Orbital apex syndrome

PURPOSE OF REVIEW

Visual loss from optic neuropathy and ophthalmoplegia involving multiple cranial nerves are the hallmarks of an orbital apex syndrome. Historically, the terms superior orbital fissure, orbital apex, and cavernous sinus have been used to define the anatomic locations of a disease process. However, the diagnostic evaluation and management is similar for each of these entities. The authors reviewed the literature on the diagnosis and evaluation of disorders involving the orbital apex.

RECENT FINDINGS

High-resolution MRI is the preferred modality for evaluating most lesions involving the orbital apex. CT is a useful tool in the setting of trauma, to evaluate bone involvement, or when MRI is contraindicated. Although laboratory studies may be useful adjuncts in the diagnostic evaluation of lesions involving the orbital apex, surgical biopsy is often required for definitive diagnosis.

SUMMARY

Orbital apex syndromes may result from a variety of inflammatory, infectious, neoplastic, iatrogenic/traumatic, and vascular conditions. A detailed history with review of systems is important in narrowing the differential diagnosis. Management is directed at the underlying cause and may be guided by surgical biopsy. Corticosteroids may be useful if an inflammatory etiology is suspected, but should be used with caution.

Relationship between Retinal Nerve Fiber Layer and Visual Field Sensitivity as Measured by Optical Coherence Tomography in Chiasmal Compression

PURPOSE

To investigate the spatial relationship between retinal nerve fiber layer (RNFL) thickness measured with optical coherence tomography (OCT) and visual field sensitivity (VFS) measured by standard automated perimetry (SAP) in chiasmal compression.

METHODS

Twenty-six patients with chiasmal compression were enrolled. RNFL thickness was measured with the StratusOCT and VFS with SAP (Humphrey Field Analyzer; both from Carl Zeiss Meditec, Dublin, CA). Relationships between RNFL thickness (in clock hours, hemifields, and sectors) and VFS (zones were divided into hemifields, quadrants, and sectors based on a validated visual field map) expressed in a decibel scale and 1/lambert (L) were evaluated by linear and nonlinear regression. Coefficients of determination (R(2)) were calculated by using a multivariate model.

RESULTS

Average RNFL thickness correlated strongly with pattern standard deviation (PSD; R = 0.622) and mean deviation (MD; R = 0.413). The four strongest correlations were between the 8 o'clock OCT position (temporal disc), with the temporal hemifield (R = -0.813), the superotemporal quadrant (R = -0.847), the inferotemporal quadrant (R = -0.855), and the field sector representing the papillomacular bundle (R = -0.809). Coefficients of determination improved significantly in all sectors when time since surgery was included in the regression model-most notably, average thickness and 1/L (R(2) = 0.35-0.49), the decibels (R(2) = 0.31-0.47), and the temporal sector (R(2) = 0.44-0.57).

CONCLUSIONS

This is the first study to compare the structure-function correlation of RNFL measured by OCT with SAP in patients with chiasmal compression. RNFL is topographically related globally and sectorally to decreased SAP, with the temporal sectors showing the strongest correlations. The correlation between RNFL and VFS strengthens as the time from surgical intervention increases.

Bariatric surgery for the treatment of idiopathic intracranial hypertension

Object

The purpose of this study was to review the literature on the effectiveness of bariatric surgery for obese patients with idiopathic intracranial hypertension (IIH) with regard to both symptom resolution and resolution of visual deficits.

Methods

The published literature was reviewed using manual and electronic search techniques. Data from each relevant manuscript were gathered, analyzed, and compared. These included demographic data, pre- and postoperative symptoms, pre- and postoperative visual field deficits, bariatric procedure type, absolute weight loss, changes in body mass index, and changes in CSF opening pressure.

