Enhanced 10 Gb/s operations of directly modulated reflective semiconductor optical amplifiers without electronic equalization.

We report enhanced 10 Gb/s operation of directly modulated bandwidth-limited reflective semiconductor optical amplifiers. By using a single suitable arrayed waveguide grating we achieve simultaneously WDM demultiplexing and optical equalization. Compared to previous approaches, the proposed system results significantly more tolerant to seeding wavelength drifts. This removes the need for wavelength lockers, additional electronic equalization or complex digital signal processing. Uniform C-band operations are obtained experimentally with < 2 dB power penalty within a wavelength drift of 10 GHz (which doubles the ITU-T standard recommendations).

[Lamellar macular holes with hyporeflective epiretinal proliferation : OCT diagnostics and clinical course]. / Makulaschichtforamen mit hyporeflektivem epiretinalem Gewebe : OCT-Diagnostik und klinischer Verlauf.

BACKGROUND: High-resolution spectral domain optical coherence tomography (SD-OCT) is the standard examination for assessment of lamellar macular holes (LMH). According to the current SD-OCT classification of LMHs, they are characterized by (1) an irregular foveal contour, (2) a defect in the inner fovea, and (3) a separation of inner retinal layers from outer retinal layers of the fovea leading to an intraretinal splitting with loss of retinal tissue. OBJECTIVE: The article aims to give an overview on the current knowledge of retinal imaging in LMH diagnostics and clinical course of disease. MATERIALS AND METHODS: This review is based on current literature and analyses of data from different case series from the Department of Ophthalmology, Ludwig-Maximilian University Munich, Germany. RESULTS: In eyes with LMH, a homogenous atypical, hyporeflective epiretinal tissue has been described in addition to conventional tractional epiretinal membranes (ERM). By SD-OCT, this named lamellar hole-associated epiretinal proliferation (LHEP) does not show common signs of traction and is characterized as a thick homogenous layer of moderately reflective material. LHEP has been demonstrated to be related to the occurrence of photoreceptor layer defects, enlargement of LMH diameter and poor visual acuity. CONCLUSION: The correlation of SD-OCT and en-face OCT can help to identify LMH subgroups and morphology progression early on. FAF enables detection of structural changes at a subclinical stage without visual deterioration. With regard to a high variability of intraretinal changes in LMHs and epimacular fibro-cellular proliferation, the current classification of LMH should be discussed and re-evaluated.

Twin vessels in familial retinal cavernous hemangioma.

We investigated the presence of twin vessels in two patients and in four of their relatives at risk from one family with autosomal-dominant hereditary cavernous hemangioma of the retina associated with central nervous system involvement. Twin vessels were detected in four of the six patients examined. The proband had bilateral retinal vascular hamartomas with central nervous system involvement but no twin vessels. The proband's mother had vascular hamartomas of the retina and brain with twin vessels. In the other three family members, twin vessels were associated either with retinal cavernous hemangiomas (one patient) or with normal fundi (two patients). Because twin vessels may be an ocular manifestation of von Hippel-Lindau disease, their presence in one of our two patients and in the otherwise healthy three family members suggests that twin vessels may be associated with different retinal vascular hamartomas, including capillary and cavernous hemangiomas.

Presumed ocular histoplasmosis syndrome and linear streak lesions.

Five cases of subretinal neovascular membranes in the macula associated with punched out chorioretinal scars and linear streaks were seen in five Dutch patients. Clinically the fundus lesions are consistent with those of presumed ocular histoplasmosis syndrome (POHS) seen in the United States of America. Cutaneous serological testing for histoplasmin reactivity was negative in the three patients tested. Of special interest is the presence of linear streaks in association with POHS. They have not been previously described in patients from Europe with this syndrome.

Experimental short-term tolerance to perfluorodecalin in the rabbit eye: a histopathological study.

