Factors affecting long-term myopic regression after corneal refractive surgery for civilian pilots in southwest China.

BACKGROUND: The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term myopic regression. METHODS: We included civilian pilots who had undergone CRS to correct their myopia and who had at least 5 years of follow-up. We collected retrospective data and completed eye examinations and a questionnaire to assess their eye habits. RESULTS: A total of 236 eyes were evaluated in this study. 211 eyes had Intrastromal ablations (167 eyes had laser in situ keratomileusis, LASIK, 44 eyes had small incision lenticule extraction, SMILE) and 25 eyes had subepithelial ablations (15 eyes had laser epithelial keratomileusis, LASEK and 10 eyes had photorefractive keratectomy, PRK). The mean preoperative spherical equivalent (SE) was - 2.92 ± 1.11 D (range from - 1.00 to -5.00 D). A total of 56 eyes (23.6%) suffered from myopic regression after CRS. Comparisons of individual and eye characteristics between the regression and non-regression groups revealed statistically significant differences in age, cumulative flight time, postoperative SE (at 6 months and current), uncorrected visual acuity (UCVA), accommodative amplitude (AA), positive relative accommodation (PRA), postoperative period, types of CRS and eye habits. Generalized propensity score weighting (GPSW) was used to balance the distribution of covariates among different age levels, types of CRS, cumulative flying time, postoperative period and continuous near-work time. The results of GPS weighted logistic regression demonstrated that the associations between age and myopic regression, types of CRS and myopic regression, continuous near-work time and myopic regression were significant. Cumulative flying time and myopic regression, postoperative period and myopic regression were no significant. Specifically, the odds ratio (OR) for age was 1.151 (P = 0.022), and the OR for type of CRS was 2.769 (P < 0.001). The OR for continuous near-work time was 0.635 with a P value of 0.038. CONCLUSIONS: This is the first report to analyze myopic regression after CRS in civilian pilots. Our study found that for each year increase in age, the risk of civilian pilots experiencing myopic regression was increased. Intrastromal ablations had a lower risk of long-term myopia regression than subepithelial ablations. There is a higher risk of myopic progression with continuous near-work time > 45 min and poor accommodative function may be related factors in this specific population.

[Observational Comparison of the Safety and Effectiveness of Myopic Children Wearing Defocus Incorporated Soft Contact Lenses or Orthokeratology Lenses].

Objective: To observe and compare the effectiveness and safety of controlling myopia in children by wearing defocus incorporated soft contact (DISC) lenses or orthokeratology (OrthoK) lenses. Methods: A total of 75 children who came to our hospital between January 2018 and September 2020 were enrolled for this retrospective study. The DISC group consisted of 30 myopic children (60 eyes) wearing peripheral defocal soft incorporated contact lenses during daytime. There were 10 males and 20 females aged (9.9±1.00) years old in this group and their spherical equivalent refractions were (-2.78±0.70) D. The OrthoK group consisted of 45 myopic children (90 eyes) wearing OrthoK lenses. There were 30 female and 15 males aged (9.67±1.11) and their spherical equivalent refractions were (-2.67±0.71) D. All subjects had previously worn prescription glasses for 12 months or longer before they started wearing contact lenses. The subjects were followed up for 12 months once they started wearing contact lenses. The axial changes and corneal and conjunctival complications of the two groups of myopic children were compared and analyzed. Results: Myopic children in both groups experienced relatively rapid increase in ocular axial length while they were wearing prescription glasses, with the ocular axial length increase in the prescription-glass-wearing period being (0.34±0.09) mm in the OrthoK group and (0.37± 0.07) mm in the DISC group. In the 12 months of wearing contact lenses, the ocular axial length of children in the OrthoK group increased by (0.18±0.04) mm, while that of the DISC group increased by (0.19±0.05) mm. The increase in ocular axial length was reduced in both groups after the children were switched to the new myopia prevention methods, showing significant difference ( P<0. 05). The two groups using two different contact lenses had similar axial length increase, showing no significant difference ( P>0.05). During the 12-month period while the subjects wore the two types of contact lenses, the incidence of chronic follicular conjunctivitis was 11.20% in the OrthoK group and 20.00% in the DISC group, with that of the DISC group being slightly higher without showing significant difference ( P>0.05). The incidence of grade-1corneal staining was 66.70% in the OrthoK group and 56.70% in the DISC group, and the incidence of grade-2 corneal staining was 17.80% in the OrthoK group and 16.70% in the DISC group. In other words, the OrthoK group had slightly higher findings, but the difference was not significant ( P>0.05). The incidence of contact lens-associated papillary conjunctivitis was 2.20% in the OrthoK group and 10.00% in the DISC group, which was slightly higher than that in the orthokeratology lens group, but the difference was not significant( P>0.05). Conclusion: Both DISC lenses and OrthoK lenses can effectively control the increase in axial length in myopic children, and their have better effects than those of prescription glasses. The two tyes of contact lenses showed similar effects for controlling axial length increase. Both contact lenses have fewer corneal and conjunctival complications and better safety.

