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Biomedical subjects

D K Sanford

Publications and source records attributed to D K Sanford.

4 recordsLinked to original sources
PubMed2001

Sildenafil increases ocular perfusion.

PURPOSE: Our goal was to determine whether visual system responses to sildenafil accompany shifts in ocular perfusion. The human choroid, which supports the metabolic function of the outer retina, is an erectile tissue, analogous in many respects to the corpus cavenosum. METHODS: Right eyes of 12 normal adults were evaluated before and 2 h after 50 mg oral dose of sildenafil. Pulsatile ocular blood flow (POBF), intraocular pressure (IOP), Heidelberg retinal flowmetry (HRT), 4.26 cpd, 7.5 Hz temporally-modulated contrast sensitivity (CS), full-threshold C-20 frequency doubling technology (FDT) perimetry, and blood pressure (BP) were measured. RESULTS: POBF (+29.4%; p > 0.016) and CS (+33.6%; p > 0.014%) increased within 110 (+/-7.7) minutes after sildenafil administration. No subject demonstrated decreases in either variable. HRF flow values increase among 7 of the 9 eyes producing stable scans (+8.2%; p > 0.1). FDT values did not change significantly, nor did systemic pulse amplitude or mean IOP. CONCLUSIONS: Since IOP and systemic pulse amplitude both remained stable after sildenafil administration, while POBF values increased to a level nearly one third greater than baseline. It appears sildenafil can induce intrinsic change in the choroidal vasculature, with an apparently positive impact on pericentral contrast sensitivity. This effect may be of clinical utility.

Administration, Oral↗
PubMed1998

Response of intraocular pressure to retrobulbar and peribulbar anesthesia.

BACKGROUND AND OBJECTIVE: To evaluate the response of intraocular pressure (IOP) to retrobulbar and peribulbar anesthesia. PATIENTS AND METHODS: Patients were prospectively masked and randomized to receive either 4 cc of retrobulbar anesthesia (X = 29) or 6 cc of peribulbar anesthesia (X = 30), each consisting of a 50:50 mixture of 2% xylocaine and 0.75% bupivacaine with 150 units of hyaluronidase. IOPs were measured pre-anesthesia and 1, 2, and 5 minutes post-anesthesia in nonglaucoma patients undergoing cataract extraction and intraocular lens implantation. RESULTS: Mean IOPs in the retrobulbar group as determined with a tonometer were 18.24, 18.66, 19.14, and 17.86 mm Hg pre-anesthesia and 1, 2, and 5 minutes post-anesthesia, respectively. In the peribulbar group, the mean IOPs were 18.53, 21.20, 20.40, and 19.20 mm Hg, respectively. The 1-minute pressures in the two groups were statistically different (P = .023). Within the peribulbar group, the 1- and 2-minute pressures were statistically different from the pre-anesthesia IOP (P = .001 and P = .018, respectively). CONCLUSION: Peribulbar anesthesia, with its higher volume of anesthetic (6 vs 4 cc), results in a higher initial IOP. This difference was slight and short lived, and occurred in the absence of any external ocular compression. This study may have application in avoiding elevation of IOP in select patients undergoing a local procedure.

Aged↗
PubMed1991

Simultaneous penetrating keratoplasty, extracapsular cataract extraction, and intraocular lens implantation.

The postoperative results of 210 consecutive eyes in 177 patients who had simultaneous penetrating keratoplasty, extracapsular cataract extraction, and posterior chamber intraocular lens (IOL) implantation (triple procedure) were reviewed. All procedures were performed by one surgeon between January 1980 and December 1989. The most common diagnosis requiring a triple procedure was Fuchs' endothelial dystrophy. The remainder of the patients required the procedure for either corneal scarring, keratoconus, or Chandler's syndrome. Of the 210 grafts, 191 (91%) remained clear with a mean follow-up of 53 months (range 6 to 116 months). The mean preoperative keratometry (K) reading (n = 161) was 44.51/44.85 (SD 4.86/4.94), and the mean postoperative K reading (n = 111) was 44.29/43.50 (SD 3.83/3.63). The mean IOL power (n = 196) was + 20.87 diopters (D) (SD 2.86). The mean postoperative best visual acuity (n = 166) was 20/65 with a range from 20/20 to less than 20/400, although 61% had 20/50 acuity or better and 92% had 20/100 acuity or better. The mean spherical correction in 155 eyes was - 1.38 (SD 2.89), and the mean positive refractive cylinder was + 3.21 (SD 2.20). One hundred forty six of the 155 eyes with reported refractions (96%) had 6 D or less of refractive cylinder. Correlation of the recipient-donor disparity % and refractive cylinder was significant such that as disparity increased refractive cylinder increased (r = 0.197, P = .021). Correlation of the recipient-donor disparity % and keratometric cylinder indicated a similar trend but was not significant (r = 0.105, P = .310).

Adult↗