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PubMed2003

[Retrospective evaluation of eyes with high progressive myopia in children and youth ten years after Snyder and Thompson's scleroplasty].

PURPOSE: Of the study was, to assess the safety and efficiency of scleral reinforcement after Snyder and Thompson surgery. MATERIAL AND METHODS: The scleroplasty was performed on 129 eyes of 75 children with progressive myopia from 6 to 10 years of age. The control study group included 40 eyes of 25 children with similar age, mean eyeball axial length and refraction. In the control study group scleroplasty was not performed. The main indication criteria for surgery included: severe myopia more than -6.0 D, and the increase in refraction error more than -1.0 D per year. We evaluated the eyeball axial length in all subjects, before time of surgery and ten years after surgery, using Ultrasound Alcon Imaging System. The visual acuity, tonometry, visual field were evaluated as well. RESULTS: In the study group the mean eyeball axial length measured before surgery was 25.95 mm +/- 0.62 mm. Ten years after surgery the length of the eyeball was 26.97 mm +/- 0.64 mm. The average increase was 1.03 mm +/- 0.29 mm. In the control group, at the time when study group children were operated, the mean eyeball axial length was 25.91 mm +/- 0.48 mm, and ten years later it was 28.06 mm +/- 0.59 mm. The average increase in the eyeball length was 2.13 mm +/- 0.3 mm. There was statistically significant difference between the eyeball axial length progression in the study group and the control group, where surgery was not performed. In the study group no serious complications after surgery were reported. CONCLUSIONS: Scleral reinforcement is an effective and safe surgery, that can stabilize the progression of severe myopia in children.

Adolescent↗
PubMed2003

Posterior chamber phakic intraocular lens implantation for high myopia.

OBJECTIVE: To evaluate the efficacy, safety and stability of posterior chamber phakic intraocular lens (PIOLs) implantation for the correction of high myopia. METHODS: Thirty-nine eyes of twenty patients with high myopia (between -11.75 and -25.75 diopters) had a posterior chamber PIOL (Staar ICL) implanted. During 6 - 48 months' follow-up, visual acuity, refraction, intraocular pressure (IOP), corneal reaction and space between crystal lens and intraocular lens (IOLs) were tested. RESULTS: Successful implantation was achieved in all patients. Visual acuity without correction greater than 0.5 was found in 34 eyes at 1 day and 3 months postoperatively. Thirty-five eyes maintained a low negative power of refraction (-1.42 +/- 1.32 doipters), which did not prevent the patients from most of their daily activities. During 3 - 48 months' follow-up, refraction was stable and no cornea edema and glaucoma was found. Two eyes of one patient had corticosteroid glaucoma and another eye showed cataractogenesis under anterior capsular membrane. CONCLUSION: Posterior chamber PIOL implantation is predictable, safe, and effective in the correction of high myopia, and its indications should be carefully selected.

Adult↗
PubMed2003

[Myopia and childbirth].

We made a study of 106 women in childbirth from our hospital with myopia for the period from 2003 to 2003. Vaginal delivery have had 38 and Cesarean delivery 68 (64.2%). Only 18 women have had severe myopia (more than 6 d.), which is equal to 17%. We consider that the myopia is an ungrounded common indication for Caesarian section.

Adult↗
PubMed2003

[The visual outcome and related factors in cataract patients with extreme myopia].

OBJECTIVE: A prospective study was performed to analyze the visual outcome and factors related to the visual outcome in cataract patients with extreme myopia, in order to provide a principle for intraocular lens (IOL) diopter chosen. METHODS: 43 cases were included in the present series (myopia over 10.00 D, axial length over 27.00 mm, with clear cornea and slight or moderate opacity of the lens). Distance and near visual acuity (NVA), best corrected visual acuity and the fundus were examined before and after the phacoemulsification and implantation of IOL. chi(2) test and stepwise regression analysis were used to identify the predictive factors. RESULTS: (1) Distance visual acuity, NVA and best corrected visual acuity were markedly improved in most cases. (2) NVA and fundus pathologic changes were two important factors for predicting post-operative visual acuity. (3) The prognosis was better in cases with NVA better than 20/200, and in cases with axial length below 29.00 mm. (4) Some cases with postoperative NVA worse than 20/80 complained of difficulty in reading. CONCLUSIONS: NVA is an important factor influencing the outcome of vision and is an important parameter for predicting the outcome of vision in cataract patients with extreme myopia. IOL diopter should be determined carefully by preoperative NVA and the patients' demand for near work.