Investigation of retinal microvasculature and choriocapillaris in adolescent myopic patients with astigmatism undergoing orthokeratology.

BACKGROUND: To observe alterations of fundus microcirculation and retinal thickness in adolescent myopic patients with astigmatism after toric and spherical orthokeratology using optical coherence tomography angiography (OCTA), to explore the effects of orthokeratology on the retinal thickness and choroidal blood flow. METHODS: A total of 48 patients were enrolled and divided into two group (toric orthokeratology (T) group and spherical orthokeratology (S) group) according to the type of lens design. OCTA was used to measure the superficial and deep retinal vessel densities at the macular region, radial peripapillary capillary (RPC) density, foveal avascular zone (FAZ) area, and choriocapillaris (ChC) perfusion area before and after orthokeratology for 3 months. The data were statistically analyzed by SPSS 19.0 software. RESULTS: Compared with before orthokeratology, the superficial vessel density in the fovea and parafovea in the T group significantly increased, and the deep vessel density in the whole area and fovea were significantly elevated after 3 months (P < 0.05). The superficial vessel density was significantly higher only in the parafovea in the S group after 3 months than that before orthokeratology (P < 0.05), deep vessel density in the whole area and parafovea after 3 months was significantly higher than that before orthokeratology (P < 0.05). RPC density in the two groups increased after 3 months of orthokeratology in the whole area and inside the disc area (P < 0.05). Three months after toric orthokeratology, FAZ area in the T group was significantly reduced by 0.05 (- 0.41 to + 0.08) mm2, while ChC perfusion area was enlarged by 0.06 ± 0.12 mm2. FAZ area in the S group significantly decreased by 0.01 (- 0.19 to + 0.01) mm2, whereas ChC perfusion area increased by 0.06 (- 0.07 to + 0.50) mm2. Retinal thickness in the two groups increased after 3 months of orthokeratology in the whole area and parafoveal area (P < 0.05). CONCLUSION: Orthokeratology improved retinal blood flow in macular area and RPC while controlling myopia. The changes in FAZ and ChC perfusion areas did not significantly differ between toric and spherical orthokeratology.

[Analysis of Characteristic Eye Movement Behaviors of Young Adults with Different Degrees of Myopia].

Objective: To measure the parameters of eye movement of young adult patients of myopia, to compare the differences in the parameters of patient groups with varied degrees of myopia, and to analyze the correlation between eye movement parameters and axial length (AL) and spherical equivalent refraction (SER). Methods: A total of 91 young adult patients of myopia were recruited. The subjects were divided into three groups of low, moderate, and high myopia according to their SER. Information on the subjects' age and sex was collected and general clinical examination was completed. The subjects' binocular fixation, reflexive saccade, and antisaccade were measured with eye tracker. One-way ANOVA or Kruskal-wallis test was used to compare the general data and eye movement parameters of the three groups of myopic patients. Pearson or Spearman correlation analysis was used to analyze AL and SER's correlation with 95% bivariate contour ellipse area (BCEA) and saccadic parameters. Results: The 95% BCEA for mild, moderate, and high myopia groups were 2.08 (0.54, 14.69) deg 2, 4.99 (0.94, 49.22) deg 2, and 5.79 (2.18, 64.91) deg 2, respectively. There was significant difference between the 95% BCEA of the three groups ( P=0.029). The 95% BCEA of the mild myopia group was significantly smaller than that of the high myopia group ( P=0.01). There were no significant differences in saccadic parameters among the three groups ( P>0.05). There was a significant positive correlation between 95% BCEA and AL ( r=0.342, P=0.001). There was a significant negative correlation between 95% BCEA and SER ( r=-0.322, P=0.002). There was no significant correlation between the parameters of saccadic movement and the AL or SER ( P>0.05). Conclusion: For young adult myopic patients, the longer the AL is, the higher the degree of the myopia and the worse the fixation stability becomes. The fixation stability of patients with high myopia was significantly worse than that of patients with mild myopia. There was no significant difference in saccadic parameters in patients with different degrees of myopia.

