Refractive features and amblyopia in Duane's Retraction Syndrome: A review of the 582 patients / Características refractivas y ambliopía en el síndrome de retracción de Duane: una revisión de los 582 pacientes

Purpose: To report the visual and refractive characteristics and the prevalence of amblyopia in patients with different types of Duane's Retraction Syndrome (DRS). Method: This retrospective study was performed on hospital records of 582 DRS patients at Farabi Hospital, Iran, from 2012 to March 2022. Results: The mean age of patients was 19.4 ± 11.9 (range, 3–70) years [335 (57.6 %) females and 247 (42.4 %) males (P < .001)]. DRS type I, II, III, and IV were presented in 347 (59.6 %), 148 (25.4 %), 82 (14.1 %), and 5 (0.9 %) patients, respectively. There were 530 (91.1 %) patients with unilateral and 52 (8.9 %) with bilateral involvement. In the unilateral patients, the DRS eyes' corrected distance visual acuity (CDVA) and astigmatism were significantly worse than the Non-DRS Eyes (P < .001). The mean amount of all refractive and visual parameters in bilateral patients' right or left eyes was significantly lower than in unilateral patients' non-DRS eyes (all P < .05). Anisometropia was observed in 75(12.9 %) of the patients. Amblyopia was observed in 18.5 % (98 patients) and 36.5 % (19 patients) of unilateral and bilateral DRS patients, respectively (P < .001). In unilateral patients, amblyopia was found in 57 (16.4 %) patients with Type I, 22 (14.9 %) patients with Type II, 16 (19.5 %) patients with Type III, and 3 (60 %) patients with Type IV. Forty-four (37.6 %) of patients with amblyopia had anisometropia. Conclusion: This large-scale study indicates that DRS types differ in terms of refractive error, visual acuity, and the prevalence of amblyopia and anisometropia. Clinicians should be aware of the clinical features associated with different types of DRS.(AU)

Two cases of Duane retraction syndrome with abnormal orbital structures.

Duane retraction syndrome (DRS) is a rare congenital nonprogressive restrictive strabismus. The absence/hypoplasia of the abducens nerve and the aberrant innervation of the lateral rectus muscle by the oculomotor nerve have been hypothesized as causes of DRS, although the phenomenon of globe retraction can also occur in the setting of mechanical factors, such as congenital abnormal orbital structures or orbital trauma. We present the cases of 2 DRS patients with absent abducens nerve and abnormal muscular bands connecting the superior rectus and inferior rectus muscles on the temporal side of the optic nerve.

Iatrogenic Pseudo-Duane Retraction Syndrome Following Orbitozygomatic Craniotomy.

Restrictive strabismus is a known complication of orbitozygomatic craniotomy. However, a pseudo-Duane syndrome has not been described following this procedure. The authors describe a 58-year-old woman who after craniotomy developed incomitant left exotropia with an adduction deficit; the globe retracted and palpebral fissure narrowed with attempted ocular adduction. [J Pediatr Ophthalmol Strabismus. 2024;61(1):e7-e10.].

The Frequency and Manifestations of Ocular Causes of Abnormal Head Posture.

