[Situs inversus of the optic nerve. A case report]. / Situs inversus del nervio optico. A proposito de un caso.

INTRODUCTION: Situs inversus of the optic nerve is a congenital anomaly characterised by the emergence of the vessels in the retina towards the nose rather than in a temporal direction. It is caused by an anomalous insertion of the optic stalks into the optic vesicle that gives rise to dysversion of the head of the optic nerve. It is not an isolated condition and usually appears jointly with tilted disc syndrome and in patients with myopia. It is characterised by the presence of inferior conus atrophy, deficiencies in the temporal visual field, refraction defects and ambliopy. CASE REPORT: A 22 years-old female who attended an ophthalmological examination due to severe frontal headaches accompanied by halos and loss of sharpness in her sight. From the results of the ophthalmetric and ophthalmological examination she was diagnosed as suffering from a condition consistent with this congenital anatomical anomaly. CONCLUSIONS: Situs inversus of the optic nerve is a rare condition that may appear in isolation or accompanied by other pathologies. Application of the visual field test and new diagnostic techniques, such as optical coherence tomography, facilitates the differential diagnosis of this situation. Its prevalence remains unknown, as it is not included in the register of rare diseases. Moreover, the scant number of patients studied and the scarce literature on this anomaly do not allow us to know whether the defects it causes develop over time. It would therefore be important to perform an ophthalmological follow-up of patients with situs inversus of the optic nerve.

TITLE: Situs inversus del nervio optico. A proposito de un caso.Introduccion. El situs inversus del nervio optico es una anomalia congenita caracterizada por la emergencia de los vasos de la retina en direccion nasal en lugar de temporal. Es causado por una anomala insercion del tallo optico en la vesicula optica que da lugar a la variacion de disposicion de la cabeza del nervio optico. No es una condicion aislada y suele aparecer junto con el sindrome del disco inclinado y en pacientes con miopia. Se caracteriza por la presencia de un cono de atrofia inferior, defectos en el campo visual temporal, defectos de refraccion y ambliopia. Caso clinico. Mujer de 22 años, que acude a revision oftalmologica por presentar fuertes cefaleas frontales acompañadas de halos y perdida de nitidez en la vision. Tras un examen optometrico y oftalmologico se llega al juicio clinico de que padece un cuadro compatible con esta anomalia anatomica congenita. Conclusiones. El situs inversus del nervio optico es una condicion rara que puede aparecer aislada o acompañada de otras patologias. La aplicacion de la campimetria y de nuevas tecnicas diagnosticas, como la tomografia de coherencia optica, facilita el diagnostico diferencial de esta situacion. No se conoce su prevalencia, pues no se encuentra en el registro de las enfermedades raras. Ademas, el escaso numero de pacientes estudiados y la exigua bibliografia existente sobre esta anomalia no permiten conocer si los defectos causados progresan en el tiempo, por lo que seria importante realizar un seguimiento oftalmologico de los pacientes con situs inversus del nervio optico.

Substance P and calcitonin gene-related peptide intrinsic choroidal neurons in human choroidal whole-mounts.

To determine the presence in the human choroid of substance P (SP)-and calcitonin gene-related peptide (CGRP) positive intrinsic choroidal neurons (ICNs), choroidal whole-mounts were processed for indirect immunofluorescence. An antibody to a component of the neuronal cytoskeleton, neurofilament 200 kDa (NF-200), was combined with antibodies to SP and to CGRP (neuropeptides proper to the sensory nervous system). The human choroid possesses numerous SP(+) and CGRP(+) ICNs. These neurons were observed in the suprachoroid, both in isolation and forming microganglia. For both types of ICNs studied, neurons were more numerous in the temporal than in the nasal regions. In both locations, SP(+) and CGRP(+) ICNs were more abundant in the central choroid (the choroid underneath the macular area of the retina), with cell density diminishing outwards to the choroidal periphery. There were no appreciable differences between the two populations of ICNs studied in terms of size, morphology or immunostaining characteristics. In conclusion, given that peripheral sensory innervation could be involved in the regulation of both choroidal blood flow and vascular architecture, the SP(+) and CGRP(+) ICNs described for the first time in the present work may be involved in these mechanisms of vascular regulation.

[A comparative study of choroidal innervation in the human and the rabbit (oryctolagus cuniculus)]. / Estudio comparativo de la inervación coroidea en el hombre y en el conejo (oryctolagus cuniculus).

