Vitrectomy with Fovea-Sparing Internal Limiting Membrane Peeling for Myopic Foveoschisis.

Background Myopic foveoschisis is a rare form of a tractional maculopathy, which occurs in patients with elevated axial length. The contraction of the posterior hyaloid exerts tangential traction on the retinal surface with a subsequent continuous splitting of the retinal layers. Internal limiting membrane (ILM) peeling has been advocated in foveoschisis, but it has been associated with post-operative macular hole formation. We report on a modified surgical technique, which spares the fovea and may reduce the risk for macular hole formation. Methods Retrospective analysis of 6 patients with myopic foveoschisis. The mean age was 53.8 ± 12.9 years (4M, 2F) and mean myopia was - 18.3 ± 6.5 Dpt. After a 23 g pars plana vitrectomy, the ILM was peeled on the entire macular surface, except in the foveal region lest the thin foveal structures be damaged. All patients received a gas tamponnade with 23 % SF6 and maintained a face down position for 5 days. Results Mean best-corrected pre-operative visual acuity was 0.87 ± 0.56 logMAR, which increased to 0.60 ± 0.40 logMAR at the end of follow-up. The retinal thickness, as measured by optical coherence tomography, decreased from 799 ± 352 micrometers to 318 ± 60 micrometers at the end of follow-up 7.8 ± 5.7 months. No case developed a macular hole. Conclusions Vitrectomy with fovea sparing ILM peeling is a promising surgical technique, which results in an improved foveal anatomy and retinal function. Due to the sparing of the fovea, this surgical technique may reduce the risk of macular hole formation in the post-operative period.

Early changes in optic coherence tomography in a child with laser pointer maculopathy. / Cambios precoces en la tomografía de coherencia óptica en un niño con maculopatía inducida por puntero láser.

CASE REPORT: A 9-year-old boy referred due to visual loss in his right eye after playing with a laser pointer. In the first visit (12hours later) visual acuity (VA) was 0.15. A hypopigmented lesion was present in the fovea, and optic coherence tomography (OCT) showed vertical hyper-reflective bands. In the last visit (6 months later), VA had improved to 0.5, and OCT showed a well-defined area of outer retinal layer disruption. DISCUSSION: An inadequate use of laser pointers can induce severe and permanent visual loss.

Retinal Injury Secondary to Laser Pointers in Pediatric Patients.

This case report describes 4 male children (age, 9-16) who had laser-related retinal injury to the macula of 1 eye or both eyes due to the mishandling of the laser pointer devices at a single vitreoretinal clinical practice. The presenting symptoms associated with laser pointer injury include central vision loss, central scotoma, and metamorphopsia. Clinical findings of laser-related retinal injury include reduced visual acuity, disruption of the photoreceptor ellipsoid zone, retinal pigment epithelium atrophy, and choroidal neovascular membrane formation. Disruption of the foveal ellipsoid zone (photoreceptor inner segment/outer segment layer) is the most common finding on optical coherence tomography imaging. Three patients had potential irreversible vision loss. Laser pointers are readily available and appropriate use of laser pointers in the pediatric population must be emphasized due to the potential irreversible retinal injury. Health professionals, school teachers, and parents should raise public awareness of this emerging public health issue by educating children about the dangers of laser pointers. Laser pointer devices among children should be discouraged and limited due to the possibility of permanent harm to themselves and others. Legislation and laws may be required to better control the sale and use of these devices.

Foveal Damage Due to Subfoveal Hemorrhage Associated with Branch Retinal Vein Occlusion.

