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In the literature there is agreement about the variable prognosis of an ocular perforation, but analysis of the factors which affect the prognosis is rare. In this article the factors which determined the final visual outcome in 60 perforation cases are discussed. One third of the total number of eyes lost useful vision (visual acuity less than 0.1) while 43% retained good sight (visual acuity greater than 0.8). The visual outcome is considered for each prognostic factor. It is striking that the three most unfavourable prognostic factors often occur together: a traffic accident, a large to extremely large perforation and a corneo-scleral localization. Suggestions for the prevention of the most frequent causes are made, and early therapeutic measures are described which should be able to be performed in every large clinic.

Lens-capsule material from healthy and cataractous human lenses and from rabbits was collected with specially designed forceps. Subsequently the capsule fragments were fastened, after short pre-fixation, onto a rubber substrate with small stainless steel tacks, to prevent rolling-up of the fragments during the fixation and drying procedure for the SEM. Finally the capsule fragments were studied by SEM. Marked morphological changes, e.g., irregular swelling (like blebs) of the nuclei, formation of deep grooves at the cell borders and complete loss of epithelial cells, were found in the lens capsules obtained from certain cataractous lenses. Differences in capsule thickness were found in pathological capsule material. The imprints (attachment-lines) of the lens-fibres on the epithelial cells were often difficult to visualize.

A keratoprosthesis (KP) is the last and only surgical resort to regain some visual acuity in eyes with severely damaged corneae. Corneal blindness represents an important percentage of the blind in the economically poor countries. Commercially available KP's, e.g. those made of PMMA, which are difficult to sterilize and vulnerable to surface damage, are too expensive in these countries. To overcome these disadvantages, we developed a new KP, made of a glass core melted into a platinum cylinder with flange. They were implanted unilaterally in eyes of ten Hollander rabbits intralamellarly. They were fixated by two stainless steel traction threads passed around the whole eyeball. We investigated this type of KP in the rabbit cornea, its acceptance by stroma, epi- and endothelium, and its hydro-mechanical dynamics in situ. No signs of infection or extrusion were observed. No epithelial downgrowth, nor adverse tissue reaction could be detected. LM and SEM showed endothelialization of the newly formed stroma around the central column of the KP. We conclude that this type of KP (although optically still to be optimized) has been accepted by the rabbit cornea and a clinical trial on cornea-blind patients is justified.

To describe the finding of circularly grouped hypomelanotic spots in the central macula of a patient with syndromic characteristics. Case report of a patient with albinotic spots grouped within the macula, café au lait spots, and left-sided hemihypertrophy. A 15-year-old boy presented with hypomelanotic spots which were hyperautofluorescent on fundus autofluorescence imaging with no disruption of the retinal laminae or photoreceptor inner and outer segment (IS/OS) junction on spectral domain optical coherence tomography. His developmental history included hemihypertrophy, café au lait spots over his axilla and extremities, and surgically corrected left-sided cryptorchidism. Other ocular history included resolved convergence insufficiency and red–green color blindness. It is essential to recognize that circularly grouped hypomelanotic spots are a benign condition. The location and arrangement of the hypomelanotic spots were atypical for congenital grouped albinotic spots of the retinal pigment epithelium (CGAS) as they were grouped within the macula in addition to a more characteristic linear “bear track” formation in the periphery. To the authors’ knowledge, this is the first report of CGAS present in a patient with hemihypertrophy, café au lait spots, and cryptorchidism and may represent a novel syndromic association.

