Search Results - "International Ophthalmology"

1573-2630

scanning laser tomography ; normal collective ; normalised rim/disc area ratio

Springer Online Journal Archives 1860-2000

Medicine

Abstract The assessment of the cup of the optic disc depends, among other criteria, on the disc area. A small cup in a small optic disc can indicate an advanced glaucomatous lesion, on the other hand a large cup in a large optic disc can be normal. Therefore, an individual normalised rim/disc area ratio line together with the curves of 50th percentile and the 95th percentile of normal could help to better distinguish between glaucomatous and normal optic cups. The aim of our study was to calculate and to evaluate such a normalised rim/disc area ratio line. Heidelberg Retina Tomograph examinations of the optic nerve head of 100 randomly selected eyes of 100 normal subjects were evaluated. We calculated the disc area adjusted rim/disc area ratio in sectors of 10 degree. The 95th percentile and the 50th percentile of each of the 36 sectors were calculated. Based on these normal percentile lines it was possible to display an individual normalised rim/disc area ratio line in the topographic images of an individual optic disc examination. Here we demonstrated examples of a normal optic disc, optic nerve heads with moderate and advanced lesions and a small optic disc with glaucomatous damage. We present a new display mode of the results of Heidelberg Retina Tomograph optic nerve head examination, which may be helpful for an easy and reliable assessment of glaucomatous optic nerve head damage only looking at topographic images.

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1573-2630

Choroidal neovascularization ; diode laser

Springer Online Journal Archives 1860-2000

Medicine

Abstract Background. Krypton or argon laser treatment of choroidal neovascularization (CNV) has been shown to be effective in reducing the incidence of severe visual loss. The usefulness of diode laser in the treatment of many chorioretinal disorders is currently under evaluation. Methods. Our study involved 42 eyes of 41 patients affected with CNV which were treated with a near infrared diode laser. Results. The mean follow-up was 10.12 months. Visual acuity improved in 12 eyes (28.6%), did not change in 17 eyes (40.5%) and worsened in 13 eyes (30.2%). Mean visual acuity before treatment was 0.23 and 0.21 after treatment. Recurrent CNV was seen in 13 eyes. In a subgroup of 24 well-defined juxtafoveal or extrafoveal CNVs which underwent direct photocoagulation visual acuity improved in 8 eyes (33.3%), was unchanged in 11 (45.8%) and worsened in 5 (20.9%). Five eyes showed recurrent CNV. Conclusions. Our results appear to support the use of diode laser in the treatment of CNVs. The deeper penetration into the choriocapillaris of the diode wavelength could be effective in blocking CNV by inducing a more extensive chorioretinal atrophy.

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1573-2630

clearance ; daunorubicin ; fluorophotometry ; proliferative vitreoretinopathy ; retinal detachment ; retinal toxicity

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose. Daunorubicin is a cytotoxic drug, which, in nontoxic doses, is effective in preventing cellular proliferation in experimental vitreoretinopathy. We studied dose and clearance of daunorubicin in various ocular tissues using fluorophotometry techniques. Methods. In vitro tests: The emission of fluorescence from the daunorubicin solution having a concentration range of 0.1 to 10 μg/mL in phosphate buffer was measured using an excitation wavelength range of 489 ± 10 nm. The emission of fluorescence was measured at 514 nm; the linearity of the response was determined using linear regression analysis. There is a fluorescence peak of daunorubicin at 485 nm. The validity and reproducibility of the method were examined. In vivo tests: The rabbits were randomized into three groups and daunorubicin concentrations of 4, 6, or 8 μg/mL were injected into the vitreous. Fluorophotometry scanning from the retina to the anterior chamber was performed with a commercially available fluorophotometer at various times up to 48 hours after injection to quantify fluorescence emission of daunorubicin. Results. The standard curve of fluorescence versus concentration of daunorubicin was linear in the range of 0.1 to 8 μg/mL. It was sensitive up to 0.1 μg. The daunorubicin time concentration profile showed a dose response relationship over the 48-hour period studied. The half-life of daunorubicin in the vitreous was about 5 hours. Conclusion. We performed fluorophotometry using a fluorophotometer whose exciter emits light at 489 nm, which is very close to an absorption peak of daunorubicin. These two values are close enough to obviate the need for modifying the commercial fluorophotometer. Therefore the concentration of daunorubicin in the vitreous cavity can be measured noninvasively.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

automatic perimetry ; Octopus ; adaptive strategies ; scotoma search programs ; high resolution ; caeconometry

