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PubMed2006

[Evaluation of diffuse lamellar keratitis after LASIK with confocal microscopy].

OBJECTIVE: To investigate the clinical pathologic characteristics and the pathogenesis of diffuse lamellar keratitis (DLK) after laser in situ keratomileusis (LASIK). METHODS: On 30 patients with 39 eyes being diagnosed with DLK (grade I-grade IV) after LASIK, slit-lamp examinations were performed 1, 3, 5, 7 and 30 days postoperatively, and scanning slit confocal microscope in vivo were performed 3, 7 and 30 days postoperatively. RESULTS: Typical characteristics of grade I and grade II DLK by confocal microscope examination showed up at 3 days postoperatively. We found that the epithelium, the posterior stroma and the endothelium were normal. In the lamella in front of the incision, many round or oval-shaped cells with diameter of approximately 12 approximately 20 microm were detected. These cells had eccentric, highly reflective nuclei and less reflective intracellular structures. They were most likely to be mononuclear cells. These cells distributed diffusely or arranged in line shape. In the lamella, clusters and lines of small, highly reflective, irregular shaped cells 8 to 10 microm in diameter were seen. They were similar to granulocytes or lymphocytes. Seven days postoperatively, these cells almost disappeared. Grade III DLK appeared from 3 to 5 days postoperatively, with more dense infiltration and more highly reflective irregular shape materials in the lamella. Grade IV DLK appeared 5 to 7 days postoperatively. Anterior stroma structure became unclear, with highly reflective and folded corneal flap. Numerous highly reflective scarring formed late. CONCLUSIONS: DLK after LASIK is a inflammatory response in corneal lamella, its typical pathologic characteristic is inflammatory cells infiltration in the lamella. Several factors work together to cause DLK through endogenous and exogenous mechanisms.

Cornea↗
PubMed1993

Minimum views required to characterize cataracts when using the Scheimpflug camera.

We performed Scheimpflug slit lamp photography and computerized image analysis on 20 normal and 25 cataractous lenses using 18 slit images for each lens taken 10 degrees apart. The data gathered from the normals served as the reference to estimate the accuracy of representation of the cataracts by the least number of views (18 and less) using a Fourier interpolative algorithm. Using the error obtained with one view for the normals, our study suggests that the minimum number of views necessary for adequate characterization is two for cortical cataracts, two for nuclear cataracts, and six for posterior subcapsular cataracts. This information will be useful in longitudinal studies of cataracts, since most researchers presently use only one view, which may be adequate for normals but not for cataractous lenses. We found the Fourier interpolative algorithm useful in estimating the minimum views required for the current method of analyzing Scheimpflug images, and it can be easily applied to other similar images.

Algorithms↗
PubMed1980

The colour of the optic disc variation with location of illumination.

The variation of the colour of the optic disc was examined with a slit lamp and contact lens in 200 normal subjects simply by moving the image of the slit across the optic disc. This event was photographed in 15 subjects and colour densitometry was performed. The temporal part of the pale central excavation changes colour to red, when illuminated nasally and vice versa. The colour change could not be provoked in subjects with normal discs with flattening of the temporal disc sector. The whole neurorim reddens the whole way round when the slit hits the optic disc border, and dependent on fundus pigmentation slight redness was produced even when the slit was placed outside the disc in the neighbourhood of the border.

Adolescent↗
PubMed1999

A new video pachometer.

PURPOSE: Many studies of the cornea would benefit from a simple, objective method to measure corneal thickness. In this study, a new optical pachometer based on video and computer technology was designed and tested. METHODS: The slit beam of a photographic slit lamp was monitored with a video camera through one half of the biomicroscope. When the slit was properly aligned with the cornea, the operator triggered a flash, and one video frame that included the flash was captured. A custom software package detected epithelial and endothelial edges. Corneal thickness was calculated from the median corneal image width and image widths from similar measurements of contact lenses with known thicknesses. Corneal thickness was measured in 25 subjects by using this new instrument and was compared to thickness measured by using a conventional Haag-Streit pachometer. RESULTS: Corneal thickness in the 25 subjects measured on the new instrument was 512+/-20 microm and 515-/+21 microm in the right and left eyes, respectively (mean+/-SD). Thickness of the same corneas measured on the Haag-Streit pachometer was 530+/-22 microm and 534+/-20 microm in right and left eyes, respectively. The average SD of 10 consecutive measurements was 6.6 microm and 6.7 microm on the video and Haag-Streit pachometers, respectively (n = 50 corneas). CONCLUSIONS: The video pachometer provides a fast, objective means of measuring corneal thickness. It is simple to use and provides precision equal to that of the Haag-Streit pachometer.

