Search Results - "International Ophthalmology"

1573-2630

Epidemic ; folic acid ; nutrition ; optic neuropathy

Springer Online Journal Archives 1860-2000

Medicine

Abstract We made two trips to Cuba, as part of an invited international delegation, to investigate an epidemic of optic neuropathy-induced blindness. We worked closely with Cuban scientists and clinicians in their efforts to understand and then deal with 50,000 cases of blindness and an entire population at risk. This gave an unparalleled opportunity to understand the Cuban system of ophthalmologic health care and, in particular, to appreciate the responses of the scientific and health care communities to this crisis. Several features of the very different Cuban medical and scientific infrastructure were both problematic and advantageous as they affected the Cuban efforts to understand, contain and treat this remarkable epidemic.

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1573-2630

choroid ; macula ; circulation ; degeneration

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose. To investigate the macular choriocapillary circulation (MCC) in eyes with age-related macular degeneration (ARMD) and to correlate these findings with the associated clinical and angiographic drusen characteristics. Methods. Scanning laser ophthalmoscope fluorescein videoangiography was performed on 34 eyes with age-related macular degeneration and eight age-matched normal volunteers. Drusen characteristics were assessed using the Wisconsin age-related maculopathy grading scale. Results. A delayed macular choriocapillary circulation (DMCC) was defined as a macular choriocapillary filling time greater than 3 standard deviations from the normal mean (greater than 5 seconds). Nine (26%) of the 34 eyes with ARMD were found to have a DMCC. After age adjustment, eyes with DMCC were more likely to have geographic atrophy of the retinal pigment epithelium (p = 0.003) or choroidal neovascularization (p = 0.07) than were eyes with a normal MCC. Regional differences in choriocapillary filling times were present in the eyes with a DMCC, including nasal-to-temporal, central-to-peripheral, and inferior-to-superior gradients of progressively less choriocapillary filling delay. The DMCC correlated with the location, number, size, confluence, and fluorescein staining characteristics of the associated drusen. Conclusion. DMCC occurs in some eyes with ARMD. This finding may not only assist in defining eyes at risk for progressive disease but may also help to elucidate the pathogenesis of age-related macular degeneration.

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1573-2630

morning glory disc ; retinal detachment ; vitrectomy ; perfluorodecalin

Springer Online Journal Archives 1860-2000

Medicine

Abstract Pars plana vitrectomy was performed on a six-year-old boy with complete retinal detachment associated with a morning glory disc of his left eye. Perfluorodecalin was injected to unfold the retina. During surgery, perfluorodecalin leaked repeatedly under the retina. This case demonstrates that a retinal hole in tissues lying within the optic disc anomaly provides a communication for fluid and perfluorodecalin between the subretinal space and vitreous cavity resulting in a rhegmatogenous retinal detachment in the morning glory syndrome.

Electronic Resource

1573-2630

proliferative vitreoretinopathy ; 5-fluorouracil ; biodegradable device ; intraocular drug delivery

Springer Online Journal Archives 1860-2000

Medicine

Abstract Treatment of proliferative vitreoretinopathy (PVR) requires a multidimensional approach. Recent studies have focused on pharmacologic techniques to inhibit intraocular cell proliferation by applying antimetabolite drugs. Side effects associated with these drugs and difficulties in achieving effective concentration inside the eye make drug delivery an important and difficult part of this approach. We have developed a sustained-release bioerodible device with modifiable release properties for intraocular drug delivery. In this study, we evaluated the efficacy of the device with two different concentrations of 5-fluorouracil (5-FU) in an experimental model of PVR in rabbit eyes. Both devices showed significant (P 〈 0.05) efficacy in prevention of PVR. Devices containing 20% 5-FU (total of 1 mg) were 100% effective in prevention of tractional retinal detachment. No significant complications, other than mild vitreous hemorrhage in a few cases, were associated with this method. Because pharmacologic therapy is used as an augmenting method to surgical therapy, these devices can be easily implanted inside the eye through a sclerotomy at the completion of surgery without any discomfort to patients. Slow release of drug by this method reduces the incidence of toxicity and increases the efficacy by providing a constant concentration of drug during the active period of the disease.

