1/9. Laser in situ keratomileusis-induced optic neuropathy.OBJECTIVE: To report a case of bilateral optic neuropathy after bilateral laser-assisted in situ keratomileusis (LASIK) surgery. DESIGN: Observational case report. methods: Complete eye examination with detailed evaluation of the optic nerve, detailed medical history, stereo disc photographs, GDx Nerve Fiber Analyzer testing, Humphrey 24-2 SITA visual field testing, diurnal intraocular pressure measurement, serologic evaluation, and magnetic resonance imaging of the brain and orbits. MAIN OUTCOME MEASURES: optic nerve status, visual field status, and visual acuity. RESULTS: A subject with previously healthy optic nerves had bilateral optic neuropathy develop after LASIK surgery. This neuropathy manifested with a subjective decrease in visual field, normal visual acuity, normal color vision, relative afferent pupillary defect, increased cupping of the optic nerve with focal neuroretinal rim defects, decreased nerve fiber layer thickness, and nerve fiber bundle-type visual field defects. The subject had no other risk factors for optic neuropathy. No other cause of neuropathy was identified. CONCLUSIONS: Optic neuropathy is a potential vision-threatening complication of LASIK surgery. This complication may be due to barotrauma or ischemia related to extreme elevation of intraocular pressure by the suction ring. Careful examination of the optic nerve before and after LASIK surgery is warranted.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
2/9. Anterior ischemic optic neuropathy after a trans-Atlantic airplane journey.PURPOSE: To report a case of anterior ischemic optic neuropathy after a trans-Atlantic airplane journey. DESIGN: An observational case report. methods: A 48-year-old healthy man presented with severe visual loss in his left eye within 12 hours after a 15-hour-long trans-Atlantic airplane flight. The patient underwent slit-lamp examination, funduscopy, fluorescein angiography, automated perimetry, and various blood examinations. RESULTS: visual acuity was LE: 20/30, and a mild left eye relative afferent pupillary defect was noted. Funduscopic evaluation revealed an edematous optic disk in the left eye with a para-diskal retinal hemorrhage. fluorescein angiography revealed a leaking optic disk, and perimetry showed an inferior hemi-field scotoma. Anterior ischemic optic neuropathy was diagnosed. CONCLUSION: Prolonged airplane travel may compromise vision either by a thromboembolic mechanism caused by prolonged immobilization or by a vasospasm mechanism induced by the low oxygen pressure during the flight.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
3/9. Quantitative pupillometry, a new technology: normative data and preliminary observations in patients with acute head injury. Technical note.The authors prospectively used a new hand-held point-and-shoot pupillometer to assess pupillary function quantitatively. Repetitive measurements were initially made in more than 300 healthy volunteers ranging in age from 1 to 87 years, providing a total of 2,432 paired (alternative right eye, left eye) measurements under varying light conditions. The authors studied 17 patients undergoing a variety of nonintracranial, nonophthalmological, endoscopic, or surgical procedures and 20 seniors in a cardiology clinic to learn more about the effects of a variety of drugs. Additionally, the authors carried out detailed studies in 26 adults with acute severe head injury in whom intracranial pressure (ICP) was continuously monitored. Finally, five patients suffering from subarachnoid hemorrhage were also studied. Quantitative pupillary measurements could be reliably replicated in the study participants. In healthy volunteers the resting pupillary aperture averaged 4.1 mm and the minimal aperture after stimulation was 2.7 mm, resulting in a 34% change in pupil size. constriction velocity averaged 1.48 /- 0.33 mm/second. Pupillary symmetry was striking in both healthy volunteers and patients without intracranial or uncorrected visual acuity disorders. In the 2,432 paired measurements in healthy volunteers, constriction velocity was noted to fall below 0.85 mm/second on only 33 occasions and below 0.6 mm/second on eight occasions (< one in 310 observations). In outpatients, the reduction in constriction velocity was observed when either oral or intravenous narcotic agents and diazepam analogs were administered. These effects were transient and always symmetrical. Among the 26 patients with head injuries, eight were found to have elevations of ICP above 20 mm Hg and pupillary dynamics in each of these patients remained normal. In 13 patients with a midline shift greater than 3 mm, elevations