Springer Online Journal Archives 1860-2000

Medicine

Abstract Two adaptive perimetric strategies for the search and the analysis of scotomata have been developed and tested over the normal and pathologically disturbed blind spot area. Adaptive procedures automatically concentrate their search effort upon areas of pathological disturbance and avoid time loss used for declaring normal areas as such. Provided a first scan of low spatial resolution detects only one edge of the blind spot, spatial resolution increases and analyses the blind spot, returning to low resolution as soon as the border of the blind spot is crossed and normal sensitivity is again attained. Two adaptive strategies are described. One reduces examination duration to 1/2, the other to about 1/3 when compared to a similar non adaptive high resolution strategy. Only in the latter this time reduction has to be paid by some loss of information. The accuracy of the threshold determination method described is limited whereas spatial precision is high. Hence a more accurate threshold determination technique has to be added if the postulate of great threshold accuracy is to be fulfilled.

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1573-2630

neovascularization ; retina ; iris ; optic disc

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

implant lens power ; emmetropizing implant lens ; iseikonizing implant lens

Springer Online Journal Archives 1860-2000

Medicine

Abstract The purpose of the paper is to describe a simplified mathematical scheme to calculate both the power of the emmetropizing lens implant, and the aniseikonia resulting from this lens, and the iseikonizing lens implant, with the spectacle refraction needed for emmetropization. The computations are correlated to the exact scheme as presented in a former paper and appear to fall within the limits of accuracy set by echographic biometry. The computations are performed by an inexpensive pocket calculator and are easily carried out. The combined yielding of the emmetropizing lens power, the aniseikonia produced by it, as well as the iseikonic lens brings an accurate prescription of a lens implant power into reach of every surgeon. A slightly modified program is available to perform similar calculations to estimate the power of a contact lens.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

CO2 laser ; tissue vaporization ; retina ; choroidal tumors

Springer Online Journal Archives 1860-2000

Medicine

Abstract The immediate and chronic effects of an intraocular carbon dioxide CO2 laser probe used for tissue vaporization were studied in cynomolgus monkeys' eyes. Acute lesions produced necrosis (from superficial to deep) of the retina and choroid, depending on the amount of energy used. Chronic lesions showed disorganization of the retina and choroid, with scar formation. Extensive tissue vaporization produced tractional retinal detachment in the chronic stage. Tractional detachment was prevented if the area of CO2 laser application was previously encircled with argon laser scars.

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1573-2630

lens ; colour ; brunescence ; grading ; age

Springer Online Journal Archives 1860-2000

Medicine

Abstract The nuclear colour of in vivo human lenses has been investigated by means of a colour matching technique, using ‘Munsell’ colour samples. Observations covered an extended age range, and included all degrees of nuclear pigmentation. A positive correlation was noted between increasing nuclear pigmentation and age. The colour matching data generated was used as a basis for establishing a system of nuclear brunescence grading. The system of grading consists of a Grade 0 for absence of brunescence, and Grade 1 to Grade 5 for increasing brunescence. The ‘Munsell’ notation for samples representing these grades are: Grade 0 (5GY 6/1), Grade 1 (5Y 7/4), Grade 2 (2.5Y 7/8), Grade 3 (7.5YR 6/8), Grade 4 (5YR 4/6), and Grade 5 (2.5YR 2.5/2). Assessments of both inter- and intra-observer variability in the use of the derived scale have shown the new colour grading system to be reliable. The measure is simple to use during biomicroscopic slit-lamp examination of the lens, and has the potential for routine clinical application as well as for use in clinical trials where detailed documentation of lens morphology is required. The new colour scale may be used either as an isolated measure, or as part of a battery of lens measures in the Oxford Clinical Cataract Classification and Grading system.

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1573-2630

proliferative vitreoretinopathy ; silicone oil ; fluorosilicone oil ; retinal detachment

Springer Online Journal Archives 1860-2000

Medicine

Abstract The effect of both regular silicone and fluorosilicone in preventing retinal detachment caused by experimental proliferative vitreoretinopathy was studied in rabbit eyes which received 250,000 fibroblasts after vitrectomy and lensectomy. In the control group, 14 out of 20 eyes which received fibroblasts had retinal detachments with disorganization of internal structures. In eyes receiving fibroblast and regular silicone, 4 out of 20 eyes had shallow retinal detachment. In the eyes receiving fibroblasts and fluorosilicone, 5 of 28 eyes had shallow retinal detachment. Our findings indicate that both regular silicone and fluorosilicone were effective in preventing retinal detachments caused by experimental proliferative vitreoretinopathy. There was no statistical difference between the two silicone oils.

