Solar retinopathy in children.

PURPOSE: To describe the visual acuity, fundus appearance, and spectral domain optical coherence tomography (SD-OCT) findings in 5 eyes of 3 children with foveal damage from solar retinopathy. METHODS: This was a prospective, observational case series of children who presented to the emergency department at the Royal Victorian Eye and Ear Hospital after having directly viewed the Sun during the transit of Venus on June 6, 2012, or the partial eclipse of the Sun on November 14, 2012. All patients underwent visual acuity testing, dilated fundus examination, and SD-OCT imaging. RESULTS: The 3 patients' ages at presentation were 8, 10, and 11 years. Best-corrected visual acuity in the affected eyes ranged from 20/20 to 20/40 on presentation. Significant foveal pathology was identified on SD-OCT in all 5 eyes, even when visual acuity was normal. At presentation, all eyes showed disruption of the photoreceptor ellipsoid zone and the interdigitation zone on SD-OCT. Additionally, in those eyes with decreased visual acuity, there was disruption of the outer nuclear layer and/or external limiting membrane. At 3-5 months' follow-up, the outer nuclear layer and external limiting membrane lesions had resolved; however, in some eyes the ellipsoid and interdigitation zone abnormalities persisted at 5 months' follow-up, even in the presence of best-corrected visual acuity as good as 20/12.5. CONCLUSIONS: Solar retinopathy in children can cause persistent damage to multiple retinal layers despite recovery of good visual acuity.

Double peeling during vitrectomy for macular pucker: the Charles L. Schepens Lecture.

Epiretinal membranes are commonly encountered in retinal practice, and they result in decreased vision. The present work addresses whether peeling of the internal limiting membrane is necessary during vitrectomy for macular pucker. We performed a retrospective analysis to investigate the effects of "single peeling," in which only the epiretinal membrane was peeled, and "double peeling," in which the internal limiting membrane was also stained and peeled. Although significantly more patients in the single-peeling group had an epiretinal membrane remaining in the central fovea postoperatively, visual acuity was not found to differ between the 2 groups in the short term. Patients who had an epiretinal membrane for more than 18 months had significantly worse visual acuity outcomes. Unexpectedly, there was a greater proportional decrease in central macular thickness in the single-peeling group than in the double peeling group, a finding that deserves further study.

Optic disk pit morphology and retinal detachment: optical coherence tomography with intraoperative correlation.

BACKGROUND: The pathogenesis of optic nerve head pits and associated retinal detachment, and the most effective surgical intervention when visual loss develops, remains unclear. METHODS: The morphology of the optic disk in patients with pits was investigated with optical coherence tomography. For those who underwent surgical treatment for pit-associated retinal detachment, the efficacy of treatment by vitrectomy and separation of the posterior hyaloid, with and without additional peeling of peripapillary tissue, was assessed. RESULTS: On optical coherence tomography imaging, 14 of 18 pits (78%) demonstrated a localized pit-like invagination, whereas 3 (17%) had disks with a generally excavated structure. For 16 of 18 pits (89%), there was evidence of condensed vitreous or glial tissue seen extending from the pit or inside the optic disk. Nine eyes with retinal detachment underwent vitrectomy, posterior hyaloid separation, and endolaser. The retinal detachment completely resolved in 6 of 6 cases where the surgeon additionally peeled the fibrous tissue from the pit and 2 of 3 cases where this was not performed. CONCLUSION: Spectral domain optical coherence tomography demonstrates the varying morphology of optic pit anatomy. Condensed vitreous strands or glial tissue in the optic nerve pit may also contribute to retinal detachment development.

The bisretinoids of retinal pigment epithelium.

