Flow velocity and pulsatility of the ocular circulation in chronic intracranial hypertension.

OBJECTIVES: The aim of this study is to examine the relationship of ocular blood flow velocities and pulsatility to intracranial pressure (ICP). METHODS: We measured arterial and venous flow velocities using color Doppler imaging (CDI) and calculated resistance indices for the central retinal (CRA) and the ophthalmic (OA) arteries from 16 patients (32 eyes) with chronic intracranial hypertension (ICH) and varying degrees of ICP and papilledema. The results were compared with normal data from 16 age-matched, healthy subjects. RESULTS: Arterial flow velocities were significantly decreased for the aggregate subject group compared with controls. A corresponding rise in arterial resistance with increasing ICP in the mild-moderate range was noted. Unexpectedly, with more severe elevations of ICP these trends reversed. CONCLUSIONS: In mild-moderate increased cerebrospinal fluid (CSF) pressure, a reduction of flow velocities may result because of increased vascular resistance. Paradoxically, in more severe chronic ICH, we hypothesize that local autoregulatory vascular changes and/or diversion of cerebral blood flow into the ophthalmic circulation may normalize these parameters. This phenomenon may partially underlie the relative sparing of visual function early in the course of pseudotumor cerebri (PTC), regardless of actual ICP levels.

[Strabismus surgery under subconjunctival anesthesia: technique and evaluation by patient and his surgeon]. / Augenmuskeloperationen in subkonjunktivaler Anästhesie: Technik sowie Wahrnehmung durch den Patienten und seinen Operateur.

BACKGROUND: In adults, eye muscle surgery can be performed under local anesthesia without retrobulbar injection. We wanted to know how patients and surgeons perceive this procedure. PATIENTS AND METHODS: 50 patients and 3 surgeons were interviewed with a questionnaire after operation on one or two straight eye muscles, including revisions in 11 cases. The patients were sedated with benzodiazepines. The conjunctiva was anesthetized with tetracaine eye drops. During the operation, mepivacaine was irrigated under the muscle insertion using a blunt needle. RESULTS: The patients perceived little or no pain during the operation. This corresponded to the surgeon's judgement. 96% of the patients would prefer local over general anesthesia in case of a second operation. CONCLUSION: The technique can be recommended for surgery of rectus muscles in adults, even in the case of revision.

Correlation of relative afferent pupillary defect and estimated retinal ganglion cell loss.

BACKGROUND: The relative afferent papillary defect (RAPD) is an important parameter for quantifying the loss of neuronal function in asymmetric optic nerve disease. We wanted to assess its correlation with retinal ganglion cell loss, estimated from visual field defects, using a recently described method. METHODS: In 36 patients with unilateral optic nerve disease, the RAPD was measured using an automated, computerized infrared pupillometer. The percentage of ganglion cell loss was estimated with clear templates. RESULTS: We found a highly significant correlation between the RAPD and estimated ganglion cell loss. The correlation was higher for Humphrey visual fields than for Goldmann visual fields measured with the 14e and 12e stimulus. CONCLUSION: The RAPD correlates well with estimated retinal ganglion cell loss in optic nerve disease. Humphrey visual fields seem to reflect the ganglion cell loss better than Goldmann visual fields. The spatial distribution of pupillomotor retinal ganglion cells seems to be proportional to the distribution of light-sensitive ganglion cells projecting to the lateral geniculate nucleus.

[Enophthalmos caused by orbital metastasis of breast carcinoma]. / Enophthalmus durch Orbitametastase eines Mamma-Carcinoms.

