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ObjectivesThe objective of this case report was to describe a rare presentation of corkscrew cerebral angiopathy presenting as subarachnoid hemorrhage (SAH).MethodsWe present a young woman who presented with a thunderclap headache, found to have a nonaneurysmal SAH.ResultsCerebral angiogram revealed corkscrew angiopathy in medium-sized vessels and multiple micro-occlusions with collateralization. No intracranial aneurysm was detected. Extensive workup for vasculitis and genetic causes for vasculopathy was unrevealing. The patient had no neurologic deficits, and her symptoms resolved.DiscussionThis is an extremely rare presentation of subarachnoid hemorrhage due to corkscrew angiopathy.

Background Superior orbital fissure syndrome (SOFS) is a rare constellation of findings consisting of ophthalmoplegia, ptosis, a fixed dilated pupil, forehead anesthesia, and loss of the corneal reflex. This syndrome, though rare, is most often encountered in trauma with individuals sustaining a facial fracture. Case Report We present a case of a young woman who was diagnosed with SOFS after a fall in her house, hitting her face on a nightstand. Treatment consisted of high-dose i.v. steroids followed by a taper with close follow-up in the Ophthalmology clinic. We provide a brief review of SOFS, including treatment considerations and follow-up. Why Should an Emergency Physician Be Aware of This? SOFS can be easily overlooked in an individual presenting to the emergency department after facial trauma with proptosis. However, a thorough examination of the eye, visual acuity, and intraocular pressure will focus the physician on SOFS rather than the need for immediate decompression via lateral canthotomy. This report describes a traumatic cause of SOFS, the pathophysiology and treatment, and summarizes existing literature.

Introduction/Background: A rough, visual estimate of pupil size is used in grading the severity of opioid withdrawal. Few studies have examined the clinical utility of more precise automated pupillometry measurements. Methods: This prospective cohort study enrolled 27 patients receiving opioid agonist therapy (OAT) to treat cravings or withdrawal during an acute hospitalization. Six sets of automated pupillometry measurements were obtained at regular intervals before and after administration of OAT. Clinical Opiate Withdrawal Scale measurements were performed pre and post OAT. Primary outcomes included pupil size in dark and bright illumination (mm). Latency of the pupillary light response (s), constriction and dilation velocity (mm/s), and percent constriction (%) were secondary outcomes. Results: The mean predosing pupil size in dark and bright illumination was 4.33 ± 1.40 mm and 2.96 ± 0.79 mm, respectively. A significantly decreased mean pupil size was first detected at 15 minutes postdosing (4.01 ± 1.34 mm, P = 0.0115 for dark illumination; 2.71 ± 0.72 mm, P = 0.0003 for bright illumination) and this reduction in pupil size persisted at later postdosing timepoints. Those with Clinical Opiate Withdrawal Scale

Introduction Residency programs receive an institutional keyword report following the annual Ophthalmic Knowledge Assessment Program (OKAP) examination containing the raw number of incorrectly answered questions. Programs would benefit from a method to compare relative performance between subspecialty sections. We propose a technique of normalizing the keyword report to determine relative subspecialty strengths and weaknesses in trainee performance. Methods We retrospectively reviewed our institutional keyword reports from 2017 to 2019. We normalized the percentage of correctly answered questions for each postgraduate year (PGY) level by dividing the percent of correctly answered questions for each subspecialty by the percent correct across all subsections for that PGY level. We repeated this calculation for each PGY level in each subsection for each calendar year of analysis. Results There was a statistically significant difference in mean performance between the subspecialty sections (p = 0.038). We found above average performance in the Uveitis and Ocular Inflammation section (95% confidence interval [CI]: 1.02–1.18) and high variability of performance in the Clinical Optics section (95% CI: 0.76–1.34). Discussion The OKAP institutional keyword reports are extremely valuable for residency program self-evaluation. Performance normalized for PGY level and test year can reveal insightful trends into the relative strengths and weaknesses of trainee knowledge and guide data-driven curriculum improvement.

