Fibrosis congénita de los músculos extraoculares / Congenital Fibrosis of Extraocular Muscles

La fibrosis congénita de los músculos extraoculares se caracteriza por una oftalmoplejía externa congénita, no progresiva, generalmente bilateral, con ptosis y alteración de los movimientos oculares. Existen varios tipos en dependencia del gen afectado y puede estar acompañada de hallazgos adicionales tanto oculares como generales. Para el manejo de los casos se realiza cirugía de la ptosis, alineación ocular y corrección del torticolis, además de su corrección óptica y rehabilitación para maximizar el resultado visual. Con el objetivo de estar al día sobre esta enfermedad se realiza una revisión de las publicaciones de los últimos cinco años en este tema. Actualmente no hay tratamientos que puedan restaurar la funcionalidad completa y el rango de movimiento de los músculos extraoculares, pero mejorar su funcionalidad visual es primordial(AU)

Congenital fibrosis of the extraocular muscles is characterized by congenital external ophthalmoplegia, nonprogressive, usually bilateral, with ptosis and altered eye movements. There are several types depending on the affected gene and it may be accompanied by additional ocular or general findings. For the management of these cases, ptosis surgery, ocular alignment and torticollis correction are performed, as well as optical correction and rehabilitation to maximize visual outcome. In order to be updated about this disease, a review of the publications on this subject within the last five years is carried out. Currently, there are no treatments that can restore full functionality and range of motion of the extraocular muscles, but improving their visual functionality is paramount(AU)

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography.

PURPOSE: To assess the agreement between the measurements of the distance from the medial rectus muscles insertion to the limbus measured by intra-operative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT). METHODS: An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation. RESULTS: Mean age was 36.3 ± 16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7 ± 16.9 prismatic dioptres (PD) (range 16-65), being +1.3 ± 6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7 ± 2.1 mm (range 5.5-12.0) and by OCT at 7.7 ± 1.2 mm (range 5.3-10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; p < 0.001), with a correlation of R = 0.792 (p = 0.011). A better agreement was observed in those MR that were less retro-inserted. CONCLUSIONS: SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Overall distribution pattern of the intramuscular nerves of the extraocular muscles and its clinical implications / Patrón de distribución general de los nervios intramusculares de los músculos extraoculares y sus implicaciones clínicas

SUMMARY: The purpose of this study was to reveal the overall distribution pattern of the intramuscular nerves of each extraocular muscle and provide morphological guidance for the selection of the neuromuscular compartment during extraocular muscle transplantation and target localization of the botulinum toxin A injection to correct strabismus. We studied 12 Chinese head specimens that were fixed with formalin. The extraocular muscles from both sides of each head were removed, and a modified Sihler's staining technique was used to reveal the overall distribution pattern of the intramuscular nerves. We observed an intramuscular nerve-dense region formed by the intramuscular arborized branches in the semitransparent superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, and levator palpebrae superioris muscles with Sihler's staining technique. The seven extraocular muscles can each be divided into two neuromuscular compartments. The intramuscular nerve-dense regions of the superior, inferior, medial, and lateral rectus and the superior oblique, inferior oblique, and levator palpebrae superioris muscles were positioned at 33.50 % -72.72 %, 40.21 % - 66.79%, 37.92 % - 64.51 %, 31.69 % - 56.01 %, 26.35 % - 64.98 %, 40.46 % - 73.20 %, and 27.72 % - 66.07 % of the lengths of the muscle bellies, respectively, and the centers of intramuscular nerve dense regions were located at 59.50 %, 54.18 %, 51.68 %, 50.08 %, 48.38 %, 56.49 %, and 50.77 % of the length of each muscle belly, respectively. The aforementioned values are the means of the actual values. These results suggest that when the strabismus is corrected with muscle transplantation, the extraocular muscle should be transplanted based on the neuromuscular compartment, which would benefit the function of both donor and recipient muscles. The localization of these nerve dense regions is recommended as an optimal target for the injection of botulinum toxin A to treat strabismus.

