Bergmeister's Papilla Research Articles

Wagner Syndrome-like fundus presentation of atypical Persistent Fetal Vasculature.

To report the case of a woman with atypical Persistent fetal vasculature (PFV) accompanied by more typical findings of Wagner Syndrome. A 58-year-old woman complained about persistent flashes and floaters for more than 6 months. Multimodal retinal imaging showed Bergmeister papilla and a fibrous gray strand floating behind the macula in the right eye. Ultra-wide field retinography revealed a 270° paving-stone degeneration and a nasal circumferential vitreous veil in both eyes. Functional and genetic testing were negative for inherited retinal diseases. PFV spectrum confirms its heterogeneous presentation. We report an atypical adult PFV case in presence of retrolental and optic nerve head stalks, accompanied by extensive peripheral vitreoretinal degenerations. This case may expand the current understanding of PFV presentation in adulthood.

Progressive maculopathy in a child resulting from vitreopapillary traction on a congenitally anomalous nerve.

To present a case of worsening maculopathy and vision loss due to vitreopapillary traction associated with an anomalous optic nerve head in a pediatric patient successfully managed with pars plana vitrectomy. Retrospective case report. A 13-year-old boy presented with unilateral maculopathy that slowly progressed over a four-year period. As his visual acuity declined, he became increasingly symptomatic. The macular pathology occurred in the setting of vitreopapillary traction overlying multiple congenital optic nerve abnormalities, including a myelinated nerve fiber layer and a Bergmeister papilla. Following pars plana vitrectomy to alleviate the traction, the patient's macular appearance improved, and his vision slowly recovered to baseline. There are limited reports of congenital optic nerve anomalies associated with vitreopapillary traction and maculopathy among any age group. This report illustrates a pediatric case in which removal of traction on the nerve head by pars plana vitrectomy was the key therapeutic intervention to alleviate the maculopathy.

OCT angiography findings in posterior persistent fetal vasculature

Aims/Purpose: To report optical coherence tomography angiography findings in a patient presenting unilateral posterior persistent fetal vasculature (PVF).Methods: We report the case of a 19‐year‐old female patient with longstanding visual impairment of the left eye (LE). Patient was assessed with multimodal imaging including color fundus photography, swept source optical coherence tomography (SS‐OCT) and SS‐OCT angiography (SS‐OCTA) of the macula and the optic disc.Results: The patient had a history of unilateral visual impairment of unknown aetiology and consulted for a routine examination. Best corrected visual acuity was 10/10 in the right eye (RE) and limited to counting fingers in the LE. Ophthalmological examination of the LE revealed a mild exophoria, a quiet anterior segment, a vestigial capsular bag and an inferonasal whitish spot at the posterior lens capsule corresponding to Mittendorf's dot. Dilated fundus examination of the LE showed a lack of foveal reflex, retinal vessel contraction associated to the presence of a fibrovascular stalk extending from the OD to the crystalline lens via the vitreous humour, corresponding to fibrovascular contraction of the persistent and hyperplastic Cloquet's canal. No associated retinal detachment was noted. The clinical diagnosis of posterior PVF was confirmed. Macular SS‐OCT revealed retinal thinning with absence of foveal pit. Optic disc SS‐OCT highlighted a hyporeflective tubular structure overlying a Bergmeister'papilla. Cross‐sectional SS‐OCTA detected a flow signal at the level of Bergmeister's papilla, but no confirmed flow signal was identified at the level of the fibrovascular stalk.Conclusions: PVF is a rare condition characterized by fetal remnant from developmental vascular system defects, clinically recognized in its three forms (anterior, posterior and combined). OCT‐angiography is a useful non‐invasive tool to confirm of persistent hyaloid artery patency and assess risk of vascular complications. Contraction of the fibrovascular mass is prone to tractional retinal detachment and repeated episodes of intravitreal or intracapsular haemorrhage. Monitoring is therefore recommended even in adulthood.