Purpose: This work aims to determine whether patient satisfaction with oral sedation is noninferior to intravenous (IV) sedation in vitrectomy surgery. Methods: This prospective, randomized, double-masked, noninferiority clinical trial measured patient satisfaction in 84 participants receiving oral or IV sedation during vitrectomy surgery under monitored anesthesia care. Patients were excluded if they were unable to receive benzodiazepines. Results: The primary outcome was patient satisfaction. Secondary outcomes included surgeon and anesthesia provider satisfaction, need for supplemental anesthesia, and surgical complications. Among the 84 patients (46 [54.8%] men; mean [SD] age, 57.0 [12.7 years]), mean patient satisfaction scores were 5.22 ± 0.81 (range, 3.08-6; scale 1-6) with oral and 5.25 ± 0.63 (range, 3.83-6; scale 1-6) with IV sedation. With an a priori noninferiority margin of 0.5 and a difference in mean scores between the groups of 0.03 (1-tailed 95% CI, infinity to 0.29), our results demonstrated the noninferiority of oral sedation ( P = .002). There were no significant differences in surgeon or anesthesia satisfaction or major intraoperative complications. Five patients receiving oral (11.9%) and 3 receiving IV (7.1%) sedation required supplemental IV sedation (difference, 4.8%; P = .46). Conclusions: Patient satisfaction for oral sedation was noninferior to IV sedation for vitrectomy surgery.

PURPOSE: To describe and distinguish clinical phenotypes with the overlapping feature of optic atrophy caused by distinct mutations in the same gene, OPA3. We report 3 affected siblings in a consanguineous family harboring a novel OPA3 mutation causing 3-methylglutaconic aciduria type III with optic atrophy. METHODS: Retrospective case series. RESULTS: Three siblings (2 male, 1 female) among 6 children in a consanguineous Afghani family developed decreased vision from early childhood. Both parents and all extended family members were unaffected. All 3 affected siblings suffered from severe visual impairment ranging from visual acuities of 20/150 to counting fingers. All had spastic lower extremity weakness and ataxia. Two of the three affected siblings also had a history of seizures, and the female sibling had limited cognition with diffuse atrophic changes on brain MRI. Two of the three individuals also had migraine-like headaches. Urine organic acid analysis revealed mildly elevated 3-methylglutaconic acid for the male siblings. Whole exome sequencing and subsequent PCR confirmation revealed a novel variant in OPA3 (intron1, c.142+2_142+3dupTG), affecting the consensus sequence of the splice site, for which all 3 clinically affected siblings were homozygous. DISCUSSION: Mutations in OPA3 can cause optic atrophy in a dominant pattern of inheritance associated with cataract or in a recessive pattern associated with spastic paresis and ataxia. The novel recessive variant and clinical presentations described herein further support how different mutation types affecting OPA3 can produce distinct clinical phenotypes and underscore the critical and susceptible role of mitochondrial health in optic nerve function.

Purpose To determine whether patient satisfaction with oral sedation is noninferior to intravenous sedation for cataract surgery. Design Prospective, randomized, double-masked clinical trial. Participants A volunteer sample of patients 18 years or older from diverse backgrounds scheduled for cataract surgery. Patients who were allergic to benzodiazepines, older than 70 years with a failed delirium screening questionnaire, pregnant or nursing, using a medication inhibiting cytochrome 450 3A, or intoxicated on the day of surgery were excluded. Methods Patients were randomized to receive either oral triazolam with intravenous placebo or intravenous midazolam with oral placebo before surgery. Main Outcomes Measures The primary outcome was patient satisfaction, measured by a survey administered on postoperative day 1. Secondary outcomes included surgeon and anesthesia provider satisfaction, need for supplemental anesthesia, and surgical complications. Results Among the 85 patients (42 men [49.4%]; mean age, 65.8 years; standard deviation, 9.5 years) completing the study, the mean satisfaction score was 5.34±0.63 (range, 3.75–6) in the oral sedation group and 5.40±0.52 (range, 4–6) in the intravenous group. With an a priori noninferiority margin of 0.5 and a difference in mean scores between the 2 groups of 0.06 (1-tailed 95% confidence interval [CI], –infinity to 0.27), our results demonstrate noninferiority of oral sedation with a P value of 0.0004. Surgeon and anesthesia provider satisfaction was similar between the 2 groups. Intraoperative complications occurred in 16.7% in the oral group and 9.3% in the intravenous group (difference, 7.4%; 95% CI, –6.9% to 21.6%; P = 0.31). The only major intraoperative complication—a posterior capsular tear—occurred in the intravenous group. Eight patients in the oral group (19.0%) and 3 in the intravenous group (7.0%) received supplemental intravenous sedation (difference, 12.1%; 95% CI, –2.0% to 26.2%; P = 0.097). Conclusions The use of oral sedation in cataract surgery has been suggested as a cost- and space-saving measure, potentially allowing the transition of some patients from an operating to procedure room or office-based setting. We report the noninferiority of oral compared with intravenous sedation for cataract surgery in a diverse patient population in terms of patient satisfaction.

