ABSTRACT
AIM: To investigate the proportion and characteristic of emmetropia in schoolchildren aged 6-11, especially estimate the normal value of ocular biometric parameters of emmetropia. METHODS: A population-based cross-sectional study was conducted on children aged 6-11y in Shenzhen. Totally, 2386 schoolchildren from two primary schools were involved. The axial length (AL) and the corneal radius of curvature (CRC) were measured by partial coherence laser interferometry. Noncycloplegic refraction and refractive astigmatism (RA) was measured using autorefraction. The axial length-to-corneal radius of curvature ratio (AL/CRC), corneal astigmatism (CA) and spherical equivalent refraction (SER) were calculated. RESULTS: The proportion of emmetropia in elementary school students was 41.30%. This percentage decreased gradually from 6 to 11 years of age and decreased rapidly after 9 years of age. The mean and 95%CI of each parameter were provided for boys and girls aged 6 to 11 years of age with emmetropia according to each age group. The change trend of parameters of boys and girls are similar. After 7 years of age, the AL of non-emmetropia started to increase faster than that of emmetropia. The change trend of AL/CRC was the same as that of AL. The other parameters tend to be stable after 7 years of age. CONCLUSION: The age of 7-9 is an important period for the changes of refractive state and ocular biometric parameters of primary school students, and it is a special focus period for children myopia prevention. The normal value and variation of ocular biometric parameters of emmetropia can provide the basis for the clinical judgment of whether or not children's ocular biometric parameters obtained by single measurement and changes obtained by multiple measurements are abnormal.
ABSTRACT
AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intended ï¬ap thickness was 110µm and 160µm respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45° and 135° meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43±4.70µm, while 125.90±17.50µm in the Hansatome group. The difference between the actual and the expected ï¬ap thickness was 5.61±3.84µm and 31.52±12.27µm, respectively. The Hansatome group had presented a statistically signiï¬cant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.
ABSTRACT
OBJECTIVE: To evaluate the efficacy of surgical treatment for encapsulated cystic blebs around the plate after Ahmed glaucoma valve implantation. METHODS: This was a retrospective observational case series. Thirteen cases with elevated intraocular pressure (IOP) induced by fibrous proliferation around Ahmed valve were retrospectively studied. The intraocular pressure increased at 3 weeks to 5 months post-operation (2 months in average). The plates and tubes of Ahmed valve were in good position. No obstruction was seen in the tubes. Localized, encapsulated, cystic blebs were found in the equator of eyeball in which the plates were located. All cases underwent encapsulated cysts resection combined with mitomycin-C usage under conjunctival flaps. The excised tissues were sent for pathological examination. The changes of IOP and the outcome of the diseases were observed. RESULTS: IOP was normal one month after surgery in all cases. The success rate was 100%. In the 3 - 20 months follow-up period, the IOP level kept normal in 3 cases without any anti-glaucoma medications. The IOP level was in normal range in 6 cases using two or three different kinds of anti-glaucoma medications. Three cases needed further surgical treatment because of uncontrolled IOP even with anti-glaucoma medications. Among them, the complete success rate was 75% (3/4) in patients more than 57 years old, while the complete success rate was 0 (0/8) in patients less than 37 years old. CONCLUSIONS: It was considered an effective method of surgical treatment for encapsulated blebs around Ahmed glaucoma valve. The result was better in elderly patients than in younger patients relatively.
