Low Myopia Group Research Articles

Evaluation of Retinal Nerve Fiber Layer, Ganglion Cell-Inner Plexiform Layer, and Optic Nerve Head in Glaucoma Suspects With Varying Myopia.

Myopic glaucoma suspects, particularly with high myopia, experience thinning of nontemporal parameters of retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL), without change in optic nerve head (ONH) parameters. The aim was to assess the effect of myopia on RNFL, GCIPL, and ONH parameters in glaucoma suspects. Seventy-six eyes of glaucoma suspects studied with Cirrus high definition optical coherence tomography were divided into low (n=27), moderate (n=25), and high myopia (n=24) groups. Optical coherence tomography parameters were correlated with spherical equivalent (SE) and evaluated with areas under the receiver operating characteristic curve for quantifying diagnostic ability to differentiate high myopia from nonhigh myopia. In high myopia, SE was positively correlated with thinning of average, minimum, and nontemporal GCIPL and thinning of average and nontemporal RNFL (P<0.05 for all), but not for inferior RNFL (P=0.28). In moderate myopia, SE was correlated with thinning of inferonasal and minimum GCIPL as well as superior and inferior RNFL (P<0.05 for all). SE was not correlated with ONH parameters in moderate or high myopia (P>0.05). The largest areas under the receiver operating characteristic curve for RNFL and GCIPL parameters were for superior (0.82) and superonasal (0.80) regions, respectively, with comparable diagnostic ability (P=0.74). High myopia, in particular, is associated with thinning of average RNFL, average and minimum GCIPL, and nontemporal parameters of both RNFL and GCIPL, warranting consideration of refractive status in glaucoma suspects.

Comparison of the Clinical Efficacies of 0.01% Atropine and Orthokeratology in Controlling the Progression of Myopia in Children

ABSTRACT Purpose : To compare the clinical efficacies of 0.01% atropine and orthokeratology (OK) in slowing the development of myopia, and to evaluate their effects on basal tear secretion and tear film stability. Methods : A prospectively, randomised study. A total of 120 children aged 8–14 years with myopia were included; of these, 60 participants were randomly assigned to use spectacles and 0.01% atropine (SA) and the remaining 60 wore OK lenses (OK). Comprehensive ophthalmologic examinations were performed before and after treatment every 3 months. Results : The primary outcomes include the changes of spherical equivalent refraction (SE) and axial length (AL). After one-year, the SE and AL in participants aged ≤10 years were better controlled in the SA in low-myopia group (P < .05), whereas those aged ≥11 years were better controlled in the OK in high-myopia group (P < .05). Secondary outcomes include Schirmer’s test and tear film break-up time (TBuT). A statistically significant difference was found in TBuT between the SA and OK in the first 3 months and there was a statistically significant difference in TBuT in the OK between before and after 3 months; however, no statistically significant difference was observed after 6 months. Conclusion : Both 0.01% atropine and OK lenses effectively retarded myopia progression; however, different effects were found in different ages and refractions. 0.01% atropine had no evident effect on Schirmer’s test and TBuT results. Furthermore, OK lenses had no effect on Schirmer’s test, whereas it had a significant effect on TBuT after only the first 3 months.

Changes of retinal thickness in macular area of myopia children

Objective: To study the changes of macular retinal thickness in children with moderate and low myopia by frequency domain OCT. Methods: 108 school-age children aged 7-12 years were selected and enrolled into the group. Among them, 58 cases (116 eyes) with simple moderate and low myopia in the myopia group and 50 cases (100 eyes) with straight eyes in the emmetropia group. The retinal thickness in different parts of macular area was compared between the two groups, and the correlation between retinal thickness in different parts of macular area and diopter and axial length was analyzed by Pearson correlation analysis. Results: The length of eye axis in moderate and low myopia group was longer than that in emmetropia group, and the difference was statistically significant (P &lt; 0.05). There was no significant difference in CMT(Central Macular Thickness) and I-AMT(average macular thickness of inner circle) between the two groups (P &gt; 0.05). The AMT(Average Macular Thickness) and O-AMT(average macular thickness of outer circle) in moderate and low myopia group were lower than those in emmetropia group, and the differences were all statistically significant (P &lt; 0.05). The thickness of the retina below the macula and the nasal side was positively correlated with the refractive power in patients with moderate to low-grade myopia (r=0.201, 0.302, P＜0.05), and the thickness of the retina around the macula was negatively correlated with the refractive power (r=-0.326, P＜0.05). Conclusion: There is no significant difference in macular central retinal thickness between children with moderate and low myopia and normal children, and the thickness of paracentral retina tends to become thinner with the deepening of myopia.