Anthropometry↗
PubMedDate not supplied

Cataract classification.

Opacifications of the eye lens--generally defined as cataracts--develop in various different parts of the lens. Therefore, one has to differentiate the types of opacities. For epidemiological studies it is prerequisite to classify the cataracts according to their localization within the lens as well as to the size and intensity of the opacified area. Two approaches have been used in the past: 1) subjective methods of lens observation (based on slit lamp microscopy) and 2) objective methods with measurements of lens transparency or lens opacity respectively based on slit image documentation according to the Scheimpflug principle combined with the retroillumination technique. With ageing, the light transparency of the lens is subjected to considerable changes. Even without the formation of an opacity the transmission of the wavelengths in the UV-B/UV-A and the visible range is diminished. The single lens layers are affected by this phenomenon to different degrees. These changes which might also indicate an early stage of 'cataract formation' cannot be discerned by subjective methods. The densitometric image analysis of Scheimpflug slit images, however, allows the exact measurement of the light scatter in the single lens layers and enables the early recognition of disturbances in transparency which is of crucial importance particularly in cataract epidemiology. In view of our present knowledge the evaluation of risk factors which might be of importance in multifactorial cataract processes will hardly be possible by carrying out prevalence and/or incidence studies involving a single examination of the population. In this case follow-up studies (cohort studies) with repeated examinations are prerequisite. The 'objective methods' for classification alone are able to ensure the necessary reproducibility and the possibility to measure transparency changes in the lens before visible (and therefore subjectively recognizable) opacifications occurred. The methodical procedure with respect to an epidemiological study on the involvement of UV-B radiation in the processes of cataract formation in man requires the application of objective methods for cataract classification.

Adult↗
PubMed1979

[Vitrectomy under optical observation (author's transl)].

Slit lamp biomicroscopy without contact lens is achieved by upright Gullstrand fundus microscopy. The controlled angulation of the slit beam makes it possible to measure the position of objects in the vitreous cavity by correction of object and image points. This form of stereotaxis is used for guiding the laser beam in the fundus.

Fundus Oculi↗
PubMed1999

[Lacrimation disorders in workers chronically exposed to petroleum derivatives].

Lacrimal fluid plays a very significant role in maintaining proper functions of conjuctivas, cornea and eyelids. The fluid is secreted by the main lacrimal gland and additional glands. It produces the so called preocular lacrimal film. A number of clinical tests, such as Chirmer's tests I and II, break-up-time (BUT), lysozyme, and flow tests are used in quantitative and qualitative analyses, as well as in the determination of the lacrimal film stability. The aim of work was to utilize these in assessing the lacrimal secretion and the lacrimal film stability in workers chronically exposed to petroleum derivatives. Fifty three workers from departments of acetobenzene, benzene and butadiene, phenol and acetone, sewage waters, asphalt oxidas, polyethylene and polypropylene, were eligible for the study (group I). During previous examinations, acquired disorders in colour perception were diagnosed in all the subjects by means of the Mansuella-Fansworth 100-Hue test. The age range was 25 to 56 years, with a mediane of 44.1 years +/- 6.5. Mean duration of employment was 22 years (SD +/- 8.25). The control group (group II) was composed of 28 men aged between 24 and 60 years with a median of 42.7 years +/- 6.3, never employed under conditions of exposure to toxic chemicals. On the right eye of each subject Schirmer's test was performed after instilling into the conjunctival sac 1-2 drops of Alcain solution according to Whitcher. Five min following anesthesia of the conjunctival sac, a standardised belt of blotting-paper with colour dampness markers Vidisic (Dr Mann Pharma GMBH, Germany) was placed in the vicinity of the external angle of the eye. After 5 min the degree of the belt dampness was measured in millimetres. After 30 min the break-up-time test was performed on the left eye. Fluorescein was released to conjunctival sac from a sterile belt of blotting-paper (Haag-Strait Co.). A slit lamp with cobalt filter was used to calculate time (in sec) that elapsed between opening of the lid slit and the first symptom of breaking-up the lacrimal film. The results obtained were presented in the form of arithmetic means and standard deviation values +/- SD. Schirmer's test was 13.40 +/- 7.43 mm in group 1, and 22.54 +/- 8.25 mm in the control group, mean values differed significantly, p < 0.01. Lacrimal film break-up-time was 16.30 +/- 6.19 sec in group 1, and 31.48 +/- 7.96 sec in the control group, mean values differed significantly, p < 0.01. In persons chronically exposed to petroleum derivatives, statistically significant decrease in lacrimal secretion, as well as shortening of lacrimal film break-up-time were found when compared with the control group.

