The removal of 10/0 polyester (Mersilene) sutures after small incision congenital cataract surgery.

PURPOSE: To evaluate the use of 10/0 polyester (Mersilene) sutures for closure of small corneal incision after congenital cataract surgery. METHODS: The authors retrospectively reviewed the medical records of 58 cases (42 patients) who underwent congenital cataract extraction and intraocular lens implantation between 1999 and 2004, using Mersilene sutures. An examination looking for suture-related complications and retinoscopy was done 1 week after surgery and then every month for 6 months. The sutures were removed in cases of local tissue reaction, but not due to high postoperative astigmatism. Paired t-test was used to compare patients' age and astigmatism level in those cases who had suture removal (Group 1) as opposed to those who did not (Group 2). RESULTS: In 10 cases (17%) corneal vascularization, necessitating suture removal, was found during 6-month follow-up period, without the trigger of loose suture. Patient age was 3.5+/-3.3 years and 4.4+/3.3 years in Groups 1 and 2, respectively. At 1 week postoperatively the astigmatism value was 1.7+/-1.7 diopter (D) and 2.3+/-2.2 D in Groups 1 and 2, respectively, and it reduced to 0.9+/-0.8 in both groups at 6 months postoperatively. One case of endophthalmitis was encountered 2 days after suture removal. CONCLUSIONS: Removal of Mersilene sutures after congenital cataract surgery is required in cases of corneal vascularization, occurring during the first months postoperatively. Owing to the risk of general anesthesia and infection, suture removal should be considered with caution in cases of postoperative astigmatism.

Astigmatism outcomes of scleral tunnel and clear corneal incisions for congenital cataract surgery.

PURPOSE: To evaluate astigmatism outcomes after congenital cataract surgery with intraocular lens implantation using clear corneal or scleral tunnel incisions. METHODS: We retrospectively reviewed the medical records of 46 children (67 eyes), aged 2 months to 12 years, who had undergone nontraumatic cataract extraction and intraocular lens implantation between 1996 and 2001, using a scleral tunnel incision (group 1), or a clear corneal incision (group 2). Refractive astigmatism was measured at 1 week, 3 months, and 5 months after surgery. Paired t-test was used to compare those variables, and Spearman's correlation was used to determine their relation to patient's age. RESULTS: Mean+/-SD astigmatism at 1 week postoperatively was 3.1+/-2.8 Diopter (D) and 2.1+/-1.7 D in groups 1 and 2, respectively. It significantly reduced to 1.1+/-1.2 D and 0.9+/-1.0 D, respectively, in the two groups at 5 months postoperatively (P<0.007). In both groups patients' age was significantly correlated with 1-week postoperative astigmatism (group 1: r=0.64; P=0.001; group 2: r=-0.58; P=0.003), and with the change in cylinder magnitude between 1 week and 3 months postoperatively (group 1: r=-0.67; P=0.001; group 2: r=0.50; P=0.013). CONCLUSION: Children who underwent congenital cataract surgery using clear corneal or scleral tunnel incisions showed high postoperative astigmatism at 1 week postoperatively, which spontaneously reduced during 5 months follow-up. Therefore, suture removal is not necessary in those cases.

An increase in superoxide dismutase ameliorates oxygen-induced retinopathy in transgenic mice.

PURPOSE: Oxygen therapy is a well-recognized risk factor for retinopathy of prematurity. We examined whether an increase in the naturally occurring enzyme copper-zinc superoxide dismutase (CuZnSOD), which controls oxygen, can reduce the severity of oxygen-induced retinopathy in a mouse model. METHODS: Seven transgenic mice overexpressing CuZnSOD and six wild-type mice were exposed to 75% oxygen from postnatal day 7 to 12. Seven transgenic mice and five mice of the wild type were kept in room air and served as controls. Fluorescein-conjugated dextran angiography of retinal vasculature was performed and flat-mounted preparations were evaluated by scoring blood vessel growth, blood vessel tuft formation, extraretinal neovascularization, degree of central constriction, and tortuosity of vessels. In addition, quantification of the number of blood vessel tufts was performed in a masked fashion with haematoxylin and eosin staining of paraffin-embedded eye sections. RESULTS: The mean retinal score+/-SD obtained by the wild-type mice was 9.4+/-2.0, whereas the transgenic mice overexpressing CuZnSOD obtained a value of 2.4+/-1.6 (P=0). The two control groups (wild type and transgenic) that were kept in room air, each obtained a score of 0. Significantly fewer extraretinal vascular tufts were seen in the transgenic mice (0.26+/-0.34) than in the wild-type mice (4.27+/-1.6) after both groups were exposed to oxygen (P<0.001). CONCLUSIONS: The results suggest that high SOD activity protects neonatal mice against oxygen-induced retinopathy, and support the assumption that oxygen radicals are a major causative factor in oxygen-induced retinopathy.

