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Biomedical subjects

M D Sarver

Publications and source records attributed to M D Sarver.

15 recordsLinked to original sources
PubMed1979

Corneal edema with several hard corneal contact lenses.

Five patients were each fitted with polymethylacrylate (PMMA), BP Flex, and Polycon corneal contact lenses of the same dimensions. Corneal edema was monitored with a slit-lamp biomicroscope and pachometer. Lenses were worn in a double-masked and random sequence for periods of 6 hr. Patients developed less corneal edema with Polycon lenses than with PMMA lenses. There was no significant difference in corneal edema with PMMA and BP Flex lenses. Those patients who developed little corneal edema with optimum-fitting PMMA lenses also developed little edema with the BP Flex and Polycon lenses. Steeper-fitting PMMA and BP Flex lenses produced more corneal edema than optimum-fitting lenses made of the same materials, while steeper-fitting Polycon lenses produced only slightly more edema than the optimum-fitting Polycon lenses.

Adult↗
PubMed1978

Corneal effects of high plus hydrogel lenses.

Five aphakic patients and five phakic patients were fitted with high plus Bausch & Lomb Soflenses. We evaluated corneal edema, staining, vertical striae, and corneal thickness before and after a 5-hr wearing period. The high plus lenses produced average corneal-thickness changes of 9.6% and 7.1% for the phakic and aphakic groups, respectively. Biomicroscope examination showed moderate amounts of vertical striae, epithelial staining, and corneal edema for both groups. The amounts of edema, staining, and striae were higher than when regular and thin minus lenses were worn. It is likely that the thickness of the high plus lenses reduces the oxygen supply to the corneal epithelium, causing relatively marked edema.

Adult↗
PubMed1978

Corneal edema with contact lenses under closed-eye conditions.

Subjects wore PMMA, CAB, and thin hydrogel contact lenses with their eyes closed for periods of 6 hr. The corneal edema that developed was evaluated by observing the amount of central circular clouding and by measuring the increase in central corneal thickness with a slit-lamp biomicroscope and pachometer. Central circular clouding was greater with the PMMA and CAB lenses than with the thin hydrogel lenses. Corneal thickness increased by different amounts for the three subjects, but the three lens types caused about the same increase in corneal thickness for a given subject.

Adult↗
PubMed1978

Stability of CAB contact lenses with hydration.

The effects of hydration on the base curve of CAB lenses were measured with a radiuscope. A significant amount of lens warpage and variability in curvature was detected in all lenses under conditions of continuous hydration. Thinner lenses flattened more than thicker lenses of the same power. Lenses of greater minus power flattened more than lenses of less minus power for a given lens thickenss. Plus power lenses were more stable than minus power lenses. Control lenses, stored dry, did not flatten or warp.

Absorption↗
PubMed1977

Results with the Bausch and Lomb F3 series Soflens contact lens.

We wanted to determine whether the Bausch and Lomb F3 series Soflens contact lens increases the number of patients who can successfully wear Soflenses. Thirty-two patients (64 eyes) who could not successfully wear 12.5-mm-diameter B, F, J, or N series Soflenses were fitted with the 13.6-mm-diameter F3 series lenses. For 40 of the 64 eyes, the F3 series lenses were successfully worn. Use of this lens series clearly increased the number of patients who could be fitted with Bausch and Lomb Soflens contact lenses. For many patients, this flatter, larger lens centered better and improved vision and comfort compared with the best-fitting Soflens of the 12.5-mm-diameter series.

Adult↗
PubMed1977

Patient responses to gas-permeable hard (Polycon) contact lenses.

Forty-six patients who were unable to wear polymethylmethacrylate (PMMA) contact lenses, owing mainly to corneal edema and associated symptoms, were fitted with gas-permeable hard Polycon lenses of the same dimensions. Thirty-one patients (67%) wore the POLYCON lenses successfully. Thirteen (28%) did not, because of discomfort. For 2 patients, the results were unknown. None of the 46 patients exhibited observable edema with the POLYCON lenses. For a group of 5 patients (10 eyes), mean corneal thickness change after 8 hr of lens wear was insignificant. Oxygen transmissibility of these lenses is approximately 5.0 X 10(-11) (cm2 X ml O2)/(sec X ml X mm Hg), a value less than that for hydrogel lenses which produce more edema. It is predicted that gas-permeable hard lenses will eventually replace PMMA lenses.

Adolescent↗
PubMed1977

Soft and hard contact lenses worn in combination.

Each of 5 subjects with normal corneas was fitted with a Bausch & Lomb F3-series Soflens contact lens and with an experimental F3-series ultrathin Soflens. A best-fit PMMA lens was worn in combination with each of the soft lenses. In addition, a best-fit CAB lens and a tight PMMA lens were separately worn in combination with the ultrathin soft lens. Each of 3 subjects with keratoconus was fitted with an ultrathin soft lens combined with a PMMA lens. For the normal corneas, the combination that produced the least corneal edema after 5 hr was an ultrathin soft lens with either a PPM or CAB lens of best fit. Two of the 3 keratoconic subjects were able to wear their contact lens combination for the 5-hr test period; corneal swelling was 1.7% and 5.3% For all subjects, acuity with a combination co ntact lens system was better than with a soft or hard lens alone.

Adult↗
PubMed1977

Patient responses to 13.6-mm diameter Bausch & Lomb thin Soflens contact lenses.