To describe the clinical characteristics and visual and ocular motor outcomes of a large cohort of pediatric patients treated for tumors of the posterior cranial fossa.The medical records of all patients with posterior fossa tumors evaluated by the ophthalmology services at two large tertiary care academic hospitals between 2005 and 2011 were reviewed retrospectively. Data abstracted for each study patient included demographic information, presenting signs and symptoms, pathologic diagnosis, and results of the most recent ophthalmology examination.A total of 139 patients were included. Visual outcomes were categorized as "good" (bilateral acuity of 20/20-20/40) in 101 patients (72.7%), "fair" (20/40-20/200 in one or both eyes) in 12 patients (8.6%), or "poor" (20/200 in one or both eyes) in 9 patients (6.5%). Patients with medulloblastoma and ependymoma had a significantly greater risk of a poor or fair visual outcome than those with juvenile pilocytic astrocytoma (both P 0.05), independent of age and sex. Thirty-two patients (23.0%) developed nystagmus, and 59 patients (42.4%) developed strabismus. Twenty-four patients (17.3%) underwent eye muscle surgery for persistent strabismus.The majority of patients had good visual outcomes, although ocular motor abnormalities were common. Tumor type was a significant risk factor for permanent vision loss.

To summarize the visual and oculomotor outcomes in children with prenatal opioid exposure and review the effects of opioids on the developing central nervous system.Animal models and imaging studies in children suggest that prenatal opioid exposure may affect neuronal survival and result in delayed maturation of white matter tracts and decreased volumes in certain brain areas. Visual evoked potential testing in children demonstrates delayed maturation of the afferent visual system in opioid-exposed groups compared with controls, though 'catch-up' development is seen with longitudinal follow-up. Strabismus and nystagmus are also more common in exposed children, and these findings appear to persist.As rates of opioid dependence and prenatal opioid exposure continue to increase, it is important to evaluate the short-term and long-term effects of opioids on the developing visual system. An understanding of these risks is important when counseling the parents or guardians of opioid-exposed children, though larger studies with more long-term follow-up will improve our prognostic abilities.

The pupillary exam in the pediatric population is a vital part of any clinician's workup. In the right clinical setting, pupillary abnormalities such as anisocoria, light-near dissociation, an afferent pupillary defect, and paradoxic pupillary constriction in the dark can be red flags that trigger further examination and workup. Through both careful physical examination and detailed history-taking and observation, potentially vision- and life-threatening conditions can be detected.

Background The Basic and Clinical Science Course (BCSC) is the primary educational curriculum for ophthalmology resident physicians in the United States. The Ophthalmic Knowledge Assessment Program (OKAP) examination is an annual evaluation completed by residents that is based primarily on the BCSC curriculum. First-year ophthalmology residents are encouraged to complete the 13 volume BCSC series in preparation for the OKAP examination while balancing a steep clinical learning curve and substantial call schedule. By calculating the daily time commitment necessary to read each volume in the series, we hope to help residents create a realistic study plan to compete the entire BSCS series before the OKAP examination. Methods We determine the word counts of each volume using an electronic copy of the 2018–2019 BCSC series. We include all text sections and legends, and we exclude all figures and tables. We calculate the time per day of dedicated reading required to complete a goal number of BCSC books between the start of ophthalmology residency (postgraduate year 2 [PGY2]) and the OKAP examination by developing a formula that is a function of self-assessed reading speed. Results A first-year ophthalmology (PGY2) resident with an average reading speed of 250 words per minute must read for 25.0 minutes per day to complete the entire BCSC series before the OKAP examination. If studying is initiated at the beginning of intern (PGY1) year, the resident must read for 10.2 minutes per day. We introduce a formula and provide a table to guide residents on the amount of time needed to dedicate to reading the BCSC each day as a function of self-assessed reading speed. Discussion Completion of all volumes of the BCSC requires a daily commitment with little room for missed sessions. The commitment is substantially more realistic if initiated during the PGY1 year; thus, residency programs should encourage an early start to OKAP preparation. We hope with a better understanding of the daily time commitment involved in completing the BCSC series, ophthalmology residents will be able to develop more successful study plans.