The fundus lesion described in 1878 as retinal venous thrombosis forms a serious threat to the visual acuity of aging persons. As the average human life span increased this ophthalmological problem gained importance. The natural outcome of the central retinal vein occlusion is generally poor; the disease often ends with poor vision or blindness, in part of the patients associated with neovascularization glaucoma. As thrombus formation is not the primary cause of the development of the fundus lesions the nomenclature ‘retinal vein occlusion’ is preferable to that of ‘retinal vein thrombosis’. This study has been performed as a contribution to the evaluation of photocoagulation as a therapy in retinal vein occlusion. In 1855 Liebreich gave the first description of the ophthalmoscopic picture of ‘thrombosis’ of the central retinal vein, as the result of retinal vein obstruction. Histological studies led to different views on the cause of the vein obstruction. Some authors considered a thrombus to be the primary cause, while others thought the thrombus to be secondary to a proliferative condition caused either by inflammation of the vessel wall or by pressure on the vein. From the beginning of this century attention has increasingly been paid to the aetiological importance of arterial circulatory disturbances based on sclerosis. The lamina cribrosa was considered as an anatomical site of predilection for the development of central retinal vein occlusion. The ophthalmoscopic aspect of branch vein occlusion was first described in 1874 by Leber, who already considered the arteriovenous crossing to play a role in the development of the condition. The characteristics of the retinal vascular system are described. The endothelial cells of retinal veins and capillaries lie so clotse to each other that hardly any intercellular space exists; they form the so-called blood-retinal barrier which is impermeable to fluorescein. The wall of the choriocapillaris is permeable to fluorescein; however, a chorio-retinal barrier is formed by the pigment-epithelial layer. Thus, in normal circulatory conditions, both barriers prevent fluorescein from entering into the retina. The retinal arteries and veins, and their tributaries do not anastomose when circulation is normal. When a vein occlusion occurs it usually takes weeks to months for collaterals to develop; this slow development of collaterals can be detrimental to both structure and function of the retina since the metabolism of the retina easily becomes deficient. The retinal vessels have a common adventitia at the lamina cribrosa and at the crossings, where they form a functional unit, which is of significance in the pathogenesis of retinal vein occlusion. The main subjective symptoms are a decrease in visual acuity, which varies according to the site of the occlusion, and visual field defects corresponding with the drainage area of the occluded vein. The occlusion of the central retinal vein is preceded by a pre-occlusive stage. The former shows a marked papilloedema, dilation and tortuosity of the veins, extensive retinal haemorrhages and cystoid macular oedema associated with a marked drop in visual acuity. In the pre-occlusive stage the fundus lesions are less severe and generally the visual acuity is rather good. In branch vein occlusion the fundus lesions: oedema, haemorrhages and exudates, are limited to that part of the retina which is the drainage area of the occluded vein. The degree of visual loss depends on the involvement of the macular area. Contrary to the uniformly unfavourable course of the fully developed central retinal vein occlusion, the course of pre-occlusion can vary from spontaneous recovery to a change into a fully developed occlusion. In branch vein occlusion the visual prognosis largely depends on the degree of involvement of the macular area. The duration of the visual complaints is not a reliable parameter for assessment of the time of onset of the vein occlusion. Histopathological investigations have been performed mainly on eyes which had been enucleated on account of neovascularization glaucoma. In most cases no thrombus was found. Some authors considered sclerotic changes of retinal arteries to be secondary to the retinal vein obstruction, others held the view that arterial rather than venous lesions were primary, which is supported by the findings in eyes studied shortly after the onset of the vein occlusion. These findings indicate that the occlusive fundus picture is caused by an impairment of the retinal circulation due to sclerosis of both retinal arteries and retinal veins at the sites which are especially susceptible to occlusion: the lamina cribrosa and the vascular crossings. Various therapies have been tried with disappointing results. Systematic potassium iodide combined with pilocarpine eye drops as well as X-ray therapy are now considered to be obsolete. Anticoagulant and fibrinolytic agents, however, are still being used. The first reports of anticoagulant therapy were promising. Subsequent results, however, varied greatly. Some authors reported good results, others found no difference between anticoagulant-treated and untreated patients and some even considered anticoagulant therapy to be noxious. The differences in results can be explained by the heterogeneity of the material as regards age of the patients and types of the occlusions, since in most reports no differentiation was made between pre-occlusion and fully developed occlusion. As the circulatory disturbance is caused by sclerotic narrowing of the vascular lumen and not by a thrombus, it is not surprising that in retinal vein occlusion anticoagulants have failed to give convincing evidence of