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PubMedDate not supplied

[Acupuncture reflexotherapy in the treatment of hypertension patients].

Acupuncture was used in a combination treatment of 110 patients with stage I to III hypertensive disease (HD). As far as acupuncture points are concerned we followed the lines laid down in the traditional Chinese medicine (TCM), with results of Ryodoraku investigation and those of auriculodiagnosis supplying a guide to the choice of points taking into account the type of hemodynamics. In our experience, redundancy with the meridian of the liver, unlike TCM notions about dominance under HD syndrome of fire and wind in the liver, was found to be the case in 40 percent of the patients while redundancy with meridians of the heart and pericardium was recordable in 97 and 84 percent of the cases respectively. The use of acupuncture points in the neck collar region and head and of antique points along the meridians of the heart and liver were shown to be effective treatment having a beneficial effect on cerebral circulation. Results of the clinical study suggest efficiency, expediency, and pathogenic value of acupuncture in the treatment of HD patients.

Acupuncture Points↗
PubMed2002

[Three-dimensionnal representation and descriptive geometry of the pure spherical and pure cylindrical profiles of Excimer photoablation].

PURPOSE: To analyze the theoretical shape of the lenticules of corneal tissue ablated using Excimer laser for the correction of pure negative and positive spherical and cylindrical refractive errors, and to investigate the possible correlations between their spatial configuration and the clinical outcome for each procedure. METHODS: To obtain a theoretical three-dimensional representation of each ablated lenticule, we used software that performs boolean operations on three-dimensional virtual surfaces (Bryce 3D, Metacreation, Dublin, Ireland). The representation of the theoretical shape of the refractive lenticule etched by a given profile of ablation based on a paraxial model over a circular optical zone was obtained by performing appropriate Boolean operations between different preoperative and postoperative surfaces or elements. These operations were repeated to obtain the representation of the theoretical additional lenticule corresponding to the volume of tissue ablated to blend any abrupt optical zone edges with a constant slope. RESULTS: The lenticule corresponding to the negative spherical treatment had its maximum thickness in its center and no thickness at its edge, thus inducing a natural blend with the peripheral untreated cornea. The lenticule corresponding to the positive spherical treatment had its maximal thickness at the junction between the optical and transition zones, which are both circular. The lenticule corresponding to the negative cylindrical treatment had its maximal thickness along the flatter initial meridian and an elliptical transition zone contour. The lenticule corresponding to the positive cylindrical treatment had its maximal thickness at the edge of the optical zone along the initial flatter meridian, and no thickness at the perpendicular principal meridian. The transition zone is also elliptical. CONCLUSION: The basic characteristics of the lenticule corresponding to the pure negative spherical treatment could explain the lesser degree of postoperative refractive regression than that one occurring after pure positive spherical treatment and pure positive and negative cylindrical treatments. The characteristics of the lenticules corresponding to the negative and positive cylindrical treatments may also account for the substantial spherocylindrical coupling and regression, respectively commonly observed after such treatments. The three-dimensional representation of the lenticules ablated for the correction of pure spherical and cylindrical refractive errors may help to better understand the outcome of these procedures aimed at reshaping the anterior surface of the cornea.

Algorithms↗
PubMed2002

[Retinal nerve fiber layer thickness in glaucomatous eyes. A comparative study between OCT and visual field].

