Jan-Roelof Polling

Electronically measured compliance with occlusion therapy for amblyopia is related to visual acuity increase

Abstract Purpose. We set out to determine whether the children who have low compliance (measured electronically) with occlusion therapy for amblyopia are those with insufficient increase of visual acuity. Methods. In 14 newly identified amblyopic children (mean age 4.3±1.9 years), compliance was measured electronically over a period of 1 week, 6 months after the start of occlusion therapy. Compliance was measured with an Occlusion Dose Monitor (ODM). The measurements took place during planned domiciliary visits. The children were diagnosed with anisometropia (n=5), strabismus (n=4) and anisometropia and strabismus (n=5). Compliance was expressed in percentages of the electronically registered time compared with the prescribed occlusion time. Satisfactory acuity increase following 6 months of occlusion therapy was defined on reaching any of the following criteria: acuity increase expressed as a ratio between acuity of the amblyopic eye and acuity of the good eye of more than 0.75, acuity of the amblyopic eye exceeding 0.5 as measured on the E-Chart or Landolt-C, or three LogMAR lines of increase in acuity. Results. Measured compliance averaged 80% in the eight children who had a satisfactory acuity increase and 34% in the six children who had an unsatisfactory visual acuity increase. Children with low acuity increase had statistically significantly lower compliance (P=0.038). Conclusion. The general assumption among orthoptists, that compliance with occlusion therapy for amblyopia is low in children with insufficient acuity increase, has been validated by electronic, objective means.

Prevalence of amblyopia and refractive errors in an unscreened population of children.

Purpose To describe the frequency of refractive errors and amblyopia in unscreened children aged 2 months to 12 years from a rural town in Poland. Methods Five hundred ninety-one children were identified by medical records and examined in a standardized manner. Visual acuity was measured using LogMAR charts; refractive error was determined using retinoscopy or autorefraction after cycloplegia. Myopia was defined as spherical equivalent (SE) ⩽−0.50 D, emmetropia as SE between −0.5 D and +0.5 D, mild hyperopia as SE between +0.5 D and +2.0 D, and high hyperopia as SE ≥+2.0 D. Amblyopia was classified as best-corrected visual acuity ≥0.3 (⩽20/40) LogMAR, in combination with a 2 LogMAR line difference between the two eyes and the presence of an amblyogenic factor. Results Refractive errors ranged from 84.2% in children aged up to 2 years to 75.5% in those aged 10 to 12 years. Refractive error showed a myopic shift with age; myopia prevalence increased from 2.2% in those aged 6 to 7 years to 6.3% in those aged 10 to 12 years. Of the examined children, 77 (16.3%) had refractive errors, with visual loss; of these, 60 (78%) did not use corrections. The prevalence of amblyopia was 3.1%, and refractive error attributed to the amblyopia in 9 of 13 (69%) children. Conclusions Refractive errors are common in Caucasian children and often remain undiagnosed. The prevalence of amblyopia was three times higher in this unscreened population compared with screened populations. Greater awareness of these common treatable visual conditions in children is warranted.

Vertical position of the orbits in nonsyndromic plagiocephaly in childhood and its relation to vertical strabismus

Purpose:To determine the existence of a correlation between the vertical angle of strabismus and the vertical angle between the orbital axes in nonsyndromic plagiocephaly in childhood. Methods:Patients were included when diagnosed with plagiocephaly. Orthoptic measurements showed a vertical strabismus and three-dimensional computed tomographic (CT) imaging of the skull was available. Patients were excluded if plagiocephaly was part of a syndrome or if any surgical intervention had taken place before our measurements. Three-dimensional CT imaging was used to calculate the vertical angle between the orbital axes in 3 reference planes (VAO) perpendicular to a line of reference through the lower borders of the maxilla (VAOmax), both auditory canals (VAOaud), and the lower points of the external occipital protuberances (VAOocc). Results:Fourteen patients were included (mean age, 14 mo). Three-dimensional CT measurements showed a mean (SD) VAOmax of 1.70 (2.31) degrees, VAOaud of −1.54 (1.46) degrees, and VAOocc of −2.06 (4.29) degrees (a negative value indicates that the eye on the affected side was situated lower in the head). The mean vertical angle of strabismus was −2.39 (4.69) degrees in gaze toward the affected side, 3.66 (3.77) degrees in gaze ahead, and 8.14 (5.63) degrees in gaze toward the nonaffected side. The Pearson test showed no significant correlations. Conclusions:The clinical observation that vertical strabismus in adult plagiocephaly is correlated with the vertical angle of the orbital axes could not be confirmed in young children.