their therapeutic usefulness. The same applies to the fibrinolytic agents which have been tried. Other ways of treatment, such as intravenously administered novocain, rheomacrodex, corticosteroids, Atromid-S, have incidentically been mentioned in literature but without convincing results. Nicotinic acid derivatives are widely in use but so far no systematic evaluation of their therapeutic value has been reported. Fluorescence angiography has considerably contributed to our knowledge of the dynamics of retinal circulation. The normal retinal vessel wall does not stain with fluorescein and is not permeable to fluorescein; the diseased vessel wall, however, shows a pronounced affinity to fluorescein and in a more diseased state may allow leakage of fluorescein into the retina, which indicates a higher degree of damage to the vessel wall. Choroidal background fluorescence is decreased by hyperpigmentation or haemorrhages; in depigmentation background fluorescence is enhanced. The fluorogram in central retinal vein occlusion never shows complete stagnation nor even a very pronounced retardation of the retinal circulation, which indicates that there is only a relative obstruction of the blood flow. The retinal arteries usually are very narrow, the capillaries are dilated with countless microaneurysms and show intense fluorescence and leakage, especially in the macular area. In the late phase fluorogram a cystoid macular structure can become manifest. Occlusion of capillaries may very rapidly lead to the development of areas of non-perfusion. Optico-ciliary anastomoses and newly formed vessels, which show profuse leakage, may develop in long-standing occlusions. Circinate exudates, a late complication of vein occlusion, do not stain with fluorescein. As compared with the fully developed central retinal vein occlusion, the fluorogram of a pre-occlusion shows little or no papilloedema, less tortuosity and dilation of the retinal veins, less haemorrhages and, generally, less intense macular oedema. A cystoid macular structure can be present even when visual acuity is only slightly impaired. Also in branch vein occlusion the fluorogram shows that the circulation in the occluded vein is only slightly retarted as compared with the other retinal veins. In the late phase fluorogram leakage in the drainage area of the occluded vein causes a diffuse fluorescence. Visual acuity only decreases when oedema affects the macular area; cystoid macular oedema may develop. In long-standing branch vein occlusion distally of the site of occlusion part of the vessel may be obliterated but by then collaterals may have developed. Fluorography is very useful for the evaluation of the results of photocoagulation treatment. Our insight into the pathogenesis of retinal vein occlusion has been enhanced by histological studies, fluorescence angiography, studies of fundus lesions similar to those of retinal vein occlusion, and experimental investigations. Histopathological findings indicate that not thrombus formation but sclerotic lesions both in the retinal arteries and retinal veins, leading to stenosis and circulatory disturbances, are of aetiological importance in retinal vein occlusion. Fluorescence angiography reveals that the retinal vein is not closed. Dilation and tortuosity of the retinal veins and haemorrhages are, therefore, not signs of congestion but are caused by a loss of vascular tonus and increase in permeability of the vessel wall, for which hypoxia is held responsible. Supporting evidence can be derived from the fact that quite a few fundus lesions similar to those of retinal vein occlusion are found in various conditions associated with retinal hypoxygenation, such as hyperviscosity syndromes and arterial circulatory disturbances proximally of the optic disc. The importance of the arterial circulatory disturbances in the development of the occlusive fundus picture is sustained by ample experimental evidence. A raise in oxygen tension of the blood is known to improve retinal oxygenation. A raised oxygen content of inhaled gas, however, decreases the cerebral and retinal blood flow by arterial constriction; this can be counteracted by raising the carbon dioxide content of the inhaled gas. Therefore, carbogen (a gas mixture of 95% O2 and 5% CO2) inhalation has been given. Between January 1970 and January 1974 164 patients with retinal vein occlusion were referred to the Eye Clinic. In 117 of them, 55 men and 62 women, the follow-up was sufficient for an evaluation of the therapeutic results. Fifty-three patients had an occlusion of the central retinal vein. In all 23 patients with a fully developed central retinal vein occlusion the visual acuity was very low (< 4/60) and cystoid macular oedema was present. Out of the 30 patients (32 eyes) with a pre-occlusion only 4 had a visual acuity of < 0.1 ; in 6 eyes (19%) a cystoid macular structure was found. Sixty-four patients had a branch vein occlusion. In 45 patients (68%) the occlusion had occurred in the superior temporal vein and in 19 patients (32%, 21 eyes) in the inferior temporal vein. The visual acuity ranged from 1/300 to 0.8. The ocular fundus was examined by direct and indirect ophthalmoscopy, biomicroscopy with the slitlamp and Goldmann's fundus contact lens, and fluorescence angiography. An extensive general and biochemical examination was performed in all 117 patients; hypertension was found in 80% of the patients. Nine patients (7 7%) had suffered a coronary infarction before the onset of the visual complaints and 2 (1.7%) during the follow-up period. The ECG was abnormal in 24 patients (20.5%). The plasma cholesterol level was more than 280 mg% in 48 patients (41%) and the total plasma