OBJECTIVE: To analyze morphological differences between the choroidal innervation of the human and the rabbit, the latter being a species frequently used as an experimental model of human ocular diseases. METHODS: Twelve human and 12 rabbit choroidal whole mounts were processed using an indirect immunohistochemical technique, peroxidase-anti-peroxidase and antibodies against 200 kD neurofilament. RESULTS: Choroidal nerve fibers were perivascular and intervascular. Perivascular fibers surrounded all arteries forming a network that was more developed in the rabbit. In humans, intervascular fibers were mainly concentrated at the posterior pole where they formed a denser and more highly organized plexus than in the rabbit, which did not exhibit a preferential location for these fibers. Human choroidal ganglion cells were far more numerous than in the rabbit and were concentrated in a circumferential area corresponding to the entrance of the short posterior ciliary arteries of the submacular area. In the rabbit, these cells were restricted to the peripheral choroid. CONCLUSIONS: Some differences were observed between human and rabbit choroidal innervation. The abundance of ganglion cells and their preferential distribution could be necessary to maintain a constant blood flow in the central area of the human choroid. The lack of organization of rabbit choroidal innervation at the posterior pole could be associated with an absence of the macula. These differences, along with peculiarities of retinal vascularization, should be taken into consideration when using the rabbit as an experimental model to study human eye diseases in which regulation of choroidal blood flow is involved.

[Structural changes of the anterior chamber angle in primary congenital glaucoma with respect to normal development]. / Cambios estructurales del ángulo de la cámara anterior en el glaucoma congénito. Comparación con el desarrollo normal.

PURPOSE: To compare findings of normal angles with those from primary congenital glaucoma in order to clarify the pathogenic mechanisms of the disease and to explain the success of surgical treatment in some of these patients. METHODS: Adult normal eyes from cadavers and fragments of surgical trabeculectomies from patients with primary congenital glaucoma previously treated with goniotomy were studied. Eyes were processed for examination using light microscopy and scanning electron microscopy techniques. RESULTS: The following was evident in congenital glaucoma: 1) high iris insertion; 2) no observable pre-trabecular membrane, but enlarged trabeculae with diminished inter-trabecular spaces; 3) Schlemm's canal (SC) apparently normal, with vacuoles in the wall indicating normal functioning; 4) sectioning of the abnormal trabecular tissue during goniotomy allowed repositioning of the angle structures and hence the appearance of the angular recess. CONCLUSIONS: Anomalies of the trabecular structures in primary congenital glaucoma do not always parallel an abnormal development of the SC and the collector channels. This fact could explain the success of goniotomy in this type of glaucoma.

Cambios estructurales del ángulo de la cámara anterior en el glaucoma congénito. Comparación con el desarrollo normal / Structural changes of the anterior chamber angle in primary congenital glaucoma with respect to normal development

Objetivo: Comparar los hallazgos morfológicosobservados en ángulos normales con los observadosen ángulos de pacientes con glaucoma congénitoprimario, para intentar clarificar los mecanismospatogénicos de esta enfermedad, así como explicarel éxito del tratamiento quirúrgico en alguno deestos pacientes.Métodos: Se utilizaron ojos adultos normales procedentesde cadáveres y fragmentos quirúrgicosprocedentes de trabeculectomías, de pacientes conglaucoma congénito primario que habían sido tratadospreviamente con una goniotomía. Los tejidosfueron procesados para su examen a microscopíaóptica (MO) y microscopía electrónica de barrido(MEB).Resultados: En los glaucomas congénitos encontramos:1) inserción alta del iris; 2) No se observauna membrana pre-trabecular, sino que comparandocon los ángulos normales las trabéculas aparecenensanchadas con disminución de los espacios intertrabeculares; 3) el canal de Schlemm (CS) es aparentementenormal, con vacuolas en su pared queindican un funcionamiento normal del mismo; 4) lasección del tejido trabecular anormal que producela goniotomía, permite el reposicionamiento de lasestructuras del ángulo y por tanto la aparición delreceso angular.Conclusiones: En el glaucoma congénito primariolas anomalías de las estructuras trabeculares nosiempre se acompañan de un desarrollo anómalodel CS y de los canales colectores. Este hechopodría explicar que la goniotomía sea un tratamientocon éxito en estos glaucomas

Purpose: To compare findings of normal angles ;;with those from primary congenital glaucoma in ;;order to clarify the pathogenic mechanisms of the ;;disease and to explain the success of surgical treatment ;;in some of these patients. ;;Methods: Adult normal eyes from cadavers and ;;fragments of surgical trabeculectomies from ;;patients with primary congenital glaucoma previously ;;treated with goniotomy were studied. Eyes ;;were processed for examination using light microscopy ;;and scanning electron microscopy techniques. ;;Results: The following was evident in congenital ;;glaucoma: 1) high iris insertion; 2) no observable pretrabecular ;;membrane, but enlarged trabeculae with ;;diminished inter-trabecular spaces; 3) Schlemm’s ;;canal (SC) apparently normal, with vacuoles in the ;;wall indicating normal functioning; 4) sectioning of ;;the abnormal trabecular tissue during goniotomy allowed ;;repositioning of the angle structures and hence ;;the appearance of the angular recess. Conclusions: Anomalies of the trabecular structures ;;in primary congenital glaucoma do not always ;;parallel an abnormal development of the SC and the ;;collector channels. This fact could explain the success ;;of goniotomy in this type of glaucoma

NPY and TH innervation in human choroidal whole-mounts.