Adult↗
PubMed2004

Using natural STOP growth signals to prevent excessive axial elongation and the development of myopia.

Myopia is emerging as a major public health issue due to its increasing prevalence and long-term pathological outcomes. Prevention must focus on limiting excessive axial elongation which is the cause of both myopic refractive error and its pathological outcomes. The increasing prevalence appears to be due to environmental changes involving near work, rather than to a genetic failure of emmetropisation. Attempts to control the progression of myopia optically have been unsuccessful; the only available preventive regime involves the use of atropine eye drops. This regime has short-term side effects, and since the site and mechanism of action of muscarinic antagonists are unclear, there are concerns about its long-term safety. Recent studies on natural STOP growth signals suggest that they are evoked by relatively brief periods of imposed myopic defocus, and can overcome strong pressures towards increased axial elongation. While STOP signals have only been successfully used in chickens to prevent excessive axial elongation, similar signals are generated in mammals and non-human primates. Further studies may define the conditions under which this approach could be used to prevent the development of myopia in humans.

Accommodation, Ocular↗
PubMed1992

[Can progression of myopia be prevented? A literature review].

There is no simple explanation as to when or how myopia commences, nor is there any simple method of preventing the progression of myopia. Non-surgical methods have been attempted: sight training, exercise, drugs to induce cycloplegia and to reduce intraocular pressure, as well as contact lenses and bifocal glasses; none of these have been able to prevent progression. Promising results have been disappointing when these treatments are repeated on larger groups of patients without investigator bias. Surgical procedures for the prevention of progression are not carried out in Denmark at present. New methods of reinforcing the scleral wall also in low grade myopia have been reported from Moscow. Compounds are being injected and transplants are being inserted behind the eye. It is exciting to see whether these results can be reproduced, if trial of this type of treatment is permitted in Denmark.

Humans↗
PubMed2004

[Effects of flashing light on ocular growth and development of myopia in pigmented guinea pigs].

OBJECTIVE: To investigate the effects of flashing light exposure on ocular growth and development of myopia in guinea pigs. METHODS: Thirty 4-week-old pigmented guinea pigs were randomly divided into three groups. Animals in group I were reared with the flashing light continuously and lasted for 6 weeks. The flashing frequency was 15 times per minutes and every flash includes 2 seconds light on and 2 seconds dark. Animals in group II and III were reared with normal light on, and the illumination cycle was 12 hours light/12 hours dark in group II and 24 hours light in group III. After 6 weeks, the effects of flashing light on eye development were assessed by cycloplegic retinoscopy, a-scan ultrasonography and eye weight. The histopathology changes of sclera, choroids and retina in posterior pore of the eye were examined using light microscope and transmission electron microscope. RESULTS: At the end of the treatment period, guinea pigs reared in flashing light exhibited -7.00 D myopia, eye axial elongated 0.56 microm, and the weight increased 68 mg. The histopathology examination showed that the posterior sclera fibroblast become more active, the cell number increased, and the place between fibers became larger, the posterior choroids became thinned, and the outer membrane of photoreceptor cells became shorter and irregular, when compared with the control groups. CONCLUSION: Flashing light can promote ocular growth and induce myopia in pigmented guinea pigs.

Animals↗
PubMed2004

[Assessment of blood flow in eye arteries in patients with myopia and glaucoma].

PURPOSE: To assess blood flow in eye arteries in patients with myopia and POAG. MATERIAL AND METHODS: Doppler ultrasonography was performed in 17 patients with myopia and POAG. The following parameters were statistically analyzed: ophthalmic artery Vs (Vs OA), ciliary arteries Vs (Vs CA), central retinal artery Vs (Vs CRA) and compared to a group of myopic eyes with no POAG and a group of emmetropic eyes with no POAG. RESULTS: Statistically significant decrease of Vs in all analyzed vessels was detected as compared to normal age ranges (a group of emmetropic eyes with no POAG). Statistically significant decrease of Vs in OA and CRA was detected as compared to Vs in myopic eyes with no POAG. CONCLUSIONS: Statistically significant decrease of Vs in patients with myopia and POAG indicates poor perfusion in eye ball vessels.