PURPOSE: To investigate the retinal nerve fiber layer (RNFL) thickness in glaucomatous eyes using Optical Coherence Tomography (OCT). To compare the RNFL thickness with visual field damage (Humphrey field analyzer). MATERIAL AND METHODS: The mean RNFL thickness in glaucomatous eyes (n = 80) was compared with age-matched normal eyes (n = 40). Three circular scans were obtained for each eye using OCT (3.4 mm diameter). In each eye, average RNFL, 4 quadrants and 12 meridians were calculated and compared. The superior-inferior asymmetry of RNFL was studied. The average RNFL thickness was compared with mean deviation (MD) and mean standard deviation (MSD) of SITA 24-2 visual field program. RESULTS: Mean RNFL was significantly thinner in glaucomatous eyes than in normal eyes (p<0.001). The RNFL thickness was decrease in the 4 quadrants and 11 of 12 meridians studied in glaucomatous eyes (p<0.05). The superior-inferior asymmetry showed a significant difference in RNFL thickness at 30 degrees central meridian (p<0.05). Mean RNFL thickness was significantly associated with DM and DSM of visual field (p<0.001) in glaucomatous eyes. CONCLUSIONS: OCT revealed significant quantitative differences in RNFL thickness between glaucomatous and normal eyes. OCT showed a considerable measurements overlap between glaucomatous and normal eyes, which can limit the sensitivity and specificity of this instrument (Arch Soc Esp Oftalmol 2002; 77: 435-442).

Female↗
PubMed2003

Effect of acupressure on postoperative nausea and vomiting in laparoscopic cholecystectomy.

OBJECTIVE: To evaluate the effectiveness of acupressure applied at meridian P6 point for prevention of nausea and vomiting in patients undergoing laparoscopic cholecystectomy. METHODOLOGY: A randomized double blind study was performed in 50 ASA I and II patients scheduled for laparoscopic cholecystectomy. Patients were divided into two groups; control and placebo. In the control group acupressure was applied at P6 point half an hour before surgery while in the placebo group the acupressure band was tied on meridian P6 point but the plastic bead was placed on the dosum of right forearm away from meridian P6 point. Patients were assessed for nausea and vomiting for six hours after surgery. Anaesthetic technique and postoperative analgesia were standardized for all patients. RESULTS: Results showed that the incidence of postoperative nausea and vomiting was 36% in the treatment group and 40% in placebo group, which is statistically insignificant. CONCLUSION: Application of acupressure at P6 point half an hour before induction of anaesthesia does not significantly alter the incidence of postoperative nausea and/or vomiting within 6 hours after surgery.

Acupressure↗
PubMedDate not supplied

[Possibilities of prophylaxis of the induced "suture" astigmatism in cataract extraction].

Due to a number of reasons, the traditional methods of cataract extraction, i.e. through 8-12 mm limbic incisions, are still widely used in the clinical practice. A frequent occurrence of a high postoperative astigmatism, even if the operation is successful, is the main shortcoming of different variations of the traditional method of cataract extraction. Possibilities of how to neutralize the induced "suture-like" corneal astigmatism were investigated in this study by using two methods: A. a modified technique of applying a continuous corneal Pirs' suture with elements of an accentuated impact in the projection of the horizontal meridian. B. Meridian keratorraphia--application, in the cornea, of an additional compensatory suture in the projection of the horizontal meridian. Studies were made in two groups of patients after extracapsular cataract extraction (ECE) with intraocular lens (IOL) implantation--a total of 30 patients, 30 eyes. The main group was divided into two subgroups--A and B--(10 patients and 10 eye in each) in accordance with a used method of compensating the induced astigmatism. 10 patients were in the control group. A comparative evaluation of changes of a degree of the original astigmatism, which occurred under the influence of the sealing suture, showed that the parameters of induced astigmatism in the control group essentially and reliably (p < 0.001) exceeded the similar parameters registered in both subgroups of the main group; finally, the efficiency of method B in respect to neutralizing the "suture" astigmatism out did the possibilities of method A (p < 0.01).

Astigmatism↗
PubMed1992

Assessment of physiologic statokinetic dissociation by automated perimetry.