PURPOSE: To determine the frequency and manifestations of different ocular causes of abnormal head posture (AHP). METHOD: This prospective, consecutive case series study was performed on 149 patients with ocular AHP at Farabi hospital, Iran, from February 2020 to June 2021. All patients underwent routine ophthalmic examinations. The manifestation of AHP was determined by direct observation from three viewing angles, while the patient read the smallest line on the vision chart that they could see. In front, above, and lateral gazes, observations were performed to find head tilt, head turn, and chin abnormal position, respectively. A picture with habitual AHP was taken from all patients. The amount of head tilt was measured by calculating the angle between the line that connects the lips center to the center of the eyebrows and the vertical line using the Corel Draw X7 computer software. RESULTS: The mean age of 149 patients with ocular AHP [101 (67.8%) males and 48 (32.2%) females] was 16.2 ± 12.2 (range, 2-57) years. The most common ocular sources of AHP were found to be superior oblique palsy (SOP) in 66 (44.3%) patients, 54 (36.2%) cases with Duane's retraction syndrome (DRS), and 12 (8.1%) patients with nystagmus. Other frequent causes of ocular AHP were dissociated vertical deviation (DVD) in 5 (3.4%), A and V pattern strabismus in 3 (2.0%), and 2 cases (1.3%) in each of Brown syndrome, inferior rectus (IR) palsy, and congenital fibrosis of the extraocular muscles (CFEOM). The most common manifestations of AHP in all cases were "pure head turn" (48.3%), followed by "pure head tilt" (24.8%), "simultaneous head tilt and head turn" (20.8%), and "chin up" (6.0%). The mean head tilt among all patients with head tilt was 10.4° ± 8.9° (range, 5.0°-31.7°). CONCLUSION: The most frequent ocular sources of AHP were SOP, DRS, and nystagmus, followed by DVD, A and V pattern strabismus, IR palsy, CFEOM, and Brown syndrome. In addition, pure head turn and pure head tilt were the most common manifestations of ocular AHP but were not always seen in the same direction or combination as previously reported with these etiologies.

Two novel CHN1 variants identified in Duane retraction syndrome pedigrees disrupt development of ocular motor nerves in zebrafish.

Duane retraction syndrome (DRS) is a rare congenital eye movement disorder causing by the dysplasia of abducens nerve, and has highly variable phenotype. MRI can reveal the endophenotype of DRS. Most DRS cases are sporadical and isolated, while some are familial or accompanied by other ocular disorders and systemic congenital abnormalities. CHN1 was the most common causative gene for familial DRS. Until now, 13 missense variants of CHN1 have been reported. In this study, we enrolled two unrelated pedigrees with DRS. Detailed clinical examinations, MRI, and the whole exome sequencing (WES) were performed to reveal their clinical and genetic characteristics. Patients from pedigree-1 presented with isolated DRS, and a novel heterozygous variant c.650 A > G, p. His217Arg was identified in CHN1 gene. Patients from pedigree-2 presented with classic DRS and abnormalities in auricle morphology, and the pedigree segregated another novel heterozygous CHN1 variant c.637 T > C, p. Phe213Leu. A variety of bioinformatics software predicted that the two variants had deleterious or disease-causing effects. After injecting of two mutant CHN1 mRNAs into zebrafish embryos, the dysplasia of ocular motor nerves (OMN) was observed. Our present findings expanded the phenotypic and genotypic spectrum of CHN1 related DRS, as well as provided new insights into the role of CHN1 in OMN development. Genetic testing is strongly recommended for patients with a DRS family history or accompanying systemic congenital abnormalities.

Magnetic Resonance Imaging Findings in Patients With Duane Retraction Syndrome.

