Internist, Ophthalmologists
35 years of experience

Accepting new patients
Alaska Native Medical Center, Phs
4315 Diplomacy Dr
University Area, Anchorage, AK 99508
907-729-2460
Locations and availability (1)

Education ?

Medical School Score Rankings
University of Arizona (1975)
  • Currently 3 of 4 apples
Top 50%

Awards & Distinctions ?

Awards  
One of America's Leading Experts on:
Radial Keratotomy (Refractive Surgical Procedure for Myopia)
Top Ten Doctors (2012)
Internal Medicine, Tudor Municipal Campus, Anchorage, AK
Associations
American Academy of Ophthalmology
Member

Affiliations ?

Dr. Mader is affiliated with 1 hospitals.

Hospital Affilations

Score

Rankings

  • Alaska Native Medical Center, Phs
    4315 Diplomacy Dr, Anchorage, AK 99508
    • Currently 1 of 4 crosses
  • Publications & Research

    Dr. Mader has contributed to 47 publications.
    Title Giant Cell Arteritis in Alaska Natives.
    Date March 2009
    Journal Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie
    Excerpt

    To investigate the incidence of biopsy-proven giant cell arteritis in the Native population of Alaska.

    Title Corneal Perforation and Delayed Anterior Chamber Collapse from a Devil's Club Thorn.
    Date September 2008
    Journal Cornea
    Excerpt

    PURPOSE: To report the corneal perforation and delayed collapse of the anterior chamber caused by the thorn from a devil's club plant. METHODS: An 8-year-old Alaska Native girl was struck in the eye with the stalk and leaves of a devil's club plant. Although 3 thorns from the plant were found to be lodged superficially in the corneal stroma, 1 was deeply embedded to the level of Descemet's membrane. The thorn was surrounded by a stromal infiltrate. Four days after the injury, the patient suffered a sudden collapse of the anterior chamber after the deeply embedded thorn became dislodged. RESULTS: The corneal wound was sutured, and the patient had an uneventful postoperative course. CONCLUSIONS: Our experience suggests that devil's club corneal injuries should be examined daily after the initial injury. The anterior chamber may suddenly collapse after a deeply embedded thorn becomes dislodged.

    Title Severe Eye Injuries in the War in Iraq, 2003-2005.
    Date February 2008
    Journal Ophthalmology
    Excerpt

    PURPOSE: To document the incidence and treatment of patients with severe ocular and ocular adnexal injuries during Operation Iraqi Freedom. DESIGN: Retrospective hospital-based observational analysis of injuries. PARTICIPANTS: All coalition forces, enemy prisoners of war, and civilians with severe ocular and ocular adnexal injuries. METHODS: The authors retrospectively examined severe ocular and ocular adnexal injuries that were treated by United States Army ophthalmologists during the war in Iraq from March 2003 through December 2005. MAIN OUTCOME MEASURES: Incidence, causes, and treatment of severe ocular and ocular adnexal injuries. RESULTS: During the time data were gathered, 797 severe eye injuries were treated. The most common cause of the eye injuries was explosions with fragmentation injury. Among those injured, there were 438 open globe injuries, of which 49 were bilateral. A total of 116 eyes were removed (enucleation, evisceration, or exenteration), of which 6 patients required bilateral enucleation. Injuries to other body systems were common. CONCLUSIONS: Severe eye injuries represent a significant form of trauma encountered in Operation Iraqi Freedom. These injuries were most commonly caused by explosion trauma.

    Title Long-term Graft Survival in Patients with Down Syndrome After Penetrating Keratoplasty.
    Date January 2007
    Journal Cornea
    Excerpt

    PURPOSE: To determine graft survival and long-term visual outcome after penetrating keratoplasty (PK) for keratoconus in patients with Down syndrome. METHODS: The records of all patients with Down syndrome who received PK by the same provider were reviewed. A retrospective analysis was performed to determine long-term graft survival, incidence of graft failure, and complication rate. RESULTS: Twenty-one PKs were performed on 18 eyes of 13 patients with Down syndrome with keratoconus. Three repeat PKs were performed for secondary graft failure. All 18 eyes had clear grafts at the most recent examination. Follow-up ranged from 4 to 88 months, with a mean of 34.9 months. The average age of patients was 42 years, with a range of 20 to 63 years. Preoperative visual acuity ranged from 20/160 to count fingers. Postoperatively, visual acuity was objectively measurable in 12 eyes of 8 patients and ranged from 20/30 to 20/200, with a mean of 20/60. Broken sutures and difficulties with unsedated suture removal complicated postoperative care in some patients. CONCLUSION: Clear grafts and improvements in visual acuity can be obtained after PK in patients with Down syndrome, but consideration must be given to careful postoperative care by health care providers and home support personnel.