PURPOSE: Perfluorocarbon liquids are largely used in vitreoretinal surgery, but their permanence into the eye is considered harmful and early withdrawal is routinely performed by most of the surgeons. We undertook this investigation to evaluate the effects of Perfluorodecalin (PFD) tamponade following vitrectomy in the rabbit eye. METHODS: Twenty-four rabbits underwent vitrectomy of the right eye according with a standard procedure. Eighteen rabbits received PFD and 6 control rabbits received Balanced Salt Solution (BSS) as vitreous substitute. The eyes were examined with light microscopy and transmission electron microscopy after two, four and six days after tamponade and thirty days after the withdrawal of PFD. RESULTS: The tamponade lasting four or more days caused irreversible retinal damage involving the photoreceptors and retinal pigment epithelium. Peculiar impressions were formed in the inner retina at the site of the gravitational effect of PFD droplets. CONCLUSIONS: Based on the results of this study we suggest that the tamponade with PFD lasting more than two days is detrimental to the retina, at least in the case of the rabbit. Damage seems to be related only to the high specific gravity of PFD.

Diagnosis of macular pseudoholes and lamellar macular holes: is optical coherence tomography the "gold standard"?

AIM: To assess fundus autofluorescence (AF) for differential diagnosis of macular pseudoholes (MPH) and lamellar macular holes (LMH) evaluated by optical coherence tomography (OCT) as the "gold standard". METHODS: The files on 50 eyes of 46 consecutive patients diagnosed by OCT as having a foveal defect with residual retinal tissue at the bottom were reviewed. Retinal thickness was measured at the foveal centre and 750 microm temporally and nasally to differentiate further MPH and LMH. The corresponding corrected AF images were then evaluated. Eyes with either macular pucker or stage 1a impending macular hole served as controls. RESULTS: OCT measurements allowed the classification of two different profiles: 28 eyes classified with MPH had macular centres and perifoveal retinas that were significantly thicker than the 22 eyes classified with LMH. The corrected value of the foveal AF intensity was not significantly different between the two groups. In addition, the AF did not correlate with the thickness of the retinal tissue at the base of either MPH or LMH eyes. None of the control eyes showed foveal AF. CONCLUSIONS: The findings suggest that OCT data must be interpreted with caution when differentiating between MPH and LMH. In this series, the two groups showed similar foveal AF. AF imaging may add useful information to the differential diagnosis of MPH from LMH: the presence of foveal AF is consistent with a loss of foveal tissue and therefore a diagnosis of LMH.

Spontaneous resolution of a full thickness idiopathic macular hole: fundus autofluorescence and OCT imaging.

BACKGROUND: To report on the spontaneous closure of a full thickness juxtafoveolar idiopathic macular hole (IMH) monitored with fundus autofluorescence (AF) as well as optical coherence tomography (OCT) imaging. METHODS: Observational case report. Fundus Autofluorescence with a confocal SLO (HRA, Heidelberg Engineering, Germany) and OCT imaging were used to monitor the spontaneous evolution of a stage II IMH. RESULTS: A 70 year-old woman with unremarkable ocular history received a diagnosis of idiopathic macular hole in the left eye. Bright autofluorescence corresponding to the IMH was documented with the confocal SLO and OCT imaging could confirm the presence of an hour glass shaped full thickness juxtafoveolar IMH. Biomicroscopy revealed no posterior vitreous detachment (PVD). Few months later clinical examination demonstrated the presence of typical symptoms and signs of PVD (miodesopsias and Weiss ring). The bright autofluorescence corresponding to the IMH disappeared and OCT imaging documented a normal fovea in morphology and thickness. CONCLUSIONS: Spontaneous closure of full thickness juxtafoveolar IMH can occur and may be properly monitored with fundus AF as well as OCT imaging.

The natural history of juxtafoveal and subfoveal choroidal neovascularization in high myopia.

