Search Results (7)

Objective: We assess the prevalence of myopia and its associated factors among schoolchildren in Madrid, Spain, where school-based data using cycloplegic refraction are currently scarce. Methods: A cross-sectional study was conducted in 39 randomly selected schools in Madrid, targeting children in the second (6–7 years) and sixth grades (11–12 years). Parents completed questionnaires detailing family ocular history, the child’s lifestyle, and screen time. Socio-economic status was inferred from the Human Development Index of school districts. Children were examined using a two-stage approach: initial screening with visual acuity testing and Plusoptix photorefraction (myopia screening cut-off ≤ 0.00 D spherical equivalent), followed by confirmatory cycloplegic autorefraction (three drops of cyclopentolate 1% administered at 10 min intervals), with myopia defined as spherical equivalent ≤ −0.50 D. Statistical analyses included chi-square tests and logistic regression models to evaluate associated factors. Results: Of 3680 children invited, 2489 (67.6%) were examined. Myopia prevalence was 6.5% in second grade and 18.7% in sixth grade. Family history of myopia was a significant risk factor (OR 2.04; 95% CI: 1.53–2.70; p < 0.001 for both parents). Outdoor activity during weekends was associated with lower myopia prevalence (OR 0.50; 95% CI: 0.37–0.66; p < 0.01 for 2–6 h). Screen time was not a significant factor in multivariate analysis. Conclusions: This large school-based study using cycloplegic refraction provides more accurate prevalence data for Spanish schoolchildren. It confirms family history as a major risk factor and highlights the association of outdoor activities with lower prevalence of myopia. These results underline the need for preventive measures and suggest areas for future interventional research. Full article

We previously developed machine learning (ML) models for predicting cycloplegic spherical equivalent refraction (SER) and myopia using non-cycloplegic data and following a standardized protocol (cycloplegia with 0.5% tropicamide and biometry using NIDEK A-scan), but the models’ performance may not be generalizable to other settings. This study evaluated the performance of ML models in an independent cohort using a different cycloplegic agent and biometer. Chinese students (N = 614) aged 8–13 years underwent autorefraction before and after cycloplegia with 0.5% tropicamide (n = 505) or 1% cyclopentolate (n = 109). Biometric measures were obtained using an IOLMaster 700 (n = 207) or Optical Biometer SW-9000 (n = 407). ML models were evaluated using R², mean absolute error (MAE), sensitivity, specificity, and area under the ROC curve (AUC). The XGBoost model predicted cycloplegic SER very well (R² = 0.95, MAE (SD) = 0.32 (0.30) D). Both ML models predicted myopia well (random forest: AUC 0.99, sensitivity 93.7%, specificity 96.4%; XGBoost: sensitivity 90.1%, specificity 96.8%) and accurately predicted the myopia rate (observed 62.9%; random forest: 60.6%; XGBoost: 58.8%) despite heterogeneous cycloplegia and biometry factors. In this independent cohort of students, XGBoost and random forest performed very well for predicting cycloplegic SER and myopia status using non-cycloplegic data. This external validation study demonstrated that ML may provide a useful tool for estimating cycloplegic SER and myopia prevalence with heterogeneous clinical parameters, and study in additional populations is warranted. Full article

Background: Cycloplegic refraction is crucial in pediatric eye assessments. While spherical refraction changes due to cycloplegia are well-documented, astigmatic alterations remain unclear. This study assessed the agreement between spherical and astigmatic refraction pre- and post-cycloplegia. Methods: We enrolled 96 patients (mean age: 12.5 ± 2.4 years), including 35 myopes, 30 emmetropes, and 31 hyperopes. Pre- and post-cycloplegia autorefraction and keratometry (Myopia Master) were conducted using 1% cyclopentolate. Ocular residual astigmatism (ORA) was calculated as the difference between refractive and keratometric astigmatism. Astigmatism was analyzed using Fourier analysis (J0 and J45). Results: Cycloplegia resulted in a more positive spherical equivalent (SE) (+0.80 D), with myopes showing the smallest (+0.38 D) and hyperopes showing the highest variation (+1.47 D) in SE. With-the-rule (WTR) astigmatism predominated in the refractive and keratometric measurements, while ORA was against-the-rule (ATR). Cycloplegia shifted the refractive J0 (+0.06 D) towards more WTR and decreased ORA J0 (+0.05 D). No effect was observed in the J45 component. About 25% of patients exhibited astigmatism changes above 0.25 D, with refractive J0 variation being positively correlated with accommodation relaxation (0.044 D per D of relaxation). Conclusion: Cycloplegia induces clinically significant changes in the spherical component, but minimal variations in astigmatic components, predominantly in hyperopic eyes, likely reflecting alterations in crystalline lens anatomy. Full article

