 7.4 kb EcoRI genomic fragment, containing FMR-1 exonic sequences distal to a CpG island previously shown to be hypermethylated in fragile X patients, is a fragile X site-induced breakpoint cluster region that exhibits length variation in fragile X chromosomes. This fragment contains a lengthy CGG repeat that is 250 bp distal of the CpG island and maps within a FMR-1 exon. Localization of the brain-expressed FMR-1 gene to this EcoRI fragment suggests the involvement of this gene in the phenotypic expression of the fragile X syndrome.

Objective To report the incidence of acute postinjection endophthalmitis following intravitreal injection of triamcinolone acetonide (IVTA) as an office procedure. Methods Retrospective, noncomparative, consecutive, interventional case series of all patients who had received IVTA at 2 clinical centers between January 1, 2000, and January 30, 2004. Results A total of 1006 eyes received IVTA. None of the eyes developed acute, culture-positive, postoperative endophthalmitis in the 6 weeks following the procedure. One patient developed acute, culture-negative, postoperative endophthalmitis 4 days after receiving IVTA, resulting in an incidence of 0.10%. In this case, the presenting symptoms were decreased vision and acute conjunctival erythema. The case was notable for the absence of pain or hypopyon. Conclusion Although acute postoperative endophthalmitis may follow IVTA, our experience suggests that this is a relatively uncommon event.