Effect of myopia and optic disc area on ganglion cell-inner plexiform layer and retinal nerve fiber layer thickness.

Purpose:The aim of this work was to study the impact of myopia and different optic disc areas on ganglion cell-inner plexiform layer (GCIPL) and retinal nerve fiber layer (RNFL) thickness profiles in myopic patients by spectral-domain optical coherence tomography (SD-OCT).Methods:This was a cross-sectional study of 100 eyes of 50 myopic individuals. All patients underwent complete ophthalmic evaluation and SD-OCT examination. According to spherical equivalent (SE), patients were divided into M1, M2, and M3 (low, moderate, and high myopia group). According to optic disc area values, patients were divided into D1, D2 and D3 (small, medium and large disc groups). Average GCIPL and RNFL thickness recorded globally and separately for all quadrants and also according to 12 clock hours and analyzed with respect to different myopic groups, optic disc area groups, and axial length.Results:Quadrantic RNFL thickness profiles and their average RNFL thickness were significantly thinner in high myopic group compared to low myopic group, except for the temporal quadrant (P < 0.05). Average RNFL and RNFL thickness of all quadrants were significantly thicker in the large disc group than in the small disc group (P < 0.05). Average GCIPL and GCIPL thicknesses of all sectors were significantly thinner in high myopic group compared to low myopic group (P < 0.05). No significant correlation was observed between GCIPL and disc area changes. Average RNFL thickness correlated significantly with SE (3.667 μm/diopter), axial length (–5.3805 μm/mm) and optic disc area (9.4617 μm/mm2). Also, average GCIPL thickness correlated statistically significantly with SE (1.6807 μm/diopter) and axial length (–2.626 μm/mm).Conclusion:Myopia and axial length significantly reduce RNFL and GCIPL thickness profiles but the optic disc area significantly increases RNFL thickness, but not GCIPL thickness.

Comparison of clinical outcomes after femtosecond laser in situ keratomileusis in eyes with low or high myopia.

To compare the clinical results of femtosecond (FS) laser in situ keratomileusis (LASIK) in high myopic patients and low myopic patients. This study included 212 myopic eyes undergoing LASIK using a VisuMax 500kHz FS laser. All treated eyes were assigned to one of two groups according to preoperative manifest spherical refraction: low myopia group (A, >-4.0 D) and high myopia group (B, ≤-4.0 D). Uncorrected and corrected distance visual acuity (UDVA, CDVA), refractive errors, and higher-order aberrations (HOAs) were measured preoperatively and 1wk, 1, 3 and 6mo postoperatively. At 6mo of follow-up, 92% and 76% had a UDVA of 20/20 or better in group A and B, respectively (P=0.037) and UDVA was significantly different between two groups (P=0.042). Six and seven percentage lost one line of CDVA in group A and B, respectively (P=0.572) and no eyes in both groups lost more than two lines. Each group had 87% and 76% of treated eyes within ±0.5 D of the intended correction (P=0.186), and 13% and 43% with a change of >0.50 D in spherical equivalent from 1wk to 6mo postoperatively (P=0.005). In terms of postoperative astigmatism, each group had 89.1% and 76.6% within ±0.50 D, respectively and there was significant difference (P=0.006). Group A tends to induce smaller HOAs than group B. FS LASIK is effective and safe for correcting high myopia as well as low myopia. However, high myopic eyes showed more postoperative astigmatism and HOAs which affect visual acuity.

A longitudinal study of the effect of ocular biometrics measures on myopia onset.