Evaluation of superior rectus muscle attachment following hang-back recession in rabbit eyes.

PURPOSE: The hang-back suture technique has been advocated to decrease the risk of scleral perforation during strabismus surgery. In this study, we evaluated the muscle insertion site in rabbits 4 weeks after a hang-back recession was performed. METHODS: Twenty-five eyes of 13 rabbits underwent hang-back recessions of between 5 and 8 mm of the superior rectus muscle. Four weeks later, the attachment sites were examined. RESULTS: Four weeks following the surgery, 14 muscles (n=25, 56%) were anteriorly displaced. In the 5 mm recession group, one muscle was anteriorly displaced (n=7, 14.3%). In the 6 mm recession group, 50% of the muscles recessed were displaced anteriorly (n=8). The 7 mm hang-back recession group demonstrated forward displacement in five muscles operated (n=6, 83%) and in the 8 mm recession group, all four muscles (100%) were anteriorly displaced. The magnitude of displacement was positively correlated to the amount of the hang-back recession performed (Pearson correlation p<0.001). CONCLUSIONS: Anterior displacement of muscles using the hang-back technique in the rabbit eye is unacceptably high and occurred in 56% of the cases. A positive, statistically significant correlation exists between the amount of recession performed and the number of muscles displaced from their new insertion. Therefore, when performing large recessions using the hang-back technique displacement should be anticipated.

Changes in astigmatism after congenital cataract surgery and intraocular lens implantation using scleral tunnel incision.

PURPOSE: To evaluate the post-operative changes in astigmatism in pseudophakic eyes in children. Only eyes with astigmatism of 3.0 D or more were included in the study. METHODS: The charts of children who had undergone surgery for non-traumatic cataract, using a scleral tunnel method were retrospectively reviewed. In 11 eyes with astigmatism of 3.0 D or more, the refraction was tested and recorded at 1 week, 3 months and 5 months post-operatively. The paired t-test was used to compare between the variables. RESULTS: Mean astigmatism 1 week post-operatively was 5.8 +/- 3.6 D (range 3.0-14.0 D). Thereafter, the astigmatic component of the refractive error underwent a spontaneous steady decline, reaching a mean value of 2.1 +/- 1.3 D (range 1-4.0 D) 5 months after surgery. The change in the difference between the mean values at 1 week and at 5 months was statistically significant (P < 0.005). CONCLUSION: Children who underwent congenital cataract surgery and intraocular lens implantation showed a significant spontaneous reduction in astigmatism post-operatively.

Ectopic HP1 promotes chromosome loops and variegated silencing in Drosophila.

A transgene inserted in euchromatin exhibits mosaic expression when targeted by a fusion protein made of the DNA-binding domain of GAL4 and the heterochromatin-associated protein HP1. The silencing responds to the loss of a dose of the dominant modifiers of position-effect variegation Su(var)3-7 and Su(var)2-5, the locus encoding HP1. The genomic environs of the insertion site at 87C1 comprise the dispersed repetitive elements micropia and alphagamma. In the presence of the GAL4-HP1 chimera, the polytene chromosomes of this line form loops between the insertion site of the transgene and six other sections of chromosome 3R, as well as, rarely, with pericentric and telomeric heterochromatin. In contrast to the insertion site of the transgene at 87C, the six loop-forming sites in the euchromatic arm were each previously described as intercalary heterochromatin. Moreover, GAL4-HP1 tethering on one homologue trans-inactivates the reporter on the other. HP1, probably together with other partners, could thus facilitate the coalescence of dispersed middle repetitive sequences, and organize the heterochromatic structure responsible for the variegated silencing of nearby euchromatic genes.

The iab-7 polycomb response element maps to a nucleosome-free region of chromatin and requires both GAGA and pleiohomeotic for silencing activity.

