Evaluation of axial length/total corneal refractive power ratio as a potential marker for ocular diagnosis of Marfan's syndrome in children.

AIM: To investigate whether the axial length (AL)/total corneal refractive power (TCRP) ratio is a sensitive and simple factor that can be used for the early diagnosis of Marfan's syndrome (MFS) in children. METHODS: The relationship between the AL/TCRP ratio and the diagnosis of MFS for 192 eyes in 97 children were evaluate. The biological characteristics, including age, sex, AL, and TCRP, were collected from medical records. Receiver operating characteristic (ROC) curve analysis was performed to investigate whether the AL/TCRP ratio effectively distinguishes MFS from other subjects. The Youden index was used to re-divide the whole population into two groups according to an AL/TCRP ratio of 0.59. RESULTS: Of 96 subjects (mean age 7.46±3.28y) evaluated, 56 (110 eyes) had a definite diagnosis of MFS in childhood based on the revised Ghent criteria, 41 (82 eyes) with diagnosis of congenital ectopia lentis (EL) were included as a control group. AL was negatively correlated with TCRP, with a linear regression coefficient of -0.36 (R 2=0.08). A significant correlation was found between age and the AL/TCRP ratio (P=0.023). ROC curve analysis showed that the AL/TCRP ratio distinguished MFS from the other patients at a threshold of 0.59. MFS patients were present in 24/58 (41.38%) patients with an AL/TCRP ratio of ≤0.59 and in 34/39 (87.18%) patients with an AL/TCRP ratio of >0.59. CONCLUSION: An AL/TCRP ratio of >0.59 is significantly associated with the risk of MFS. The AL/TCRP ratio should be measured as a promising marker for the prognosis of children MFS. Changes in the AL/TCRP ratio should be monitored over time.

Analysis of Axial Length in Young Patients with Marfan Syndrome and Bilateral Ectopia Lentis by Z-Scores.

INTRODUCTION: Marfan syndrome (MFS) is characterized by ectopia lentis (EL) and elongated axial length (AL). The characteristics of AL in young patients with MFS and bilateral EL before the lens surgery are not fully understood. METHODS: This study reviewed MFS patients under 20 years old with bilateral EL from January 2015 to October 2020. The Z-scores were introduced in terms of the number of standard deviations from the mean of age-matched normative data. Using Z-scores, the distribution of AL and influence factors were evaluated. The correlations between AL and other biometrics were analyzed. RESULTS: We reviewed 183 patients and enrolled both eyes. The mean age was 8.44 ± 4.69 years. About 36% of the patients were children under 6 years old. The median AL increased from 23.16 mm under 5 years old to 26.20 mm in the 16-20 age group, and when plotted, the trend presented a logarithmic curvature (R2 = 0.145, p < 0.001). The median Z-AL score was 1.24. One-third of eyes had Z-score <0. About 20% of the patients had AL difference over 1 mm between the right and left eyes, and the right one had longer Z-AL scores (p = 0.013). The eye complicated with megalocornea (10, 7.04%) had larger Z-AL scores (4.72 ± 3.51 vs. 1.10 ± 2.25, p = 0.002). A positive correlation was found between Z-AL and Z-corneal curvature radius (r = 0.265, p < 0.001). CONCLUSION: Young patients with bilateral EL but small AL should not be excluded from MFS without systematic examination. The age-adjusted Z-score will facilitate further study of the individual variations in AL across different ages.

[Estimation of visual performance of two diffractive multifocal intraocular lenses].