Electronic Resource

1573-2630

silicone oil ; ultrasound biomicroscopy ; vitreoretinal surgery

Springer Online Journal Archives 1860-2000

Medicine

Abstract We evaluated the ultrasound biomicroscopy findings and the amount and location of silicone oil residue in anterior structures of the eye before and after silicone oil removal. We examined the anterior structures in 40 silicone oil 1000 cs-filled eyes at the end of silicone oil tamponade time (mean silicone oil tamponade duration 5.1 months), and in the same eyes after silicone oil removal. High resolution ultrasound biomicroscopy, 50 MHz transducer, 50 νm of resolution, was used. Silicone oil droplets - often not ophthalmoscopically visible - appeared as highly reflective images with after ringing effect. They were present in the anterior structures of the eye in up to 95% of eyes with silicone oil in the vitreous cavity, and in up to 87.5% after careful silicone oil removal. With ultrasound biomicroscopy it was possible to identify small silicone oil droplets with a typical morphological appearance. Once silicone oil is used in vitreoretinal surgery, its complete removal from the anterior structures of the eye is very difficult to achieve later on.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-2630

pseudofacility ; fluorophotometry ; aqueous humor flow ; ultrafiltration

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose: Pseudofacility (decrease in aqueous humor flow in response to increase in the intraocular pressure (IOP)) has been evaluated in animals and in humans by a combination of different techniques that seriously alter the ocular physiology, such as the cannulation of the eyeballs, use of radioactive isotopes, perilimbic suction cups or tonography. Very different results have been obtained. Our objective is to relate the value of the aqueous humor flow in humans (as measured by fluorometry) with IOP. In order to obtain the widest range of IOP possible, we have performed this study in both normal as well as glaucoma patients. Methods: 48 eyes were studied, corresponding to 31 subjects (mean age 58 ± 14 years). Of these, 21 corresponded to normal subjects and 27 to glaucoma patients. The aqueous humor flow (F) was determined by fluorophotometry (Protocol of Yablonsky) and the IOP was measured thereafter. Results: The mean value of F was 2.1 ± 0.5 μl/min for healthy eyes and 2.2 ± 0.7 μl/min for glaucoma-affected eyes. The values were not different (p 〉 0.1). The mean value of the IOP was 15.3 ±3.1 mmHg in the normal population and 22.1 ± 4.3 mmHg in the glaucoma patients. A linear relationship between F and IOP was found (r = − 0.41, p 〈 0.05, decrease in F = 0.081 μl min−1 mmHg−1). Conclusions: The value of the pseudofacility in the humans can be estimated at 0.081 μl min−1 mmHg−1, which constitutes 27% of the total outflow facility. This figure also makes it possible to estimate the role of the ultrafiltration in blood in the production of the aqueous humor since it is assumed that active secretion is pressure-independent. The results obtained are concordant with a secondary but no unimportant role of the plasmatic ultrafiltration with respect to the active secretion.

Electronic Resource

1573-2630

blood aqueous barrier ; methylprednisolone hemisuccinate ; laser flare photometry ; cataract surgery

Springer Online Journal Archives 1860-2000

Medicine

Abstract The aim of this double-blind randomized study was to assess the effect of subconjunctival methylprednisolone hemisuccinate (MH) on the recovery of the blood aqueous barrier (BAB) following uncomplicated cataract surgery performed by the same surgeon in normal eyes. Fifty eyes of fifty patients (28 female, 22 male, mean age 72.3 ± 11.2 years) were randomized into two groups: group 1 received a subconjunctival injection of MH (40 mg in 0.5 cc) at the end of the surgery and group 2 did not. All patients were free of other ocular or systemic diseases known to alter the BAB and were not taking any anti-inflammatory medications. Postoperative treatments were similar in both groups. The patients were submitted to laser flare photometry 30 minutes to one hour after mydriasis with a drop of tropicamide preoperatively and on the first, second and seventh day and then one month and six months following surgery. No difference in aqueous flare was seen between the two groups on any of postoperative visits. These data suggest that subconjunctival MH has no beneficial effect in postoperative BAB permeability following uncomplicated cataract surgery in normal eyes.