Results

Eleven relevant publications (including 6 individual case reports) were found, reporting on a total of 62 patients. The Roux-en-Y gastric bypass was the most common bariatric procedure performed. Fifty-six (92%) of 61 patients with recorded postoperative clinical history had resolution of their presenting IIH symptoms following bariatric surgery. Thirty-four (97%) of 35 patients who had undergone pre- and postoperative funduscopy were found to have resolution of papilledema postoperatively. Eleven (92%) of 12 patients who had undergone pre- and postoperative formal visual field testing had complete or nearly complete resolution of visual field deficits, and the remaining patient had stabilization of previously progressive vision loss. In 13 patients both pre- and postoperative CSF pressures were recorded, with an average postoperative pressure decrease of 254 mm H2O. Changes in weight loss and body mass index varied depending on the reported postoperative follow-up interval.

Conclusions

The published Class IV evidence suggests that bariatric surgery may be an effective treatment for IIH in obese patients, both in terms of symptom resolution and visual outcome. Prospective, controlled studies are necessary for better elucidation of its role.

Perioperative posterior ischemic optic neuropathy: review of the literature

Posterior ischemic optic neuropathy (PION) is an uncommon cause of perioperative visual loss. Perioperative PION has been most frequently reported after spinal surgery and radical neck dissection. The visual loss typically presents immediately after recovery from anesthesia, although it may be delayed by several days. Visual loss is often bilateral and profound with count fingers vision or worse. The examination findings are consistent with an optic neuropathy; however the funduscopic examination is initially normal. The cause is unknown, although patient-specific susceptibility to perioperative hemodynamic derangements is likely. No treatment has proven to be effective. The prognosis for visual recovery is generally poor.

Recovery of visual function in patients with biopsy-proven giant cell arteritis

OBJECTIVE

To assess the visual function of patients with giant cell arteritis (GCA) who had visual loss from either anterior ischemic optic neuropathy (AION) or central retinal artery occlusion and had a subsequent improvement in visual acuity after treatment with corticosteroids.

DESIGN

Retrospective, observational case series.

PARTICIPANTS

Thirty-two consecutive patients with biopsy-proven GCA treated at one institution between January 1992 and December 1997.

INTERVENTION

Treatment with intravenous methylprednisolone 250 mg every 6 hours for 3 days, followed by oral prednisone 1 mg/kg daily for at least 4 weeks duration.

MAIN OUTCOME MEASURES

The number of patients with an improvement in visual acuity after treatment with intravenous methylprednisolone; neuro-ophthalmic evaluation, including visual acuity, funduscopy, and visual field examination of these patients.

RESULTS

Improvement in visual acuity occurred in 5 of 39 eyes (13%) with visual loss from biopsy-proven GCA, and all 5 patients had AION. Despite the improvement of visual acuity in these 5 patients, perimetry revealed marked constriction of the visual field in each affected eye.

CONCLUSIONS

The prognosis for visual improvement in GCA is poor. Although an improvement in visual acuity occurred in 5 of our patients, marked constriction of the visual field was present in all of them.

Occurrence of Cerebral Venous Sinus Thrombosis in Patients with Presumed Idiopathic Intracranial Hypertension

PURPOSE

To report the rate of occurrence of cerebral venous sinus thrombosis (CVST) in patients with presumed idiopathic intracranial hypertension (IIH).

DESIGN

Retrospective chart review.

PARTICIPANTS

All patients diagnosed with papilledema from November 1, 2002, through October 31, 2003, at 3 tertiary care neuro-ophthalmology centers.

METHODS

Consecutive patients with a diagnosis of papilledema from 3 tertiary care neuro-ophthalmology centers were identified. Patients with space-occupying lesions, hydrocephalus, or meningitis were excluded. The remaining patients were evaluated with lumbar puncture, magnetic resonance imaging (MRI), and magnetic resonance venography (MRV).

MAIN OUTCOME MEASURES

The rate of occurrence of CVST in patients with presumed IIH.

