A Study in the Variation of Normal Bone Marrow With Reference to Age

Abstract Not Provided

The Nature of Endocrine Exophthalmos

Abstract Not Provided

Certain Aspects of the Vascular Anatomy of the Ocular Inculation and Their Significance in Disease

1. Casts of the choroidal vessels of 20 normal human eyes were prepared by the intravascular injection of Neoprene latex through the ophthalmic artery after preliminary irrigation with water, and the cohesive and elastic properties of Neoprene permitted the dissection of individual vessels and isolated capillary areas from the main vascular mass after fixation in 10% formol saline. 2. The choroidal vessels of 2 normal human eyes were injected with indian ink through the ophthalmic artery after preliminary irrigation, and 7 other eyes were similarly injected following occlusion of a single short posterior ciliary artery. In 2 further eyes indian ink was injected into the choroid through a short posterior ciliary artery. 3. The short posterior ciliary arteries are segmentally arranged and each branch supplies a localised zone of the choroid with an arteriolar-capillary network, but there is no anatomical evidence for the concept that these arteries are true end-arteries. 4. The meeting place at the equator of the posterior choroidal circulation (short posterior ciliary arteries) and anterior choroidal circulation (recurrent arteries from the major arterial circle of the iris, from the long posterior ciliary arteries and from the anterior ciliary arteries) may be marked by an intervening capillary network, but many of the vessels in the anastomosing circulations are in direct continuity with one another. This is contrary to the view that the equator is a zone of defective choroidal vascularisation, and to the view that the anterior part of the choroid is isolated from the rest of the choroid. 5. The peripapillary region of the choroid, although supplied, in part, by fine arterial branches from the intrascleral arterial circle of Zinn, is not isolated from, the rest of the choroid. 6. The size and density of the capillaries in the chorio-capillaris vary in different regions according to their distance from the optic disc, but there is no evidence for the view that the chorio-capillaris underlying the macula has distinctive anatomical features. There are, however, more arterial branches in the submacular region of the choroid than in other regions. 7. There is no anatomical evidence to suggest that the selective localisation of choroidal disease is purely an expression of anatomical peculiarities of certain vascular districts. There is clinical and experimental evidence to suggest that circumscribed areas of choroidal atrophy are due to compression of the chorio-capillaris by exudative dr haemorrhagic extravasations, and this has a bearing on operative procedures involving the choroid. 8. There are no arterio-venous anastomoses in the normal choroid. 1. The choroids of 28 normal eyes were examined after injection of one or both of the central retinal vessels with indian ink, carmine jelly, or Neoprene, following preliminary irrigation of the ocular circulation with water through the ophthalmic artery. 2. The choroids of 51 eyes removed from diabetic persons were examined after injection of one or both of the central retinal vessels with indian ink, carmine jelly, or Neoprene,following preliminary irrigation of the ocular circulation with water through the retinal vessels. 3. Casts of the ocular vessels of 13 normal human eyes were prepared by the intravascular injection of Neoprene latex through the ophthalmic artery after preliminary irrigation with water, and, owing to the cohesive and elastic properties of Neoprene, a detailed dissection was made of the vessels in and around the optic nerve head after removal of the supporting ocular tissue by the action of digestive ferments. 4. Neoprene latex was injected in 3 other eyes, as described above, and the optic nerve head was examined by dissecting the tissues after fixation in 10% formol saline. 5. Indian ink was injected into one or both central retinal vessels in 2 eyes, after preliminary irrigation of the ocular circulation with water through the ophthalmic artery, and the optic nerve head examined by clearing the tissues according to the method of Spalteholz, 6. In a certain number of eyes there are uveo-retinal arterial anastomoses; first, between the central retinal artery and the arterial plexus of the pia mater surrounding the anterior part of the optic nerve, and, secondly, between the central retinal artery and the intrascleral circle of Zinn. These anastomoses are important in a consideration of the pathological events which may follow occlusion of the central artery, and in a consideration of the medical and surgical treatment of such cases. 7. In a certain number of eyes there are uveo-retinal venous anastomoses between the central retinal vein and the choroidal veins. These anastomoses are important to a consideration of the pathological events which may follow occlusion of the central retinal vein, and in a consideration of the medical and surgical treatment of such cases

Quantifying interactions between accommodation and vergence in a binocularly normal population

AbstractStimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (mean±SD age 21.0±1.9years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r2=0.96, p<0.001) and CA/C ratios (r2=0.40, p<0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI −0.06 to 0.24MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI −0.46 to 0.42D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement