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Biomedical subjects

P S Soni

Publications and source records attributed to P S Soni.

10 recordsLinked to original sources
PubMed1991

Reliability and validity of videokeratoscopic measurements.

When a test surface or a cornea is carefully and properly positioned with respect to the Corneal Modeling System (CMS) videokeratoscope, measurements are highly repeatable, but the accuracy of the measurements is dependent on the shape of the surface. For spherical and toroidal surfaces, the CMS provides suitably accurate descriptions of the topography of the surface. For aspheric surfaces the CMS renders less accurate, but still clinically acceptable, topographic descriptions.

Cornea↗
PubMed1991

The management of keratoconus using the corneal modeling system and a piggyback system of contact lenses.

The purpose of this report is to describe the use of the Corneal Modeling System (CMS) in the quantitative evaluation of the front surface of a soft contact lens on a keratoconic cornea. The management of one eye of a single case is presented as an example. A keratoconic patient fitted with an RGP lens presented with the signs and symptoms of discomfort, reduced wearing time and recurrent corneal erosions. Corneal topography was evaluated utilizing the CMS. The patient was then fitted with a soft contact lens. Next the entire front surface of the contact lens-fitted eye was measured with the CMS. Utilizing those data a piggyback lens was designed. As a result of this fitting technique corneal integrity improved, wearability increased and discomfort dissipated.

Adult↗
PubMed1990

Gastroesophageal reflux scintigraphy with radioactive capsules--a new technique for detection and quantitation of reflux.

A new technique for performing quantitative gastroesophageal scintigraphy has been described. The method involves administration of radioactivity in capsule form into the stomach; the isotope is released after dissolution of the capsule. The mean time of onset of capsule breakage was 3.3 min (range 2-5 min) and complete dissolution occurred by 6.0 min (range 5-8 min). The appearance of isotope activity in the oesophagus by means of cine scintigraphy was quantified by PDP 11/34 computer (Gamma-11) in terms of percentage of gastroesophageal reflux (GER). In 15 healthy subjects, the percentage of reflux (mean +/- S.D.) in the lower, middle and upper oesophagus was found to be 1.25 +/- 0.67, 0.26 +/- 0.23 and 0.02 +/- 0.04 respectively. We have studied 52 patients using this technique, and results are encouraging.

Capsules↗
PubMed1988

Density and radioactivity distribution of respirable range human serum albumin aerosol.

Dry human serum albumin (HSA) aerosol in the respirable size range was generated using the BARC nebulizer. The aerosol was sampled using Lovelace Aerosol Particle Separator (LAPS) and the density of HSA was determined. Labelling of HSA with 99mTcO4- was done, both in HSA solution and with dry denatured HSA particles, to study the distribution of radioactivity in both cases. The results are discussed in the paper.

Isotope Labeling↗
PubMed1988

Extended wear contact lens movement under swimming pool conditions.

On site swimming pool studies have indicated that soft contact lenses adhere to the cornea when exposed to swimming pool water. It was the aim of this investigation to study, under controlled laboratory conditions, both the adherence of hydrophilic extended wear lenses and any changes in lens movement with exposure to swimming pool water. Normal saline and a hypotonic solution having a pH and osmolality identical to the pool water served as controls. Exposure to both swimming pool water and the hypotonic solution promptly caused both lenses to stop moving and adhere to the cornea. Notably, the instillation of normal saline also caused a dramatic decrease in lens movement for some subjects.

Adolescent↗
PubMed1988

Complications reported with hydrogel extended wear contact lenses.

We conducted a survey to evaluate the incidence of various complications associated with extended wear (EW) contact lenses. Of the 137 surveys sent out, 44 responded, 15 with data. The analysis indicates: (1) EW contact lens patients receive nonuniform care, evident from the fact that the EW follow-up to EW dispensing ratio varied between 1.6 and 16.75; (2) the incidence of epithelial microcysts, striae, and giant papillary conjunctivitis (GPC) was found to be considerably lower than that reported previously; (3) the incidence of "red-eye" response and corneal ulcers was calculated to be within the lower end of the range of previously reported research; and (4) there may be a seasonal variation in the incidence of GPC and red-eye response as indicated by an increase in both conditions during the month of March as compared to February.

Conjunctivitis, Allergic↗
PubMed1986

Feasibility of extended wear lens use in chlorinated swimming pools.

A group of 14 active swimmers was studied to evaluate corneal and conjunctival health immediately after extended wear contact lenses were worn in a chlorinated swimming pool. Two different lenses, a high (70%) and a low (38%) water content, were used for each subject in order to compare the corneal response to the high and low water content lenses. No significant difference in corneal and conjunctival response was found between the two lenses. Statistically significant differences were seen in corneal thickness and halo size between swimming with and without contact lenses. Corneal superficial erosion was of greater concern under both the control and test conditions, but this is believed to be due to unforeseen experimental design errors. The frequency of contact lens loss in this study was 3.57%. Hence, the conclusion that the rate of loss of hydrophilic lenses in a swimming situation is not the only concern in regard to lens wear during swimming, but there are other important factors such as lens adherence to the cornea and bacterial contamination of the lenses that need to be studied further.

Chlorine↗
PubMed1977

Applanation tonometer correlations.

The Goldmann, Mackay-Marg, and Non-contact tonometers were compared on 25 subjects to establish correlations between measurements of intraocular pressure by these instruments. Topical anesthetic was used for the Goldmann and Mackay-Marg readings only. Correlations were high: between the Goldmann and the Non-contact, +0.93; between the Mackay-Marg and the Non-contact, +0.81; and between the Goldmann and the Mackay-Marg, +0.87.

Adolescent↗