To determine the distribution of NPY and TH human choroidal innervation, choroidal whole-mounts were processed for indirect immunofluorescence. An antibody to a component of the neuronal cytoskeleton, neurofilament 200 kDa (NF-200) was used to identify neurons and axons. A double immunostaining was performed, antibodies against NF-200 being combined with antibodies against neuropeptide Y (NPY) and tyroxine hydroxylase (TH). Fibers containing both NPY and TH were distributed in three plexuses, one in the suprachoroid large-sized vessel layer, and two in the medium-sized vessel layer. Intrinsic choroidal neurons (ICNs) containing NPY and TH were observed in the suprachoroid. The TH(+) ICNs were located in the medium-sized vessel layer. Overall, NPY(+) and TH(+) ICNs were more frequent in the central temporal area, both in isolation and forming microganglia. We also detected small spindle elements intensely immunoreactive to TH(+) and distributed mainly in the suprachoroid from the equator to the periphery. In conclusion, the human choroid contains abundant NPY and TH nerve fibers related to chroroidal vascular structures; it further possesses NPY(+) and TH(+) ICNs which contribute to the choroidal self-regulation persisting after sympathetic denervation. Additionally, these ICNs may at least partially explain why the choroidal blood flow does not respond to the factors that influence systemic vascular control. The preferential location of these cells in the submacular area suggests that dysfunction or degeneration of these cells may be a factor in vascular pathologies found in ocular disease, such as diabetic macular edema or age-related macular degeneration.

Changes of astrocytes in retinal ageing and age-related macular degeneration.

Most studies of age-related macular degeneration (AMD) have focused on the outer retina but little has been done on the involvement of astrocytes in this disease. We examined normal (young and old) and pathological (AMD) human retinas for the presence of changes in morphology and distribution of the astrocytes. Electron microscopy and inmunohistochemical techniques (anti-GFAP) were used for this study. Astrocytes in the ageing group showed: (1) higher GFAP immunoreactivity and more cytoplasmic organelles and glial filaments than astrocytes from younger retinas; (2) lipofucsin deposits; (3) a significantly smaller number of cells in the honeycomb astroglial plexus in the ganglion cell layer than in the younger group; and (4) Spaces with no GFAP reactivity in the nerve fiber layer. Changes observed in the AMD group were: (1) the basal membrane of the retinal capillaries was considerably thicker than in normal old individuals; (2) There were numerous non-functional capillaries; (3) There were hypertrophic astrocytes that phagocytosed dead ganglion cells; and (4) There were glial membranes constituted by astrocytes and Müller cells located between the vitreous humour and internal limiting membrane. These observations suggested that the extensive retinal ischaemia that can occur with AMD, together with the loss of astroglial cells accompanying normal ageing, could cause the death of the ganglion cells which cannot be protected from oxidative damage. Extensive ischaemia could cause the astrocytes to migrate to the vitreous humour where there is a metabolic reserve.

Immunohistochemical study of rabbit choroidal innervation.

Immunocytochemical methods with antibodies to the light (68 kDa), medium (160 kDa), and heavy (200 kDa) chain subunits of the neurofilament triplet have been used to visualize neuronal structures in rabbit choroids. Choroidal nerve fibers were present in the suprachoroid and vascular laminae and absent in the choriocapillary layer. These fibers may be classified as perivascular and intervascular. Perivascular fibers surround all arterial and venous blood vessels and form a network; these fibers were labeled with the three NF antibodies, although they were more easily visualized with anti NF-160 and anti NF-200 than anti NF-68. Intervascular fibers formed two groups. The first group consisted of fibers situated between the blood vessels and parallel to the blood vessel wall surface (paravascular fibers); these fibers were better observed using anti NF-160 and NF-200 than anti NF-68. The second group consisted of fibers which travel the entire length of the choroid until they reach the nerve plexus of the ciliary body (long tract fibers). The plexus was observed with anti NF-68, anti NF-160 and anti NF-200; however, the long tract fibers were more clearly visualized with anti NF-160 and anti NF-200 than with anti NF-68. Two types of choroidal cell were also labeled: ganglion cells and melanocytes. Ganglion cells are small, scarce neurons situated in the peripheral choroid; they were labeled with anti NF-160 and anti NF-200. The melanocytes were only labeled with anti NF-200 and they were the only non neuronal structure visualized using antibodies against neurofilaments.