    Title Ocular War Injuries of the Iraqi Insurgency,january-september 2004.
    Date January 2006
    Journal Ophthalmology
    Excerpt

    PURPOSE: To document the types and causes of ocular and ocular adnexal injuries treated by United States Army ophthalmologists serving in Iraq during the Iraqi Insurgency. DESIGN: Prospective hospital-based observational analysis of injuries. PARTICIPANTS: All coalition troops, enemy prisoners of war, and civilians with severe ocular and ocular adnexal injuries. METHODS: We prospectively examined severe ocular and ocular adnexal injuries that were treated at the 31st Combat Support Hospital during the portion of the Iraqi Insurgency that took place from January 20 through September 12, 2004. MAIN OUTCOME MEASURES: Incidences and characteristics of ocular and ocular adnexal injuries. RESULTS: During the time observed, 207 patients suffered severe ocular or ocular adnexal injuries, including 132 open globes. Blast fragmentation from munitions caused 82% of all injuries. The most common single cause of injury was the improvised explosive device (IED), which caused 51% of all injuries. Of 41 eye excisions, 24 were caused by IEDs. CONCLUSIONS: During the portion of the Iraqi Insurgency covered in our report, munitions fragments were the most common cause of ocular and ocular adnexal injuries. The single most common cause of injury was the IED, which produced devastating ocular and ocular adnexal injuries. The authors' findings indicate that polycarbonate ballistic eyewear could have prevented many, but not all, of the ocular injuries we report.

    Title Going to High Altitude with Preexisting Ocular Conditions.
    Date February 2004
    Journal High Altitude Medicine & Biology
    Excerpt

    The goal of this paper is to review how preexisting ocular conditions may be affected by altitude exposure. Such preexisting conditions include dry eye problems, monocular visual loss, and potential problems following refractive surgery procedures, as well as the possible changes associated with some forms of retinal and optic nerve diseases. Although most such altitude-related visual difficulties are relatively minor, some have resulted in serious morbidity or even death at high altitude. This review will give the reader background regarding these potentially debilitating conditions in order to better prepare for exposure to high altitude environments.

    Title Ocular Problems in Military Free Fall Parachutists.
    Date December 2002
    Journal Military Medicine
    Excerpt

    Military free fall parachutists may be unaware of the risk of corneal freezing and desiccation keratitis should their goggles come off during free fall in subfreezing temperatures. We determine the incidence of ocular difficulties in military free fall parachutists and the role freezing temperatures may play in causing these problems. We found that 79% of those who responded to the survey had lost their goggles at least once during free fall and 69% experienced ocular symptoms after goggle loss. Analysis shows a 30-fold increase in the duration of symptoms in subfreezing vs. above-freezing temperatures, with the odds of the ground mission being affected at 7.3 per 100 jumps in the subfreezing group. The rate of goggles coming off per jump is 3.3 times less with >75 jumps. Contact lenses are not protective and photorefractive keratectomy was not detrimental.

    Title The Ascent of Mount Everest Following Radial Keratotomy.
    Date May 2002
    Journal Wilderness & Environmental Medicine
    Title Analysis of Anterior and Posterior Corneal Curvature Changes Using Orbscan Technology in Radial Keratotomy Eyes Exposed to Hypoxia.
    Date March 2002
    Journal Journal of Cataract and Refractive Surgery
    Excerpt

    PURPOSE: To study the changes in anterior and posterior corneal curvatures in radial keratotomy (RK) and normal eyes exposed to hypoxia using Orbscan (Bausch & Lomb) technology. SETTING: Department of Ophthalmology, Madigan Army Medical Center, Tacoma, Washington, USA. METHODS: At sea level, 11 RK subjects and 10 control subjects were exposed to ocular surface hypoxia in 1 eye by filtering humidified, compressed 100% nitrogen (0% oxygen) through an airtight goggle system for 2 hours. The contralateral eye was exposed to humidified, compressed air (21% oxygen) simultaneously through the airtight goggle system. Orbscan analysis was performed in each subject before and immediately after gas exposure. This analysis included measurement of the anterior axial and posterior axial corneal curvatures as well as corneal pachymetry. RESULTS: In the RK eyes exposed to 100% nitrogen gas, there was a statistically significant flattening in the anterior axial corneal curvature (P = .0012) and in the posterior axial corneal curvature (P = .0067). Radial keratotomy and control eyes exposed to air and control eyes exposed to 100% nitrogen gas demonstrated no statistically significant change in the anterior axial or posterior axial corneal curvature. CONCLUSIONS: Corneal hypoxia induced a statistically significant flattening in the anterior axial and posterior axial corneal curvatures in eyes that had had RK. There was no significant change in these curvatures in RK eyes exposed to air and in control eyes exposed to air or 100% nitrogen gas.