Adolescent↗
PubMed2004

[Evaluations of extreme myopia correction with phakic posterior chamber intraocular lens and laser in situ keratomileusis].

PURPOSE: To compare and evaluate the efficacy, safety and stability of extreme myopia correction with Phakic Posterior Chamber Intraocular Lens (PPCIOL) Keratomileusis (Lasik). and Laser in situ METHODS: This prospective study enrolled 43 cases of extreme myopia. The PPCIOL group was inserted Implantable Contact Lens (ICL) and Lasik group was done excimer laser scanning. The efficacy index and safety index were compared. The rate of regression postoperative was observed and the changes of low contrast vision and Glare vision were statistically studied. RESULT: The mean spherical equivalent refraction of PPCIOL was (-16.77+/-3.37)D(-11.75 approximately -25.75 D)and that of Lasik was (-13.8+/-2.71) D (-9.37 approximately -23.75 D). There was no statistically difference between efficacy index of two groups postoperatively and a significant higher safety index in PPCIOL(P < 0.001) . The rate of regression was 0 in PPCIOL group and 32.56% in Lasik group (P< 0.001). The increase of low contrast vision and Glare vision from the baseline preoperative was more significant in PPCIOL group than which in Lasik group (P < 0.001). Two eyes of 1 PPCIOL case had anterior capsular cataract in 6 months postoperative. No other complication was found in two groups. CONCLUSION: PPCIOL implantation is an efficient method for extreme myopia correction with more safety and stability, and provides good visual quality.

Adolescent↗
PubMed2005

[Pedigree study of pathological myopia].

90 pedigrees including 1822 individuals were investigated and analyzed to find out the genetic mode of pathological myopia in Chinese population. 169 screened nuclear pedigrees from the total were divided into two groups according to mating mode, Affected * Normal or Normal * Normal. Simple segregation analysis on A * N and N * N pedigrees was performed respectively. The results showed that A * N pedigrees fit the autosomal dominant inheritance, with segregation ratio 0.6033 and sporadic proportion 13.8%, while N * N pedigrees fit autosomal recessive inheritance, with segregation ratio 0.235245 and sporadic proportion 16.3%, although autosomal dominant inheritance could not be rejected. In complex segregation analysis,SAGE-REGD software was used to fit several genetic model, including Mendelian inheritance (major gene, dominant, recessive, codominant) and non-Mendelian inheritance (non-transmitted, environment, general), and at last all Mendelian inheritances including major gene, dominant, recessive, codominant inheritance were accepted, while codominant inheritance with minimus AIC was best fitted. Our study manifests that pathological myopia in Chinese population fits autosomal dominant and autosomal recessive inheritance with certain sporadic proportion, which demonstrates the high genetic heterogeneity of pathological myopia.

Chromosome Segregation↗
PubMed2003

[Effects of nitric oxide on form-deprivation myopia in chicks].

OBJECTIVE: To construct a chick model of form-deprivation myopia (FDM) to investigate the effect of nitric oxide (NO) on FDM. METHODS: FDM was induced in 60 one-day white leghorn chicks. They were divided into group A and B. One eye was covered randomly, and the other served as control. In each week of the experimental period, the retinoscopic refraction was performed, and the axial length was measured with A-mode ultrasound. The NO concentration of retina and choroid from the control and the experimental eyes was measured using NO detection kit. Change in the expression of iNOS mRNA was measured by RT-PCR. The activity of iNOS was analyzed with immunohistochemistry. RESULTS: Form-deprivation eyes were significantly more myopic than the controls, and the axial length of occluded eyes was significantly longer than that of the controls. Unocclusion attenuated the development of myopia and inhibited the axial elongation. Form-deprivation reduced the NO concentration ,the immunoreactivity of iNOS, and the expression of iNOS mRNA. The gradual restoration of normal vision was found after uncovering the eyes. But the expression of iNOS mRNA was significantly higher than that of the controls at the first week after the unocclusion. CONCLUSION: Form-deprivation can construct an animal model of myopia. FDM is reversible before the chicks were mature. NO may be involved in the form of FDM.

Animals↗
PubMed2005

[The mechanism and application of the correction for spherical myopia using small beam excimer laser].