The effects of age, stimulus size, meridian, and eccentricity on physiologic statokinetic dissociation were investigated in clinically normal subjects using the Humphrey field analyzer (HFA, model 640), an automated perimeter capable of both static and kinetic perimetry. The right eyes of 20 age-matched young and 20 age-matched elderly volunteers was examined along the 15 degrees and 195 degrees meridians with six Goldmann size I and five size III kinetic stimuli. These were chosen to produce a spread of discrete eccentricities. Kinetic sensitivity was determined seven times for each stimulus, and the mean stimulus locations were expressed in terms of their x and y coordinates. Static sensitivity for each stimulus size then was determined seven times at each of the corresponding locations using a custom threshold program. The area under each sensitivity gradient was determined using the trapezium rule. Group mean kinetic sensitivity was greater than group mean static sensitivity (P < 0.001), and this difference was largely independent of age, stimulus size, meridian, and eccentricity.

Adult↗
PubMed1992

[Aniseikonia of central serous chorioretinopathy].

Central serous chorioretinopathy (CRS) is one of the typical diseases that accompany micropsia. However very little is known about micropsia of CRS, because of the difficulty to measure "aniseikonia" in terms of micropsia. Aniseikonia in 65 cases of CRS was measured quantitatively by Awaya's New Aniseikonia Tests (NAT). The tests were performed at two different distances of 40 cm (visual angle: 6 degrees) and 20 cm (12 degrees) and under 4 meridians of the halfmoon on NAT, horizontal, 45 degrees, vertical and 135 degrees, respectively. The mean value of aniseikonia under each testing condition was as follows: 6 degrees horizontal -3.13%, 45 degrees -2.56%, vertical -2.13%, 135 degrees -2.57%, 12 degrees; horizontal -1.38%, 45 degrees -1.69%, vertical -1.84%, 135 degrees -1.50%. At 6 degrees aniseikonia is larger in the horizontal meridian than in the vertical with statistical significance (t-test, p less than 0.05), while at 12 degrees aniseikonia is smaller than at 6 degrees and shows no particular tendency in terms of meridian. The phenomenon observed at 6 degrees may be what is called "oriented metamorphopsia".

Adult↗
PubMedDate not supplied

Computer simulation of arcuate keratotomy for astigmatism.

BACKGROUND: The development of refractive corneal surgery involves numerous attempts to isolate the effect of individual factors on surgical outcome. Computer simulation of refractive keratotomy allows the surgeon to alter variables of the technique and to isolate the effect of specific factors independent of other factors, something that cannot easily be done in any of the currently available experimental models. METHODS: We used the finite element numerical method to construct a mathematical model of the eye. The model analyzed stress-strain relationships in the normal corneoscleral shell and after astigmatic surgery. The model made the following assumptions: an axisymmetric eye, an idealized aspheric anterior corneal surface, transversal isotropy of the cornea, nonlinear strain tensor for large displacements, and near incompressibility of the corneoscleral shell. The eye was assumed to be fixed at the level of the optic nerve. The model described the acute elastic response of the eye to corneal surgery. RESULTS: We analyzed the effect of paired transverse arcuate corneal incisions for the correction of astigmatism. We evaluated the following incision variables and their effect on change in curvature of the incised and unincised meridians: length (longer, more steepening of unincised meridian), distance from the center of the cornea (farther, less flattening of incised meridian), depth (deeper, more effect), and the initial amount of astigmatism (small effect). CONCLUSIONS: Our finite element computer model gives reasonably accurate information about the relative effects of different surgical variables, and demonstrates the feasibility of using nonlinear, anisotropic assumptions in the construction of such a computer model. Comparison of these computer-generated results to clinically achieved results may help refine the computer model.

Animals↗
PubMed1990

Prospective topographic analysis in peripheral arcuate keratotomy for astigmatism.

Delimited peripheral arcuate keratotomy was performed on five eyes of four patients with naturally-occurring astigmatism. Refraction, keratometry, and computer-assisted corneal topographic analysis were performed before and after the procedure. In some eyes, preoperative topographic analysis revealed steepening distributed symmetrically about the corneal apex; in three eyes the steepening was asymmetrically distributed about the corneal apex. In one eye, surgery in a single, steep hemi-meridian superior to the corneal apex flattened that steep hemi-meridian but did not appear to alter the topography of the inferior steep hemi-meridian. Refractive and keratometric astigmatism decreased in all eyes (mean reductions of 3.25 and 2.30 diopters, respectively), and all incisions healed without incident. Surgery extended beyond the zone of steepening in one eye, shifting the axis of astigmatism. A large, multicenter, randomized trial will be necessary to determine whether detailed preoperative topographic analysis can be used to improve the results of surgery for astigmatism.

