Anna Dickmann

Unilateral amblyopia: An optical coherence tomography study

PURPOSE To determine whether retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and foveal volume (FV) in patients with unilateral amblyopia differ between the amblyopic and the sound eye. METHODS A Humphrey-Zeiss Stratus (OCT3) with software 4.0.3.1 was used to evaluate 40 patients (17 male, 23 female; mean age, 15.2 years; range, 5-56 years) with unilateral amblyopia. Patients were divided into 2 groups: 20 strabismic and 20 anisometropic. Maps of macular thickness and RNFL thickness (3.46) created by the use of optical coherence tomography were applied to calculate FV and MT and RNFLT. RESULTS Mean best-corrected visual acuity was +0.3 LogMAR (range, +0.2 to +1.0) in the amblyopic eye. Mean RNFL thickness was not significantly different between eyes in either group. In strabismic amblyopia, mean MT and FV were 5% lower in the sound eye than in the amblyopic eye (MT, 267 microm vs 253 microm, p = 0.005; FV, 2.57 mm(3) vs 2.43 mm(3), p = 0.001). In anisometropic amblyopia, there was no significant difference between eyes in either MT or FV. CONCLUSIONS In patients with strabismic amblyopia, the MT and FV were slightly but significantly lower in the sound eye than in the amblyopic eye. The clinical importance of this difference is not known. No such difference was observed in patients with anisometropic amblyopia.

Convergent strabismus fixus in high myopic patients.

Patients with high myopia may develop a myopathy which frequently results in a sort of convergent strabismus fixus. Echographic and CT scan findings give evidence that a myopathic paralysis of the lateral rectus is supported by a slow pressure on this muscle squeezed between the lateral orbital wall and the enlarged eyeball.

A morpho-functional study of amblyopic eyes with the use of optical coherence tomography and microperimetry.

PURPOSE To determine whether retinal nerve fiber layer thickness (RNFLT), macular thickness, foveal volume, macular sensitivity, and fixation in patients with amblyopia differ between the amblyopic eye and the fellow eye. METHODS Optical coherence tomography (OCT) and microperimetry (MP-1) were used to evaluate patients with unilateral amblyopia. Patients were divided into 2 groups, those with strabismic amblyopia and those with refractive amblyopia. OCT maps were used to calculate foveal volume, macular thickness, and RNFLT; MP-1 was used to determine macular sensitivity and fixation. RESULTS A total of 30 patients were included (13 males; mean age 19.7 years [range, 10-38 years]), 15 in each group. Mean best-corrected visual acuity was 20/35 (range, 20/50 to 20/32) in the amblyopic eye and 20/21 (range, 20/20 to 20/25) in the fellow eye. In both groups, mean foveal volume and RNFLT did not differ significantly between eyes. Only macular thickness in the strabismic group differed significantly between the amblyopic and fellow eyes (P = 0.03). Macular sensitivity was significantly greater in the fellow eye in both groups (strabismic group, P = 0.002; refractive group, P = 0.013), whereas fixation did not change significantly between the amblyopic and fellow eye. RNFLT and macular sensitivity was found to be significantly correlated (strabismic group, r = 0.84, P = 0.002; refractive group, r = 0.66, P = 0.02). CONCLUSIONS Our data suggest that although RNFLT does not vary between eyes, macular sensitivity is reduced in patients with amblyopia.

Visual function in infants with non-syndromic craniosynostosis

The aim of this study was to assess various aspects of visual function in children with single‐suture, non‐syndromic craniosynostosis. Thirty‐eight infants (28 males, 10 females; age range 3.5–13mo, mean age 7mo, 11 with plagiocephaly, 12 with trigonocephaly, and 15 with scaphocephaly), were assessed with a battery of tests specifically designed to assess various aspects of visual function in infancy. Thirty‐two of the 38 infants had at least one abnormality on one of the aspects of visual function assessed. Abnormal eye movements were found in eight infants of the whole cohort and were mainly found in infants with plagiocephaly (6/11), who also had frequent visual field abnormalities (5/11). In contrast, fixation shift, an aspect of visual function related to the integrity of parietal lobes, was more frequently abnormal in patients with scaphocephaly. Our results suggest that the presence and severity of visual impairment is related to the type of craniosynostosis. Follow‐up studies after surgical correction are needed to evaluate the possible beneficial effects of reconstructive surgery on visual function.