Effect of Bergmeister papilla on disc parameters in spectral domain optical coherence tomography

ObjectivesTo investigate the morphological characteristics of Bergmeister papilla (BMP), a persistent hyaloid remnant tissue, and its effects on the measurements and repeatability of spectral-domain optical coherence tomography (OCT).Subjects/MethodsThe subjects of this prospective cross-sectional study including 83 patients with BMP and 76 unaffected individuals, all had open-angle structures. Images, including a 5-line raster and three consecutive optic disc cube scans centred on the optic disc, were acquired using the Cirrus high-definition OCT. BMP’s structural characteristics were classified based on the raster scan images, and repeatability of acquiring optic nerve head and retinal nerve fibre layer parameters acquisition was analysed by calculating the test-retest standard deviation (Sw), coefficient of variance (CV), and intraclass correlation coefficient.ResultsBMPs (n = 83) were categorised into lifting edge (LE) type (63.9%, n = 53), which partially covers the edge of the optic nerve head, and covering disc (CD) type (36.1%, n = 30), which completely covers the cupping area like a cap. The average cup-to-disc ratio (0.58 ± 0.21), vertical cup-to-disc ratio (0.55 ± 0.21), and cup volume (0.22 ± 0.22) of the CD type were lower than those of the LE type (0.66 ± 0.13, 0.64 ± 0.13, and 0.4 ± 0.27, respectively; all P < 0.05). Tolerability indices for repeatability of cup volume (Sw = 0.40 and CV = 0.36) and inferonasal (4 o’clock) retinal nerve fibre layer (Sw = 0.27 and CV = 0.25) in LE-type BMPs exceeded the cut-off value (0.22) and demonstrated stronger correlation with BMP location than that of the controls.ConclusionCaution should be exercised when interpreting OCT findings in eyes with BMP, as BMP can introduce a pitfall in OCT imaging.

Association of Bergmeister Papilla and Deep Optic Nerve Head Structures With Prelaminar Schisis of Normal and Glaucomatous Eyes

To investigate factors associated with the severity of prelaminar schisis (PLS) in heathy subjects and glaucoma patients. Prospective cross-sectional study. A total of 217 eyes of 217 subjects (110 normal eyes and 107 open angle glaucoma eyes) were studied. Frequency and severity of PLS were compared between normal and glaucomatous eyes. Multivariate logistic models were used to assess factors associated with the severity of PLS. Factors considered were age, axial length, glaucomatous damage indices, Bruch membrane opening (BMO) and anterior scleral canal opening parameters, tractional forces (posterior vitreous staging and presence of Bergmeister papilla), circumpapillary choroidal thickness, lamina cribrosa (LC) parameters, and peripapillary scleral (PPS) angle. The frequency of PLS was 70.9% in normal eyes and 72.0% in glaucomatous eyes. There was no difference in frequency and severity between the groups. The presence of Bergmeister papilla was the strongest predictor of a more severe PLS in both normal and glaucomatous eyes (odds ratio [OR]+9.78, 12.5; both P < .001). A larger PPS angle in normal eyes (OR=1.19; P=.003) and a larger BMO area and a deeper LC depth in glaucomatous eyes (OR=1.08, 1.05; both P=.038) were associated with severity of PLS. The severity of PLS was strongly associated with the presence of Bergmeister papilla, suggesting a traction-related phenomenon. Correlation of PLS severity with larger BMO area and deeper LC depth, which are optic nerve head structures associated with glaucoma, suggested its possible relationship with glaucomatous damage.

Intraoperative OCT Angiography in Pediatric Patients with Persistent Fetal Vasculature

To describe abnormalities of the optic nerve microvasculature in patients with persistent fetal vasculature (PFV) and their fellow eyes using OCT angiography (OCTA). Cross-sectional study. Fifty eyes of 25 patients with PFV who underwent prospective imaging using supine OCTA during examination under anesthesia at Bascom Palmer Eye Institute from March 1, 2019, to December 31,2022. OCT angiography images of the optic nerve of the included patients were analyzed with a primary focus on blood flow. Demographic, clinical, and treatment factors were compared with morphologic changes in the optic disc microvasculature. Prevalence of optic nerve microvascular abnormalities on OCTA in the affected and fellow eyes of patients with PFV. A total of 50 eyes from 25 patients were reviewed, and 28% (7/25) met image quality criteria for OCTA analysis. Optic nerve OCTA showed a persistent hyaloid artery (PHA) in all (7/7) PFV eyes analyzed. Of these, flow on OCTA was detectable in 57% (4/7). A Bergmeister papilla was evident in 100% (25/25) fellow eyes, of which flow was detected in 68% (17/25). Fluorescein angiography (FA) demonstrated blood flow within the stalk in 40% (10/25) of PFV eyes and within the Bergmeister papilla in 25% (6/25) of fellow eyes. Similar findings of abnormal blood flow and presence of fibrovascular stalk were seen in both treatment-naïve and treated groups. OCT angiography allows for high-resolution visualization of subtle vascular abnormalities that are not readily apparent using RetCam FA and may serve as a useful noninvasive test to confirm the patency of the PHA and Bergmeister papilla in children. The results of the present study suggest that PFV may be a bilateral and asymmetric process. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Distinguishing Glial Tissue from Optic Disc in Bergmeister's Papilla Using OCT Angiography

