What are keratoconstrictive lenses?
A keratoplasty lens is a rigid contact lens that is usually worn at night and removed the next morning. The physical shaping effect of the lenses on the eye surface is used to reduce the degree of myopia in the eye and to obtain good naked eye vision. However, this correction of myopia is temporary and long-term nighttime wear is required to maintain good daytime vision.
How do keratocontact lenses work to correct myopia?
Regular contact lenses are soft and have a shape that approximates the shape of the corneal surface, so they have no effect of flattening the cornea. Corneal shaping lenses, on the other hand, are specially designed to apply pressure to the optical area of the cornea, changing the shape of the cornea and flattening it. When the cornea is flattened, the eye’s ability to focus decreases, thus correcting myopia.
Why do keratoconus lenses slow down the progression of myopia?
Blurred images on the fundus of the eye can cause myopia to progress. When wearing regular glasses to correct myopia, the optical aberration of the lens itself causes the central part of the external object to focus on the fundus of the eye, while the peripheral part deviates from the fundus, creating a blurred image that leads to the progression of myopia. With keratoplasty lenses, the optical aberration of ordinary glasses is avoided and the blurred image on the fundus is reduced, thus slowing down the progression of myopia.
What is the fitting process for keratomileusis?
The fitting process follows the following steps.
What are the examination items before the fitting of keratoconus lenses?
These include the following items.
1.Visual acuity test.
2, refraction test, including subjective and objective optometry, children need ciliary muscle paralysis optometry.
3, corneal curvature measurement.
4, corneal topography examination.
5.Corneal diameter measurement.
6.Corneal thickness measurement.
7.Pupil diameter measurement.
8.IOP measurement.
9.Routine examination of the external eye and the anterior segment of the eye.
10.Fundus examination.
11.Eye axis length measurement.
12.Tear film analysis.
13.Other: such as contrast sensitivity, wavefront aberration and other examinations.
Who is suitable for wearing keratoconus?
Suitable for the following groups of people.
1, 8 to 12 years of age or older, progressive myopia, the wearer is more capable of self-care or parents can assist in fitting. under 8 years of age, the wearer needs to be used with caution under close follow-up by an ophthalmologist.
2, myopic spherical lens degree -0.75D ~ -5.50D, the higher the spherical lens degree, the less predictable the shaping effect.
3, Corneal refraction (K value) 40.00D ~ 46.00D, the difference between the corneal flat K value and the expected corrected myopia is more than 36D.
4, <1.5 D cis-regular corneal astigmatism, <0.75 D retro-regular corneal astigmatism; astigmatism less than 1/3 spherical lens degree.
5, larger corneal e value, flatter peripheral part of corneal morphology.
6, central corneal thickness >0.4mm.
7, pupil diameter is normal.
8.IOP is normal.
9, no other eye diseases or history of eye trauma, eye surgery history.
10, good personal hygiene and sanitary habits, able to comply with medical advice.
11, have a reasonable expectation of the correction effect.
Which people are not suitable for wearing keratoconus?
1, myopic spherical lens degree >-5.50D, cis-gauge astigmatism >1.50D, retrogauge astigmatism >0.75D, corneal shape irregularity, with obvious lens astigmatism.
2, corneal too flat ≤ 39.00D, or too steep ≥ 46.00 D.
3, corneal e value ≤ 0.1, corneal spherical, corneal e value and refractive error degree mismatch.
4.The pupil diameter is too large.
5, various eye diseases, such as dry eye, inflammation, glaucoma, proptosis, nystagmus, etc.
6, systemic diseases, such as diabetes, immune system diseases, psychiatric patients, etc.
7, unreasonable expectations of the correction effect.
8.Poor trial wear effect.
9, poor personal hygiene habits, can not adhere to the medical prescription wearers.
10, the elderly, poor corneal compliance, eyelid laxity, poor correction effect.