OBJECTIVE: To evaluate the visual performance after implantation of the Tecnis ZM900 multifocal intraocular lens (IOL) (TMF) and the Restor SA60D3 multifocal IOL (Restor). METHODS: In a prospective study, TMF or Restor was implanted randomly in 73 patients (90 eyes). The following parameters were assessed 3 months after surgery: refraction, uncorrected and best corrected visual acuities (VA) for distance, intermediate, near and different contrast levels, reading ability, pupil size, wave-front error, defocus curve and position of IOL. Patient satisfaction (overall satisfaction, spectacle independence, photic phenomena) was assessed by a questionnaire. The chi-square test was applied to compare categorical variables and Mann-Whitney U test was used to compare the measured data. RESULTS: The uncorrected, best corrected and/or distance-corrected VA for distance, intermediate, near and different contrast levels did not show statistically significant differences between the two groups (P > 0.05). Near reading acuity and reading speed were better in TMF under low-light conditions (Z = -2.579, P = 0.009; Z = -5.244, P = 0.000). The curve of defocus showed that TMF had significantly better intermediate distance (at 50 cm) (Z = -5.300, P = 0.000) and worse near distance (from 25 to 28 cm) than those of Restor (Z = -3.745, P = 0.000; Z = -5.691, P = 0.000). Measurements under pupil diameter at 3.0 mm and 5.0 mm, ocular and intraocular Z (4, 0) were significantly lower (Z = -8.175, P = 0.000; Z = -5.210, P = 0.000 and Z = -4.453, P = 0.000; Z = -3.790, P = 0.000), the values of PSF Strehl Ratio and MTF AreaRatio A/D were significantly higher (Z = -3.047, P = 0.002; Z = -3.672, P = 0.008 and Z = -2.038, P = 0.042; Z = -2.579, P = 0.009) in TMF than those in Restor. On the questionnaire, there was no difference of overall satisfaction, spectacle independence and photic phenomena (P > 0.05). CONCLUSIONS: Implantation of the TMF and Restor offers excellent distant and near VA. Restor had better near VA than that of TMF based on the curve of depth, TMF had better VA at 50 cm-distance. Reading speed is faster in TMF. Compared to spherical Restor, TMF provides a better quality of vision due to a negative spherical aberration.

[Clinical study of intraocular lens power calculation methods after cornea refractive surgery].

OBJECTIVE: To evaluate the results of cataract surgery in myopia patients after laser in situ keratomileusis (LASIK) and to compare the predictability of various methods of intraocular lens (IOL) power calculation. METHOD: Seventeen cases (24 eyes) who had LASIK for myopia were divided into two group by with or without history of corneal power data. Corneal power was obtained by autokeratometry, corneal topography, Pentacam and IOL Master. The IOL power was calculated with the clinical history method, Feiz-Mannis formula, Feiz-Mannis method and other methods. Postoperative final refraction and the deviation of the final spherical equivalent (SEQ) from the refractive target were measured 3 month after the surgery. Two sample t-test, linear correlation and regression analysis, paired t-test and Bland-Altman method of agreement were used to analyze these data. RESULTS: In the group with history data, the mean corneal power was (43.28 ± 1.21) D and the mean SEQ was (-15.33 ± 4.36) D before the LASIK surgery. In the group without history data, the mean SEQ was (-10.11 ± 3.12) D. Before cataract surgery, the mean corneal power was (36.96 ± 2.07) D and (36.85 ± 1.40) D in these two groups. The mean arithmetic refractive prediction error after cataract surgery was (-0.66 ± 1.27) D and (-0.47 ± 0.82) D in these two groups, respectively. Data calculated by using Hamed-Wang-Koch method, Masket Formula, Koch/Maloney method, Shammar method and Pentacam ERK method were lower than the emmetropic IOL power. Data calculated by using Feiz-Mannis Formula, Latkany Method, Savini method, Armberri Double K method were overestimated. The mean arithmetic errors of clinic history method, Corneal Passby Method and Haigis-L Formula were not significantly different from the predict refraction (P = 0.364, 0.318 and 0.069; t = 0.956, -1.057 and -1.911, respectively). There was strong correlation between the value calculated by using Feiz-Mannis Method or Haigis-L Formula and the true power (r = 0.921, 0.915; P = 0.000 and 0.000, respectively). But none of the values calculated by these method could fully agree with the true value. CONCLUSIONS: IOL power should be calculated accurately to avoid undercorrection. We recommend the combination of clinical history method, Feiz-Mannis Method, Corneal Passby Method and Haigis-L Formula for the calculation of IOL power.

