In Vivo Corneal Biomechanical Response to Three Different Laser Corneal Refractive Surgeries.

PURPOSE: To compare the effects of three common refractive surgeries on corneal biomechanics. METHODS: Two hundred seven patients who had refractive surgery were included in this study, of whom 65 received transepithelial photorefractive keratectomy (tPRK), 73 received femtosecond laser-assisted laser in situ keratomileusis (FSLASIK), and 69 received small incision lenticule extraction (SMILE). Each patient had biomechanical measurements using the Corvis ST (Oculus Optikgeräte GmbH) preoperatively and at 3 and 6 months postoperatively. The measurements included five parameters expected to be associated with corneal biomechanics: deformation amplitude ratio at 2 mm (DAR2), integrated inverse radius (IIR), stiffness parameter at first applanation (SP-A1), highest concavity time (HCT), and the updated stress-strain index (SSIv2). The variations in these parameters postoperatively among the three surgeries, and their relationship with corneal thickness (CCT) and intraocular pressure measured by the Dynamic Contour Tonometer (DCT-IOP) were analyzed. RESULTS: SP-A1 decreased significantly from preoperatively to 3 months postoperatively in all three groups, whereas DAR2 and IIR increased significantly, all indicating stiffness losses. Between 3 and 6 months postoperatively, the results were inconsistent, with DAR2 decreasing (indicating stiffness increases) and IIR increasing (denoting stiffness decreases) in the FS-LASIK and SMILE groups. The decrease in SSIv2 (the only measure of corneal material stiffness) postoperatively was comparatively less pronounced at both 3 and 6 months postoperatively. On the other hand, HCT remained generally stable after all three surgeries. Unlike DAR2, IIR, and SP-A1, the changes postoperatively in stiffness parameters HCT and SSIv2 were independent of the corresponding changes in both DCT-IOP and CCT. CONCLUSIONS: Among the stiffness parameters considered, SSIv2 was not correlated with CCT or DCT-IOP, and holds promise for representing the corneal material stiffness and how it remains largely unaffected by refractive surgeries. Overall, FS-LASIK had the most significant impact on corneal stiffness, followed by SMILE, and finally tPRK. [J Refract Surg. 2024;40(5):e344-e352.].

The corneal biomechanical differences after wearing orthokeratology lenses and multifocal soft lenses in children: A self-control study.

BACKGROUND: To compare the changes in corneal biomechanics after orthokeratology (OK) lens and Defocus Incorporated Soft Contact (DISC) lens treatment. METHODS: Of 28 myopic children were recruited, with one eye wearing OK lens and the other eye wearing DISC lens for one year, and the data after discontinued for 4 weeks were also collected. Major outcomes were corneal biomechanics and axial length (AL) elongation. RESULTS: Throughout the follow-up period, the DISC group had longer the first applanation (A1) time, larger A1 deformation amplitude, A1 deflection length (A1 DLL), and A1 deflection amplitude than the OK group. AL elongation was less in the OK group at each visit (all P < 0.05) but faster in the OK group than in the DISC group after discontinuation (P = 0.006). Moreover, AL elongation was related to baseline A1 time, A1 velocity and whole eye movement max in the DISC group, and in the OK group, was related to the baseline the second applanation (A2) DLL, A2 delta arc length and stiffness parameter A1 (all P < 0.05). CONCLUSIONS: The cornea was more deformable after wearing DISC lens than OK lens, and corneal biomechanical parameters were associated with AL elongation. Eyes showed less AL elongation during OK lens treatment while faster AL elongation after discontinuation than DISC lens. The baseline corneal biomechanics may help to predict AL elongation in myopic control strategies.

Changes of optical coherence tomographic hyperreflective foci in rhegmatogenous retinal detachment patients after successful surgery.

