Michael Shimshoni

Factors affecting long term results of successfully treated amblyopia: initial visual acuity and type of amblyopia.

AIMS--The study aimed to assess the effect of initial visual acuity and type of amblyopia on the long term results of successfully treated amblyopia. METHODS--The visual acuity of 94 patients, who had been successfully treated for unilateral amblyopia by occlusion of the good eye and followed up to the age of 9 years, was examined 6.4 years, on average, after cessation of treatment. Patients were divided into two groups according to the depth of amblyopia before occlusion therapy was started: those with visual acuity between 20/60 and 20/100 and those with visual acuity of 20/100 or worse. RESULTS--Deterioration of visual acuity was observed in 42% of patients in the first group and in 63% of patients in the second group. Their average deterioration, as measured by the Snellen chart, was 0.58 and 1.54 lines, respectively. The results were also assessed by the division of patients into three groups according to the type of amblyopia: strabismic, strabismic anisometropic, and anisometropic. Deterioration of visual acuity occurred in 46%, 79%, and 36% of patients in these three groups, with an average deterioration on the Snellen chart of 0.70, 2.04, and 0.64 lines, respectively. CONCLUSION--It is concluded that low initial visual acuity and strabismic anisometropic amblyopia are risk factors for deterioration of visual acuity in the long term, following the successful earlier treatment of eyes with amblyopia.

Long-term follow-up of occlusion therapy in amblyopia.

OBJECTIVE To determine whether the results of occlusion therapy for amblyopia are maintained into adulthood. DESIGN Prospective, observational case series. PARTICIPANTS Fifty-four patients, who were successfully treated in childhood for unilateral amblyopia by occlusion, were followed up to the age of 9 years, were evaluated in 1984 for long-term results 6.4 years on average after cessation of treatment, and accepted our invitation for reevaluation in 1999. METHODS All patients were given a complete eye examination. The visual acuity (VA) was measured. RESULTS The average period of follow-up was 21.5 years (range, 17.2-25.1 years). The mean age at the most recent examination was 29.0 +/- 2.1 years (range, 25.1-34). At this examination, a best-corrected visual acuity (BCVA) of 20/40 or better was achieved by 72.3% of the patients. The mean BCVA was 20/35 (20/25-20/70) at the end of occlusion therapy, 20/45 (20/20-20/300) in 1984, and 20/34 (20/15-20/100) at the present examination. Relative to the results at the end of therapy, BCVA at the present examination was maintained or improved in 66.7% of the patients. Relative to 1984, the BCVA in 1999 was maintained or improved in 87% of the patients. MAIN OUTCOME MEASURE Visual acuity. CONCLUSION Comparative evaluation of BCVA at a long-term follow-up examination, performed 21.5 years on average after cessation of occlusion therapy, showed that VA was maintained or improved in two thirds of patients who had been successfully treated by occlusion for unilateral amblyopia in childhood.

Factors Affecting Long-Term Results of Successfully Treated Amblyopia: Age at Beginning of Treatment and Age at Cessation of Monitoring

The visual acuity of 104 patients who had previously been successfully treated for unilateral amblyopia by occlusion of the good eye was examined 6.4 years, on average, after cessation of treatment. Three age groups were defined, according to the age at which treatment was started: younger (2 to 5.5 years), middle (5.5 to 8 years) and older (above 8 years). In 55% of the patients, the long-term follow-up examination revealed deterioration of the visual acuity. In patients in whom amblyopia had been monitored at least up to the age of 9 years, the age at which treatment was started did not significantly affect the mean amount of deterioration or the mean visual acuity noted at the long-term follow-up examination.

Relationship between suicide and myocardial infarction with regard to changing physical environmental conditions

In recent years, the possible association of changes in mortality from cardiovascular disease and myocardial infarction (MI) and deaths related to violence and the suicide rate has been repeatedly discussed. This study examined the relationship between cosmic physical changes (solar, geomagnetic and other space activity parameters) and changes in the total number of in-hospital and MI-related deaths and deaths from suicide to determine if a relationship exists between the distribution of total and MI-related deaths with suicide over time; some differences in the serotonergic mechanisms involved in the pathogenesis of MI and suicide were also taken into account. All suicides (n=2359) registered in the State of Israel from 1981 to 1989 (108 months) were analysed and compared with the total number of deaths (n=15601) and deaths from MI (n=1573) in a large university hospital over 180 months (1974–1989). The following were the main features of the Results. (1) Monthly suicide rate was correlated with space proton flux (r=0.42,P=0.0001) and with geomagnetic activity (r=−0.22,P=0.03). (2) Total hospital and MI-related deaths were correlated with solar activity parameters (r=0.35,P<0.001) and radiowave propagation (r=0.52-0.44,P<0.001), an with proton flux (r=−0.3 to −0.26,P<0.01). (3) Monthly suicide distribution over 108 months was correlated with MI (r=−0.33,P=0.0005) and total hospital mortality (r=−0.22,P=0.024). (4) Gender differences were prominent. We conclude that the monthly distributions of suicides and deaths from MI are adversely related to many environmental physical parameters and negatively correlated with each other.