Adult↗
PubMed2002

Surgical removal of the internal limiting membrane for the treatment of a macular hole.

BACKGROUND: To evaluate the efficacy of internal limiting membrane (ILM) peeling in the treatment of a macular hole. METHODS: The ocular evaluation included Snellen visual acuity, a slit-lamp examination, indirect ophthalmoscopy, and contact lens biomicroscopy. The macular holes were confirmed using a Watzke-Allen slit beam test. Surgery consisted of a standard 3-port vitrectomy under local anesthesia. The vitreous was removed, and the macular ILM was peeled by creating a small opening and a tear in the ILM with a bent 22-gauge needle around the inner margin of the vascular arcade. The ILM flap was then grasped with end-gripping forceps, and a circular capsulorrhesis maneuver was initiated. Next, gas-fluid exchange and internal tamponade with 10% C3F8 were performed, followed by postoperative face-down positioning. RESULTS: Thirty-six eyes in 36 patients with idiopathic macular holes from stages 2 to 4 were included. The average follow-up time was 8.9 months. The holes were completely closed in 33 eyes (92%), and visual acuity was improved in 26 eyes (72%). Ten eyes were pseudophakic, 24 of the 26 phakic eyes had an increased density of the cataract after surgery, which was not detected in 2 cases. One of the patients had vitreous hemorrhage and hyphema; no retinal detachment or retinal tear was found in this study. CONCLUSION: Surgery for macular holes using ILM peeling has a high anatomical and functional success rate.

Adult↗
PubMed1977

Cataract in childhood: photograph methods in assessment.

The slit-lamp examination of the child's lens with cataract can yield useful prognostic signs, especially when this is supplemented by slit-image photography and measurement. A normal lens size for the subject's age is a good prognostic sign and is usually associated with a static cataract or with very slow deterioration in a developmental cataract. A small lens and absence of the anterior subcapsular clear zone are each associated with progressive cataract. Nuclear lamellar cataracts are shown to become smaller in diameter with time, which favours medical treatment with mydriasis.

Adolescent↗
PubMed2007

Objective measurement of backscattered light from the anterior and posterior cornea in vivo.

PURPOSE: To develop an objective and repeatable method of measuring corneal backscattered light from different depths of the cornea in vivo. METHODS: A modified slit lamp ("scatterometer"), with a video camera and synchronous white strobe light, was used to capture images of a 0.1-mm-wide slit beam through the cornea. Image analysis software was developed to measure backscatter from digitized high-magnification images of 82 normal corneas of 41 subjects. Forty eyes of 20 of the same subjects were examined again after 1 month. Mean backscatter from the anterior, middle, and posterior thirds of the cornea was compared between repeated measurements, and expressed in arbitrary scatter units (SU). RESULTS: Backscatter in the anterior third of the cornea was 451 +/- 42 SU (mean +/- SD, n = 82), from the middle third was 274 +/- 29 SU (n = 82), and from the posterior third was 242 +/- 28 SU (n = 82). The difference in backscatter measured a month apart was 5 +/- 27 SU (P = 0.34), 2 +/- 17 SU (P = 0.42), and 0 +/- 15 SU (P = 0.95) in the anterior, middle, and posterior thirds of the cornea, respectively. Minimum detectable differences between measurements were 12, 8, and 7 SU in the anterior, middle and posterior thirds, respectively (alpha = 0.05, beta = 0.20, n = 40). CONCLUSIONS: Backscatter can be measured at different depths of the cornea from high-magnification digitized images of a narrow slit beam through the cornea. The method is objective and repeatable and can be applied in prospective studies of deep and posterior lamellar keratoplasty.

Adult↗
PubMed1994

Optic disc measurement with the Zeiss four mirror contact lens.

