Comparability of the Retinomax K-plus 3 handheld autorefractometer in quick mode versus on-table autorefractometer in standard mode.

INTRODUCTION: This study analyzes the comparability of measurements taken by a Retinomax K-plus 3 handheld autorefractometer in Quick mode and a Topcon KR-800 on-table autorefractometer in standard mode on the pediatric population, and establishes their correlation. METHODS: It is a retrospective comparative study. Spherical diopter power (SPH), cylindrical diopter power (CYL), angle of cylindrical axis (AX), and spherical equivalent (SE) were measured with the Retinomax in Quick mode and with the Topcon in standard mode. Each patient was evaluated in cycloplegic and non-cycloplegic conditions by both autorefractometers. Student's t-test was performed between the two instruments for SPH, CYL, and SE. The Pearson correlation coefficient was calculated and the dispersion was represented using Bland-Altman graphs, also evaluating the subgroup of patients under 4 years of age. A descriptive analysis of the percentages of measures that differed was performed. RESULTS: It included 98 eyes of 49 subjects (age range: 3-16 years). The data for HPS without cycloplegia are virtually identical, whereas with cycloplegia there is a hyperopic bias of +0.5 diopters measured with Retinomax. CYL results are very similar with and without cycloplegia. There is a high Pearson correlation for both instruments (>0.91) and a low degree of dispersion in the Bland-Altman plots under cycloplegia. CONCLUSION: The Retinomax data were consistent with those obtained by Topcon. The Retinomax is a useful instrument for detecting refractive errors in children between 3 and 16 years of age.

Repeatability and comparability of a new swept-source optical coherence tomographer in optical biometry.

PURPOSE: To evaluate the reproducibility in the measurement of ocular biometric parameters using a new swept-source optical coherence tomographer and its comparability with an optical low coherence reflectometry biometer. DESIGN: An observational, descriptive, cross-sectional study. METHODS: 45 right eyes of 45 patients diagnosed with cataract were included. Three successive biometric measurements with Anterion and one with Lenstar LS900 were performed on each patient. The following variables were collected: axial length (AXL), anterior chamber depth (ACD), flat K (K1), steep K (K2), central corneal thickness (CCT), lens thickness (LT) and white-to-white distance (WTW). The intrasubject standard deviation (Sw) and the coefficient of Pearson "R" were calculated in order to assess the repeatability. The intraclass correlation coefficient (ICC) and the concordance correlation coefficient (CCC) were obtained to evaluate the comparability between devices. A Bland-Altman plot was performed for each variable. RESULTS: The coefficient of Pearson was excellent and statistically significant in the evaluation of the repeatability in all the variables. The highest values were 0.987 (AXL), 0.983 (CCT) and 0.942 (ACD). There were no statically significant differences between repeated measurements with Anterion in all the parameters. The ICC and CCC were excellent in the evaluation of AXL, CCT and ACD, and were also good in regard to K1, K2, LT and WTW. CONCLUSIONS: Performing biometry with the SS-OCT Anterion is a reliable and reproducible procedure, and it is comparable with the Lenstar LS900.

Limits of the precision in refractive results after cataract surgery.

BACKGROUND AND OBJECTIVE: In order to improve refractive results in cataract surgery with an intraocular lens implant, it is important to know the sources of error as well as the limit of this process. Therefore, the objective of the present work is to approximate the theoretical limit in the precision in the refractive result after cataract surgery with the currently available means and to assess the impact of different sources of error in this process. MATERIALS AND METHODS: We conducted a search of the literature to determine the variability provided by each component of the process. Based on the Barrett Universal-II formula, we performed an error propagation analysis. The theoretical limit was defined as the situation in which the refractive result is only affected by the variability in the parameters introduced in the formula, the tolerance of the intraocular lens and the subjective refraction. RESULTS: The main contributors to the error were (1) intraoperative and postoperative variability variables not considered by the formulas (49.33%), (2) postoperative subjective refraction (38.29%), (3) mean keratometry (5.98%) and (4) the variability in the labelling of the power of the intraocular lens (5.09%). The theoretical limit obtained for the intraocular lens calculation with the means available today was 91.9% of the eyes between ±0.50D. CONCLUSIONS: We found a theoretical limit for the intraocular lens calculation of 91.9% of the eyes between ±0.50D. Approaching the precision limit described in the study requires the use of optical biometrics and state-of-the-art formulas, a reproducible surgical technique, and the compensation of systematic errors by adjusting constants.

Permanent damage of the inner retinal layers in a patient with migraine: a different case of paracentral acute middle maculopathy.

We report the case of a 20-year-old patient who presented a paracentral scotoma in her left eye that had not disappeared after a migraine attack two days before. Ocular examination showed two pale paracentral areas suggesting an acute ischemia insult. Several causes of retinal ischemia were ruled out and the patient was diagnosed with secondary retinal vasospasm. One year later, the patient suffers an atrophy of the inner layers of the affected retina and has a paracentral chronic scotoma in her left eye. Retinal vasospasms can result in irreversible lesions and chronic symptoms due to ischemia and cell destruction. This unusual case reports a permanent damage due to retinal vasospasm secondary to migraine attack. The finding of typical lesions and the history of migraine could be compatible with the diagnosis of paracentral acute middle maculopathy (PAMM).

Posterior bilateral lens luxation in an agitated patient: Cause or consequence? / Luxación posterior bilateral del cristalino en una paciente agitada, ¿causa o consecuencia?

Complete posterior lens dislocation is an infrequent clinical entity. Trauma is the first cause of secondary lens dislocation. Most of the cases are unilateral, and bilateral cases are unusual. We report the uncommon case of a 70-year-old woman with evidence of a posterior bilateral dislocation of the lens in the context of an acute onset of confusional syndrome. We discuss about sensory deprivation as a trigger for acute confusion and agitation in patients with predisposing conditions. In addition, we describe the benefits that, in our experience, the refloating technique with perfluorocarbon liquid provides for the surgical approach to these cases.

Optical neuropathy due to inhaled cocaine, causality or chance. / Neuropatía óptica secundaria a consumo de cocaína inhalada. Causalidad o casualidad.

A 44-year-old man, active cocaine consumer, who referred decrease in visual acuity in the right eye in 24 hours of evolution, being 0,05 in that eye and 1 in the left eye. The examination showed a relative afferent pupil defect and a swelling head of optic nerve. The systemic studies performed were normal, except the nuclear magnetic resonance of the brain that showed a thickening of the maxillary and frontal sinus mucosa, compatible with sinusitis. Hospital admission and the start of intravenous corticosteroid treatment were decided, with a favourable evolution, a visual acuity of 1.0 in both eyes and an anatomical improvement of the optic nerve head. Due to the medical history of the patient and the assessment of other plausible alternative diagnoses, we established the diagnosis of optical neuropathy due to inhaled cocaine abuse.