BACKGROUND: Duane retraction syndrome (DRS) is known to relate to the absence of the abducens nucleus, with abnormal innervation of the lateral rectus (LR) muscle by branchesof the oculomotor nerve (CN III). The purposes of this study were to investigate the morphological characteristics of the oculomotor nerve (CN III), the abducens nerve (CN VI), and the extraocular muscles in patients with clinically diagnosed Duane retraction syndrome (DRS) using MRI. In addition, we assessed the association between ocular motility, horizontal rectus muscle volumes, and CN III/VI in patients with Duane retraction syndrome (DRS). METHODS: The study comprised 20 orthotropic control subjects (40 eyes) and 42 patients with Duane syndrome (48 eyes), including 20 patients with DRS Type I (24 eyes), 5 patients with DRS Type II (6 eyes), and 17 patients with DRS Type III (18 eyes). Three-dimensional (3D) T1/2 images of the brainstem and orbit were obtained to visualize the cranial nerves, especially the abducens (VI) and oculomotor (III) nerves, as well as extraocular muscles. RESULTS: Based on the clinical classification, among 42 patients, MRI showed that the abducens nerves (CN VI) on the affected side were absent in 24 of 24 eyes (100%; 20 patients) with Type I DRS and in 16 of 18 eyes (88%; 16 patients) with Type III DRS. However, CN VI was observed in 6 of 6 eyes (100%; 5 patients) with Type II DRS and in 2 of 18 eyes (11%) with Type III DRS. CN III was observed in all patients. The oculomotor nerves on the affected side were thicker than those on the nonaffected contralateral side in DRS Type I ( P < 0.05) and Type III ( P < 0.05), but not in DRS Type II. Smaller LR and larger MR volumes were shown in the affected eye than that in the nonaffected eye in DRS Types I and III. Based on the presence or absence of CN VI, there was a tendency for thicker oculomotor nerves in the affected eye than in the nonaffected eye in the absence groups ( P < 0.05). However, no significant difference was found in the present group. In the CN VI absence groups, similar results were found in the affected eyes than in the nonaffected eyes as in DRS Types I and III. In addition, the presence of CN VI was correlated with better abduction ( P = 0.008). The LR and MR volumes have positive correlations with the oculomotor nerve diameter in the affected eye. However, there was no correlation between the range of adduction/abduction and the LR/MR ratio in patients with or without an abducens nerve. CONCLUSIONS: Different types of DRS have different characteristic appearances of CN VI and CN III on MRI. Horizontal rectus muscles have morphological changes to adapt to dysinnervation of CN VI and aberrant innervation of CN III. Thus, these neuroimaging findings may provide a new diagnostic criterion for the classification of DRS, improving the comprehension of the physiopathogenics of this disease.

Síndrome de Duane: a propósito de un caso / Duane syndrome: a case report

El síndrome de Duane es una enfermedad poco frecuente en la cual se observa retracción del globo ocular y limitación de los movimientos horizontales. Presentamos el caso de un paciente de 11 años que acudió a Urgencias debido a una desviación ocular supuestamente de reciente instauración. En la exploración se objetiva un déficit en la abducción y la aducción, así como cierre de la fisura palpebral en la aducción forzada. Se diagnostica de síndrome de Duane tipo III y se decide manejo conservador con observación y seguimiento (AU)

Duane syndrome is a rare condition, whose clinical presentation involves retraction of the eyeball upon attempted abduction, and limitation of horizontal movements. We present the case of an 11-year-old patient who presented to the Emergency Department with a recent-onset ocular deviation. Examination revealed a deficit in abduction and adduction, as well as closure of the palpebral fissure in forced adduction. The patient was diagnosed with Duane syndrome type III, and conservative management with observation and follow up was decided. (AU)

[Novel frameshift mutations in SALL4 in two Chinese families with Okihiro syndrome].

In the present study, clinical manifestations of two Chinese Okihiro syndrome families were analyzed, and genetic detections were performed on the two probands by exome sequencing and verified by Sanger sequencing for family members to determine the biological pathogenesis. Prenatal diagnoses were provided for three high-risk fetuses. The affected members exhibited a wildly spectrum of phenotypes, including ultrasound abnormalities of skeletal system (radius deformity and abnormal posture), and cardiac system (persistent common arterial trunk and ventricular septal defect) in the prenatal period of family 1, the severe phenotypes (grossly shortened and deformed forearm, Duane's anomaly and hearing loss), and the mild ones (usually only thenar dysplasia, or short radius styloid process). Two SALL4 variants, c.844delC p.(Q282Kfs*8) and c.2210delG p.(G737Vfs*23), have been identified respectively in two probands, and c.2210delG of SALL4 gene was unreported previously. The two variants were verified in all affected individuals, not in normal family members. Genotyping results of three fetuses indicated that one fetus was normal, and the two fetuses with heterozygous variation were affected. The two variants of SALL4 gene, c.844delC p.(Q282Kfs*8) and c.2210delG p.(G737Vfs*23), were the molecular pathological cause of Okihiro syndrome in the present study and enriched the spectrum of SALL4 variants. Our study provides accurate prenatal genetic diagnosis for the two families to avoid the birth of affected children.

