Subjective versus objective refraction in healthy young adults.

PURPOSE: To evaluate objective and subjective refraction differences in healthy young adults. METHODS: Data concerning candidates for the Israeli Air Force Flight Academy, as well as active air force pilots in all stages of service who underwent a routine health checkup between the years 2018 and 2019 were retrospectively analyzed. Objective refraction measured using a single autorefractometer was compared with subjective refraction measured by an experienced military optometrist during the same visit. The results were converted to power vectors (spherical equivalent [SE], J0, and J45). To interpret astigmatism using power vector values, the cylinder power (Cp) was determined. RESULTS: This study included 1,395 young adult participants. The average age was 22.17 years (range, 17-39, 84.8% males). The average SE was - 0.65 ± 1.19 diopter (D) compared with - 0.71 ± 0.91D in the auto- and subjective refraction, respectively (p = 0.001). Cp was 0.91 ± 0.52D and 0.67 ± 0.40D, respectively (p < 0.001). This difference was more common in older participants (p < 0.001). J0 and J45 value differences were not significant. The absolute SE value of subjective refraction was lower in the myopic (p < 0.001) and hyperopic (p < 0.001) patients. CONCLUSIONS: Young hyperopic participants tended to prefer "less plus" in subjective refraction compared with autorefraction. Young myopic participants tended to prefer "less minus" in subjective refraction compared with autorefraction. All participants, but mainly older participants, preferred slightly "less Cp" than that measured using autorefraction; The astigmatic axis did not differ significantly between the methods.

Cognitive performance of air personnel following sleep deprivation.

Air forces have developed several methods for reducing fatigue-related accidents. In the Israeli Air Force, the "Dead Tired" workshop was developed with the purpose of presenting aircrew with their objective performance under sleep deprivation conditions. The aim of this study was to examine the cognitive abilities of both aircrew and unmanned aerial vehicle operators, both objectively and subjectively. All Israeli aircrew and unmanned aerial vehicle operators participated in a "Dead Tired" workshop. During the workshop, the participants performed the Psychomotor Vigilance Task, a task that tests their attention abilities, while gathering information on their subjective sleepiness in the form of a Karolinska Sleepiness Scale. Data of 366 participants (25 females), of whom 187 were unmanned aerial vehicle operators and 179 were aircrew, were obtained; and the mean age was 21.8 ± 1.2 years (range 19-26 years). A significant decline in task performance was seen following 20 hr of wakefulness in both unmanned aerial vehicle operators and aircrew (p < 0.001). Unmanned aerial vehicle operators' performance was significantly better throughout the majority of the workshop (p < 0.001). Recovery after the full-night's sleep was seen for unmanned aerial vehicle operators, but not for aircrew (p = 0.008). A high correlation was seen between Psychomotor Vigilance Task performance and Karolinska Sleepiness Scale responses (correlation coefficient = 0.93). Sleep deprivation negatively impacted the performance of both groups of participants. Unmanned aerial vehicle operators were found to be more resilient to the effects of sleep deprivation and were quicker to recover in comparison to aircrew.

Anticholinergic Versus Antihistaminic Treatment for Simulator Sickness Prevention.

Flight simulators have an essential role in aircrew training. Occasionally, symptoms of motion sickness, defined as simulator sickness, develop during these sessions. Preventive methods for motion sickness have been investigated thoroughly; however, only a few studies have examined preventive treatments for simulator sickness. The aim of this study was to examine the efficacy of scopolamine (an anticholinergic drug) compared with cinnarizine (an antihistaminic drug) for helicopter simulator sickness prevention. A validated simulator sickness questionnaire (SSQ) score was used to determine the severity of simulator sickness symptoms in this study. Preliminary SSQ scores and SSQ scores after each sortie were calculated. Each participant was given scopolamine, cinnarizine, or a placebo in a double-blind randomized manner before the first sortie of each training day. Forty-one helicopter pilots participated in the trial. The average age was 30.5 ± 7.1 years. SSQ values significantly improved from an average of 73.30 in the preliminary SSQ questionnaire to an average of 30.92 after 2 hours following the administration of cinnarizine (P = .012, 95%CI 8.071-76.703). Scopolamine was found to be less effective than both cinnarizine and the placebo in the alleviation of simulator sickness symptoms. This study is the first to compare scopolamine with cinnarizine for simulator sickness prevention. Based on the results of this study, we recommend the use of cinnarizine over scopolamine for simulator sickness prevention.