    Title Refractive Changes Caused by Hypoxia After Laser in Situ Keratomileusis Surgery.
    Date March 2001
    Journal Ophthalmology
    Excerpt

    OBJECTIVE: To determine whether hypoxia induces refractive changes in subjects who have had laser in situ keratomileusis (LASIK) refractive surgery. DESIGN: Prospective paired eye clinical trial. PARTICIPANTS: There were 20 LASIK subjects (40 eyes) and 20 myopic non-LASIK controls (40 eyes). INTERVENTION: Each subject had one eye exposed to ocular surface hypoxia (humidified nitrogen) by use of an airtight goggle system at sea level for 2 hours. The other eye was simultaneously exposed to humidified, compressed air (21% oxygen) with the same airtight goggle system. MAIN OUTCOME MEASURES: Keratometry, cycloplegic refraction, and pachymetry were compared before and after exposure by use of repeated measures analysis of variance. RESULTS: A significant myopic shift (P: < 0.01) occurred in LASIK corneas exposed to hypoxia compared with myopic control subjects. A significant increase in corneal thickening occurred symmetrically in both LASIK and control subjects exposed to hypoxia. There was a trend toward corneal steepening (keratometry) in LASIK subjects, but this was not statistically significant. CONCLUSIONS: These results suggest that ocular surface hypoxia induces a myopic shift in LASIK subjects.

    Title Refractive Changes at High Altitude After Lasik.
    Date December 2000
    Journal Ophthalmology
    Title Stability of Vision During Space Flight in an Astronaut with Bilateral Intraocular Lenses.
    Date March 1999
    Journal American Journal of Ophthalmology
    Excerpt

    PURPOSE: To report excellent and stable vision in an astronaut during space flight after bilateral cataract surgery with intraocular lenses. METHODS: A 60-year-old physician mission specialist astronaut developed cataracts and underwent phacoemulsification with insertion of one-piece polymethylmethacrylate intraocular lenses that had 6-mm optics bilaterally. Several months later, he flew on a space shuttle mission. Ocular examinations were performed before and after the mission, and the patient was questioned about visual changes during flight. RESULTS: Ocular examinations demonstrated stable bilateral posterior chamber intraocular lenses. Our subject reported excellent vision during liftoff, 18 days of microgravity, changes in cabin pressure, and reentry. CONCLUSION: Results suggest that intraocular lenses are safe, effective, and well tolerated during space flight.

    Title Anterior Capsule Contraction with Foldable Silicone Intraocular Lenses.
    Date November 1998
    Journal Journal of Cataract and Refractive Surgery
    Excerpt

    PURPOSE: To examine the causes signs, and symptoms of anterior capsule contraction syndrome and the response to neodymium YAG (Nd:YAG) anterior capsulotomy. SETTING: Madigan Army Medical Center, Tacoma, Washington, USA. METHODS: This retrospective review comprised 70 cases of phacoemulsification with foldable plate-haptic silicone intraocular lens (IOL) implantation. Patients who developed anterior capsule contraction postoperatively, defined as the anterior capsule being visible through an undilated pupil, had a radial anterior capsulotomy with an Nd:YAG laser. Variables analyzed were visual acuity, subjective complaints, associated inflammation, and IOL decentration. RESULTS: Ten eyes of 9 patients (14%) developed anterior capsule contraction and had Nd:YAG laser radial anterior capsulotomy. Three of 9 patients reported decreased visual acuity and glare. Two other patients had chronic anterior chamber inflammation unresponsive to steroids after surgery that resolved after Nd:YAG anterior capsulotomy. Intraocular lens decentration was observed in 3 patients before the Nd:YAG capsulotomy. Posterior lens dislocation occurred in 1 patient after capsulotomy and required surgical lens exchange. CONCLUSION: One-piece foldable silicone IOLs may not provide enough peripheral capsule expansion.

    Title Infectious Crystalline Keratopathy Caused by Candida Guilliermondii.
    Date June 1998
    Journal American Journal of Ophthalmology
    Excerpt

    PURPOSE: To describe the manifestations of infectious crystalline keratopathy caused by Candida guilliermondii in a corneal transplant performed for pseudophakic bullous keratopathy. METHOD: Case report. RESULTS: Candida guilliermondii was identified as the causative organism of an indolent infectious crystalline keratopathy. Incisional lamellar biopsy provided diagnostic culture and histopathologic results. Histopathology showed aggregates of yeast elements between corneal stromal lamellae, without inflammation. The infection progressed despite a 6-week course of topical amphotericin B and an additional 6-week course of topical and oral fluconazole. Repeat penetrating keratoplasty resulted in clear graft, with no recurrent infection. CONCLUSIONS: Fungal keratopathy should be included in the differential diagnosis of infectious crystalline keratopathy. Numerous Candida species have been isolated in addition to the most common causative bacterial organism, Streptococcus viridans. Candida guilliermondii is yet one more causative agent of infectious crystalline keratopathy. Candida guilliermondii, a rare human pathogen, was resistant to medical therapy in this case.

    Title The Etiology of Refractive Changes at High Altitude After Radial Keratotomy. Hypoxia Versus Hypobaria.
    Date February 1998
    Journal Ophthalmology
    Excerpt

    OBJECTIVE: Refractive changes at high altitude that occur after radial keratotomy (RK) may be caused by hypoxia or hypobaria. DESIGN: A prospective study was performed to evaluate the effects of hypoxia on RK and non-RK corneas. PARTICIPANTS: There were 20 RK and 20 control eyes. INTERVENTION: These eyes were subjected to ocular surface hypoxia using an air-tight goggle system at sea level for 2 hours. MAIN OUTCOME MEASURES: Keratometry, cycloplegic refraction, and pachymetry were evaluated using repeated measures analysis of variance. RESULTS: A significant hyperopic shift (P < 0.0001) and corneal flattening (P < 0.0013) occurred in all subjects with RK compared with those of control subjects. Corneal thickening occurred symmetrically in both groups. CONCLUSIONS: These results suggest that refractive changes in subjects with RK occur at high altitude as a direct result of corneal hypoxia.