Síndrome de Wildervanck: reporte de un caso clínico / Wildervanck syndrome: clinical case report

El síndrome de Wildervanck (cérvico-óculo-acústico) es una patología muy rara, caracterizada por la tríada clásica de fusión de vértebras cervicales o anomalía de Klippel-Feil, síndrome de Duane (paresia del VI par craneal) e hipoacusia. Se han descrito, además, otras afecciones a nivel vascular, cardíaco y musculoesquelético. En este caso clínico, describimos a una paciente que cumple la tríada cardinal, además de presentar datos clínicos adicionales que no han sido reportados con anterioridad, lo cual contribuye a la ampliación del fenotipo de la enfermedad. Asimismo, realizamos una revisión de la literatura respecto a este síndrome

Wildervanck syndrome (also known as cervico-oculo-acoustic dysplasia) is a very rare disease, characterized by the typical triad of cervical vertebral fusion or Klippel-Feil anomaly, Duane syndrome (paresis of the sixth cranial nerve), and hearing loss. Other vascular, cardiac, and musculoskeletal conditions have also been described. In this case report, we describe a patient who met the cardinal triad and also presented additional clinical data that have not been previously reported, which contribute to broadening the disease phenotype. We have also reviewed the bibliography related to this syndrome.

Palpebral Fissure Changes in the Contralateral Eye in Duane Retraction Syndrome.

Duane retraction syndrome (DRS) is a congenital cranial dysinnervation disorder that is characterized by paradoxical lateral rectus muscle innervation of the affected eye by axons meant to innervate the ipsilateral medial rectus muscle, with resultant varying degrees of co-contraction. It is characterized by severe abduction deficiency, variable limitation of adduction, globe retraction with narrowing of the palpebral fissure, and oblique elevation or depression on adduction. A total of 16 patients with unilateral DRS were identified. The mean age was 13 ± 8 years (range: 6 to 28 years). There were 5 males and 11 females. The cohort included 8 patients with DRS type I, 3 patients with DRS type II, 4 patients with DRS type III, and 1 patient with synergistic divergence (DRS type IV). The mean width of the palpebral fissure in primary gaze was 9.95 ± 0.25 mm, increased in abduction to 11.11 ± 1.16 mm, and changed on adduction to 10.03 ± 1.19 mm. The mean reduction in the size of the palpebral fissure on adduction was 11.7 ± 10.2% (range: 0 to 30%). The difference in the palpebral fissure width between adduction and abduction was statistically significant (P = .0018). Of the 16 patients, 8 (50%) showed narrowing of the palpebral fissure of the contralateral eye on adduction compared to abduction of more than 10%. In this case series of unilateral Duane retraction syndrome, there was a common association between widening of the palpebral fissure of the unaffected eye and adduction of the eyes with DRS in DRS types II, III, and IV and DRS type I with upshoot or downshoot. [J Pediatr Ophthalmol Strabismus. 2023;60(3):e22-e25.].

Modified Nishida's procedure for esotropia in Duane syndrome associated with Goldenhar syndrome.

Modified Nishida's procedure (no split, no tenotomy transposition) has been recently described as an effective surgery for monocular elevation deficiency and for traumatic rupture of the inferior rectus muscle. We report the modified Nishida's procedure combined with medial rectus muscle recession for the treatment of esotropia in unilateral Duane syndrome associated with Goldenhar syndrome. Following the surgery and over a 1-year follow-up period, the patient was orthophoric at distance and near, abduction improved, and the abnormal head position resolved.

Modified Nishida Procedure Combined with Lateral Rectus Disabling for Duane Retraction Syndrome.

