Refractive errors with myopia greater than 600 degrees (>400 degrees in children) are called high myopia. Because of this type of myopia, most of the eyes have pathological changes.
Clinical manifestations of disease symptoms
(1) Decreased visual acuity.
(2) Rapid development of myopia: Unlike simple myopia, some high myopia continues to develop even into adulthood, so it is also called progressive myopia.
(3) Protrusion of the eye: High myopia is mostly axial, the eye is significantly longer, the anterior chamber is deeper, the ciliary muscle is atrophied, and the eye protrudes outward in some people.
(4) Poor dark adaptation function: The pigment epithelium of the retina is diseased, affecting the photochemical reaction process of the optic cells.
(5) Black shadows in front of the eyes: High myopia can cause vitreous degeneration, liquefaction, and posterior vitreous detachment.
Disease Hazards
The danger of high myopia lies mainly in complications.
(1) Degeneration of the vitreous, choroid and retina due to structural abnormalities and nutritional disorders of the eye.
(2) Atrophy of macular degeneration and posterior staphyloma due to prolongation of the eye axis, scleral elongation, and abnormal biomechanical effects.
(3) Amblyopia and strabismus due to low visual acuity and disorders of convergence function.
Disease treatment Surgical treatment
(1) Corneal surgery At present, excimer laser keratomileusis, especially the application of femtosecond laser, is used to correct high myopia. As for the more distant effect and the impact on the eye tissue remains to be observed.
(2) Anterior and posterior chamber type IOL implantation.
(3) Lens and IOL surgery.
(4) Posterior scleral reinforcement The safety and exact results of this type of reinforcement still need to be further observed.
Other treatments
(1) Wearing glasses, frame glasses and corneal contact lenses.
(2) Laser photocoagulation, condensation or scleral buckling should be performed for symptomatic retinal tears.
(3) Patients with suspected glaucoma who have progressive visual field defects without progressive myopia suggest the presence of glaucoma requiring treatment.
(4) Choroidal neovascularization outside the central or paracentral sulcus can be treated with laser photocoagulation within a few days after fundus fluoroscopy.
Complications
(1) Vitreous lesion
Due to the lengthening of the eye axis, the vitreous cavity is enlarged, which leads to progressive vitreous degeneration, resulting in successive liquefaction, clouding and posterior detachment.
(2) Cataract
Due to abnormalities in intraocular blood circulation and tissue degeneration, the lens can also be involved, mainly manifesting as clouding of the lens.
(3) Glaucoma
The proportion of glaucoma with open-angle glaucoma is six to eight times higher than normal eyes, and the proportion of glaucoma with normal eye pressure and suspected glaucoma is also significantly higher than other people.
(4) Macular lesions
Macular hemorrhage, macular degeneration, macular fissure are common.
(5) Retinal detachment
It is a common complication of high myopia, with an incidence eight or ten times higher than that of other populations. The proportion of primary or foraminogenic retinal detachment can be as high as 70% or more in myopic eyes.
(6) Posterior scleral staphyloma
In myopic eyes with degeneration, the sclera at the posterior pole becomes significantly thinner due to excessive posterior extension of the eye from the equatorial part, and limited dilatation occurs, and under the action of intraocular pressure, the sclera expands and forms posterior scleral staphyloma of various sizes. Its occurrence is obviously related to the level of refraction and the length of the eye.
(7) Amblyopia
(8) Strabismus
Due to the abnormalities and interrelationships between regulation and assembly functions, it is often accompanied by occult exotropia or dominant exotropia.