PURPOSE: To assess the changes of hyperreflective foci (HRF) in rhegmatogenous retinal detachment (RRD) patients after successful reattachment surgery. METHODS: Twenty-nine macula-off RRD eyes with successful reattachment surgery were retrospectively analyzed. Optical coherence tomography (OCT) was used to image macular regions and measure HRF in outer retina and inner retina at 0.5, 1, 3, 6, 12 months after surgery. The relationships between HRF and photoreceptor layer status, visual outcomes were evaluated. RESULTS: After retinal reattachment, HRF mainly distributed at the location where external limiting membrane (ELM) or inner and outer segment (IS/OS) line was disrupted. The HRF numbers in outer and inner retina were greater in eyes with discontinuous IS/OS line than eyes with continuous IS/OS line (all p<0.05). In the outer retina,  HRF increased in the initial three months after retinal reattachment, and then decreased gradually after 3 months (p<0.05). The HRF number in the outer retina at postoperative 0.5 months was associated with favorable visual outcomes at 6 and 12 months (r=-0.487,  p =0.025; r=-0.626,  p=0.005, respectively), nevertheless, the HRF number at 3 months was correlated with poor visual results at 6 and 12 months (r=0.441,  p =0.017; r=0.477,  p=0.019, respectively). CONCLUSION: HRF mainly occurred near the site where ELM or IS/OS line was injured after retinal reattachment. In the outer retina, the number of HRF gradually increased in the first 3 months and then gradually decreased. The early appearance of HRF in the outer retina was associated with a good visual prognosis, while the late appearance may suggest a less favorable visual outcome.

Inter-examiner and intra-examiner reliability of optical coherence tomography angiography in vascular density measurement of retinal and choriocapillaris plexuses in healthy children aged 6-15 years.

Objective: This study aimed to test the inter-examiner and intra-examiner reliability of macular vascular density (VD) measurement of retinal and choriocapillaris plexuses in healthy children using optical coherence tomography angiography (OCTA). Materials and methods: Ninety-two school children were prospectively recruited. Macular OCTA images (6 × 6 mm2) were obtained thrice by two examiners using the RTVue-XR Avanti OCT system. The coefficient of variation (COV), intraclass correlation coefficient (ICC), and Bland-Altman plots were used to evaluate the repeatability and reproducibility. Results: Ninety participants aged 6-15 years were enrolled; two participants were excluded because of low-quality images. In the retina, the reproducibility and repeatability of VD became poorer from superficial to deep retinal capillary plexus (superficial: COV = 4.61-11.11%; intermediate: COV = 7.73-14.15%; deep: COV = 14.60-32.28%). For both reproducibility and repeatability, the ICC ranged from moderate to high (superficial plexus: ICC = 0.570-0.976; intermediate plexus: ICC = 0.720-0.968; deep plexus: ICC = 0.628-0.954). In the choroid, the inter-examiner reproducibility and intra-examiner repeatability of the VD measurement of choriocapillaris were excellent in the macula, fovea, parafovea, and perifovea (COV = 1.00-6.10%; ICC = 0.856-0.950). The parameters of the foveal avascular zone (FAZ) also showed significant reproducibility and repeatability (COV = 0.01-0.21%; ICC = 0.743-0.994). Conclusion: The VD measurements of the choriocapillaris and FAZ parameters using OCTA showed excellent inter-examiner and intra-examiner reliability in school children. The reproducibility and repeatability of the VD of three retinal capillary plexuses depended on the depth of the retinal capillary plexus.

Precision (repeatability and reproducibility) of papillary and peripapillary vascular density measurements using optical coherence tomography angiography in children.

Importance: Optical coherence tomography angiography (OCTA) has been widely applied into children, however, few studies have assessed the repeatability and reproducibility of papillary and peripapillary VD in healthy children. Objective: To assess the precision of papillary and peripapillary vascular density (VD) measurements using optical coherence tomography angiography (OCTA) and analyze the effects of the signal strength index (SSI) and axial length (AL) on precision estimates. Design setting and participants: This was a prospective observational study. Seventy-eight children aged 6-16 years underwent 4.5 × 4.5 mm OCTA (RTVue XR Avanti) disc scans: two scans by one examiner (repeatability) and two additional scans by another examiner (reproducibility). Within-subject standard deviation (Sw), test-retest reproducibility (TRT), within-subject coefficient of variation (CoV), intraclass correlation coefficient (ICC), and Bland-Altman analysis were performed. Main outcomes and measures: In repeatability measurement, the fluctuation ranges (minimum to maximum) of VD between intraexaminer A/B in Sw, TRT, CoV, and ICC were (1.05-2.17)% / (1.16-2.32)%, (2.9-6)% / (3.21-6.44)%, (1.9-4.47)% / (2.08-5)%, and (0.588-0.783)% / (0.633-0.803)%, respectively. In reproducibility measurement, the fluctuation ranges of VD in Sw, TRT, CoV, and ICC were 1.11-2.13%, 3.07-5.91%, 1.99-4.41%, and 0.644-0.777%, respectively. VD was negatively correlated with SSI in most sectors of the peripapillary (e.g., inferior nasal, temporal inferior, temporal superior, superior temporal, and superior nasal). AL was positively correlated with inferior temporal VD and negatively correlated with superior nasal VD. Conclusion and relevance: Optical coherence tomography angiography showed moderate-to-good repeatability and reproducibility for papillary and peripapillary perfusion measurements in healthy children. The SSI value affects most of the peripapillary VD, while AL affects only the temporal inferior and nasal superior peripapillary VD.