A Meta-Analysis of Alterations in the Retina and Choroid in High Myopia Assessed by Optical Coherence Tomography Angiography.

BACKGROUND: High myopia (HM) is a risk factor for several pathological structural changes in retinal and choroidal thickness or vessel. To date, changes in retinal and choroidal microvasculature circulations in HM have yielded inconsistent results. OBJECTIVES: The objective of this article was to evaluate alterations in retinal and choroidal thickness, and capillary microvasculature using optical coherence tomography angiography (OCTA) in HM. METHODS: PubMed, Embase, and the Cochrane Library databases were searched for relevant published studies. Primary outcomes were foveal avascular zone, vessel density, retinal nerve fiber layer (RNFL) thickness, foveal thickness, sub-foveal choroidal thickness, and chorio-capillary density. Alterations in outcomes were evaluated by standardized mean difference with a 95% confidence interval. RESULTS: Eleven eligible articles were included for the meta-analysis. The whole superficial and deep vessel densities of macular and parapapillary superficial vessel density were lower in HM than in control eyes. The thickness of parafoveal RNFL, parapapillary RNFL, and sub-foveal choroid was significantly lower in HM eyes. Also, chorio-capillary density was shown to be lower in HM eyes. CONCLUSIONS: The retinal and choroidal vessel network change may be related to the axial elongation in the progression of myopia. Furthermore, OCTA is an effective and noninvasive technology for monitoring the progress of myopia eyes.

[Relationship between Myopia and Light Exposure].

Epidemiological studies found that the incidence of myopia was increasing year by year and the age of onset of myopia was showing a trend of affecting increasingly younger children. Reducing the occurrence of myopia and controlling the increase of myopia diopter have always been the focus of research on the prevention and control of myopia. Large randomized controlled clinical trials have found that outdoor activities can effectively reduce the incidence of myopia and delay the progression of myopia. Basic experiments also revealed that there were certain connections between light exposure and myopia. We herein review the research progress, limitations and future directions of research on light exposure and myopia. From the perspective of light properties, increasing the intensity of light can slow the progression of myopia and reduce the occurrence of experimentally induced myopia. However, the actual mechanism of action is still unclear. The rhythmic changes of light exposure caused by the light/dark cycle may cause abnormalities in the secretion of melatonin and dopamine, and changes in the circadian rhythm of intraocular pressure and choroidal thickness, thus affecting myopia. The red light, with relatively longer wavelength and forming images behind the retina, tends to induce myopia more easily, while the blue light, with medium and short wavelength and forming images before the retina, tends to delay myopia progression. However, different species respond differently to lights of different wavelengths, and the relationship between light wavelength and myopia needs further investigation. Future research can be done to further explore the mechanism of action of how light exposure changes the progression of myopia, including the following aspects: how light changes dopamine levels, causing changes in downstream signal pathways, and thus controlling the growth of the axial length of the eye; how retinal photoreceptor cells receive light signals of different wavelengths in order to adjust the refractive power of the eyes; and how to design artificial lighting of reasonable intensity, composition and properties, and apply the design in myopia prevention and control.

[Primary Diseases of 393 Cases of Pediatric Retinal Detachment and the Distribution of Clinical Characteristics].

