1. Rod-Driven Electroretinography
Electroretinography is an advanced eye test used to determine the visual pathway loop from the eye to the brain and back to the eye. This test is important in individuals who experience night blindness, light-sensitivity, glare, and poor vision. It is also used to determine possible underlying neurological problems in individuals with strabismus, vision loss, or frequent changes in their vision.
2. Pupil Diameter Measurement
The average pupil size is 4-5mm and must be generally equal for both eyes. Unequal pupil sizes, constricted (very small) pupils, or dilated (very large) pupils, may mean an underlying neuro-visual dysfunction or a serious neurological problem.
3. Binocular Fusion Test and Amblyopia Screening
This test is useful for individuals who may have amblyopia (lazy eye), diplopia (double vision) and other binocular vision or neuro-visual anomalies. Amblyopia, diplopia, and binocular vision anomalies are very common in children and adults who have unequal eye grades between their two eyes, or have a history of stroke, traumatic brain injury, or other neurological conditions. Amblyopia occurs when the brain suppresses visual input from the eye with poorer vision in order to maintain clear vision in the fellow eye which has better vision. The suppression causes the “weaker eye” to worsen and function less and less than the “stronger” more dominant eye, thus the term “lazy eye”.
4. Strabismus Screening
This test is used to evaluate the direction and severity of eye misalignments in squint or cross-eyed individuals. The test can detect even the smallest amounts of eye misalignments. It is very useful in the early detection and diagnosis of strabismus (squint or cross-eye).
5. Stereo Acuity Measurement
The two eyes send slightly different point of views to the brain. The brain combines and overlaps the two slightly different visual inputs into a single three dimensional image to help accurately judge depth and distance of objects. This neuro-visual ability is called stereopsis and is very useful when one is walking down a flight of stairs and needs to correctly judge the depth of the steps. It is very important when one is driving or parking a car and needs to correctly judge the distance of obstacles in the surroundings.
6. Prism Cover Test
Prism cover test is the gold standard in measuring strabismus. It is used to determine the direction and amount of eye deviation by alternately covering and uncovering the eye while using varying amounts of prisms to straighten and align the eyes. Prisms are special lenses that change the direction of light to help align the eyes.
7. Corneal Light Reflex and Prism Test
Corneal Light Reflex and Prism Test, also known as Hirschberg and Krimsky Test, is a confirmatory and alternative strabismus test. It is used to determine the direction and amount of eye deviation in children, individuals with special needs, or individuals who have a vision of 20/400 or poorer. The test uses the location of the corneal light reflex to determine eye misalignment. Just like the prism cover test, it also uses varying amounts pf prisms to straighten and align the eyes.
8. Functional Oculomotor Test
The functional oculomotor test is used to assess the actions of the extraocular recti and oblique eye muscles, as well as their nerve supply which are the Oculomotor nerve, Abducens nerve, and Trochlear nerve.
9. Saccadic Eye Movement Test
Saccadic eye movements are quick voluntary eye movements made from one target to another. Horizontal saccades are important when reading. Horizontal and vertical saccades are an essential part of the vestibular system. The vestibular system is responsible for maintaining balance and spatial orientation. Problems in the vestibular system can result to vertigo, nausea, and balance issues.