BACKGROUND AND PURPOSE: Intraocular silicone oil injection has been used to treat complicated retinal detachments, and recently its retrolaminar and intracranial migration has been reported. The purpose of this study was to document the prevalence of posterior migration of intraocular silicone oil on head CT and describe the clinical and radiologic findings. MATERIALS AND METHODS: This retrospective study included 57 patients with intraocular silicone oil injection who underwent unenhanced head CT between November 2008 and July 2018. All images were visually evaluated for subretinal and retrolaminar migration of intraocular silicone oil involving the anterior visual pathway (optic nerve, optic chiasm, and optic tract) and the ventricular system. Attenuation values of those structures were measured and compared with those of the contralateral or adjacent normal structures. RESULTS: We detected subretinal and retrolaminar silicone oil migration in 7 of the 57 patients (12%), noting silicone oil at the optic nerve head (n = 2), retrolaminar optic nerve (n = 5), optic chiasm (n = 3), optic tract (n = 3), and in the lateral ventricles (n = 1). Attenuation values of the structures with silicone oil migration were significantly higher than those of the control regions (optic nerve head, 69.2 ± 12.4 vs 29.8 ± 10.2 HU, P < .001; retrolaminar optic nerve, 59.9 ± 11.6 vs 30.9 ± 8.6 HU, P < .001; optic chiasm, 74.2 ± 11.0 vs 25.6 ± 6.9 HU, P < .001; optic tract, 70.1 ± 4.7 vs 28.7 ± 7.2 HU, P < .001). No significant ophthalmic or neurologic complications were documented in the patients with silicone oil migration. CONCLUSIONS: Subretinal and retrolaminar migration of intraocular silicone oil is common. Although there were no apparent complications associated with silicone oil migration, the radiologist and clinician should be aware of this phenomenon.

Non-arteritic anterior ischemic optic neuropathy (NAION) is a relatively common optic neuropathy in adults over the age of 50, typically causing sudden, painless, unilateral vision loss and always resulting in swelling of the optic nerve head. Though several anatomic and vascular risk factors have been identified, much remains unknown about its pathophysiology and there is no proven treatment. This article reviews the risk factors, clinical presentation, and therapies that have been investigated for NAION. In addition, we provide an update from recent rodent and primate models, which offer new insight into the pathophysiology of this disease and provide a platform for treatment trials.

We report the case of a patient who developed the uveitis-glaucoma-hyphema (UGH) syndrome secondary to extensive fibrosis (Soemmerring ring) around the haptics of the single-piece intraocular lens (IOL) in the capsular bag. The development of significant capsule fibrosis caused the IOL to tilt out of the iris plane, leading to haptic-iris and haptic-ciliary body chafing. The mechanisms described should prompt clinicians to consider the UGH syndrome even in the setting of a single-piece IOL properly placed in the capsular bag. Anterior segment imaging with ultrasound biomicroscopy can be used to evaluate the position of the IOL haptics in suspected cases.

To determine whether patient satisfaction with oral sedation is noninferior to intravenous sedation for cataract surgery.Prospective, randomized, double-masked clinical trial.A volunteer sample of patients 18 years or older from diverse backgrounds scheduled for cataract surgery. Patients who were allergic to benzodiazepines, older than 70 years with a failed delirium screening questionnaire, pregnant or nursing, using a medication inhibiting cytochrome 450 3A, or intoxicated on the day of surgery were excluded.Patients were randomized to receive either oral triazolam with intravenous placebo or intravenous midazolam with oral placebo before surgery.The primary outcome was patient satisfaction, measured by a survey administered on postoperative day 1. Secondary outcomes included surgeon and anesthesia provider satisfaction, need for supplemental anesthesia, and surgical complications.Among the 85 patients (42 men [49.4%]; mean age, 65.8 years; standard deviation, 9.5 years) completing the study, the mean satisfaction score was 5.34±0.63 (range, 3.75-6) in the oral sedation group and 5.40±0.52 (range, 4-6) in the intravenous group. With an a priori noninferiority margin of 0.5 and a difference in mean scores between the 2 groups of 0.06 (1-tailed 95% confidence interval [CI], -infinity to 0.27), our results demonstrate noninferiority of oral sedation with a P value of 0.0004. Surgeon and anesthesia provider satisfaction was similar between the 2 groups. Intraoperative complications occurred in 16.7% in the oral group and 9.3% in the intravenous group (difference, 7.4%; 95% CI, -6.9% to 21.6%; P = 0.31). The only major intraoperative complication-a posterior capsular tear-occurred in the intravenous group. Eight patients in the oral group (19.0%) and 3 in the intravenous group (7.0%) received supplemental intravenous sedation (difference, 12.1%; 95% CI, -2.0% to 26.2%; P = 0.097).The use of oral sedation in cataract surgery has been suggested as a cost- and space-saving measure, potentially allowing the transition of some patients from an operating to procedure room or office-based setting. We report the noninferiority of oral compared with intravenous sedation for cataract surgery in a diverse patient population in terms of patient satisfaction.

