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Biomedical subjects

T Grant

Publications and source records attributed to T Grant.

At least 19 recordsLinked to original sources
PubMed1992

Comparative visual performance of three presbyopic contact lens corrections.

We compared the visual performance of a soft diffractive (DIFF) bifocal contact lens, a near center (CN) concentric bifocal design, and monovision (MV), using a comprehensive vision testing protocol. Fifteen presbyopic subjects who were successfully wearing DIFF bifocal contact lenses participated in the study. Of the three systems tested, MV provided best visual acuity at distance and near; less than one line of acuity was lost relative to best spectacle acuity under all lighting and contrast conditions, and there was less disturbance of a point source of light. Both bifocal corrections gave similar visual acuity performance, with more lines of acuity lost relative to spectacles at near compared to distance. However, the concentric bifocal induced more ghosting at near than the other two systems. Stereopsis was compromised at distance with MV correction, but all systems performed worse than spectacles at near. An understanding of the strengths and weaknesses of presbyopic contact lens options allows the clinician to improve management of the presbyope who wishes to wear contact lenses.

Contact Lenses, Hydrophilic↗
PubMed1992

Interest of presbyopes in contact lens correction and their success with monovision.

The presbyopic population is seen as a large potential source of contact lens wearers. The aims of this study were: (1) to estimate the percentage of presbyopes interested in contact lenses, (2) to ascertain the success of interested presbyopes with monovision correction, and (3) to determine the percentage willing to continue wearing monovision lenses after 1 month's trial. Seven practitioners in Sydney surveyed consecutive presbyopes attending their practices about their interest in contact lenses. Of the 1133 presbyopes surveyed, 314 (28%) were interested in trying monovision lenses. A total of 72 patients were subsequently fitted with monovision in high water content hydrogel form. After 1 month, 46 of these patients (64%) were still wearing the lenses, and 39 (54%) expressed willingness to continue with monovision correction. The major reasons for discontinuation from lens wear during the 1-month trial were inadequate vision and difficulty in lens handling.

Adult↗
PubMed1992

Twelve-month success rates with a hydrogel diffractive bifocal contact lens.

In this study we assessed success rates over 12 months with a hydrogel diffractive bifocal contact lens. A total of 108 presbyopes were fitted with lenses, and after 12 months 46% were still wearing the lenses. Subjects with previous presbyopic lens-wearing experience achieved greater success (58% of those fitted) than neophyte lens wearers (33% of those fitted, and 17% of all neophyte presbyopes initially expressing an interest in contact lenses before screening). More neophytes failed for nonvision-related reasons than experienced subjects (31% vs. 12% of those fitted). Consequently, when nonvision-related failures were excluded from the calculation of success rates, 59% of those fitted with lenses (49% of neophytes and 66% of experienced subjects) were still wearing the lenses at 12 months. Most discontinuations from lens wear occurred in the first month of the study, the major reason for discontinuation being poor near vision (blur and/or ghosting; 47% of discontinuations).

Aged↗
PubMed1992

Clinical performance of two opaque, tinted soft contact lenses.

Comfort, visual acuity, visual fields, daytime corneal edema and corneal staining were evaluated on 22 subjects wearing opaque tinted and non-opaque control hydrogel lenses. CooperVision Permaflex Mystique (38% polymacon) and Wesley-Jessen Durasoft 3 Colors (55% phemfilcon A) opaque lenses were compared to non-opaque lenses from the same manufacturers (CooperVision CV Classic and Wesley-Jessen Durasoft 3). Subjects were randomly assigned one type of opaque lens and one clear lens on each of two days, and two opaque lenses on another day. All lenses yielded similar results in terms of comfort, visual acuity, visual fields and corneal staining. The only visual problem with the opaque lenses was the reporting of "haziness" (usually peripheral) in 72 percent of Mystique and 59 percent of Durasoft 3 Colors trials. The greatest daytime corneal edema, 4.7 percent, occurred with the Mystique lens compared with 2.7 percent with CV Classic and 1.8 percent and 1.7 percent with the opaque and clear Durasoft 3 lenses respectively. These levels of edema were associated with a 40 percent incidence of striae with Mystique (17/43), 14 percent with the CV Classic (3/21 eyes), 5 percent with Durasoft 3 clear (1/22 eyes) and 2 percent with Durasoft 3 opaque lenses (1/44 eyes). Corneal swelling correlated with the measured Dk/L of the lenses. The Durasoft 3 Colors lens was the opaque tinted lens of choice based primarily on corneal physiology.