In the laser ablation refractive surgeries, the corneal ablation model and its realization by laser are difficult to design. They greatly affect the results of those surgeries. This paper firstly presents a mathematical model for corneal ablation to correct the refractive error of spherical myopia, and then gives a technique of planning laser focus positions on cornea to realize the ablation model. Based on the principle of the correction for spherical myopia using small beam laser, our excimer laser corneal surgery system has been able to perform such refractive surgery. Now the corneal surgery system has been applied to clinical practice. Thirty-nine eyes with spherical myopia underwent LASIK using this kind of system. Their refractive states have been greatly improved. Preoperatively, the mean sphere was -5.57+/-2.95 D and the mean uncorrected visual acuity 0.12+/-0.07. One day after surgery, the mean sphere was -0.03+/-0.57 D and the mean uncorrected visual acuity 0.90+/-0.29. One month after surgery, the mean sphere was -0.68+/-0.98 D, and the mean uncorrected visual acuity 1.0+/-0.26.

Humans↗
PubMed2005

[Selection of animal model in myopia research].

Animal model plays an important role in myopia research. However discrepancy and deputed have been existed in animal model making, including animal selection, myopia inducing methods. The model selection can not only determine the success of experiments but also impact the accuracy of study outcome. Here are summaries and comments round disputed issues which are hoped to be useful for animal myopia researches.

Animals↗
PubMed2006

[Implantation of phakic anterior chamber intraocular lens for the correction of severe myopia].

OBJECTIVE: To evaluate the efficacy, safety, and predictability of the implantation of phakic anterior chamber intraocular lens (PAC-IOL) for the correction of severe myopia. METHODS: In this prospective study, 15 cases (29 eyes) with myopia at -15.00 - -24.50 dioperts (D) were implanted with Phakic 6H(2) PAC-IOL. Visual acuity, refraction, intraocular pressure, corneal endothelium, the PAC-IOL position, contrast sensitivity, glare sensitivity, operative complications and poor visual symptoms were observed. RESULTS: Postoperative uncorrected visual acuity 0.5 or better was presented in 79.3% eyes (23/29) at 3 months and in 82.6% eyes (24/29) at 6 months. Best corrected visual acuity 0.8 or better was presented in 69.0 % eyes (20/29) at 3 months and in 69.0% eyes (20/29) at 6 months, they were all significantly better than that of preoperative values (P < 0.05); and there was no statistically significant difference between visual acuity at 3 months and 6 months (P > 0.05). Compared with preoperative best corrected visual acuity, postoperative uncorrected visual acuity improved 2 lines or more in 70.0% of eyes (20/29) at 3 months and 72.4% eyes (21/29) at 6 months. The mean postoperative spherical equivalent refraction was -1.00D at 3 months, -1.00D at 6 months, they were significantly lower than that of preoperative values (P < 0.05); and there was no statistically significant difference of spherical equivalent refraction between 3 months and 6 months (P > 0.05). There were no statistically significant difference between pre- and post-operative mean intraocular pressure, corneal endothelial density (P > 0.05) at 3 and 6 months. There was no significant difference of these data between 3 months and 6 months (P > 0.05). The PAC-IOL was located (2.341 +/- 0.116) behind the central cornea, (0.841 +/- 0.140) mm in front of the crystalline lens. The footplates appeared to be correctly positioned in the anterior chamber angle in all eyes. Contrast sensitivity and glare sensitivity in all spatial frequencies increased at 6 months post-operatively as compared with those of preoperative values (best spectacle-corrected) (P < 0.05). Postoperative complications included a slight inflammatory deposits on the PAC-IOL surface at 3 months in 10.3% eyes (3/29) and 6.9% eyes (2/29) at 6 months; oval pupil in 10.3% eyes (3/29); PAC-IOL rotation in 27.6% eyes (8/29); night glare in 17.2% eyes (5/29); all of the other patients were satisfied. CONCLUSIONS: PAC-IOL implantation for the correction of severe myopia is effective, safe and predictable. It can be a supplement for corneal refractive surgery, but follow-up is still required for the evaluation of long-term results.

Adolescent↗
PubMed2006

[Apoptosis and c-myc protein expression in the retinal of form-deprivation myopia].