BACKGROUND: To assess the natural history of juxtafoveal and subfoveal choroidal neovascularization in eyes with high myopia. METHODS: We retrospectively reviewed the charts of 31 patients (31 eyes) with myopia > or = 6 diopters, well-defined juxtafoveal (1-200 microm from the foveal center) or subfoveal choroidal neovascularization (CNV) on fluorescein angiography at baseline, no prior laser treatment, age < or = 55 years and presenting visual acuity (VA) > or = 20/200. Initial and final VA were compared with the Wilcoxon signed rank test. Multifactor analysis of variance was used to assess the association between baseline characteristics of the lesion and final VA. RESULTS: Twenty-two patients were females and 9 males with a median age of 44 years (range 14-55). Median diopters spherical equivalent was -11.5 (range -6, -25). Follow-up ranged from 1 to 20 years (median, 3 years). Nine eyes had juxtafoveal CNV and 22 subfoveal involvement. Median final VA (20/100) was significantly worse than median initial VA (20/50)(p = 0.02). A decrease in VA > or = 2 lines occurred in 18 eyes, whereas 8 eyes remained stable and 5 improved (4 juxtafoveal membranes and 1 subfoveal membrane). Of the 9 juxtafoveal CNV, 7 had a final VA > or = 20/40 after a median follow-up of 4 years. By contrast, only 2 of the 22 subfoveal CNV had a final VA > or = 20/40 (median, 20/100) with a median follow-up of 2.5 years. The only factor associated with better final VA was the initial location of CNV (p = 0.0000). CONCLUSION: This study confirms the poor functional outcome of subfoveal CNV in degenerative myopia with more than 70% of patients having a final VA of 20/100 or less. Juxtafoveal CNV shows a better functional prognosis. These differences should be considered when planning treatment strategies.

Idiopathic sub-retinal neovascular membranes in the macula (hemorrhagic macular choroidopathy of young adults). Clinical report and effectiveness of laser treatment.

Twenty-six patients with idiopathic sub-retinal neovascular membranes (INVMs) located within the posterior pole were examined. Clinical and fluorescein angiographic features of these patients are described. Follow-up ranged from 2 to 96 months (mean 16.5 months). Laser treatment was performed according to the location of the neovascular membrane: 7 out of 9 eyes (77%) increased their final visual acuity or stabilized after Argon blue-green laser photocoagulation (INVMs further than 200 microns from the center of the fovea). Krypton red light laser treatment was performed in 13 eyes with juxta-foveal and sub-foveal INVMs: following treatment 10 eyes (77%) improved by 2 or more Snellen lines or maintained their pre-treatment visual acuity. Because of the fact that the Krypton laser was not yet available, 5 patients were not treated: all of them had sub-foveal (3) or juxta-foveal INVMs (2). The natural history of 4 cases (80%) showed an increase in the final visual acuity in 3 eyes and a steady state in one eye. Pathogenesis and treatment outcome of the disease are finally discussed.

Unilateral retinitis pigmentosa associated with exfoliation syndrome.

A case of a 71-year-old woman showing pigmentary degeneration of the retina associated with posterior subcapsular cataract in one eye, with a normal fellow eye, is presented. Clinical examinations of the patient were performed in order to rule out the various causes which are known to produce funduscopic features that mimic retinitis pigmentosa. Since these investigations were all negative, the fundus changes were interpreted as a unilateral retinitis pigmentosa. One year later, the patient was re-examined and an exfoliation syndrome was discovered in the affected eye, while the fellow eye was unchanged. An association of unilateral retinitis pigmentosa and exfoliation syndrome in the same eye can be regarded as exceptional. The possibility of a correlation of the pathogenetic mechanisms involved in the development of both conditions is discussed.

Fluorescein angiographic findings and results of laser treatment in circumscribed choroidal hemangioma.

We studied retrospectively 12 eyes with a solitary choroidal hemangioma in 12 patients over a period of 13 years. A peculiar, even hyperfluorescence of the tumor within the retinal venous phases occurred in all 12 cases. In all but four patients, laser therapy was performed to reduce subretinal fluid and partially destroy the tumor. Two of the three eyes without extensive retinal detachment or cystoid macular edema at the initial visit regained a final vision of 20/30 or better. The remaining 5 patients with the two major complications had a final vision of 20/80 or worse due to degenerative retinal changes. We believe that laser treatment is definitely advisable in the early stages of a circumscribed choroidal hemangioma.

