Which are the colors of the dress? Review of an atypical optic illusion. / ¿De qué colores es el vestido? Revisión de una ilusión óptica atípica.

OBJECTIVE: In 2015 the picture of a dress went viral on social media. A significant proportion of the population saw it as golden and white (G&W), while another significant proportion saw it as blue and black (B&B). The aim of this article is to review the related literature. MATERIAL AND METHODS: Bibliographic search conducted in Pubmed and Google. The algorithm used was: (color OR colour) AND (dress OR #thedress). The search was limited to the years 2015-2017. No language restrictions were used. The references of the located articles were used to widen the search. RESULTS: The search algorithm retrieved 23 articles related to the topic. Most of the works have been published in journals in the field of perception. Most works address the topic from the point of view of chromatic constancy. Genetic factors seem to have a low weight in the way the dress is perceived. There are few studies on the potential influence of ocular factors. CONCLUSION: This illusion has gained little attention in ophthalmology journals. Although colour constancy is certainly involved, there is still no theory available to explain the dichotomous character of this optical illusion.

Nonsurgical Procedures for Keratoconus Management.

OBJECTIVES: To describe the past 20 years' correction modalities for keratoconus and their visual outcomes and possible complications. METHODS: A review of the published literature related to the visual outcomes and possible complications in the context of keratoconus management using nonsurgical procedures for the last 20 years (glasses and contact lenses) was performed. Original articles that reported the outcome of any correction modalities of keratoconus management were reviewed. RESULTS: The most nonsurgical procedure used on keratoconus management is the contact lens fitting. Soft contact lenses and soft toric contact lenses, rigid gas-permeable contact lenses, piggyback contact lens system, hybrid contact lenses, and scleral and corneoscleral contact lenses form the contemporary range of available lens types for keratoconus management with contact lenses. All of them try to restore the vision, improve the quality of life, and delay surgical procedures in patients with this disease. Complications are derived from the intolerance of using contact lens, and the use of each depends on keratoconus severity. CONCLUSIONS: In the context of nonsurgical procedures, the use of contact lenses for the management of keratoconic patients represents a good alternative to restore vision and improve the quality of live in this population.

[Posterior capsule opacification, capsular bag distension syndrome, and anterior capsular phimosis: A retrospective cohort study]. / Opacificación de la cápsula posterior, síndrome de distensión capsular y síndrome de fimosis de la cápsula anterior: estudio de cohortes retrospectivo.

OBJECTIVE: To determine the incidence and the risk factors involved in the development of the three main postoperative capsular complications: posterior capsule opacification (PCO), capsular bag distension syndrome (CBDS), and anterior capsular phimosis syndrome (ACP). SUBJECTS, MATERIAL AND METHODS: A retrospective cohort study was conducted on 801 patients submitted to cataract surgery in the ophthalmology unit of Hospital del Henares (Madrid) from March 2, 2009 to February 28, 2010. Computerized clinical charts were reviewed during July 2012. PCO was studied using the Kaplan-Meier method (log rank test). RESULTS: A total of 167 patients developed PCO. No association could be demonstrated between PCO and age, sex, diabetes mellitus, phaco technique, IOL model, tamsulosin intake, glaucoma, and age-related macular degeneration. Three patients developed CBDS, all of them have received and Akreos Adapt AO(®) (Bausch & Lomb). Two of them were young men who had received surgery for posterior subcapsular cataracts. Three patients developed ACP, 2 of whom had received a MicroSlim(®) IOL (PhysIOL). CONCLUSIONS: No association was found between PCO and any of the studied variables. Male gender, young age, subcapsular cataract and large non-angulated lens such as Akreos Adapt AO(®) could be associated with CBDS. ACP could be more frequent when microincision IOLs (like MicroSlim(®)) are implanted.

Pupil shape in the animal kingdom: from the pseudopupil to the vertical pupil.

OBJECTIVE: To study the different pupil shapes adopted by the different animal species. MATERIAL AND METHODS: Review of the related literature, using PubMed database. The initial search strategy was pupil shape (limited to animals). The first volume of System of Ophthalmology (Duke-Elder) and Evolution's witness (I. Schwab) were also reviewed. RESULTS: An optic illusion called pseudopupil is usually observed in the compound eyes of insects. The pupil is circular in most vertebrates, however slit vertical pupils are present in cats and in some snake species. Vertical pupils could have a photoprotective function, as it makes a more complete closure possible in photopic conditions, and helps to camouflage the predator. It has also been hypothesized that it could help to correct chromatic aberration. Ruminants are usually endowed with horizontal pupils. This shape could improve the capacity of the eye to detect vertical silhouettes. Some marine animals have crescent-shaped pupils. In these animals, a superior operculum helps to protect the inferior retina from the great amount of light coming from above. CONCLUSION: There is a surprising variability in pupil shape. Through this variability, nature has fitted the eye to different circumstances. The theories proposed to explain this high variability are discussed in detail in the article.

[Everyday anisocoria: anisocoria epidemiology in a secondary care setting]. / Anisocoria cotidiana: epidemiología de la anisocoria en un centro de nivel secundario.

OBJECTIVE: [corrected] To determine the relative importance of the different forms of anisocoria in a General Hospital. METHODS: A prospective, longitudinal study was conducted including all patients referred for this reason to the Neuro-Ophthalmology Unit of the Henares University Hospital, Madrid (Spain), from November 2008 to October 2011. The differences in pupil diameter were studied under high and low luminosity. The patients were given a full ophthalmological examination, as well as performing the apraclonidine, cocaine, pilocarpine 0.125% and pilocarpine 2% tests, if they were considered necessary. RESULTS: Thirty-two cases of anisocoria were referred during the three years of the study. No relationship was found with age or gender. The diagnostic results were: Adie's pupil, 4 cases; Horner syndrome, 5 cases; benign episodic unilateral mydriasis, 3 cases; local causes, 4 cases; physiological anisocoria, 5 cases. Despite a full clinical history and examination, the cause of the anisocoria could not be determined in 11 cases. In 4 of these cases, the patient suffered from migraines and in another 4 psychotropic drugs were taken. Both risk factors were present in 3 cases. In one case the anisocoria was the initial clue that led to the diagnosis of a cervical paraganglioma. CONCLUSIONS: Anisocoria is a clinical sign that does not usually signify a serious disease. With our protocols, a high number of anisocoria cases are still of unknown origin. Migraines and psychotropic drugs could be linked to these forms of anisocoria.