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Biomedical subjects

S Weinacht

Publications and source records attributed to S Weinacht.

6 recordsLinked to original sources
PubMed1999

Visual development in preterm and full-term infants: a prospective masked study.

PURPOSE: To compare development of visual acuity and binocular vision in preterm and full-term infants in a prospective study that used testers masked to subject's gestational age. METHODS: Seventy-nine healthy full-term infants, mean gestational age 40 weeks, and 18 low-risk preterm infants, mean gestational age 33 weeks, were examined biweekly between the 44th and 54th weeks of postmenstrual age. Ocular alignment, convergence, fusion, grating acuity, and onset of optokinetic nystagmus (OKN) were assessed at each examination. RESULTS: The mean postnatal ages of onset of ocular alignment, convergence, fusion, grating acuity to 1.6 cycles per degree, and OKN from temporal to nasal and nasal to temporal were, respectively, 5, 7, 7, 11, 6, and 9 weeks for the full-term and 12, 13, 14, 18, 13, and 16 weeks for the preterm infants. The mean postmenstrual ages of onset for the corresponding parameters were 46, 48, 48, 51, 46, and 50 weeks for full-term and 46, 47, 48, 52, 47, and 49 weeks for preterm infants. The onset of all parameters was earlier in full-term infants than in preterm infants of the same postnatal age (P < or = 0.0001). However, no differences were found when the parameters were compared at postmenstrual ages. CONCLUSIONS: Additional visual experience of preterm infants does not influence development of visual acuity or binocular vision during the first months of life as measured from the time of conception.

Aging↗
PubMed1998

The development of visual pursuit during the first months of life.

BACKGROUND: There are few previous investigations of smooth pursuit in infants. The aim of our study was to quantify visual pursuit in infants between 1 day and 16 weeks of age. METHODS: Eye movements of 97 healthy infants between 1 day and 16 weeks of age were recorded one to seven times with infrared photo-oculography. For stimulation of visual pursuit a square of 9.4 deg of visual angle with vertical gratings moved horizontally at a constant velocity of 7.5 deg/s. RESULTS: In the first 2 weeks of life, segments of smooth pursuit were measured with a maximum velocity of 7.93 deg/s, with a maximum gain of 1.06 and a maximal duration of 3.16 s. In sequential recordings no significant increases of velocity, gain or duration were found. However, the total time the subjects followed the stimulus with smooth plus saccadic pursuit increased significantly with age (from a median of 39.0% to a median of 61.5% of examination time). CONCLUSION: This study clearly demonstrates that smooth pursuit is already present in the first week of life. We found no significant increase in velocity, gain and duration of smooth pursuit segments in the first 16 weeks of life with our recording technique. However, the total pursuit time, reflecting attention, increased with age. The ocular machinery to drive pursuit appears to be in place at birth and seems not to be influenced by increased attention in the first months of life.

Aging↗
PubMed1996

Vertical Duane's retraction syndrome.

PURPOSE: We report three patients with a rare variant of Duane's retraction syndrome. METHODS: Eye movements were recorded by electro-oculography. One patient underwent electro-myography. RESULTS: All patients showed V-incommitance and twitch abduction on vertical saccades. Electromyography showed lateral rectus muscle firing activity during upgaze and downgaze. CONCLUSION: Our patients showed synergistic innervation between the lateral rectus muscle and ipsilateral vertical acting muscles documented by electromyography.

Adolescent↗
PubMed1996

[Observations of choroid pulsation].

BACKGROUND: While performing indocyanine-green (ICG) videoangiograms with the Rodenstock scanning laser ophthalmoscope (SLO), we got more and more aware of visible choroidal pulsation mainly during the inflow of ICG into the eye. We wanted to learn more about the frequency and the different forms of this phenomenon. MATERIAL AND METHODS: We examined 187 consecutive ICG angiographies retrospectively, which were performed with a Rodenstock SLO and stored by videotape. Most patients suffered from age-related macular degeneration and had a mean age of about 70 years. We defined 4 groups of different pulsatile dye inflow in the choroid, namely (group 1) the diffuse form, involving the whole macular region; (group 2) the local form, involving an area smaller than the fovea. In group 3 (mixed form) we found the pulsatile inflow diffuse initially, later on remained a local pulsation. In group 4 (special form) we noticed a localized pulsation of a longer duration (10-15 seconds) and of a special type, namely back and forth movements of dye in one or a few choroidal veins. In addition, we examined the presence of pulsation in the central retinal vein. RESULTS: In 173 of 187 angiograms we could examine the choroidal inflow in the macular region. We found in 94 of these 173 angiograms (or in 54%) choroidal pulsation. 84% of all cases were in group 1, 2 and 3. This probably physiological pulsation occurred mostly in the first few seconds after the inflow of the dye. After about 5 seconds it was normally not visible any more. In our group 4 we collected 16 out of 94 angiograms (or 17%). We could not find a correlation between the presence of a pulsation in the central vein and in the choroid. CONCLUSIONS: Choroidal pulsatile inflow of ICG is a frequent (most probably physiological) phenomenon. The localized pulsation found in several older patients with back and forth movements of dye in one or a few veins may be abnormal; it reflects phasic pressure changes in choroidal veins of low flow. We do not know yet if this phenomenon is of any diagnostic value. However, more studies of these interesting dynamic processes seem to be warranted.

Adult↗
PubMed1996

Adjunctive controlled topical application of tetracycline HCl in the treatment of localized persistent or recurrent periodontitis. Effects on clinical parameters and elastase-alpha1-proteinase inhibitor in gingival crevicular fluid.

35 patients receiving regular supportive periodontal therapy (SPT) and showing signs of localized persistent or recurrent periodontitis were enrolled in the study. Within 1 week after SPT, each patient had a tetracycline HCl loaded ethylene vinyl acetate co-polymer fiber placed into the periodontal pocket of 1 randomly selected tooth with persistent or recurrent periodontitis (test); the fiber was removed after 9.5+/-2.0 days. A non-adjacent tooth with persistent or recurrent periodontitis in a separate quadrant, which received no further treatment, served as a control. A total of 28 patients completed the 6-month study. Compared to control teeth, in test teeth at 6 months significantly (p<0.01) lower scores were found for gingival index, pocket probing depths, and PMN elastase-alpha1-proteinase inhibitor concentrations in gingival crevicular fluid. With the exception of plaque index scores, test teeth demonstrated significant reductions from baseline to 6 months in all parameters (p<0.05). Conversely, all parameter measurements in control teeth, except bleeding on probing, showed no significant difference between baseline and 6-month values. The results suggest that the use of controlled topical application of tetracycline HCl may improve periodontal health and reduce the risk of disease progression in localized persistent or recurrent periodontitis. Moreover, the effects of this application appear to be sustained for at least 6 months.

Administration, Topical↗