RESUMEN: El objetivo de este estudio fue revelar el patrón de distribución de los nervios intramusculares de cada músculo extraocular y, proporcionar una guía morfológica para la selección del compartimento neuromuscular durante el trasplante de músculo extraocular, y la localización de la inyección de toxina botulínica A para corregir el estrabismo. Estudiamos 12 muestras de cabezas de individuos chinos fijadas en formalina. Se extrajeron los músculos extraoculares de ambos lados de cada cabeza y, se utilizó una técnica de tinción de Sihler modificada para revelar el patrón de distribución general de los nervios intramusculares. Observamos una región densa en nervios intramusculares formada por los ramos intramusculares en los músculos recto superior semitransparente, recto inferior, recto medial, recto lateral, oblicuo superior, oblicuo inferior y elevador del párpado superior con técnica de tinción de Sihler. Los siete músculos extraoculares se pueden dividir cada uno en dos compartimentos neuromusculares. Las regiones intramusculares densamente nerviosas de los músculos recto superior, inferior, medial y lateral y los músculos oblicuo superior, oblicuo inferior y elevador del párpado superior se colocaron en 33,50 % -72,72 %, 40,21 % -66,79 %, 37,92 % -64,51 % , 31,69 % -56,01 %, 26,35 % -64,98 %, 40,46 % -73,20 % y 27,72 % -66,07 % de las longitudes de los vientres musculares, respectivamente, y los centros de las regiones densamente nerviosas intramusculares se ubicaron en 59,50 %, 54,18 % , 51,68 %, 50,08 %, 48,38 %, 56,49 % y 50,77 % de la longitud de cada vientre muscular, respectivamente. Los valores antes mencionados son medios de los valores reales. Estos resultados sugieren que cuando el estrabismo se corrige con trasplante de músculo, el músculo extraocular debe trasplantarse en función del compartimento neuromuscular, lo que beneficiaría la función tanto de los músculos donantes como receptores. Se recomienda la localización de estas regiones densas en nervios, como un objetivo óptimo para la inyección de toxina botulínica A para tratar el estrabismo.

Evaluación de la distancia al recto medio en la exotropía consecutiva mediante tomografía de coherencia óptica y medida intraoperatoria / Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography

Propósito Valorar la concordancia de la medición intraoperatoria de la distancia de la inserción del recto medio (RM) al limbo corneal con la obtenida preoperatoriamente mediante tomografía de coherencia óptica de dominio espectral (SD-OCT) en pacientes con exotropía consecutiva (XTc). Métodos Se analizaron 14RM de 14 pacientes con XTc posquirúrgica que iban a ser reintervenidos. La distancia inserción-limbo fue medida preoperatoriamente mediante SD-OCT y de forma intraoperatoria con compás. Se calculó el coeficiente de correlación intraclase y un análisis de Bland Altman para analizar la concordancia de las medidas, estudiándose además la correlación de las mismas. Resultados La edad media fue 36,3±16,0años (rango 13-60), siendo el 57% mujeres. La desviación ocular media preoperatoria de la XT fue 38,7±16,9 dioptrías prismáticas (DP) (rango 16 a 65), siendo el resultado tras la cirugía de +1,3±6,3 DP (rango –12 a +10 DP). Intraoperatoriamente se halló la inserción del RM a 8,7±2,1mm (rango 5,5-12,0) y con OCT a 7,7±1,2mm (rango 5,3-10,0). El cociente de correlación intraclase mostró una concordancia moderada-buena (0,659; intervalo de confianza al 95%: 0,157-0,885; p<0,001), hallándose una correlación de R=0,792 (p=0,011). Se observó una mayor concordancia en aquellos RM que se hallaban menos retroinsertados. Conclusiones La SD-OCT puede ser una técnica útil para valorar la distancia de la inserción al limbo corneal de los RM previamente retroinsertados, hallándose una concordancia moderada-buena con la medida intraoperatoria. Sin embargo, la concordancia fue baja en músculos muy retroinsertados (AU)

Purpose To assess the agreement between the intraoperative measurements of the distance from the medial rectus muscles insertion to the limbus and preoperative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT). Methods An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation. Results Mean age was 36.3±16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7±16.9 prismatic dioptres (PD) (range 16 to 65), being +1.3±6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7±2.1mm (range 5.5 - 12.0) and by OCT at 7.7±1.2mm (range 5.3 - 10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; P<.001), with a correlation of R=0.792 (P=.011). A better agreement was observed in those MR that were less retro-inserted. Conclusions SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion (AU)

Evaluation of the insertion distance of the medial rectus in consecutive exotropia by means of intraoperative measure and optical coherence tomography. / Evaluación de la distancia al recto medio en la exotropía consecutiva mediante tomografía de coherencia óptica y medida intraoperatoria.