BACKGROUND: Orbital metastatic disease usually leads to exophthalmos but rarely to enophthalmos. We report a case of a metastasis causing enophthalmos. PATIENT: A 68-year-old woman had mastectomy for breast cancer six years prior to presentation. She complained of double vision when looking sideways. The right eye showed a motility reduction in all directions and a slight ptosis. She had 4 mm enophthalmos, and the eyelids were sunk into the orbit. There were no signs of optic nerve damage. Magnetic resonance imaging showed a retrobulbar mass surrounding the optic nerve and infiltrating the muscles. The space of the orbital fat was reduced. A biopsy confirmed the diagnosis of metastatic breast carcinoma. Histologically, the connective tissue was infiltrated by lymphocytes, and the nuclei of the tumor cells where aligned in a linear "indian file" pattern. 30% of the tumor cells contained the estrogen-receptor protein, 40% the progesterone-receptor protein. The CA-15/3 and CEA levels were elevated. The patient underwent orbital radiation with 50 Gy. During the following 2 months, the enophthalmos increased to 6 mm. DISCUSSION: We suggest the following hypothesis as the cause of enophthalmos in orbital metastases: The tumor growth goes along with fibrosis. Subsequent shrinkage of the connective tissue pulls the eye back into the orbit. The ensuing elevation of tissue pressure leads to atrophy of the retrobulbar fat. The increase of tumor volume is too slow to compensate for the fat atrophy. Slowly progressive enophthalmos with reduced motility is nearly pathognomonic of metastatic scirrhous breast carcinoma. In rare cases, a diffusely infiltrating carcinoma of the gastrointestinal tract may cause a similar picture.

The role of YAG-laser iridotomy in pigment dispersion syndrome.

We determined iris configuration and posterior-chamber depth before and after YAG-laser iridotomy in 20 eyes with pigment dispersion syndrome using high-resolution ultrasound and measured the intraocular pressure after a mean of 9.1 months. The iris configuration and posterior-chamber depth of our patients were compared with those of an age- and refraction-matched control group of 20 eyes without pigment dispersion. In the patient group, 8 eyes had a concave iris configuration with shallow posterior chambers and 12 eyes had planar irides. In the former group the posterior-chamber depth increased significantly after treatment. In the latter group it did not change. In the normal control group, three subjects also had concave irides. There was a significant correlation between posterior-chamber depth and refraction in patients with pigment dispersion syndrome, but not in the normal control group. After the follow-up period the intraocular pressure of treated eyes was not significantly lower than that of untreated eyes. Iris concavity can also occur in normal individuals and may therefore be only a pathogenetic cofactor in the pigment dispersion syndrome. Laser iridotomy proved to flatten irides but did not significantly decrease the intraocular pressure.

[Filling of optico-ciliary shunt vessels in papilledema: an indicator of pressure in the optic nerve sheath]. / Füllung optikoziliarer Shuntgefässe bei Stauungspapille: ein Indikator für den Druck in der Sehnervenscheide.

BACKGROUND: Optico-ciliary shunt vessels can occur in papilledema. It appears possible that the diameter of these vessels correlates with the pressure in the optic nerve sheath. CASE REPORT: A 31-year-old woman with pseudotumor cerebri had atrophic papilledema with optico-ciliary shunt vessels at the disc margin. After optic nerve sheath fenestration these vessels collapsed and ultrasonography revealed a decrease in the nerve sheath diameter. Sixteen days later, the optico-ciliary shunt vessels were filled again. Nine hours after lumbar puncture, the optico-ciliary shunt vessels disappeared for 13 hours, but the nerve sheath diameter did not decrease. After acetazolamide, 1g q d, neither the diameter of the optico-ciliary shunt vessels nor that of the nerve sheath decreased. CONCLUSION: The diameter of optico-ciliary shunt vessels may be an indicator of the pressure within the optic nerve sheath.

[Indications for eye examination of HIV patients--screening parameters for cytomegalovirus retinitis]. / Indikation zur Augenuntersuchung von HIV-Patienten--Screening-Parameter für CMV-Retinitis.

