Aeromedical Decision Making for Military Aircrew with Graves' Disease.

BACKGROUND: Graves' Disease (GD) is a common cause of hyperthyroidism. Although definitive treatment with radioactive iodine (RAI) is preferred for military aircrew, there are cultural and individual differences in receptivity toward RAI, and clinical guidelines that recommend antithyroid drugs (ATD) as the first line therapy. We examined a case series of Republic of Singapore Air Force (RSAF) aviators with GD treated with ATD and the impact of their condition on aeromedical disposition.CASE SERIES: All RSAF aircrew diagnosed with GD and treated with ATD over a 15-yr period were retrospectively identified and analyzed to determine the impact on their fitness for flying duties. The mean age of the 13 aircrew was 33 ± 7.1 yr (range, 25-47 yr), with 11 (84.6%) being males. There were 10 (76.9%) who had ATD as the only treatment while 3 (23.1%) were initially treated with ATD but subsequently underwent RAI or surgery. Of the 10 treated with only ATD, 3 (30.0%) were returned to restricted flying, 6 (60.0%) were returned to unrestricted flying, and 1 (10.0%) is still undergoing ATD titration. There were 10 (76.9%) aircrew who were returned to some form of flying duties while on low doses of ATD.DISCUSSION: This case series suggests that ATD is a viable treatment modality in the aeromedical management of military aviators with GD and it is possible to return military aircrew on a stable maintenance dose of ATD to flying duties. A framework is proposed to support the aeromedical decision-making process for military aircrew in the treatment of GD.Loh EH-T, Soh FW, See B, Tan BBC. Aeromedical decision making for military aircrew with Graves' disease. Aerosp Med Hum Perform. 2021; 92(12):980-986.

Corneal Ectasia Risk And Percentage Tissue Altered In Myopic Patients Presenting For Refractive Surgery.

PURPOSE: A percentage tissue altered (PTA) score of ≥40% has been advocated as an independent indicator of post-operative ectasia risk following laser in-situ keratomileusis (LASIK). This study was performed to test the hypothesis that refractive procedures, such as laser-assisted sub-epithelial keratectomy (LASEK) or small incision lenticule extraction (SMILE), may alter the range of PTA, within which refractive corneal surgery can be safely performed. SETTING: Refractive department, tertiary ophthalmic hospital. DESIGN: Retrospective observational study. METHODS: Review of case notes was performed for patients who presented for refractive surgeries, other than LASIK. To determine the risk of corneal ectasia for each patient prior to refractive surgery, we estimated what each patient's PTA would have been if they had undergone LASIK. The Randleman Ectasia Risk Score System (ERSS) was also calculated. RESULTS: 114 eyes (66 patients) were included. 94 eyes underwent SMILE. 20 eyes underwent LASEK. A significant proportion of eyes had PTA ≥40% - SMILE eyes: up to 31.9%, LASEK eyes: up to 60.0% (at presumed LASIK flap of 120 µm). The maximum calculated PTA was up to 47.9% in the SMILE group and up to 51.5% in the LASEK group. Using ERSS, 12.8-16% of SMILE eyes and 15.0-80.0% of LASEK eyes would have been considered to have moderate-to-high ectasia risk. No post-surgical ectasia was observed at 3 years. CONCLUSION: SMILE and LASEK alter the range of PTA, within which corneal refractive surgery may be performed with a lower risk of developing post-operative corneal ectasia; a safe PTA threshold needs to be determined for these procedures before recommendations for clinical practice can be made.

A Review of Eyelid Margin Malpositions: A Unique Spectrum in a South-East Asian Tertiary Hospital.

PURPOSE: Due to the anatomical differences between the Asian and non-Asian eyelid, the authors hypothesize a different spectrum of eyelid margin malposition conditions seen in Singapore as compared with a predominant Caucasian population. The purpose of the study is to describe the spectrum of eyelid margin malpositions that were operated in a South-East Asian Tertiary Hospital. METHODS: Retrospective study involving all patients who required surgery for eyelid margin malpositions over a 2-year period. The etiology and ethnic spread of patients were analyzed for each eyelid margin malposition. RESULTS: A total of 249 eyelids (144 patients) were analyzed. There were 127 Chinese (88.2%), 8 Malays (5.6%), 6 Indians (4.2%), 2 Indonesians (1.4%), and 1 Korean (0.7%). Epiblepharon (53.4%) was the commonest surgery performed, followed by entropion (25.7%) and ectropion (20.9%). Among patients with epiblepharon and entropion, Chinese patients formed the overwhelming majority (>95%). There were no Eurasians or Indians who presented with epiblepharon or entropion. Among patients with ectropion, there was a higher representation of Indian patients (16.7%). CONCLUSIONS: This study shows that the spectrum of eyelid margin malpositions in Singapore is unique and that developmental epiblepharon remains the commonest eyelid margin malposition requiring surgery. In terms of involutional eyelid margin malpositions, entropion is more common than ectropion, especially among the Chinese. The similarity in terms of eyelid involvement and ethnic distribution of both epiblepharon and involutional entropion suggests that there is a common factor in both these conditions, which the authors infer is due to the unique anatomy of the Asian eyelid.