PURPOSE: To assess the agreement between the intraoperative measurements of the distance from the medial rectus muscles insertion to the limbus and preoperative spectral-domain optical coherence tomography (SD-OCT) in consecutive exotropia (cXT). METHODS: An analysis was performed on total of 14 medial rectus (MR) muscles of 14 patients who underwent surgery for the treatment of cXT. The limbus-insertion distance of the MR muscles was measured using preoperative SD-OCT and intraoperatively using a calliper. The intraclass correlation coefficient (ICC) and Bland Altman plots were calculated to determine the agreement between the two methods, as well as the correlation. RESULTS: Mean age was 36.3±16.0 years (range 13-60), with 60% being women. Mean preoperative deviation was 38.7±16.9 prismatic dioptres (PD) (range 16 to 65), being +1.3±6.3 PD (range -12 to +10 PD) after surgery. Intraoperatively the MR insertion was found at 8.7±2.1mm (range 5.5 - 12.0) and by OCT at 7.7±1.2mm (range 5.3 - 10.0). The ICC showed a moderate to good agreement (0.659; 95% confidence interval: 0.157-0.885; P<.001), with a correlation of R=0.792 (P=.011). A better agreement was observed in those MR that were less retro-inserted. CONCLUSIONS: SD-OCT is able to measure the insertion to the limbus distance of the medial rectus muscles that have been previously operated on, showing moderate to good agreement with intraoperative measurements. However, the agreement was poor in muscles with a large retro-insertion.

Inestabilidad de la polea como causa de estrabismo / Pulley instability as a cause of strabismus

RESUMEN La caracterización de las poleas de los músculos extraoculares ha sido de gran trascendencia en la fisiopatología del equilibrio óculo-motor. El efecto mecánico de la polea funcional es cambiar el eje de acción del músculo de acuerdo con la orientación que el globo ocular presente. Los trastornos en la localización o estabilidad de las poleas pueden crear patrones de estrabismo incomitante. Es importante el conocimiento de estas anomalías porque los procedimientos quirúrgicos estándar no corrigen los desplazamientos de las poleas. Se realizó una búsqueda del tema de los últimos 10 años utilizando la plataforma de infomed(AU)

ABSTRACT Characterization of extraocular muscle pulleys has had great relevance in the physiopathology of ocular motor balance. The mechanical effect of the functional pulley is to change the axis of action of the muscle in keeping with the orientation of the eyeball. Pulley location or stability disorders may create incomitant strabismus patterns. It is important to be aware of these anomalies because standard surgical procedures do not correct pulley displacement. A search was conducted on the Infomed platform of papers published about the topic in the past ten years(AU)

Response to tocilizumab treatment in Graves' ophthalmopathy by measuring rectus muscle thickness and chemosis using optical coherence tomography. / Evaluación del grosor de los músculos extraoculares y la quemosis tras tocilizumab en oftalmopatía de Graves mediante tomografía de coherencia óptica.