The influence of overnight orthokeratology and soft contact lens on the meibomian gland evaluated using an artificial intelligence analytic system.

PURPOSE: To test the changes of meibomian gland (MG) morphology using an artificial intelligence (AI) analytic system in asymptomatic children wearing overnight orthokeratology (OOK) and soft contact lens (SCL). METHODS: A retrospective study was conducted including 89 participants treated with OOK and 70 participants with SCL. Tear meniscus height (TMH), noninvasive tear breakup time (NIBUT), and meibography were obtained using Keratograph 5 M. MG tortuosity, height, width, density, and vagueness value were measured using an artificial intelligence (AI) analytic system. RESULTS: In an average of 20.80 ± 10.83 months follow-up, MG width of the upper eyelid significantly increased and MG vagueness value significantly decreased after OOK and SCL treatment (all P < 0.05). MG tortuosity of the upper eyelid significantly increased after OOK treatment (P < 0.05). TMH and NIBUT did not differ significantly pre- and post- OOK and SCL treatment (all P > 0.05). The results from the GEE model demonstrated that OOK treatment positively affected MG tortuosity of both upper and lower eyelids (P < 0.001; P = 0.041, respectively) and MG width of the upper eyelid (P = 0.038), while it negatively affected MG density of the upper eyelid (P = 0.036) and MG vagueness value of both upper and lower eyelids (P < 0.001; P < 0.001, respectively). SCL treatment positively affected MG width of both upper and lower eyelids (P < 0.001; P = 0.049, respectively) as well as MG height of the lower eyelid (P = 0.009) and tortuosity of the upper eyelid, (P = 0.034) while it negatively affected MG vagueness value of both upper and lower eyelids (P < 0.001; P < 0.001, respectively). However, no significant relationship was found between the treatment duration and TMH, NIBUT, MG morphological parameters in OOK group. SCL treatment duration negatively affected MG height of the lower eyelid (P = 0.002). CONCLUSIONS: OOK and SCL treatment in asymptomatic children can influence MG morphology. The AI analytic system may be an effective method to facilitate the quantitative detection of MG morphological changes.

PATHOLOGIC STUDY OF UNTREATED INTRARETINAL GLIOSIS SURGICALLY EXCISED VIA PARS PLANA VITRECTOMY.

PURPOSE: To evaluate the pathologic process of intraretinal glioses by investigating mass tissues resected from untreated eyes with intraretinal glioses. METHODS: Five patients with intraretinal gliosis without previous conservative treatment were included. All patients underwent pars plana vitrectomy. The mass tissues were excised and processed for the pathologic study. RESULTS: During surgery, it was observed that the intraretinal gliosis mainly affected the neuroretina and the retinal pigment epithelium was not affected. Pathologic examination revealed that all intraretinal glioses consisted of different proportions of hyaline vessels and hyperplastic spindle-shaped glial cells. In one case, the intraretinal gliosis was mainly composed of hyaline vascular components. In another case, the intraretinal gliosis showed a predominance of glial cells. The intraretinal glioses in the other three cases had vascular and glial components. The proliferated vessels showed different amounts of collagen deposits against different backgrounds. Vascularized epiretinal membrane was found in some intraretinal glioses. CONCLUSION: Intraretinal glioses affected the inner retinal layer. Hyaline vessels were the most characteristic pathologic changes; the proportion of proliferative glial cells varied in different intraretinal glioses. The natural course of intraretinal gliosis may involve the proliferation of abnormal vessels in the early stage, which then gradually become scarred and are replaced by glial cells.