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1573-2630

retinal detachment ; proliferative vitreoretinopathy ; proliferative diabetic retinopathy ; silicone oil-gas exchange ; fluid-gas exchange ; vitreous hemorrhage

Springer Online Journal Archives 1860-2000

Medicine

Abstract We performed a prospective randomized clinical study to compare intravitreal silicone oil vs. gas (20% C3F8 or 30% C4F8) in the management of complicated retinal detachments and vitreous hemorrhage. Despite similar anatomic and visual results, the gas-treated group had significantly more instances of vitreous hemorrhage, late elevated intraocular pressure, and localized retinal detachment as postoperative complications than those receiving oil injections (P〈.05). Silicone oil injections containing less than 3.0ml contributed significantly to postoperative detachments (P〈.05).

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1573-2630

ocular tuberculosis ; drug abuse ; tuberculosis panophthalmitis

Springer Online Journal Archives 1860-2000

Medicine

Summary Tuberculous endophthalmitis is a rare condition not described to date in association with intravenous drug abuse. Characteristics such as the lack of proven tuberculous disease in other organs and intense progression towards panophthalmitis make this case all the more interesting. The histopathological diagnosis is based on the identification of acid-alcohol resistant bacilli, and typical granuloma lesions with focal caseosis in stained sections.

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1573-2630

cone dystrophy ; Stargardt ; inheritance ; color vision ; electroretinography

Springer Online Journal Archives 1860-2000

Medicine

Abstract The cone dystrophies can be subdivided into 3 functional stages: central cone disease, peripheral cone disease and diffuse cone disease, respectively. In the patient material of our clinic the sex distribution of patients presenting with te diffuse cone disease stage was abnormal: 22 males and 3 females. The authors suggest that the diagnosis X-linked cone dystrophy often is overlooked.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-2630

erbium-YAG ; laser ; photoablation ; fiberoptic

Springer Online Journal Archives 1860-2000

Medicine

Abstract We evaluated the effects of the erbium:YAG laser (2.9 μm wavelength) on ocular structures. Energy was successfully transmitted through a fiberoptic bundle for intraocular and extraocular applications. The wavelength was strongly absorbed by ocular tissues, producing ablations with minimal thermal damage. Our results indicated that the erbium: YAG laser may have potential uses as a photoablative tool to reshape the corneal surface and as a surgical knife.

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1573-2630

consensual reaction ; corneal autofluorescence ; corneal epithelial permeability ; corneal metabolism ; extracapsular lens extraction ; fluorophotometry

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose: The aim of this study was the assessment of possible changes in corneal metabolism and epithelial barrier function after an extracapsular lens extraction with artificial lens implantation. Methods: Ten patients without any eye medication were selected out of 140 patients attending for extracapsular lens extraction with lens implantation at the university hospital. Corneal metabolism was evaluated by fluorophotometric measurement of corneal autofluorescence. The corneal fluorescence values were corrected for interference by the fluorescence of the ocular lens. Corneal epithelial barrier function was evaluated by determination of corneal epithelial permeability. The permeability was calculated from the fluorescein penetration into the cornea after application of an eye bath containing fluorescein. Operated and fellow eyes were investigated 1 week before and 3–4 weeks after the operation. Results: The corneal autofluorescence of the operated eye decreased significantly after surgery (mean decrease: 14%, Wilcoxon paired-sample test: P = 0.038). The corneal epithelial permeability of both eyes increased after surgery above the normal range of healthy controls (mean increase operated eye: 34%, P = 0.015, fellow eye: 32%, P = 0.15). Both corneal autofluorescence and epithelial permeability returned to normal values after one year. Conclusions: The lower corneal autofluorescence in the operated eye after surgery indicates a lower corneal metabolism which may be due to surgery. The increased epithelial permeability of both eyes implies a temporary impairment of the corneal barrier function. The interaction with the fellow eye indicates a consensual reaction which may attributed to damage to the neural system by the surgery.

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1573-2630

fundus flavimaculatus ; myopia ; Stargardt's disease

Springer Online Journal Archives 1860-2000

Medicine

Abstract An unusual asymmetric pattern of fundus flavimaculatus was observed in a unilateral myopic patient. Although electrophysiologic testing was similar for both eyes, fundus lesions were different and less pronounced in the myopic eye.