PURPOSE: To assess the extraocular muscle thickness and chemosis after treatment with tocilizumab in patients with active Graves' ophthalmopathy by optical coherence tomography. METHODS: Case series of five patients with active Graves' ophthalmopathy (clinical activity score ≥4/10) treated with 4 doses of tocilizumab. These patients had been previously treated with corticosteroids with no response. Spectral-domain optical coherence tomography was employed to determine lateral and medial rectus muscle thickness and chemosis before and after 4 doses of tocilizumab given monthly. Scanning was performed at 3 and 9 o'clock (nasal and temporal). RESULTS: The study included four women and one man with a median age of 52 years (range: 38-73). Median Graves' ophthalmopathy activity duration was 17 months (12-18). Median medial rectus and determine lateral thicknesses pre-treatment were 249µm (174-366) and 337µm (142-443), respectively. Median chemosis was 409µm (290-610). After tocilizumab treatment, median muscle thicknesses reduced to 157µm (88-187) and 197µm (99-290), respectively (P=.043; Wilcoxon) and chemosis to 59µm (0-78). Median clinical activity score decreased from 5 (4-8) to 1 (0-3). CONCLUSIONS: A reduction in extraocular muscle thickness and chemosis was observed after treatment with tocilizumab in Graves' ophthalmopathy patients using an optical coherence tomography, so this technique could be a useful complementary technique to assess the therapeutic responses.

Assessment of extraocular muscle thickness and correlation study using optical coherence tomography. / Evaluación del grosor de los músculos extraoculares y estudio de correlación mediante tomografía de coherencia óptica.

OBJECTIVE: To report reference values for the horizontal rectus muscles thickness using Spectral Domain optical coherence tomography (SD-OCT), and to evaluate whether there are any correlations between the muscle thickness and gender, age, or axial length (AL). MATERIAL AND METHODS: A cross-sectional study was conducted on 131 right eyes of healthy subjects. The gender and age were recorded, and axial length was measured using an optical biometer. The medial rectus (MR) muscle thickness was measured at 7.2 and 9.2mm from the limbus, and the lateral rectus (LR) at 8.5 and 10.5mm from the limbus using OCT. A multivariate model was adjusted to determine whether gender, age, and axial length could have an impact on the muscle thickness. RESULTS: Mean age was 43.3±20.9 years (range 6-86), and 59% were women. Mean AL was 24.9±2.7mm (range: 20.4-33.8). Mean thickness was 188.5±51.2µm (range 69-342) for the LR at 8.5 and 186.5±45.9µm (range 75-269) at 10.5mm, and for the MR, 158.1±39.1µm (range 69-273) at 7.2mm and 193.7±55.9µm (range 105-386) at 9.2mm. A correlation was observed between the AL and MR thickness (R=-.255; P=.023) while no correlation was observed for the LR (P≥0.203). No correlations were found between thickness and gender or thickness and age (P≥0.125). CONCLUSIONS: The reference ranges of the horizontal rectus muscles thickness was described using SD-OCT, observing an association between the AL and the MR thickness.

Agreement between intraoperative measurements and optical coherence tomography of the limbus-insertion distance of the extraocular muscles. / Concordancia de la distancia desde la inserción hasta el limbo de los músculos rectos entre la medida intraoperatoria y con tomografía de coherencia óptica.

OBJECTIVE: To assess the agreement between intraoperative measurements of the limbus-insertion distance of the extraocular muscles with those measured by spectral domain optical coherence tomography. METHODS: An analysis was made of a total of 67 muscles of 21 patients with strabismus. The limbus-insertion distance of the horizontal rectus muscles were measured using pre-operative SD-OCT and intra-operatively in 2 ways: 1) direct, after a conjunctival dissection in patients who underwent surgery, or 2) transconjunctival in patients who were treated with botulinum toxin, or in those who were not going to be operated. The intraclass correlation coefficient and Bland-Altman plots were calculated to determine the concordance between the 2 methods. RESULTS: The mean age was 45.9 ±20.9 years (range 16 to 85), with 52% being women. The percentage of identification by direct intraoperative measurement was 95.6% (22/23), by transconjunctival intraoperative measurement 90.9% (40/44), and by OCT 85% (57/67), with 22 muscles finally being analysed for the agreement study between direct intraoperative measurement and OCT measurements, and 35 muscles for the agreement between transconjuctival intraoperative measurement and OCT. The intraclass correlation coefficient showed good agreement with OCT and direct intraoperative measurements (0.931; 95% confidence interval (95% CI): 0.839-0.972; P<.001), and with transconjunctival intraoperative measurements (0.889; 95% CI: 0.790-0.942; P<.001). CONCLUSIONS: The SD-OCT is an effective technique to measure the distance from the insertion of the horizontal rectus muscles to the limbus, with a high agreement with intraoperative measurements being demonstrated.