The retina exhibits an inherent autofluorescence that is imaged ophthalmoscopically as fundus autofluorescence. In clinical settings, fundus autofluorescence examination aids in the diagnosis and follow-up of many retinal disorders. Fundus autofluorescence originates from the complex mixture of bisretinoid fluorophores that are amassed by retinal pigment epithelial (RPE) cells as lipofuscin. Unlike the lipofuscin found in other cell-types, this material does not form as a result of oxidative stress. Rather, the formation is attributable to non-enzymatic reactions of vitamin A aldehyde in photoreceptor cells; transfer to RPE occurs upon phagocytosis of photoreceptor outer segments. These fluorescent pigments accumulate even in healthy photoreceptor cells and are generated as a consequence of the light capturing function of the cells. Nevertheless, the formation of this material is accelerated in some retinal disorders including recessive Stargardt disease and ELOVL4-related retinal degeneration. As such, these bisretinoid side-products are implicated in the disease processes that threaten vision. In this article, we review our current understanding of the composition of RPE lipofuscin, the structural characteristics of the various bisretinoids, their related spectroscopic features and the biosynthetic pathways by which they form. We will revisit factors known to influence the extent of the accumulation and therapeutic strategies being used to limit bisretinoid formation. Given their origin from vitamin A aldehyde, an isomer of the visual pigment chromophore, it is not surprising that the bisretinoids of retina are light sensitive molecules. Accordingly, we will discuss recent findings that implicate the photodegradation of bisretinoid in the etiology of age-related macular degeneration.

Disruption in Bruch membrane in patients with Stargardt disease.

PURPOSE: To describe the spectral domain-optical coherence tomography (SD-OCT) findings of two patients with complete defects in the retinal pigment epithelium (RPE) with disruptions in Bruch membrane in Stargardt disease (STGD1). METHODS: Two patients with STGD1 were referred to our clinic for further evaluation. Fundus autofluorescence (FAF), spectral domain optical coherence tomography (SD-OCT), electroretinography (ERG) and Microperimetry (MP-1) were performed to assess the retinal anatomy and function. Screening for mutations in the ABCA4 gene was carried out and detected mutations were confirmed by direct sequencing. RESULTS: Both patients had bilateral macular geographic atrophy (GA) and yellowish subretinal pisciform flecks and mutations were detected in the ABCA4 gene by chip screening. SD-OCT revealed marked atrophy of the retina in the central macula, with focal defects in the RPE with disruptions in Bruch membrane and herniation of the retina through the defect in three of four eyes. CONCLUSION: This case report highlights the necessity for a detailed ophthalmic examination including SD-OCT of patients with STGD1.

Electroconvulsive therapy-induced persistent retrograde amnesia: could it be minimised by ketamine or other pharmacological approaches?

BACKGROUND: Certain pharmacological agents administered during electroconvulsive therapy may have the potential to prevent persistent retrograde amnesia induced during electroconvulsive therapy. This review examines mechanisms for electroconvulsive therapy-induced retrograde amnesia, and evaluates the suitability of the anaesthetic ketamine for preventing this amnestic outcome. METHODS: A review of human studies, animal models and theoretical models in light of memory dysfunction following electroconvulsive therapy was conducted. MEDLINE was searched from 1950 to April 2009 using the MeSH terms "electroconvulsive therapy", "memory", "memory short term", "memory disorders", "excitatory amino acid antagonists", and "ketamine". PREMEDLINE was searched using the terms "electroconvulsive therapy", "amnesia" and "ketamine". Additional keyword and reference list searches were performed. No language, date constraints or article type constraints were used. RESULTS: Disruption of long term potentiation as a mechanism for electroconvulsive therapy-induced retrograde amnesia is well supported. Based on this putative mechanism, an N-methyl-D-aspartate receptor antagonist would appear suitable for preventing the retrograde amnesia. Available evidence in animals and humans supports the prediction that ketamine, an anaesthetic agent and N-methyl-D-aspartate receptor antagonist, could effectively prevent electroconvulsive therapy-induced persistent retrograde amnesia. Whilst there are concerns about the use of ketamine with electroconvulsive therapy, such as possible psychotomimetic effects, on balance this anaesthetic agent may improve or hasten clinical response to electroconvulsive therapy. CONCLUSIONS: A clinical trial is warranted to determine if ketamine anaesthesia during electroconvulsive therapy can lessen persistent retrograde amnesia and improve therapeutic response. Electroconvulsive therapy with ketamine anaesthesia may provide effective antidepressant action with minimal side effects.