To investigate the functional and morphologic prognoses of eyes with subfoveal hemorrhage from acute branch retinal vein occlusion (BRVO), and to examine the effect of intravitreal ranibizumab injection (IVR) on these prognoses, we assessed 81 eyes with acute BRVO, of which 38 did not receive IVR [IVR(-) group], and 43 were treated with IVR [IVR(+) group] for macular edema. The foveal morphologic changes were examined via optical coherence tomography (OCT). At initial examination, 63 eyes exhibited subfoveal hemorrhage. At final examination, the defect lengths in the foveal external limiting membrane (ELM) and ellipsoid lines in these eyes were longer, and final VA was significantly poorer, compared with eyes without subfoveal hemorrhage. In comparisons between the final measurements in eyes with subfoveal hemorrhage in the IVR(-) and IVR(+) groups, while there were no differences in initial ocular conditions, final VA was significantly better in the IVR(+) group. The defects in the ELM and ellipsoid lines in the IVR(+) group were shorter than those of the IVR(-) group (p = 0.002 in both). Final VA was correlated with the defect lengths of foveal ELM and ellipsoid lines in both the IVR(-) and IVR(+) groups (both p < 0.001). In addition, the defect lengths of foveal ELM and ellipsoid lines were closely correlated with the duration of subfoveal hemorrhage (both p < 0.001). BRVO-associated subfoveal hemorrhage caused damage to the foveal photoreceptors, and visual dysfunction. However, IVR improved these prognoses, by accelerating the absorption of the subfoveal hemorrhage.

Acute laser lesion effects on acuity sweep VEPs.

Q-switched neodymium-YAG (infrared) laser lesions at energies up to and including retinal hemorrhages were placed under visual control in the parafovea and the fovea of anesthetized monkeys. Visual-evoked potential (VEP) data were obtained by parallel analog (vector voltmeter) techniques from scalp electrodes in response to high luminance counterphasing sine wave gratings. The gratings were swept downward in spatial frequency to determine an acuity estimate by recording of the VEP magnitude increase onset. Acuity estimates were determined immediately post-exposure and at 15 sec intervals up to 12 min. These were analyzed as a function of laser exposure site and retinal lesion produced. Significant delays in VEP lock-in were demonstrated in subjects that had parafoveal burns or parafoveal subretinal hemorrhages. Foveal burns caused severe short-term fluctuations before a sustained decrease in acuity. Contained foveal hemorrhages produced sustained acuity losses. Foveal exposures that did not produce an immediately visible lesion did not produce measurable changes in VEP response lock-in time. These results probably are independent of visible flash effects and indicate that there may be a transient neural shock effect from parafoveal lesions that can affect the fovea.

Repair and late degeneration of the primate foveola after injury by argon laser.

Each foveola of nine rhesus monkey eyes was subjected to a single, mild, calibrated exposure from an argon laser (1 to 1.4 mW for 10 to 20 min). Observations from ophthalmoscopy, fundus photography, and fluorescein angiography were correlated with light and electron microscopic studies. The ophthalmoscopic changes consisted of initial whitening and subsequent but persistent depigmentation of the foveola. Fluorescein angiography showed a pattern consistent with "window defect" of the retinal pigment epithelium (RPE). In the first 6 months after injury, the pathologic changes consisted of initial vacuolar changes of the RPE, followed by persistent hypopigmentation and slow development of membranous bodies or lipoidal degeneration in these cells. Initial alteration and subsequent incomplete reformation of cone outer segments were also noted. In animals sacrificed 3 to 4 years after injury, separation of RPE from Bruch's membrane, with production of various abnormal basement membranes and intercellular cystoid changes in the overlying retina, was observed. The morphologic observations suggest that although the mildly injured epithelial cells may recover, they may develop functional incompetence at a later date, resulting in serous detachment of RPE and foveal (macular) edema.

Optic disc, foveal, and extrafoveal damage due to surgical separation of the vitreous.

