Tony Pansell

Posterior canal dehiscence syndrome caused by an apex cholesteatoma.

Objective: To compare audio-vestibular findings caused by a dehiscence of the posterior semicircular canal with those found in the superior canal dehiscence syndrome. Study Design: Case report. Setting: University hospital, tertiary referral center. Patient: The 44-year-old woman suffered from a gradual hearing loss with pulse-synchronous tinnitus as well as sound and pressure-induced vertigo. Intervention: Audio-vestibular testing and high-resolution computed tomography. Main Outcome Measure: The superior canal dehiscence syndrome is caused by failure of normal postnatal bone development in the middle cranial fossa leading to absence of bone at the most superior part of the superior semicircular canal. The typical features for this syndrome are sound- and pressure-induced vertigo with torsional eye movements, pulse synchronous tinnitus and apparent conductive hearing loss in spite of normal middle-ear function. We present a patient with very similar symptoms and findings who, instead, had a posterior semicircular canal dehiscence caused by an apex cholesteatoma. Conclusion: Patients with semicircular canal dehiscence have common auditory-vestibular features regardless of which of the two vertical semicircular canals is affected. The only obvious difference between the two is the vertical component of the sound and pressure-induced eye movements (which beats in opposite directions).

Orthoptic findings and asthenopia in a population of Swedish schoolchildren aged 6 to 16 years.

Purpose: To determine the prevalence of refractive errors and binocular disorders in relation to asthenopia in a representative population of Swedish schoolchildren. Methods: The study population included 216 schoolchildren, 60 in grade 1 (age 6–7 years), 96 in grade 4 (10–12 years) and 60 in grade 8 (14–16 years). Asthenopia was evaluated by questionnaire. Visual acuity was tested for distance and near, uncorrected and with the best subjective refraction. Refraction in cycloplegia and an orthoptic assessment was performed. Results: Asthenopia was reported in 23.1% of schoolchildren; all but two of these schoolchildren had an abnormal eye examination. Asthenopia was related to uncorrected visual acuity ≤ 0.65 (13.9%*) and myopia (8.8%*). No significant correlation could be found to accommodative or convergence insufficiency. Conclusion: Asthenopia was significantly associated with uncorrected visual acuity ≤ 0.65 and with myopia (spherical equivalent −0.50 D or less) among Swedish schoolchildren.

Relative difference in orbital volume as an indication for surgical reconstruction in isolated orbital floor fractures.

In orbital floor fractures, the estimation of the herniated orbital content in the maxillary sinus has traditionally been the dividing line between surgical and nonsurgical management. In this study, we evaluated whether a relative change in volume would function as an indicator for surgical versus nonsurgical treatment of orbital floor fractures. This was a follow-up study in patients with untreated unilateral isolated orbital floor fractures admitted to our department from March 2003 to April 2007. Patients were contacted by regular mail and invited to have a clinical eye examination. The volume of the orbital content was calculated digitally from the patients’ computed tomography scans at the time of their injury. Eighteen subjects with no facial skeleton fracture were included for reference of orbital content volumes. Five of 23 patients showed 2 to 4 mm of enophthalmos, and only three of them had intermittent diplopia. No statistical correlation was found between the herniated volume and enophthalmos. No statistical correlation supporting the supposition that 1 mL of herniated orbital content would result in 1 mm of enophthalmos was found. The relative volume change between the fractured and nonfractured orbit in an individual does not appear to be a useful criterion for surgery. The importance of the herniated orbital tissue for the development of enophthalmos is unclear.

Accommodation Insufficiency in Children: Are Exercises Better than Reading Glasses?

Purpose: The aim of the present study was to investigate which mode of therapy, plus lens (+1.00D) reading addition (PLRA) or spherical flipper (± 1.50D), is the most effective in the treatment of accommodative insufficiency (AI). Methods: Initially, 24 subjects (mean age 10.3 years, ± 2.5 SD) with AI were included in the study. Ten subjects completed 8 weeks of PRLA treatment whereas 9, out of 14, subjects completed 8 weeks of spherical flipper treatment. Results: There was a statistically significant improvement in the accommodative amplitude with both regimes of treatment [F(1, 17) = 18.84, p = 0.0004). Spherical flipper treatment was found to have an overall larger effect on accommodative function as compared with PLRA treatment. However, accommodation did not reach normal values after only 8 weeks of treatment. Discussion: The results indicate that both methods improve the accommodative amplitude, but that overall accommodative function reaches higher levels of improvement with spherical flipper as compared with PLRA treatment. However, the accommodative function did not gain normal values in 8 weeks of treatment with either regime.

The influence of accommodative insufficiency on reading.

Background:  It is not known how accommodative insufficiency influences reading performance.