    Title Technique for the Removal of Limbal Dermoids.
    Date February 1998
    Journal Cornea
    Excerpt

    PURPOSE: To report a surgical technique for the removal of limbal dermoids. METHODS: We propose a method of deep excision and lamellar keratoplasty for limbal dermoid removal. RESULTS: This technique achieves near-normal postoperative appearance and function in patients with limbal dermoids. CONCLUSION: This method appears to offer an effective means of limbal dermoid removal.

    Title Bilateral Photorefractive Keratectomy with Intentional Unilateral Undercorrection Performed on an Aircraft Pilot.
    Date June 1997
    Journal Journal of Cataract and Refractive Surgery
    Title Refractive Changes During 72-hour Exposure to High Altitude After Refractive Surgery.
    Date September 1996
    Journal Ophthalmology
    Excerpt

    PURPOSE: The authors prospectively analyzed refractive and pachymetric parameters during exposure to high altitude after radial keratotomy (RK) and photorefractive keratectomy (PRK). METHODS: The authors measured manifest and cycloplegic refraction, keratometry, computed video keratography, and central and peripheral pachymetry in six subjects who have undergone RK (11 eyes), six who have undergone PRK (12 eyes), and nine with myopia (17 eyes) at sea level and on three consecutive days at 14,100 feet. All measurements were repeated 1 week after subjects returned to sea level. RESULTS: Subjects who have undergone RK demonstrated a significant and progressive increase in spherical equivalence (+0.30 +/- 0.50 diopters on day 1 and +1.52 +/- 1.01 diopters on day 3; P < 0.001) and a decrease in keratometry values during exposure to altitude when compared with control subjects with myopia. Healthy subjects and those who have had PRK demonstrated no significant change in refractive error. Pachymetry measurements demonstrated significant peripheral corneal thickening in all three groups (RK, P < 0.004; PRK, P < 0.007; control subjects, P = 0.0006) by day 3 at high altitude. Refraction, keratometry, and pachymetry returned to baseline (P = 1.000) after return to sea level. CONCLUSIONS: Seventy-two-hour exposure to high altitude in subjects who have had RK induces a significant, progressive, and reversible hyperopic shift in refraction with corresponding video keratographic and keratometric changes. The authors hypothesize that the high-altitude hypoxic environment causes increased corneal hydration in the area of the RK incisions, which may lead to central corneal flattening and a hyperopic shift in refractive error. Subjects who have had PRK and those with myopia are not susceptible to this refractive shift. The authors' RK data suggest that the time since surgery and the amount of surgery are related to the degree of hyperopic shift during altitude exposure.

    Title Corneal Abrasions: Diagnosis and Management.
    Date July 1996
    Journal American Family Physician
    Excerpt

    Corneal abrasions are characterized by sudden onset of eye pain, photophobia and tearing. The patient usually relates a history of recent eye trauma but may not recall an inciting event. The differential diagnosis includes direct mechanical injury, recurrent erosion syndrome, ultraviolet keratitis and infection. Most abrasions heal within 24 to 48 hours. Therapeutic modalities include cycloplegia and topical antibiotics. Other treatment methods include pressure patching, topical nonsteroidal anti-inflammatory drugs, bandage contact lenses, collagen shields, anterior stromal puncture and epithelial debridement.

    Title Effects of Simulated High Altitude on Patients Who Have Had Radial Keratotomy.
    Date May 1996
    Journal Ophthalmology
    Excerpt

    BACKGROUND: Previous studies documented diurnal myopic shifts in patients who have had radial keratotomy (RK). Recently, hyperopic shifts in these patients exposed to high altitude have been reported. A direct mechanical effect of reduced barometric pressure on surgically altered corneas has been theorized to cause this hyperopic shift. Another hypothesis implicates the effect of hypobaric hypoxia on the RK incisions. The authors examined the effect of a 6-hour exposure to decreased barometric pressure on 14 normal and 18 RK corneas. METHODS: Cycloplegic refraction, keratometry, corneal pachymetry, and tonometry were performed on seven control subjects and nine patients who have had RK. Measurements were obtained over 8 hours at sea level on day 1 of the study. Measurements were repeated on day 2 which included a 6-hour exposure to 12,000 feet simulated altitude in a hypobaric chamber. Results were compared between subjects and control subjects to determine the effect of a 6-hour exposure to decreased barometric pressure. RESULTS: There was no statistically significant difference in refraction or keratometry readings between control subjects and subjects who have had RK. Central corneal thickness decreased in the afternoon in RK eyes compared with control eyes. There was no clinically significant difference in intraocular pressure between subjects who have had RK and control subjects. CONCLUSIONS: A measurable hyperopic shift in RK corneas exposed to high altitude requires more than 6 hours to develop. A direct effect on corneal shape due to barometric pressure alone should produce a sudden change in refractive error. This study supports the hypothesis that a slow metabolic process is responsible for the previously documented hyperopic shifts induced by altitude. However, a barometric pressure effect requiring more than 6 hours to occur cannot be ruled out with the methodology used in this study.