BACKGROUND: To reduce the burden of frequent visits at the physician we have checked (I) for which ocular manifestations in HIV-infection screening of asymptomatic patients is worthwhile and (II) which parameters may indicate patients at risk for CMV-retinitis. PATIENTS AND METHODS: The clinical data of 215 HIV-infected patients were analyzed retrospectively. Only those ocular manifestations were considered suitable for screening that (a) endanger vision, (b) are treatable, (c) can be diagnosed sufficiently early and (d) are common. Furthermore (1) CDC-stage, (2) CD4+ count, (3) HIV-retinopathy, (4) CMV-uria and (5) CMV-antibodies were checked for their usefulness in indicating patients at risk for CMV-retinitis. RESULTS: Ophthalmological screening of asymptomatic HIV-patients should focus on cytomegalovirus (CMV)-retinitis because early diagnosis of this common blinding disease improves the visual outcome. 85 of 215 HIV-infected patients had a CD4+ count less than 50 cells/microliters 25% of these patients developed CMV-retinitis (21/85). The risk for CMV-retinitis rose to 38% (13/34) when the low CD4+ count was accompanied by CMV-uria. The proportion of patients with CMV-retinitis did not increase when HIV-retinopathy had been diagnosed earlier (12/48 = 25%). CMV-serology and CDC-classification were not helpful in screening for CMV-retinitis. CONCLUSIONS: We recommend the following ophthalmological screening scheme for HIV-patients without ocular symptoms: (1) patients with a CD4+ count < 100 cells/microliters should be checked every third month and (2) those with a CD4+ count < 50 cells/microliters and CMV-uria every sixth week.

Mesencephalic clefts with associated eye movement disorders.

OBJECTIVE: To describe two patients with mesencephalic midline clefts and associated eye movement disorders. DESIGN: Case reports. RESULTS: The first patient developed bilateral internuclear ophthalmoplegia with exotropia, reduced convergence, right ptosis, right fourth-nerve palsy, and right elevator palsy several years after meningitis with hydrocephalus. The second patient had bilateral internuclear ophthalmoplegia with exotropia, reduced convergence, bilateral ptosis, limited upward gaze, and right hypertropia since childhood. In both patients, magnetic resonance imaging showed a midline cleft extending from the cerebral aqueduct into the midbrain. CONCLUSION: It is likely that the clefts affected the oculomotor nuclei and medial longitudinal fasciculi, accounting for the eye movement disorders.

Effect of surgical technique on the increase in intraocular pressure after cataract extraction.

BACKGROUND AND OBJECTIVE: A prospective study was performed to determine the influence of surgical technique on the increase in intraocular pressure (IOP) after cataract surgery. PATIENTS AND METHODS: Three groups of 30 patients each underwent either extracapsular cataract extraction with sclerocorneal suture (ECCE), phacoemulsification with sclerocorneal suture (PS), or phacoemulsification with a sutureless scleral tunnel (PT). RESULTS: Each group experienced a significant increase in IOP 5 to 7 hours after surgery: 20.2 +/- 7.9 mm Hg for ECCE, 11.2 +/- 8.3 mm Hg for PS, and 4.7 +/- 8.7 mm Hg for PT. The differences in the increases among the three groups were significant. CONCLUSION: PT [corrected] produces the lowest postoperative increase in IOP and should be considered for patients with glaucomatous damage.

Intraocular pressure rise after phacoemulsification with posterior chamber lens implantation: effect of prophylactic medication, wound closure, and surgeon's experience.

AIMS: A prospective clinical trial was carried out to evaluate the effect of prophylactic medication, the technique of wound closure, and the surgeon's experience on the intraocular pressure rise after cataract extraction. METHODS: In 100 eyes, the intraocular pressure was measured before as well as 2-4, 5-7, and 22-24 hours after phacoemulsification and posterior chamber lens implantation. Each of 25 patients received either 1% topical apraclonidine, 0.5% topical levobunolol, 500 mg oral acetazolamide, or placebo. Forty four eyes were operated with sclerocorneal sutureless tunnel and 56 eyes with corneoscleral incision and suture. Sixty three operations were performed by experienced surgeons (more than 300 intraocular operations) and 37 by inexperienced surgeons (less than 200 intraocular operations). RESULTS: The pressure increase from baseline to the maximum 5-7 hours after surgery did not differ significantly (p = 0.8499) for apraclonidine (9.5 mm Hg), levobunolol (7.2 mm Hg), acetazolamide (7.8 mm Hg), and placebo (8.6 mm Hg). The increase was significantly (p = 0.0095) lower in eyes with corneoscleral tunnel (5.5 mm Hg) than in eyes with corneoscleral suture (10.5 mm Hg) and significantly (p = 0.0156) lower for experienced (6.6 mm Hg) than for inexperienced surgeons (11.2 mm Hg). CONCLUSIONS: The intraocular pressure rise after phacoemulsification and posterior chamber lens implantation depends strongly on the technique of wound closure and the surgeon's experience. Compared with these two factors, the effect of prophylactic medication can be neglected.