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1573-2630

transvitreal pars plana sclerotomy ; contact Nd:YAG laser ; sapphire probe ; glaucoma

Springer Online Journal Archives 1860-2000

Medicine

Abstract Transvitreal pars plana sclerotomy using the contact Nd:YAG laser with a sapphire probe was performed on a group of rabbit eyes and compared with a similar procedure performed with a Ziegler knife. Although the intraocular pressure (IOP) was lowered in both groups of animals, the reduction was greater and more lasting in the group on which the Nd:YAG laser with sapphire probe was used. This technique may have application in cases with extensive peripheral anterior synechiae or where a vitrectomy as a combination procedure to clear ocular media is performed.

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1573-2630

Springer Online Journal Archives 1860-2000

Medicine

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1573-2630

proliferative vitreoretinopathy ; epiretinal membranes ; fibronectin ; vimentin ; macrophages

Springer Online Journal Archives 1860-2000

Medicine

Abstract Proliferative vitreoretinopathy is characterized by cellular proliferations in the periretinal space resulting in traction retinal detachment. Numerous cellular elements and connective tissue components have been identified by morphologic criteria as well as immunochemical techniques. In this study, we used the recently introduced APAAP (alkaline phosphatase - anti-alkaline phosphatase) immunostaining procedure to identify macrophages, T-lymphocytes, the structural proteins fibronectin, vimentin, and cytokeratin, and a proliferating cell antigen, in eleven human epiretinal membranes obtained during vitreoretinal surgery. Our results confirm that the pathologic processes in PVR are not immunologically mediated, but reveal the features of physiologic wound healing and scar formation. Posttraumatic PVR seems to be characterized by a severe initial inflammatory reaction as evidenced by the presence of numerous macrophages, whereas idiopathic PVR, as a complication of retinal detachment, may be caused by different mechanisms in the early pathogenesis.

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1573-2630

ophthalmia neonatorum ; sexually transmitted diseases ; Crédé's prophylaxis ; neonatal conjunctivitis

Springer Online Journal Archives 1860-2000

Medicine

Abstract In the 19th century, the incidence of neonatal conjunctivitis varied between 1 and 14% in Europe, and the disease was a main cause of blindness at that time. Since then the epidemiology of ophthalmia neonatorum (ON) has changed and Chlamydia trachomatis is more frequent than Neisseria gonorrhoeae. Both are still very common causes of ON in the developing world. ON can not be differentiated clinically as to the etiology, but Intracellular Gram Negative Diplococci (IGND) on a Gram stain of an eye smear has an excellent validity and further differentiation can be made using microbiological cultures. All cases of presumed gonococcal conjunctivitis must be treated with effective systemic antibiotics. Systemic treatment with penicillin can still be used in areas where the percentage of beta-lactamase producing strains of gonococci is very low. For other areas a single dose of ceftriaxone intramuscular combined with saline eye washes is the treatment of choice. Chlamydial ON necessitates also systemic treatment with erythromycin. Parents of infants with gonococcal or chlamydia ON also need to be examined and treated. Prevention of gonococcal and chlamydial disease can be done following 3 strategies: antenatal diagnosis and treatment of maternal infections or desinfection of the infants eyes at birth or adequate treatment of infants and parents as soon as a ON has been diagnosed. Crédé's eye prophylaxis with silver nitrate has become a controversial issue, because of concern about the occurrence of chemical conjunctivitis and its ineffectiveness against infections with C. trachomatis. Recent data however show that silver nitrate and tetracycline are highly effective in the prevention of gonococcal ophthalmia caused by multiresistant strains but are both not very useful to prevent chlamydial conjunctivitis.

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1573-2630

bromocriptine ; timolol ; intraocular pressure ; additive effect

Springer Online Journal Archives 1860-2000

Medicine

Abstract It has been confirmed that topically applied bromocriptine has a satisfactory intraocular pressure (IOP) lowering effect without serious ocular or systemic side effects. We compared the IOP lowering effects of 0.05% bromocriptine and 0.25% timolol and determined whether they have an additive effect in lowering IOP in normal volunteers. In a double-blind, randomised, prospective, single-dose study, we measured IOP in 24 ocular normotensive subjects before (baseline) and 2, 4 and 6 hours after topical instillation of the following drugs: timolol and bromocriptine alone (n : 14), timolol + bromocriptine, timolol + placebo, bromocriptine + placebo (n : 10). Both bromocriptine and timolol have a significant IOP lowering effect (p 〈 0.01) compared with the baseline value during the study period. There were no significant differences in IOP lowering effect between timolol and bromocriptine at 2 and 4 hours (p 〉 0.05), but timolol was more efficacious than bromocriptine at 6 hours (p 〈 0.05). An additive effect in lowering IOP was not found. Although timolol and bromocriptine have no additive effect in lowering IOP, topically applied bromocriptine may be used in the treatment of glaucoma.