OBJECTIVE: To investigate the primary diseases and the distribution of the clinical characteristics of pediatric retinal detachment. METHODS: Clinical records of patients aged 0-14 years old who had retinal detachment and who were hospitalized at the Department of Ophthalmology, West China Hospital, Sichuan University between January 2015 and December 2020, were retrospectively analyzed. The information on the demographic data, history, the scope of retinal detachment, and prognosis was retrieved and documented. RESULTS: A total of 464 eyes of 393 patients were included in this study, including 261 male and 132 female patients at a ratio of 1.98:1. The most common type of primary disease causing pediatric retinal detachments was associated with ocular dysplasia (227 cases, 57.8%), followed by trauma (78 cases, 19.8%) and myopia (56 cases, 14.2%). For infants and preschool children, the primary disease was predominantly ocular dysplasia at a rate of 81.8% (126 cases) and 55.8% (43 cases), respectively. For school-age children, in addition to ocular dysplasia (58 cases, 35.8%), myopia (49 cases, 30.2%) and ocular trauma (43 cases, 26.5%) also accounted for a large proportion of the primary diseases. The most common type of pediatric retinal detachment was rhegmatogenous retinal detachment (184 cases, 46.8%), and ocular trauma and myopia were the most common primary diseases, accounting for 37.5% (69/184) and 30.4% (56/184), respectively. 170 patients were diagnosed with traction retinal detachment, the second most common type of pediatric retinal detachment, and familial exudative vitreoretinopathy (FEVER) was the main primary disease, accounting for 47.6% (81/170). Exudative retinal detachment (39 cases, 9.9%) was the least common type of pediatric retinal detachment. Coats disease was the main primary disease causing exudative retinal detachment, accounting for 71.8% (28/39). After the first repair surgery, patients who had complete traction retinal detachment generally had poorer anatomical outcomes compared with those with complete rhegmatogenous retinal detachments (| Z|=3.026, P=0.002). The retinal break was most commonly seen on the temporal side in pediatric rhegmatogenous retinal detachments. In the retinal detachments caused by trauma, the most common type of retinal break was retinal tear, followed by ora serrata dialysis. Myopic rhegmatogenous retinal detachments were most commonly found in the round holes in lattice degeneration region. CONCLUSION: In the current study, boys were found to be more susceptible to retinal detachment than girls did. Ocular dysplasia, ocular trauma and myopia were major etiologic factors for pediatric retinal detachment. Appropriate information and education measures should be emphasized for different age groups.

[Prospective Study on Corneal Safety Evaluation of Children/Adolescents with Low and Moderate Myopia after Long-Term Orthokeratology].

OBJECTIVE: To observe the possible changes in the integrity of the cornea and corneal endothelial cells of children/adolescents with low or moderate myopia after long-term wearing of orthokeratology (ortho-k) lenses, as well as the time when the relevant changes occur, so as to evaluate the safety of long-term wearing of ortho-k lens and to provide a reference for the safety evaluation of subjects wearing ortho-k lenses. METHODS: Subjects were recruited in the Contact Lens Clinic, West China Hospital, Sichuan University for a three-year prospective study. Ortho-k of the same brand was matched for the subjects. The central corneal thickness (CCT), corneal endothelial cell density (ECD), and hexagonal cell ratio (HEX) were measured prior to the wearing of ortho-k lenses and after wearing ortho-k lenses for 1 month, 3 months, 6 months, and every 3 months until 36 months. The results of corneal fluorescence staining were recorded during each follow-up. When corneal staining was observed, the Efron grading standard was used for grading and corresponding treatment was given. RESULTS: A total of 33 (66 eyes) myopic patients were included in the study. 15 cases (46.2%) reported having binocular foreign body sensations and tearing within the first week of wearing the lenses. After the subjects became adapted to wearing the lenses, the symptoms disappeared without intervention. During the follow-up period, 31 cases (93.94%) of binocular corneal staining were observed, of which, 24 cases (72.73%) were graded as G0, receiving no treatment, 5 cases (15.15%) were graded as GⅠ, and 2 cases (6.06%) were graded as GⅡ. Corresponding clinical treatment for corneal staining was given to the GⅠ and GⅡ subjects. This study found that the corneal ECD was inversely proportional to age ( r=－0.380, P=0.002). During the three-year follow-up period, the subjects' left eye ECD decreased from the baseline at 24 months and the right eye ECD decreased from the baseline at 27 months ( P<0.05). The CCT results in the subjects showed that CCT became thinner at 1 month after wearing the lens ( P<0.05), but the follow-up CCT showed a stable trend. CONCLUSION: After three years of long-term follow-up, no serious corneal complications occurred in children/adolescents with moderate and low myopia after long-term wearing of ortho-k lens. The corneal ECD of both eyes started decreasing 24 months after wearing the ortho-k lenses and the CCT decreased 1 month after wearing the lenses.

