Impact of changing oxygenation policies on retinopathy of prematurity in a neonatal unit in Argentina.

AIMS: To assess the impact of different oxygenation policies on the rate and severity of retinopathy of prematurity (ROP). METHODS: Between January 2003 and December 2006, infants of 1500 g birthweight (BW) or less and/or 32 weeks gestational age (GA) or less, and larger, more mature infants with risk factors for ROP were examined through three different time periods: period 1: high target oxygen saturation levels (88-96%) and treatment at threshold ROP; period 2: low target oxygen saturation levels (83-93%) and treatment at threshold ROP; period 3: low target oxygen saturation and treatment at type 1 ROP. RESULTS: Type 1 ROP was detected more frequently in babies of 32 weeks GA or less (50/365, 13.7%) than in more mature babies (15/1167, 1.3%; p<0.001). The rate of type 1 ROP in period 1 was 6.9%; period 2, 3.6% and period 3, 1.8%. Rates of stage 3 ROP declined over time in both BW/GA groups (from 9.0% to 4.1% to 2.0%) as did rates of plus disease (from 7.5% to 3.6% to 1.8%). Mean BW and GA declined from period 1 to period 3, and death rates remained unchanged. 74.4% of babies received all the examinations required; 48.1% of treatments were undertaken after discharge from the neonatal unit. CONCLUSIONS: Lower target oxygen saturation was associated with a lower rate of severe ROP without increasing mortality, and changed the characteristics of affected babies. Screening criteria need to remain wide enough to identify all babies at risk of ROP needing treatment.

The cornea of Guinea pig: structural and functional studies.

OBJECTIVE: To describe the functional and structural characteristics of the cornea in healthy Guinea pigs. ANIMALS STUDIED: Healthy male and female pigmented and albino Guinea pigs (Caviaporcellus) aged 3-5 months old were used. PROCEDURES: The animals' corneas underwent different in vivo studies including: slit-lamp biomicroscopy, fluorescein staining (FS), break-up time test (BUT), confocal microscopy and pachymetry. The corneas were also studied histopathologically with light microscopy, immunohistochemistry and transmission electron microscopy. RESULTS: No significant differences were found between pigmented and albino animals, male and female, OD and OS in any study performed. The differences on corneal thickness values were not significant among central (227.85 +/- 14.09 microm) and upper and temporal peripheral regions (226.60 +/- 12.50 and 225.70 +/- 14.40 microm, respectively). All histological studies performed permitted identification and precise description of the different corneal structures in Guinea pigs: the stratified epithelium (45.52 +/- 5.26 microm), Bowman's layer (2.23 +/- 0.38 microm), stroma (163.69 +/- 4.90 microm), Descemet's membrane (3.96 +/- 0.46 microm) and the endothelium (5.09 +/- 0.71 microm). Combining results from all eyes mean and SD from corneal BUT values was 4.98 +/- 1.67 s. Corneas often showed discrete superficial erosions being the FS positive in both eyes from all the animals. CONCLUSION: This study provides a detailed in vivo and postfixed histological description of the Guinea pig's cornea and information about the physiological tests.

Parálisis unilateral de la elevación / Unilateral elevation palsy

Objetivos: analizar la incidencia y características clínicas de pacientes con parálisis unilateral de la elevación (PUE) en nuestra consulta privada. Pacientes y métodos: evaluamos las historias clínicas de 822 pacientes estrábicos estudiados consecutivamente. Estudiamos la presencia de estrabismo horizontal asociado, de inversión anómala, del fenómeno de Bell, tortícolis y ptosis o pseudoptosis. Estudiamos clínicamente los movimientos sacádicos en el plano vertical. Cuatro pacientes con doble parálisis de los elevadores (DPE) fueron operados mediante la técnica de Knapp modificada. Resultados: 7 pacientes presentaron una PUE. Seis casos correspondían a una DPE presentando hipotropia en el ojo afectado, pseudoptosis y ptosis y fénomeno de Bell negativo ipsilateral. El caso restante correspondía a una parálisis unilateral de la elevación de origen supranuclear presentando ortotropia en PPM y fenómeno de Bell positivo en el ojo afectado. Entre los casos de DPE dos estaban asociados al fenómeno de Marcus Gunn (FMG). Clínicamente no pudimos establecer diferencias en la velocidad sucádica entre ambos ejes en los 7 pacientes estudiados. Los cuatro pacientes con DPE operados mostraron ducciones pasivas normales y obtuvieron un buen alineamiento ocular en PPM. Conclusión: Las PUE son cuadros clínicos infrecuentes. La asociación de PUE y FMG confirmaría el diagnóstico de DPE.

Purpose: to analyze the incidence and clinical characteristics of patients with unilateral elevation palsy (UEP) in our private practice. Patients and methods: 822 clinical recordd of strabismus patients seen consecutively were evaluated. We studied the existence of horizontal strabismus, anomalous innervations, Bell's phenomenon, torticollis and ptosis or pseudoptosis. We studied vertical saccadic movements. Four patients with double elevator palsy (DEP) were operated with a Knapp modified procedure. Results: 7 patients had UEP. Six had double elevator paresis (DEP) presenting hypotropia of the involved eye, pseudoptosis, ptosis and ipsilateral negative Bell's phenomenon. The other case was a supranuclear elevation palsy with ortotropia in primary position and, positive Bell's phenomenon in the affected eye. Two DEP patients were associated with Marcus Gunn phenomenon (MGF). Clinically we couldn't find differences in saccadic velocity between both eyes of 7 patients. The four patients with DEP that were operated had normal passive ductions and attained good results. Conclusions: clinical causes of UEP are infrequent. The association of UEP and MGF would support DEP diagnosis.