To investigate the relationship between ocular biometrics (OB) and myopia onset. OB data from students in 4 grades (aged from 6 to 14 years) in China were collected in a 1.5-year longitudinal study. Refractive error was assessed with cycloplegic autorefraction. At baseline, 934 (56.33%) of the subjects (right eye) had myopia. The mean spherical equivalent (SE) and axial length to corneal radius (AL/CR) were - 2.14 ± 1.49 and 3.14 ± 0.11, respectively, in the subjects with myopia and - 0.09 ± 0.21 and 2.98 ± 0.07, respectively, in the subjects without myopia. The correlation between the SE and AL/CR was r = - 0.823 (P < 0.001). The slopes of the SE changing with the AL/CR (and R-squares) were - 0.28 to - 1.80 (0.01-0.14) in the no myopia group, - 3.40 to - 6.20 (0.20-0.48) in the low myopia group, and - 3.37 to - 11.34 (0.16-0.74) in the moderate and high myopia groups. The baseline AL/CR values in grades 1, 3, and 5 were higher in those who developed myopia within 1.5 years. The odds ratio of the AL/CR to myopia onset in 1.5 years was 1.096 (95% confidence interval (CI): 1.060-1.135). Of the five indicators, the AL/CR showed the best correlation with the SE. The adjoint and linear relationship between the AL/CR and the SE tended to increase with SE progression. When myopia progressed beyond a certain range, the AL/CR was significantly different in those without initial myopia who developed it within 1.5 years compared with those who did not. After adjusting for age, sex, school, and grade, the interpretation capability of the current AL/CR to myopia onset in 1.5 years was limited.

Clinical results of orthokeratology therapy in adolescents with low to moderate myopia.

To observe the clinical results of orthokeratology therapy in adolescents with low to moderate myopia after wearing the lens for 6 months. The data of 69 adolescents with low to moderate myopia were retrospectively analyzed. According to the degree of spherical power before treatment, the adolescents were divided into a low myopia group (34 cases, with spherical diopter from -3.00 to -0.75 D) and a moderate myopia group (35 cases, with spherical diopter from -5.75 to -3.25 D). The changes of the uncorrected distance visual acuity (UDVA), intraocular pressure, count of endothelial cell, eye axis length, Strehl ratio (SR), modulation transfer function (MTF), Q value, and wavefront aberrations before the treatment and 6 months after the treatment were compared and analyzed between the 2 groups. Compared with before the treatment, the UDVA improved significantly in the 2 groups (both P<0.05); the intraocular pressure and the count of endothelial cell did not change obviously in the 2 groups (all P>0.05), the eye axial length in the 2 groups was increased significantly (both P<0.05), but there was no significant difference between the 2 groups (all P>0.05); the Q value in the 2 groups was increased significantly, and the change was more obvious for the moderate myopia group (all P<0.05); the SR and MTF were increased remarkably in the 2 groups (all P<0.05), and there were no significant difference in the changes of SR and MTF between the 2 groups (both P>0.05); a considerable decrement was found for the total aberration, the total low-order aberration, and defocus (all P<0.05), and the changes were more significant in the moderate myopia group (all P<0.05); the total high-order aberrations were increased in the low myopia group (P<0.05); the increment of the vertical astigmatism, spherical aberration, horizontal coma, vertical coma, and horizontal trefoil were noticeable (all P<0.05), and the changes of the spherical aberration, vertical coma, and horizontal trefoil were more obvious in the moderate myopia group (all P<0.05). Orthokeratology can effectively improve the visual results of the adolescents with low to moderate myopia, and the corrective effect is more obvious for the adolescents with moderate myopia than those with low myopia.

Quantitative Analysis of Human Corneal Lenticule Surface Microstructure Irregularity with 3D Optical Profiler Using White Light Interferometry

ABSTRACT Purpose To quantitatively evaluate the cutting quality of small incision lenticule extraction (SMILE) by measuring human corneal lenticule surface roughness in different areas with white light interferometer. Method A white light interferometer was used to quantitatively measure the corneal lenticule surface roughness in different areas. Sixty-three myopic patients (102 eyes) who underwent SMILE surgery were recruited. The surface roughness of the central, pericentral, and peripheral parts of the corneal lenticule surface was measured in both the anterior and posterior planes. Differences in corneal lenticule surface roughness were analyzed between different myopic groups. Results The surface roughness of the anterior plane of the corneal lenticule was lower than the posterior plane in various areas (central, pericentral, and peripheral parts) (P < .01). Surface roughness gradually increased from the center to the periphery, in both the anterior and posterior planes (P < .01). There were no significant differences in the surface roughness of the central part in both the anterior and posterior planes between the low and high myopic groups. The surface roughness of the high myopic group was higher than that of the low myopic group in the peripheral part (P < .01). There were no significant differences among the three cylinder-specific groups. There was no significant correlation between two paired eyes. A positive correlation between posterior central surface roughness and the percentage tissue altered score (PTA) was found (r = 0.248, P = .012). Conclusions The cutting surface of the corneal lenticule performed by femtosecond laser was evaluated with a white light interferometer and displayed inhomogeneity. Deeper cutting with higher myopia and some intraoperative complications, such as suction loss, may result in larger irregularities.