of ICP above 20 mm Hg, when present for 15 minutes, were frequently associated with a reduction in constriction velocity on the side of the mass effect to below 0.6 mm/second (51% of 156 paired observations). In five patients with diffuse brain swelling but no midline shift, a reduction in constriction velocities did not generally occur until the ICP exceeded 30 mm Hg. Changes in the percentage of reduction from the resting state following stimulation were always greater than 10%, even in patients receiving large doses of morphine and propofol in whom the ICP was lower than 20 mm Hg. Asymmetry of pupillary size greater than 0.5 mm was observed infrequently (< 1%) in healthy volunteers and was rarely seen in head-injured patients unless the ICP exceeded 20 mm Hg. Pupillometry is a reliable technology capable of providing repetitive data on quantitative pupillary function in states of health and disease.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
4/9. Retinal nerve fiber layer thickness in optic tract syndrome.BACKGROUND: Optic tract syndrome (OTS) is characterized by incongruous homonymous hemianopia and a perpendicular pattern of bilateral optic atrophy due to the optic tract lesion. However, loss of retinal nerve fiber layer thickness (RNFLT) associated with OTS has not been quantitatively assessed. CASE: A 20-year-old woman with blunt head trauma showed normal visual acuity, color vision, ocular motility, and intraocular pressure. Because of a relative afferent pupillary defect in her left eye and left-sided homonymous hemianopia, we suspected right-sided optic tract damage, although magnetic resonance imaging detected no intracranial lesion. OBSERVATIONS: Using optical coherence tomography (OCT), the RNFLT of this case was measured at 31 months after the trauma and compared with age-matched normal controls (n = 41). Nasal, temporal, superior, and inferior quadrant RNFLT was reduced by 22%, 21%, 5%, and 46% in the right eye and 76%, 64%, 25%, and 27% in the left eye, respectively. The reduction was > 3 x the standard deviation of the normal mean values in the nasal and temporal quadrants of the left eye and in the inferior quadrant of the right eye. CONCLUSIONS: OCT can determine the RNFLT reduction corresponding to the characteristic patterns of optic atrophy of OTS.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
5/9. Bilateral cataract and corectopia after laser eyebrow [corrected] epilation.PURPOSE: To report a patient with bilateral cataract and corectopia after laser epilation of the eyebrows. DESIGN: Single interventional case report. methods: A 27-year-old woman with a history of bilateral eyebrow laser epilation complained of oval pupils, reduced visual acuity, and photophobia immediately after laser epilation of both upper-eyelid regions. The following examinations were performed: visual acuity, slit-lamp examination, pupillary light reflex, perimetry, tonometry, gonioscopy, and funduscopy with contact lenses. The follow-up period was 9 months. MAIN OUTCOME MEASURES: visual acuity, intraocular pressure, inflammation, and pupillary distortion. RESULTS: Her best baseline visual acuities were 20/25 (right) and 20/40 (left). Examination showed bilateral corectopia with superior iris atrophy, iris stroma clump at the pupillary margin, and pigment residues in the inferior chamber. A cataract developed in the anterior subcapsular regions of the lenses. CONCLUSIONS: Laser epilation at the eyelid may result in irreversible cataract and iris atrophy.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
6/9. Anterior capsule adherence to iris leading to pseudophakic pupillary block.We present a rare case of anterior capsule adherence to the iris following extracapsular cataract extraction with posterior chamber intraocular lens implantation and leading to pseudophakic pupillary block. There were no synechiae at the pupillary margins associated with the capsule/iris adherence, but aqueous was entrapped behind the iris and intraocular pressure rose. Laser iridotomy was temporarily beneficial, but it had to be repeated several times.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