Negative impact of high-performance flights on aviators with mitral valve prolapse.

BACKGROUND: While it appears not to affect healthy aviators' hearts, there are scarce data regarding the impact of high-performance flights on aviators with mitral valve prolapse (MVP). METHODS: A retrospective, comparative cohort study of military aviators with MVP. Subjects were categorized to either high-performance (jet fighter) or low-performance (transport and helicopter) aviators. The primary outcomes were the rates of mitral interventions and of adverse cardiovascular events since being an aircrew candidate and up to the end of flying career. Additional outcomes were echocardiographic measurements and the cumulative proportion of mitral valve interventions over time. RESULTS: Of 33 male aviators with MVP, 18 were high-performance aviators. On average, follow-up started at age 18.5 years and lasted 27.8 ±â€¯10.1 years. Baseline characteristics were similar between the study groups. Aviators of high-performance aircraft had increased rates of mitral valve surgery (33 % vs. 0, p = 0.021), MVP-related complications (39 % vs. 6.7 %, p = 0.046), and a higher incidence of mitral valve repair over time (p = 0.02). High-performance flight was associated with increased intraventricular septum thickness (IVS, 9.7 mm vs 8.9 mm, p = 0.015) and IVS index (p = 0.026) at the last echocardiographic assessment. High-performance aviators tended to develop worsening severity of mitral regurgitation. CONCLUSIONS: High-performance flight may be associated with an increased risk for valvular deterioration and need for mitral surgery in aviators with MVP.

Mitigating Risks of Altitude Chamber Training.

INTRODUCTION: Altitude chambers are used for training aircrews in a hypobaric hypoxic environment to better prepare them for pressurization and oxygen malfunction incidents during flights. However, adverse effects may occur during training sessions, with decompression sickness (DCS) being a major concern. The aim of this study was to examine the risks of different adverse effects during altitude chamber trainings (ACT) in the Israeli Air Force (IAF) facility and to compare them to other training facilities.METHODS: We retrospectively reviewed the records of 1627 individuals in the IAF who were trained in the altitude chamber between 2015 and 2019. Data regarding adverse effects and training safety were extracted. Literature review of altitude chamber trainings was performed and adverse effects rates were compared.RESULTS: There were a total of 91 adverse effects cases in the IAF during the study period. The overall risk rate for an adverse effect was 5.59%. The most common adverse effect was middle ear and sinus barotrauma (69.3% of adverse effects cases), followed by breathing problems (14.3%) and DCS cases (9.9%).CONCLUSIONS: Mitigating the risk for DCS should be major concern during ACT. We recommend setting a standard protocol for an ACT which includes a 45-min preoxygenation period, a maximal ascent rate of 3000 ft · min-1 (914 m · min-1), and setting a maximum altitude of 25,000 ft (7620 m) for fixed-wing trainees.Nakdimon I, Ben-Ari O. Mitigating risks of altitude chamber training. Aerosp Med Hum Perform. 2022; 93(11):811-815.

Return to Flying Duties Following a COVID-19 Booster Dose.

INTRODUCTION: Israel began vaccinating with the booster dose of the Pfizer-BioNTech vaccine in July 2021, before the Food and Drug Administration (FDA) authorized the vaccine in September 2021. The first and second vaccines were shown to have several side effects that could possibly affect aircrews' fitness to fly. Thus, the Israel Air Force (IAF) decided on a disqualification period of 24 h following the first vaccine, and 48 h following the second vaccine. The aim of this study was to determine the disqualification period following the booster dose of the vaccine.METHODS: A survey was conducted among IAF aviators in the Aeromedical Center (AMC) in order to characterize the side effects and their duration following a Pfizer-BioNTech COVID-19 vaccine booster dose.RESULTS: The most common local side effect was injection site pain. The most common systemic side effects were general weakness, fatigue, and myalgia. Duration of side effects was up to 48 h from vaccine administration among the majority of aircrew members.CONCLUSION: The IAF AMC policy for the Pfizer-BioNTech COVID-19 vaccine booster dose recipients is to disqualify from flight for 48 h following the vaccination.Ekshtein A, Hay G, Shapira S, Ben-Ari O. Return to flying duties following a COVID-19 booster dose. Aerosp Med Hum Perform. 2022; 93(7):593-596.