Uneven Meibomian Gland Dropout in Patients with Meibomian Gland Dysfunction and Demodex Infestation.

The purpose of this study was to compare the differences between uneven meibomian gland (MG) atrophy with and without Demodex infestation based on the index of uneven atrophy score (UAS). In this retrospective cohort study, 158 subjects were recruited, including 66 subjects in the Demodex-positive MGD group, 49 subjects in the Demodex-negative MGD group, and 43 subjects as normal control. No significant difference was verified in OSDI, TMH, TBUT, CFS, lid margin score, and meibograde (all p > 0.05) between the Demodex-positive MGD group and the Demodex-negative MGD group. The UAS index of the upper eyelid or both eyelids was significantly higher in the Demodex-positive group in comparison with the normal control group and Demodex-negative group and the difference was statistically significant between the three groups. The UAS was significantly positive correlation with OSDI (r = 0.209, p < 0.05), lid margin score (r = 0.287, p < 0.001), and meibograde (r = 0.356, p < 0.001), which has a significant negative correlation with TBUT (r = −0.248, p < 0.05). Thus, Demodex infestation can cause uneven MG atrophy and we propose a novel index of UAS, which is used to evaluate uneven atrophy of MGs and as a morphological index of Demodex infestation.

Normative Data and Determinants of Macular, Disc, and Peripapillary Vascular Density in Healthy Myopic Children Using Optical Coherence Tomography Angiography.

Objective: To establish a normative database for the vascular density (VD) in macular, disc, and peripapillary regions in healthy myopic children and to evaluate associated ocular features with optical coherence tomography angiography (OCTA). Methods: This was an observational, prospective and cross-sectional study. 776 Chinese healthy myopic children (375 boys and 401 girls) were enrolled, mean (±SD) age 9.84 ± 1.98 (range 6-16) years. En-face angiogram OCTA was performed on 6 mm × 6 mm retinal and 4.5 mm × 4.5 mm disc regions. VD measurements in the macular retina were segmented into the four regions: superficial capillary plexus (SCP), intermediate capillary plexus (ICP), deep capillary plexus (DCP), and choriocapillaris (CC). Correlations between macular, disc, and peripapillary VD and possible influencing factors [age, gender, axial length (AL), spherical equivalent refraction (SER), right/left eye, and signal strength index (SSI)] were assessed by Pearson's correlation and multivariate regression analysis. Results: For macular scans, the corrected VD in the ICP region was (48.25 ± 4.24)% for the whole macular retina. The macular ICP VD in most sections was lower than the SCP, DCP, and CC (all P < 0.001). The corrected VD in CC was (72.96 ± 4.42)% for the whole macular retina. The macular CC VD in every section was all higher than the SCP, ICP, and DCP (all P < 0.001). The size of foveal avascular zone (FAZ) and foveal VD 300 (FD-300) was 0.28 mm2± 0.10 mm2 and (58.43 ± 4.17)% respectively. For disc scans, the corrected VD was (58.04 ± 2.73)% for the whole disc area. Both AL and SER were strongly correlated with ICP, DCP, and CC VD in all regions (all P < 0.01). Larger SSI was correlated with a lower VD in the SCP and ICP, and a higher VD in DCP and CC (all P < 0.01). Conclusion: Vascular density values provide large scale normative data on macular, disc, and peripapillary vascular parameters in a large sample of healthy myopic children with OCTA measured in the four different retinal plexuses and regions. The VD in different regions had various influencing factors; mainly a close correlation with AL and SSI.

Efficacy of Combined Phacoemulsification and Goniosynechialysis in Primary Angle Closure Disease With Different Degrees of Peripheral Anterior Synechiae.