Duane retraction syndrome (DRS) is a complex congenital cranial dysinnervation disorder. The choice of surgical procedure in esotropic-DRS depends upon several factors that include: the amount of esotropia in the primary position, the presence and severity of palpebral fissure narrowing, globe retraction, presence of medial rectus muscle (MR) contracture, the likelihood of improving abduction, age of the patient, and the presence of binocularity and stereopsis. In the presence of MR contracture, MR recession is performed either alone (unilaterally or bilaterally) or in conjunction with Y splitting plus recession of the lateral rectus muscle (LR) for reducing globe retraction. MR recession, with or without adjustable sutures, may be simultaneously combined with partial thickness vertical rectus muscle transposition (VRT) or with superior rectus muscle transposition (SRT). We describe a novel combination of surgical procedures in the management of esotropic-DRS in two patients. In our first patient, following an initial MR recession combined with LR disinsertion and periosteal fixation (LRDAPF), a modified Nishida procedure was performed. In our second patient following a prior simultaneous MR recession and LR Y splitting with recession, we combined periosteal fixation of the LR with a modified Nishida procedure of the vertical rectus muscles.

Is the Pupil Involved in Duane Syndrome? Static and Dynamic Pupillometry Characteristics.

Objectives: Duane syndrome (DS) is typically characterized by abduction and/or adduction deficiency accompanied by eyelid and ocular motility disturbances. Maldevelopment or absence of the sixth nerve has been shown to be the causative factor. The aim of the present study was to investigate static and dynamic pupillary characteristics in patients with DS and compare the results with those of healthy eyes. Materials and Methods: Patients with unilateral isolated DS and no history of ocular surgery were enrolled in the study. Healthy subjects with a best corrected visual acuity (BCVA) of 1.0 or higher were assigned to the control group. All subjects underwent complete ophthalmological examination and pupillometry measurements (MonPack One, Vision Monitor System, Metrovision, Perenchies, France) including static and dynamic pupil evaluation. Results: A total of 74 patients (22 with DS and 52 healthy subjects) were included in the study. The mean age of the DS patients and healthy subjects was 11.05±5.19 and 12.54±4.05 years, respectively (p=0.188). There was no difference in sex distribution (p=0.502). Mean BCVA differed significantly between eyes with DS and healthy eyes, and between healthy eyes and the fellow eyes of DS patients (p<0.05). No significant difference was found in any static or dynamic pupillometry parameters (p>0.05 for all). Conclusion: In the light of the results of the present study, the pupil seems to be not involved in DS. Larger studies including more patients with different types of DS in different age groups or comprising patients with non-isolated DS may reveal different findings.

A novel de novo nonsense mutation in SALL4 causing duane radial ray syndrome: a case report and expanding the phenotypic spectrum.

BACKGROUND: SALL4, a member of the SALL genes family, encodes a zinc-finger transcriptional factor that either activates or represses gene transcription depending on cell type during embryonic development. SALL4 mutations cause extremely variable conditions including Duane-radial ray (DRR), Okihiro, Holt-oram, Acro-renal ocular and IVIC syndromes, all with autosomal dominant inheritance pattern. However, all these syndromes with different terminologies are actually the same entity termed SALL4 related disorders. CASE PRESENTATION: Herein, we examine an Iranian patient suspected to DRR syndrome which has not been previously described in the population. Whole-exome sequencing (WES) was performed to examine pathogenic genes in the proband. Subsequently, Sanger sequencing was used to confirm the mutation found. To elucidate the effects of the identified mutation, clinical data of patient was collected. Morever, the possible impact of the mutation found on the corresponding protein was evaluated using bioinformatics tools. WES identifed a novel de novo heterozygous nonsense mutation in exon 2 of SALL4 gene (c.712 C > T:p.Q238X). Subsequently, segregation and phenotype-genotype correlation analysis as well as in-silico approaches confirmed the autosomal dominance inheritance and disease-causing nature of the identified mutation. In addition, studied patient had features not described previously, including kyphoscoliosis, dimple presacral sinus, barrel chest and artric disc (C6-C7). These manifestations could be additional characteristics of the growing phenotypic spectrum of SALL4 related disorders. CONCLUSION: Our findings could extend the pathogenic mutations and phenotypic spectrum of SALL4 related disorders. Such reports can also aid to conduct genetic counseling, prenatal diagnosis and clinical management for individuals at high risk of SALL4 related disorders.