RESULTS

One hundred thirty-one patients with papilledema were identified. Excluding patients with mass lesions, meningitis, or hydrocephalus, the occurrence of CVST was 10 (9.4%) of 106 patients with presumed IIH. Two additional patients had a diagnosis of suspected CVST. Cerebral venous sinus thrombosis was diagnosed in 1 of the 10 patients with MRI alone, whereas it was evident in all 10 patients with MRV. Underlying risk factors for CVST were identified in 9 of 10 patients.

CONCLUSIONS

Cerebral venous sinus thrombosis accounts for 9.4% of patients with presumed IIH in 3 tertiary care neuro-ophthalmology services. Magnetic resonance venography in combination with MRI is recommended to identify this subgroup of patients.

Thrombocytosis in patients with biopsy-proven giant cell arteritis

OBJECTIVE

To compare the platelet counts, complete blood counts, and Westergren sedimentation rates (WESR) of patients with a biopsy positive for giant cell arteritis (GCA) with those of patients with negative biopsies.

DESIGN

Retrospective, case-control series.

METHOD

The medical records of 91 consecutive patients who underwent temporal artery biopsy for possible GCA, over an 8-year period, were reviewed.

MAIN OUTCOME MEASURES

Values obtained for the complete blood counts, including platelet counts, WESR, and biopsy results of 91 consecutive patients undergoing temporal artery biopsy were analyzed.

RESULTS

The mean platelet count of 47 patients with positive temporal artery biopsies (433 x 10(3)/microl) was significantly higher than that of 44 patients with negative temporal artery biopsies (277 x 10(3)/microl), P < 0.0001. There was no statistically significant difference in the mean WESR between the biopsy-positive (82 mm/hour) and biopsy-negative (70 mm/hour) groups, P = 0.12. The sensitivity of an elevated WESR for biopsy-positive patients was greater (79%; 95% confidence interval [CI], 64%-89%) than that of an elevated platelet count (57%; 95% CI, 42%-72%). However, the specificity (91% [95% CI, 78%-97%] versus 27% [95% CI, 15%-43%]), positive predictive value (87% [95% CI, 70%-96%] versus 54% [95% CI, 41%-66%]), and negative predictive value (67% [95% CI, 53%-78%] versus 55% [95% CI, 32%-76%]) favored an elevated platelet count compared with WESR, or to the combination of platelets and WESR, as a better test for diagnosing GCA in the 91 patients studied. The area under the receiver operating characteristic function for platelets (0.72) was greater than that for WESR (0.59) or the combination of platelets and WESR (0.65).

CONCLUSIONS

In patients suspected of having GCA, an elevated platelet count greater than 400 x 10(3)/microl is a useful marker of a positive temporal artery biopsy.

Ischemic optic neuropathy as the first manifestation of elevated cholesterol levels in young patients

PURPOSE

To investigate the relationship between idiopathic nonarteritic ischemic optic neuropathy (NAION) and serum lipid levels in patients </= 50 years of age.

DESIGN

Case-control study.

PARTICIPANTS

Thirty-seven consecutive patients with NAION and 74 age- and gender-matched comparison patients.

METHODS AND MAIN OUTCOME MEASURES

Serum lipid levels and the presence of several historical diseases and exposures were abstracted from the medical records in cases and controls.

RESULTS

The mean total cholesterol level was significantly increased in patients with NAION compared with controls (235.4 vs. 204.0 mg/dl, P < 0.001). The odds ratio of having high blood cholesterol (>/= 240 mg/dl) with NAION was 3.3 (95% confidence interval, 1.4-7.8), and the likelihood increased when the comparison was restricted to nondiabetic patients. Diabetes mellitus was more common in cases than controls (P = 0.027), but systemic hypertension was not significantly different (P = 0.63). No patient (0 of 24) had a magnetic resonance imaging study consistent with optic neuritis or central nervous system demyelination. Visual improvement was uncommon.

CONCLUSIONS

This study demonstrates that hypercholesterolemia is associated with NAION in younger patients. NAION may be the first manifestation of a lipid disorder, a previously unrecognized syndrome. These patients have experienced a focal, microvascular central nervous system ischemic event at a relatively young age. Aggressive treatment of lipid abnormalities in these patients may be warranted.