PRCIS: Phacoemulsification and goniosynechialysis (Phaco-GSL) was equally effective in the treatment of primary angle-closure disease (PACD) with preoperative peripheral anterior synechiae (PAS) <180 degrees and larger than 180 degrees. Patients with a larger preoperative PAS range required more range of mechanical separation intraoperatively and displayed more recurrence of PAS (re-PAS) range postoperatively. PURPOSE: To evaluate the long-term efficacy of combined phaco-GSL in PACD with different extent of PAS. PATIENTS AND METHODS: A retrospective study was conducted on 67 patients (79 eyes) who received phaco-GSL. The patients were divided into 2 groups according to the extent of PAS (group A: PAS ≤180 degrees; group B: PAS >180 degrees). Changes in intraocular pressure (IOP), the number of anti-glaucoma drugs, intraoperative mechanical separation of PAS and range of re-PAS during the last follow-up ≥12 months were analyzed. RESULTS: At baseline, eyes in group B presented with higher IOP and more anti-glaucoma drugs usage ( P =0.008 and 0.004). The PAS range, IOP, number of anti-glaucoma medication were reduced both in 2 groups at the final visit. The range of mechanical separation intraoperatively and re-PAS postoperatively were both larger in group B ( P =0.002 and <0.001). The postoperative re-PAS range was positively correlated with the range of mechanical separation ( R2 =0.17). The complete success rates at 12, 24, 36, and 48 months were 86.8%, 71.1%, 71.1%, and 71.1% in group A; and 80.5%, 74.6%, 69.9%, and 69.9% in group B. The qualified success rates were 100%, 96.6%, 92.0%, and 92.0% in group A; and 100%, 89.5%, 85.1%, and 85.1% in group B. CONCLUSION: Phaco-GSL for the treatment of PACD showed equally effective IOP control regardless of the extent of preoperative PAS.

Characteristics of the Optic Nerve Head in Myopic Eyes Using Swept-Source Optical Coherence Tomography.

Purpose: To investigate the characteristics of the optic nerve head (ONH) in myopia using swept-source optical coherence tomography (SS-OCT). Methods: Participants were divided into three groups according to the axial length (AL). The optic disc morphology, retinal nerve fiber layer (RNFL) thickness, and radial peripapillary capillary (RPC) vessel density (VD), optic disc tilt, rotation, Bruch's membrane opening distance (BMOD), border length (BL), border tissue angle, focal lamina cribrosa (LC) defects, ß- and γ-zone peripapillary atrophy (PPA), microvasculature dropout (MvD), choroidal thickness (CT), and the choroidal vascularity index (CVI) were compared. Linear regression analysis evaluated relationships between spherical equivalent, AL, and ONH parameters. Results: One hundred five, 98, and 118 eyes were included in groups 1, 2, and 3, respectively. With AL increasing, the mean, superior and temporal CT, central mean and temporal, pericentral mean, inferior and nasal RPC VD, and temporal CVI decreased, whereas the mean and temporal RNFL thickness, optic disc, RIM and ß-PPA area, presence and area of γ-PPA, BMOD and BL increased. Compared to other groups, group 3 depicted a larger cup area, more focal LC defect and total and juxtapapillary MvD; a lower central superior, inferior and nasal, pericentral superior, and temporal RPC VD. Group 1 demonstrated more tilted disc, larger inferior and nasal CT, mean, superior, inferior, and nasal CVI. Conclusions: Myopia eyes have larger ONH changes, PPAs, regional RNFL, and MvD, but smaller regional CTs, RPC VD, and CVIs. SS-OCT may be useful in detecting ONH variations during myopia.

Choroidal Vascularity Index Changes After Exercise in Patients With Glaucoma.

Purpose: To investigate the changes in choroidal vascular structures after exercise in patients with glaucoma using an image binarisation algorithm with enhanced-depth imaging optical coherence tomography. Methods: Thirty-four eyes of 19 patients with primary open-angle glaucoma and 40 eyes of 20 normal subjects were included in the glaucoma and control groups, respectively. All subjects were evaluated before, immediately after, and 30 min after 20-min running at moderate speed. The subfoveal choroidal area was segmented into the luminal area (LA) and stromal area (SA), and the choroidal vascularity index (CVI) was measured by calculating the ratio of LA to the total choroidal area (TCA). The mean intraocular pressure (IOP), subfoveal choroidal thickness, CVI, SA, CA, and TCA were compared within and between both groups. The correlation between CVI, IOP, and other vascular indexes was investigated. Results: In the glaucoma group, a significantly lower CVI was found immediately after exercise and recovered 30 min after exercise. Higher TCA and LA levels were demonstrated 30 min after exercise compared to immediately after exercise. In both groups, IOP decreased immediately after exercise but was restored after a 30-min rest. In the glaucoma group, there was a higher correlation between CVI and other choroidal vascular parameters than in the control group. There was no difference in IOP or choroidal parameters between the groups at different time points. Conclusion: In patients with glaucoma, CVI decreased significantly immediately after exercise, indicating that the choroidal layer is affected by exercise and an unhealthy vascular regulatory mechanism.

