Obligatory medical device diagnostics.
- Vision test with visual acuity (visual sharpness) in the distance with glasses present and current refraction (“spectacle lens determination”) on refractometer (subjective refraction determination)If good visual acuity is not achieved, then
- Attachment of a stenopeic diaphragm during vision testing (aid for differential diagnostic assessment of reduced visual acuity; usually consists of a round, opaque plastic disc about three centimeters in diameter with a small hole in the center; used to assess a refractive error of the eye, i.e., a refraction-based defect of vision (e.g. Myopia (nearsightedness) or astigmatism (astigmatism)): if visual acuity improves with the best correction with a stenopeic gap, this demonstrates better retinal function; thus, at least part of the visual loss is due to optical disturbances in front of the retina (retinal), (→ testing for the presence of optical disturbances (e.g. e.g., irregular astigmatism, but also certain forms of cataract) or repeat subjective refraction); if the stenopeic gap does not improve visual acuity, no precise statement can be made about retinal function, and further search must be made for other causes of vision reduction (see below).
- Swinging flashlight test (literally about “swinging flashlight test”, also pupil alternating illumination test or SWIFT test): alternating illumination of the pupil in an almost darkened room to test for disruption of the afferent limb of the pupillary reflex pathway; pathological, for example, in major retinopathies (retinal diseases) or optic nerve damage of various causes).
- Color saturation comparison of both eyes (e.g., with red bottle head each eye tested separately and immediately right/left of the visual axis).
- Slit lamp examination (slit lamp microscope) of the anterior and middle sections of the eye.
- Ophthalmoscopy (ocular fundus examination) – provides information on the involvement of the papilla (site visible in the fundus where the optic nerve exits the eye) and macula lutea (macula; yellow spot; the area of the retina with the greatest density of photoreceptors (“the point of sharpest vision”))[papilla:
- Optic atrophy (tissue atrophy (atrophy) of the optic nerve).
- Papilledema (swelling (edema) at the junction of the optic nerve with the retina (retinal), which is noticeable as a protrusion of the optic disc); congestion papilla i. d. R. bilaterallyNote: Papilledema but also unilateral in monolateral disease or incipient congestion papilla possible.
- Papillary anomaly (congenital)
Macula lutea:
- Macular disease → further investigations: Optical coherence tomography (OCT), electrophysiology (VEP, ERG and EOG), fluorescein angiography]
- Amsler grating network (functional test that can be used to check the central visual field areas of the eye; right/left respectively with a question about bent lines (rapid screening method that can give an indication of macular disease).
- Tonometry (intraocular pressure measurement)* .
Optional medical device diagnostics – depending on the results of the medical history, physical examination, laboratory diagnostics and mandatory medical device diagnostics – for differential diagnostic clarification.
- Color saturation comparison of both eyes – if mild pathologic SWIFT is suspected (see above )Procedure: the patient is asked to fixate an e.g. red bottle head monocularly while covering the other eye and then compare it with the color intensity of the other eye. With reduced red perception and reproducible result, this difference indicates asymmetric optic nerve disease with weight on the side perceived as weaker red.
- Perimetry (visual field measurement)*
- [Monocular visual field defect = result of a defect of the retina (retina) or optic nerve (optic nerve) to the optic chiasm (optic nerve crossing) of the same side (i.e., the nerve fibers of the lateral retinae lead to the ipsilateral cerebral hemispheres, and the medial nerve fibers cross to the contralateral side)
- Unilateral hemianopic visual field loss (unilateral hemianopsia/unilateral hemianopic visual field loss) = suspected prechiasmal disorder concerning retina, optic nerve, or optic nerve before chiasmNote: If unilateral loss is suspected, very carefully examine the other eye in the outermost periphery with regard to fine external lesions and thus presence of bilateral damage after all, suggesting other causes (i.e., concerning chiasm or postchiasmal pathways after all).
- Binocular visual field defects = damage to the optic chiasm, optic tract and visual radiation to the visual cortex.
- Heteronymous visual field defects/heteronymous (usually bitemporal) hemianopsia: in both eyes, the opposite side is affected by the defect = damage in the optic chiasm.
- Homonymous visual field defects/homonymous hemianopsia (right or left): on both eyes the same side is affected by the failure (contralateral to the lesion) = postchiasmal defect
- Enlarged “blind spot“: papilledema; myopic cone; drusen papilla.
- [Monocular visual field defect = result of a defect of the retina (retina) or optic nerve (optic nerve) to the optic chiasm (optic nerve crossing) of the same side (i.e., the nerve fibers of the lateral retinae lead to the ipsilateral cerebral hemispheres, and the medial nerve fibers cross to the contralateral side)
- Color saturation examination of one eye – when only very mild or unclear visual field defects are suspected, to check whether the deficits are oriented along the vertical midline (is essential criterion for distinguishing diffuse from hemianopic deficits with different neuroanatomical localizations of the lesion (prechiasmal or postchiasmal); here, each visual field hemifield (separated by the imaginary vertical midline) is examined in succession with regard to color saturation (e.g., by means of a red cap of a bottle top).
- Optical coherence tomography (OCT) – imaging technique used in ophthalmology to examine the retina, vitreous and optic nerve.
- Computed tomography of the skull (cranial CT, cranial CT or cCT) – for advanced diagnostics.
- Magnetic resonance imaging of the skull (cranial MRI, cranial MRI or cMRI) – indications:
- Optic atrophy (tissue atrophy (atrophy) of the optic nerve).
- Optic disc edema (swelling (edema) at the junction of the optic nerve with the retina, which is noticeable as a protrusion of the optic disc; congestion papilla i. d. R. bilaterally).
- Suspicion of a lesion in the area of the optic pathway.
* Functional deficits on perimetry usually become apparent only when morphologic damage to the optic disc neuroretinal rim tissue (>40%) is already significantly advanced.