Acute demyelinating optic neuritis

Acute demyelinating optic neuritis associated with multiple sclerosis (MS) is the most common cause of inflammation of the optic nerve. The Optic Neuritis Treatment Trial (ONTT) has provided important clinical data on the use of corticosteroids, and demonstrated that patients with characteristic inflammatory lesions within the brain on magnetic resonance imaging had a greater chance of developing clinically definite MS (CDMS). The current approach to patients with optic neuritis has been modified by the results of the Controlled High-Risk Subjects Avonex Multiple Sclerosis Prevention Study (CHAMPS). Patients with an initial clinical episode of demyelination (optic neuritis, incomplete transverse myelitis, or brain-stem/cerebellar syndrome) and at least two characteristic demyelinating lesions within the brain were randomized to receive interferon beta-1a or placebo after initial treatment with intravenous corticosteroids. At the 3-year point patients treated with interferon beta-1a showed a 50% less risk of CDMS. The results of this study have set the standard for patients with a first bout of demyelinating optic neuritis.

Vitamin A deficiency in patients with a remote history of intestinal surgery

BACKGROUND/AIMS

Vitamin A deficiency, often presenting with nyctalopia, has been described in a number of patients with malabsorption as a result of intestinal bypass surgery and, more recently, bariatric surgery. In these reports vitamin A deficiency developed within several years of gastric or intestinal surgery. Three patients who developed decreased vision from vitamin A deficiency more than 18 years after their intestinal surgery are reported.

METHODS

A retrospective review of the clinical findings of all patients diagnosed with vitamin A deficiency, as confirmed by serological testing, over the past year in a single neuro-ophthalmic practice.

RESULTS

Four patients with vitamin A deficiency were seen, three of whom had intestinal surgery more than 18 years before the development of visual symptoms.

CONCLUSION

The authors suggest that vitamin A deficiency should be suspected in patients with unexplained decreased vision and a history of intestinal surgery, regardless of the timing of the surgical procedure.

Decreased retinal nerve fibre layer thickness detected by optical coherence tomography in patients with ethambutol-induced optic neuropathy

BACKGROUND

It is difficult to assess the degree of optic nerve damage in patients with ethambutol-induced optic neuropathy, especially just after the onset of visual loss, when the optic disc typically looks normal.

AIM

To evaluate changes in retinal nerve fibre layer thickness (RNFLT) using optical coherence tomography (OCT) in patients with optic neuropathy within 3 months of cessation of ethambutol treatment.

DESIGN

A retrospective observational case series from a single neuro-ophthalmology practice.

METHODS

8 patients with a history of ethambutol-induced optic neuropathy were examined within 3 months after stopping ethambutol treatment. All patients underwent a neuro-ophthalmologic examination, including visual acuity, colour vision, visual fields and funduscopy. OCT was performed on both eyes of each patient using the retinal nerve fibre layer analysis protocol.

RESULTS

The interval between cessation of ethambutol treatment and the initial visit ranged from 1 week to 3 months. All patients had visual deficits characteristic of ethambutol-induced optic neuropathy at their initial visit, and the follow-up examination was performed within 12 months. Compared with the initial RNFLT, there was a statistically significant decrease in the mean RNFLT of the temporal, superior and nasal quadrants (p = 0.009, 0.019 and 0.025, respectively), with the greatest decrease in the temporal quadrant (mean decrease 26.5 mum).

CONCLUSIONS

A decrease in RNFLT is observed in all quadrants in patients with ethambutol-induced optic neuropathy who have recently discontinued the medication. This decrease is most pronounced in the temporal quadrant of the optic disc.

Outcomes after laser therapy for threshold retinopathy of prematurity

OBJECTIVE

To determine the anatomic outcomes of eyes treated with laser photocoagulation for threshold retinopathy of prematurity and to identify potential risk factors for unfavorable outcomes after treatment.