In the work reported here we have undertaken a functional dissection of a Polycomb response element (PRE) from the iab-7 cis-regulatory domain of the Drosophila melanogaster bithorax complex (BX-C). Previous studies mapped the iab-7 PRE to an 860-bp fragment located just distal to the Fab-7 boundary. Located within this fragment is an approximately 230-bp chromatin-specific nuclease-hypersensitive region called HS3. We have shown that HS3 is capable of functioning as a Polycomb-dependent silencer in vivo, inducing pairing-dependent silencing of a mini-white reporter. The HS3 sequence contains consensus binding sites for the GAGA factor, a protein implicated in the formation of nucleosome-free regions of chromatin, and Pleiohomeotic (Pho), a Polycomb group protein that is related to the mammalian transcription factor YY1. We show that GAGA and Pho interact with these sequences in vitro and that the consensus binding sites for the two proteins are critical for the silencing activity of the iab-7 PRE in vivo.

The bithorax complex of Drosophila melanogaster: Underreplication and morphology in polytene chromosomes.

The level of polyteny of the Drosophila salivary gland chromosomes was determined throughout the chromosome region 89E1-4, the locus of the Bithorax Complex. A zone of underreplication spans the 300 kb of DNA from the Ubx to Abd-B loci. From the centromere proximal end of the complex, a 70-kb-long gradual decrease of polytenization starts with the Ubx transcription unit and, after a floor corresponding to the abd-A locus, raises gradually back to the maximum over 70 kb in the region of the Abd-B transcription unit. In flies carrying the mutation Suppressor of DNA Underreplication [Su(UR)ES], the underreplication of the Bithorax Complex is fully suppressed. In the wild type, the Bithorax Complex forms a weak point featuring thinner bands separated by clefts or constrictions. In Su(UR)ES strain in contrast, the 89E1-4 band looks like a single solid band consisting of homogenous dense material. We speculate that the wild-type Su(UR)ES protein hampers DNA replication of silenced domains and leads to their underreplication in salivary gland polytene chromosomes.

The genomic silencing of position-effect variegation in Drosophila melanogaster: interaction between the heterochromatin-associated proteins Su(var)3-7 and HP1.

Position-effect variegation results from mosaic silencing by chromosomal rearrangements juxtaposing euchromatin genes next to pericentric heterochromatin. An increase in the amounts of the heterochromatin-associated Su(var)3-7 and HP1 proteins augments silencing. Using the yeast two-hybrid protein interaction trap system, we have isolated HP1 using Su(var)3-7 as a bait. We have then delimited three binding sites on Su(var)3-7 for HP1. On HP1, the C-terminal moiety, including the chromo shadow domain, is required for interaction. In vivo, both proteins co-localise not only in heterochromatin, but also in a limited set of sites in euchromatin and at telomeres. When delocalised to the sites bound by the protein Polycomb in euchromatin, HP1 recruits Su(var)3-7. Finally, and in contrast with euchromatin genes, a decrease in the amounts of both proteins enhances variegation of the light gene, one of the few genetic loci mapped within pericentric heterochromatin. This body of data supports a direct link between Su(var)3-7 and HP1 in the genomic silencing of position-effect variegation.

Adjustment of sutures 8 hours vs 24 hours after strabismus surgery.

PURPOSE: To compare the postoperative results of adjustable-suture strabismus surgery when suture adjustment was performed 8 hours (group 1) and 24 hours (group 2) after surgery. METHODS: A retrospective clinical study was conducted in two hospitals. Strabismus surgery and muscle adjustment were performed in 90 patients. All patients had horizontal strabismus (40 patients had esotropia and 50 patients had exotropia), and they underwent either primary surgery or reoperation. Mean age of the patients was 29.9 +/- 14.1 (range, 14 to 74) years. The angle of deviation was measured in all patients before surgery, after surgery both before and after adjustment, and at the final follow-up examination. The follow-up period was 6 to 40 months (mean, 19.6 months). RESULTS: Preoperative data were similar in the two groups. The mean angle of deviation immediately after muscle adjustment was 0.6 +/- 6. 1 prism diopters in group 1 and 0.4 +/- 6.3 prism diopters in group 2. This similar deviation in the two groups (P =.9) changed during the follow-up period, and at the final examination the measured angles in groups 1 and 2 were -1.0 +/- 7.9 and -2.5 +/- 10.3 prism diopters, respectively (P =.48). The most considerable outcome measure was the calculated drift values. At the last follow-up these values were -1.6 +/- 5.8 for group 1 and -2.9 +/- 11 prism diopters for group 2 (P =.5). Subdividing the patients on the basis of their deviation before surgery, a postoperative drift toward exotropia was found in most patients of group 1. In group 2, however, a greater tendency toward exotropia was shown only by those patients who had displayed exotropia preoperatively, whereas patients with preoperative esotropia showed a greater tendency toward esotropia after surgery. CONCLUSION: In patients undergoing horizontal extraocular muscle surgery with adjustable sutures, suture adjustment 8 hours or 24 hours after surgery did not produce significantly different results.