A 55-year-old asymptomatic woman was found to have bilateral abnormalities of the optic nerve during an ophthalmic examination. Ocular examination revealed visual acuity of 20/20 in both eyes with normal anterior segment. Fundus examination showed grayish-white glial tissue covering the optic nerve (A) as confirmed by infrared image (B) from OCT. Cross-sectional OCT image (C) exhibited hyperreflective membrane overlying the optic disc, and adhesions to adjacent optic papilla structure (white arrow). The corresponding OCT angiography B-scan with flow overlay (D) showed hyperreflective tissue without any flow signal, contrasting with the optic disc's normal blood flow signal (Magnified version of Figure A-D is available online at www.aaojournal.org).

Bergmeister papilla: A unilateral case report

To described enhanced imaging for visualization of anatomic features and microstructures of Bergmeister papilla within the optic nerve in asymptomatic patient.Primary measure is to see any change in the morphological characteristic in asymptomatic patient with Bergmeister papillae.Secondary outcome measures is to see any effect on parameters of OCT in asymptomatic patient with Bergmeister papillae. Carl Zeiss Cirrus HD 21 Line Raster OCT Model 5000 scanning protocol of the optic nerve and the optic disc cube 200×200 program obtains ONH images through a 3.46-mm diameter circle, and the algorithm automatically detects the circle and positions around the ONH and in the macular region were obtained in the both Eye. Fundus photo performed with Zeiss Fundus visucam 500.Clinical examination was carried out with Carl Zeiss Cirrus HD 21 Line Raster OCT Model 5000 scanning protocol of the optic nerve and the optic disc cube 200×200 program obtains ONH images through a 3.46-mm diameter circle was obtained in the both eye. Zeiss Cirrus HD 21 Line Raster OCT showed hyperreflectivity overlying traction on the right optic nerve with normal Foveal Contour while in the left eye (OS) optic nerve and macula were normal. Fundoscopic examination showed in the right eye(OD), a overlying traction was identified in the optic nerve supero-nasal region, while in the left eye(OS), the fundus was normal. Optical coherence tomography helps in identification of Bergmeister papilla with peripapillary vitreous thickening is beneficial in monitoring vitreo-retinal alterations that may cause future vision impairment.

Persistent fetal vasculature with vascularized cataract and lens cyst

Persistent fetal vasculature may present as anterior, posterior, or mixed type. Its typical features include microphthalmia, retrolental fibrovascular membrane, stretched ciliary processes, Mittendorf dot, total cataract, and Bergmeister papilla. Atypical features described in literature are axial myopia, platyphakia, lentiglobus, and a normal sized cornea. Platy-phakia (Flat-Lens) is a term commonly used for antero-posteriorly flattened crystalline lens. It is a described but extremely rare finding in Persistent Fetal Vasculature and may represent absorption of the lens with fusion of vestigial lens remnants with retrolental fibrovascular membrane.[1] The spectrum of unusual features may also include unregressed vascular vesicular cataractous lens. The visual prognosis in PFV is generally guarded owing to the developmental anomaly and associated amblyopia, strabismus, glaucoma, and retinal pathologies.

The Existence and Regression of Persistent Bergmeister's Papilla in Myopic Children Are Associated With Axial Length.

PurposeThe purpose of this study was to evaluate the existence and regression of persistent Bergmeister's papilla (PBP) in myopic eyes and determine its independent predictors.MethodsThis cross-sectional population-based study included 472 eyes of 236 myopic children. PBPs were identified with swept-source optical coherence tomography (OCT) and were classified into three types (types I, II, and III) according to their morphologic features.ResultsThe mean patient age was 12.13 ± 2.60 years (range = 5–18 years), and 118 (50%) participants were boys. The prevalence of PBPs in our study was 67.8% (160/236). There were significant differences in height, spherical equivalent (SE), and axial length (AL) between the PBP and non-PBP groups (P < 0.05). Type I PBP was noted in 173 eyes (66.8%); type II PBP in 59 eyes (22.8%); and type III PBP in 27 eyes (10.4%). The three PBP types showed significant differences in height, AL, and SE (P < 0.001). Stepwise linear regression analysis indicated that the height (B = 4.497, P < 0.001), PBP existence or not (B = −1.434, P < 0.001), and the types of PBP (B = 0.566, P = 0.041) was an independent predictor for AL, respectively. PBP was detected more frequently in the nasal quadrant than in the inferior quadrant of the disc.ConclusionsPBP regression was closely related to the AL and could be used as a new biomarker to indicate the progression of myopia.Translational RelevanceOur analysis of the presence and morphology of PBP might enable clinicians to judge the progression of myopia.