DESIGN

Retrospective, noncomparative case series.

INTERVENTION

Photocoagulation of the peripheral avascular retina with an argon or diode laser indirect ophthalmoscope.

PARTICIPANTS

One hundred twenty eyes of 81 infants with threshold retinopathy of prematurity treated with laser photocoagulation from 1989 through 1997 with at least 12 months of follow-up after treatment.

MAIN OUTCOME MEASURES

The principal outcome was the presence of an unfavorable anatomic outcome defined as a retinal detachment, macular fold, or retrolental tissue.

RESULTS

One hundred nine of 120 eyes (91%) had favorable outcomes. Eleven eyes (9%) had retinal detachments, and 1 of the 11 also had retrolental tissue. Zone 1 eyes appeared to be 3.3 times more likely to have an unfavorable outcome compared with zone 2 eyes, but the 95% confidence interval (0.8-14.5) did not support this statistically. Twenty-four of 109 eyes (22%) experienced dragging of the temporal vessels. Those with zone 1 disease were 13.7 times more likely to experience temporal dragging compared with zone 2 eyes (95% confidence interval, 3.3-57.2).

CONCLUSIONS

After laser photocoagulation for threshold retinopathy of prematurity, 91% of eyes had a favorable anatomic outcome. Compared with zone 2 eyes, zone 1 eyes may be more likely to have temporal dragging of the retinal vessels. Laser therapy is effective in the treatment of threshold retinopathy of prematurity.

Nonarteritic anterior ischemic optic neuropathy

Nonarteritic anterior ischemic optic neuropathy refers to an idiopathic ischemic process of the anterior portion of the optic nerve. The typical presentation is sudden and painless visual loss with examination features of an optic neuropathy. Among the various associated risk factors are optic disc morphology, advanced age, systemic arterial hypertension, diabetes mellitus, and nocturnal hypotension. Currently, there is no proven effective long-term treatment for this disorder.

Cortical visual impairment in children

PURPOSE OF REVIEW

Cortical visual impairment is rapidly becoming a leading cause of visual loss in children in developed countries predominately because of the improved survival rates of premature infants over the past decade.

RECENT FINDINGS

Most cases of cortical visual impairment arise from hypoxic ischemic injury to watershed areas of the brain. In the preterm infant the watershed areas are in the subcortex around the ventricles, while in the term infant the watershed areas are between the major arteries with injury to the subcortex and cortex. Therefore, preterm and term injury will manifest different ocular and visual system abnormalities as a result of this damage. Cognitive visual dysfunction, a type of cortical visual impairment, may occur in cases of damage to the peristriate cortex (association areas of the brain). The anterior visual pathways may also be damaged in a retrograde, transsynaptic fashion in cases of cortical visual impairment.

SUMMARY

Cortical visual impairment is a prevalent cause of visual loss in children. It encompasses a wide range of visual disabilities from no light reception to normal visual acuity with cognitive visual dysfunction.

Chiasmal syndromes

PURPOSE OF REVIEW

This review of the more recent literature and testing strategies in patients with chiasmal syndromes focuses on the clinical evaluation and management of these patients. Visual loss is often the initial manifestation of disorders involving the optic chiasm. Hemianopic defects and preferential involvement of the temporal visual field are the earliest and most common visual deficits. Progression of the lesion may cause compression of adjacent structures, including the optic nerves and cavernous sinuses, and may result in more profound visual loss, ocular motor deficits, and hypopituitarism.

RECENT FINDINGS

Although a number of modalities have been used to assess visual function in patients with chiasmal disorders, perimetry remains the most effective means of detecting and following the visual deficit.

SUMMARY

Most chiasmal syndromes can be categorized as intrinsic (thickening of the chiasm itself) or extrinsic (compression of the chiasm from an adjacent structure). Magnetic resonance imaging is the best mode of neuroimaging for most chiasmal lesions and may also provide clues to the etiology of an isolated chiasmal syndrome.