OBJECTIVE: To evaluate the morphologic outcomes resulting from surgical vitreoretinal separation in young adult primates. MATERIALS AND METHODS: Vitrectomy and mechanical separation of the vitreous from the internal limiting lamina (ILL) of the posterior retina and surface of the optic disc were performed on 25 young adult cynomolgus monkey eyes in vivo. Lectin histochemical studies were used to evaluate the vitreoretinal interface. Morphologic outcomes were tabulated. RESULTS: In 11 of 25 eye regions, residual vitreous remained attached to the ILL in some of the regions. Localized ILL breaks or separation of the ILL from the neural retina was noted in 9 eyes. Retinal tissue loss, including avulsion of the ganglion cell, inner plexiform, or inner nuclear layers, was observed in 7 eyes. Avulsion of axon bundles in the optic disc was noted in 9 eyes. Significantly, partial- or full-thickness foveal tears were noted in 11 eyes. Based on the surgeons' intraoperative observations, small superficial optic disc or retinal hemorrhages were observed in 3 of 25 eyes. None of the eyes on which a vitrectomy alone was performed showed ILL damage, or retinal or optic disc tissue loss. CONCLUSION: Damage may occur to the optic disc, fovea, and extrafoveal retina as a result of surgical separation of the vitreous from the retina in young adult primates. CLINICAL RELEVANCE: These data support the contention that surgically induced damage at the level of the vitreoretinal interface may help explain the visual field defects noted after surgery to close full-thickness macular holes. These data also support the need for developing additional modalities to assist in vitreous separation, thereby reducing the risk of traumatic complications associated with purely mechanical procedures.

Analysis of animal models of macular edema.

Various models of macular edema have been studied; however, frank development of a prototypical cystoid macular edema has not been observed. In humans, cystoid edema is frequently observed in association with other disturbances of the retina. Thus, a basic drawback of the animal models may be that an otherwise healthy retina is capable of resolving the experimentally produced edema, thereby preventing chronic cystoid maculopathy. A review of macular edema models and of experimental retinal and brain edema investigations suggests that blood-retinal (blood-brain) barrier permeability abnormalities need to be accompanied by ineffective edema resolving mechanisms for the production of a chronic edema. Intraglial uptake of extravasated serum proteins has been hypothesized to be an edema-resolving mechanism in brain edema. As such, the hypothesis that the Müller cell may be important to edema resolution appears attractive. Future animal model studies should include methodologies whereby edema resolution mechanisms are impaired.

Accidental Nd:YAG laser injuries to the macula.

PURPOSE: To study the clinical course of accidental, single-focus Nd:YAG laser injuries to the macula. METHODS: We reviewed the clinical course of five eyes (four patients) that sustained macular injuries from a Nd:YAG laser. All patients were examined within 24 hours of injury and were observed without surgical intervention for a mean of 20 months (range, 12 to 32 months). RESULTS: A single full-thickness foveal or parafoveal retinal hole was apparent in all eyes either on initial examination or within two weeks of injury. All macular holes were within 650 microns of the foveal center. The mean final visual acuity was 20/60 (range, 20/25 to 20/400) and was related to the distance between the macular hole and the foveal center. None of the eyes developed either subretinal neovascularization or clinically significant epiretinal membrane formation during the study period. CONCLUSIONS: Despite initial poor visual acuity in patients who had a full-thickness foveal or parafoveal retinal hole, visual acuity improved without treatment when the site of the laser injury was located outside the foveal center.

Adaptation of saccades and fixation to bilateral foveal lesions in adult monkey.

Bilateral foveal lesions were made by laser photocoagulation in adult monkeys. One day post-lesion, animals fixated with a new retinal locus inferior to the fovea (in the visual field) that they used permanently. Fixation stability improved modestly over two days. Initially, saccades maladaptively brought the lesioned foveae to visual targets. Over at least several weeks, saccade trajectories gradually changed bringing targets to intact retina, although some animals never totally adapted. The slow time course of saccadic adaptation to foveal loss suggests a mechanism different from that documented in other studies of saccadic adaptation and from that used by the fixation system.

A comparative histopathological study of argon and krypton laser irradiations of the human retina.