Drift in ocular torsion during sustained head tilt

Purpose: A head tilt towards the shoulder (roll) induces an ocular counter-roll (OCR), i.e. torsion in the opposite direction to the head. How this counter-rolled position is maintained during a static head tilt is in debate. In a previous study, we reported an OCR-increasing drift subsequent to the head tilt. This finding is in contrast to other reports where no such response was found. The primary aim of this study was to repeat the experiment during a prolonged head-tilt test and to describe the OCR characteristics. A secondary aim was to investigate the influence of spatial visual cues on OCR. Methods: Five male subjects performed a head tilt (30°) towards the right shoulder while the eye position was recorded during a 10-minute interval. In test 1, the subjects viewed a target with no cues for spatial orientation. The same head-tilt paradigm was repeated in test 2 with a visual target with spatial cues. Two samples of data were extracted from the start and the end of the recordings for statistical analysis. Results: Subsequent to the head tilt, a slow OCR-increasing drift in the opposite direction to the head roll was found in all subjects. On average, this drift lasted for 30 sec (± 5) in test 1 and for 55 sec (± 18) in test 2. The drift was then found to change its direction, i.e. the eyes were rotated in the same direction as the head roll. When measured after 10 minutes, the OCR was significantly decreased. Conclusions: The OCR during static head tilt is not constant. During the first minute there is a gradually increasing OCR. Thereafter, the amplitude of the OCR decreases gradually. These changes are influenced to some extent by spatial visual cues. Possible mechanisms are adaptive responses in otolithic afferents as well as central nervous memory functions related to the semicircular canal system.

Evaluation of Accommodative Insufficiency with the Visual Analogue Scale (VAS)

Purpose: The purpose of this study was to evaluate whether asthenopic symptoms in schoolchildren diagnosed with accommodative insufficiency (AI) and graded with the Visual Analogue Scale (VAS) could be correlated with the degree of accommodative deficiency in these children, and to investigate if VAS grading of the asthenopic symptoms could be used as an instrument to indicate the level of improvement of AI. Methods: Forty-nine children (mean age 10.2 years ± 2.7) diagnosed with AI graded their degree of asthenopia on the VAS before and after a 12-week treatment period wearing individually dispensed reading glasses. Results: The improvement in accommodation after treatment was statistically significant (p < 0.001) and 83.7% of the children obtained normal accommodative amplitude in relation to age. The reduction in asthenopic symptoms as graded with the VAS was also statistically significant (p < 0.001) after treatment and 89.9% of the children obtained a normal VAS score. However, no correlation between the degree of accommodative deficiency and the VAS grading could be found, neither before nor after treatment. Discussion: Based on these results we conclude that the visual analogue scale (VAS) cannot be used as an instrument to indicate the degree of accommodative deficiency nor can it be used to indicate the level of improvement during the course of treatment. However, the VAS can be used as an instrument to verify and document whether or not asthenopic symptoms are present, and therefore also to indicate when symptoms have been relieved.

Drift in Ocular Counterrolling during Static Head Tilt

Abstract: A decreasing drift of the counter‐rolled eye position (OCR) during head tilt was recently described. The underlying mechanism is not known. OCR in eleven healthy subjects was recorded (Search coil, Skalar) during a head tilt paradigm in two test conditions. The head was tilted with a velocity below (test 1) and above (test 2) detection threshold for the semicircular canals (SC) and held static for eight minutes. A significant drift of OCR was revealed in test 2 (P = .0006, ANOVA) and close to significant in test 1 (P = .07). No statistical difference was found between the two test conditions. The results suggest that the OCR drift was not caused by the SC complex merely.

Eye dominance in binocular viewing conditions.

Different degrees of eye dominance may need to be considered when comparing monocular and binocular performance or estimating binocular summation effects. The purpose of this study was to explore eye dominance under binocular viewing conditions and observe gradual differences in preference. Two binocular eye-dominance tests were evaluated and compared to the hole-in-the-card sighting test. The first experiment was based on a binocular sighting test. The second originated from the variable-angle mirror test, utilizing physiological diplopia to determine which eye dominates the binocular percept. The participants were 32 healthy subject with normal sight. For both experiments there were plausible effects of different degrees of eye dominance affecting how the subjects positioned or perceived the scene. The outcomes were supported by a statistically significant correlation with an interocular difference in sensitivity to degraded visibility. A statistically significant correlation was found between the hole-in-the-card test and the variable-angle mirror test (r = 0.527, p < 0.01). The experiments confirm the plausible occurrence of forms of eye dominance under binocular viewing conditions. The correlation with the hole-in-the-card test was weak to moderate, due to factors that appear to be related to testing and viewing conditions. Interocular differences in sensitivity to blur appear to be a useful factor in further grading of eye dominance.

Monocular and binocular reading performance in subjects with normal binocular vision

It is well known that problems with binocular vision can cause issues for reading; less known is to what extent binocular vision improves reading performance. The purpose of this study was to explore the role of binocularity by directly comparing monocular and binocular reading in subjects with typical reading skills and normal binocular vision. A secondary purpose was to assess any asymmetry in monocular performance and its association with the sighting dominant eye.