W. Sponsel

University of Texas at San Antonio, Biomedical Engineering, Faculty Member

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William Sponsel and his colleagues were the first to confirm clinically that glaucomatous neurodegeneration is coordinated by the brain. They later showed that dynamic function in glaucomatous eyes is also modulated by the CNS. Sponsel is a long time member of the Executive Committee of the International Society for Glaucoma Surgery, has authored over 100 peer reviewed publications, and runs an active glaucoma subspecialty clinic in San Antonio Texas. He is Professor of Vision Sciences at UIW and adjunct Professor of Biomedical Engineering at UTSA.

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Manipal Academy of Higher Education

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Johns Hopkins University

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Bogazici University

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Papers by W. Sponsel

Association of retinal capillary perfusion with visual status during chronic glaucoma therapy

Ophthalmology, 1997

The purpose of the study is to determine whether retinal microcirculation is associated with the ... more The purpose of the study is to determine whether retinal microcirculation is associated with the degree of visual function in glaucomatous eyes receiving chronic bilateral medical therapy with topical beta-blockers. A nonrandomized, 3-year prospective clinical study was undertaken on 37 patients with glaucoma and normal visual acuity receiving symmetric topical medication in both eyes. Humphrey 30-2, Henson CFA 2000, and Vistech 3 and 6 cycles/degree contrast sensitivity were obtained bilaterally at multiple visits, along with Oculix 1000 blue-field estimates of perimacular leukocyte velocity. The mean asymmetry of measurements obtained throughout the treatment period for each pair of eyes was determined, and correlations were obtained to assess visual function asymmetry circulatory asymmetry. Significant associations were observed between blue-field entoptic capillary leukocyte velocity measurements and those for all three visual function testing methods, the eye with the superior ...

Transaxillary sympathectomy--is a one-stage bilateral procedure safe?

The British journal of surgery, 1982

Quantitative supra-threshold static perimetry; the value of field score and asymmetry analysis in the early detection of chronic open angle glaucoma

Documenta Ophthalmologica Proceedings Series, 1987

Modification of the Heidelberg retinal flowmeter to record pattern and flicker induced blood flow changes

Documenta ophthalmologica. Advances in ophthalmology, 2003

We tested a prototype stimulator interfaced with a commercially available scanning laser ophthalm... more We tested a prototype stimulator interfaced with a commercially available scanning laser ophthalmoscope designed to measure retinal capillary perfusion (Heidelberg Retina Flowmeter (HRF)). The add-on stimulator optically superimposed the image of a monitor display on to the subject's retina coaxially with the imaging optics of the HRF. The purpose of the study was to determine if flicker and pattern stimulation presented in this manner could evoke changes in retinal perfusion that could be measured by the HRF. The prototype stimulator projected 55 degrees visual angle circular fields of homogeneous flicker, alternating checkerboard, and multi-focal m-sequence hexagonal patterns on the retina of 10 human subjects during acquisition of images by the HRF. Images were successfully acquired and processed. HRF perfusion values during flicker and pattern stimulation were not significantly different from control values. Results of the present study and a previously published study showi...

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Sildenafil increases ocular perfusion

by W. Sponsel and Gianmarco Paris

Laser Scanning: Update 1, 2001

Purpose: Our goal was to determine whether visual system responses to sildenafil accompany shifts... more 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), fullthreshold 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.

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Importance of Visual Field Score and Asymmetry in the Detection of Glaucoma

Optometry and Vision Science, 1986

... HENSON D. (1) ; HOBLEY A. ; BALWANTRAY CHAUHAN ; SPONSEL W. ; DALLAS N. ; Affiliation(s) du o... more

Uniocular Drug Trial

by Relief Jones and W. Sponsel

Ophthalmology, 2005

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Frequency doubling perimetry

American journal of ophthalmology, 1998

UK PubMed Central (UKPMC) is an archive of life sciences journal literature.

Prevalence of Glaucoma

Ophthalmology, 1992

Purpose: The purpose of this study is to determine the prevalence of glaucoma in the population p... more

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Prevent Blindness America Visual Field Screening Study: AUTHOR REPLY

American Journal of Ophthalmology, 1996

... Champ visuel pathologie. ; Santé publique. ; Mots-clés espagnols / Spanish Keywords. Déficien... more ... Champ visuel pathologie. ; Santé publique. ; Mots-clés espagnols / Spanish Keywords. Déficiencia. ; Campo visual. ; Descubrimiento. ; Eficacia. ; Campimetría. ; ... Sensibilidad. ; Especificidad. ; Hombre. ; Ojo patología. ; Campo visual patología. ; Salud pública. ; Localisation / Location ...