Adult↗
PubMedDate not supplied

Quantitative descriptors of corneal shape derived from computer-assisted analysis of photokeratographs.

The goal of this retrospective study was to derive clinically useful quantitative measures of corneal shape from computer-assisted analyses of photokeratoscope photographs. Algorithms were developed to determine a new index of corneal symmetry, the Surface Asymmetry Index (SAI). The SAI correlated well with best spectacle-corrected visual acuity and may be useful clinically for predicting the level of spectacle-corrected visual acuity that could be expected based on the corneal surface topography in the otherwise normal eye of an individual patient. Algorithms were also developed to determine the centrally-weighted average corneal power and the power and location of the steepest and flattest corneal meridians. The average surface power and the power of the steepest meridian determined from the photokeratographs correlated well with values obtained using the keratometer in the retrospective series (correlation coefficient = 0.98 for the average surface power and 0.97 for the power of the steepest meridian).

Aged↗
PubMed1989

[Pupillographic perimetry using the "Octopus"].

The Octopus 2000 computerized perimeter (Interzeag, Schlieren, Switzerland) is combined with an infrared videopupillograph (Demel, Haan, FRG) which at the same time records the direct pupil light response and controls fixation. Digital processing of the pupil video image is performed at a rate of 25 cps. A transient oscilloscope display of the pupil surface after each light stimulus covers the subsequent 1000 ms, so that either pupillary light reflexes or the lack of a response can immediately be identified. An additional continuous penwriter printout shows light stimuli, pupil responses and the subject's responses. Thus, potential discrepancies between the pupil response and the subject's response are clearly revealed. The examination conditions slightly deviate from the standard ones used with the Octopus. Stimulus size is analogous to the target Goldmann/V, the stimulus duration 100 ms and the adaptive illumination 1 cd/m2. Pupil fatigue considerably exceeds visual fatigue. Therefore standard Octopus perimetric programs are inconvenient for pupilloperimetric purposes. A Sargon-based pupilloperimetric program determines pupillomotor increment thresholds at 12 stimulus locations throughout the visual field (20 degrees nasal, 0 degrees, 20 degrees and 40 degrees temporal/15 degrees above the 0 degrees meridian, 0 degrees meridian and 15 degrees below the 0 degrees meridian) while applying the normal Octopus strategy of threshold calculation. Instead of the patient's subjective responses, the examiner's assessment of pupil responses provides the basis for threshold determination by the Octopus program. The subjects are unaware of the mode of examination. Their rating of "seen" or "not seen" ist displayed together with the pupil responses, thus providing a hard copy as proof of malingering or of appropriate cooperation.

Computer Systems↗
PubMed1986

[Study of spatial function using the contrast sensitivity function. Cases of presbyopic subjects fitted with progressive glasses].

The spatial properties of the global visual system were measured on the basis of the contrast sensitivity function, in three presbyopic observers. Shape alterations of the contrast sensitivity curves were found depending on the experimental conditions: foveal vision, in far, intermediary and near vision, along central, 13 degrees nasal and 13 degrees temporal meridians (according to three parallels and three meridians), peripheral vision, in far and near vision, at 13 degrees and 26 degrees retinal eccentricities using the central or nasal part of the lens. The central meridian was found to be the most efficient part of the progressive lenses. These results strengthen the observations reported by ophthalmologists and progressive lens wearers.

Accommodation, Ocular↗
PubMed1979

Lacrimal lens effects in Bausch and Lomb Soflens contact lens wear.