Optic disc morphology and peripapillary atrophic changes in diabetic children and adults without diabetic retinopathy or visual impairment.

PurposeTo investigate the changes in optic disc morphology and peripapillary atrophy (PPA) in diabetic children and adults without diabetic retinopathy (DR) or visual impairment (VI).MethodsThis cross‐sectional study included two groups of subjects. One group included 91 children with type 1 diabetes mellitus (T1DM) and 86 healthy children, and the other group included 444 adults with T2DM and 442 healthy controls. The optic disc parameters including major and minor axis lengths, optic disc ovality (ODO), optic disc tilt, optic disc area and β‐PPA area were analysed in all subjects. Optic disc rotation and the Bergmeister papilla were analysed only in children. Patients with diabetes and healthy controls were compared in each group of the study population.ResultsIn both groups, patients with diabetes and healthy controls were matched for age, sex and axial length (AL). Among the children, β‐PPA area was significantly smaller in those with diabetes (0.29 ± 0.43 mm2) than in the healthy controls (0.46 ± 0.58 mm2, p < 0.05). Multiple linear regression analysis showed that diagnosis of DM was negatively associated with β‐PPA area. Longer AL and higher body mass index (BMI) were positively associated with β‐PPA area. Among adults, ODO was significantly larger in those with diabetes (1.14 ± 0.09) than in healthy controls (1.12 ± 0.06, p < 0.05). Multiple linear regression analysis showed that the BMI and DM were potential risk factors affecting ODO.ConclusionHyperglycaemia had different effects on the optic disc in children and adults. Unlike in healthy controls, hyperglycaemia had an impact on the peripapillary tissue in children and on optic disc shape in adults before DR and VI development.

Retinal Features in Cynomolgus Macaques (Macaca fascicularis) Assessed by Using Scanning Laser Ophthalmoscopy and Spectral Domain Optical Coherence Tomography.

Cynomolgus macaques are an important and commonly used species in preclinical toxicology studies, but structural reports of in vivo retinal findings are rare in this species. The purpose of this study was to diminish this gap and document optical coherence tomography and scanning laser ophthalmoscopy imaging data in the healthy posterior pole of cynomolgus monkeys' eyes at predose examinations. The current study is a retrospective assessment of baseline spectral domain OCT data obtained from the 768 eyes of 384 cynomolgus monkeys (192 males and 192 females) of Mauritian origin. The data set was obtained from studies conducted over a 4-y period in the context of ocular safety evaluations of various compounds under preclinical development. The most prevalent findings were the presence of Bergmeister papilla and intravitreal hyperreflective spots. Less common findings included disorganization of retinal zones, abnormalities of the retinal vasculature, partial posterior vitreous detachment, and abnormally shaped foveal pits. Thoughtful consideration of these physiologic findings will aid in distinguishing normal features from toxic outcomes in future preclinical ophthalmic studies.

Spectral domain optical coherence tomography evaluation of the feline optic nerve and peripapillary retina

