Effects of congenital ptosis on the refractive development of eye and vision in children.

AIM: To investigate the influence of unilateral congenital ptosis on the development of the eye and vision in children. METHODS: In this prospective observational study, 41 patients with unilateral congenital ptosis were enrolled (age range 3-15y). The blepharoptosis was divided into 3 subgroups according to the margin reflex distance-1 (MRD-1), including mild group (MRD-1≥2 mm), moderate group (0≤MRD-1<2 mm), and severe group (MRD-1<0 mm). The fellow eyes served as controls. All subjects underwent ocular examinations, including axial length, keratometry, and refractive error. RESULTS: The incidence of astigmatism (ptotic eyes: 58.5% vs fellow eyes: 24.4%, P=0.002) and magnitude of cylindrical power (ptotic eyes: -0.86±0.79 D vs fellow eyes: -0.43±0.63 D, P=0.003) differed significantly between the ptotic eyes and the fellow eyes. The spherical equivalent refraction (P=0.006), spherical power (P=0.01), cylindrical power (P=0.011), axial length-corneal radius (AL/CR) ratio (P=0.009), frequency of hyperopia (P=0.002) and astigmatism (P=0.004) were significantly different among the ptotic eye subgroups and the fellow eye group. In addition, in patients with congenital ptosis, the incidence of amblyopia is 43.9% and the incidence of anisometropia is 24.4%. More importantly, the ratio of AL/CR showed significantly positive correlation with the severity of ptosis (P=0.002). CONCLUSION: Congenital ptosis may lead to a delayed eyeball development in the aspect of AL/CR. The risk of amblyopia is also increased due to visual deprivation and aggravated anisometropia, particularly in severe ptosis case.

Time-dependent inflammatory factor production and NFκB activation in a rodent model of intermittent hypoxia.

OBJECTIVE: To study the systemic production of inflammatory factors and activation of transcription factor nuclear factor kappa B (NF-κB) in response to different levels of intermittent hypoxia and time. METHODS: A total of 160 male Wistar rats were divided randomly into five groups. The first three groups were exposed to 5%, 7.5% and 10% intermittent hypoxia (referred to as IH-1, IH-2, and IH-3 respectively), the fourth group were subjected to 10% sustained hypoxia (abbreviated as SH), and the control group were exposed to normal oxygen (designated SC). At the second, fourth, sixth, and eighth week, eight rats in each group were sacrificed to collect serum. Enzyme-linked immunosorbent assay (ELISA) was used to detect the serum concentration of tumour necrosis factor alpha (TNF-α), interleukin-8 (IL-8), interleukin-6 (IL-6) and interleukin-10 (IL-10). Western blot was used to detect the protein levels of the phosphorylated NF-κB P65 in the nucleus of arterial endothelial cells. RESULTS: In all three IH groups serum levels of TNF-α, IL-8 and IL-6 showed consecutive increment from onset to the 6th week under intermittent hypoxia; the levels of TNF-α and IL-8 dropped slightly on the 8th week, whereas those of IL-6 continued to increase. The levels of IL-10 decreased and reached nadir at the 6th week of intermittent hypoxia treatment. The inflammatory response was the most pronounced in the 6th week, at which time the TNF-α, IL-8 and IL-6 levels in IH groups were significantly higher than in the SC and SH group (F = 30.04, 11.77, 18.589; p <0.05). IL-10 levels were significantly lower than the SC and SH group (F = 10.403, p <0.05). Levels of TNF-α and IL-8 in the IH-1 group were significantly higher than those in the IH-3 group (F = 1.20, 34.68; p = 0.049, 0.046). Protein levels of phosphorylated NF-κB P65 in endothelial cells collected from thoracic aorta in all three IH groups were significantly higher than those in SC and SH groups (F = 63.136, p = 0.01). A close correlation was identified between NF-κB p65 phosphorylation and the levels of TNF-α, IL-8, IL-6 and IL-10 (p = 0.01). CONCLUSIONS: The inflammatory response, manifested by serum levels of inflammatory factors and nuclear accumulation of activated NF-κB P65, was more serious in the IH group than in the SH and control group, and was dependent on hypoxia levels. This reaction increased initially and then decreased, which indicates the presence of compensatory mechanisms and an adaptive response to such stressors in the body. Notably, the correlation of NFκB activation to production of inflammatory factors under intermittent hypoxia implies an important role of this transcription factor in inflammation-induced cardiovascular damage occurring during obstructive sleep apnoea (OSA), which has a typical breathing pattern of intermittent hypoxia.

[Magnetic resonance imaging of the ocular motor nerves in normal volunteers].