[Significant Increase in Astigmatism after Cycloplegia in Two Children].

Two cases with high corneal astigmatism and mixed astigmatism were reported. Both cases showed significantly increased astigmatism after cycloplegia. Combined with the patients' refractive error, corneal topography and wavefront aberration changes, the possible causes were analyzed. Aberration changes caused by pupil dilation, corneal astigmatism differences in different diameter ranges, and changes in lens astigmatism before and after cycloplegia may lead to increased astigmatism after cycloplegia. It was found that cycloplegic refraction may not accurately reflect the refractive status in daily life for children with high corneal astigmatism, especially mixed astigmatism. Because children need refractive correction in the state of natural pupil, it is recommended that the cycloplegic refraction result could not be directly used as prescription for such children. The final prescription should be based on the topography and the refraction result under natural pupil.

[The Influence of Short-term Orthokeratology on Tear Film in Adult Myope].

OBJECTIVE: To study the changes of tear film after short-term overnight orthokeratology wearing in adult myope. METHODS: Fifty adult myope aged 18 to 38 years old were enrolled in this study. The patients wore orthokeratology 6-10 h every night during this study. Data such as non-invasive tear break-up time (NITBUT), fluorescent tear break-up time (FTBUT), lower tear meniscus height (LTMH), corneal fluorescent staining as well as ocular surface disease index (OSDI) questionnaire score were measured at baseline, 1 d, 7 d, 14 d, 30 d and 90 d. RESULTS: Forty-four subjects completed the follow-up study. Tear break-up time (TBUT) decreased and became stable at 14 d after overnight orthokeratology wearing. LTMH sustained decreased and there was a difference after 90 d overnight wearing （ P<0.05）. Compared with baseline, the grade of corneal staining increased at all time points （ P<0.05）. As for the OSDI score, there was no difference at all time points. CONCLUSION: After overnight orthokeratology wearing, tear film stability and tear secretion decreased. Adult myope seems easily to suffer corneal injury after overnight orthokeratology wearing.

[Motion-in-depth Perception and Static Stereopsis of Patients with Strabismics].

OBJECTIVE: To determine the role of motion-in-depth perception and static stereopsis in strabismics, and factors associated with the perception of motion-in-depth. METHODS: A total of 84 strabismic patients (including 57 intermittent exotropes, 12 constant exotropes and 15 esotropes) and 16 normal controls were recruited. Binocular fusion ability, static stereopsis and motion-in-depth perception were tested using the computer-generated stereoscopic stimuli. The correlations between these tests were analyzed. RESULTS: There was a significant correlation between motion-in-depth perception and static stereopsis in strabismics. Only patients with static stereopsis demonstrated the perception of motion-in-depth. A positive correlation was found between motion-in-depth perception thresholds and static stereopsis in intermittent exotropes. All participants in the control group had motion-in-depth perception and static stereopsis. The participants with stereopsis had significantly lower thresholds than those with strabismus (P<0.01). The perception of motion-in-depth varied with the type of strabismus: 87.7% of the intermittent exotropes exhibited motion-in-depth perception, whereas none of the constant strabismics were able to pass the motion-in-depth perception tests. The perception of motion-in-depth was correlated with the presence of binocular fusion. CONCLUSIONS: Motion-in-depth perception is correlated with static stereopsis in strabismics. The perception of motion-in-depth varies with the type of strabismus: only intermittent exotropes have the perception of motion-in-depth.

[Efficacy of Superior Rectus and Lateral Rectus Muscle Belly Union Surgery for Myopic Strabismus Fixus].