To describe and to establish normative data for the feline optic nerve and peripapillary retina using SD-OCT (Spectralis® HRA+OCT2). Slit-lamp biomicroscopy and rebound tonometry were performed in seven male-intact (0.65±0.02years;4.34±0.33kg) and seven female-spayed (0.74±0.03years; 3.13±0.28kg) cats. All eyes were pharmacologically dilated with 1% tropicamide prior to indirect ophthalmoscopy examination. Animals were then placed under general anesthesia. Optic nerve and peripapillary retinal morphology was evaluated using SD-OCT device by infrared imaging and volumetric scans (circle and radial). Optic disc area, optic cup depth, peripapillary retinal thickness (RT), and retinal nerve fiber layer thickness (RNFLT) were measured. The RNFLT:RT ratio was calculated in the superior, nasal, temporal, and inferior peripapillary region. Intraocular pressure in all cats was 20.68±4.87mmHg (mean±SD). Mean RT and RNFL were thickest in the superior retina (264.7±13.95µm and 70.22±11.78µm, respectively) (P<0.0001). Inferior RT was significantly thinner than nasal and temporal retina (P=0.0013 and P=0.0010, respectively). The RNFLT:RT was significantly higher in the superior retina (0.27±0.04) (P<0.0001). Optic disc area OU was 1.39±0.26mm2 . Optic cup depth OU was 168.36±67.74µm. All parameters tested were not affected by gender, intraocular pressure, body weight, or tested eye. Most eyes had a Bergmeister papilla that was only visible on OCT. Some animals had a recessed area over the center of the ONH meniscus. Normative peripapillary ONH OCT data have been introduced. A Bergmeister papillae is commonly seen in young cats on OCT examination. OCT is a helpful tool to evaluate the retina in cats.

Normal Ocular Ultrasonographic Biometry and Fundus Imaging of Indian Camel (Camelus dromedarius)

The present study was aimed to document the normal measurements of different ocular components of eight adult live Indian camels (Camelus dromedarius) of either sex using B-mode ultrasonography and normal ocular fundus using fundus imaging camera. In all animals, corneal anesthesia was achieved by instilling Proparacaine HCl 0.5% directly on the cornea. Ultrasonographic scanning of eyes was done in sternal recumbency with linear transducer (12–18 MHz) by transcorneal approach. Anterior chamber depth was 0.48+0.006 cm, while vitreous depth was 1.74+0.02 cm. Anterio-posterior depth of lens and Latero-medial diameter of lens were 1.05+0.008 cm and 1.92+0.01 cm, respectively. Globe axial length was 3.29+0.03 cm. Camel eye was aspherical and no significant difference was observed in all the parameters of right and left eyes. Before funduscopy, the pupils were dilated with a short-acting mydriatic such as 1% tropicamide prior to examination. In camels, fundus examination was somewhat cumbersome. The vascular pattern was holangiotic and was similar to other ruminants. Unlike bovines, tapetal non-tapetal differentiation was not clear and sometimes in a single fundus with islands of pigmented and non-pigmented areas could be observed. They usually have a prominent Bergmeister's papilla, which is the posterior remnant of the hyaloid artery.

Enhanced vitreous imaging in healthy eyes using swept source optical coherence tomography.

PurposeTo describe enhanced vitreous imaging for visualization of anatomic features and microstructures within the posterior vitreous and vitreoretinal interface in healthy eyes using swept-source optical coherence tomography (SS-OCT). The study hypothesis was that long-wavelength, high-speed, volumetric SS-OCT with software registration motion correction and vitreous window display or high-dynamic-range (HDR) display improves detection sensitivity of posterior vitreous and vitreoretinal features compared to standard OCT logarithmic scale display.DesignObservational prospective cross-sectional study.MethodsMultiple wide-field three-dimensional SS-OCT scans (500×500A-scans over 12×12 mm2) were obtained using a prototype instrument in 22 eyes of 22 healthy volunteers. A registration motion-correction algorithm was applied to compensate motion and generate a single volumetric dataset. Each volumetric dataset was displayed in three forms: (1) standard logarithmic scale display, enhanced vitreous imaging using (2) vitreous window display and (3) HDR display. Each dataset was reviewed independently by three readers to identify features of the posterior vitreous and vitreoretinal interface. Detection sensitivities for these features were measured for each display method.ResultsFeatures observed included the bursa premacularis (BPM), area of Martegiani, Cloquet's/BPM septum, Bergmeister papilla, posterior cortical vitreous (hyaloid) detachment, papillomacular hyaloid detachment, hyaloid attachment to retinal vessel(s), and granular opacities within vitreous cortex, Cloquet's canal, and BPM. The detection sensitivity for these features was 75.0% (95%CI: 67.8%–81.1%) using standard logarithmic scale display, 80.6% (95%CI: 73.8%–86.0%) using HDR display, and 91.9% (95%CI: 86.6%–95.2%) using vitreous window display.ConclusionsSS-OCT provides non-invasive, volumetric and measurable in vivo visualization of the anatomic microstructural features of the posterior vitreous and vitreoretinal interface. The vitreous window display provides the highest sensitivity for posterior vitreous and vitreoretinal interface analysis when compared to HDR and standard OCT logarithmic scale display. Enhanced vitreous imaging with SS-OCT may help assess the natural history and treatment response in vitreoretinal interface diseases.