7/9. Pupillary block during cataract surgery.Sudden phakic pupillary block occurred immediately upon cortical cleaving hydrodissection during cataract surgery in two patients. We believe this unique complication is related to the recent introduction of viscoelastics with properties that enhance the maintenance of the anterior chamber during capsulorhexis. We postulate that the cause of the block was a combination of O-ring capsulocortical and iridocapsular seals that tamponade hydrodissection fluid posteriorly. Additional precipitating factors were diabetes, poorly dilating pupils, and increased vitreous pressure, which may have contributed to the sudden and irreversible nature of this block. If this complication is not recognized, an aqueous misdirection syndrome may ensue, requiring pars plana vitrectomy. Immediate mechanical breakage of the pupillary and capsular block, resulting in an immediate decrease in intraocular pressure from greater than 70 mm Hg, may cause severe retinal vascular damage. These cases stress the importance of mechanical pupil dilation to prevent this serious complication of cataract surgery.- - - - - - - - - - ranking = 1keywords = pressure (Clic here for more details about this article) |
8/9. Visual field loss following vitreous surgery.OBJECTIVE: To assess possible causes of visual field loss following vitreous surgery. DESIGN: charts of 8 patients prospectively identified, who developed visual field loss following vitreous surgery, were reviewed to characterize this newly recognized syndrome and assess possible causes. RESULTS: Two patients had preexisting chronic open-angle glaucoma and 1 had ocular hypertension. Indications for surgery included 4 eyes with macular holes, 1 eye with epiretinal membrane, 2 eyes with rhegmatogenous retinal detachment, and 1 eye with retinal detachment and giant retinal tear. All patients received retrobulbar anesthesia. Seven of 8 patients had fluid/gas exchange with installation of long-acting bubbles. In 1 patient with a macular hole, a small hemorrhage was noted along a vessel coming off the nerve superotemporally while attempting to engage the posterior cortical vitreous intraoperatively. This patient developed an inferior visual field defect. No intraocular pressure (IOP) measurements greater than 26 mm Hg were recorded in any eye perioperatively. Visual field defects included 4 eyes with inferotemporal defects, 2 eyes with inferior altitudinal defects, 1 eye with a cecocentral scotoma, and 1 eye with a superonasal defect. Only 1 patient had worsened visual acuity. A relative afferent pupillary defect was observed in 4 eyes and disc pallor in 5 eyes. CONCLUSIONS: Central or peripheral visual field loss can now be recognized as a possible complication of vitreous surgery. In some cases, a relative afferent pupillary defect and optic disc pallor are present, suggesting that the optic nerve is the site of injury. Possible mechanisms include ischemia due to elevated IOP or fluctuations in IOP, optic nerve damage from retrobulbar injection, direct intraoperative mechanical trauma to the optic nerve, indirect injury from vigorous suction near the optic nerve leading to shearing of peripapillary axons or vessels, or a combination of these. Certain optic nerves may be more susceptible to injury because of preexisting compromise from glaucoma or vascular disease.- - - - - - - - - - ranking = 0.5keywords = pressure (Clic here for more details about this article) |
9/9. Ultrasound biomicroscopic findings in humans with shallow anterior chamber and increased intraocular pressure after the prone provocation test.PURPOSE: To investigate ultrasound biomicroscopic findings in human eyes with shallow anterior chamber and risk of anterior chamber angle-closure glaucoma after the prone provocation test. methods: A total of 32 consecutive patients (64 eyes) with bilateral shallow anterior chamber who were at risk for primary angle-closure glaucoma underwent the prone provocation test in a lit room. Before and immediately after measurement of intraocular pressure in this test, high-frequency ultrasound biomicroscopy was performed in the horizontal and vertical directions, and the chamber angle views were recorded at the 3-, 6-, 9-, and 12-o'clock positions. RESULTS: Ten eyes of six patients exhibited an increase in intraocular pressure of 8 mm Hg or more, a positive response, with the remainder showing a negative response to the test. In the eyes with a positive response to the test, the profile of the iris showed a markedly convex shape with a large space behind the posterior iris. However, the anterior chamber angle of each eye remained open, even during the high level of intraocular pressure caused by the provocation. CONCLUSIONS: The present results suggest that no angle closure occurs during the initial increase of intraocular pressure after the prone provocation test. Such an initial increase of intraocular pressure was associated with high pressure in the posterior chamber because of the relative pupillary block. A time lag was observed between the high intraocular pressure caused by the pupillary block and the occurrence of angle closure.- - - - - - - - - - ranking = 5.5keywords = pressure (Clic here for more details about this article) |