Iridotomy in the treatment of pigmentary glaucoma: documentation with high resolution ultrasound.

In pigmentary glaucoma, reverse pupillary block is one mechanism presumed possible for backward bowing of the iris leading to iris-zonular rubbing. Therefore, increasing numbers of patients are being treated by laser iridotomy. We demonstrate five patients with pigmentary glaucoma whose iris configuration was examined by high-resolution ultrasound biomicroscopy before and after laser iridotomy. Of these patients, three had a severe case of posterior iris bowing with iris-zonular rubbing. In these cases, the ultrasound biomicroscope revealed an anterior motion of the iris diaphragm after iridotomy. The other two patients had no direct iris-zonular contact and displayed a normal iris curvature that did not change after iridotomy. YAG-laser iridotomy is a prophylactic treatment in pigmentary glaucoma for a subgroup of patients in whom an iris concavity with iris-zonular rubbing can be demonstrated by high-resolution ultrasound or equivalent methods.

[Increased intraocular pressure after cataract extraction--effect of surgical technique, surgical procedure and preventive drug administration. A prospective, randomized double-blind study]. / Intrakularer Druckanstieg nach Kataraktextraktion--Einfluss von Operationstechnik, Operationserfahrung und medikamentöser Prophylaxe. Eine prospektive, randomisierte Doppelblindstudie.

BACKGROUND: We performed a double-masked, randomized and prospective study to compare the effect of surgical technique, surgeon's experience, and prophylactic medication on the intraocular pressure rise after cataract extraction. PATIENTS AND METHODS: Intraocular pressure of 120 patients was measured the day before, as well as two to four, five to seven and 22 to 24 hours after uncomplicated cataract extraction. 47 patients were operated with phacoemulsification and sclerocorneal sutureless tunnel (phaco/tunnel). 61 patients with phacoemulsification and corneoscleral incision and suture (phaco/suture), and 12 patients with extracapsular technique (ECCE). 48 operations were done by inexperienced surgeons (less than 200 intraocular operations), 72 by experienced surgeons (300-2000 intraocular operations). Patients were treated with either levobunolol, acetazolamide, apraclonidine, or placebo. Each treatment group contained 30 patients. RESULTS: In all groups, the mean intraocular pressure increased to a maximum at five to seven hours after surgery. The pressure rise was significantly higher in the ECCE group (20.6 mm Hg) than in the phaco/suture group (10.5 mm Hg) and in the phaco/tunnel group (5.4 mm Hg, p always < 0.05). Eyes operated by inexperienced surgeons had a significantly (p < 0.005) greater pressure rise (12.9 mm Hg) than eyes operated by experienced surgeons (7.1 mm Hg). Treatment had no significant (p = 0.41) effect on the intraocular pressure rise. CONCLUSION: The intraocular pressure rise after cataract extraction strongly depends on the surgical technique and to a lesser extent, on the surgeon's experience. At least for phacoemulsification, the effect of the prophylactic medication used in this study is small and appears to be clinically irrelevant.

Asymmetries in preattentive line detection.

We tested the relative contribution of absolute orientation and collinearity to asymmetries in preattentive line detection. Subjects reported the location of a single line that was tilted by 16 deg against the orientation of the background lines. Perceptual pop-out strength was quantified as the threshold presentation time to correctly locate the salient element. We found that (1) threshold times were significantly shorter in vertical than in oblique background lines and that (2) threshold times were significantly shorter in collinear than in non-collinear background lines. Our data suggest that the sensitivity of preattentive processes for orientation gradients is modulated by both collinearity and absolute orientation.

Asymmetries in texture perception.

Single elements in textures segregate preattentively from the background if they differ in special features from surrounding elements (pop-out). Oblique targets on a background of vertical line elements are more easily detected than vertical targets on a ground of oblique elements. We wanted to find out whether this perceptional asymmetry depends on the absolute orientation or on the alignment of the background lines. Using the method of constant stimuli, we measured the thresholds of detection times in five subjects using four different arrangements of line patterns. The subjects indicated the position of a salient element in a forced-choice procedure. For all subjects, detection times were shortest if background lines were either vertical or collinear. Otherwise, detection times were significantly longer by a factor of 3. Figure-ground segregation is facilitated if background lines are either vertical or collinear.