Amiodarone induced optic neuropathy

AIM

To determine the clinical features of amiodarone induced optic neuropathy, which may help distinguish it from non-arteritic anterior ischaemic optic neuropathy.

METHODS

Retrospective observational case series of patients diagnosed with amiodarone induced optic neuropathy at the neuro-ophthalmology service from March 1998 to February 2001. Amiodarone was discontinued after discussion with the patient's cardiologist. Visual acuity, colour vision, automated perimetry, and funduscopy were performed on initial and follow up examinations.

RESULTS

Three patients with amiodarone induced optic neuropathy presented with mildly decreased vision, visual field defects, and bilateral optic disc swelling. Upon discontinuing the medication, visual function and optic disc swelling slowly improved in all three patients.

CONCLUSION

Amiodarone induced optic neuropathy can present with visual dysfunction, and is typically a bilateral process. Upon discontinuation of amiodarone, slow resolution of optic disc swelling occurs and visual function improves in some patients.

Optic Neuropathy Associated With Linezolid Treatment

Two patients undergoing long-term treatment with linezolid for pneumonia had decreased visual acuity, dyschromatopsia, and cecocentral scotomas characteristic of toxic optic neuropathy. Visual function slowly recovered 3 to 4 months after discontinuation of the antibiotic treatment in both patients. Toxic optic neuropathy may occur from linezolid. Early withdrawal of the antibiotic may be associated with visual recovery.

Presentation and Progression of Papilledema in Cerebral Venous Sinus Thrombosis

PURPOSE

To determine the natural history and visual outcomes of papilledema in cerebral venous sinus thrombosis (CVST).

DESIGN

Retrospective observational case series.

METHODS

This multicenter study included 7 tertiary care neuro-ophthalmology clinics. Sixty-five patients with CVST were identified who received serial eye examinations with documented papilledema from 2008-2016. Outcome measures included time from diagnosis to papilledema documentation, papilledema progression, time to papilledema resolution, treatment interventions and final visual outcomes.

RESULTS

Papilledema was present on initial presentation in 54% of patients or detected later during the course of the disease in 46% of patients. The average time from CVST diagnosis to papilledema documentation was 29 days with a mean (SD) initial Frisén grade of 2.7 (1.3). In 21.5% of cases, papilledema progressed over an average of 55.6 (56.6) days. Time to papilledema resolution was approximately 6 months. Final visual acuity ranged from 20/20 to light perception, with 40% of patients having residual visual field defects on standard automated perimetry. Frisén grade ≥3 (odds ratio [OR] 10.21, P < .0053) and cases with worsening papilledema (3.5, P < .043) were associated with permanent visual field deficits.

CONCLUSIONS

Our study indicates the importance of serial ophthalmic evaluation in all cases of CVST. Follow-up fundoscopy is critical given that a subset of cases can show delayed onset and/or worsening of papilledema with time. Specifically, we recommend an ophthalmic examination at the time of initial diagnosis, with repeat examination within a few weeks and further follow-up depending on the level of papilledema or vision changes.

Embolic central retinal artery occlusion detected by orbital color Doppler imaging

OBJECTIVE

To describe the detection of emboli to the retrobulbar circulation using orbital color Doppler imaging in patients with central retinal artery occlusions (CRAO) without visible retinal emboli.

DESIGN

Noncomparative, retrospective, observational case series.

PATIENTS AND METHODS

Twenty-nine patients with CRAO, without funduscopic evidence of embolic material within the retinal arterioles, underwent neuroophthalmic examination and evaluation with orbital color Doppler imaging.

MAIN OUTCOME MEASURES

The detection of retrobulbar plaques using orbital color Doppler imaging.

RESULTS

Nine of 29 (31%) patients with CRAO demonstrated hyperechoic retrobulbar plaques. All nine patients had visual acuity of counting fingers or worse at presentation. Six of the nine patients (67%) had a history of hypertension, and seven (78%) had coronary artery disease as vascular risk factors for arterial occlusive disease. Two of the nine patients (22%) subsequently died from cardiac-related events.