Comparative characteristics of the functional state of the Autonomous and Central nervous systems depending on the presence and degree of myopia in students

Introduction. In children and adolescents myopia in some countries already reached epidemic levels due to the growing prevalence is an urgent need for new approaches to management and search for screening indics of its development risk and key points in its stabilization. Taking into account the development and progression of myopia may be associated with autonomous influences of the nervous system, it becomes relevant to study the features of the autonomous status formation in children, depending on the presence and degree of myopia. Material and methods. The functional state of the autonomic nervous system in 380 5-10 grades students with low degree myopia (group 1), moderate myopia (group 2), and without myopia (group 3) was assessed by heart rate and central nervous system variability and mental performance using variation chronoreflexometry. Results. The maximum number (40%) was recorded in eighth grade of myopia students, 39.4% cases - in fifth grade students. An imbalance in the autonomic nervous system in schoolchildren was established to increase with growing myopic refraction. Thus, vagotonia occurred in 42.8% of students with low degree myopia, eutonia - in 42%, and sympathicotonia only in 15.2%. While in students with moderate myopia in 75% of cases the constraint of regulation systems was revealed due to excessive tone of the sympathetic part of the autonomic nervous system, which leads to uneconomic work of the cardiovascular system and a sharp decrease in the functional reserves of the body in 50% -70% of students. Conclusion. Consideration of the relationship of myopia with the autonomous status and functional state of the central nervous system offers new directions to the existing concepts of myopia management in children and adolescents of school age, which can be a starting point for solving the problem of prevention of myopia and its progression.

Comparative characteristics of the functional state of the Autonomous and Central nervous systems depending on the presence and degree of myopia in students

Introduction. In children and adolescents myopia in some countries already reached epidemic levels due to the growing prevalence is an urgent need for new approaches to management and search for screening indics of its development risk and key points in its stabilization. Taking into account the development and progression of myopia may be associated with autonomous influences of the nervous system, it becomes relevant to study the features of the autonomous status formation in children, depending on the presence and degree of myopia. Material and methods. The functional state of the autonomic nervous system in 380 5-10 grades students with low degree myopia (group 1), moderate myopia (group 2), and without myopia (group 3) was assessed by heart rate and central nervous system variability and mental performance using variation chronoreflexometry. Results. The maximum number (40%) was recorded in eighth grade of myopia students, 39.4% cases - in fifth grade students. An imbalance in the autonomic nervous system in schoolchildren was established to increase with growing myopic refraction. Thus, vagotonia occurred in 42.8% of students with low degree myopia, eutonia - in 42%, and sympathicotonia only in 15.2%. While in students with moderate myopia in 75% of cases the constraint of regulation systems was revealed due to excessive tone of the sympathetic part of the autonomic nervous system, which leads to uneconomic work of the cardiovascular system and a sharp decrease in the functional reserves of the body in 50% -70% of students. Conclusion. Consideration of the relationship of myopia with the autonomous status and functional state of the central nervous system offers new directions to the existing concepts of myopia management in children and adolescents of school age, which can be a starting point for solving the problem of prevention of myopia and its progression.