The influence of refractive state and heterophorias on visual acuity and stereoacuity in healthy young adults.

PURPOSE: To evaluate associations of refractive error and heterophoria with best-corrected visual acuity and stereoacuity in a population of healthy young adults. METHODS: Data extracted from the Israeli Defense Forces Air Force candidates database was analyzed retrospectively. Myopia and hyperopia were defined as spherical equivalent of ≤ -0.50 D and ≥ +0.50 D. Cylinder of ≥0.75 D was considered astigmatism. Oblique astigmatism was defined as axis between 30°-60° and 120°-150°. Heterophoria of ≥8Δ for near was considered exo- or esophoria. RESULTS: The study population included 5,491 subjects (75.8% male), with a mean age of 17.6 ± 0.9 years: 2,355 (42.9%) had myopia, 640 (11.6%) had hyperopia, and the rest were emmetropic. Astigmatism was present in 2,006 participants (36.5%), and of those, 619 (30.9%) had oblique astigmatism. Emmetropia was correlated with better best-corrected visual acuity; astigmatism and high hyperopia, with poorer best-corrected visual acuity. A total of 331 subjects (6%) had heterophoria of ≥8Δ; of those, 300 (90.6%) had exophoria and 31 (9.4%) had esophoria. The prevalence of exophoria was higher in the myopic group, and exophoria was not associated with stereoacuity. Esophoria and anisometropia were associated with worse stereoacuity. The best stereopsis was achieved by emmetropic subjects with no astigmatism. CONCLUSIONS: Emmetropia is associated with better best-corrected visual acuity and stereoacuity. Astigmatism and high hyperopia are correlated with poorer best-corrected visual acuity. Exophoria does not interfere with stereopsis, but both esophoria and anisometropia do.

COVID-19 Vaccine and Fitness to Fly.

INTRODUCTION: On December 2020 the U.S. Food and Drug Administration (FDA) authorized the emergency use of Pfizer-BioNTech COVID-19 vaccine. This new vaccine has several side effects that can potentially impair function, which warrants special attention regarding aircrews fitness to fly following vaccination.METHODS: A survey was conducted in the Israeli Air Force (IAF) Aeromedical Center in order to characterize the side effects and their duration following Pfizer-BioNTech COVID-19 vaccine administration to aviators.RESULTS: The most common side effect was injection site pain. Headache, chills, myalgia, fatigue, and weakness were more common following the second dose administration. The difference is statistically significant. Following the second vaccine, duration of side effects was longer compared to the first vaccine (P-value 0.002).CONCLUSION: The IAF Aeromedical center policy for Pfizer-BioNTech COVID-19 vaccine recipients among aircrew members, based on side effects duration and severity, is to temporarily ground from flight duties for 24 and 48 h following the first and the second dose, respectively.Gabbai D, Ekshtein A, Tehori O, Ben-Ari O, Shapira S. COVID-19 vaccine and fitness to fly. Aerosp Med Hum Perform. 2021; 92(9):698701.

Military Aviators with Inflammatory Bowel Diseases Continued Flying.