    Title Refractive Changes at Extreme Altitude After Radial Keratotomy.
    Date July 1995
    Journal American Journal of Ophthalmology
    Excerpt

    PURPOSE: We studied the effects of altitude on four corneas that had undergone radial keratotomy and four normal corneas exposed to increasing elevation during a high-altitude excursion. METHODS: We measured visual acuity, cycloplegic refraction, keratometry, and intraocular pressure at sea level and after 24-hour exposure to 12,000 and 17,000 ft. RESULTS: We observed a significant increase in spherical equivalence (hyperopic shift) in radial keratotomy eyes exposed to altitude as compared to controls (P < .0001). The average change in spherical equivalent cycloplegic refraction from sea level to 12,000 ft was 1.03 +/- 0.16 diopters and from sea level to 17,000 ft was 1.94 +/- 0.26 diopters. We also observed a significant decrease in keratometry values at altitude as compared with control corneas (P < .0001). The average change in keratometry from sea level to 12,000 ft was 0.59 +/- 0.19 diopter and from sea level to 17,000 ft was 1.75 +/- 0.27 diopters. CONCLUSIONS: Although the specific origin of these changes is open to question, we hypothesize that hypoxic corneal expansion in the area of the radial keratotomy incisions may lead to central corneal flattening and a hyperopic shift in refractive error. The cornea that has undergone radial keratotomy appears to adjust constantly to changing environmental oxygen concentration, producing a new refractive error over a period of 24 hours or more. Additional study is required to identify with certainty the specific origin of the hyperopic shift at high altitude.

    Title Valsalva Retinopathy Associated with Transrectal Prostate Biopsy.
    Date December 1994
    Journal British Journal of Urology
    Title Calcific Band Keratopathy Associated with the Use of Topical Steroid-phosphate Preparations.
    Date June 1994
    Journal Archives of Ophthalmology
    Excerpt

    OBJECTIVE: To report a possible adverse effect of topical steroid-phosphate preparations and to identify factors that may contribute to the development of this effect. DESIGN: The medical records of five patients who developed calcium deposition in the cornea were reviewed and analyzed for possible contributing factors. PATIENTS: Five cases of calcium deposition in the cornea associated with the use of topical steroid-phosphate preparations are described. Scrapings from the cornea and/or specimens obtained at keratoplasty were available in all cases. These cases had the following characteristics in common: use of steroid-phosphate preparations (n = 5); multiple topical drops (n = 5); penetrating keratoplasty (n = 3); presence of epithelial defects (n = 4); history of herpetic stromal keratitis (n = 3) [corrected]; and history of iritis (n = 3). A hypothesis explaining calcium deposition in association with steroid-phosphate preparations is presented. CONCLUSIONS: We recommend withdrawal of steroid-phosphate preparations in patients who develop band keratopathy.

    Title Spitting Cobra Ophthalmia in United Nations Forces in Somalia.
    Date June 1994
    Journal American Journal of Ophthalmology
    Title Wound Adhesives for Eyelid Retraction.
    Date February 1994
    Journal American Journal of Ophthalmology
    Title Ocular and Ocular Adnexal Injuries Treated by United States Military Ophthalmologists During Operations Desert Shield and Desert Storm.
    Date November 1993
    Journal Ophthalmology
    Excerpt

    BACKGROUND: Ocular and ocular adnexal injuries, both combat-related and accidental, are common during wartime. In a combat setting, the eye is particularly vulnerable to serious injury from tiny flying particles that might minimally affect other parts of the body. The purpose of this study is to examine the incidence of serious ocular and ocular adnexal injuries that occurred during Operations Desert Shield and Desert Storm. METHODS: The authors retrospectively reviewed serious ocular and ocular adnexal injuries treated by United States Army and Navy ophthalmologists that occurred during Operations Desert Shield and Desert Storm. Only those injuries that resulted in, or would have resulted in, hospital admission because of the ocular or ocular adnexal injury alone are presented. RESULTS: During Desert Shield, 20 patients (23 eyes) suffered serious ocular or ocular adnexal injuries compared with 160 patients (198 eyes) in Desert Storm. During Desert Storm, 78% of all serious injuries were caused by blast fragmentation from munitions. More than one third of the 98 globe lacerations reported in this article were 10 mm or less in size. Of 35 enucleations performed during Desert Storm, 94% were the result of munitions fragments. CONCLUSIONS: During Operation Desert Storm, fragmentation wounds from munitions were the most common cause of ocular and ocular adnexal morbidity. The authors' findings indicate that polycarbonate ballistic protective eyewear could have prevented many of the ocular injuries that they report.

