Research Appraisals
Evidence-based critical appraisals of the latest medical research, systematically evaluated using Oxford CEBM methodology.
Showing 5 appraisals
BMC ophthalmology
The effect of lithium on the structure and function of the human retina: a systematic review
BACKGROUND: Bipolar disorder and depression are associated with structural and functional changes in the retina, including a thinner retinal nerve fibre layer (RNFL). Lithium is widely considered the most effective treatment for bipolar disorder, but its mechanism of action is not fully understood. We assessed research looking at the effect of lithium on structural or functional retinal outcomes in humans. METHODS: Searches using the terms 'Lithium' AND 'retina' were carried out to identify peer reviewed studies assessing the impact of lithium on retinal structure or function. These included those with or without a control group comparison, pre- and post- lithium comparisons and observational studies. There were no exclusions based on the quantity or preparation of lithium administered, or the length of administration. Risk of bias was assessed using the Joanna Briggs Institute (JBI) critical appraisal tool for Analytical Cross Sectional Studies, and a narrative synthesis and tabulated summary of the included studies was completed. RESULTS: Seven studies assessing structural outcomes and 10 reporting functional ones were identified, all highly heterogenous and with multiple limitations. Structural outcomes were derived exclusively from optical coherence tomography (OCT) with retinal nerve fibre layer (RNFL) being the most common measurement. There was no evidence of differences in the RNFL between participants with bipolar disorder taking lithium and healthy controls in two larger studies. In six studies looking at differences in those with bipolar disorder taking lithium and those taking valproate, two showed no signs of difference and four showed evidence of thicker RNFL in the lithium group. Studies reporting functional outcomes reported a statistically significant effect of lithium on at least one functional measure, derived from electrooculography, electroretinography, and dark adaptation thresholds. CONCLUSIONS: Current evidence suggests that lithium is likely to have an effect on the retina but limitations in all studies mean better designed and adequately powered prospective studies are required. REGISTRATION: PROSPERO database (Number-CRD42024516635).
31 July 2026
Read appraisal →Neurosurgical review
Safety profile and surgical outcomes of the endoscopic transorbital approach as a skull base surgical corridor: a systematic review and meta-analysis
Endoscopic techniques have enabled minimally invasive approaches in neurosurgery, providing shorter recovery times and favorable outcomes. Among these, the endoscopic transorbital approach (ETOA) has emerged as a versatile surgical modality. Despite the growing body of evidence, complication rates associated with ETOA have not yet been systematically evaluated. We systematically searched PubMed, Embase, Scopus, and Web of Science up to March 2026. We included studies enrolling ≥ 5 patients who underwent ETOA as the sole surgical modality to treat both skull base and orbital lesions, providing data on early or long-term complications. A single-group meta-analysis was performed using a random-effects model with 95% confidence intervals. Heterogeneity was assessed with the I² statistic and further explored through Baujat plots and sensitivity analyses. A total of 11 observational studies, comprising 269 patients, were included. Overall, 21 different pathologies were reported. Meningioma represented the most frequent lesion (60.6% of cases), followed by schwannoma (12.0%), cavernous hemangioma (4.6%), and glioma (2.7%). Mean follow-up was 27.6 ± 15.1 months. CSF leak was observed in 1% (95% CI: 0.00 to 0.04, I² = 46.5%), and wound infection was observed in 3% (95% CI: 0.01 to 0.07, I²=0%). Ptosis occurred in 4% (95% CI: 0.00 to 0.14, I²=79.4%) and diplopia occurred in 6% (95% CI: 0.01 to 0.14, I²=68.9%). Medial gaze palsy occurred in 9% (95% CI: 0.04 to 0.18, I²=8.8%). Improvement in visual function was seen in 47% (95% CI: 0.22 to 0.73, I²=88.7%). Visual dysfunction occurred in 1% (95% CI: 0.00 to 0.04, I²=48.6%). Transient facial numbness occurred in 16% (95% CI: 0.09 to 0.25, I²=35.0%). Mortality was 0% (95% CI: 0.00 to 0.02, I²=28.7%). ETOA is a safe and promising technique for managing a wide range of skull base and orbital lesions. Future prospective and comparative studies are needed to refine indications and validate its long-term efficacy.