Characteristics of macular microvasculature before and after idiopathic macular hole surgery.

AIM: To evaluate the macular microvasculature before and after surgery for idiopathic macular hole (MH) and the association of preoperative vascular parameters with postoperative recovery of visual acuity and configuration. METHODS: Twenty eyes from 20 patients with idiopathic MH were enrolled. Optical coherence tomography angiography (OCTA) images were obtained before, 2wk, 1, and 3mo after vitrectomy with internal limiting membrane peeling. Preoperative foveal avascular zone (FAZ) area and perimeter and regional vessel density (VD) in both layers were compared according to the 3-month best-corrected visual acuity (BCVA). RESULTS: The BCVA improved from 0.98±0.59 (logMAR, Snellen 20/200) preoperatively to 0.30±0.25 (Snellen 20/40) at 3mo postoperatively. The preoperative deep VD was smaller and the FAZ perimeter was larger in the 3-month BCVA<20/32 group (all P<0.05). A significant reduction was observed in FAZ parameters and all VDs 2wk postoperatively. Except for deep perifoveal VD, all VDs recovered only to their preoperative values. The postoperative FAZ parameters were lower during follow-up. Decreases in preoperative deep VDs were correlated with worse postoperative BCVA (Pearson's r=-0.667 and -0.619, respectively). A larger FAZ perimeter (Spearman's r=-0.524) and a lower deep perifoveal VD preoperatively (Pearson's r=0.486) were associated with lower healing stage. CONCLUSION: The status of the deep vasculature may be an indicator of visual acuity in patients with a closed MH. Except for the deep perifoveal region, VD recovers only to preoperative levels.

Association between Iris Biological Features and Corneal Biomechanics in Myopic Eyes.

PURPOSE: Iris biological features such as surface features and profile characteristics reflected the development of iris stroma and microvessels. Iris vessels and microcirculation are still lack of effective detection methods, and we can directly observe only the iris surface biological characteristics. This cross-sectional study evaluated the association between iris surface biological features and corneal biomechanics in young adults with myopia. METHODS: We recruited 152 patients with myopia aged ≥18 years, from the Eye Hospital of Wenzhou Medical University, who had complete Corneal Visualization Scheimpflug Technology (Corvis ST) data and graded iris surface features. Iris surface features included crypts, furrows, and color measured from digital slit lamp images. The biomechanical properties of the cornea were assessed using Corvis ST. Only 1 eye of each participant was randomly selected for analysis. Associations between the iris surface features and corneal biomechanics were analyzed using linear regression models. The grade of iris crypts, furrows, and color and corneal biomechanical parameters measured with Corvis ST was the main outcome measures. RESULTS: The iris crypts were significantly associated with deflection amplitude at the first applanation (A1 DLA, ß = 0.001, P = 0.013), A1 delta arc length (A1 dArcL) (ß = -0.001, P = 0.01), maximum delta arc length (dArcLM) (ß = -0.004, P = 0.03), and stiffness at the first applanation (SP-A1) (ß = -2.092, P = 0.016). The iris furrows were only associated with integrated radius (ß = -0.212, P = 0.025). Iris color was found not related with corneal biomechanical parameters measured via Corvis ST. CONCLUSIONS: Iris surface features were associated with corneal biomechanical properties in myopic eyes; more iris crypts were associated with lower corneal stiffness while more extensive furrows were related with higher corneal stiffness. Iris crypts and furrows may provide useful information on corneal biomechanical properties in myopic eyes.

Association of Iris Structural Measurements with Corneal Biomechanics in Myopic Eyes.