Inherited partial aniridia, microcornea with high myopia and Bergmeister′s papilla: A new phenotypic expression

We describe a rare case of familial partial aniridia with high myopia and Bergmeister papilla in five members of a family. Cataract surgery was performed on the proband wherein a brown black spherophakic lens was extracted.

Ophthalmoscopic Characteristics in Sheep and Goats: Comparative Study

The ocular fundus was examined in 40 goat eyes and 40 sheep eyes by studying ophthalmoscopic characteristics and retinograms. Similarities and differing characteristics were described. In common: tapetal colour; peripheral yellowish area surrounding the Winslow stars; unpigmented areas in the non-tapetal zone; a great amount of myelin in the optic disc; the Bergmeister's papilla and the holoangiotic retinal vascular pattern. Differences: big size of the Winslow stars in goats; myelinizated fibre over the non-tapetal zone in sheep; shape, position and myelin distribution of the optic disc; and the presence of a 'primary artery' in goats.

A Nontraumatic Macular Hole in a 10-Year-Old Girl

Full-thickness macular holes usually develop in the elderly population. To the best of our knowledge, there has been no written report of a nontraumatic macular hole in a pediatric patient. A 10-year-old girl noticed decreased central vision in her left eye without any history of trauma. Fundus examination of the left eye revealed a full-thickness macular hole and a thin fibrous membrane on the superior peripapillary retina. She underwent standard macular hole surgery with stripping of the membrane, resulting in closure of the hole. A full-thickness macular hole may develop in pediatric patients. Although the etiology of the macular hole in the present patient is unclear, tangential traction induced by contraction of the peripapillary membrane, presumed to be an incomplete regression of the Bergmeister papilla, might have been responsible for the formation of the macular hole.

The Human Hyaloid System: Cellular Phenotypes and Inter-relationships

We have investigated the expression of leucocyte markers, phenotypic characteristics and cellular relationships of the normal human fetal hyaloid vasculature using immunohistochemistry, light and electron microscopy. Antibodies against von Willebrand Factor, alpha-smooth muscle actin, glial fibrillary acidic protein, vimentin, major histocompatibility complex classes-I and -II, CD45 (leucocyte-common antigen) and calcitonin gene-related peptide were used to identify the cellular constituents of the hyaloid vasculature in whole mounts. Additional morphological features were described at the ultrastructural level.Endothelial cells throughout the hyaloid system were immunoreactive to von Willebrand Factor and major histocompatibility complex class-I antibodies. Pericytes were immunoreactive to alpha-smooth muscle actin antibody; labeled cells were distributed along large branches of the hyaloid artery, vasa hyaloidea propria, tunica vasculosa lentis and pupillary membrane but no immunoreactivity was detected on small connecting capillaries. Vessel and non-vessel-associated hyalocytes on the hyaloid artery, vasa hyaloidea propria, tunica vasculosa lentis, pupillary membrane and vitreous were immunoreactive to major histocompatibility complex classes-I and -II, CD45 and calcitonin gene-related peptide antibodies. Anti-glial fibrillary acidic protein reactivity was detected on Bergmeister's papilla but not on the hyaloid artery. Cells immunoreactive for vimentin were present throughout the hyaloid vasculature including small connecting capillaries. Ultrastructural observations of the hyaloid vasculature revealed junctional complexes, including zonulae adherens, macula adherens and possible zonulae occludens, between adjacent endothelial cells. Fenestrae were not observed in the gestational ages included in the present study.The use of whole mounts in conjunction with specific antisera has provided novel immunohistochemical definitions of the structure and cellular constituents of the human hyaloid. The results indicate that hyalocytes are a heterogeneous population of leucocyte-lineage cells.

Developemnt of the human optic disc: light microscopy.

Human embryonic and fetal optic discs were studied in semi thin sections stained with silver and toned with gold, in a series ranging from 7 to 21 weeks of gestation. The observations suggest that Bergmeister's papilla forms by proliferation of glial cells in the optic disc rather than by sequestration of retinal glia by axons growing through the region. A possible stimulus for such a glial proliferation is hypothesized to be traction on the anterior face of the disc exerted through the primary vitreous. The formation of the glial sheath of the hyaloid artery also appears to be a consequence of traction from the primary vitreous.