CONCLUSIONS

This study demonstrates that orbital color Doppler imaging is an important diagnostic procedure for establishing embolism as the cause of CRAO when no emboli are visible in the retinal circulation. This noninvasive technology enables prompt differentiation of embolic disease from arterial occlusion caused by intrinsic atherosclerosis, vasospasm, or vasculitis from giant cell arteritis. Recognition of emboli has important management implications for these patients.

Is normal tension glaucoma actually an unrecognized hereditary optic neuropathy? New evidence from genetic analysis

Normal tension glaucoma and dominant optic atrophy share many overlapping clinical features, and differentiating between these two diseases is often difficult. The gene responsible for dominant optic atrophy is the OPA1 gene located on chromosome 3. This gene encodes for a protein product that is involved in mitochondrial metabolic function. Recent genetic linkage analysis of patients with normal tension glaucoma has shown an association with polymorphisms of the OPA1 gene. This association suggests that normal tension glaucoma may actually be a hereditary optic neuropathy with a pathophysiology based in mitochondrial dysfunction.

Macular hole in cat scratch disease

PURPOSE

To report the development of a macular hole as a complication of cat scratch disease.

DESIGN

Case report.

METHODS

A 10-year-old girl was seen with unilateral neuroretinitis from serologically confirmed cat scratch disease. Twelve days later, she developed a macular hole in the involved eye. Fundus photography and optical coherence tomography (OCT) were obtained at presentation and after the development of a macular hole.

RESULTS

Fundus photography and OCT on presentation revealed a nasal neurosensory detachment and multiple inflammatory foci throughout the macula, including a subfoveal lesion. Fundus photography and OCT 12 days later revealed the development of a partial posterior vitreous detachment and a full thickness macular hole.

CONCLUSIONS

Macular hole should be included among posterior segment complications of cat scratch disease. In this case, the macular hole was associated with partial vitreous detachment and a preexisting subfoveal lesion, likely representing an inflammatory focus.

Posterior ischemic optic neuropathy after hemodialysis

PURPOSE

To report a case of visual loss from posterior ischemic optic neuropathy (PION) after hemodialysis.

DESIGN

Observational case report.

METHODS

Neuro-ophthalmic examination, neuro-imaging including computed tomography (CT) scan, magnetic resonance imaging (MRI) of the head and orbits, and magnetic resonance angiography (MRA) of the neck and cerebral vasculature, as well as electrophysiologic testing including electroretinogram (ERG) and visually evoked response (VER) were performed.

RESULTS

Acute onset of painless bilateral no light perception vision with absent pupillary response to light and normal funduscopic examination occurred shortly after completion of hemodialysis. Computed tomography scan and MRA results were normal. Magnetic resonance imaging scan showed small vessel ischemic white matter changes. Electroretinogram results were normal and the VER was unrecordable.

CONCLUSIONS

Visual loss after hemodialysis is a rare complication and is associated with anemia and hypotensive events. The visual loss is usually a result of anterior ischemic optic neuropathy. We were unable to find another instance in the literature of visual loss after hemodialysis resulting from PION.

Recurrent microhyphema despite intracapsular fixation of a posterior chamber intraocular lens

A 61-year-old woman experienced multiple episodes of transient visual blurring in her pseudophakic eye, each of which lasted about 1 hour. Repeat examination during a symptomatic episode revealed anterior chamber red blood cells consistent with a microhyphema in the pseudophakic eye despite intracapsular fixation of a posterior chamber intraocular lens (PC IOL). Ultrasound biomicroscopy confirmed intracapsular fixation of the IOL haptics and revealed proximity of the edge of the IOL optic to the inferior pupillary margin in the region of an iridociliary body cyst. Uveitis-glaucoma-hyphema syndrome may occur despite intracapsular fixation of a PC IOL.