lipid level was more than 800 mg% in 32 patients (27%). Diabetes mellitus was found in 10% of the 164 patients. No treatment was given in branch vein occlusion when visual acuity had decreased only slightly and the ophthalmoscopic and the fluorescein-angiographic aspects of the fundus showed only minor lesions, since in such conditions spontaneous regression of the lesions can be anticipated. Anticoagulant therapy was given in co-operation with the ‘Thrombosis Service’ of the Leyden University Hospital. Carbogen inhalation treatment was given to a group of patients with a pre-occlusion of the central retinal vein and as interim treatment to all patients who were admitted for photocoagulation treatment, during the period of general internal and fluorescein-angiographic examination. Photo coagulation was performed with the Zeiss-Oberkochen Xenon arch photocoagulator under retrobulbar anaesthesia. The lowest intensity of the coagulator yielding coagulations which were only just visible was used. A field size of 2° or 3° was generally chosen; for the peripheral areas sometimes field size 4%° was used. The number of coagulations ranged from only a few in small branch vein occlusions to 400 in occlusions of the central retinal vein. Special care was taken to coagulate between the haemorrhages since heat absorption by superficial retinal haemorrhages can lead to nerve fibre bundle defects. In a few patients supplementary coagulation had to be performed after partial resorption of the haemorrhages. Patients with a fully developed central retinal vein occlusion require immediate photo coagulation treatment. Patients with a pre-occlusion of the central retinal vein require immediate treatment when: a. cystoid macular oedema is present and b. the visual acuity is 0.5 or less. A waiting attitude under close observation is justified in pre-occlusion of the central retinal vein when visual acuity is > 0.5 and there is no cystoid macular oedema. In branch vein occlusion immediate photocoagulation is required when: a. visual acuity is < 0.3; b. cystoid macular oedema is present; c. intense oedema, extending all over the macular area, is present; d. a temporal main branch vein is occluded; e. new vessels have developed. In most of the treated patients at least two of the first 4 criteria were present. ‘Delayed’ photocoagulation in branch vein occlusion is indicated when: a. the visual acuity drops to 0.5 or less by extension of oedema or haemorrhages in the macular area; b. new vessels develop. According to their fundus lesions the patients were divided into 3 groups: These groups were subdivided into 4 groups according to the method of treatment: a. no treatment; b. treatment with anticoagulants; c. treatment with carbogen inhalation; d. treatment with photocoagulation. None of the 6 patients with a fully developed central retinal vein occlusion who were not treated improved; the ultimate visual acuity was 1/60 or less. In 7 patients treated with anticoagulants the course was as unfavourable. Out of 11 untreated patients with a pre-occlusion of the central retinal vein only 4 improved, 2 remained unchanged and in 5 the condition deteriorated and passed into a fully developed occlusion within 4–6 weeks. Twelve out of 13 patients with a pre-occlusion of the central retinal vein treated with anticoagulants deteriorated and 1 remained unchanged. Photocoagulation was performed in 22 patients with a fully developed central retinal vein occlusion; 9 of them had a pre-occlusion on first examination which passed into a fully developed occlusion during the period when they were not treated or were being treated with anticoagulants. Whereas none of the 13 patients with a fully developed central retinal vein occlusion who were not treated or treated with anticoagulants attained a visual acuity of more than 1/60, 11 (50%) out of the 22 patients who were treated with photocoagulation attained a visual acuity of 0.1 or more. Four (31%) of the 13 patients who on first examination already had a fully developed occlusion of the central retinal vein attained a visual acuity of 0.1 or 0.2 after photocoagulation, whereas 7 (78%) out of 9 patients who were first seen at the stage of pre-occlusion attained a visual acuity of 0.1 to even 0.5 after photocoagulation. Twenty-five patients with a branch vein occlusion were observed without treatment during an average period of 2 years. This group was composed by selection of the more favourable cases with a relatively good prognosis. The average visual acuity at the beginning of the observation period was 0.37; at the end of the observation period the average visual acuity was 0.52. Thirteen patients (52%) improved, 8 patients (32%) remained unchanged and 4 patients (16%) deteriorated. The 52% improvement rate fits in well with those of other authors, ranging from 42% to 55%. In the 4 patients who deteriorated both the condition of the fundus and the visual acuity improved on photocoagulation treatment. Seventeen patients (19 eyes) with a branch vein occlusion were treated with anticoagulants, which in 5 of them meant continuation of anticoagulant therapy started before the onset of the visual complaints. The results of anticoagulant therapy were: improvement in 6 eyes (31.5%), no change in 7 eyes (37%) and deterioration in 6 eyes (31.5%). The average visual acuity before treatment was 0.25 and on last examination 0.31. Deterioration in 31.5% is in agreement with the results of other authors. Carbogen inhalation treatment was given to 34 patients who were admitted to hospital for photocoagulation treatment. Five patients showed a rise in visual acuity and a decrease of retinal oedema a few days after carbogen inhalation