Diffuse necrotizing retinochoroiditis in a child with AIDS and toxoplasmic encephalitis.

We examined a child with a human immunodeficiency virus (HIV) infection who at 15 months of age developed acute encephalitis, followed 1 week later by a diffuse, uniocular retinochoroiditis. The clinical picture in the right eye was characterized by the occurrence of some intraretinal hemorrhages; punctate, yellow-white, outer retinal lesions temporal to the macula; and a quadrantal, white area of necrotic retina located superotemporally. - The vitreous was remarkably clear, and the left eye was normal. Fluorescein angiography revealed small spots of late hyperfluorescence, vasculitis in the posterior pole, and a persistently hypofluorescent quadrantal superotemporal area. Toxoplasma IgM antibodies that were absent 1 week after birth became detectable in the serum and the cerebrospinal fluid. Serological testing for cytomegalovirus was negative. Neurological signs improved on a specific therapy (pyrimethamine and sulfamethopirazine), but the patient died 2 months later of disseminated cytomegalovirus infection.

Clinical application of digital indocyanine green videoangiography in senile macular degeneration.

Digital indocyanine green videoangiography (ICGV) was done in 34 eyes of 24 patients with aging macular degeneration (AMD), including drusen, either alone (6 eyes) or in association with other AMD changes (9 eyes), geographic atrophy of the retinal pigment epithelium (2 eyes), well-defined choroidal neovascularization (CNV; 3 eyes), occult CNV (12 eyes) and recurrent CNV (11 eyes). Of the 11 eyes with soft drusen, 10 showed abnormal fluorescence in the late ICGV picture. ICGV of the 4 eyes with hard drusen showed no abnormality. The geographic atrophy of the retinal pigment epithelium and choriocapillaris remained hypofluorescent with sharply demarcated boundaries throughout the study. ICGV confirmed the presence of CNV in all 3 eyes with well-defined CNV and in 11 of the 12 eyes with occult CNV. Additionally, all but 1 eye with primary occult CNV and 6 of the 8 eyes with recurrent occult CNV could be reclassified in this study as having well-defined CNV. Overall, ICGV yielded additional information in 17 of the 20 eyes with primary and recurrent occult CNV. Its clinical importance for the evaluation of early stages of AMD has still to be confirmed by future investigations. ICGV is recommended as a diagnostic examination in eyes with CNV poorly defined by fluorescein angiography.

Rip of the retinal pigment epithelium: report of an atypical case.

A 71-year-old man presented with a large disciform scar in the right eye and hard (nodular) as well as soft (granular) drusen scattered throughout the posterior pole of the left eye. A large serous pigment epithelial detachment was evident in the drusen area of the left fundus. Six months later a tear of the retinal pigment epithelium (RPE) occurred in the left eye. It was located exactly along the peripheral border of the drusen area instead of the border of the RPE detachment where it would have been expected. It is considered that reduced adhesion between the RPE and Bruch's membrane as well as the sharp change in tissue cohesiveness at the border of the drusen area and surrounding healthy tissue were relevant in the pathogenesis of this case.

Technical procedures and software for magnification-corrected morphometry of optic disk photography.

In order to obtain a new diagnostic tool for the early diagnosis of glaucoma, we developed a method based on computerized analysis of the optic disk, cup and neuroretinal rim areas. A fundus camera, a personal computer and a graphic tablet are employed. Suitable software was developed for calculating the areas (disk, cup and rim) providing an index, the rim/disk ratio. The method revealed high repeatability and reproducibility. The simplicity and speed of the procedure make this test suitable for routine clinical use in the early diagnosis of glaucoma.

Clinical application of digital indocyanine green angiography in choroidal neurofibromatosis.