The correlation between lacrimal lens power changes and changing posterior apical radii was examined for a sample of 20 eyes wearing Bausch and Lomb Soflens contact lenses. Power changes caused by in situ lens flexure were calculated for principal meridians and both calculated in situ contact lens powers and over-refraction corrections were subtracted from the patient's spectacle corrections to determine lacrimal lens powers in each meridian. A significant correlation (p less than 0.01) was found in the flatter meridians for B, F, J, and N series lenses. To support the validity of the study a correlation was done between K's calculated from refractions done over the Bausch and Lomb Soflens contact lenses and both the K's calculated from refractions done over PMMA diagnostic lenses and the K's as measured with the keratometer. There was a significant (p less than 0.01) correlation in both series, indicating that calculated K's can validate the presence and power of a lacrimal lens in soft (hydrogel) contact lens wear as well as in conventional contact lens wear. (A correlation between the K's as measured with the keratometer and the K's calculated from refractions done over PMMA diagnostic lenses were also significant (p less than 0.01).

Contact Lenses, Hydrophilic↗
PubMed1982

The distribution of the cells of origin of callosal projections in cat visual cortex.

The distribution of neurons projecting through the corpus callosum (callosal neurons) was examined in retinotopically defined areas of cat visual cortex. As many callosal neurons as possible were labeled in a single animal by surgically dividing the posterior two-thirds of the corpus callosum and exposing the cut ends of callosal axons to horseradish peroxidase. The distribution of callosal neurons within a visual field representation was related to standard electrophysiological maps as well as to recording sites marked by electrolytic lesions. Callosal neurons were found in every retinotopically defined cortical area. The portion of the visual field representation that contained callosal neurons increased progressively from the area 17/18 border to area 19, to areas 20 and 21, and to the lateral suprasylvian visual areas. In area 17, the portion of the visual field representation containing callosal neurons extended from the vertical meridian out to a maximum of 10 degrees azimuth. In the posteromedial lateral suprasylvian visual area, callosal neurons were present in a region extending from the vertical meridian representation out to a representation of 60 degrees azimuth. Most callosal neurons were medium to large pyramids at the border of layers III and IV. A few layer IV stellates were among the callosal neurons of areas 17 and 18. In area 19 and even more so in the lateral suprasylvian visual areas, callosal neurons included pyramidal and fusiform-shaped cells in layers V and VI. The laminar distributions of callosal neurons in areas 20 and 21 were similar to those of area 19 and the lateral suprasylvian visual areas. The widespread distribution of callosal neurons in areas 20 and 21 and in the lateral suprasylvian visual areas suggests that the regions of peripheral visual field representation in cat cortex, as well as the representations of the vertical meridian, have access to the opposite cerebral hemisphere. This finding is significant in light of demonstrations of the importance of some of these cortical areas in the interhemispheric transfer of visual learning.

Animals↗
PubMed1984

Effect of tissue fit on corneal shape after transplantation.

Postkeratoplasty astigmatism is now a major problem preventing visual recovery. Certain postoperative topographic characteristics are felt to be dictated by the fit of the donor corneal button in its recipient bed. Deficient tissue at the wound is predicted to contribute to the location of the steep meridian and excess tissue to the location of the flat meridian. In an eight-cat sample using our Fit Assessment Method and Photogrammetric Index Method, the authors tested the relationship between button fit in recipient bed and resulting corneal curvature at approximately 42, 161, and 289 postoperative days. Corneal symmetry improved between the first and second postoperative periods. Deficient tissue led to steepened curvature and ample tissue to flattened curvature in the first measurement period. When buttons fit poorly, deficient tissue led to steepness in the first postoperative period, but led to flattened curvature 90 deg away from the deficient tissue meridian in the second and third periods. The relationship between ample tissue and flattest postoperative curvature did not depend on the magnitude of button-fed disparity in any period. Corneal elasticity appeared to influence the way tissue disparity affected postoperative topography. Our findings support Troutman's balloon mode. When there was a large amount of uncompensated tissue disparity, the tissue deficiency exerted a force that shortened the translimbal chord. This produced both steepened curvature parallel to this chord soon after surgery and flattened curvature at 90 deg to the chord in the stable postoperative cornea.

