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[Clinical observation of astigmatism induced by corneal incision after phacoemulsification].

OBJECTIVE: To evaluate the changes of astigmatism induced by corneal incision after phacoemulsification. METHODS: Phacoemulsification was performed on 62 cases (78 eyes) without suture for a corneal incision. The changes of corneal astigmatism before and after operation in group A (incision at the superior nasal or superior temporal) and B (incision at the steepest corneal meridian) were compared. RESULTS: Three months after the operation, the surgical induced astigmatism was (0.83 plus minus 0.65) D and (0.72 plus minus 0.55) D in group A and B respectively. There was no significant difference, statistically (P > 0.05). The changes of corneal astigmatism were 0.11 D and 0.39 D in group A and B respectively, the difference being statistically significant (P < 0.05). CONCLUSION: Surgically induced astigmatism is very small after a corneal incision in phacoemulsification without a suture. If the incision is placed on the steepest meridian, the corneal astigmatism can be significantly reduced postoperatively.

Adolescent↗

[Eccentric therapeutic penetrating corneal transplantation].

OBJECTIVE: To study the effective ways to restore sight and control the postoperative corneal astigmatism in eccentric penetrating keratoplasty. METHODS: Marks were made on the meridian where the center of recipient bed was located, and at that meridian the distance between the external edge of recipient bed and the limbus (two point marking technique) was also marked. Afterward, the donor graft was cut down from a donor eye at the corresponding position and sutured on the recipient bed. This technique was performed on 23 cases with eccentric corneal ulcer and perforation, and they were followed up for 3 months to 2 years. RESULTS: The grafts of 18 eyes remained transparent. The visual acuities were obtained > 0.1 in 16 cases, > 0.4 in 6 cases. Among them, visual acuity of 1.0 was obtained in 2 cases. CONCLUSIONS: Two point marking technique can reduce the postoperative corneal astigmatism and obtain satisfactory visual acuity in eccentric penetrating keratoplasty. This technique is simple and easy to perform.

Adolescent↗

Manufacturer's recall of rapid assay kits based on false positive Cryptosporidium antigen tests--Wisconsin, 2001-2002.

The Wisconsin Division of Public Health and the Wisconsin State Laboratory of Hygiene (WSLH) reported that a recent cluster of cryptosporidiosis cases in a three-county area in southeastern Wisconsin was the result of false-positive tests. During December 1, 2001-February 1, 2002, approximately 30 cases of cryptosporidiosis were diagnosed at a laboratory in southeastern Wisconsin using the Becton, Dickinson, and Company (Franklin Lakes, New Jersey) ColorPAC Cryptosporidium/Giardia rapid assay (lot number 219370, expiration date 2002-06-05). Seventeen stool specimens, which were collected from 11 patients and tested positive by the rapid assay, were re-evaluated at WSLH. Six of these stool specimens were in EcoFix (Meridian Bioscience Inc., Cincinnati, Ohio), eight were in Cary-Blair transport media, and three were formalin fixed. All 17 specimens tested negative for Cryptosporidium at WSLH using the hot safranin stain and MeriFluor (Meridian Bioscience Inc., Cincinnati, Ohio) Cryptosporidium/Giardia direct fluorescent antibody kit with concentrated specimens.

Animals↗

[Structure of reciprocal connections in visual cortical areas 17 and 18 in cats].

Single cortical columns of areas 17, 18 in the cat were microiontophoretically injected with horseradish peroxidase. Spatial and laminar distributions of retrogradell labelled cells in both areas were investigated. Following injections in area 17 or in area 18 the labelled cells' region in area 17 was elongated (in a tangential plane) along the representation of visual field horizontal meridian. However the labelled cells' region in area 18 was elongated along the representation of vertical meridian. Such projection patterns appear to be common in these cortical areas throughout the central 10 degrees on various elevations (from -40 degrees to +10 degrees) of the visual field representation. Thus the spatial arrangement of intrinsic and extrinsic connections in each area coincides, at the same time in area 17 they are orthogonal to area 18. The following visual information exchange scheme may be suggested. Area 17 may supply the area 18 with more detailed information on the horizontal component of the visual image, and in the opposite direction the information on the vertical component of the same image may be supplied.

Animals↗

Intraocular distribution of 70-kDa dextran after subconjunctival injection in mice.