Consider demyelinating disease in the differential diagnosis of cranial nerve III palsy, particularly in a younger patient without typical microvascular risk factors.

Tumors of the posterior fossa represent the most common solid malignancy of childhood and can affect the visual system in several ways. This article outlines the relevant visual anatomy affected by these tumors and reviews the visual and oculomotor outcomes associated with the following 3 most common tumor types—medulloblastoma, juvenile pilocytic astrocytoma, and ependymoma. The available data suggest that the rate of permanent vision loss is low (5.9%-8.3%), with patients having juvenile pilocytic astrocytoma demonstrating the best outcomes. The rate of long-term strabismus (25%-29.1%) and nystagmus (12.5%-18%) is higher and associated with significant morbidity.

We evaluated the diagnostic accuracy of slit-lamp photographs interpreted by telemedicine compared to a conventional clinical examination. A convenience sample of 21 patients with anterior segment disease was enrolled at the Lumbini Eye Institute (LEI) in Bhairahawa, Nepal. An ophthalmologist at the LEI examined each patient and assigned a diagnosis and follow-up interval; this represented the gold standard. An ophthalmic technician also obtained anterior segment photographs of each patient. Slit-lamp photographs and clinical histories were then uploaded to a server for access by three separate readers. These readers, one in Nepal and two in the US, provided a diagnosis and follow-up interval independently. The diagnostic agreement between the examiner and all readers was good (kappa = 0.75, P

The purpose is to summarize treatment strategies in idiopathic intracranial hypertension (IIH), a potentially sight-threatening disease, with a focus on the most current outcome data for venous sinus stenting.Historically, the primary treatment options for medically refractory IIH consisted of either optic nerve sheath fenestration or cerebrospinal fluid diversion procedures. The visual outcomes of these procedures are favorable, though they tend to be associated with a high rate of complication and failure. Recent trials suggest that venous sinus stenting offers both comparable rates of efficacy - with improved papilledema in 97% of patients, resolved headache in 83%, and improved visual acuity in 78% - and improved safety and reliability relative to older surgical techniques.Patients whose sight is threatened by medically refractory IIH must often consider invasive procedures to control their disease. Venous sinus stenting may offer equal efficacy and lower failure and complication rates than traditional surgical approaches such as optic nerve sheath fenestration and cerebrospinal fluid diversion.

Importance The sensitivity of acetylcholine receptor (AChR) antibody testing is thought to be lower in ocular myasthenia gravis (OMG) compared with generalized disease, although estimates in small-scale studies vary. There is little information in the literature about the implications of AChR antibody levels and progression from OMG to generalized myasthenia gravis. Objectives To test the hypothesis that serum AChR antibody testing is more sensitive in OMG than previously reported and to examine the association between AChR antibody levels and progression from OMG to generalized myasthenia gravis. Design, Setting, and Participants A retrospective, observational cohort study was conducted of 223 patients (mean [SD] age, 59.2 [16.4] years; 139 [62.3%] male) diagnosed with OMG between July 1, 1986, and May 31, 2013, at 2 large, academic medical centers. Main Outcomes and Measures Baseline characteristics, OMG symptoms, results of AChR antibody testing, and progression time to generalized myasthenia gravis (if this occurred) were recorded for each patient. Multiple logistic regression was used to measure the association between all clinical variables and antibody result. Kaplan-Meier survival analysis was performed to examine time to generalization. Results Among the 223 participants, AChR antibody testing results were positive in 158 participants (70.9%). In an adjusted model, increased age at diagnosis (odds ratio [OR], 1.03; 95% CI, 1.01-1.04; P = .007) and progression to generalized myasthenia gravis (OR, 2.92; 95% CI, 1.18-7.26; P = .02) were significantly associated with positive antibody test results. Women were less likely to have a positive antibody test result (OR, 0.36; 95% CI, 0.19-0.68; P = .002). Patients who developed symptoms of generalized myasthenia gravis had a significantly higher mean (SD) antibody level than those who did not develop symptoms of generalized myasthenia gravis (12.7 [16.5] nmol/L vs 4.2 [7.9] nmol/L; P = .002). Conclusions and Relevance We demonstrate a higher sensitivity of AChR antibody testing than previously reported in the largest cohort of patients with OMG available to date. Older age, male sex, and progression to generalized myasthenia gravis were significantly associated with a positive antibody test result. In addition, to our knowledge, this is the first report of an association between high AChR antibody levels and progression from OMG to generalized disease.

