RESUMEN
There are three keys to understanding how the new way of classifying and treating intermittent exotropia (IXT) differs from Burian's classic classification. First, the assumption that lateral rectus surgery selectively affects the distance deviation, recess/resect procedures affect the distance and near equally, and that medial rectus surgery selectively affects the near deviation, are false assumptions. Second, AC/A ratios in IXT can be calculated in all the usual manners, provided that any near measurement used in the calculation be made after prolonged monocular occlusion to eliminate the contaminating effect of the Scobee phenomenon. Third, the use of +3 diopter (D) lenses at near and prolonged monocular occlusion are not interchangeable and work on different mechanisms, the former on accommodative convergence and the latter on fusional convergence. All patients with IXT should have a measurement taken after prolonged monocular occlusion, as well as while fixating on a far distant outdoor target prior to surgery, which should target the largest angle measured.
Asunto(s)
Exotropía , Cristalino , Acomodación Ocular , Enfermedad Crónica , Exotropía/cirugía , Humanos , Músculos Oculomotores/cirugíaRESUMEN
PURPOSE: To compare the characteristics and surgical outcomes in patients with tenacious proximal fusion (TPF) and high accommodative convergence/accommodation ratio (AC/A) types of intermittent exotropia. METHODS: This study retrospectively enrolled 40 patients with intermittent exotropia, 23 with TPF and 17 with high AC/A. Binocular function was evaluated by Worth's 4-dot test. Patients underwent lateral rectus recession, and surgical outcomes were compared. Surgical success was defined as less than ±10 prism diopters (PD) at 12 months postoperatively. RESULTS: The proportion of diplopia at near, evaluated by Worth's 4-dot test, was significantly higher in patients with high AC/A than in those with TPF (35.3% vs. 4.3%, p = 0.029). The mean preoperative angles of deviation in TPF and high AC/A types were 28.3 ± 4.4 and 28.8 ± 4.5 PD at distances, and 14.7 ± 4.2 and 15.1 ± 4.1 PD at near. Twelve months after surgery, the mean angles of deviation in TPF and high AC/A types were 2.9 ± 9.8 and 1.2 ± 9.6 PD, respectively, at distance and 1.7 ± 7.7 and -1.3 ± 11.3 PD at near. The surgical success rates were similar in the TPF and high AC/A types (74.0% vs. 64.7%). Five (21.7%) patients with TPF and 2 (11.8%) with high AC/A type experienced recurrence, with consecutive esotropia occurring in 1 (4.3%) patient with TPF and 4 (23.5%) patients with high AC/A. CONCLUSIONS: The proportion of diplopia at near was higher in patients with high AC/A type than in those with TPF intermittent exotropia. However, the surgical success rates were not significantly different between the types.
Asunto(s)
Acomodación Ocular/fisiología , Convergencia Ocular/fisiología , Exotropía/cirugía , Músculos Oculomotores/cirugía , Procedimientos Quirúrgicos Oftalmológicos , Visión Binocular/fisiología , Niño , Preescolar , Diplopía/fisiopatología , Exotropía/fisiopatología , Femenino , Humanos , Masculino , Músculos Oculomotores/fisiopatología , Estudios Retrospectivos , Resultado del Tratamiento , Agudeza Visual/fisiologíaRESUMEN
PURPOSE: To compare the characteristics and surgical outcomes in patients with tenacious proximal fusion (TPF) and high accommodative convergence/accommodation ratio (AC/A) types of intermittent exotropia. METHODS: This study retrospectively enrolled 40 patients with intermittent exotropia, 23 with TPF and 17 with high AC/A. Binocular function was evaluated by Worth's 4-dot test. Patients underwent lateral rectus recession, and surgical outcomes were compared. Surgical success was defined as less than ±10 prism diopters (PD) at 12 months postoperatively. RESULTS: The proportion of diplopia at near, evaluated by Worth's 4-dot test, was significantly higher in patients with high AC/A than in those with TPF (35.3% vs. 4.3%, p = 0.029). The mean preoperative angles of deviation in TPF and high AC/A types were 28.3 ± 4.4 and 28.8 ± 4.5 PD at distances, and 14.7 ± 4.2 and 15.1 ± 4.1 PD at near. Twelve months after surgery, the mean angles of deviation in TPF and high AC/A types were 2.9 ± 9.8 and 1.2 ± 9.6 PD, respectively, at distance and 1.7 ± 7.7 and −1.3 ± 11.3 PD at near. The surgical success rates were similar in the TPF and high AC/A types (74.0% vs. 64.7%). Five (21.7%) patients with TPF and 2 (11.8%) with high AC/A type experienced recurrence, with consecutive esotropia occurring in 1 (4.3%) patient with TPF and 4 (23.5%) patients with high AC/A. CONCLUSIONS: The proportion of diplopia at near was higher in patients with high AC/A type than in those with TPF intermittent exotropia. However, the surgical success rates were not significantly different between the types.