Strabismus surgery in children with Möbius syndrome.

Möbius syndrome is a congenital disorder of facial diplegia associated with lateral gaze paralysis. Although palsy of the sixth and seventh cranial nerves is the minimum diagnostic finding for Möbius syndrome, neuropathologic evidence indicates that this is a more complex syndrome.(1) Clinically, it is characterized by a total absence of facial expression and severe esotropia. Other anomalies may be associated with this syndrome, especially other cranial nerve palsies and Poland syndrome. The etiology of this syndrome has not been clearly established. Brain stem necrosis resulting from a vascular deficiency has been offered as a possible pathogenetic explanation.(2) The strabismus in Möbius syndrome is congenital esotropia with bilateral limitation in abduction. Even though many reports have described the various features of Möbius syndrome, only a few articles have reported the results of strabismus surgery in children, including bimedial rectus muscle recession. (3-5) Some authors report that bilateral medial rectus muscle recession alone has been disappointing; therefore, a combination of a medial rectus muscle recession and a lateral rectus muscle resection was recommended for satisfactory results. (5-7) In more severe cases, muscle transposition was needed to ensure straight position of the eyes in primary gaze. (8-9)

OVO transcription factors function antagonistically in the Drosophila female germline.

OVO controls germline and epidermis differentiation in flies and mice. In the Drosophila germline, alternative OVO-B and OVO-A isoforms have a common DNA-binding domain, but different N-termini. We show that these isoforms are transcription factors with opposite regulatory activities. Using yeast one-hybrid assays, we identified a strong activation domain within a common region and a counteracting repression domain within the OVO-A-specific region. In flies, OVO-B positively regulated the ovarian tumor promoter, while OVO-A was a negative regulator of the ovarian tumor and ovo promoters. OVO-B isoforms supplied ovo(+) function in the female germline and epidermis, while OVO-A isoforms had dominant-negative activity in both tissues. Moreover, elevated expression of OVO-A resulted in maternal-effect lethality while the absence of OVO-A resulted in maternal-effect sterility. Our data indicate that tight regulation of antagonistic OVO-B and OVO-A isoforms is critical for germline formation and differentiation.

A GAL4-HP1 fusion protein targeted near heterochromatin promotes gene silencing.

We have constructed a new reporter transgene, Winkelried, equipped with a synthetic binding site for the yeast GAL4 transcriptional activator. The binding site is inserted between the white and lacZ reporter genes, and is flanked by FRT sequences. These elements allow excision of the GAL4 binding site by crossing the transgenic line with an FLP recombinase producing strain. We have generated by X-ray irradiation two independent chromosomal rearrangements, Heidi and Tell, relocating Winkelried next to pericentromeric heterochromatin. These rearrangements induce variegation of both white and lacZ. Variegation of Winkelried in the rearranged transgenic lines responds to the loss and excess of doses of the dominant suppressors of position-effect variegation (PEV) Su(var)3-7 and Su(var)2-5. Winkelried therefore constitutes a unique tool to test the effect on variegation in cis of any factor fused to the GAL4 DNA binding domain. Indeed, a chimeric protein, made of the DNA binding site of GAL4 and of HP1, the modifier of PEV encoded by Su(var)2-5, is shown to enhance variegation of Heidi and Tell. Excision of the binding sites for GAL4 in the variegating rearrangements Heidi and Tell abolishes the modifier effect of the GAL4-HP1 chimera. Therefore, in the Heidi and Tell rearrangements, enhancement of position-effect variegation depends strictly both on the concentration of GAL4-HP1 and on the presence of its binding site in the vicinity of the reporter genes.

Strabismus surgery using the adjustable suture technique.

BACKGROUND AND OBJECTIVE: To determine the results of adjustable suture technique used in horizontal muscle surgery. MATERIALS AND METHODS: Seventy-eight charts of patients who underwent strabismus surgery between the years 1993 and 1995 were examined retrospectively. The study included 35 cases of esotropia (ET), and 43 cases of exotropia (XT). The results of strabismus surgery were measured and compared 1 day after adjustment; the final results between 6 and 24 months after the surgical procedure. RESULTS: Adjustment was required in 39% of all patients. The highest rate of adjustment was required in patients who underwent monocular surgery for XT (51%), and the lowest rate of adjustment was undertaken in patients who underwent monocular surgery for ET (16%). Mean changes in the angle of deviation between 1 day after surgery to the last follow up was 2.2 prism diopters (delta) (+/-11.2 delta) for cases of esotropia, and 4.6 delta (+/-8.7 delta) for exotropia. The most significant drift was found in patients with XT who underwent binocular surgery 6.8 delta (+/-0.9 delta) and the smallest drift was found in patients with ET who underwent binocular surgery 5.2 delta (+/-5.6 delta). CONCLUSION: Esotropic and exotropic patients have a tendency to drift towards their original deviation postoperatively. It is possible, therefore, that mild overcorrection in the early postoperative period will result in better long-term results.

