Eyedrop Instillation Techniques, Difficulties, and Currently Available Solutions: A Literature Review.

Purpose: To review current eyedrop instillation techniques, common difficulties faced by patients instilling eyedrops, available eyedrop assistive devices, and patient education regarding eyedrop instillation. Methods: PubMed, Embase, and Google Scholar were searched from conception until June 2022 for articles on eyedrop instillation difficulties, techniques, tools, and patient education. Results: Instillation involves pulling down the lower eyelids and placing drops on the corneal surface or conjunctival fornix, followed by closing of the eyelids for about 1 min. Examples of techniques include eyelid closure and nasolacrimal obstruction techniques. Patients encounter many difficulties when administering eyedrops, including but not limited to poor visibility, squeezing the dropper bottle, aiming the bottle, and accidentally blinking. However, devices are available that assist with aim and dropper compression-force reduction in eyedrop instillation. These can be particularly useful in patient demographics with diminished manual dexterity or the ability to generate force from their fingers. Furthermore, despite patient education in eyedrop instillation not being a common practice, it has been found that adequate patient education can lead to significant improvement in eyedrop instillation technique. Conclusions: While many factors are associated with poor eyedrop instillation technique, there are many solutions available including assistive devices and proper instillation education.

Alternating Hypotropia with Pseudoptosis: A New Phenotype of Congenital Cranial Dysinnervation Disorder.

Congenital cranial dysinnervation disorders, also known as CCDDs, are characterized by aberrant innervation to extraocular and facial muscles resulting in unusual forms of incomitant strabismus. Anomalous innervation to extraocular muscles can result in a wide variety of phenotypes causing various clinical conditions such as Duane syndrome, congenital fibrosis of the extraocular muscles, and Möbius syndrome. We report a case of bilateral dysinnervation disorder causing atypical ocular movements in both eyes as the patient changes fixation from one eye to the other and from right gaze to left gaze that fits with the wider diagnosis of CCDDs.

The Iroquois homeobox gene Irx2 is not essential for normal development of the heart and midbrain-hindbrain boundary in mice.

The Iroquois homeobox (Irx) genes have been implicated in the specification and patterning of several organs in Drosophila and several vertebrate species. Misexpression studies of chick, Xenopus, and zebra fish embryos have demonstrated that Irx genes are involved in the specification of the midbrain-hindbrain boundary. All six murine Irx genes are expressed in the developing heart, suggesting that they might possess distinct functions during heart development, and a role for Irx4 in normal heart development has been recently demonstrated by gene-targeting experiments. Here we describe the generation and phenotypic analysis of an Irx2-deficient mouse strain. By targeted insertion of a lacZ reporter gene into the Irx2 locus, we show that lacZ expression reproduces most of the endogenous Irx2 expression pattern. Despite the dynamic expression of Irx2 in the developing heart, nervous system, and other organs, Irx2-deficient mice are viable, are fertile, and appear to be normal. Although chick Irx2 has been implicated in the development of the midbrain-hindbrain region, we show that Irx2-deficient mice develop a normal midbrain-hindbrain boundary. Furthermore, Irx2-deficient mice have normal cardiac morphology and function. Functional compensation by other Irx genes might account for the absence of a phenotype in Irx2-deficient mice. Further studies of mutant mice of other Irx genes as well as compound mutant mice will be necessary to uncover the functional roles of these evolutionarily conserved transcriptional regulators in development and disease.

Transscleral suture fixation following recurrent toric intraocular lens rotation.

We describe a surgical technique of transscleral suture fixation for recurrent rotation of a double-loop hydrophilic acrylic toric intraocular lens (IOL) in the capsular bag. Two 9-0 polypropylene sutures are placed in the proximal and distal angulations of 1 of the IOL haptics through the capsular bag. The clockwise and counterclockwise traction provided by these sutures prevents rotation of the IOL in either direction. This technique can be used in cases of spontaneous postoperative IOL rotation to achieve stabilization. In the case we describe, the IOL remained stable 11 months following transscleral suture fixation at the desired axis.

Factors affecting postoperative stereopsis in acquired nonaccommodative esotropia.

OBJECTIVE: To identify and examine factors that affect postoperative binocularity in children diagnosed with acquired nonaccommodative esotropia (ANAET). DESIGN: Retrospective chart review. PARTICIPANTS: Thirty-four pediatric patients who received surgery for ANAET by 1 surgeon (I.M.) at the Ivey Eye Institute, University of Western Ontario (London, Ont.). METHODS: A multivariate logistic regression analysis was performed to evaluate the effect of the following factors on achieving stereopsis postoperatively: age at onset of esotropia (AO), duration of misalignment (DOM), presence of A/V pattern, recent intermittency of esotropia, and presence of dense amblyopia. RESULTS: Forty-one percent of all patients achieved stereoacuity of 100 seconds of arc or better. AO was found to be the only factor significantly associated with postoperative stereopsis (adjusted odds ratio = 1.063, P<0.05). None of the children with AO who were younger than 30 months regained bifoveal fixation regardless of their DOM. CONCLUSIONS: Age of onset appears to play a crucial role on postoperative functional outcome in children with ANAET. Delayed surgery in children with an age of onset beyond 30 months did not seem to be detrimental to regaining bifoveal fixation.

The homeodomain transcription factor Irx5 establishes the mouse cardiac ventricular repolarization gradient.

Rhythmic cardiac contractions depend on the organized propagation of depolarizing and repolarizing wavefronts. Repolarization is spatially heterogeneous and depends largely on gradients of potassium currents. Gradient disruption in heart disease may underlie susceptibility to fatal arrhythmias, but it is not known how this gradient is established. We show that, in mice lacking the homeodomain transcription factor Irx5, the cardiac repolarization gradient is abolished due to increased Kv4.2 potassium-channel expression in endocardial myocardium, resulting in a selective increase of the major cardiac repolarization current, I(to,f), and increased susceptibility to arrhythmias. Myocardial Irx5 is expressed in a gradient opposite that of Kv4.2, and Irx5 represses Kv4.2 expression by recruiting mBop, a cardiac transcriptional repressor. Thus, an Irx5 repressor gradient negatively regulates potassium-channel-gene expression in the heart, forming an inverse I(to,f) gradient that ensures coordinated cardiac repolarization while also preventing arrhythmias.