Asunto(s)
Humanos , Diplopía , Esotropía , Exotropía , Recurrencia , Estudios Retrospectivos , TelescopiosRESUMEN
BACKGROUND AND PURPOSE: When patients with intermittent exotropia show an increase in their near deviation after prolonged monocular occlusion, they have been said to have tenacious proximal fusion (TPF). That term is not adequately descriptive, since this finding can occur without the patient having been allowed to fuse. The purpose of this study is to investigate the possibility that this phenomenon is mediated by the preponderance of binasal retinal disparity and uncrossed localization that occurs with near fixation. PATIENTS AND METHODS: Ten patients with intermittent exotropia who manifested TPF were measured at 6 m, 1/3 m, again at 1/3 m after 1 hour of monocular occlusion, and at 1/3 m with a peripheral crossed localization stimulating device (PCLSD) that simulated the retinal bitemporal disparity and peripheral crossed localization usually found with distance fixation. RESULTS: For the ten patients, the mean measurement at distance was 28.3Δ±3.1, initially at near was 4Δ±3.9, at near after prolonged monocular occlusion was 25.3Δ±5.3, and at near with the PCLSD was 18.5Δ±4.1. The differences between the initial near measurement and the measurement with the PCLSD, and between the PCLSD and post-prolonged monocular occlusion were significant with P<0.001 and P=0.0049, respectively. CONCLUSIONS: What has been previously referred to as TPF in fact appears to be convergence induced by the preponderance of binasal retinal disparity and/or peripheral uncrossed localization typically found with near fixation. For simplicity, I propose the term TPF should be replaced with the "Scobee Phenomenon."
Asunto(s)
Acomodación Ocular , Convergencia Ocular/fisiología , Exotropía/fisiopatología , Niño , Exotropía/diagnóstico , Femenino , Fijación Ocular/fisiología , Humanos , Masculino , Estudios Prospectivos , Privación SensorialRESUMEN
PURPOSE: In order to evaluate the incidence and clinical characteristics of exodeviation according to the Kushner's classification. METHODS: We prospectively studied the 820 patients with exodeviation from 1998 to 2003. One hundred thirty patients with systemic abnormalities, eye disease except exodeviation, or histories of previous strabismus operations were excluded. Best-corrected visual acuity, alternate prism cover test or Krimsky test, duction/ versions, funduscopy, and cycloplegic refraction were performed in every patient, and Bielschowsky phenomenon, Worth 4 dot test and Titmus stereotest, in possible patients. We categorized exodeviations according to the Kushner's classification. RESULTS: Of the remaining 690 patients with exodeviation, 318 were male and 372 were female. Age of onset of exodeviation was 3.9 years. Basic exodeviation was most common (76.5%), and followed by tenacious proximal fusion (7.1%), convergence insufficiency (2.8%), proximal convergence (0.6%), pseudo-convergence insufficiency (0.6%) and high AC/A ratio (0.4%). Binocular fusion both at near and at distance was observed in 30% (148 patients) of the patients. The incidence of amblyopia and dissociated vertical deviation was 13.9% and 8.5%, respectively. Bielschowsky phenomenon was observed mostly in patients with early-onset exodeviation. CONCLUSIONS: Basic exodeviation was most commonly observed, followed by tenacious proximal fusion and convergence insufficiency. Patients with exodeviation showed an onset age of 3.9 years and accompanied by an amblyopia and dissociated vertical deviation in 14% and 5%, respectively. One third of the patients showed binocular fusion.