PURPOSE: To investigate the intraocular distribution kinetics of 70-kDa dextran after subconjunctival injection. METHODS: The right eye of 15 mice received a single subconjunctival injection of a 1.5-microL solution of 0.25% 70-kDa tetramethylrhodamine-dextran (TMR-D). The distribution of fluorescent labeling in eye sections was examined by fluorescence microscopy at 0.25, 1, 4, 24, or 72 hours after the injection. The brightness and homogeneity of fluorescence in the sclera, choroid, and retina were scored near the injection site, on the side of the globe opposite the injection site, and adjacent to the optic nerve head. Fluorescence intensity within the sclera and choroid adjacent to the optic nerve was assessed quantitatively by imaging densitometry. RESULTS: TMR-D readily diffused transsclerally and dispersed throughout a large portion of the sclera, uvea, and cornea. Shortly after the injection, homogenous fluorescence was observed in the sclera and choroid on the same meridian as that of the injection site. This fluorescence gradually decreased in intensity with distance from the injection site. At the opposite meridian, fluorescence in the choroid was more intense than in the adjacent sclera and could be traced up to the ciliary muscle. TMR-D was also observed in the retinal and optic nerve vessels. The intensity of scleral and choroidal fluorescence adjacent to the optic nerve reached a maxima at 1 hour, and then decreased slowly, with half-lives of approximately 16 and 100 hours, respectively. Visible fluorescence was maintained at least until 72 hours in the sclera, choroid, iris, and cornea. Specific fluorescent labeling was never found in the contralateral eyes. CONCLUSIONS: Macromolecular 70-kDa dextran can be readily delivered to the mouse retina and uveal tissues by subconjunctival injection through transscleral diffusion, local hematogenous spread, and possibly movement through the uveoscleral outflow pathway. Subconjunctival injection may be a useful approach for delivering macromolecules to the retina and uvea.

Animals↗

[Differential diagnosis of bitemporal paracentral visual fields defects in "low-tension glaucoma" and tumors of the pituitary gland (author's transl)].

A 46-year-old patient shows paracentral scotomas in the oblique meridians of the visual fields. Additionally there exists pathologically cupped, atrophical disks which lead to the tentative diagnosis of "low-tension glaucoma". As the scotomas are bitemporally located a tumor near the chiasm must be the cause for these field defects. During the operation a chromophobe adenoma of the pituitary gland was found in the patient. We pointed out that even arcuate scotomas which cross the vertical meridian of the visual field can be caused by an intra- or parasellar tumor. As Hoyt has shown in his investigations in animals one could suppose that these scotomas can be developed from direct compression of the chiasm.

Adenoma↗

Functional imaging of the mechanisms underlying the bilateral field advantage.

Visual stimulus comparisons across the vertical meridian are faster and more accurate than those restricted to a single hemifield (the bilateral field advantage). We set out to investigate the cerebral mechanisms underlying this effect using functional magnetic resonance imaging. Seven normal volunteers were presented pairs of shape stimuli bilaterally across the vertical meridian and unilaterally within a single hemifield. We found a network of additional areas activated in the unilateral condition over the bilateral condition which have been related to working memory in previous studies. The results suggest different processing strategies with different temporal characteristics in the bilateral and unilateral conditions, providing a novel explanation for the bilateral field advantage.

Adolescent↗

[Cyclotorsions].

Cyclotorsions are movements of cyclorotation of the eyes (in- or ex-cycloversions or vergences) and positions of cyclotorsion (in- or ex-cyclotorsion or cyclodeviation). Torsion is absent when the vertical meridian 0 traversing the cornea center is parallel to a plumbline. In a state of intorsion, the nasal end of the horizontal meridian is higher than the temporal part: the optic disk is lower than the fovea. Conversely the optic disk is higher in cases of excyclotorsion. Fundus observation is the only objective test in cases of torsion. Cyclodeviations are peripheral in nature (ex: SO palsy orbital strabismus) or linked to fixation (ex: congenital nystagmus, incyclo, and DTDs in infantile strabismus). All the facias and the orbits play a role in cyclorotations. The anterior fibers of the oblique muscles are responsible for torsion. Dissociated surgery and shift of the insertion follow. In a situation of cyclotorsion, the recti act differently (Weiss): the medial rectus becomes an elevator and is less an adducto, the superior rectus is less an elevator, etc. The consequences are alphabetic deviations, tilt of the coordimeter and synoptometer charts, displacement surgery of the recti insertions. Surgery of the facias must not be ignored. The study of torsions is currently evoluing.

