A Consensus Statement on the Terminology for Automated Visual Field Abnormalities.

BACKGROUND: A multitude of terms have been used to describe automated visual field abnormalities. To date, there is no universally accepted system of definitions or guidelines. Variability among clinicians creates the risk of miscommunication and the compromise of patient care. The purposes of this study were to 1) assess the degree of consistency among a group of neuro-ophthalmologists in the description of visual field abnormalities and 2) to create a consensus statement with standardized terminology and definitions. METHODS: In phase one of the study, all neuro-ophthalmologists in Israel were asked to complete a survey in which they described the abnormalities in 10 selected automated visual field tests. In phase 2 of the study, the authors created a national consensus statement on the terminology and definitions for visual field abnormalities using a modified Delphi method. In phase 3, the neuro-ophthalmologists were asked to repeat the initial survey of the 10 visual fields using the consensus statement to formulate their answers. RESULTS: Twenty-six neuro-ophthalmologists participated in the initial survey. On average, there were 7.5 unique descriptions for each of the visual fields (SD 3.17), a description of only the location in 24.6% (SD 0.19), and an undecided response in 6.15% (SD 4.13). Twenty-two neuro-ophthalmologists participated in the creation of a consensus statement which included 24 types of abnormalities with specific definitions. Twenty-three neuro-ophthalmologists repeated the survey using the consensus statement. On average, in the repeated survey, there were 5.9 unique descriptions for each of the visual fields (SD 1.79), a description of only the location in 0.004% (SD 0.01), and an undecided response in 3.07% (SD 2.11%). Relative to the first survey, there was a significant improvement in the use of specific and decisive terminology. CONCLUSIONS: The study confirmed a great degree of variability in the use of terminology to describe automated visual field abnormalities. The creation of a consensus statement was associated with improved use of specific terminology. Future efforts may be warranted to further standardize terminology and definitions.

Isolated foveal hypoplasia with secondary nystagmus and low vision is associated with a homozygous SLC38A8 mutation.

Foveal hypoplasia, always accompanied by nystagmus, is found as part of the clinical spectrum of various eye disorders such as aniridia, albinism and achromatopsia. However, the molecular basis of isolated autosomal recessive foveal hypoplasia is yet unknown. Individuals of apparently unrelated non consanguineous Israeli families of Jewish Indian (Mumbai) ancestry presented with isolated foveal hypoplasia associated with congenital nystagmus and reduced visual acuity. Genome-wide homozygosity mapping followed by fine mapping defined a 830 Kb disease-associated locus (LOD score 3.5). Whole-exome sequencing identified a single missense mutation in the homozygosity region: c.95T>G, p.(Ile32Ser), in a conserved amino acid within the first predicted transmembrane domain of SLC38A8. The mutation fully segregated with the disease-associated phenotype, demonstrating an ∼10% carrier rate in Mumbai Jews. SLC38A8 encodes a putative sodium-dependent amino-acid/proton antiporter, which we showed to be expressed solely in the eye. Thus, a homozygous SLC38A8 mutation likely underlies isolated foveal hypoplasia.

Utility in clinical practice of standard vs. high-intensity ERG a-waves.

PURPOSE: Standard ERG a-waves represent contributions from both photoreceptor and inner retinal cells, while the leading edge of the high-intensity a-wave is produced only by photoreceptors. This has raised questions about the value of the a-wave as an indicator of photoreceptor disease, and has led to suggestions for standardizing higher-intensity stimuli. Our objective was to compare the behavior of standard and high-intensity a-waves in clinical practice. METHODS: Standard ISCEV (International Society for Clinical Electrophysiology of Vision) a-waves and high-intensity a-wave responses were recorded under scotopic and photopic conditions from normal subjects and from patients with photoreceptor dystrophies and other diseases. RESULTS: The standard scotopic a-wave amplitude followed the high-intensity a-wave closely among patients with different diagnoses, and the results did not change significantly when cone a-waves were subtracted to isolate rod signals. The only exception was one patient with the enhanced S cone syndrome (ESCS) whose dark-adapted responses were cone-driven. Initial peak times clustered in a small range for both standard and high-intensity responses, and were not very sensitive to disease. CONCLUSION: High-intensity a-waves can show photoreceptor characteristics directly, and may help analyze some rare disorders. However, in our study the amplitude of conventional scotopic a-waves mirrored that of the high-intensity responses quite closely over a wide range of patients. This suggests that for practical purposes even if it is not perfect, the standard ERG is an excellent indicator of photoreceptor disease.