A quality of life assessment of military recruits after refractive surgery

AIM: To evaluate the quality of life of recruits after refractive surgery. METHODS: Population-based, cross-sectional study. Using the Quality of Life Impact of Refractive Correction (QIRC) questionnaire, the quality of life in 615 recruits underwent refractive surgery was evaluated. The overall score and each question score of QIRC were compared between subgroups of different strength of preoperative refractive error, postoperative interval, type of surgical procedure and postoperative recovery. RESULTS: The mean overall QIRC score of recruits underwent refractive surgery was 49.15±7.89. Significant difference was found for strength of preoperative refractive error (F=4.16, P&lt;0.05), with the low myopia group (50.67±7.59) had significantly better scores than those with high myopia (47.57±7.52, F=4.16, P&lt;0.05). Recruits after a postoperative interval no more than 6mo (49.18±7.86) scored equally to those of more than 6mo (49.18±8.03). Recruits underwent surface ablation surgery scored lowest (46.68±6.09), but showed no significant difference when compared with all underwent refractive surgery (t=1.99, P&gt;0.05). Scores of recruits underwent mechanical microkeratome laser in situ keratomileusis (MK-LASIK), Sub-Bowman’s keratomileusis (SBK), femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK), femtosecond lenticule extraction (ReLEx flex) or small-incision lenticule extraction (ReLEx SMILE) procedure showed no significant difference too. Recruits had adverse complaints postoperatively (45.85±6.66) scored lower when compared with all underwent refractive surgery (t=5.28, P&lt;0.01). CONCLUSION: The quality of life of recruits after refractive surgery was good except those with postoperative complications. Preoperative low myopia recruits had better quality of life than medium and high myopia ones.

A comparative study of OCT findings in low and high myopia

Aim This study aimed to compare macular findings between low and high myopia. Patients and methods In all, 60 myopic eyes were included in this study. They were divided according to refraction into low myopia of less than or equal −6 SD and high myopia of more than −6 SD. All patients were subjected to automated refraction, correction of vision, A-scan by Isa intra Ocular length (IOL) master for axial length, and optical coherence tomography (OCT) scan for macular mapping. Results The mean central macular thickness (CMT) of low myopic cases was 255.5±17.13, with all low myopic cases showing no complication by OCT while the mean CMT of high myopia was 262.10±67.51 with some complications. Regarding choroidal neovascularization (CNV), it was statistically significantly higher in the high myopic group when compared with the low myopic group, while macular hole showed no significance. Thinning of RPE and myopic contour showed high significant statistical difference to high myopic group. Discussion The mean CMT of low myopic cases was slightly thinner than in high myopic cases but with no statistical significance. Myopic CNV is more common with high myopia and may be related to sex. Thinning of RPE and myopic contour are mainly found in high myopia. Conclusions In our study, there was no significant correlation between CMT and axial length. Regarding CNV, it was statistically significantly higher in the high myopic group when compared with the low myopic group, while macular hole showed no significance. Thinning of RPE and myopic contour are mainly found in high myopia.

Comparison of Corrected Intraocular Pressure Methods after Corneal Refractive Surgery according to Corneal Ablation Amounts

Purpose : The purpose of this study was to evaluate the intraocular pressure (IOP) that would be underestimated after corneal refractive surgery according to corneal ablation amounts, and was to suggest the most appropriate corrected IOP method for each group. Methods : The subjects were 1,002 eyes of 501 people (237 men, 264 women) who underwent corneal refractive surgery. The mean age was 26.89±5.18 years. IOP was measured with a non-contact tonometer and 4 correction methods, and was used to correct the underestimated IOP. IOP in three groups with low, moderate and high myopia according to ablation amounts was analyzed postoperative corrected IOP to compare correction methods. Results : The preoperative IOP was 15.67±2.39 mmHg and postoperative IOP was 10.12±2.11 mmHg, which was significantly lower than the mean 5.55±2.09 mmHg. The postoperative IOP calculated by Ehlers' correction method was 14.53±2.47 mmHg, which was 1.14±2.83 mmHg different from the preoperative IOP, showing the most similar to preoperative IOP. In addition, the IOP corrected by the Ehlers equation showed the smallest difference from preoperative IOP in all groups. Conclusion : The Ehlers correction method is shown the most accurate among the four correction methods in low, moderate, and high myopia groups after corneal refractive surgery. It would be a useful method for preventing the late diagnosis and treatment of glaucoma.