INTRODUCTION: Military aviators are likely to be first diagnosed with inflammatory bowel diseases (IBD) during military service. Current recommendations support continuing flying with restrictions, but risks may be significant. The aim of the study was to document the long-term results of aviators newly diagnosed with IBD. METHODS: A prospective observational study over a 23-yr period included all Israeli Air Force (IAF) aviators with IBD. Primary end point was the qualification and safety to continue operational flying following IBD diagnosis. RESULTS: Subjects were 16 male aviators with an average follow-up of 130 mo. Average age was 27 (2045) and average time from symptoms onset to final diagnosis was 7.3 mo. Eight (50%) patients had Crohns disease (CD), and the other eight had ulcerative colitis (UC). Eight (50%) were high performance platform aviators. Two patients received biologic treatment, two were treated with repeated corticosteroid courses, and four with immunosuppressive therapy. Two patients underwent surgery and four needed different lengths of hospitalizations. Eight (50%) aviators (3 CD, 5 UC) were grounded for a mean of 177 d (5590). Altogether grounding for IBD aviators was 46/2087 mo (2.2%). Most grounding periods were short term and reversible. All aviators continued flying under annual monitoring or as needed and no compromise of their abilities was documented. CONCLUSIONS: All aviators were able to continue flying and no events of sudden incapacitation or severe disabling flares have been seen among patients. Our study findings support the current recommendation to continue flying when IBD is in stable remission. Tehori O, Koslowsky B, Gabbai D, Shapira S, Ben-Ari O. Military aviators with inflammatory bowel diseases continued flying. Aerosp Med Hum Perform. 2021; 92(10):831834.

Nasoseptal Flap for Skull Base Reconstruction in Children.

Objective The endoscopic endonasal approach is being increasingly used for the resection and reconstruction of anterior skull base (ASB) lesions. Vascularized nasoseptal flaps (NSF) have become the workhorse for the reconstruction of ASB defects, resulting in a significant decrease in the incidence of cerebrospinal fluid (CSF) leaks. The objective of this study was to investigate the efficacy and safety of NSF in children. Methods This is a retrospective analysis of the medical records of all patients under the age of 18 years who underwent endoscopic repair of ASB lesions with the use of NSF at our tertiary medical center between 1/2011 and 8/2016. Results Twelve children underwent ASB defect repair for both benign and malignant neoplasms using the endoscopic endonasal NSF technique. Four children had previously undergone ASB surgery. The male-to-female ratio was 1:1, the average age was 12.3 years, the average hospitalization time was 8.3 days, and the maximum follow-up period was 24 months, during which craniofacial growth appeared to be unimpaired. A lumbar drain was used postoperatively in six cases. Crust formation and synechia were observed in two cases. There was one case of a major long-term complication (a CSF leak followed by meningitis). Conclusions Endoscopic endonasal NSF was both an effective and a safe technique for ASB defect reconstruction in 12 children for both benign and malignant neoplasms. It had a high success rate and a low complication rate. No apparent negative influence on craniofacial growth was observed in our series.

The transcervical approach for parapharyngeal space pleomorphic adenomas: indications and technique.

BACKGROUND: Head and Neck Parapharyngeal space tumors are rare. Pleomorphic Adenomas are the most common Parapharyngeal space tumors. The purpose of this study was to define preoperative criteria for enabling full extirpation of parapharyngeal space pleomorphic adenomas via the transcervical approach while minimizing functional and cosmetic morbidity. METHODS: The surgical records and medical charts of 19 females and 10 males with parapharyngeal space pleomorphic adenomas operated between 1993 and 2012 were reviewed. RESULTS: Fifteen patients were operated by a simple transcervical approach, 13 by a transparotid transcervical approach, and one by a transmandibular transcervical approach. Complications included facial nerve paralysis, infection, hemorrhage and first bite syndrome. There were three recurrences, but neither recurrence nor complications were associated with the type of surgical approach. CONCLUSION: A simple transcervical approach is preferred for parapharyngeal space pleomorphic adenomas with narrow attachments to the deep lobe of the parotid gland and for pleomorphic adenomas originating in a minor salivary gland within the parapharyngeal space.

Cranialization of the frontal sinus for secondary mucocele prevention following open surgery for benign frontal lesions.