Vision screening of preverbal children with Teller acuity cards.

OBJECTIVE: To evaluate the modified Teller visual acuity test as a mass screening tool for testing visual acuity in infants and preverbal children. DESIGN: Prospective case series. PARTICIPANTS: A total of 1126 healthy children undergoing mandatory examination at the Mother and Child Health Center. INTERVENTION: Visual acuity was tested by the modified Teller visual acuity test. MAIN OUTCOME MEASURES: Visual acuity was measured in all children. Clinical evaluation was performed in children who failed the Teller acuity test and in a control group. RESULTS: Visual acuity was below the normal range in 5% of the children. In the study group referred for complete eye examination, there were 9% false-negative and 44% false-positive results. In the age range of 12 to 17 months, false-negative and false-positive results were obtained in 5.6% and 50% of the children, respectively. CONCLUSIONS: The Teller acuity card procedure can be used for vision screening in preverbal children. Testing was associated with a high rate of false-positive results.

Refractive status in children after long-term follow up of cataract surgery with intraocular lens implantation.

PURPOSE: To evaluate the resultant refractive status in children 5 to 11 years after cataract surgery with a high power intraocular lens (IOL) implantation. METHODS: Charts of eight patients (10 eyes) who underwent cataract surgery with IOL implantation by the same technique were reviewed. Age at surgery was 2 months to 3 years. High-power IOL of 27.0 to 30.0 diopters (D) was implanted in seven eyes and lower IOL (between 19.0 D to 23.0 D) in three eyes. Follow-up period was between 5 and 11 years. RESULTS: In children who received a high-power IOL, the resultant refraction after 5 to 7 years was found to be between -5.50 and -12.00 D. In the group that had a lower power IOL implanted, the refraction was between -2.50 and +9.00 after 6 to 11 years. The results were plotted on a graph of refraction vs. IOL power and showed that the IOL power that may result in emmetropia in an older child is 23.2D. CONCLUSIONS: The implantation of a high-power IOL (27 D to 30 D) in eight young children resulted in refractive status within 3 D of emmetropia during the first year or two of life and in high myopia at age 5 to 12 years.

Superior oblique muscle paresis after sub-Tenon's anesthesia for cataract surgery.

A 68-year-old man developed strabismus after having sub-Tenon's anesthesia for cataract extraction and intraocular lens implantation. An ipsilateral hypertropia with superior oblique muscle paresis developed in the operated eye. The hypertropia appeared 1 day after surgery and resolved 1 month later. Although sub-Tenon's anesthesia is considered safer than other methods of local anesthesia, strabismus may occur.

Changes in astigmatism after cataract extraction and intraocular lens implantation in children.

PURPOSE: To evaluate the post-operative changes in astigmatism in pseudophakic eyes in children. METHODS: The charts of children who had undergone surgery for non-traumatic cataract were retrospectively reviewed. In 10 eyes with astigmatism of 3.0 D or more, the refraction was tested and recorded at 1 week, 3 months and 5 months post-operatively. RESULTS: Mean astigmatism 1 week post-operatively was 6.2 +/- 2.7 D (range 3.0-11.0 D). Thereafter, the astigmatic component of the refractive error underwent a spontaneous steady decline, reaching a mean value of 1.2 +/- 1.1 D (range 0-3.0 D) 5 months after surgery. The change in the difference between the mean values at 1 week and at 5 months was statistically significant (p = 0.0002). CONCLUSIONS: Children who underwent cataract extraction and intraocular lens implantation showed a significant spontaneous reduction in astigmatism post-operatively. This finding suggests that there is no need to remove sutures in order to achieve reduction of post-operative astigmatism in these children.

Transient extraocular muscle palsy resulting from inferior alveolar nerve block in children.

Transient extraocular muscle palsy after inferior alveolar nerve block was described in adults. Two children who had dental treatment under inferior alveolar nerve block developed this complication. One child suffered from lateral rectus muscle palsy, and the other child from levator palpebral muscle palsy. Both cases recovered spontaneously after a short time.