OBJECTIVE: To evaluate the effectiveness of superior rectus (SR) and lateral rectus (LR) union suture without scleral fixation for the treatment of myopic strabismus fixus. METHODS: A retrospective review was performed on 27 eyes of 16 patients who underwent lateral part of SR and superior part of LR muscle belly union between January 2010 and October 2015. We collected the ocular data including: best corrected visual acuity,axial length,CT or MRI images,orthoptic measurements (by prism test),and eye movements pre- and postoperatively. RESULTS: The follow up time varied from 3-12 months. All of the patients got satisfactory results except two severe cases. A statistical change of prism test value and eye movement was noticed ( P<0.01). Orthoptic measurements showed that the mean esotropia was improved from (92.50±18.17)Δ preoperatively to (9.19±4.39)Δ postoperatively ( P<0.01). In regards for the vertical deviation,the mean residual hypotropia was (2.38±3.10)Δ postoperatively compared to (21.88±5.74)Δ preoperatively ( P<0.01). At the last follow-up,mean abduction limitation was improved from -3.19±0.62 to -1.15±0.52 ( P<0.01),mean elevation limitation was improved from -2.85±0.82 to -0.78±0.51 ( P<0.01). No special complications were noted. CONCLUSION: Muscle belly suture of SR and LR was an effective surgery to correct ocluar misalignment and motility in myopic strabismus fixus.

[Visual performance of amblyopia before and after correcting higher order aberrations with adaptive optics system].

OBJECTIVE: To investigate visual performance of monocular amblyopia before and after correcting higher order aberrations (HOAs) with adaptive optics system. METHODS: Visual acuity (VA) and contrast sensitivity (CS) thresholds of ten monocular amblyopes were measured before and after correcting higher order aberrations with adaptive optics system. The change of them were analyzed. RESULTS: A significant improvement of 0.16 times on average (P = 0.005) visual acuity of the amblyopic eyes and 0.34 times on average (P < 0.001) CS thresholds, mainly improved at 24 cpd were observed. CONCLUSION: The visual performance of amblyopic eyes can be improved after correcting higher order aberrations, and HOAs affect CS at some high spatial frequency.

[Ocular higher-order aberrations in patients with neovascular age-related macular degeneration].

OBJECTIVE: To evaluate changes in higher-order aberrations of eyes in patients with unilateral neovascular age-related macular degeneration (nAMD). METHODS: Thirty two patients with unilateral nAMD were recruited for this study. Biocular higher-order wavefront aberrations for a 6-mm pupil were measured with Zywave II aberrometer (Bausch & Lomb, Zyoptix, USA). The root mean square (RMS) of Zernike coefficients were compared between the eyes with nAMD and the fellow eyes. Relation ship between RMS values and LogMAR vision of the nAMD were analysed. RESULTS: The total higher-order aberrations (HOAs), third order aberrations (RMS3), sphere aberration (SA), coma, coma along x axis, and horizontal trefoil in the eyes with nAMD were all significantly greater than those in the fellow eyes (P < 0.05). Increases of vertical trefoil and coma were found to be associated with increased LogMAR values (r(s) = 0.377, P = 0.034; r(s) = 0.416, P = 0.018). CONCLUSION: Higher-order aberrations in nAMD are greater than normal eyes, which may have effects on distant corrected visual acuity. Examinations of higher-order aberrations should be added into visual function evaluations of nAMD.

[The relationship between refractive error and influencing factors in children].

OBJECTIVE: To investigate the influence of refractive factors, including axial length, cornea power and astigmatism, and total astigmatism to refractive errors. METHODS: Axial length (AL) and cornea power (K) of 295 children (590 eyes) aged 8. 43 years old (4-14 years old) were obtained through IOL-Master, refractive error was measured by retinoscope after cycloplegia. The eyes were divided into 7 groups according to their spherical equivalence (SE). The 7 groups were high myopia, moderate myopia, low myopia, emmetropia, low hyperopia, moderate hyperopia and high hyperopia. AL and cornea parameters of different groups were compared using ANOVA and Pearson's correlation was used to analyze the relationship between SE, AL and cornea astigmatism and total astigmatism respectively. RESULTS: (1) Of the 7 groups, AL was longest in the high myopia group and shortest in the high hyperopia group. There was a statistically significant difference (P < 0.05) in AL among the 7 groups. (2) High and moderate myopes had the greatest K values and though there was no difference between the 2 groups, they had greater K values compared to other groups (P < 0.05). Moderate hyperopes had the smallest K values which were smaller than any other group except high hyperopia group. (3) SE was negatively correlated with K (r = -0.242, P < 0.001) and positively correlated with cornea astigmatism (r = 0.131, P = 0.001) but had no correlation with total astigmatism. AL was negatively correlated with cornea astigmatism (r = -0.218, P < 0.001) and had no correlation with K and total astigmatism. (4) Multiple linear regression using AL, K and age as independent variable and SE as dependent variable was applied to analyze the relationship of these variables, and the equation was. CONCLUSION: The bigger the cornea K value and the longer the AL were, the more myopia the eye was. The study showed that cornea K value of high hyperopes became steeper, indicating that the corneas of high hyperopes tried to compensate for the hyperopic refractive error due to short AL so that the eye can grow toward emmetropization; but the corneas of other groups had the same trend as the AL, which caused myopia or hyperopia together. However, generally speaking, the cornea became steeper as myopia got more severe and flatter as hyperopia more severe.