14 May 2026
Read appraisal →Neurology
Idiopathic Intracranial Hypertension Prevalence and Hormonal Contraception: A Meta-Analysis
BACKGROUND AND OBJECTIVES: Women's health advice in people living with idiopathic intracranial hypertension (IIH) is inconsistent, primarily due to an enduring concern that hormonal contraception (HC), including oral contraceptive pills (OCPs) and hormonal intrauterine devices (IUDs), might be associated with a higher prevalence of IIH. This systematic review and meta-analysis examines whether a meaningful association exists between HC use and IIH prevalence. METHODS: Systematic searches of Ovid MEDLINE, Embase, and the Cochrane Library were conducted from their inception to May 14, 2025. Gray literature and citation lists were also reviewed. Observational studies comparing HC use among women with IIH to controls without IIH were included. Noncomparative studies and pharmacovigilance analyses were excluded. Two independent reviewers conducted data extraction, assessed the quality of studies using the Newcastle-Ottawa Scale, and appraised the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation framework. A random-effects meta-analysis using the Mantel-Haenszel method in Review Manager 5.4 was conducted to evaluate the association between HC use and IIH prevalence, the primary outcome of interest, with leave-one-out sensitivity analyses and subgroup analyses stratified by HC modality. RESULTS: A total of 13 studies (nIIH = 5,351 and ncontrol = 669,260; mean age = 33.3 years; 100% female) were included. HC use was not significantly associated with IIH prevalence (odds ratio [OR] 0.93, 95% CI 0.69-1.24, p = 0.60, I2 = 82%; n = 12 studies). Subgroup analyses revealed no significant associations for OCPs (OR 0.91, 95% CI 0.72-1.16, p = 0.45, I2 = 25%; n = 6 studies), IUDs (OR 1.45, 95% CI 0.61-3.44, p = 0.39, I2 = 92%; n = 5 studies), or medroxyprogesterone acetate injections (OR 1.21, 95% CI 0.84-1.74, p = 0.30, I2 = 2%; n = 2 studies). Findings were largely robust in sensitivity analyses. Quality assessments ranged from poor to good, with the certainty of evidence rated as very low to low. DISCUSSION: The meta-analysis found no significant association between HC use and IIH prevalence, with consistent results across various HC modalities. This evidence provides confidence to reassure patients with IIH and clinicians that the directed use of HC should be continued as appropriate. The limited quality of available evidence and considerable heterogeneity highlights the necessity for large-scale, well-designed studies, particularly in diverse patient populations, to validate these findings.
3 May 2026
Read appraisal →Translational vision science & technology
OptiDON-Guard: An Ensemble Model for Identification of Dysthyroid Optic Neuropathy Using Optical Coherence Tomography Angiography
PURPOSE: To explore the value of machine learning models based on optical coherence tomography angiography (OCTA) in identifying dysthyroid optic neuropathy (DON). METHODS: A retrospective, dual-center, cross-sectional study was conducted involving 346 thyroid eye disease patients (with/without DON) from two institutions. Participants underwent ophthalmic examinations, including OCTA scans centered on the macula and optic nerve head. The OCTA data from Center 1 were split into a training set and an internal validation set, while the data from Center 2 served as an external test set. Features were extracted from OCTA images, and a wrapper-based feature selection strategy identified the optimal subset. A two-tiered stacking modeling framework was used, incorporating baseline model construction, data augmentation using pseudo-labeling, and ensemble integration. Model performance (area under the curve [AUC], accuracy, sensitivity, specificity, precision) was evaluated alongside receiver operating characteristic, calibration, and decision curve analyses. Additionally, the SHapley Additive exPlanation method was used to interpret feature contributions. RESULTS: The ensemble model, OptiDON-Guard, demonstrated superior performance to individual models on both internal validation and external test sets. In the internal validation set, it achieved an AUC of 0.872, accuracy of 0.943, sensitivity of 0.667, specificity of 0.979, and precision of 0.943. In the external test set, it maintained strong performance with an AUC of 0.854, accuracy of 0.816, sensitivity of 0.767, specificity of 0.842, and precision of 0.854. CONCLUSIONS: The OptiDON-Guard is a reliable, interpretable, and clinically applicable tool for identifying DON. TRANSLATIONAL RELEVANCE: The OptiDON-Guard offers a valuable clinical tool to enhance the diagnostic precision of DON.
9 Apr 2026
Read appraisal →Translational vision science & technology
Diagnosis of High Intracranial Pressure by Non-Optic Nerve Retinal Image Features
PURPOSE: To assess the performance of an artificial intelligence deep learning (DL) model compared with neuro-ophthalmologists for the classification of subjects with elevated intracranial pressure (ICP) and papilledema versus control subjects, based on retinal images with and without masking the optic nerve heads (ONHs). METHODS: Widefield retinal images were obtained in 32 subjects (70 images) with elevated ICP and papilledema and 31 control subjects (62 images). ONH-unmasked images were generated by cropping the image to a 30° circular region. ONH-masked images were generated by masking the ONH and peripapillary region. Classification was performed using a convolutional neural network model and by two neuro-ophthalmologists (graders). RESULTS: For the ONH-unmasked images, the classification accuracies of the model, grader 1, and grader 2 were 83% (area under the receiver operating characteristic curve [AUC] = 0.94), 93%, and 86%, respectively. For the ONH-masked images, the classification accuracies of the model, grader 1, and grader 2 were 79% (AUC = 0.90), 66%, and 76%, respectively. The classification performance of the DL model and graders did not significantly differ for both datasets (P ≥ 0.38). There was no significant effect of ONH masking on the performance of the DL model (P = 1.0) and grader 2 (P = 0.38), whereas the performance of grader 1 was significantly reduced (P = 0.02). CONCLUSIONS: Both expert graders and the DL models demonstrated excellent performance for classifying retinal images of subjects with elevated and normal ICP using images with or without masking the ONH. TRANSLATIONAL RELEVANCE: Methods for assessment of non-optic nerve retinal image features have the potential to improve diagnosis and monitoring the progression and response to treatment of elevated ICP.
7 Apr 2026
Read appraisal →