Animals↗
PubMedDate not supplied

Induction of astigmatism by straight transverse corneal incisions, 45 degrees long, at different clear zones in human cadaver eyes.

BACKGROUND: Two of the major factors affecting the amount of astigmatism correction are the length of the transverse incision and its distance from the center of the cornea. Many nomograms used in clinical practice have been created by varying the length or clear zone diameter of the incisions. A simplification of this situation has been suggested by Thornton, who has theorized that straight transverse incisions, subtending 45 degrees of arc, have equal astigmatic corrective effect at different clear zones. Our study tested Thornton's theory in human donor eyes. METHODS: Ten eyes were tested at four clear zones: 5.0, 6.0, 7.0, and 8.0 mm. Paired straight transverse incisions, subtending an arc of 45 degrees (2.1 to 3.3 mm long), were centered on the 90-degree meridian. Preoperative keratometric readings at the 180- and 90-degree meridians were compared to the postoperative readings; the difference was the total astigmatism induced. We also calculated the coupling ratio. RESULTS: Student's t-tests comparing clear zones 6.0 and 7.0 mm revealed a statistical difference (p = .0085) in total astigmatic induction, greater for the 6.0-millimeter zone. The coupling ratio decreased as the clear zone diameter increased, presumably as a result of diminished flattening effect along the incised meridian. One-way analysis of variance indicated that the groups were different (p = .0001), and that the theory noted above was incorrect. CONCLUSIONS: The effect of transverse incisions subtending the same angular length, drops off dramatically with clear zones larger than 6.0 mm, contrary to the theory of Thornton. This effect may be due to reduction in coupling as the clear zone diameter increases, suggesting that the greatest efficacy is achieved for transverse incisions placed between 5.0- and 6.0-millimeter zones.

Astigmatism↗
PubMedDate not supplied

Tangent screen perimetry (continuing education credit).

1. Tangent screen perimetry evaluates the central 30 degrees field at 1 m. The test is done on each eye separately, with the opposite eye patched. Testing at 2 m expands the field defects to twice their 1-meter size so that only 12 degrees to 15 degrees of central field is evaluated. 2. Maintain constant monitoring of the patient's fixation throughout the entire testing procedure. Move the target from nonseeing to seeing areas. Move along the stitched meridians at a constant speed of 5 degrees per second. Do not test directly on the vertical or horizontal meridians. 3. Test the fields using the appropriate screening protocols. Consider the Armaly/Drance protocol for glaucoma and vertical meridian mapping for neurologic problems. To maintain consistency in visual field interpretation, use standard color coding to document the size of the targets.

Documentation↗
PubMed1993

European isolation and confinement study. Attention during isolation and confinement.

The aim of this study was to examine the effect of isolation and confinement on selective attention. The experiments were carried out on six specially selected male subjects. The subjects were isolated in a hyperbaric chamber complex at a low overpressure for a period of 28 days. Distribution of attention between two tasks, visual search and orientation of attention to symbolic and automatic cues were studied. The results showed that 4 weeks of isolation and confinement do not significantly modify visual search and the capacity to execute two tasks simultaneously. In the double task experiment there was a clear improvement of performance during isolation and the post-isolation period. However, the development of a remarkably large difference between subjects was found. Orientation of attention to automatic cues gave results comparable to those obtained under normal conditions. Valid trials (stimulus flash and cue in same box) were faster than both neutral (cue in all boxes) and invalid trials (stimulus flash and cue in different boxes). Orientation of attention to symbolic cues also produced this effect. However, the "meridian effect" (increased reaction time when the stimulus is in the opposite half of the visual field as cue), which is constantly observed under normal conditions, was absent during isolation. The absence of the meridian effect is interpreted as a change in the subject's strategy to allocate attention. It is proposed that the absence of the meridian effect indicates an initial deficit of attentional capacities during isolation and confinement.

Adult↗