Hospital cardiovascular deaths and total distribution of deaths in 180 consecutive months with different cosmic physical activity : a correlative study (1974-1988)

The dynamics of total hospital deaths from different kinds of cardiovascular diseases in one 1000-bed hospital were compared with 10 monthly cosmic/solar and geomagnetic physical activity parameters. Data used were of 180 consecutive months; 15601 deaths including 5667 from cardiovascular diseases were included in this study. It was concluded that the number of monthly hospital deaths shows a highly significant correlation with monthly solar physical activity.

Characterization of the set of values f(n) = [ na], n = 1, 2, ...

Let @a > 1. Denoting by [x] the integer part of x, we give complete answers to the following two questions: (1). Find f(n) = [n@a] as a function of n for all positive integers n. (2). Characterize the set of all f(n). Our answers to both questions depend on a counting system based on the convergents of the simple continued fraction expansion of @a. If 1 = 1, [k@b] is obtained from [k@a] by adjoining a zero at the latters end if and only if @a = 12 (2-a+@?(a^2+4)), a any positive integer. Modified results hold when @a is rational.

Intraocular pressure fluctuations during regular hemodialysis and ultrafiltration

Abstract The effect of hemodialysis and of ultrafiltration on intraocular pressure (IOP) was studied in 30 non glaucomatous patients (58 eyes) with chronic renal failure. IOP and serum osmolality were measured before and after dialysis and every hour during the procedure. IOP showed a slight but non‐significant rise when measured after hemodialysis and a significant drop for ultrafiltration. Serum osmolality decreased significantly when measured after hemodialysis, but remained stable for ultrafiltration. The variations in IOP were found to be significantly correlated with changes in osmolality during hemodialysis.

Intraocular pressure (IOP) in relation to four levels of daily geomagnetic and extreme yearly solar activity

The link between geomagnetic field activity (GMA), solar activity and intraocular pressure (IOP) in healthy individuals was investigated. The IOP of 485 patients (970 eyes) was recorded over three nonconsecutive years (1979, 1986, 1989) which were characterized by maximal solar activity (1979, 1989) or minimal solar activity (1986). The measurements were also correlated with four categories of GMA activity: quiet (level I0), unsettled (II0), active (III0), and stormy (IV0). Participants were also differentiated by age and sex. We found that IOP was lowest on days of level IV0 (stormy) GMA. The drop in IOP concomitant with a decrease in GMA level was more significant during periods of low solar activity and in persons over 65 years of age. There was a trend towards higher IOP values on days of levels II0 and IV0 GMA in years of high solar activity. Differences between the sexes and among individuals younger than 65 years were not significant. Our results show an interesting aspect of environmental influence on the healthy population.

Long term effect of hypermetropic anisometropia on the visual acuity of treated amblyopic eyes

AIM To evaluate the effect of the extent of hypermetropic anisometropia on the long term visual acuity results in amblyopic eyes following their treatment by occlusion. METHODS The visual acuity of 86 patients, who had been treated for unilateral amblyopia by occlusion of the fellow eye and followed up at least to the age of 9 years, was examined 6.4 years, on average, after cessation of treatment. Patients were divided into two groups—those with a small amount of hypermetropic anisometropia, where the spherical equivalent difference between the eyes ranged between 0 and +1.50 dioptres, and those with a large amount of hypermetropic anisometropia, where the difference was +1.75 dioptres or greater. RESULTS Deterioration of visual acuity after cessation of occlusion treatment occurred in 51% of the patients in the group with a small amount of anisometropia and in 75% of the patients in the group with a large amount. At cessation of treatment, the average visual acuity in both groups was 20/40+. At the long term follow up examination, however, the average visual acuity was 20/40− and 20/70, respectively. This difference was statistically significant. CONCLUSIONS Hypermetropic anisometropia greater than 1.50 dioptres appears to be a risk factor for deterioration of visual acuity in the long term, following treatment of amblyopic eyes by occlusion of the fellow eye.

Theoretical amplitudes of body waves from a dislocation source in the earth III. P, S and surface reflections

Abstract Expressions are obtained for the ray-theoretical spectral amplitudes of body waves induced by a shear dislocation of arbitrary orientation and depth situated in a radially heterogeneous model of the earth. Account is taken of the azimuthal and colatitudinal radiation patterns of the source, the geometrical spreading, and the reflections and refractions at the free surface and at the mantle-core boundary. In this work spectral amplitudes are calculated for P, SH, SV, PP, PPP, PS, PSS, SP, SPP, SSH, SSSH, SSV, and SSSV. The results are presented in the form of tables for a source of strength U 0 d S = 10 15 cm 3 , where U 0 is the amount of the dislocation and d S is the fault area. Given the slip and dip angles of the source, the amplitudes of these surface reflections and direct phases can be obtained from these tables for all azimuths, for most of the epicentral distances at which a particular phase is observable, and for all the fourteen focal depths included in the Jeffreys-Bullen tables. It is found that the depth of the source has a strong effect on the amplitudes of the body wave signals.