    Title Refractive Changes with Increasing Altitude After Radial Keratotomy.
    Date July 1993
    Journal American Journal of Ophthalmology
    Title Cerebral Blood Velocity and Other Cardiovascular Responses to 2 Days of Head-down Tilt.
    Date April 1993
    Journal Journal of Applied Physiology (bethesda, Md. : 1985)
    Excerpt

    Spaceflight induces a cephalad redistribution of fluid volume and blood flow within the human body, and space motion sickness, which is a problem during the first few days of spaceflight, could be related to these changes in fluid status and in blood flow of the cerebrum and vestibular system. To evaluate possible changes in cerebral blood flow during simulated weightlessness, we measured blood velocity in the middle cerebral artery (MCA) along with retinal vascular diameters, intraocular pressure, impedance cardiography, and sphygmomanometry on nine men (26.2 +/- 6.6 yr) morning and evening for 2 days during continuous 10 degrees head-down tilt (HDT). When subjects went from seated to head-down bed rest, their heart rate and retinal diameters decreased, and intraocular pressures increased. After 48 h of HDT, blood flow velocity in the MCA was decreased and thoracic impedance was increased, indicating less fluid in the thorax. Percent changes in blood flow velocities in the MCA after 48 h of HDT were inversely correlated with percent changes in retinal vascular diameters. Blood flow velocities in the MCA were inversely correlated (intersubject) with arterial pressures and retinal vascular diameters. Heart rate, stroke volume, cardiac output, systolic arterial pressure, and at times pulse pressure and blood flow velocities in the MCA were greater in the evening. Total peripheral resistance was higher in the morning. Although cerebral blood velocity is reduced after subjects are head down for 2 days, the inverse relationship with retinal vessel diameters, which have control analogous to that of cerebral vessels, indicates cerebral blood flow is not reduced.

    Title Intraocular Pressure and Retinal Vascular Changes During Transient Exposure to Microgravity.
    Date March 1993
    Journal American Journal of Ophthalmology
    Excerpt

    We measured intraocular pressures and retinal vascular diameters from 11 subjects during 20 seconds of microgravity produced by parabolic flight on board a KC-135 aircraft. Intraocular pressures increased 58% during parabolic flight compared to baseline values (19 +/- 1 mm Hg vs 12 +/- 1 mm Hg, respectively; P < .001). A 4% reduction in the caliber of retinal arteries was also noted during microgravity, but this change did not achieve statistical significance (7.8 +/- 0.3 pixels at zerogravity vs 8.1 +/- 0.3 pixels at 1g; P = .07). The increase in intraocular pressure and trend of arteries to constrict are thought to result from cephalad shifts in intravascular and extravascular body fluids as a result of the absence of the 1g hydrostatic gradient. The results of our study confirm that this fluid shift and its effects on the eye occur rapidly, within 20 seconds of exposure to microgravity.

    Title Changes in Keratometric Astigmatism After Suture Removal More Than One Year After Penetrating Keratoplasty.
    Date March 1993
    Journal Ophthalmology
    Excerpt

    BACKGROUND/PURPOSE: Selective removal of interrupted sutures and adjustment of a running suture can minimize astigmatism after penetrating keratoplasty, but the long-term effects of early suture manipulations remain largely unknown. The authors tested the hypothesis that the cornea becomes "fixed" more than 1 year after keratoplasty so that desirable refractive results will remain when all sutures are eventually removed. METHODS: The authors reviewed retrospectively the changes in astigmatism that occurred when all remaining sutures were removed from 162 eyes 1 to 6 years after penetrating keratoplasty. Single-running sutures were used in 130 eyes, double-running sutures in 20 eyes, and a combination of interrupted and running sutures in 12 eyes. RESULTS: Removal of single-running sutures caused an average decrease in astigmatism of 0.52 diopters (D) from 6.10 +/- 4.41 D to 5.57 +/- 3.14 D. However, the astigmatism in 62% of eyes changed 2 or more D (range, 11.94 to -17.87 D), and the range changed more than 20 degrees in 55% of eyes. The average vectorial change was 6.5 +/- 4.3 D (range, 0.59 to 19.8 D). There was no decrease in the amount of astigmatic change with increasing time between surgery and suture removal. Graft size and diagnosis had no effect on the amount of astigmatic change. Astigmatic errors became stable, with less than 1 D of change between successive examinations within 6 months after suture removal. Similar results were obtained for eyes with double-running and interrupted-running sutures. CONCLUSIONS: Corneal astigmatism may change unpredictably and by large amounts when all remaining sutures are removed 1 to 6 years after penetrating keratoplasty.

    Title Viral Keratitis.
    Date January 1993
    Journal Infectious Disease Clinics of North America
    Excerpt

    Viruses that affect the cornea produce changes that range from benign, self-limited conjunctivitis to sight-threatening scarring and vascularization of the cornea. In this article, the forms of viral keratitis most commonly encountered by the clinician are reviewed. The epidemiology, clinical presentation, and treatment of infection by Herpes simplex virus, varicella zoster virus, and the adenoviruses are discussed. Also included are other viral infections of the cornea.