Responses were obtained from 12 subjects (24 eyes) who wore 2 types of 13.6-mm diameter Bausch & Lomb Soflens contact lenses-thin F 3 lenses and conventional-thickness F3 lenses. These responses were also compared with those of patients who had worn thin F lenses that were 12.5 mm in diameter. Fewer patients experienced discomfort or corneal changes with the thin F3 lenses than with the conventional ones. Lens diameter was also an important factor in improving the patients' responses. Only 35% of a different sample of 23 patients who had been fitted with 12.5-mm diameter thin F lenses had been able to wear them successfully, compared with 75% of those wearing the 13.6-mm diameter thin F3 lenses, even though the mean corneal thickening caused by the smaller lenses did not differ significantly from that caused by the smaller lenses did not differ significantly from that caused by the thin F3 lenses. Thin hydrogel lenses with diameters larger than 13.6 mm thus might produce an even better overall patient response while still causing minimal corneal edema.

Adult↗
PubMed1977

Patient response to thin hydrogel contact lenses.

This study was designed to evaluate the patient response to experimental Bausch & Lomb thin F series SOFLENSES. The center thickness of these lenses was 0.04-0.06mm compared to 0.14-0.16 mm for the conventional F series lenses. Eight of the twenty-three subjects fitted (35% of the patients, 39% of the eyes) were successful by the standard of Sarver, Harris and Polse. The principal reason for failure was discomfort, which was often associated with poor centration and arcuate staining. Neither vertical corneal striae nor significant corneal thickening were observed during the eight hour wearing periods. Lens handling was a major problem. During the eight weeks of the study 35% of lenses used were torn. Our results indicate that even though thin F series SOFLENSES cause less corneal edema than conventional F series SOFLENSES, the overall patient response to these thin lenses is less favorable than the response to conventional SOFLENSES. Further research with thin hydrogel lenses is needed to determine if the patient response can be improved by altering such lens parameters as diameter and/or curvature.

Adult↗
PubMed1976

Apical bearing and success with the Bausch and Lomb Soflens (polymacon) contact lens.

Thirty-three patients (63 eyes) were fitted with Bausch and Lomb soflens (polymacon) contact lenses. The initial lenses were selected with the mean posterior apical radius 0.45 mm flatter than the flat keratometer reading of the cornea (S.D. = +/-0.31 MM). Forty-eight eyes (76%) were successfully fitted and 15 eyes (25%) were unsuccessfully fitted. Among the successfully fitted eyes, 31 were fitted with the initial lens, 12 required steeper lenses, and 5 required flatter lenses. The final successfully fitted lenses were on the average 0.40 mm flatter (S.D. = +/-0.32 mm) than the flat keratometer reading of the cornea. The unsuccessfully fitted lenses were not significantly different than the successfully fitted lenses, being 0.47 mm flatter (S.D. = +/-O.32 mm) than the flat keratometer reading of the cornea. Although the central lens-cornea relationship is helpful in fitting the Soflens, the number of successful results are increased significantly by changing to a lens with different parameters when lens performance and patient response are not optimal.

Adolescent↗
PubMed1976

The visual Rx.

Explore the source record for details and available documents.

Contact Lenses, Hydrophilic↗
PubMed1975

Corneal edema and vertical striae accompanying the wearing of hydrogel lenses.

Changes in corneal thickness and the ocurrence of vertical striae were monitored on 27 patients who wore both the "F" and "N" series Bausch and Lomb Soflens-TM (polymacon) contact lenses. Changes in corneal thickness were observed with both lenses; however, the "N" series lens caused slightly more corneal swelling. Vertical striae occurred in about 50% of the patients and was correlated with the development of corneal edema. In most cases where significant corneal edema was measured, it was possible to observe the edema using the biomicroscope.

Adult↗
PubMed1975

Corneal curvature and refractive error changes associated with wearing hydrogel contact lenses.

To determine if there are corneal curvature and refractive error changes associated with hydrogel lens wear, 27 patients wearing F series Bausch & Lomb SOFLENS-TM contact lenses were examined regularly for nine months. During the first month of lens wear, a mean corneal steepening of 0.23 DK plus or minus 0.18 and an increase in with-the-rule toricity were found, which persisted during the following eight months of wear. A mean increase in myopia of 0.35 DS plus or minus .211 DS was found after nine months of lens wear for five randomly selected patients. This amount of change was statistically significant and was highly correlated with the observed corneal steepening. Their lenses were removed after nine months of lens wear. Both corneal changes and the increase in myopia persisted during the 14 days after lens removal. If long term studies with larger samples show similar results, the effect of hydrogel lenses on corneal curvature and refractive error will have to be considered in the decision to fit this type of lens.

Adult↗
PubMed1975

Corneal curvature and supplemental power effect of the Bausch and Lomb SOFLENS contact lens.

The supplemental power effect (SPE) of F series Bausch and Lomb SOFLENS (polymacon) Contact Lenses was determined for a sample of 54 eyes. The mean value was +0.34 D=S.D.+/-0.37 D, range zero to +1.00 D. A significant correlation was present between the SPE and the apical lens-cornea bearing relationship. (p less than 0.01). The results of this study provide refractive evidence that a central lens-cornea alignment is achieved when the posterior apical radius of the lens is about 0.5 mm flatter than the flat radius of the cornea, S.D.+/-0.35 D. This information is clinically useful in assessing the patient's visual response as well as the fit of the lens.

Adult↗