Electronic Resource

1573-2630

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1573-2630

branch retinal vein occlusion ; neovascularization ; vitreous haemorrhage

Springer Online Journal Archives 1860-2000

Medicine

Abstract Neovascularization in branch retinal vein occlusion usually develops 6–12 months after the onset of the disease, although some cases have been reported in which neovascularization and subsequent vitreous haemorrhage developed 2–3 years later. This is a report of nine cases of late appearance of vitreous haemorrhage due to branch retinal vein occlusion, which occurred 3–6 years after the initial onset of the disease. In two of these nine cases the vitreous haemorrhage was very profound and had to be managed by vitrectomy. We have studied the remaining seven cases, which had retinal ischaemia and optic disc or retinal neovascularization documented by fluorescein angiographic examination. Laser coagulation was applied in these seven cases, which resulted in considerable regression of the neovascularization and absorption of the vitreous haemorrhage. In one out of the seven cases recurrent vitreous haemorrhages appeared and it was finally treated by vitrectomy. Visual acuity improved in six of the seven cases. The follow-up period ranged from 12 to 48 months. The late appearance of the ischaemic type of branch retinal vein occlusion with neovascularization can be attributed to the change in character of the initially mild oedematous form of the disease. Partial posterior vitreous detachment and traction exerted at some later stage upon the neovascularization could be additional factors of the late appearance of vitreous haemorrhage. Patients with branch retinal vein occlusion should be followed up regularly over a long period of time in order to avoid late complications of the disease, such as vitreous haemorrhage following optic disc or retinal neovascularization.

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1573-2630

blindness ; burden of disease ; low vision ; prevalence ; trachoma ; visual impairment

Springer Online Journal Archives 1860-2000

Medicine

Abstract This paper summarizes primary epidemiologic studies of trachomatous blindness to develop age-/sex-/region-specific estimates of the global prevalence of trachomatous blindness and low vision. These studies are first examined for their validity and then employed to derive a ‘minimum’ prevalence of trachomatous visual impairment. This method yields a global total for 1990 of approximately 640,000 cases of trachomatous blindness, corresponding to a prevalence of 0.12/1,000 (lower and upper bounds, 0.10 to 0.14/1,000). When those with low vision due to trachoma are included, 1.5 million cases of visual impairment are estimated, corresponding to a prevalence of 0.28/1,000 (lower and upper bounds, 0.15 to 0.75/1,000). A second approach, labeled the ‘projected’ prevalence of trachomatous visual impairment, selects country-wide studies to derive representative regional prevalence values. A global total of 2,899,000 blind (‘projected’ prevalence of 0.55/1,000 with lower and upper bounds, 0.37 to 0.83/1,000) is estimated for 1990. With trachomatous low vision included, greater than 6.7 million individuals in 1990 have visual impairment from trachoma (‘projected’ prevalence of 1.28/1,000 with lower and upper bounds, 0.53 to 4.29/1,000). Analysis of the distribution of the global prevalence by age, gender, visual acuity and region provide direction for trachoma research and programme priorities. Attention is drawn to the limited studies and resulting wide variation in the estimates of trachomatous visual impairment prevalence as indicated by the lower and upper bound estimates. It is recommended that this epidemiologic uncertainty be reflected in global and regional estimates of trachomatous visual impairment prevalence in order to draw attention to how little is known and emphasize the need for further surveys. A second paper incorporates these findings in an assessment of the global burden of trachomatous visual impairment.

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1573-2630

corneal endothelium ; endotoxin ; field emission scanning electron microscopy ; intercellular adhesion molecule-1 ; leukocytes

Springer Online Journal Archives 1860-2000

Medicine

Abstract After stimulation with Salmonella typhimurium endotoxin, the intercellular adhesion molecule-1 (ICAM-1) was studied on the corneal endothelium and associated leukocytes in rats using immunoscanning electron microscopy. Two hundred μg of the endotoxin was injected in Lewis rats. The corneae were excised at 0-h and 16-h-postinjection time (n = 5, respectively). The corneae were prepared in hypothermic University of Wisconsin (UW) solution for immunoscanning electron microscopy. Histotopographical examination visualized ICAM-1 antigen on cytoplasmic processes of the corneal endothelium, arranged along microfolds, especially at the peaks. In the leukocytes, ICAM-1 was located primarily in morphologically non-specialized domains of the cell body surface, and only rarely scattered on the surface of microvillar projections. We concluded that the endotoxin stimulation can increase ICAM-1 in both corneal endothelium and associated leukocytes. Increased ICAM-1 may be an important factor for the leukocytes to form clustering and adhering to the corneal endothelium.

Electronic Resource

1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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