A knowledge of the optic disc size may be of value when assessing the glaucoma suspect. The vertical diameter of the optic disc was measured using a Zeiss four mirror gonioscope and a 900 Haag-Streit slit-lamp in one eye of 39 patients, 32 with refractive errors within 3 dioptres of emmetropia. The disc was measured by projecting a slit beam of known height onto the image of the disc. A magnification factor for the contact lens was calculated from first principles and disc height recalculated. These measurements were compared with those obtained by photographic methods using the corrections suggested by Bengtsson and Krakau. In the analysis on the 32 eyes within 3 dioptres of emmetropia the best correlation with clinical measurements was obtained with correction 3 using spectacle refraction and keratometry (r = 0.8614). The contact lens measurement was within plus or minus 0.1 mm of the photographic measurement in 67% of cases and plus or minus 0.2 mm in all cases. This simple method is advocated for the routine assessment of optic disc size.

Contact Lenses↗
PubMed1997

Light-dependent corneal toxicity in streptozocin-treated rats.

PURPOSE: To find the role of nitric oxide (NO) in streptozocin-induced corneal toxicity in rats. METHODS: Sprague-Dawley rats were injected intraperitoneally with streptozotocin (65 mg/kg). For exposure to light, each rat cage was placed in a box surrounded with aluminum foil and illuminated for 6 hours per day with two 20-W fluorescent lamps at a distance of 50 cm. When not exposed to light, each cage was placed in a dark room. Some animals with and without light exposure also were treated with and without streptozotocin treatment. Control animals did not receive streptozotocin and were housed in a dark room 24 hours a day. Each group contained 15 rats. After 1, 3, 7, and 10 days of light exposure, concentrations of nitrite and nitrate, stable oxidation products of NO, were measured in the aqueous humor. Corneal changes also were examined by electron microscopy after 10 days. To examine specific NO-induced histopathologic changes, several rats were injected subconjunctivally with a balanced saline solution containing the NO-generating agent (S-nitroso-N-acetyl-D,L-penicillamine or (Z)-I-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1- ium-1, 2-diolate]). RESULTS: Concentrations of nitrite and nitrate were highest in the streptozocin-injected rats irradiated while under the fluorescent lamp. On the 10th day of the streptozotocin injection, the concentrations of nitrite and nitrate in streptozocin-treated rats irradiated while under the fluorescent lamp was almost two-and-a-half times greater than that of nontreated rats reared in the dark (111.37 +/- 7.47 microM, 45.43 +/- 3.91 microM, respectively). Slit-lamp biomicroscopy showed that the corneas swelled gradually and opacified by the third day in the irradiated streptozocin-injected group. The corneas became hazy to the point of indistinguishable detail structures by the 10th day, although those of the other rats were relatively clear at the same time. Histopathologically, ultrastructural changes included the remarkable swelling of intracytoplasmic organelles, including mitochondria, and denaturation of collagen fibril was shown in the streptozocin-injected-irradiated rats by the 10th day. The corneas injected with two NO-generating agents, S-nitroso-N-acetyl-D,L-penicillamine and (Z)-1-[2-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1- ium-1, 2-diolate, showed similar but more severe changes. CONCLUSIONS: Nitric oxide can cause damage to the mitochondria, the most important energy source of the cell, and induce ultrastructural damage to the corneal endothelium and fibroblast. The authors suggest that NO is associated with the development of corneal cytotoxicity and that NO production and subsequent cytotoxicity can be prevented by blocking to photoactivation.

Animals↗
PubMedDate not supplied

Seeing the invisible: the challenge of imaging vitreous.

Imaging the vitreous is an attempt to view what is by design invisible. The inability to adequately image vitreous hinders a more complete understanding of its normal structure and function and how these change in aging and disease. The combined use of more than one technique could provide better imaging for investigational and clinical purposes. Past and present imaging methodologies are summarized and research and clinical techniques that are currently in development for future applications, are discussed. Dark-field slit microscopy has been used to characterize vitreous anatomy, both within the vitreous body as well as at the vitreo-retinal interface. In addition to this methodology, slit-lamp biomicroscopy; direct, indirect, and scanning laser ophthalmoscopies; ultrasonography; optical coherence tomography; magnetic resonance and Raman spectroscopies; and dynamic light-scattering methodologies for noninvasive evaluation are presented. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography, but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy.

Eye Diseases↗
PubMed1978

Anterior segment fluorescein cineangiography.