Endoscopic orbital decompression for Graves' ophthalmopathy.

BACKGROUND: In patients with Graves' ophthalmopathy, orbital decompression surgery is indicated for compressive optic neuropathy, severe corneal exposure, or for cosmetic deformity due to proptosis. Traditionally this has been performed through a transantral approach, but the associated complication rate is high. More recently, endoscopic orbital decompression has been performed successfully with significantly fewer postoperative complications. OBJECTIVE: To report our experience of endoscopic orbital decompression in patients with severe Graves' ophthalmopathy. METHODS: Three patients (five eyes) underwent endoscopic orbital decompression for Graves' ophthalmopathy at Soroka Medical Center between the years 2000 and 2002. The indications for surgery were compressive optic neuropathy in three eyes, severe corneal exposure in one eye, and severe proptosis not cosmetically acceptable for the patient in one case. An intranasal endoscopic approach with the removal of the medial orbital wall and medial part of the floor was performed. RESULTS: In all five eyes an average reduction of 5 mm in proptosis was achieved. Soon after surgery, visual acuity improved in the three cases with compressive optic neuropathy, and exposure keratopathy and cosmetic appearance also improved. The diplopia remained unchanged. No complications were observed postoperatively. CONCLUSIONS: Endoscopic orbital decompression with removal of the medial orbital wall and medial part of the floor in the five reported eyes was an effective and safe procedure for treatment of severe Graves' ophthalmopathy. A close collaboration between ophthalmologists and otorhinolaryngologists skilled in endoscopic sinus surgery is crucial for the correct management of these patients.

Are circadian variations in the electroretinogram evident on routine testing?

We sought to determine whether routine ERGs using ISCEV standard stimuli, would show a pattern of circadian variation. We examined ERGs from 40 successive normal subjects who were tested at different times during regular laboratory operating hours of 9 am to 4 pm, and also reviewed high intensity a-waves from a subgroup. There were no obvious associations of either ERG amplitude or implicit time with time of day. No statistically significant difference was found between average ISCEV ERG parameters or high-intensity a-wave parameters obtained in the morning (9 am to 1 pm) and afternoon (1 pm to 4 pm). We conclude that time of day is not critical for routine ERG recordings, although small, variable, circadian changes may well be present. We suggest that the time of day be noted on clinical recordings, in case this information becomes relevant for a particular patient.

Clinical S-cone ERG recording with a commercial hand-held full-field stimulator.

Our purpose was to explore S-cone ERG protocols for a commercial full-field hand-held stimulator that contains colored LEDs, and to see whether the test would be useful as a part of routine ERG testing. S-cone responses were elicited by blue flashes over a longer-wavelength background. With the standard stimulator containing blue (461 nm), green (513 nm) and red (652 nm) LEDs, we were unable to obtain satisfactory responses. Reproducible S-cone ERGs were obtained with a stimulator that had been custom-fitted with shorter-wavelength blue (440 nm) LEDs for stimulation, and orange (590 nm) LEDs for background adaptation. S-cone responses took only a few minutes to record, and the typical waveform showed a slow peak at 45-50 ms with amplitude 3-9 microV, but ranging from 0 microV to more than 10 microV. Larger waves appeared in a patient with enhanced S-cone syndrome. S-cone responses could also be obtained with an alternating blue-orange flicker protocol. We added the S-cone response to our regular ERG protocol for a number of months. Although most normal subjects and patients showed recognizable S-cone responses with this stimulator, the amplitudes were small and there was too much variability to make the technique effective for routine clinical testing. In general, the S-cone responses followed the standard cone ERG responses in disease.

Attempted bilateral manual enucleation (gouging) during a physical assault.

OBJECTIVE: To report a rare, severe case of partial traumatic bilateral enucleation and its assessment and management. DESIGN: Case report and literature review. METHODS: A report of clinical and imaging findings, surgical procedure, medical treatment, and final outcome. RESULTS: Complete avulsion of the extraocular muscles and optic nerve resulted in total loss of vision in one eye. Partial visual recovery was achieved by operating on the fellow eye, which was partially avulsed. Both eyes underwent lateral canthotomy in the emergency room. This was followed by exploration, repair of all ruptured extraocular muscles, and anterior chamber tap under general anesthesia. The few previously reported cases of traumatic manual avulsion of the globe are reviewed and discussed in the context of the present case. CONCLUSIONS: Partial visual recovery can be achieved after severe orbital and optic nerve trauma. A multidisciplinary approach to the assessment and management of these patients is recommended.