OBJECTIVE: To study the apoptosis of retina and the expression of c-myc protein in form-deprivation myopia. METHODS: Two-day-old chickens were sutured with right eyelid for 4, 8 and 12 weeks. After measurement of refracation, the eyeballs were observed by light microscope and taken photos. Retinal apoptotic cells were measured by TUNEL staining and flow cytometry. C-myc protein were examined by immunohistochemistry and flow cytometry. RESULTS: Lacquer crack lesions were found in sutured eyes at 12 weeks. Apoptotic cells were observed in retinal outer and inner nuclear layer of the sutured eyes at 12 weeks and obvious peak of apoptosis was observed in sutured eyes at 12 weeks. The expression of c-myc protein was significantly more than control eyes at 8 and 12 weeks. CONCLUSION: The apoptosis of retinal was present in form-deprivation myopia with the degeneration of retina. C-myc protein plays an important role in retinal apoptosis of myopia.

Animals↗
PubMedDate not supplied

[Ophthalmological assessment of professionally significant functions in persons undergone laser myopia correction].

Professionally significant functions (visual acuity, color vision and its parameters, and dark adaptation and its parameters) were determined in moderate and severe myopia before and after its excimer laser correction by the LASIK method: in early (1, 3 months) and late (6, 12 months) periods after surgery to decide where the operated persons are allowed to have the jobs associated with railway traffic safety. Sixty-one patients with moderate and severe myopia and 23 control individuals were examined at the Moscow Research and Technological Complex "Eye Surgery". The examinations have demonstrated that the values of visual acuity, color vision, and dark adaptation considerably improved. Whether the persons undergone excimer laser myopia correction are allowed to have the jobs associated with railway transport safety should be individually decided, by taking into account the postoperative recovery of professionally significant visual functions.

Adolescent↗
PubMed2006

Genome-wide scan of additional Jewish families confirms linkage of a myopia susceptibility locus to chromosome 22q12.

PURPOSE: A genome-wide scan was previously reported for myopia in Ashkenazi Jews. In order to confirm the previous linkage peaks, a collection of DNA samples from 19 new Ashkenazi Jewish families were tested for linkage in a genome wide scan. METHODS: Families were ascertained from an Orthodox Ashkenazi Jewish community through mailings. Myopia was defined as equal to or greater than -1 diopter in both meridians in both eyes. The genome wide scan used markers from a modified Cooperative Human Linkage Center version 9 (402 markers). Parametric two-point linkage was calculated with FASTLINK while multipoint linkage was calculated with GENEHUNTER. RESULTS: The results for the 19 families demonstrated several regions of suggestive linkage on chromosomes 7, 1, 17, and 22. A combined analysis of the 19 families and 44 previously reported families demonstrated an increase in the LOD score to 4.73 for the chromosome 22 locus. CONCLUSIONS: Multiple chromosomal regions have exhibited some evidence of linkage to a myopia susceptibility gene in this Ashkenazi Jewish population. The strongest evidence of linkage to such a susceptibility gene in these data is on chromosome 22.

Adolescent↗
PubMed2006

[The roles of AC/A ratio and other ocular motor parameters in the induction of late-onset myopia].

OBJECTIVE: This study was to explore ocular motor parameters (accommodation and convergence) in late myopia onset and development. METHODS: Eleven Emm (emmetrope), 14 S.M. (stable late-onset myopia), and 9 P.M. (progressing late-onset myopia) were include in this study. Phoria at distance and near, positive and negative relative accommodation (NRA/PRA), accommodative convergence and accommodation response were measured. RESULTS: Response AC/A ratio of P.M. was higher than that of Emm or S.M. (P < 0.05); But statistically AC/A ratio was not significant difference (P > 0.05). Accommodation response (3.00 D) of Emm was higher than P.M and S.M (P < 0.05). There was significant difference in phoria in near between LOM and Emm, but none in that of distance. There was no significant difference in NRA. However, PRA of LOM was lower than that of the Emm (P < 0.05). CONCLUSIONS: Ocular motor parameters are important in LOM onset and development. Response AC/A ratio (not calculated AC/A ratio) is one of key parameters among them, Response AC/A ratio is the highest in P.M, which indicates out of focus of retinal image in the developing LOM.

Accommodation, Ocular↗