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M Gemmill

Publications and source records attributed to M Gemmill.

7 recordsLinked to original sources
PubMed1991

The relationship of visual acuity, refractive error, and pupil size after radial keratotomy.

To better define the relationship between residual refractive error, uncorrected visual acuity, and pupil diameter, we compared 42 eyes that had an eight-incision radial keratotomy according to the Prospective Evaluation of Radial Keratotomy Study protocol with 42 matched control eyes. The parameters measured were best corrected visual acuity, uncorrected visual acuity, and the change in cycloplegic refraction with enlarging pupil diameter. The best corrected visual acuity was 20/16 in both the radial keratotomy and control groups, but the variability (SD) was higher in the radial keratotomy group. The average uncorrected visual acuity was 0.35 (35%) better in the radial keratotomy group, but the variability was 1.77 times higher. Change in refraction with dilation occurred in 9% of the controls and 36% of the radial keratotomy patients, indicating a significant difference (P = .002). The change in refraction with dilation in the eyes with radial keratotomy was almost equally split between a hyperopic change (17%) and a myopic change (18%), which was much different than in the control eyes, only 2% of which changed in a hyperopic direction and 7% in a myopic direction. The radial keratotomy patients with a myopic change had the best uncorrected visual acuity, indicating that positive spherical aberration yielded the best aspherical surface for uncorrected visual acuity.

Adult↗
PubMed1990

Inadequacy of a polyester (Mersilene) suture for the reduction of astigmatism after penetrating keratoplasty.

Through two prospective studies, we evaluated the use of polyester (Mersilene) sutures in penetrating keratoplasty. Study 1 was a randomized comparison of combined running and interrupted Mersilene and nylon sutures (n = 45). Study 2 was a case series of single running Mersilene with postoperative adjustment of suture tension to manage astigmatism (n = 23). Study 1 demonstrated that Mersilene interrupted sutures were 5.5 times more likely to have handling-related complications compared to nylon (P = 0.01); in addition, they were 3 times as likely to have tissue-related complications as nylon interrupted sutures (P = 0.16). Study 2 demonstrated a complication rate of 69% when Mersilene was used as a single adjustable running suture. At 6 months postoperatively, the median refractive astigmatism for the adjustable cases was 3.37 D (mean, 4.03 +/- 2.37 D). Eyes in Study 2 with significant suture-related complications were 2.85 times more likely to have greater than 4 D of refractive astigmatism than were eyes without suture-related complications. We concluded that Mersilene is an undesirable suture for use in penetrating keratoplasty.

Adult↗
PubMedDate not supplied

Complications of Mersilene sutures in penetrating keratoplasty.

BACKGROUND: After penetrating keratoplasty, many corneal surgeons adjust sutures to reduce astigmatism and then leave the sutures in place indefinitely. Nylon sutures can hydrolyze and break years after surgery. In a series of human penetrating keratoplasties, we studied the use of polyester (Mersilene) sutures that do not hydrolyze. METHODS: We performed two prospective studies of polyester (Mersilene) sutures in human penetrating keratoplasty done by one surgeon. Study I was a randomized comparison of combined running and interrupted Mersilene and nylon sutures in 45 consecutive eyes. Study II was a case series of single running Mersilene suture with postoperative adjustment of suture tension to manage astigmatism in 23 consecutive eyes. We evaluated the performance of the suture and the control of astigmatism. RESULTS: The interrupted running suture study demonstrated that interrupted Mersilene sutures were 5.5 times more likely to have handling-related complications than nylon interrupted sutures (p = .01); in addition, they were three times as likely to have tissue-related complications as nylon (p = .16). The running suture study demonstrated an unacceptable complication rate of 69% when Mersilene was used as a single adjustable running suture. At 6 months postoperatively, the median refractive astigmatism for the adjustable cases was 3.37 diopters (mean, 4.03 +/- 2.37 D). Eyes with significant suture-related complications were 2.85 times more likely to have greater than 4.00 D of refractive astigmatism than were eyes without suture-related complications. CONCLUSIONS: Mersilene is an undesirable suture for use in penetrating keratoplasty.

Adult↗