Microtropia Flashcards
(22 cards)
What is anisometropia?
A condition where the two eyes have unequal refractive power.
It can lead to amblyopia if not corrected.
Define foveal fixation.
The process of focusing on an object using the fovea, the central part of the retina.
Parafoveal fixation refers to fixation just outside the fovea.
What is normal correspondence?
A condition where the visual directions of the two eyes correspond correctly.
Abnormal correspondence occurs when the visual directions do not align properly.
Differentiate between microtropia with identity and microtropia without identity.
Microtropia with identity: No manifest deviation; coincident with angle of deviation.
Microtropia without identity: Very small manifest deviation; may have central or eccentric fixation.
Identity indicates a harmonious relationship between fixation and deviation.
What is primary microtropia?
An initial defect of microtropia with no history of larger angle strabismus.
It may accompany other forms of concomitant strabismus.
What is monofixation syndrome?
A condition characterized by the presence of only one eye fixing on an object while the other eye has a small angle deviation.
It is often associated with microtropia.
What is a central suppression scotoma?
A blind spot in the central vision caused by the brain suppressing the input from one eye.
It commonly occurs in strabismus conditions.
Define crowding in the context of amblyopia.
The phenomenon where visual acuity is reduced in the presence of nearby visual stimuli.
It affects the ability to identify letters or objects when they are surrounded by other stimuli.
What does fixation ophthalmoscopy assess?
It evaluates the stability and location of fixation in patients with strabismus.
Visuoscopy is another method to assess fixation.
What is the purpose of the 4 PD prism reflex test?
To assess the presence and magnitude of strabismus by measuring the prism reflex at 4 prism diopters.
It can be performed in both base-out (BO) and base-in (BI) directions.
Explain the prism cover test (PCT).
A test used to determine the presence of strabismus by alternating the cover of each eye and observing eye movements.
Simultaneous PCT assesses the manifest component, while alternate PCT assesses both manifest and latent components.
What is manifest strabismus?
A type of strabismus that is always present and noticeable.
Associated latent strabismus may become apparent under certain conditions.
What is sensory fusion?
The ability of the brain to combine visual input from both eyes into a single image.
It is crucial for depth perception and 3D vision.
What is motor fusion?
The ability to align the eyes to achieve single vision.
It compensates for any misalignment between the eyes.
What is stereoacuity?
The ability to perceive depth and three-dimensional structure based on visual input from both eyes.
It is often reduced in strabismic patients.
Fill in the blank: The _______ aims to obtain the best possible visual acuity (VA) in each eye.
Aims
What is the significance of the size of deviation in strabismus?
It influences the visual acuity and treatment outcomes in patients with strabismus.
Smaller deviations often correlate with better visual acuity and stereoacuity.
What is the management goal for amblyopia treatment?
To achieve equal visual acuity in both eyes.
This may involve refractive correction and other therapies.
True or False: Microtropia is often associated with a larger angle of strabismus.
False
What are the characteristics of microtropia?
- Small angle manifest strabismus (10 PD or less)
- Often associated with latent strabismus
- Subnormal binocular single vision (BSV)
- Reduced stereopsis
- Foveal suppression scotoma
- Parafoveal fixation
- Reduced visual acuity
It may also include anisometropia.
What is the purpose of a differential diagnosis in microtropia?
To distinguish microtropia from other conditions like small angle manifest strabismus.
It helps in determining appropriate treatment.
What factors are considered in the investigation of microtropia?
- Case history
- Refraction
- Visual acuity
- Fundus examination
- Cover test
- Binocular single vision assessment
- Fixation assessment
These factors help in understanding the severity and impact of microtropia.