OBJECTIVE: To display the detail functional anatomy of ocular motor nerves in the orbits, cavernous sinus and brainstem by high-resolution MRI. METHODS: Twenty normal subjects between 24 and 38 years of age, mean age was 28.25 +/- 4.07 (SD). Imaging of the ocular motor nerves at the brainstem was performed in 0.8 mm thickness image planes using 3D-FIESTA sequence; nerves in the cavernous sinus was imaged with a head coil, the FSE/T(1)WI was obtained in coronal planes; nerves to extraocular muscles (EOMs) in the orbits were imaged with FSE/T(1)WI oblique-coronal planes using surface coils, and within 2.0 mm thick planes. A human orbit was celloidin embedding and serially sectioned at 0.1 mm of thickness for HE stain, which would be used to distinguish motor nerves to the EOMs. RESULTS: Oculomotor nerves (CN3) and abducens (CN6) of the cisternal segment were well demonstrable in all normal subjects. Trochlear nerves (CN4) were depicted 95%. CN3 could be demonstrated consistently in the cavernous sinus, because of their small diameter, CN4 and CN6 not always detectable. The larger inferior division of CN3 and branches to the target EOMs and CN6 were demonstrated well in all species. The superior division of CN3 was demonstrated 60%, CN4 was showed 40%. CONCLUSION: 3D-FIESTA Sequence combined with MPR (Multiplanar Reformation) could precisely show the ocular motor nerves, as well as the relationships with adjacent structures in the cistern. The inferior division of CN3 and the CN6 could be well depicted in the orbits. But of the small sizes and complicated neighboring structures in the orbit, the superior division of the CN3 and the CN4 could not be demonstrated consistently. The capabilities of MRI can be fully used only with thorough knowledge of the complicated topographic relationships in the corresponding region.

Magnetic resonance imaging of the extraocular muscles and corresponding cranial nerves in patients with special forms of strabismus.

BACKGROUND: With the technical advances, magnetic resonance imaging (MRI) is now sensitive enough to detect subtle structural abnormalities of ocular motor nerves arising from the brainstem and orbits of living subjects. This study was designed to delineate the MRI characteristics in patients with special forms of strabismus. METHODS: A total of 29 patients with special forms of strabismus underwent orbital and intracalvarium MRI. Imaging of the ocular motor nerves in the brainstem was performed in 0.8 mm thickness image planes using the three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequence. Nerves to extraocular muscles (EOMs), EOMs and their associated connective tissues were imaged with T1 weighting in tri-planar scans by dual-phased coils within 2.0 mm thick planes. RESULTS: Patients with congenital fibrosis of the extraocular muscles exhibited hypoplasia of the oculomotor (CN3), abducens (CN6), trochlear (CN4) nerves, and the EOMs; hypoplasia of CN6 in the brainstem and an extra branch of the inferior division of CN3 to the lateral rectus were the most common but not the only presentation of Duane's retraction syndrome. Hypoplasia of CN6, facial (CN7) and hypoglossal (CN12) nerves were revealed in patients with Möbius syndrome. In a rare case of bilateral synergistic convergence and divergence, an enlarged branch of CN3 to the medial rectus and a questionable branch of CN3 to the inferior rectus bilaterally were found. CONCLUSION: MRI can reveal subtle structures of the ocular motor nerves and their corresponding EOMs. This can provide valuable information regarding pathogenesis in some special forms of strabismus.

[Computerized three-dimensional reconstruction of the human rectus EOM pulley].

OBJECTIVE: To establish 3-D visible human model of the rectus EOM Pulley. METHODS: The pictures of Masson stained adjacent coronal sections of a whole orbit were imaged by digital camera, which were entered into computer continuously after removing spottiness through PhotoShop 7.0 software. 3D-Doctor software was used to register and split the image. Finally three-dimensional computerized reconstructions of the rectus EOM pulley and eye ball were achieved. At the same time pulley system structure was analyzed using the 3D-Doctor software. RESULTS: Three-dimensional model of the rectus EOM pulley displayed directly the three-dimensional relationship of pulley and the eye ball, extraocular muscles and orbit. This three-dimensional model could be rotated randomly, providing convenience for multi-angle observation. The demonstration of the three-dimensional model selectively provides a approach to get rid of disturbance and lock the aim for observation. The length of pulley was about 4.6 to 5.8 mm. The origin of the four rectus pulleys was 13.8 to 18.0 mm from the corneoscleral limbus. Media rectus pulley was thickest among four rectus pulley. The ratio between media rectus pulley thickness and corresponding media rectus thickness could reach 1.11. CONCLUSIONS: Three-dimensional model of the rectus EOM pulley provided direct picture for clinic doctors to understand the structure of pulley, which also provided three-dimensional anatomic basis for iconography research of the rectus EOM pulley. The data of pulley could be helpful to establish Chinese rectus EOM pulleys data bank.

[Three-dimensional distribution and histological studies of extraocular muscle Pulley in human orbit].

OBJECTIVE: To study the structure and three-dimensional distribution of extraocular muscle Pulley in orbit. METHODS: 5 fresh cadaver orbits were fixed in situ and serially sectioned at 4 microm thickness. Every nearby sections were stained using Masson's trichrome, Van Gieson'stain and immunohistochemical staining, the stained tissue was examined by gross anatomy and light microscopy. RESULTS: Near the equator of the globe, extraocular muscle Pulleys were at the points where rectus penetrate posterior Tenon's fascia, encircling the rectus orbit side by fiber ring structure. There was Pulley Band among extraocular muscle Pulleys. The main composition of the Pulley and Pulley Band were collagen (I and III type), elastic and smooth muscle. CONCLUSION: Constitution of Pulley provides dissection basis as the functional origins of the extraocular muscle.