A fast visual evoked potential method for functional assessment and follow-up of childhood optic gliomas

OBJECTIVE To evaluate a fast technique of visual evoked potentials (VEPs) recording, in response to steady-state luminance stimuli (SS-LVEPs), for functional assessment and follow-up of childhood optic gliomas (OGs). METHODS Eighteen OG patients (age range: 3.5-18 years), with different degrees of optic pathway damage severity, were examined. Sixteen age-matched normal subjects served as controls. Ten of the 18 OG patients were re-tested 1-3 months after the first examination. SS-LVEPs were elicited by a sinusoidally-modulated flickering (8 Hz) uniform field, generated by a light emitting diode (LED)-array and presented monocularly in a mini-ganzfeld. Amplitude and phase of the Fourier-analyzed response fundamental (1F) and second harmonic (2F) were measured. The full VEP protocol had a median duration of 6 min (range: 4-12). RESULTS When compared to normal control values, median 1F and 2F SS-LVEP amplitudes of OG patients were reduced (P<0.01), with a borderline increase in 2F phase lag (P<0.05). In 11 OG patients with asymmetric optic pathway damage in between-eye comparisons, median 1F amplitude losses were greater (P<0.01) in fellow eyes with more severe damage. No significant interocular difference was observed in control subjects. Median test-retest changes of 1F and 2F component were <20% and 30 degrees for amplitude and phase, respectively. In individual OG patients, 1F and 2F amplitudes were positively correlated (P<0.01) with visual acuity. 1F amplitude losses were correlated (P=0.01) with the severity of optic disc atrophy. Considering both 1F and 2F abnormalities, diagnostic sensitivity of SS-LVEP in detecting OG-induced optic pathways damage was 83.3%. CONCLUSIONS The present findings support the use of this technique, as an alternative to pattern VEPs, for functional assessment and follow-up of OG in uncooperative children.

Measurement of retinal nerve fiber layer thickness, macular thickness, and foveal volume in amblyopic eyes using spectral-domain optical coherence tomography

Although the changes in the anatomy of the visual cortex and lateral geniculate nucleus as the result of amblyopia have been well documented, retinal involvement is still controversial. Time-domain optical coherence tomography with an axial resolution of 10 μm has been used to evaluate retinal and peripapillary tissues in amblyopic eyes with contradictory results. Spectral domain optical coherence tomography has a greater resolution (5-10 μm) and can determine retinal layers more precisely. Our purpose was assess by means of spectral domain optical coherence tomography whether the retinal nerve fiber layer thickness, macular thickness, and foveal volume of the amblyopic and the fellow eyes differ in patients with unilateral amblyopia. Intereye differences in these parameters were found to be insignificant.

Longitudinal assessment of visual development in non-syndromic craniosynostosis: a 1-year pre- and post-surgical study.

Objective: to investigate visual function pre- and post surgery in children with single-suture non-syndromic craniosynostosis Design: Twenty-nine infants (12 with sagittal synostosis, 10 with trigonocephaly and 7 with anterior plagiocephaly) were longitudinally evaluated using a battery of tests assessing various aspects of visual function, including ocular behaviour, acuity, visual fields and fixation shift. All infants were assessed before surgery and 2, 6 and 12 months after surgery. Results: Before surgery only 16% of infants had completely normal visual function, while on the assessment performed 12 months after surgery, the number with normal results on all the tests increased to 65%. The only abnormalities found 12 months after surgical correction were mainly found on abnormal oculomotor behaviour in infants with plagiocephaly. Conclusion: Abnormalities of visual function were not frequent in infants with non-syndromic craniosynostosis who underwent surgical correction. Approximately half of the patients had some visual abnormalities before surgery, which subsequently improved, showing a delayed visual maturation rather than persistent abnormalities.