OBJECTIVE: To compare frontal sinus cranialization to obliteration for future prevention of secondary mucocele formation following open surgery for benign lesions of the frontal sinus. STUDY DESIGN: Retrospective case series. SETTING: Tertiary academic medical center. PATIENTS: Sixty-nine patients operated for benign frontal sinus pathology between 1994 and 2011. INTERVENTIONS: Open excision of benign frontal sinus pathology followed by either frontal obliteration (n = 41, 59%) or frontal cranialization (n = 28, 41%). MAIN OUTCOME MEASURES: The prevalence of post-surgical complications and secondary mucocele formation were compiled. RESULTS: Pathologies included osteoma (n = 34, 49%), mucocele (n = 27, 39%), fibrous dysplasia (n = 6, 9%), and encephalocele (n = 2, 3%). Complications included skin infections (n = 6), postoperative cutaneous fistula (n = 1), telecanthus (n = 4), diplopia (n = 3), nasal deformity (n = 2) and epiphora (n = 1). None of the patients suffered from postoperative CSF leak, meningitis or pneumocephalus. Six patients, all of whom had previously undergone frontal sinus obliteration, required revision surgery due to secondary mucocele formation. Statistical analysis using non-inferiority test reveal that cranialization of the frontal sinus is non-inferior to obliteration for preventing secondary mucocele formation (P<0.0001). CONCLUSION: Cranialization of the frontal sinus appears to be a good option for prevention of secondary mucocele development after open excision of benign frontal sinus lesions.

Smartphone-based hearing test as an aid in the initial evaluation of unilateral sudden sensorineural hearing loss.

Sudden sensorineural hearing loss (SSNHL) can cause significant morbidity. Treatment with steroids can improve outcome. Delay in initiation of treatment reduces the chance to regain hearing. For this reason SSNHL is considered an emergency. Diagnosis is based on history, physical examination and a standard audiogram, the latter requiring specialized equipment and personnel. Standard audiogram may not be available at the time and place of patient presentation. A smartphone or tablet computer-based hearing test may aid in the decision to prescribe steroids in this setting. In this study the uHear™ hearing test application was utilized. The output of this ear-level air conduction hearing test is reported in hearing grades for 6 frequencies ranging from 250 to 6000 Hz. A total of 32 patients with unilateral SSNHL proven by a standard audiogram were tested. The results of standard and iPod hearing tests were compared. Based on the accepted criterion of SSNHL (at least 30 dB loss - or 2 hearing grades - in 3 consecutive frequencies) the test had a sensitivity of 0.76 and specificity of 0.91. Using a less stringent criterion of a loss of 2 hearing grades over at least 2 frequencies the sensitivity was 0.96 and specificity 0.86. The correlation coefficient for the comparison of the average hearing grade across the 6 measured frequencies of the study and standard audiogram was 0.83. uHear more accurately reflected hearing thresholds at mid and high tones. Similarly to previously published data, low frequency thresholds could be artificially elevated. In conclusion, uHear can be useful in the initial evaluation of patients with single-sided SSNHL by providing important information guiding the decision to initiate treatment before a standard audiogram is available.

Incidence of retropharyngeal calcific tendinitis (longus colli tendinitis) in the general population.

OBJECTIVE: To determine the incidence of retropharyngeal calcific tendinitis (longus colli tendinitis) in a general urban adult population. STUDY DESIGN: Observational study in a municipal medical center. SETTING: Single tertiary referral center. METHODS: All symptomatic patients with a differential diagnosis of retropharyngeal calcific tendinitis underwent fiber-optic assessment, laboratory studies, and imaging studies. The main outcome measure was the incidence of retropharyngeal calcific tendinitis. RESULTS: Thirteen patients with symptoms suggestive of retropharyngeal calcific tendinitis were evaluated in our institution between January 2008 and December 2011. Final diagnosis was made by means of a computed tomographic scan: 8 patients had retropharyngeal calcific tendinitis, 1 had retropharyngeal abscess, and the remaining 4 had other deep neck infections. The mean annual crude retropharyngeal calcific tendinitis incidence was 0.50 cases per 100,000 person-years, and the standardized incidence was 1.31 for the age-matched population. CONCLUSIONS: Retropharyngeal calcific tendinitis is not a rare disease and is probably underdiagnosed because symptoms are nonspecific, treating physicians are often unfamiliar with this entity, and it is a self-limiting pathology.