Retinal Hemodynamics Using Scanning Laser Ophthalmoscopy and Hemorheology in Chronic Open-angle Glaucoma

Ophthalmology, 1993

Purpose: Recent studies suggest that elevated intraocular pressure is not the only causative fact... more Purpose: Recent studies suggest that elevated intraocular pressure is not the only causative factor for the development of visual field loss and optic nerve damage in glaucomatous eyes. The authors determine whether retinal hemodynamics or blood fluidity are alternated in eyes of patients with open-angle graucoma compared with those of age-and sex-matched healthy subjects.

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Periocular Accumulation of Timolol and Betaxolol in Glaucoma Patients Under Long-term Therapy

Survey of Ophthalmology, 1999

Purpose: To determine if betaxolol or timolol is present in measurable concentration in the Tenon... more Purpose: To determine if betaxolol or timolol is present in measurable concentration in the Tenon capsule in patients under long-term topical therapy. Methods: Small (1-cc) specimens of Tenon capsule were removed at the time of filtering surgery from 15 glaucoma patients under long-term preoperative topical therapy, nine of whom had been treated with timolol and six of whom had been receiving betaxolol. Methanol extracts of these tissue samples were analyzed quantitatively for the presence of either ␤ -adrenergic antagonist by high-performance liquid chromatography. Results: Drug was detected in every specimen. A mean total of 2.6 (range, 0.1-30.0) g of betaxolol was detected per 1-cc specimen. Conclusion: Timolol and betaxolol penetrate the conjunctiva and accumulate in the Tenon capsule. In patients under long-term therapy, the periocular tissue can accumulate a greater quantity of beta-antagonist than is present in a daily dosage of applied eyedrops, manyfold higher than the maximal intraocular concentration. ( Surv Ophthalmol 43 [Suppl 1] :S210-S213, 1999.

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Sildenafil and Ocular Perfusion

by W. Sponsel and Gianmarco Paris

New England Journal of Medicine, 2000

To the Editor: Jones et al. (Jan. 13 issue)1 describe a Ten-nessee high school whose students and... more

Physiological perturbation of ocular and cerebral blood flow as measured by scanning laser ophthalmoscopy and color doppler imaging

Survey of Ophthalmology, 1994

Retinal blood flow regulation in health remains poorly described. We hypothesized that retinal pe... more Retinal blood flow regulation in health remains poorly described. We hypothesized that retinal perfusion is controlled to provide constant O2 delivery to that tissue, and that changes in retinal blood flow in response to chemical stimuli parallel changes in carotid and retrobulbar perfusion. Accordingly, in 11 young adults with normal eye examinations, we measured retinal blood flow indices (via scanning laser ophthalmoscopy [SLO] during fluorescein angiography) and carotid, ophthalmic, and central retinal arterial blood flow indices (via Doppler imaging [CDI]) under control, hypoxic (alveolar PO2 = 55 +/- 3 mmHg) and hyperoxic (alveolar PO2 = 655 +/- 18 mmHg) conditions. The three conditions were counterbalanced in order and isocapnia was maintained in each. Retinal arterial mean dye velocity and arteriovenous passage time, as measured by SLO, were slowed by hyperoxia and accelerated by hypoxia, in rough proportion to the changes in arterial O2 content (+/- 10%; p &lt; 0.05). In the seven subjects in which relative measurements of retinal arterial diameters were obtained, neither hypoxia nor hyperoxia significantly altered vessel diameter. At the same time, mean retinal capillary transit velocity was independent of PO2, suggesting that, in health, retinal capillaries may be recruited as PO2 falls. O2-induced changes in carotid, ophthalmic, or central retinal arterial blood flow velocities (via CDI) were not found, though a wide coefficient of variation (30% for CDI vs. 14% for SLO) may have contributed to this failure. We conclude that, under isocapnic conditions, retinal perfusion may be regulated to provide constant O2 delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of Superficial Optic Nerve Head Capillary Blood Velocities by Scanning Laser Fluorescein Angiography

Journal of Glaucoma, 1994

Scanning laser ophthalmoscopy is capable of producing video fluorescein angiograms with high spat... more Scanning laser ophthalmoscopy is capable of producing video fluorescein angiograms with high spatial and temporal resolution. Digital image analysis of these angiograms has been used to produce measures of capillary flow velocities in perimacular capillaries. We have recently utilized the same technique to measure flow velocities in the superficial capillary layers of the optic nerve head. We performed video fluorescein angiograms using the Ro-denstock (Germany) scanning laser ophthalmoscope. The passage of hyperflu-orescent particles through optic nerve head capillaries was imaged in five healthy subjects (two men and three women). The flow velocity for each of eight to 10 capillaries in each subject was measured three to five times. The mean capillary blood flow velocity for all subjects was 2.71 mm/s. These results are similar to those obtained in perifoveal capillaries. We have demonstrated that scanning laser fluorescein angiography can be adapted for measuring superficial optic disk capillary flow velocities. The possibility remains for the imaging of capillaries in deeper portions of the optic nerve head by using the confocol abilities of the scanning laser ophthalmoscope. Future use of this technique may aid our understanding of the pathophysiology of optic neuropathy.