[Peripheral retinal correspondence after retinal detachment]. / Periphere Netzhautkorrespondenz nach Amotio retinae.

BACKGROUND: Occasionally, patients who underwent surgery for complicated retinal detachment report spatial distortions. This may be due to a translocation of photoreceptors when they become reattached to the pigment epithelium. We wanted to find out if, and to what extent, similar translocations occur after a simple buckling operation. METHODS: Binocular retinal correspondence was used as an indicator of photoreceptor translocation. Correspondence was measured in the peripheral visual field at eccentricities of 5, 10 and 20 degrees, using a mirror haploscope. We examined two normal observers, one patient having had surgery for complicated retinal detachment including retinotomy, and 23 patients who had simple radial buckling operations. RESULTS: The patient who had received complicated detachment surgery including retinotomy revealed a tremendous shift in correspondence. Of the 23 patients who had simple radial buckle operations, only 10 were able to sustain central fixation while being tested in the periphery. Of these 10 patients, 2 showed distortions of peripheral retinal correspondence in the area of previous retinal detachment. However, only one of them remembered some spatial distortion after surgery. CONCLUSION: As a rule, photoreceptors become correctly reattached after radial buckle operations for retinal detachment. Rarely, vertical or horizontal translocations of about 1 to 2 degrees occur, but this does not usually lead to metamorphopsia.

Distortions in two-dimensional visual space perception in strabismic observers.

Amblyopic subjects were asked to memorize circles of different radii (2, 4 and 6 degrees), and then to reconstruct them monocularly with each eye, point by point (12 points per circle). The resulting two-dimensional maps of visual space showed considerable distortions, including expansion, shrinkage and torsion of specific regions of the visual field of the amblyopic eye, but not the normal eye. Based on the differences between the two eyes, we computed complex two-dimensional patterns (gratings, checkerboards, optotypes, written text, natural scenes) as "seen" monocularly with the amblyopic eye. These reconstructed patterns were then compared with drawings of the same patterns observed through the amblyopic eyes of the same subjects. The reconstructed patterns only partially reflected the actual perception for the amblyopic eyes. The compensation of complex, globally-extended scenes in comparison to the distortions obtained by local, punctate settings probably reflects cooperative interactions occurring at higher brain levels.

[Errors of monocular localization in strabismic amblyopia. Two-dimensional distortion]. / Fehler der monokularen Lokalisation bei Schielamblyopie. Zweidimensionale Verzerrungen.

Spatial distortions, i.e. spatial localization errors, and precision of localization were measured monocularly in the central visual field of 7 normal observers, 17 strabismic amblyopes and 2 anisometropic amblyopes. The task of the subjects was to construct circles of 2 degrees, 4 degrees and 6 degrees radius around a fixation point, using the dominant and the amblyopic eye in turn. Normal observers set distances on the vertical meridian smaller than distances on the horizontal meridian. Anisometropic amblyopes showed localization errors and variances similar to those of normal observers. The amblyopic eyes of strabismic observers with a large angle strabismus and deep amblyopia showed significant, individually different localization errors correlating with the depth of amblyopia. Strabismics with microstrabismus exhibited parallels between monocular localization and dichoptic retinal correspondence.

Two-dimensional spatial distortions in human strabismic amblyopia.

Two-dimensional space perception was measured in the central visual field of amblyopic subjects under special consideration of spatial distortions and spatial uncertainty. The subjects had to construct circles with different radii around a given fixation point. Subjects with deep strabismic amblyopia were showed to exhibit considerable distortion in the amblyopic eye. Each subject exhibited an individual distortion pattern. The dominant eye showed distortions similar to those seen in normal observers. Subjects with mild strabismic amblyopia, strabismic alternators and anisometropic amblyopes did not exhibit any significant spatial distortions. Data from dichoptic localization experiments indicate that anomalous retinal correspondence might contribute to monocular spatial distortions.