using-an-automated-hirschberg-test-app-to-evaluate-ocular-alignment

Using an Automated Hirschberg Test App to Evaluate Ocular Alignment

A smartphone app has been developed to perform the automated photographic Hirschberg test for objective measurement of ocular misalignment. By computing ...

Harvard Medical School

Tuberin, the Tsc2 gene product, integrates the phosphatidylinositol 3-kinase/mitogen-activated protein kinase (mitogenic) and LKB1/AMP-activated protein kinase (AMPK; energy) signaling pathways, and previous independent studies have shown that loss of tuberin is associated with elevated AMPK signaling and altered p27 function. In Tsc2-null tumors and tumor-derived cells from Eker rats, we observed elevated AMPK signaling and concordant cytoplasmic mislocalization of p27. Cytoplasmic localization of p27 in Tsc2-null cells was reversible pharmacologically using inhibitors of the LKB1/AMPK pathway, and localization of p27 to the cytoplasm could be induced directly by activating AMPK physiologically (glucose deprivation) or genetically (constitutively active AMPK) in Tsc2-proficient cells. Furthermore, AMPK phosphorylated p27 in vitro on at least three sites including T170 near the nuclear localization signal, and T170 was shown to determine p27 localization in response to AMPK signaling. p27 functions in the nucleus to suppress cyclin-dependent kinase-2 (Cdk2) activity and has been reported to mediate an antiapoptotic function when localized to the cytoplasm. We found that cells with elevated AMPK signaling and cytoplasmic p27 localization exhibited elevated Cdk2 activity, which could be suppressed by inhibiting AMPK signaling. In addition, cells with elevated AMPK signaling and cytoplasmic p27 localization were resistant to apoptosis, which could be overcome by inhibition of AMPK signaling and relocalization of p27 to the nucleus. These data show that AMPK signaling determines the subcellular localization of p27, and identifies loss of integration of pathways controlling energy balance, the cell cycle, and apoptosis due to aberrant AMPK and p27 function as a feature of cells that have lost the Tsc2 tumor suppressor gene.

AMP-activated protein kinase signaling results in cytoplasmic sequestration of p27.

Chapter 7- Restoring Vision to the Blind: Advancements in Vision Aids for the Visually Impaired.

To test a prototype magnet system (magnetic levator prosthesis) for the ability to comfortably and non-invasively provide eye opening with maintenance of the blink in people with paralytic ptosis and determine preliminary efficacy for short-term clinical application.

A Prototype External Magnetic Eyelid Device for Blepharoptosis.

Although the impact of homonymous visual field defects (HFDs) on mobility has been investigated previously, the emphasis has been on obstacle detection. Relatively little is known about HFD patients' ability to judge collisions once an obstacle is detected. We investigated this using a walking simulator.

Asymmetry in the Collision Judgments of People With Homonymous Field Defects and Left Hemispatial Neglect.

Peripheral prisms (p-prisms) shift peripheral portions of the visual field of one eye, providing visual field expansion for patients with hemianopia. However, patients rarely show adaption to the shift, incorrectly localizing objects viewed within the p-prisms. A pilot evaluation of a novel computerized perceptual-motor training program aiming to promote p-prism adaption was conducted.

A Pilot Study of Perceptual-Motor Training for Peripheral Prisms.

Visual impairments are common after traumatic brain injury (TBI) and negatively affect quality of life. We describe a 39-year-old woman with a severe TBI who was evaluated by the inpatient optometry and vision rehabilitation service with findings of complete right homonymous hemianopia and right cranial nerve III palsy with 30-degree right exotropia (eye turn out) and complete right ptosis (eyelid will not open). The 30-degree exotropia advantageously generated 30 degrees of right visual field expansion when the right ptosis was treated with a magnetic levator prosthesis, which restores eyelid opening. Once opened, the patient used visual field expansion derived from a right exotropia to overcome functional impairments caused by right hemianopia. Field expansion improved the patient's wheelchair mobility and reaching tasks during inpatient therapy. This is the first report of visual field expansion by strabismus facilitated by correction of ptosis. Strabismus should be considered for its potential field expansion benefits when homonymous visual deficits are present, before considering patching. A multidisciplinary vision rehabilitation team is well suited to make this determination.

Restoration of Vision After Brain Injury Using Magnet Glasses.

Patching for double vision is a common palliative treatment for head-trauma patients with acquired strabismus when prisms are not feasible.

Patching for Diplopia Contraindicated in Patients with Brain Injury?

Drivers with homonymous hemianopia (HH) were previously found to have impaired detection of blind-side hazards, yet in many jurisdictions they may obtain a license. We evaluated whether oblique 57Δ peripheral prisms (p-prisms) and perceptual-motor training improved blind-side detection rates.

Driving With Hemianopia VI: Peripheral Prisms and Perceptual-Motor Training Improve Detection in a Driving Simulator.

We further optimized and evaluated the safety of the magnetic levator prosthesis (MLP) for temporary management of severe blepharoptosis, and compared efficacy and comfort against the ptosis crutch.

The Magnetic Levator Prosthesis for Temporary Management of Severe Blepharoptosis: Initial Safety and Efficacy.

The first report on the use of peripheral prisms (p-prisms) for patients with left neglect and homonymous visual field defects (HVFDs).

Peripheral Prisms Improve Obstacle Detection during Simulated Walking for Patients with Left Hemispatial Neglect and Hemianopia.

We evaluate a smartphone application (app) performing an automated photographic Hirschberg test for measurement of eye deviations.

Kevin Houston

Schepens Eye Research Institute,
Mass Eye & Ear,
Schepens Eye Research Institute, Mass Eye & Ear

Harvard Medical School

Using an Automated Hirschberg Test App to Evaluate Ocular Alignment

Kevin Houston

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Harvard Medical School

Using an Automated Hirschberg Test App to Evaluate Ocular Alignment

Schepens Eye Research Institute,
Mass Eye & Ear,
Schepens Eye Research Institute, Mass Eye & Ear