    Title Corneal Transplantation in a Patient with Congenital Sensory Neuropathy.
    Date June 1992
    Journal Cornea
    Excerpt

    We describe penetrating keratoplasty for corneal scarring in a patient with congenital sensory neuropathy and repeated self-mutilation. This patient underwent a successful penetrating keratoplasty but suffered a series of postoperative complications necessitating three repeat grafts. Some of these complications were attributable to decreased corneal sensation while others were caused by self-mutilation. Since his last penetrating keratoplasty 4 years ago, this patient has had functional visual acuity.

    Title Intraocular Pressure in Microgravity.
    Date February 1992
    Journal Journal of Clinical Pharmacology
    Title Gentamicin Resistance in Staphylococcal Corneal Ulcers.
    Date November 1991
    Journal Cornea
    Excerpt

    Gentamicin sulfate is frequently included in the initial treatment of suspected bacterial keratitis. We present the gentamicin susceptibility test results for coagulase-negative staphylococci and Staphylococcus aureus isolated from corneal ulcers in nine patients. All were resistant to gentamicin by standard disk diffusion techniques. The minimum inhibitory concentrations were very high, some exceeding the concentration normally achieved by frequent topical application of antibiotics. Clinicians should be aware that strains of staphylococci extremely resistant to gentamicin may cause keratitis. An antibiotic with broad activity against Gram-positive organisms, such as a cephalosporin or vancomycin, should be included as part of the initial therapy for corneal ulcers that might be caused by staphylococci.

    Title Keratoconjunctivitis Sicca Caused by Diphenoxylate Hydrochloride with Atropine Sulfate (lomotil)
    Date April 1991
    Journal American Journal of Ophthalmology
    Title Intraocular Pressure, Retinal Vascular, and Visual Acuity Changes During 48 Hours of 10 Degrees Head-down Tilt.
    Date December 1990
    Journal Aviation, Space, and Environmental Medicine
    Excerpt

    Intraocular pressures, retinal vascular diameters, and visual acuities of nine men (ages 19-29), were repeatedly measured while the subjects were tilted 10 degrees head-down for 48 h and while they were seated before (baseline), and after the tilt. An immediate increase in intraocular pressure, measured by pneumatonometer (4.7 +/- 0.6 mm Hg, p less than 0.001) was recorded when subjects assumed the head-down position, and diurnal variations in intraocular pressures were observed for the 48 h. The initial and final head-down intraocular pressures were not significantly different (18.9 +/- 1.2 mm Hg vs. 17.9 +/- 1.4 mm Hg, respectively). However, when subjects resumed the sitting position, intraocular pressures fell below the initial sitting values (14.2 +/- 0.9 pre vs. 11.2 +/- 0.5 post, p less than 0.04). Computer image analysis of the retinal vasculature detected a 6% and 2% reduction in the caliber of arteries and veins, respectively, as compared with sitting baseline values. No changes in visual acuity were documented during the 48 h of head-down tilt. Our data suggest that the choroidal blood reservoir increases in volume over 48 h at continuous head-down position with a compensatory decrease in aqueous volume. These findings may explain intraocular pressure changes noted in astronauts during previous space missions and in studies associated with change in body position.

    Title Penetrating Keratoplasty in Ectodermal Dysplasia.
    Date October 1990
    Journal American Journal of Ophthalmology
    Title Spontaneous Bleeding from a Normal-appearing Iris: an Unusual Cause of Atypical Amaurosis Fugax.
    Date October 1990
    Journal Annals of Emergency Medicine
    Excerpt

    Amaurosis fugax, or fleeting loss of vision, is often attributed to embolic retinovascular disease. In this setting, there is appropriate concern for associated cerebrovascular complications. Extensive and expensive vascular evaluation may be indicated. Less often, local ocular abnormalities may mimic embolic visual loss. We describe a case of sudden, transient, monocular visual loss in a 67-year-old woman caused by Valsalva-induced intraocular bleeding from a seemingly normal iris.

    Title An Automated Method of Quantifying Retinal Vascular Responses During Exposure to Novel Environmental Conditions.
    Date September 1990
    Journal Ophthalmology
    Excerpt

    The width of retinal arteries and veins was measured by digital image analysis using an automated vessel-tracking software program. Mean coefficients of variations in vessel width of less than 3% were easily achieved from digitized 35-mm retinal photographs taken with a table-top or hand-held fundus camera. Retinal images were analyzed from seven subjects exposed to sea level or altitudes equivalent to 10,000 (3048 m), 17,500 (5334 m), and 25,000 (7620 m) ft and nine subjects exposed to sea level and 14,110 ft (4300 m). At each altitude, retinal veins dilated more than did arteries (5 +/- 1 versus 0 +/- 1% at 10,000 ft and 28 +/- 9% versus 9 +/- 2% at 25,000 ft; veins versus arteries, respectively). However, widths of retinal arteries and veins were reduced in nine subjects tested after 15 minutes, 24 hours, and 48 hours of 10 degrees head-down tilt; and values varied inversely with intraocular pressures (IOP). Hand-held retinal fundus photography and digital image analysis were found to provide a sensitive and objective method for detecting and quantifying retinal vascular responses in humans exposed to novel environments.