A morphometric study of the extraocular muscles / Estudio morfométrico de los músculos extraoculares

Extraocular muscles are important references in strabismus surgery and in placement of intraorbital devices. We analyzed extraocular muscles morphometry and possible anatomical variances of 20 orbits. We report the length, width, and points of insertion of the extraocular muscles. No anatomical variations in length, width and points of insertion were found. With regard to the rectus muscles, it was found that the superior rectus and lateral rectus are the longest muscles and that the width difference between the superior and inferior rectus is greater than that between the medial and lateral rectus and that the point of insertion of the rectus muscles has a variable morphology. The superior oblique muscle was smaller in caliber than the inferior oblique, as consistent with previous anatomical studies. Knowledge of the detailed morphology of extraocular muscles is fundamental in strabismus surgery and represents a key factor for the innovation of surgical techniques and orbital procedures.

Los músculos extraoculares son importantes en la cirugía de estrabismo y en la colocación de dispositivos intraorbitarios. Analizamos la morfometría de los músculos extraoculares y las posibles variaciones anatómicas en 20 orbitas. No encontramos variantes en longitud, anchura y sitios de inserción. Los músculos rectos superior y lateral son los mas largos; la diferencia en longitud entre los músculos rectos superior e inferior es mayor a la diferencia en longitud entre los músculos rectos medial y lateral. El músculo oblicuo superior es mas pequeño en calibre que el músculo oblicuo inferior, lo que coincide con otros estudios anatómicos. El conocimiento detallado de la morfología de los músculos extraoculares es fundamental en la cirugía de estrabismo y representa un factor clave para la innovación de técnicas quirúrgicas y procedimientos en la cavidad orbitaria.

Oftalmopatia tireoidea revisitada: [revisão] / Thyroid ophthalmopathy revisited: [review]

A oftalmopatia tireoidea é doença orbitária autoimune intimamente associada com o hipertireoidismo, porém podendo existir separadamente. Pode preceder, coincidir ou suceder o início da disfunção tireoidea, raramente ocorrendo em eutireoideos ou hipotireoideos. Os músculos extraoculares são os principais alvos acometidos e tornam-se aumentados de volume, determinando oftalmoplegia e proptose. Outros sinais importantes incluem retração palpebral, hiperemia conjuntival e edema periorbitário. Perda visual pode ocorrer se há compressão do nervo óptico no ápice orbitário. A oftalmopatia tireoidea é caracterizada por inflamação, congestão, hipertrofia e fibrose da gordura e músculos orbitários. A atividade da doença é dividida em fase aguda ou inflamatória, seguida pela fase inativa associada com alterações fibróticas e infiltração gordurosa. O diagnóstico é clínico, e quando este é difícil ou se suspeita de neuropatia óptica os métodos de imagem são indicados. A tomografia computadorizada e a ressonância magnética podem confirmar o diagnóstico e avaliar a área crítica do ápice orbitário. A ressonância magnética é superior, em virtude da resolução tecidual e da sua capacidade de avaliar a atividade da doença (mediante sequências com TR longo) e detectar alterações inflamatórias, auxiliando o planejamento terapêutico no momento certo, melhorando o prognóstico.

Thyroid ophthalmopathy is an autoimmune orbital disorder closely associated with Graves' disease, although both conditions may also occur isolatedly. Thyroid ophthalmopathy may precede, coincide or follow the thyroid dysfunction onset and may rarely occur in euthyroid and hypothyroid patients. The extraocular muscles are most frequently involved and become enlarged resulting in ophthalmoplegia and proptosis. Other relevant signs include palpebral retraction, conjuctival hyperemia and periorbitary edema. Visual loss may occur in association with compressive optic neuropathy at the orbital apex. Thyroid ophthalmopathy is characterized by inflammation, congestion, hypertrophy and fibrosis involving fat and the orbital muscles. The disease activity is divided into two phases: an acute or inflammatory phase and a second one corresponding to an inactive phase associated with fibrotic changes and fat infiltration of the retrobulbar tissues. The diagnosis is based on clinical findings and imaging methods are indicated in case of doubt or suspicion of optic neuropathy. Computed tomography and magnetic resonance imaging can confirm the diagnosis, allowing the evaluation of the critical region of the orbital apex. Magnetic resonance imaging is the method of choice considering the superior tissue contrast resolution, besides the capacity of evaluating the disease activity by means of long TR sequences and detecting inflammatory changes, with a relevant role in a timely therapeutic planning, which may improve the prognosis.