Orbital leiomyoma presenting as inverse globe retraction syndrome: a unique presentation of a rare disease.

Inverse globe retraction syndrome is a rare ocular motility disorder characterized by limited abduction, with globe retraction and up- or downshoots on attempted abduction, differentiating it from globe retraction due to Duane retraction syndrome, seen on attempted adduction. It can be congenital or acquired. We report the case of a 3-year-old girl who presented with classical features of inverse globe retraction syndrome secondary to an underlying orbital tumor involving the medial rectus muscle. Incisional biopsy confirmed the diagnosis of a leiomyoma. At 10 months' follow-up, vision, ocular alignment, and ocular motility had improved.

Structure of SALL4 zinc finger domain reveals link between AT-rich DNA binding and Okihiro syndrome.

Spalt-like 4 (SALL4) maintains vertebrate embryonic stem cell identity and is required for the development of multiple organs, including limbs. Mutations in SALL4 are associated with Okihiro syndrome, and SALL4 is also a known target of thalidomide. SALL4 protein has a distinct preference for AT-rich sequences, recognised by a pair of zinc fingers at the C-terminus. However, unlike many characterised zinc finger proteins, SALL4 shows flexible recognition with many different combinations of AT-rich sequences being targeted. SALL4 interacts with the NuRD corepressor complex which potentially mediates repression of AT-rich genes. We present a crystal structure of SALL4 C-terminal zinc fingers with an AT-rich DNA sequence, which shows that SALL4 uses small hydrophobic and polar side chains to provide flexible recognition in the major groove. Missense mutations reported in patients that lie within the C-terminal zinc fingers reduced overall binding to DNA but not the preference for AT-rich sequences. Furthermore, these mutations altered association of SALL4 with AT-rich genomic sites, providing evidence that these mutations are likely pathogenic.

Duane Retraction Syndrome: The Role of Botulinum Toxin A Injection in Adults and Its Impact on Quality of Life in an Indian Population.

PURPOSE: To evaluate the role of botulinum toxin A in the treatment of adults with Duane retraction syndrome and its impact on quality of life. METHODS: A total of 25 adults with unilateral Duane retraction syndrome were selected for this interventional case series. Botulinum toxin was injected in the appropriate horizontal recti. The parameters assessed were ocular deviation (▵), overshoots, and abnormal head posture. Patients were followed up at 1 day, 10 days, and 3 months after the injection. The outcome was categorized on the basis of deviation/abnormal head posture/overshoots as: (1) significant improvement (< 8 prism diopters [PD]/< 5 degrees/≤ grade 1); (2) partial improvement (8 to 20 PD/5 to 15 degrees/≤ grade 2); and (3) no improvement (> 20 PD/> 15 degrees/≥ grade 3). Patients with partial/significant improvement were considered to have a favorable outcome. The impact on quality of life was assessed using the Adult Strabismus-20 Questionnaire scores 10 days after injection. RESULTS: There was a significant reduction in ocular deviation in esotropic and exotropic Duane retraction syndrome at 10 days (P = .001) and 3 months (P = .04) after botulinum toxin injection. The abnormal head posture improved from 11.58 ± 7.43 to 7.86 ± 6.25 degrees at 10 days. Botulinum toxin had a positive impact on the Adult Strabismus-20 Questionnaire scores, which significantly improved (P < .05) at 10 days. A favorable outcome was noted in 21 patients at 10 days but only 4 patients at 3 months. Three patients developed ptosis and 1 patient with orthotropic Duane retraction syndrome developed transient exotropia. CONCLUSIONS: In adults with Duane retraction syndrome, botulinum toxin can have a useful diagnostic role by providing insight to patients and setting realistic expectations. It can identify patients likely to benefit from further treatment and also has a positive impact on quality of life. [J Pediatr Ophthalmol Strabismus. 2023;60(1):46-51.].