[Retinal nerve fiber layer and macular thickness in the fellow eyes of patients with anisometropic amblyopia].

OBJECTIVE: To measure the retinal structure of the fellow eyes of patients with anisometropic amblyopes with retinal nerve fiber layer thickness (RNFLT), macular thickness (MT), and their correlations with axial length (AL) and spherical equivalent (SE). METHODS: AL was measured by IOLMaster. RNFLT and MT were obtained through optical coherence tomography (OCT). The data of the 56 unilateral amblyopes (56 fellow eyes) were compared with those of 170 normal eyes from 85 age-matched people. RESULTS: The fellow eyes had thicker RNFLT (RNFLT-fc), temporal RNFLT (RNFLT-t) and inferior (RNFLT-i); and thinner nasal RNFLT (RNFLT-n) than the normal eyes. But no statistically significant differences in superior RNFLT (RNFLT-s) and MT were found between the fellow eyes and normal eyes. After adjustments for age, gender and AL or SE, only the change of RNFLT-t remained significant (P < 0.05 ). Partial correlation analysis between the thickness values and AL/SE adjusted for age and gender showed different trends between the fellow eyes and normal eyes. Multiple linear regression adjusted for age and gender also obtained different coefficients between the fellow eyes and normal eyes. Independent sample t test found no difference in thickness parameters between occlusion and non-occlusion eyes in patients with anisometropic amblyopes. CONCLUSION: Fellow eyes of patients with anisometropic amblyopes have subnormal retinal structure despite a normal corrected visual acuity. Occlusion does not affect the retinal structure. AL or SE can affect the measurements of RNFLT.

Features and changes in retinal nerve fiber layer thickness in high myopic ocular hypertension: a 1-year prospective follow-up.

PURPOSE: To observe the features and changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in highly myopic ocular hypertension (HM-OHT) patients. STUDY DESIGN: Prospective observation study. METHODS: Individuals who met the inclusion criteria were recruited into three groups: the healthy high myopia (HM), non-highly myopic ocular hypertension (OHT) and HM-OHT group. The spherical equivalent refraction, axial length, intraocular pressure, central corneal thickness and pRNFL thickness were collected and compared between groups. The OHT and HM-OHT group were followed up for 12 months. The changes in pRNFL thickness across the follow-up times were analyzed. RESULTS: The study included 92 subjects. The mean pRNFL thicknesses were 102.5 ± 11.1 µm in the HM (31 people), 101.9 ± 11.7 µm in the OHT (34 people) and 102.2 ± 12.0 µm in the HM-OHT group (27 people). There was no statistical difference in the mean pRNFL thickness among the three groups. The HM-HOT group and HM group had thicker temporal sectoral (p < 0.05) pRNFL thickness and thinner superior sectoral (p = 0.015) pRNFL thickness than the OHT group. During the 12-month follow-up, the mean pRNFL thickness of the HM OHT group decreased, with an annual reduction of -0.93 ± 0.14 µm. There was a significant difference across the three visits (p < 0.05), while there were no significant differences in the OHT group (p = 0.591). CONCLUSIONS: After ocular magnification correction, the HM-OHT group did not have thinner pRNFL thickness than the other two groups. However, the thickness decreased significantly over time.

[Characterize the differences between anisometropic amblyopes and normal people when discriminating different pictures under various degrees of Gauss noises].