Adult↗
PubMed1990

In-office microwave disinfection of soft contact lenses.

We evaluated the effectiveness of an in-office microwave disinfection procedure which allowed for the disinfection of up to 40 soft contact lenses at one time. Ciba AOSept cases filled with sterile unpreserved saline were contaminated with one of six FDA test challenge microorganisms at a concentration of approximately 10(3) colony forming units per milliliter (CFU/ml). Twenty cases were placed on the rotating plate of a standard 2450 MHz 650 W microwave oven in a 10-cm diameter circle. The cases were exposed to high intensity microwave irradiation for periods of 0 to 15 min. None of the 6 microorganisms evaluated survived 2 min or longer of microwave exposure. Our findings indicated that microwave irradiation can be a convenient, rapid, and effective method of disinfecting a number of soft contact lenses at one time and thus adaptable as an in-office soft contact lens disinfection procedure.

Bacteria↗
PubMed1987

The value of regular replacement of low water content contact lenses for extended wear.

Adverse effects were evaluated in 48 myopic patients who wore low water content hydrogel lenses for an average of 48 +/- 19 weeks. Only one acute "red eye" occurred in the regular replacement group (2% of patients), whereas seven cases (15%) occurred in the non-replacement lens wearing eye. The major cause of clinical failure was giant papillary conjunctivitis (GPC), but the incidence was similar in both the replaced (15%) and non-replaced (15%) lens wearing eyes. These findings indicate that the acute red eye incidence can be reduced by regular replacement, that unilateral lens replacement does not reduce the incidence of GPC and that regularly replacing low water content lenses does not minimize the chronic corneal changes that occur during extended wear.

Adult↗
PubMed1984

Limb salvage for skeletal and soft tissue sarcomas. Multidisciplinary preoperative therapy.

One hundred eighty-three patients with malignant skeletal (83) or soft tissue sarcoma (100) were entered into the multimodality preoperative limb salvage protocol. Local recurrences were observed in 5 of 183 (2.7%). Six patients required amputation because of complications, and 13 patients died within 1 year from metastatic disease. There was no statistical difference in survival rates between a series of patients who had amputation and adjuvant therapy and patients treated by limb salvage and adjuvant therapy. Overall survival rates for patients with soft tissue sarcoma were 76%. Although the exact reason for the improved local control is not known, it is our belief that it is the result of the multidisciplinary therapy that destroys microscopic disease at the periphery of the primary tumor.

Adolescent↗
PubMed1984

Aggregation and unit formation in the perception of moving collinear lines.

The degree to which collinear lines are treated as a unit in resolving rotary motion in depth was investigated with the use of parallel projection to make direction of motion ambiguous. The proportion of time that the collinear lines appeared to rotate in the same direction was used as an index of their perceptual coherence. When the gap between the lines was small, there was strong grouping of the lines with respect to direction of motion as well as appearance of rigidity for the configuration. For larger gaps the grouping for direction of motion was maintained, but the lines appeared to have different axes of rotation leading to an appearance of nonrigidity. It is concluded that line elements can be aggregated for the resolution of certain properties without constituting a unit in any general sense.

Depth Perception↗
PubMed1978

Adjuvant therapy for osteosarcoma: preoperative and postoperative treatment.

Seventeen consecutive patients with osteogenic sarcoma participated in a prospective study to ascertain first, whether postoperative adjuvant chemotherapy or chemoimmunotherapy could reduce the incidence of distant metastases and second, whether in situ tumor cell destruction could be achieved with preoperative chemotherapy and radiation therapy. To date 14 of 17 patients (85%) are alive and free of disease for a median survival time of 11 months. Three patients developed recurrent disease, one with local recurrence in the tibia and two with pulmonary metastases. Limb salvage was attained in 12 patients by cadaver allografts and in one patient by radiation alone at 6 months.

Adolescent↗