Retinal Capillary Hemodynamics and VEP/Pressure Tolerance: Evidence of Retinal Microcirculatory Compromise in Treated Glaucomatous Eyes

by W. Sponsel and Sandy Zetlan

Ophthalmologica, 1997

Measurements of retinal leukocyte velocity were made in single eyes of 6 glaucomatous adults and ... more Measurements of retinal leukocyte velocity were made in single eyes of 6 glaucomatous adults and 9 normal subjects at each of 4 discrete levels of IOP elevation assigned according to the characteristics of prior pattern-evoked cortical potential pressure tolerance measurements. Glaucomatous eyes failed to demonstrate any stabilization in retinal leukocyte velocity at pressures above 45 mm Hg, with velocities 33% lower than normal for a comparable degree of IOP elevation (p &amp;amp;lt; 0.012). Even at baseline IOP, leukocyte velocity was 27.2% slower in the treated glaucomatous eyes than in normal control eyes (p &amp;amp;lt; or = 0.013), despite comparable baseline IOP levels in both groups.

Anatomical Manifestations of Primary Blast Ocular Trauma Observed in a Postmortem Porcine Model

by W. Sponsel and R. Glickman

Investigative Ophthalmology & Visual Science, 2014

We qualitatively describe the anatomic features of primary blast ocular injury observed using a p... more We qualitatively describe the anatomic features of primary blast ocular injury observed using a postmortem porcine eye model. Porcine eyes were exposed to various levels of blast energy to determine the optimal conditions for future testing. We studied 53 enucleated porcine eyes: 13 controls and 40 exposed to a range of primary blast energy levels. Eyes were preassessed with B-scan and ultrasound biomicroscopy (UBM) ultrasonography, photographed, mounted in gelatin within acrylic orbits, and monitored with high-speed videography during blast-tube impulse exposure. Postimpact photography, ultrasonography, and histopathology were performed, and ocular damage was assessed. Evidence for primary blast injury was obtained. While some of the same damage was observed in the control eyes, the incidence and severity of this damage in exposed eyes increased with impulse and peak pressure, suggesting that primary blast exacerbated these injuries. Common findings included angle recession, internal scleral delamination, cyclodialysis, peripheral chorioretinal detachments, and radial peripapillary retinal detachments. No full-thickness openings of the eyewall were observed in any of the eyes tested. Scleral damage demonstrated the strongest associative tendency for increasing likelihood of injury with increased overpressure. These data provide evidence that primary blast alone (in the absence of particle impact) can produce clinically relevant ocular damage in a postmortem model. The blast parameters derived from this study are being used currently in an in vivo model. We also propose a new Cumulative Injury Score indicating the clinical relevance of observed injuries.

912 Exercise Hastens Retinal Arteriovenous Passage Time

Medicine & Science in Sports & Exercise, 1994

Paintball Trauma and Mechanisms of Optic Nerve Injury: Rotational Avulsion and Rebound Evulsion

Investigative Ophthalmology & Visual Science, 2011

Ballistic impact studies and supercomputer modeling were performed to elicit the mechanisms of op... more Ballistic impact studies and supercomputer modeling were performed to elicit the mechanisms of optic nerve rupture that may accompany blunt ocular trauma. Paintball ocular impact responses were studied with abattoir-fresh porcine eyes. Physics-based numerical code CTH was used to produce robust geometric and constitutive models of the eye and orbit, providing a comparative 3-D finite volume model to help determine the mechanisms underlying empirical ballistic observations. Among 59 porcine eye specimens submitted to paintball impact in the 1- to 13-J range, 10 (17%) disengaged completely from the orbital mount. In each instance the paintball penetrated the orbit adjacent to the globe, producing rotation and eventual globe repulsion, dramatically evident on high-speed film images. Supercomputer modeling yielded similar globe-expulsive results when orbital constraints were in place, but not when these were removed. In these models, tangential (grazing) impact sheared the nerve flush with the globe via a strain rate effect within 260 μs, with minimal posterior displacement and just 5° of globe rotation. Midperipheral impact produced compressive globe distortion and posterior displacement, followed by rebound and tractional nerve avulsion 10 mm behind the lamina after 700 μs and 20° of globe rotation. Constitutive modeling studies suggest at least two trajectory-dependent mechanisms for optic nerve rupture with paintball impact on the eye. Tangential glancing blows produce strain-rate rotational avulsion, abscising the optic nerve with minimal internal globe disruption, whereas off-center direct impact produces slower rotational-rebound evulsion, traumatizing the globe and breaching the nerve posteriorly. The latter mechanism would be expected to arise more commonly and would most likely be clinically masked by accompanying intraocular injury.