SMILE With Low Energy Levels: Assessment of Early Visual and Optical Quality Recovery

To assess early visual and optical quality recovery according to preoperative refraction after small incision lenticule extraction (SMILE) at low energy level for myopia and myopic astigmatism treatment. This prospective study included 101 eyes of 101 patients separated into three groups: low myopia (30 eyes), with a mean spherical equivalent (SE) of -2.13 ± 0.73 diopters (D); moderate myopia (33 eyes), with a mean SE of -4.53 ± 0.86 D; and high myopia (38 eyes), with a mean SE of -6.54 ± 0.78 D. Visual acuity, contrast sensitivity, refraction, corneal higher order aberrations, modulation transfer function, Strehl ratio, and Objective Scatter Index (OSI) were measured. All eyes had a corrected distance visual acuity of 20/20 or better at 1 day in the low myopia group and 1 month in the moderate and high myopia groups. The contrast sensitivity preoperative values recovered at 8 days in the low myopia group and 1 month in the moderate and high myopia groups. At 1 month, the low myopia group recovered the OSI preoperative values (0.61 to 0.69) and the OSI values were slightly higher than the preoperative value in the moderate and high myopia groups (0.74 to 1.00 and 0.8 to 1.14, respectively). The recovery time of visual and optical quality in the first month after SMILE correlated with preoperative refraction and the amount of postoperative scattering. Patients with low myopia recovered visual acuity faster and with less ocular scattering than patients with moderate or high myopia. [J Refract Surg. 2019;35(5):285-293.].

The Relationship between Progression in Axial Length/Corneal Radius of Curvature Ratio and Spherical Equivalent Refractive Error in Myopia.

This study demonstrates that mean axial length/corneal radius of curvature ratio (AL/CR) can be used to detect low and high myopia but cannot clinically monitor myopia progression because the relationship between AL/CR and progression in myopia is different between low and high myopia. The purpose of this study was to investigate the relationship of AL/CR with magnitude and progression of myopia. Retrospective analysis was conducted comparing the right eyes of those with high myopia (n = 308; age, 7 to 16 years; myopia sphere, -6.00 diopters or worse) with those with low myopia (n = 732; age, 7 to 16 years; myopia sphere, between -0.50 and -3.50 diopters; cylinder, ≤1.00 diopters). Baseline axial length, corneal radii of curvature, and cycloplegic objective refraction were analyzed. Myopia progression in the low-myopia group at 6- and 12-month follow-up was measured, and the differences in slopes of AL/CR were compared for slow (<0.75 diopters) and fast progressing (≥0.75 diopters). Mean AL/CR values were significantly different (P < .001) between high myopia (3.46 ± 0.10) and low myopia (3.16 ± 0.07). In high and low myopia, slopes of axial length versus corneal curvature radius were not significantly different (P > .05), and slopes of AL/CR versus spherical equivalent were significantly different after adjusting for spherical equivalent and age (P < .05). Slopes of AL/CR progression and spherical equivalent progression were significantly different in low myopia between fast and slow progressing (P < .001), but the relationship between progression in AL/CR and progression in spherical equivalent was not strong. The AL/CR can be used to classify different grades of myopia, but it is not useful in determining the magnitude of myopia or monitoring progression because AL/CR is not linearly related to spherical equivalent and because progression in AL/CR is not strongly related to spherical equivalent progression.

The Synergistic Effects of Orthokeratology and Atropine in Slowing the Progression of Myopia.

Atropine and orthokeratology (OK) are both effective in slowing the progression of myopia. In the current study, we studied the combined effects of atropine and OK lenses on slowing the progression of myopia. This retrospective study included 84 patients who wore OK lenses and received atropine treatment (OA) and 95 patients who wore OK lenses alone (OK) for 2 years. We stratified patients into low (<6 D, LM) and high (≥6 D, HM) myopia groups, as well as two different atropine concentrations (0.125% and 0.025%). Significantly better LM control was observed in OA1 patients, compared with OK1 patients. Axial length was significantly shorter in the OA1 group (24.67 ± 1.53 mm) than in the OK1 group (24.9 ± 1.98 mm) (p = 0.042); similarly, it was shorter in the OA2 group (24.73 ± 1.53 mm) than in the OK2 group (25.01 ± 1.26 mm) (p = 0.031). For the HM patients, OA3 patients compared with OK3 patients, axial length was significantly shorter in the OA3 group (25.78 ± 1.46 mm) than in the OK3 group (25.93 ± 1.94 mm) (p = 0.021); similarly, it was shorter in the OA4 patients (25.86 ± 1.21 mm) than in the OK4 patients (26.05 ± 1.57 mm) (p = 0.011). Combined treatment with atropine and OK lenses would be a choice of treatment to control the development of myopia.