Background: Since accommodation may be a source of error affecting the inter-optometrist repeatability of subjective refraction, this study investigated whether the use of cycloplegia could improve this repeatability. Methods: A randomized cross-sectional study was conducted on 42 young hyperopes (18.2 ± 7.7 years, range 6 to 31 years). Subjective refraction was performed by two different optometrists in two measurement sessions: one day without cycloplegia and, on a different day, with cycloplegia, in random order. The inter-optometrist repeatability of all refractive variables (M, J0, and J45) was analyzed, selecting one eye randomly, in terms of the 95% confidence interval of repeatability (r). Results: No statistically significant differences were found between the optometrists for any refractive variable, both with and without cycloplegia (p ≥ 0.05). Furthermore, no correlation was found between participants’ age and the refractive differences between optometrists under both cycloplegic conditions (p ≥ 0.05). However, the use of cycloplegia improved the inter-optometrist repeatability of M (r = 0.37 D) compared to the non-cycloplegic measurements (r = 0.62 D). Conclusions: These results suggest that accommodation in young hyperopes is likely a primary source of error that could explain the discrepancies in subjective refraction between optometrists. Full article

This study aimed to evaluate the clinical information revealed after cycloplegia and assess how age and non-cycloplegic refractive status influence the classification of types of refractive error, as well as the relationship between age and cycloplegia-induced changes in the power of refractive errors. We analysed the records of 472 non-population-based ophthalmology practice patients aged 3–28 years (mean ± SD: 9.1 ± 4.6). Cycloplegia was induced with one drop of cyclopentolate 1% in each eye, and eye refraction was measured 30 ± 5 min later using an objective autorefractometer. Cycloplegia induced a clinically significant (≥0.50 D) hyperopic shift in the spherical equivalent of 60.2% of participants and a myopic shift in 1%, resulting in a 34.1% increase in the frequency of participants with hyperopia, while the frequency of those with myopia and emmetropia decreased by 5.5% and 23.3%, respectively. The average spherical equivalent difference (mean ± SD) induced by cycloplegia was 0.72 ± 0.73 D, with the highest difference observed in the 3–5 years age group (1.18 ± 0.85 D). The differences in astigmatism power (p = 0.84) and astigmatism axis (p = 0.97) between non-cycloplegic and cycloplegic conditions were not statistically significant. Full article

Corneal confocal microscopy (CCM) is emerging as a tool for identifying small fiber neuropathy in both peripheral neuropathies and neurodegenerative disease of the central nervous system (CNS). The value of corneal nerves as biomarkers for efficacy of clinical interventions against small fiber neuropathy and neurodegenerative disease is less clear but may be supported by preclinical studies of investigational agents. We, therefore, used diverse investigational agents to assess concordance of efficacy against corneal nerve loss and peripheral neuropathy in a mouse model of diabetes. Ocular delivery of the peptides ciliary neurotrophic factor (CNTF) or the glucagon-like peptide (GLP) analog exendin-4, both of which prevent diabetic neuropathy when given systemically, restored corneal nerve density within 2 weeks. Similarly, ocular delivery of the muscarinic receptor antagonist cyclopentolate protected corneal nerve density while concurrently reversing indices of systemic peripheral neuropathy. Conversely, systemic delivery of the muscarinic antagonist glycopyrrolate, but not gallamine, prevented multiple indices of systemic peripheral neuropathy and concurrently protected against corneal nerve loss. These data highlight the potential for use of corneal nerve quantification by confocal microscopy as a bridging assay between in vitro and whole animal assays in drug development programs for neuroprotectants and support its use as a biomarker of efficacy against peripheral neuropathy. Full article

The main aim of this study was to compare refraction measurements with and without cycloplegia from two refractors devices, (TRK-2P autorefractometer (TRK-2P) and wavefront-based refraction Visionix 130 (VX130)) in children and adolescents. This descriptive observational study included 20 myopic eyes and 40 hyperopic eyes measured in two different Spanish hospitals. Cycloplegia was carried out by three drops of cyclopentolate hydrochloride 1% (Colircusí cycloplegic, Alcon Healthcare S.A., Barcelona). The mean age of the myopia group was 12.40 ± 3.48 years; for the hyperopia group, the mean age was 7.37 ± 2.47 years. In the myopia group, autorefraction and wavefront-based refraction did not show clinically significant differences in any components between with and without cycloplegia. The hyperopia group showed statistical and clinically significant differences in sphere and SE components between relaxed and non-relaxed states of accommodation, although the cylindrical components were not clinically different. In this study, we considered a value of ≥0.50D as a clinically significant difference in refraction. Therefore, both devices were capable of obtaining accurate refractions without cyclopegia in myopia children, although they did not avoid instrument myopia and accommodation involved in hyperopia children. Moreover, both refractometers could be useful for astigmatism monitoring in children without the need for cycloplegic drops. Full article