| Myopia is one kind of common oculopathy. According to thecourse of illness progress and whether there is the pathological change,it divides into the pathological myopia (PM) and the benign myopia(BM). The pathological myopia has many characteristics: appearing inchildhood;developing continually, obviously in the puberty, andbecoming more static relatively when grow up;the dioptric strength isoften upper than -6.00D;the eye axis obviously lengthens, the lengthhas the direct ratio to the dioptric strength;pathological change of theeye ground appears early time, including the conus, the pigmentepidermis thinly changes, the leopard grain shape eye ground, theFuchs spot, the retina choroids withers and so on, and all these willturn to aggravate;the function obviously suffering injury;havingmany complications, such as amblyopia , hyaloid cataract, ablatioretinaeis and so on. There is more than 200 years since we became researching theaetiology of pathological myopia, although so far still could notinvestigate thoroughly, but the cause of it at least included the raceheredity factor, the environmental factor, and involved the eye thedissection, the physiology, the blood supply, and the autonomicnervous system, the immunity system, the endocrine system and soon.The inherited factor and the environmental factor are primarily.The study of colonia and family survey showed that pathologicalmyopia has many modes of inheritance, including the autosomalrecessive or dominant inheritance, the X-linked inheritance. And it hasgenetic heterogeneity highly. The autosomal recessive inheritance ispossibly the most common mode, while the X-linked inheritance is theleast one. At present we has discovered five mutants of genetic locus:MYP1 (Xq28, the X-linked recessive inheritance), MYP2 (18p11.31,the autosomal dominant inheritance), MYP3 (12q21-q23, theautosomal dominant inheritance) and 7q36 and 17q21-q23 whichdiscovered recently (both of the autosomal dominant inheritance).Studies also discovered PM and HLA have the relevance, and certainneurotransmitters have also take part in the occurrence anddevelopment of the pathological myopia. The genetic factor plays adecisive role in the occurrence and development of the pathologicalmyopia, and the environmental factor also plays a vital role as theexternal factor. Some environmental factors we have known, includingworking in a short distance, the reading custom, the habitually usedlight, form-deprivation, the insufficient of microelement and so on, allplayed the varying roles. At present we still have not a theory toexplain and to explain the pathogenesy of the pathological myopiawhether internal or abroad. There were tow theories mainly, theaccommodate theory and the form-deprivation theory. With thedevelopment of science and technology, these two theories alsounceasingly improved. We can believed that the development ofadvancing front science will impulse the pathogenetic study of thepathological myopia in future, such as genic array, genetic engineering,and be able to reveal the concrete pathogenesy of pathological myopia,find effective methods to prevent and cure.It seemed to be a tough problem to prevent and cure the myopiafor medical scientists in the world. The methods to correct myopia areusually divided into three kinds: (1) The lens rectify: including frameeyeglasses and corneal lens;(2) Cornea surgery: radial keratotomy(RK), photorefractive keratectomy (PRK), laser in situ keratomileusis(LASIK) and so on;(3) Intraocular surgery: crystal extraction,artificiallens insertion and so on. In recent years the invention, innovation anddevelopment of various refraction operations have become the studyhot spot for treating myopia. At present, LASIK is used most widly inclinical. its principle is using excimer laser to cut the corneaorganization accurately, adjust the curvature and remold the refractingpower of the cornea, which can cause the light to focus on the retinathrough the cornea remolded. So we can again attain the clear nakedvisual acuity. LASIK has many prominent merits, such as betterconsistent with physiological structure of the cornea, morecomfortable after surgery, the wound healing and the vision recoveringmore quickly, having hase scarcely, without using excitatory autacoidlong time, larger extent to correct, less to retreat and so on.It turned tobe the main method to correct the myopia.Objective: to observe the efficacy of LASIK for treatment ofmyopia.Materials and methods: we chose 57 patients, 114 eyes whichaccept the LASIK treatment during June of 2004 to August of 2004.According to spherical equivalent (SE), they were divided into twogroups. All patients were examined strictly before surgery and no onehave any surgical contraindication. The surgery used Allegretto Wave1009 excimer laser system, which provides the initiative eyeballtracking system with infrared guiding.The facula diameter of laser is0.95mm. Laser distributed as Gaussian, and the wave length is193nm.The transmitting frequency is 200Hz.The energy density is1.33~1.35mJ/cm2. The diameter of optics zone is 6.0~7.0mm, whilediameter of treatment zone is 7.1~9.0mm. At the 1st day, 7th day, amonth, 3 months postoperation, we made analysis in uncorrectedvisual acuity(UCVA), SE, slit lamp, the cornea topography of thesetoe groups.Result: (1) the UCVA of two groups have obvious elevationcomparing the BCVA preoperation. (2) at 3 months, 96.67% and92.59% had uncorrected visual acuity of 1.0 or better. (3) at 3 months,the residal refractive error within ±1.0D were 96.67% in group A, and85.19% in group B. (4) the two groups of patients did not have anyserious complication ,such as the night vision decreasing, dazzle andso on. Conclusion: the LASIK surgery can remarkably enhancepatients' naked vision, and the clinical effect is good in the near future.The LASIK surgery in lower myopia has stable effect,goodpredictability and the patients restore quickly after operation.While thehigher myopia restores slightly slowly, and the vision and the diopterhave slight fluctuation in 3 months after operation. The decentrationcan be reduced by using a scanning-spot laser system with active eyetrackin system. The formation rate of dazzle is obviously reduced withlarger zone. The efficacy for treating supper-myopia upper -1.0D willbe observed further.
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