Single-step Transepithelial photorefractive keratectomy in the treatment of mild, moderate, and high myopia: six month results

BackgroundTo evaluate the safety, efficacy, and the refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) for the correction of mild, moderate, and high myopia.MethodsThis study consecutively recruited 32 high myopic eyes, 32 mild myopic and 32 moderate myopic eyes. Eyes with myopia that had undergone TransPRK treatment. Pre- and post-operative visual and refractive data, corneal Higher Order Aberration (HOA) as well as safety and efficacy indices were analyzed at 6 months postoperatively.ResultsSix months after TransPRK, the manifest refraction spherical equivalent (SE) was not significantly between high myopia group and moderate myopia group (p = 0.636). No eyes lost ≥2 lines of corrected distant visual acuity (CDVA) in high myopic eyes. The uncorrected distance visual acuity (UDVA) was significantly higher in low and moderate myopia groups than the high myopia group (P < 0.001; P = 0.002). The CDVA was not significantly different between moderate and high myopia groups (P = 0.057). There was no significant difference in mean safety index between high myopia group (1.01 ± 0.14) and mild myopia group (1.08 ± 0.15) (P > 0.05). The mean safety index was significantly higher in the moderate myopia group (1.16 ± 0.23) than in the high myopia group (1.01 ± 0.14) (P = 0.002). The efficacy index was significantly higher in the moderate myopia group (1.05 ± 0.20) than in the high myopia group (0.89 ± 0.17) (P = 0.02), and there was no significant difference between the high myopia group (0.89 ± 0.17) and the low myopia group (0.96 ± 0.16) (P = 0.14).ConclusionsThe mean safety index was over 1.0 in the three groups. TransPRK showed acceptable safety and efficacy in the moderate myopic eyes, as well as mild and high myopic eyes. High myopic eyes got very similar refractive results with moderate myopic eyes six months postoperatively. The safety and efficacy indexes were not significantly different between the high myopia group and the low myopia group.

Effectiveness of Glaucoma Diagnostic Parameters from Spectral Domain-Optical Coherence Tomography of Myopic Patients.

Background:Currently, spectral-domain optical coherence tomography (SD-OCT) appears to be a new type of glaucoma diagnostic tool. Thus, this study aimed to evaluate the effectiveness of glaucoma diagnostic parameters from SD-OCT of patients with different severities of myopia.Methods:This was a cross-sectional study. A total of 248 participants (248 eyes) were enrolled, including 51 cases in the early primary open-angle glaucoma group, 79 cases in the control group (0.50 D to −0.50 D, excluding −0.50 D), 47 cases in the low-myopic group (−0.50 to −3.00 D, excluding −3.00 D), 43 cases in the moderate-myopic group (−3.00 to −6.00 D, excluding −6.00 D), and 28 cases in the high-myopic group (≤−6.00 D). All participants were examined using the Humphrey visual field test and SD-OCT. The SD-OCT parameters of the retinal nerve fiber layer (RNFL) and ganglion cell complex were analyzed statistically using the receiver operating characteristic curve and area under the curve (AUC).Results:The AUC showed that the best parameters for the control and low-myopic groups were the inferior and inferior temporal RNFL thicknesses (AUC >0.94), respectively; for the moderate- and high-myopic groups, the best parameter was the temporal low RNFL thickness (AUC, 0.926 and 0.896, respectively). The AUC of the inferior parameters of the moderate-myopic group (0.864) was lower, ranked 15th among all RNFL parameters. When the sensitivity was fixed at 85%, the specificity of the inferior, superior, inferior temporal, and superior temporal quadrants was higher (>80%) in the control and low-myopic groups, while they were lower (20–60%) for the moderate- and high-myopia groups. The green color based on the OCT database was also less for the high-myopic group compared with that of other groups (P < 0.05).Conclusions:Glaucoma diagnostic parameters from SD-OCT were not clinically effective for the moderate- and high-myopic groups. The specificities were low. The moderate- and high-myopic groups require comprehensive analyses for the diagnoses of glaucoma. The SD-OCT database should be improved to better indicate the level of myopia based on the corresponding diopter readings.