    Title A New Method of Obtaining Cells from the Cornea and Conjunctiva for Cytologic Study.
    Date June 1990
    Journal Archives of Ophthalmology
    Title Bilateral Paralimbal Scleromalacia Perforans.
    Date March 1990
    Journal American Journal of Ophthalmology
    Title Effect of Eye Color on Heart Rate Response to Intramuscular Administration of Atropine.
    Date February 1989
    Journal Journal of the Autonomic Nervous System
    Excerpt

    Melanin has been previously shown to modify the mydriatic response to atropine instillation. Skin and iris pigmentation has also been shown to modify aspects of the heart rate response to injected atropine, although these observations have been generally overlooked. In this study, 20 healthy non-smoker male subjects, ages 20-30 years, were injected by two different automatic injector devices and the mydriatic and heart rate responses in the first 90 min were reported. The group included 8 brown-eyed, 4 hazel-eyed, and 8 blue-eyed subjects. Although there were differences in the rate of atropine delivery between the two injection devices, the heart rate responses were independently modified by eye color to a magnitude of difference as great as the differences between injectors. Subjects with more pigmented irides (brown-eyed) showed a more rapid rise in heart rate compared to less pigmented irides (hazel-eyed and blue-eyed subjects). Following injection by the device with a slower atropine absorption rate, these differences were particularly enhanced and an abbreviated bradycardic phase of the heart rate response was observed for the brown-eyed subjects. This observation confirms earlier reports and suggests the possibility of an interference by melanin (in the iris or elsewhere) in atropine accessibility to selected muscarinic target sites.

    Title The Treatment of an Enlarged Sarcoid Iris Nodule with Injectable Corticosteroids.
    Date October 1988
    Journal American Journal of Ophthalmology
    Title Enlarged Pupillary Membranes.
    Date May 1988
    Journal Journal of Pediatric Ophthalmology and Strabismus
    Excerpt

    Pupillary membranes are very commonly found on routine microscopic examination of the anterior segment and are usually of no clinical significance. We describe a 4-year-old child with grossly enlarged pupillary membranes that formed a mesh-like arc over the entire pupillary aperture in both eyes. Although these membranous strands were very prominent, the child had normal visual acuity.

    Title Intraocular Lenses in Aviators: a Review of the U.s. Army Experience.
    Date August 1987
    Journal Aviation, Space, and Environmental Medicine
    Excerpt

    Intraocular lenses are known to be efficacious in the correction of aphakia, but their suitability and durability in Army aviators has not been previously evaluated. Eight experienced pilots (preoperative flight time average: 7,660 hours), who had intraocular lens implants following removal of cataractus lenses, were studied. All had returned to flight duty, seven as pilots, with a total of 2,700 hours postoperative flight time accumulated. All were very pleased with the surgery and with the effectiveness of their lenses. Minor problems included: halos around lights in low illumination (5/8 pilots), erythropsia (2/8), and difficulties with a fixed focal length (2/8). Two aviators reported significant visual problems: complications associated with a platinum loop iris supported intraocular lens, and discomfort and glare stemming from traumatic corneal scarring. A detailed ophthalmological examination revealed abnormalities (5/8 pilots), but none which would be directly attributed to flying. Modern intraocular lenses appear to be an acceptable means of correcting aphakia in Army aviators.

    Title Conjunctival Oxygen Tension at High Altitude.
    Date February 1987
    Journal Aviation, Space, and Environmental Medicine
    Excerpt

    Transconjunctival oxygen tension (PcjO2) was studied using a hypobaric chamber and during mountaineering excursions. Measurements obtained during acute chamber exposures (15-20 min) at sea level, 1829 m (6,000 ft), 3048 m (10,000 ft), 4267 m (14,000 ft) and return to sea level were (means +/- SEM): 60.1 +/- 2.7, 49.1 +/- 1.8, 38.3 +/- 2.4, 27.4 +/- 1.5, and 61.1 +/- 2.8 mm Hg, respectively (n = 13). The ratio of PcjO2 to arterial blood oxygen tension (PaO2) did not change in a consistent manner between sea level and 4267 m; PcjO2 was 74 +/- 6.9% of PaO2. The 16 subjects participating in the mountaineering phase of the study revealed similar means at sea level and 1829 m (57.4 +/- 2.4 and 46.3 +/- 1.9 mm Hg respectively), but a smaller decrement was observed at 3048 m (43.0 +/- 1.6 mm Hg). The difference between mountain and chamber values may be accounted for by a partial acclimatization to altitude brought about by longer exposure on the mountain excursions. A comparison between PcjO2 and transcutaneous oxygen tension during the chamber study suggests that a greater precision and sensitivity is obtained with measurement of oxygen tension at the conjunctival site. PcjO2 measurement is a non-invasive reflection of PaO2 which is suitable for continuous monitoring during hypoxia studies.

    Title A Method of Removing Displaced Silicone Tubing from the Nasolacrimal Duct System.
    Date July 1985
    Journal American Journal of Ophthalmology

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