Alteraciones del sistema nervioso central asociadas a fibrosis congénita de músculos extraoculares / Central nervous system abnormalities related to congenital fibrosis of extraocular muscles

Objetivo: Describir las alteraciones del sistema nervioso central asociadas a dismorfogenesias de los nervios craneales. Material y métodos: Estudio retrospectivo, observacional, transversal y descriptivo de pacientes con estrabismo por fibrosis congénita de los músculos extraoculares, atendidos entre enero de 2001 y enero de 2006. Fueron identificadas las lesiones neurológicas y se analizó su asociación. Resultados: Todos los pacientes tuvieron estrabismos fibróticos. Se incluyeron 16 pacientes, nueve hombres y siete mujeres. Las lesiones neurológicas asociadas fueron anomalías de cuerpo calloso, cortipatía severa con sordera, epilepsia, cavum vergae, nistagmo, quiste subaracnoideo occipital e hidrocefalia. Se demostró retraso psicomotor en 56 % de los pacientes. Se identificaron malformaciones congénitas como trigonocefalia, camptodactilia, hipoplasia facial, implantación baja de orejas. La ptosis palpebral se encontró en 81 % de los casos. El estrabismo más frecuente fue la exotropía (56 %) seguida de hipotropía (37.5 %), hipertropía (18.7 %), anisotropía en “A” (18.7 %) y endotropía (6.25 %). Los nervios craneales afectados fueron el III (93.75 %), VI (6.25 %) y VII (6.25 %); además, se encontró lesión a II nervio en 50 %. Conclusiones: La falla en los estadios tempranos del desarrollo del sistema nervioso central puede provocar estrabismo paralítico que secundariamente puede manifestarse como estrabismo fibrótico que afecta músculos y tejidos orbiculares, por lo que el término más apropiado sería “estrabismo fibrótico congénito como causa de dismorfogenesia de los nervios craneales”. Encontramos alta incidencia de retraso psicomotor y alteraciones neurológicas. Es importante la rehabilitación temprana y multidisciplinaria en estos pacientes.

OBJECTIVE: We undertook this study to describe central nervous system (CNS) abnormalities associated with congenital cranial dysinnervation disorders (CCDD). METHODS: This was a retrospective, observational, transversal and descriptive study including patients with congenital fibrotic strabismus. We analyzed clinical files of patients from 2001 to 2006. Neurological lesions were reported. RESULTS: Restrictive strabismus was demonstrated in all cases. Sixteen patients were included: nine males and seven females. Different neurological lesions were reported: corpus callosum anomalies, severe cortipathy, epilepsy, cavum vergae, nystagmus, occipital subarachnoid cyst, and hydrocephalus. Mental retardation was reported in 56% of patients. Different malformations were reported: genital malformations, trigonocephalus, camptodactyly, mild facial hypoplasia, low set ears, and agenesis of left ear. Blepharoptosis was present in 81% of patients. The most frequent form of strabismus was exotropia (56%), hypotropia in 37.5%, hypertropia 18.7%, "A" pattern 18.7%, and esotropia in 6.25%. Affection was cranial nerve III, 93.75%; cranial nerve VI, 6.25%; cranial nerve VII, 6.25%; and lesion to cranial nerve II in eight cases (50%). CONCLUSIONS: We have suggested that failure in early stages of embryology of the CNS can lead to the development of paralytic strabismus and generate secondary fibrotic changes, not only in muscle structures but also in other orbital tissues. That is the reason why we have used the term "congenital fibrotic strabismus" to report cases included in CCDD. We have demonstrated the strong association of mental retardation and neurological alterations. Multidisciplinary rehabilitation is relevant for these patients.