BACKGROUND Restricted diffusion of water molecules on diffusion-weighted magnetic resonance imaging most commonly associated with acute stroke, has also been described in brain abscess. It has been reported in only one case of sub-retinal abscess. METHODS Review of two cases. RESULTS Two cases of visual loss from subretinal abscess had restricted diffusion in the region of the abscess. In the first case, DWI revealed restricted diffusion in a white mass visible in the posterior retina. In the second case, restricted diffusion was present in an anterior retinal mass invisible by ophthalmoscopy and ultrasound. In combination of restricted diffusion in the cerebrum consistent with septic emboli, these imaging abnormalities allowed earlier treatment that either preserved vision or prevented enucleation.

Little is known about the incidence of isoniazid-associated hepatitis in HIV-infected Africans who receive both isoniazid preventive therapy (IPT) and antiretroviral therapy (ART).To assess the rate of and risk factors for isoniazid (INH)-associated hepatitis in persons living with HIV (PLWH) during IPT.PLWH recruited for a clinical trial received 6 months of open-label, daily, self-administered INH at public health clinics. At screening PLWH were excluded if they had any cough, weight loss, night sweats, or other illness. Alcohol abuse was defined as meeting any CAGE criterion. INH-associated hepatitis (INH-hepatitis) was defined as having either alanine or aspartate aminotransferase greater than 5.0 times the upper limit of normal regardless of symptoms when INH was not excluded as the cause.Of 1,995 PLWH enrolled between 2004 and 2006, 1,762 adhered to at least 4 months of IPT and were analyzed. Nineteen (1.1%) developed hepatitis probably or possibly associated with INH including one death at month 6; 14 of 19 (74%) occurred in months 1-3. Antiretroviral therapy (ART) was received by 480 participants but was not statistically associated with INH-hepatitis (relative risk [RR], 1.56; 95% confidence intervals [CI], 0.62-3.9); those receiving nevirapine had a higher rate (2.0%) than those receiving efavirenz (0.9%; P = 0.34). Although alcohol use did not reach significance (RR, 1.42; 95% CI, 0.57-3.51), meeting at least one CAGE criterion approached statistical significance (RR, 2.37; 95% CI, 0.96-5.84). Neither age greater than 35 years nor the presence of hepatitis B virus core antibody was associated with INH-hepatitis.The observed rates of INH-hepatitis were similar to published data. Six months of IPT, which is recommended by the World Health Organization, was relatively safe in this, the largest cohort of African PLWH. Clinical trial registered with www.clinicaltrials.gov (NCT 00164281).

Purpose To report a case of optic neuropathy and retinopathy from a dose of radiation traditionally thought to be safe to the visual system and discuss strategies for preventing vision loss when using radiation to treat intraocular tumors. Observations A 44-year-old woman presented with new, painless vision loss in the left eye eighteen months after receiving proton beam radiotherapy (20 Gy dose delivered in two 10 Gy fractions) for a uveal metastasis of lung cancer. The dilated funduscopic examination revealed optic disc swelling and retinal hemorrhages and an MRI of the brain and orbits demonstrated enhancement of the left optic nerve head, findings consistent with radiation optic neuropathy (RON) and retinopathy. Risk factors for developing RON included coincident use of oral chemotherapy and relatively large fractionated doses of radiation. Conclusions and importance Though cumulative radiation doses to the anterior visual pathway of less than 50 Gy are traditionally felt to be safe, it is important to consider not just the total exposure but also the size of individual fractions. The single-dose threshold for RON in proton beam treatment has yet to be defined. Our case suggests that fractions of less than 10 Gy should be delivered to minimize the risk of optic nerve injury.