Concomitant Unilateral Duane Retraction Syndrome and Contralateral Brown's Syndrome.

A 10-year-old boy was introduced with a chief complaint of ocular misalignment from birth. Ocular examination indicated right Brown and left Duane retraction syndrome in a non-familial pattern. We suspect that a teratogenic damage or genetic mutation may be responsible for this combination.

Wildervanck syndrome: clinical case report. / Síndrome de Wildervanck: reporte de un caso clínico.

Wildervanck syndrome (also known as cervico-oculo-acoustic dysplasia) is a very rare disease, characterized by the typical triad of cervical vertebral fusion or Klippel-Feil anomaly, Duane syndrome (paresis of the sixth cranial nerve), and hearing loss. Other vascular, cardiac, and musculoskeletal conditions have also been described. In this case report, we describe a patient who met the cardinal triad and also presented additional clinical data that have not been previously reported, which contribute to broadening the disease phenotype. We have also reviewed the bibliography related to this syndrome.

El síndrome de Wildervanck (cérvico-óculo-acústico) es una patología muy rara, caracterizada por la tríada clásica de fusión de vértebras cervicales o anomalía de Klippel-Feil, síndrome de Duane (paresia del VI par craneal) e hipoacusia. Se han descrito, además, otras afecciones a nivel vascular, cardíaco y musculoesquelético. En este caso clínico, describimos a una paciente que cumple la tríada cardinal, además de presentar datos clínicos adicionales que no han sido reportados con anterioridad, lo cual contribuye a la ampliación del fenotipo de la enfermedad. Asimismo, realizamos una revisión de la literatura respecto a este síndrome.

Does head tilt influence facial appearance more than head turn?

Purpose: To evaluate the frequency of facial asymmetry parameters in patients with head tilt versus those with head turn. Methods: This cross-sectional comparative study was performed on 155 cases, including 58 patients with congenital pure head turn due to Duane retraction syndrome (DRS), 33 patients with congenital pure head tilt due to upshoot in adduction or DRS, and 64 orthotropic subjects as the control group. The facial appearance was evaluated by computerized analysis of digital photographs of patients' faces. Relative facial size (the ratio of the distance between the external canthus and the corner of the lips of both face sides) and facial angle (the angular difference between a line that connects two external canthi and another line that connects the two corners of the lips) measured as quantitative facial parameters. Qualitative parameters were evaluated by the presence of one-sided face, cheek, and nostril compression; and columella deviation. Results: The facial asymmetry frequency in patients with head tilt, head turn, and orthotropic subjects was observed in 32 (97%), 50 (86.2%), and 22 (34.3%), respectively (P < 0.001). In patients with head tilt and head turn, the mean facial angle was 1.78º ± 1.01º and 1.19º ± 0.84º, respectively (P = 0.004) and the mean relative facial size was 1.027 ± 0.018 and 1.018 ± 0.014, respectively (P = 0.018). The frequencies of one-sided nostril compression, cheek compression, face compression, and columella deviation in patients with pure head tilt were found in 19 (58%), 21 (64%), 19 (58%), and 19 (58%) patients, respectively, and in patients with pure head turn the frequencies were observed in 42 (72%), 37 (63%), 27 (47%), and 43 (74%), respectively. All quantitative and qualitative facial asymmetry parameters and facial asymmetry frequencies were significantly higher in head tilt and head turn patients as compared to the control group (P < 0.001). Conclusion: All facial asymmetry parameters in patients with head tilt and head turn were significantly higher than orthotropic subjects. The quantitative parameters such as relative facial size and facial angle were significantly higher in patients with pure head tilt than pure head turn. The results revealed that pure head tilt was associated with a higher prevalence of facial asymmetry than pure head turn.