PURPOSE: To evaluate the relationship between iris sectional parameters on swept-source optical coherence tomography (SS-OCT) with corneal biomechanics measured by Corneal Visualization Scheimpflug Technology (Corvis ST) in young adults with myopia. METHODS: 117 patients with myopia aged ≥18 years were recruited from the Eye Hospital of Wenzhou Medical University, who had complete SS-OCT and Corvis ST data. Only the left eye of each participant was selected for analysis. Iris sectional parameters included iris thickness at 750 µm from the scleral spur (IT750), iris sectional area (I-area), and iris curvature (I-curv) measured from four quadrants. Associations between the iris parameters and corneal biomechanics were analyzed using linear regression models. RESULTS: The mean age of the included young adults was 26.26 ± 6.62 years old with 44 males and 73 females. The iris parameters were different among the four quadrants. The nasal, temporal, and inferior quadrants of IT750, together with nasal and temporal quadrants of I-area, were correlated with corneal biomechanical parameters after being adjusted for age, gender, pupil diameter, and axial length. Thicker IT750 and larger I-area were related to a softer cornea. However, no association was found between I-curv and corneal biomechanics. CONCLUSIONS: Iris sectional parameters measured from SS-OCT images were associated with corneal biomechanical properties in myopic eyes. Thicker IT750 and larger I-area indicate a softer cornea. IT750 and I-area may provide useful information on corneal biomechanical properties in myopic eyes.

A Novel Quantitative Index of Meibomian Gland Dysfunction, the Meibomian Gland Tortuosity.

Purpose: To quantitatively measure meibomian gland (MG) tortuosity in meibomian gland dysfunction (MGD) patients and normal controls and to observe the efficacy of evaluating MG tortuosity for the diagnosis of MGD. Methods: This cross-sectional study enrolled 32 obstructive MGD patients and 28 normal volunteers. Clinical assessments were performed, including symptom questionnaires, tear meniscus height, tear break-up time (TBUT), corneal fluorescein staining, lid margin abnormality, MG expressibility, and meibography. The meibomian gland tortuosity and meibomian gland density were measured by VIA software. Results: The mean age of the patients in the MGD group was 33.28 ± 9.28 years, and that of the normal controls was 25.25 ± 11.19 years. The average tortuosity of all MGs in the MGD patients was significantly larger than in the normal controls (P< 0.05). We further stratified the MGD patients into symptomatic MGD and asymptomatic groups. The average tortuosity of all MGs and of the central eight MGs was significantly higher in the symptomatic MGD patients than in the asymptomatic MGD patients (P< 0.05). Significant linear correlations were found between MG tortuosity and the lid margin score, meiboscore, meibum expressibility score, and TBUT (P< 0.05). When the diagnosis of obstructive MGD was based on the tortuosity of the central eight MGs of both eyelids, the sensitivity and specificity were 100% and 100%, respectively. Conclusions: MG tortuosity is an effective index to delineate MG morphology and to diagnose MGD, especially for the diagnosis of early-stage MGD. Translation Relevance: Calculating tortuosity quantitatively may play an important role in the diagnosis of MGD.

The Effect of Treatment Zone Decentration on Myopic Progression during Or-thokeratology.

Purpose: To evaluate the relationship between magnitude of orthokeratology (OrthoK) treatment zone decentration and 2-year axial length (AL) elongation in myopic children.Methods: One-hundred and one Chinese children who wore OrthoK contact lenses for 2 years. The magnitude and direction of the OrthoK treatment zone center from the entrance pupil center were recorded after 3 and 24 months of lens wear along with AL measurement. Stepwise multiple linear regression analysis was performed to assess which factors significantly affected an increase in AL.Results: After 3 and 24 months of OrthoK treatment, the mean (± standard deviation [SD]) magnitude of the OrthoK treatment zone decentration was 0.64 ± 0.38 mm and 0.68 ± 0.32 mm, respectively. There were no significant differences between the two time points (P > .05). After 2 years of OrthoK contact lenses wear, the mean (± SD) AL growth was 0.36 ± 0.34 mm. The axial elongation was slightly correlated with baseline age of subjects (r = -0.073, P < .001), baseline spherical equivalent refractive error (r = -0.088, P < .001) and magnitude decentration of treatment zone (r = -0.190, P = .027).Conclusions: The decentration of OrthoK treatment zone stabilizes after 3 months of lens wear and slightly decreases AL growth.

Comparison of four different orthokeratology lenses in controlling myopia progression.

