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Biomedical subjects

O D Solomon

Publications and source records attributed to O D Solomon.

15 recordsLinked to original sources
PubMed1999

Corneal indentation during ultrasonic pachometry.

PURPOSE: This study attempted to determine whether the indentation of the cornea with an ultrasonic probe affects the corneal-thickness measurement. METHODS: A solid-tip ultrasonic transducer was mounted into the spring arm of a standard Goldmann Applanation Tonometer. Five human subjects were studied. The visual axis of each cornea was marked with a corneal marker, and the ultrasonic transducer was placed on the visual axis. Corneal-thickness measurements were made during five tension settings of the tonometer: 0, 10, 20, 40, and 80. The R-F signals were received by using a 475 Textronix oscilloscope, and the thicknesses were digitally measured. RESULTS: There was no trend for decreasing or increasing thickness measurements with increasing tension settings. CONCLUSION: Corneal-thickness measurements by ultrasonic pachometry are not significantly affected by corneal indentation with the ultrasonic probe.

Anthropometry↗
PubMed1996

Corneal stress test for extended wear.

PURPOSE: The relationship between overnight contact lens wear and infectious corneal ulcers has been widely reported. Corneal hypoxia during sleep with contact lenses is believed to be an important predisposing factor for infectious corneal ulcers. We designed a provocative test to identify corneas at risk for significant oxygen deprivation during extended wear. METHODS: We measured the baseline corneal thickness of 161 eyes (82 patients). Extended wear soft lenses were then fit and pachymetry was repeated after 1 night of extended wear. Patients were instructed to continue extended wear for 6 additional nights. RESULTS: Seventeen of 161 eyes could not continue extended wear for the full 7 nights. All failures were due to corneal decompensation. There were no failures in the group of 133 eyes with corneal swelling of 5% or less after 1 day of extended wear. All four eyes with swelling greater than 13% failed, while the failure rates for the 24 eyes with swelling between 6-13% was about 50%. The thicker hyperopic lenses produced the majority of failures. CONCLUSIONS: Measuring corneal swelling after 1 night of extended wear may identify those corneas at risk for significant oxygen deprivation during overnight contact lens wear. Corneal swelling of 5% or less seems to indicate that the cornea can tolerate 7 nights of extended wear (significant to P < 0.001).

Circadian Rhythm↗
PubMed1996

A 3-year prospective study of the clinical performance of daily disposable contact lenses compared with frequent replacement and conventional daily wear contact lenses.

PURPOSE: To determine the clinical performance of daily disposable contact lens wear compared to conventional daily wear contact lenses and frequent replacement contact lenses. METHODS: This 3-year prospective study was conducted in 12 U.S. practices. Of 338 eligible subjects enrolled (126 conventional daily wear, 144 frequent replacement, and 68 daily disposable), 229 subjects disposable group were compared with the conventional daily wear group and two sub-groups of frequent replacement subjects: (a) those with replacement at 2-weak intervals and (b) those with replacement at 1 or 3 months. RESULTS: Comparing the daily disposable and conventional daily wear groups, the daily disposable subjects were more likely to be asymptomatic, reported fewer symptoms of redness, cloudy vision and grittiness/dirty sensation, reported better vision and overall satisfaction, and had fewer lens surface deposits, complications, tarsal abnormalities, and unscheduled visits, while conventional daily wear subjects reported better lens handling. Comparing the daily disposable and frequent replacement (1/3 months) groups, daily disposable subjects reported fewer symptoms of foreign body sensation, redness, cloudy vision and grittiness/dirty sensation, reported better subjective vision, comfort and overall satisfaction, and has fewer lens surface deposits, complications, and tarsal abnormalities, while frequent replacement (1/3 months) subjects reported fewer dryness symptoms and better lens handling. Comparing the daily disposable and frequent replacement (2-weeks) groups, daily disposable subjects reported better subjective vision and overall satisfaction and had fewer lens surface deposits and tarsal abnormalities, while frequent replacement (2-weeks) subjects reported fewer photophobia symptoms. CONCLUSIONS: The results indicate that daily disposable wear may be the most trouble-free way of wearing contact lenses.

Adult↗
PubMed1994

Testing hypotheses for risk factors for contact lens-associated infectious keratitis in an animal model.

Various risk factors contributing to contact lens related infectious corneal ulcers were tested. These factors included the presence of infectious organisms, loss of corneal surface integrity, and corneal hypoxia. High concentrations of Pseudomonas bacteria were applied to rabbit corneas under the following conditions: normal, intact corneal surface; "mild" corneal hypoxia with extended-wear soft contact lens and eyes closed; "moderate" corneal hypoxia with daily wear soft contact lens and eyes closed; "severe" corneal hypoxia with daily wear aphakic soft contact lens and eyes closed; corneal abrasion and eyes open; corneal abrasion and eyes closed; corneal abrasion with soft contact lens and closed eyes. No infectious ulcers occurred in normal intact corneas. The frequency of infectious ulcers increased with increasing degrees of corneal swelling. No ulcers were found in corneas with a mean swelling of 10%, whereas a mean swelling of 20% resulted in ulcers in half the group, and a mean swelling of 43% resulted in ulcers in all eyes. The three groups of abraded corneas resulted in infectious ulcers at a 20 to 30% frequency. The presence of infectious organisms alone does not lead to infectious corneal ulcers in rabbits. Corneal abrasions are a risk factor for infectious ulcers, but moderate and severe degrees of hypoxia are more significant.

Animals↗
PubMed1993

Micropachometry.

Explore the source record for details and available documents.

Contact Lenses↗
PubMed1981

Surgical management of black ball hyphema with sodium hyaluronate.

A surgical technique for removing black ball hyphema in a pseudophakic patient is described. Three days after a total postoperative hyphema developed, a solution of sodium hyaluronate, Healon, was injected into the anterior chamber through a 160 degrees limbal cataract incision. Healon dissected the clotted blood off the underlying iris and intraocular lens, maintained the anterior chamber, and expressed the clot in toto out of the eye. Postoperatively the patient had no further bleeding, the intraocular pressure remained normal, the pseudophakos remained clear and well positioned, and the cornea remained clear.

Aged↗