therapy was started; in 2 of them the visual acuity and fundus condition deteriorated again after termination of the carbogen treatment. Photo coagulation was performed in 32 patients with branch vein occlusion. Eighteen of them were treated immediately; in the other 14 patients photo coagulation was performed later on. Eighteen (56.25%) showed cystoid macular oedema and 9 (28%) neovascularization. The average visual acuity was 0.19 before treatment and 0.52 on last examination. Visual acuity improved in 27 patients (84.4%), remained unchanged in 4 patients (12.5%) and deteriorated in 1 patient (3.1%). The 84.4% improvement in the photocoagulation-treated group compares favourably with the 52% improvement in the untreated group. Our results fit in well with those of other investigators. Improvement of visual acuity usually started a few weeks after photocoagulation but in some patients it already set in within a few days. The maximum improvement of vision was achieved after 4 to 5 months, in some cases later. Additional photocoagulation was required in 4 patients. After photocoagulation cystoid macular oedema, present in 18 patients, disappeared in 15, persisted in 2 and developed into a pseudo-hole in 1 patient. Pigment-epithelial dystrophy developed in 12 (67%) of these 18 patients but in only 1 of the 14 patients who had macular oedema but no cystoid structure at the time of photocoagulation. In 13 patients in whom macular oedema cleared after treatment the average visual acuity rose from 0.18 to 0.71. In the 12 patients who developed pigment-epithelial dystrophy the average visual acuity only rose from 0.16 to 0.34. Macular oedema in retinal vein occlusion is particularly important as it is responsible for the decrease in visual acuity and for the secondary macular lesions which cause the loss of vision to become irreversible. When macular oedema is slight the visual prognosis is generally good, as slight oedema tends to regress spontaneously. A more intense macular oedema, as in occlusion of main branches, can rapidly lead to irreversible damage; a very intense macular oedema, as found in central retinal vein occlusion, can, in the course of some weeks, induce the development of cystoid macular oedema. Thus, the development of cystoid macular oedema (C.M.O.) and other macular lesions is correlated both to the intensity and the duration of the macular oedema. This correlation is used in laying down the criteria for performing photocoagulation treatment. The visual prognosis in macular oedema largely depends on the development of secondary lesions, particularly C.M.O. and pigment-epithelial dystrophy (P.E.D.). In all patients with a fully developed central retinal vein occlusion C.M.O. was already present on first examination; it was even present on first examination in 6 eyes (19%) out of 32 eyes with pre-occlusion. In some of our patients with branch vein occlusion C.M.O. developed in the course of 3–6 months. Results of photocoagulation in patients with branch vein occlusion emphasize the unfavourable effect of C.M.O. on the visual prognosis as CM.O. is often accompanied by or followed by P.E.D. in the macular area. Therefore, in the presence of macular oedema photocoagulation should be performed before C.M.O. develops. Circinate retinopathy was seen in only 1 of the 117 patients. This low incidence can be explained by the relatively early treatment of our patients and by the exclusion of diabetic patients from our series. Retinal fibrosis after vein occlusion has been found in 15(12%) out of the 122 affected eyes of our 117 patients; complicating retinal detachment has not been observed. One should guard against too intensive coagulation in areas of retinal oedema, especially in and around the macular area, so as to prevent damage to the nerve fibres, as occurred in one of our patients. Light absorption by haemorrhages in the nerve fibre layer can also cause nerve fibre bundle defects, as happened in another one of our patients. Haemorrhages developed after photocoagulation in 2 patients; in both patients the haemorrhages cleared. Dialysis of the choroid induced by photocoagulation was observed in one patient with central retinal vein occlusion. Anterior segment complications were not observed; occasionally, a shift in the refraction towards myopia was observed, which disappeared within a few days. Despite the relatively drastic nature of photocoagulation, complications are rare and usually have no serious consequences for the patient's vision.

The effect upon the retina of exposure to large fields of bright visible light has been evaluated. The thresholds for permanent retinal damage for four hour exposures in rhesus monkeys have been established for white light, and laser lines of 514.5 nm, 488 nm, 457.9 nm, and 590 nm. The damage has been evaluated by ophthalmosoopy, electroretinography and light and electron microscopy. The shortest wavelength light (457.9 nm) is more effective in causing damage, particularly histological damage, which is spread throughout the fundus and throughout the retinal layers. Functional damage shown by the electroretinogram follows a different action spectrum without the increased effect in the blue. There appears to be more than one mechanism for retinal damage in chronic light exposure, and at least one mechanism is not dependent solely upon the visual pigment and the pigment epithelium. Thresholds of permanent damage appear to be within one or two log units of light levels encountered in the normal visual environment. Newer data suggest that this damage is additive. Daily one hour exposures for four days produce damage equivalent to a single four hour exposure at the same retinal irradiance.