Astigmatism↗

[Study on stroke syndrome of Chinese medicine and its relationship with blood hypercoagulative status and insulin resistance in diabetic ischemic stroke patients].

OBJECTIVE: To study the relationship of TCM Syndromes, involving Viscera Syndrome and involving Meridian Syndrome, with blood hypercoagulative state and insulin resistance in patients with diabetic ischemic stroke. METHODS: Insulin sensitivity index (ISI) could reflect the insulin resistance, and those reflecting blood hypercoagulative state parameters such as platelet agglutination test (PAgT), fibrinogen (FG), in vitro thrombus length (VTL) and activating partial thrombinogen time (APTT), were used to expound and prove the relationship with the stroke syndrome. RESULTS: The symptom scores, PAgT, VTL, FG levels in patients involved with Viscera Syndromes (including those of Wind Syndrome, Phlegm-Dampness Syndrome, Heat-Fire Syndrome and Yin-deficiency with Yang-excess Syndrome) were significantly higher than those in patients involved with Meridian Syndromes (P < 0.05 or P < 0.01), while the ISI level in the former was lower than that in the latter (P < 0.01). CONCLUSION: There is close relationship between blood hypercoagulative state, insulin resistance and TCM Stroke Syndromes in patients with diabetic ischemic stroke.

Aged↗

Refractive plasticity of the developing chick eye.

We have developed a lightweight plastic goggle with rigid contact lens inserts that can be applied to the eyes of newly hatched chicks to explore the range and accuracy of the developmental mechanism that responds to retinal defocus. Convex and concave lenses of 5, 10, 15, 20 and +30 D were applied to one eye on the day of hatching. The chick eye responds accurately to defocus between -10 and +15 D, although hyperopia develops more rapidly than myopia. Beyond this range there is first a levelling off of the response and then a decrease. The resulting refractive errors are caused mainly by increases and decreases in axial length, although high levels of hyperopia are associated with corneal flattening. If +/- 10 D defocusing lenses are applied nine days after hatching the resulting myopia and hyperopia are equal to about 80% of the inducing power. After one week of inducing myopia and hyperopia with +/- 10 D lenses, the inducing lenses were reversed. In this case, the refractive error did not reach the power of the second lens after another week of wear. Instead, astigmatism in varying amounts (0-12 D) was produced, being greater when reversal was from plus to minus. Finally, astigmatism can also be produced by applying 9 D toric inducing lenses on the day of hatching. The astigmatism produced varies from 2 to 6 D, and the most myopic meridian coincides with the power meridian of the inducing lens. This astigmatism appears to be primarily due to corneal toricity.(ABSTRACT TRUNCATED AT 250 WORDS)

Accommodation, Ocular↗

The retinal distribution of ganglion cells with crossed and uncrossed projections and the visual field representation in the opossum.

The retinal distribution of ganglion cells with crossed and uncrossed projections in the South American opossum, Didelphis marsupialis, was revealed by delivering HRP to one optic tract or to retinal targets of one hemisphere. The cells with uncrossed projections are restricted to the temporal retina, comprising 1/3 of the total retinal area, with a sharp transition at the naso-temporal boundary. Besides being distributed over the nasal 2/3 of the retina, cells with crossed projections are intermingled with those with uncrossed projections over the entire temporal retina. Quantitative analysis about the representation of the horizontal meridian on four specimens revealed that the maximum density of cells with uncrossed projections is on the average located at 3.2 mm (SD = 0.21), i.e. 34.8 deg, temporal to the optic disk, falling to 10% at 2.1 mm (SD = 0.14) or 22.8 deg. On the other hand, the peak for cells with crossed projections is more nasally placed at 1.8 mm (SD = 0.18), i.e. 19.6 deg. Between these two maxima, the site wherein the densities of cells with crossed and uncrossed projections are about equal is on the average about 2.7 mm (SD = 0.25) form the optic disk, i.e. 29.3 deg. This estimate supports the hypothesis that the retinal intersection of the vertical meridian lies within the region of split representation of crossed and uncrossed ganglion cells. In addition, it was observed that the opossum's retina has a large contingent of cells with uncrossed projections temporal to an eccentricity of 2.7 mm from the optic disk, where it represents roughly 2/3 of the ganglion cells. These data corroborate the relevance of the opossum as a non-primate model for visual work.

Animals↗

[Experimental-clinical substantiation of the use of micro-lamellar keratotomy combined with kerato-thermocoagulation in the correction of hypermetropia].