Functional Loss of the Inner Retina in Childhood Optic Gliomas Detected by Photopic Negative Response

PURPOSE To determine whether the Ganzfeld ERG photopic negative response (PhNR), an assay of inner retinal activity, is altered in childhood optic glioma (OPG). METHODS Seventeen pediatric patients with a diagnosis of OPG, established on neuro-ophthalmologic and brain/orbit magnetic resonance imaging (MRI) criteria, were enrolled. The examination protocol included determination of visual acuity (VA), fundus examination, retinal nerve fiber layer (RNFL) measurement with spectral-domain optical coherence tomography (SD-OCT) and photopic ERG. Fifteen normal children served as control group. Ten of the 17 OPG patients were retested 1 to 3 months after the first examination. Photopic ERGs were recorded after 10 minutes of light adaptation in response to a Ganzfeld flash presented on a steady light-adapting background. Amplitude and peak-time of b-wave and PhNR were measured. RESULTS Compared with normal values, PhNR amplitude was significantly reduced (P < 0.0001) in the OPG group. Peak-time of PhNR as well as b-wave amplitude and peak-time were similar in both patients and controls. Losses of PhNR were found in patients with involvement of either anterior or retro-chiasmatic optic pathways. Linear regression analysis showed significant positive correlation between RNFL thickness and PhNR amplitude (r2 = 0.34, P = 0.008). Mean percentage test-retest difference for PhNR amplitude and peak-time was 12% and 6%, respectively. CONCLUSIONS These findings indicate that flash ERG PhNR can detect a loss of inner retinal function in childhood OPGs supporting the use of this technique, as an adjunct to standard psychophysical and electrophysiological tests, to monitor visual function in OPG.

Ocular manifestations in Wolf-Hirschhorn syndrome

INTRODUCTION Wolf-Hirschhorn syndrome (WHS) multiple congenital anomalies/mental retardation is caused by partial deletion of the short arm of chromosome 4 and can be considered a contiguous gene syndrome, characterized by typical facial appearance, mental retardation, growth delay, and seizures. METHODS We investigated the ocular defects in a population of 10 patients with WHS and analyzed the relationship between ocular findings and the extent of deletion on chromosome 4. RESULTS The ocular abnormalities found included hypertelorism, strabismus, refractive errors, epicanthal folds, proptosis, downslanting palpebral fissures, microphthalmos, microcornea, iris coloboma, optic nerve coloboma, ocular cyst, ptosis, glaucoma, and nystagmus. Different breakpoints of the chromosomal rearrangement were observed in individual patients, ranging from 4p15.1 to 4p16.3, and the size of chromosomal deletion ranged from 2.6 to 26 million base pairs. CONCLUSIONS Congenital glaucoma and colobomatous ocular cysts have rarely been described in WHS patients that were previously reported. In all cases exhibiting strabismus, an exodeviation was present. Comparing genotype with ocular phenotype, a relationship between the size of deletion and the severity of the ocular involvement was observed in all cases but one.

Identification of the preferential gaze position through evaluation of visual fatigue in a selected group of VDU operators

A selected group of VDU workers were tested in an attempt to achieve objective evidence of visual fatigue and to identify a preferential monitor/gaze position during a particular work setting. Each subject was scored in a two-phase test. The highest mean scores were achieved when the monitor was lowered with respect to the primary/gaze position; the scores obtained with the monitor in primary or upward gaze position were significantly lower (p<0.001). The downward gaze position should be considered more comfortable for both innervational and anatomical factors, as stated in previous studies of ocular mobility. A reduction of vertical saccades could also play a role in lessening visual fatigue in this gaze position.