A series of comparative exposures to both argon and krypton lasers have been made at 3 locations in a human retina--the fovea, the macula, and intraretinal vessels. In the fovea argon irradiations resulted in damage to both the inner and outer retinal layers as a result of absorption within the pigment epithelium and the macular pigment, while krypton exposures damaged the outer retina and the choroid. In the macula both systems resulted in damage to the outer retina, and again sufficient krypton radiation passed into the choroid to induce blood vessel occlusion, haemorrhage, and oedema. When intraretinal vessels were irradiated, only with argon was sufficient energy absorbed within the vessels to damage them or their surroundings in the inner retina. The implications of these findings are discussed in relation to the therapeutic uses of lasers.

Photocoagulation of the fovea.

The visual outcome, histopathology, and electrodiagnostic tests of a man with a malignant melanoma of the choroid who received foveal argon laser photocoagulation prior to enucleatiion are described. The low intensity foveal burn destroyed only the outer retinal layers and spared the inner retina. Vision was reduced to 20/50 immediately, but recovered to 20/30 after one day. The visually-evoked-potential (VEP) was altered in both amplitude and waveform by the small foveal burn. A patient with solar retinopathy and permanent visual loss demonstrated only waveform changes on VEP testing. Monkeys with mild experimental foveal burns demonstrated outer layer retinal damage and waveform changes on VEP testing. The retinal energy density threshold for argon laser photocoagulation of the fovea is lower than 0.13 joules/mm.2.

[Accidental laser burn]. / Impact laser accidentel.

A student suffered an accidental parafoveal laser burn during a physics experiment. We discuss here the clinical features and management and follow-up. This case presents a good example of photic injuries which can occur in many different settings.

Cone photoreceptor neuroprotection conferred by CNTF in a novel in vivo model of battlefield retinal laser injury.

PURPOSE: To develop a reproducible laboratory model to simulate a battlefield foveal laser injury and to test potential neuroprotective effects of a single injection treatment that might be administered in a military setting. METHODS: Frequency-doubled 532-nm Nd:YAG laser was used to induce a threshold retinal injury bilaterally in transgenic reporter mice that have fluorescent cones. Intravitreal injection of ciliary neurotrophic factor (CNTF) was then administered to the lasered eye and compared with a contralateral sham injection of saline. The effect on fluorescent cone cell survival was quantified using a confocal scanning laser ophthalmoscope (cSLO), TUNEL assays, and quantitative real-time PCR (qPCR). RESULTS: At 3 weeks post-laser, cSLO imaging showed that the proportion of surviving cones expressing green fluorescent protein (GFP) was greater in CNTF-treated (54.1 ± 5.15% of baseline count) than in sham-injected eyes (28.7 ± 4.4%), which was accompanied by a reduction in TUNEL-positive cells. This difference in cone survival persisted at the 6-week point (treated, 39.6 ± 3.2% versus sham, 18.0 ± 3.8%). These changes were accompanied by a reduction in TUNEL-positive cells. The Bcl-2/Bax ratio was increased in CNTF-treated eyes at 1 week postlaser exposure relative to controls. CONCLUSIONS: A single intravitreal injection of CNTF protein was shown to improve cone survival when administered immediately after laser exposure. Similar treatments with CNTF might also have a role in attenuating retinal laser damage sustained by combat personnel in the military setting.

Traction-induced foveal damage predisposes eyes with pre-existing posterior vitreous detachment to idiopathic macular hole formation.

AIM: To propose a new mechanism for the development of idiopathic macular hole in the setting of pre-existing posterior vitreous detachment (PVD). METHODS: Patients were examined clinically with fundus contact lens biomicroscopy and high-definition optical coherence tomography (OCT) was used to characterize the structural changes in the fovea following PVD. RESULTS: Two patients presented with vitreofoveal separation and were found by high-definition OCT to have subtle foveal disruption and irregularity of the foveal contour with no evidence of a full thickness macular hole. Sequential examination of these patients demonstrated delayed formation of idiopathic macular hole. CONCLUSION: Traction-induced inner foveal damage occurring before or coincident with spontaneous vitreofoveal separation destabilizes the fovea and predisposes some eyes to delayed macular hole formation.