Indocyanine green angiography (ICGA) was used to investigate 2 cases of type 1 systemic neurofibromatosis that had appeared at birth with café-au-lait skin spots, gradually developing into multiple cutaneous neurofibromas. Patients underwent periodical visual acuity examinations, the fundus was checked and fluorescein angiography (FA) was done; all findings appeared extremely stable. In 1995 these 2 patients underwent ICGA to check for pathological choroidal involvement. In both cases the initial examination stages showed multiple extensive areas of hypofluorescence, their morphology and extension coinciding with the retinal pigment epithelium (RPE) lesions shown by FA and by ophthalmoscopic examination. In later stages the hypofluorescent areas became smaller, generally shrinking to small isolated dots in the middle of the original areas. These initially hypofluorescent areas appeared to be due to slow focal choroidal filling caused by deep alterations to the walls of the choroidal arterioles induced by the disease. Chronic hypoperfusion of the choriocapillaris results in impairment of the overlying RPE, causing it to atrophy. The late hypofluorescent areas could be either persistent nonperfused lobules of choriocapillaris or neurofibromatose choroidal nodules. ICGA examination showed that the FA lesions described in the literature as choroidal nodules are in fact alterations to the RPE secondary to areas of hypoperfusion in the choriocapillaris.

Dominant inherited tilted disc syndrome and lacquer cracks.

Three patients with the tilted disc syndrome from one family were examined. The presence of the trait in three consecutive generations suggests an autosomal dominant mode of inheritance, although in these patients with variable expression. The propositus showed bilateral inferonasal retinal ectasia, with atrophic subretinal scars. Linear-like lacquer cracks, radiating from the central scars, were also present running parallel to the margin of the optic nerve head. The linear streaks were very similar to those usually seen in traumatic tears of Bruch's membrane. The mechanical stretching of the ectatic area, and its abnormal location inferonasal to the optic disc might have been responsible for the unusual pattern of the lacquer cracks in our patient.

The effect of simultaneous internal tamponade on fluid compartmentalization and its relationship to cell proliferation.

To determine whether the residual free spaces within the vitreous chamber that result after vitreoretinal surgery and internal tamponade may be avoided, and to verify whether such compartmentalization is of real importance in the recurrence of postoperative proliferative vitreoretinopathy (PVR), the use of simultaneous double filling with polydimethylsiloxane (PDMS) and fluorosilicone (FSiO) in the repair of complicated retinal detachment is evaluated in 12 selected cases. Initial retinal reattachment was achieved in all cases. PVR recurred in 10 patients (83%), 6 of whom showed partial retinal detachment. Inferior and superior postoperative residual free spaces were abolished by this procedure, but a new residual fluid space was created, lying horizontally between the bubbles and expanding in a triangular shape nasal to the optic disc and temporal to the macula. Overall, 9 of 10 eyes with PVR after surgery had proliferation involving these areas. These findings support the concept that compartmentalization is of major importance in determining postoperative cell proliferation.

Drusen and 'choroidal filling defects': a cross-sectional survey.

The present study was designed as a cross-sectional survey to assess the association between soft drusen and 'choroidal filling defects'. Sixty-eight eyes presenting hard drusen and 58 eyes with soft drusen of 126 subjects with an age range of 45-83 years were examined in the present study. Choroidal filling defects were present in 13 out of 68 (19.1%) patients with hard drusen and 29 out of 58 (50%) with soft drusen (chi 2 square = 13.4; p < 0.0001 and an odds ratio = 4.2 with 95% CI 1.9-9.3). Age, ocular and systemic hypertension, and diabetes did not influence the results. The association between soft drusen and choroidal filling defects, found in our study, suggests that these abnormalities are possibly due to changes in the staining or permeability properties of Bruch's membrane rather than to a defect in the choroidal blood supply. Soft drusen and choroidal filling defects may both be caused by an accumulation of hydrophobic material within the Bruch's membrane, which is discrete in the case of drusen and diffuse in the case of choroidal filling defects. Choroidal filling defects and soft drusen may represent useful clinical sign of hydrophobicity of Bruch's membrane.