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1573-2630

vitelliform macular dystrophy ; pattern distrophies ; retinal pigment epithelium

Springer Online Journal Archives 1860-2000

Medicine

Summary We report an unusual case of primary dystrophy of the retinal pigment epithelium (RPE) in which a vitelliform macular appearance was associated with reticular hyperpigmentation resembling the pattern dystrophies of the RPE. The entire evolution of the disease was observed and documented step-by-step during a 10-year follow-up. During the progressive change of the lesions morphologic characteristics of butterfly, reticular and macroreticular dystrophy as well as Best's macular dystrophy could be seen. Pathogenetic relationships between all of these dystrophies of the RPE can be supposed.

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1573-2630

nanophthalmus ; V-shaped unsutured sclerostomy ; uveal effusion

Springer Online Journal Archives 1860-2000

Medicine

Abstract Purpose: To evaluate the criteria of diagnosis and management of secondary glaucoma in young nanophthalmic patients. Methods: Considering the anatomic features and clinical characteristics, 22 eyes of 11 patients were identified as bilateral nanophthalmos. Intraocular pressures (IOP) were checked with Goldmann applanation or Keeler pulse-air 2000 tonometer, and Nd-Yag laser was used for iridotomies. Prophylactic V-shaped unsutured sclerectomies over the pars plana were combined with trabeculectomy, and Mitomycin C (MMC) in 0.2 mg/ml concentration was applied. Results: Among 22 eyes of bilateral nanophthalmic patients 8 eyes had secondary angle-closure glaucoma. Laser iridotomies were performed in 6 eyes. Laser iridotomy and supplemental medical therapy were sufficient in 4 out of 6 eyes. Mean IOP dropped from 26.4 to 14.5 mmHg in these patients. Due to continuous increase of IOP in the other patients, they underwent trabeculectomy with V-shaped sclerostomy and intraoperative MMC application. Mean IOP dropped from 39.3 mmHg to 19.3 mmHg. Postoperative uveal effusion or other major complications were not observed. Mean age of these patients was 14.6 years during treatment. Conclusion: Management of glaucoma in nanophthalmus is complicated. Initial treatment is medical. If it is insufficient, laser iridotomies and V-shaped sclerostomies with filtration surgery can be performed at any age.

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1573-2630

ibopamine ; dopamine ; glaucoma ; IOP

Springer Online Journal Archives 1860-2000

Medicine

Abstract Background: Topically administered 2% ibopamine (a dopaminergic agonist) induces a transitory ocular hypertension in 92% of patients with primary open-angle glaucoma and in 52% of patients with normal tension glaucoma. In normal eyes, ibopamine has no effect on IOP. Purpose: The aim of the present study was to verify, by means of fluorophotometric techniques, which hydrodynamic changes could be induced in normal and glaucomatous eyes, stimulating the Dl receptor with 2% ibopamine administered topically. In addiction, we wanted to evaluate if ibopamine could modify IOP before and after an experimentally induced outflow system impairment in rabbits. Methods: In study 1 we performed a measurement of aqueous humor flow in 6 healthy volunteers and in 6 glaucomatous patients, before and after 2% ibopamine administration. In study 2 the alteration of outflow pathways was induced by means of Laminaria Digitata in 10 rabbits. Results: After 2% ibopamine administration we found a significant increase in aqueous humor production, both in glaucomatous (P = 0.035) and normal eyes (P = 0.004). In rabbits, we found no significant change in IOP at basal conditions. After experimentally induced outflow system impairment by laminaria, we observed a marked increase in IOP (+ 13.5 mmHg SD 7.2; P 〈 = 0.001) following ibopamine administration. Conclusions: These experimental data have a diagnostic value in glaucoma, since they show how an intraocular hypertensive response due to ibopamine in normotensive eyes is a sign of initial outflow impairment. Moreover, the possibility to increase the aqueous humor production sets new trends in the treatment of post surgical ocular hypotony.

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