The article describes the methods for the correction of hypermetropia, i.e. micro-lamellar keratotomy (MLK) and MLK plus thermokeratocoagulation (MLKTKC). The experiment was made on 6 rabbits (12 eyes). Lamellar corneal incisions were implemented by ALK ACS system (USA) to a depth of 73-75% of the corneal thickness. Simultaneously, thermokeratocoagulation (TKC) to 80% of the corneal thickness was made in a part of animals in meridians 6, 8, 10 and 12 (an 8 mm optic zone and 3 to 4 coagulates in each meridian). Postoperatively, the keratometric data were evaluated in 1, 3 and 6 months. The corneal optic power went up, postoperatively, in the center by around 4.0 diopters in cases, when the common surgical technique was used, and it went up to 5.0-9.0 diopters, when the common technique was combined with TKC. A clinical approbation of the MLK and MLKTKC methods in adults with hypermetropia (44 operations, mean age 29.3 years) showed their efficiency and safety. The corneal refraction improvement ranged from 3.5 diopters to 7.5 diopters (mean 4.49 +/- 0.89 diopters). The developed method of the above surgeries (the diameter of the modeled optic zone is 5 mm, the lamellar depth incision is 73%) prevents the complications, which lead to irreversible changes of the cornea; besides, it makes it possible to preserve a sufficiently wide central optic zone with a present refraction. This study provided a foundation for the clinical use of the method in pediatric practice.

Adult↗

[Errors of monocular localization in strabismic amblyopia. Two-dimensional distortion].

Spatial distortions, i.e. spatial localization errors, and precision of localization were measured monocularly in the central visual field of 7 normal observers, 17 strabismic amblyopes and 2 anisometropic amblyopes. The task of the subjects was to construct circles of 2 degrees, 4 degrees and 6 degrees radius around a fixation point, using the dominant and the amblyopic eye in turn. Normal observers set distances on the vertical meridian smaller than distances on the horizontal meridian. Anisometropic amblyopes showed localization errors and variances similar to those of normal observers. The amblyopic eyes of strabismic observers with a large angle strabismus and deep amblyopia showed significant, individually different localization errors correlating with the depth of amblyopia. Strabismics with microstrabismus exhibited parallels between monocular localization and dichoptic retinal correspondence.

Amblyopia↗

[Experimental correction of irregular astigmatism in patients with keratoconus using diode laser thermal keratoplasty].

OBJECTIVE: To evaluate the potential of diode laser thermokeratoplasty (DTK) in the correction of irregular astigmatism in patients with keratoconus. GROUP AND METHODS: The coagulation of deep layers of cornea stroma was made on four eyes of four patients suffering from advanced keratoconus at the mean age of 31 years by means of the infrared contact cw laser Prolaser Rodenstock 1.9 DTK. The aim of the treatment was to increase the curvature of cornea in flat meridians and to compensate flattening of cornea in steep meridians by way of forming traction strips between the contracted tissue of individual coagulation points. The changes on the cornea topography and changes of visual functions were determined. RESULTS: The diode laser keratoplasty is capable to induce sector increase of cornea curvature and thereby improve symmetry pictures of irregular astigmatism in keratoconus. For a definitive inclusion of DLK into the spectrum of clinically applicable procedures, other therapeutic studies are needed as well as larger groups with relatively homogeneous pre-operation pictures.

Adult↗

The effect of trabeculectomy on corneal topography.

Trabeculectomy is increasingly being performed earlier in the treatment of primary open-angle glaucoma (POAG). Surgically-induced alterations in corneal curvature resulting from filtering surgery may have a significant impact on patients, especially younger ones, whose vision may already be compromised by visual-field loss. Using data obtained by computer-assisted topographic analysis performed preoperatively and at 12 weeks postoperatively, we longitudinally studied the corneal surface changes induced by primary trabeculectomy in eight eyes undergoing surgery for POAG or normal-tension glaucoma. Additional data collected included refraction, keratometry, axial length, intraocular pressure, and pachometry. Five of eight eyes developed 1.50 to 2.50 diopters of steepening in the 90-degree meridian. One patient developed flattening in the 180-degree meridian without vertical steepening. Two patients had little change in the central optical zone. Of the six eyes with induced with-the-rule astigmatism, keratometry was less sensitive than topographic analysis in detecting the changes induced by trabeculectomy. Our data indicate that changes in corneal curvature are induced by filtering surgery, but may be undetectable without topographic analysis.