OBJECTIVE: To observe the differences between anisometropic amblyopes and normal people when all of them were asked to discriminate those topological and non-topological pictures embedded in Gauss noises. METHODS: Stimulus pictures (noise variance were 0.04, 0.08, 0.12 respectively) were run using Matlab software, the error ratios of identification of amblyopia groups and control groups were recorded. RESULTS: The P-values of anisometropic amblyopes were 0.06 (closure pictures) and 0.088 (disclosure pictures) under the different experimental lasting time. No matter whenever the experimental lasting time and whatever the characteristics of the pictures, the error ratios of identification of amblyopia groups were higher than that of control groups, except for closure pictures at 5 s. CONCLUSION: The capabilities of amblyopes when discriminate the different pictures were lower than that of normal groups. We found that different outcomes of amblyopia groups were caused by their own perception defect.

The Effect of A2E on the Uptake and Release of Calcium in the Lysosomes and Mitochondria of Human RPE Cells Exposed to Blue Light.

We aimed to explore the effect of N-retinylidene-N-retinylethanolamine (A2E) on the uptake and release of calcium in lysosomes and mitochondria by establishing a model of human retinal pigment epithelial (RPE) cell injury induced by exposure to blue light. Primary human RPE cells were cultured from passages 4 to 6 and exposed to blue light at an intensity of 2000 ± 500 lux for 6 hours. After blue light exposure, the culture was maintained for 24 hours. A2E at a final concentration of 25 µM was added to the culture 2 hours before light exposure, and nifedipine at a final concentration of 10-4 M was added 1 hour before light exposure. The levels of Ca2+ in the cytosol (CaTM/2AM), mitochondria (Rhod/2AM), and lysosomes (LysoTracker Red and Fluo-3/AM) were determined. In order to measure the calcium levels in the different organelles, RPE were imaged using a laser scanning confocal microscope. Moreover, changes in the mitochondrial membrane potential were detected by flow cytometry analysis of JC-1-stained cells. The obtained results revealed that blue light illumination increased the calcium fluorescence intensity in the cytoplasm, mitochondria, and lysosomes of human RPE cells when compared with the control cells (P < 0.05). After A2E treatment, the fluorescence intensity of the calcium in the cytoplasm was further increased (P < 0.05), while that in the mitochondria and lysosomes decreased (P < 0.05). In addition, we observed that nifedipine reduced the fluorescence intensity of calcium in the RPE cells. Our results also showed that the mitochondrial membrane potential in the RPE treated with blue light and A2E was lower than that in the control, blue light, and A2E-treated cells (P < 0.05). Blue light increased calcium levels in the cytoplasm, lysosomes, and mitochondria of RPE cells. A2E damages the lysosomal and mitochondrial membranes, resulting in calcium release into the cytoplasm. Finally, our results demonstrated that both blue light and A2E treatments reduced mitochondrial membrane potential, increasing cytosolic Ca2+ levels, which can contribute to the activation of RPE death.

[Contrast sensitivities of the fellow eyes in children with anisometropic and strabismic amblyopia].

OBJECTIVE: To investigate the contrast sensitivities of the fellow eyes in children with anisometropic and strabismic amblyopia. METHODS: A retrospective study was undertaken. Medical records containing contrast sensitivity data of the fellow eyes in 107 children with anisometropic amblyopia, 110 children with strabismic amblyopia, and 30 normal children were retrieved. The contrast sensitivities of the fellow eyes in those children were compared using independent t-test and one-way analysis of variance (ANOVA) with post hoc (modified LSD) multiple comparison test. RESULTS: Contrast sensitivity functions of the fellow eyes of children with anisometropic and strabismic amblyopia were weaker than those of the controls. The fellow eyes of children with moderate and severe strabismic amblyopia had better contrast sensitivities than those with anisometropic amblyopes. In strabismic amblyopic children, the contrast sensitivities of the fellow eyes grew with the degree of amblyopia. Occlusion therapy did not change contrast sensitivities of the fellow eyes. CONCLUSION: The abnormal intraocular interactions between amblyopic and nonamblyopic "normal" eyes decrease the contrast sensitivity functions of the fellow eyes. Compared with anisometropic amblyopic children, the fellow eyes of children with moderate and severe strabismic amblyopia show more superiority in the binocular competition. Occlusion therapy may not depress contrast sensitivities of the fellow eyes in children with amblyopia.