Distribution of choroidal thickness and its influencing factors in undergraduate students of Tianjin Medical University

Objective To explore the distribution of choroidal thickness and its influence factors in university students. Methods A cross-sectional study. A total of 896 eyes of 896 college students were included in the study. Among them, there were 350 males (350 eyes) and 546 females (546 eyes). All the eyes were right eyes. The average age was 19.18 ± 1.36 years old. According to the spherical equivalent refraction (SER), the eyes were divided into non-myopia group, low myopia group, moderate myopia group and high myopia group, which were 59, 251, 356 and 230 eyes, respectively. The subfoveal ChT (SFCT) was measured using a swept-frequency source optical coherence tomography scanner. According to the ETDRS, the choroid within 6 mm of the fovea was divided into three concentric circles centered on the fovea of the macula, which were the central area with a diameter of 1 mm, the inner ring area of 1-3 mm and the outer ring area of 3-6 mm. The outer ring area of 3-6 mm has a total of 9 zones. The inner ring and outer ring 4 regions were superior, inferior, nasal and temporal, respectively. The distribution characteristics of ChT in different regions, genders and diopter groups were observed. Bivariate correlation analysis were used to analyze the correlation of ChT and SER, axial length (AL). Results The average SFCT of 896 eyes was 221.28±67.35 μm. The mean SFCT of males and females were 227.20±69.38 and 217.50±65.80 μm, respectively. The difference of SFCT between different genders was statistically significant (t=2.075, P=0.038). Compared with the central region ChT, there was no significant difference in ChT between the outer ring and the outer region (t=0.086, P=0.932). The difference of ChT in other regions was statistically significant (t=-21.973, -5.818, 36.328, -3.065, -18.017,-10.595, 57.007; P<0.001, <0.001, <0.001, <0.002, <0.001, <0.001, <0.001). In the horizontal direction, ChT gradually thickens from nasal to temporal (F=2 251.558, P<0.001); in the vertical direction, ChT gradually decreases from superior to the central, but have a little increased from central to inner inferior, then decreased to outer inferior again (F=45.425, P<0.05). Correlation analysis showed that SFCT was negatively correlated with AL (r=0.478, P<0.01) and a negative correlation with axial length (r=−0.395, P<0.01), and positively correlated with SER (r=0.478, P<0.01). SFCT decreased by 12.29 μm for every in myopic refractive error of 1 D, or by 20.14 μm for every increase in AL of 1 mm. Conclusions ChT is changed by different location. The horizontal direction is gradually thickened from nasal to temporal. The vertical direction is thicker than the center. The inferior inner ring area is thicker than the outer ring area. Gender, SER and AL are the influencing factors of SFCT. Key words: Macula/physiology; Choroidal thickness; Refractive error; Optical coherence tomography; Influence factors

Measurement of anterior segment parameters in Saudi adults with myopia

PurposeTo measure anterior segment parameters of the eye in myopic Saudi population using Pentacam. MethodThis is retrospective cross-sectional study. Subjects were divided into three groups: low, moderate and high myopia groups. Anterior segment parameters including: central corneal thickness (CCT), thinnest corneal thickness (TCT), apex corneal thickness (Apex CT), corneal volume (CV), anterior chamber depth (ACD), anterior chamber volume (ACV) and corneal astigmatism (CA) were measured by Pentacam. ResultsA total of 504 eyes of 252 Saudi subjects with myopia were included in this study. The mean age ± standard deviation (SD) of subjects was 28.73 ± 6.18 years. The mean CCT, TCT, Apex CT, CV, ACD, ACV and CA for all myopic subjects were 557.21 ± 29.36, 554.09 ± 29.28, 556.10 ± 37.06, 61.30 ± 3.23 μm, 3.31 ± 0.27 mm, 211.15 ± 34.22 mm3 and 0.89 ± 0.52 D, respectively. No significant differences (P > 0.05) were found between right and left eyes in all anterior segment parameters of all myopic eyes. However, a significant difference (P < 0.05) was found in ACD between low (3.27 ± 0.26 mm) and moderate (3.35 ± 0.30 mm) myopic groups. Within low myopia group, significant differences (P < 0.05) were found in ACD, ACV and CA between different genders. Anterior chamber depth and ACV values were lower in females while CA was lower in males. In addition, significant positive correlation was found between ACV and ACD in all myopic groups. ConclusionThis study provided valuable measurements of the anterior segments parameters of the eye in myopic Saudi population. These parameters could be useful for ophthalmic practitioners in the clinic.