Astigmatism↗

[Effect of ocular accommodation on refractive components in children].

PURPOSE: To study the correlation between ocular accommodation and ametropia, especially myopia by analyzing the effect of accommodation on refractive components in children. METHODS: The anterior chamber depth (AD), lens thickness (LT), vitreous chamber length (VL) and ocular axial length (AL) were measured for 135 cases (270 eyes) of children before and after cycloplegia. The corneal shapes of 136 eyes selected from the 270 eyes were studied before and after cycloplegia by a computerized video keratoscope. RESULTS: AD increased (P < 0. 001) while both LT (P < 0. 001) and VL decreased (P < 0. 01) significantly after cycloplegia regardless of their refractive state. However, AL increased for hyperopic eyes (P = 0.027) and decreased for myopic eyes (P = 0.008) after cycloplegia. For hyperopic eyes, the major keratometer K1 increased (P = 0.025) while for myopic eyes, the major keratometer K1 (P = 0.039) and minor keratometer K2 (P = 0.003) decreased after cycloplegia. Similarly, mean corneal power of zones 3 mm (MD3), 5 mm (MD5) and 7 mm (MD7) decreased dramatically (P < 0.05) with myopic eyes after cycloplegia, while MD3 (P = 0.009) increased with hyperopic eyes. The mean refractive power of the lower half vertical meridian (LMD) is greater than that of upper half (UMD); and the mean refractive power of the lateral half of the horizontal (LaMD) is greater than that of the medial half (MMD). CONCLUSION: The ocular accommodation has a great influence on refractive components in children. It is not only the process by which the refractive power of the lens is increased. Furthermore, the lens itself moved forward relatively. There is asymmetry of the corneal surface within the same horizontal or vertical meridian.

Accommodation, Ocular↗

Left-right and Yin-Yang balance of biophoton emission from hands.

Yearlong measurements of biophotons from palm and back of hand of three healthy people were performed. The detection of biophoton was done with two photomultiplier tubes whose spectral range was from 300 nm to 650 nm. The measurement was done on a circular area of diameter 46 mm whose centers were at the acupuncture point Laogong (PC8) of a palm and the mid-point of a back, respectively. The emission rates from the dorsa showed strong seasonal dependence which is consistent with the active nature of Yang meridians, while the palm sides show less seasonal dependence as they belong to the passive Yin meridians. This could be quantified simply by the standard deviations from the yearly average: They were 47.6 counts per second (cps), 66.1 cps and 66.0 cps from the dorsa, and 23.8 cps, 29.7 cps and 30.4 cps from the palms of subject 1, 2 and 3, respectively. Biophoton emission revealed qualitative individual tendencies: The subjects 1 and 2 emitted more strongly from the left dorsa, while the subject 3 from the right dorsum. The left-right balance of biophoton emission was well kept for normal people, which is in contrast with the severe imbalance for some stroke patients. Thus biophoton measurement has a diagnostic potential that encourages more studies.

Acupuncture↗

[Transition of the doctrine from ancient to medieval China for embryo and fetus on each month during pregnancy period].

There are written some doctrines about growth image of embryo and fetus, hygiene for woman on each month during pregnancy period etc. in ancient Chinese medical book the Taichan Shu, which compiled over 2200 years ago. Following results were obtained by a study on the transition doctrines from that of Taichan Shu to those of medieval Chinese and Japanese medical books such as the Zhubing Yuanhou Lun, the Qianjin Fang and the Ishin Po. (1) Doctrines about growth and hygiene on embryo and fetus had been developed on each coming book from the contents of the Taichan Shu descent. Doctrines about hygiene were mainly for pregnant woman, and some methods of them were told by using figure image and the five elements theory in the part. (2) There could be found additional doctrines about meridian and internal organs theory in the Zhubing Yuanhou Lun, the Qianjin Fang and the Ishin Po. And those additional doctrines were made under the influence of the Maijing and the Suwen. New doctrines about hygiene for pregnant woman found in the Qianjin Fang and the Ishin Po also have relationships with meridian and internal organs theory. (3) Growing organs of embryo and fetus described in the Zhubing Yuanhou Lun and the Qianjin Fang correspond with the internal organs theory. Purpose of those descriptions is estimated to be equipped much more organs for embryo and fetus than those of the Taichan Chu.

Embryo, Mammalian↗