Visual results and complications of primary intraocular lens implantation in infants aged 6 to 12 months.

BACKGROUND: To present the visual results and the complications of primary intraocular lens (IOL) implantation in infants aged 6 to 12 months between January 2002 and July 2007. METHODS: A total of 26 consecutive eyes, of 16 infants with cataract aged 6 to 12 months, were reviewed in the study. All patients had cataract extraction with anterior and posterior capsulorrhexis combined with anterior vitrectomy and primary hydrophobic acrylic IOL implantation. Six infants (six eyes) had unilateral congenital cataract and ten (20 eyes), bilateral cataract. Visual acuity and complications were recorded throughout the 46.4-month mean follow-up (range 22 to 79 months). RESULTS: All eyes had primary IOL implantation. The mean best-corrected visual acuity (logMAR) was 0.98 +/- 0.18,0.50 +/- 0.14 and 0.61 +/- 0.25 for unilateral, bilateral and all eyes respectively at the last follow-up. IOLs were implanted in the capsular bag of 25 eyes (96.2%) and in the sulcus of the remaining one eye (3.8%). Seven eyes (26.9%) developed visual axis opacification (VAO), and four eyes required secondary pars plana vitrectomy (PPV). IOL opacification occurred in one eye 54 months after implantation. Late onset open-angle glaucoma developed in one eye, and required trabeculectomy surgery. The predictors of good best-corrected visual acuity (BCVA) included partial cataract, bilateral cataract, absence of strabismus or nystagmus, and good amblyopic treatment. The greatest annual myopic change (5.15 +/- 2.08 D) was observed during the first 12 months after surgery. In unilateral cases, there was no significant difference in the axial length between the cataractous eye and the fellow normal eye both at the time of surgery (P = 0.891) and final follow-up (P = 0.693). CONCLUSIONS: Primary IOL implantation was safe and effective for infantile cataract surgery. Total or unilateral cataract, nystagmus or strabismus, and inadequate amblyopic therapy were predictors of poor BCVA. Significant myopic shifts occurred especially in infants in the first year of surgery. The pseudophakic eye had a similar growth rate, as measured by axial length, to that of the fellow normal eye, in unilateral cases.

[To pay attention to clinical limitations of accommodative and multifocal intraocular lens].

Clinical application of accommodative and multifocal intraocular lens (IOL) were comparatively successful in recent years. However, we must notice the limitations of these kinds of IOL and the related clinical problems, such as very limited accommodative ability of accommodative IOL and glare or haloes and reduced contrast sensitivity of multifocal IOL. We must pay attention to these clinical problems from these IOL and the unexpected prognosis of these kinds of lens. We must choose the indications strictly, and avoid the misuse.

[Phacoemulsification and the negative power of intraocluar lenses in extremely myopic eyes].

OBJECTIVE: To evaluate the clinical effects of phacoemulsification and the negative power of intraocluar lens implantation in patients with extreme myopia and cataract. METHODS: 89 patients (126 eyes) received phacoemulsification and a negative power intraocluar lens implantation. Preoperative axial length, postoperative visual acuity and refractive error were recorded. Intraoperative and postoperative complications were observed. The follow-up time is from 6 to 25 months. RESULTS: The mean preoperative axial length is 32.45 mm. Best corrected visual acuity achieved 0.2 or better in 106 eyes (84.1%) and 0.5 or better in 69 eyes (54.8%). Of the 126 eyes, 56.3% were within 1.00 diopter (D) of refractive error and 90.5% were within an error of 2.00 D. Only 1 eye has posterior capsule rupture. 28 eyes had binocular disturbances. 15 eyes developed posterior capsule opacification and 6 eyes were performed neodymium: YAG laser posterior capsulotomy. No retinal or choroidal detachment or pressure improvement was seen during the follow-up. CONCLUSION: It is safe and effective for extreme myopia with cataract to implant a negative power intraocular lens after phacoemulsification.