We have developed a technique for performing anterior segment fluorescein cineangiography. Illumination is obtained with a halogen lamp of a standard slide projector that is fitted with a blue excitation filer. Cinematography occurs with a movie camera fitted with an absorption-type barrier filter and mounted to a photo slit lamp through a cineadapter. The technique has been successfully employed with animals, and it is anticipated that the light levels used are tolerable and safe for application with humans.

Animals↗
PubMed1989

The clinical grading of lens opacities.

A simple system has been developed for the clinical grading of the presence and severity of lens opacities. The densities of nuclear opacities as seen on clinical slit-lamp examination are graded in comparison with a set of standard photographs. The extent of cortical opacities seen on retroillumination is estimated in terms of segments involved. The dimensions of posterior subcapsular opacities are measured using the slit beam. Inter- and intraobserver trials were conducted with three observers. Twenty subjects were selected to provide a range of lens opacities. Weighted Kappa statistics for intraobserver agreement for these three types of opacities range between 0.58 and 1.00 and for interobserver agreement between 0.41 and 0.71. This clinical grading system shows good reproducibility and compares well with the grading of lens opacities in photographs. It should prove to be of considerable use in clinical and epidemiological studies of cataract.

Cataract↗
PubMed1980

Ultraviolet induced lysosome activity in corneal epithelium.

A 5,000 W Xe-Hg high pressure lamp and a double monochromator were used to produce a 3.3 nm half-bandpass ultraviolet radiation at 295 nm. Pigmented rabbit eyes were irradiated with radiant exposures from 140 Jm-2 to 10,000 Jm-2 and evaluated by slit-lamp biomicroscopy, light and electron microscopy. Corneal threshold (Hc) was 200 Jm-2 and lens threshold (HL) was 7,500 Jm-2. The most repeatable and reliable corneal response to these levels of UV was the development of corneal epithelial granules. Histological changes included a loss of superficial epithelial cells and selective UV induced autolysis of the wing cells. It is suggested that the biomicroscopically observed granules are the clinical manifestation of the secondary lysosomes revealed by light and electron microscopy. It is proposed that UV breaks down the primary lysosome membranes to release hydrolytic enzymes which in turn form the secondary lysosomes during autolysis. Extreme levels of radiant exposure at 295 nm result in indiscriminate destruction of all layers of the corneal epithelium, but the posterior cornea was spared.

Animals↗
PubMed2002

Imaging vitreous.

Purpose Imaging vitreous is a quest to view what is, by design, invisible. This treatise will review significant historical aspects, past and present imaging methodologies, and imaging techniques that are currently in development for future research and clinical applications. Methods Classic and modern histologic techniques, dark-field slit microscopy, clinical slit lamp biomicroscopy, standard and scanning laser ophthalmoscopy, ultrasonography, optical coherence tomography, magnetic resonance and raman spectroscopy, and dynamic light scattering methodologies are presented. Results The best available histologic techniques for imaging vitreous are those that avoid rapid dehydration of vitreous specimens. Dark-field slit microscopy enables in vitro imaging without dehydration or tissue fixatives. Optical coherence tomography enables better in vivo visualization of the vitreo-retinal interface than scanning laser ophthalmoscopy and ultrasonography but does not image the vitreous body. Dynamic light scattering can determine the average sizes of vitreous macromolecules within the vitreous body as well as possibly image the posterior vitreous cortex once detached, while Raman spectroscopy can detect altered vitreous molecules, such as glycated collagen and other proteins in diabetic vitreopathy. Conclusions The inability to adequately image vitreous hinders a more complete understanding of its normal structure and how this changes in aging and disease. The combined use of more than one technique could provide better imaging of vitreous for future investigational and clinical purposes.

Age Factors↗
PubMed1989

Testing a possible cocataractogenic potential of befunolol (Glauconex) with animal cataract models.

Befunolol was tested in an animal experiment with 2 cataract models of the Sprague-Dawley-rat. The treatment scheme was designed with 8 different treatment groups, such that befunolol could be tested single and in combination with one or two cataract models. Over the 6 weeks experimental period, slit lamp microscopy and Scheimpflug photography were employed as observation and documentation methods, extensive post-mortem biochemistry was carried out after sacrifice of the animals. Neither the in-vivo observation and documentation nor the biochemistry showed pronounced effects pointing to a cocataractogenic potential of the drug. Slit density enhancing effects were found in combining UV-B irradiation and befunolol treatment. This effect has also been found in other experiments with timolol.

Animals↗