Keratoconus. Symptoms and the diagnosis
Before any physical examination the diagnosis keratoconus often begins with examination of the ophthalmologist or optician of a case history of the patient, especially main complaint and other visual symptoms, presence of any history of eye illness or a wound which could damage vision, and presence of any family history of eye illness. The eye chart, such as standard chart Snellen of progressively smaller letters, then it is used to spot visual acuteness of the patient. Eye examination can proceed to measuring of the localized curvature of a cornea with a manual keratometer, with detection of the nonregular astigmatism offering possibility keratoconus. Serious cases can exceed ability of measuring of the instrument. The further indication can be given a retinoscopy in which the easy fascicle concentrates on a retina of the patient, and reflection, or a reflex, observed, as the auditor cants a light source back and forth. Keratoconus among eye Conditions which show the scissored reflected activity of two ligaments moving to and far apart as edges of scissors.
If keratoconus it will be suspected, the ophthalmologist or optician will search for other characteristic detection of illness by means of examination of a slit lamp of a cornea. The premature case usually with readiness is obvious to the auditor, and can provide the unequivocal diagnosis before more specialized testing. Under exact examination by a ring yellowy-brown to the brown-green pigmentation known as, ring Fleischer can be observed in approximately half keratoconic an eye, and the gland hemosiderin within a corneal epithelium causes deposition okisi. Ring Fleischer is thin, and cannot be with readiness giving in to detection in all cases, but becomes more obvious when is surveyed under a cobalt blue filter. In the same way approximately 50 % of subjects show striae Vogt's, fine lines of a strain within a cornea caused at a tension and a thinning. striae temporarily disappear, while small pressure is imposed to an eyeball. Very obvious cone can frame indentation V-shaped in lower blepharon when the steadfast view of the patient is referred downwards, is known as sign Munson's. Other clinical symptoms keratoconus will usually appear before sign Munson's becomes obvious, and thus this detection though the classical sign of illness, tends not to have primary diagnostic value.
The portable keratoscope sometimes known as the Keratoscope, can give to the auditor simple noninvasive visualization of a surface of a cornea at designing of some concentric rings of light on a cornea. More exact diagnosis keratoconus can be gained, using corneal topography in which the automated instrument designs the shined structure on a cornea and spots its topology from the analysis of the numeral image. The topographic map specifies any contortions or healing presence in a cornea, with keratoconus, shown to characteristic ukruchivaniem curvature which is usually the lowest to (more low) centreline eyes. The technics can make record of a picture of a degree and strain expansion as a reference point to estimate its norm of a progression. It has specific value in maintenance of detection of disturbance in its early stages when other symptoms yet have not presented.
As soon as presence keratoconus has been erected, its degree can be carried many agents, useful to the auditor:
• a steepness of the most major curvature from soft (<45 D), advanced (to 52 D) or serious (> 52 D);
• cone morphology: a papilla (the small: 5 mm and almost central), an oval (larger, below center and often caving in), or globus (it is more than 75 % of the caused cornea);
• a corneal thickness from soft (> 506 µm) to premature (<446 µm).
The augmentation of use of corneal topography has led to depression in use of these terms by some experts.
|