PURPOSE: To compare axial length (AL) elongation in myopic children with four Orthokeratology (OrthoK) lenses and spectacles. METHODS: The medical records of 266 patients (532 eyes) who were fitted with OrthoK lenses or spectacles (control group) were reviewed. Data collection included baseline age, gender, baseline objective sphere and cylinder, baseline flat and steep corneal meridian power, corneal asphericity coefficient (Q value), AL at baseline and after 1-year, and 2-years of OrthoK or spectacle wear analyzed using analysis of repeated measures data ANOVA. Stepwise linear regressions between the changes in AL after 2 years relative to baseline parameters were calculated for the OrthoK and control groups separately. RESULTS: The baseline subject parameters for each of the four OrthoK lenses were not statistically different. Statistically significant differences between time points were found between 12- and 24- months (all P < 0.05). AL growth was slower in all OrthoK groups than in the control group (all P < 0.05). AL grew 0.081±0.034 mm per year slightly less than average with Essence compared to the Mouldway OrthoK group (P = 0.019). The coefficient of regression weakly expressed between the increases in AL over 2-years study period and baseline spherical equivalent refraction was 0.065 in Essence, 0.079 in Euclid and 0.087 in Mouldway. The coefficient of regression was also weakly between age and the increases AL over 2-years study period and baseline age in all groups. CONCLUSION: Different OrthoK lenses differ minimally in slowing axial elongation effectively in myopic children during 2-years lens wear.

Comparative Study on the Efficacy and Safety of Tumor Resection in Vitrectomy for Retinal Vasoproliferative Tumors.

PURPOSE: To investigate the efficacy and safety of combined vitrectomy with tumor resection in the treatment of retinal vasoproliferative tumors (RVPT). METHODS: Retrospective study. RVPT patients who underwent vitreous surgery at the Eye Hospital of Wenzhou Medical University from January 2011 to July 2017 were included. The main outcomes included treatment type, tumor activity, and best-corrected visual acuity (BCVA). RESULTS: Altogether, 16 patients with 17 eyes were enrolled with follow-up of no less than 6 months. Eight eyes were in the resection treatment group (Group R) and 9 eyes were in the conservative treatment group (Group C). Female (69%) were more common. The mean age was 50 (49.72 ± 12.92) years. Fifteen patients got unilateral onset and only one patient suffered bilaterally. The common symptoms were decreased visual acuity, floaters, and visual distortion. The preoperative BCVA ranged from hand movement to 20/20, with an average of 0.82 ± 0.75 LogMAR. Patients were all not high myopia, with a mean axial length of 23.27 ± 0.27 mm (21.61 mm to 24.67 mm). Of the retinal diseases, the epiretinal membrane was the most common, followed by vitreous hemorrhage, uveitis, subretinal fluid, and so on. Compared with the baseline BCVA, it improved more at postoperative 6 months and the last visit in Group R than in Group C (P=0.006 and P=0.033). The BCVA-improved 0.2 LogMAR or above in 6 months was 2 eyes in Group C and 7 eyes in Group R. All tumors in Group R were completely resected, whereas three in Group C (33.3%) had definite activity (P=0.008). In all samples, tumors were located on the inner side of the retina and had small vessel wall thickening and hyaline degeneration. The degree of astrocyte proliferation varies widely among different tumors. CONCLUSIONS: RVPT was more likely to occur in nonhigh myopia patients. Epiretinal membrane and vitreous hemorrhage were the main causes for vitreous surgery in RVPT patients. Compared with conservative treatment, surgical resection of the tumor is more beneficial to patients on visual acuity recovery and preventing tumor relapse. It is a safe and effective way to treat RVPT.

The Effect of Anterior Capsule Polishing on Capsular Contraction and Lens Stability in Cataract Patients with High Myopia.

PURPOSE: To evaluate the effect of anterior capsule polishing in patients with high myopia after cataract surgery. SETTING: The Eye Hospital of Wenzhou Medical University, Zhejiang, China. DESIGN: Prospective study. METHODS: High myopic patients with a bilateral cataract who underwent phacoemulsification with 360° anterior capsular polishing in one eye and without polishing in the contralateral eye were recruited. The following parameters were recorded at 1, 3, and 6 months postoperatively, including the area and diameter of the anterior capsule opening (area and D), IOL tilt and decentration, refraction, and postoperative aqueous depth (PAD). RESULTS: Paired samples of 38 eyes of 19 patients were enrolled. The area decreased significantly in both the polished group and unpolished group, whereas the diameter reduced more in the unpolished group. The IOL tilt and decentration at 3-month and 6-month follow-up showed significant differences between two groups. In the unpolished group, the IOL decentration firstly appeared between one-month to three-month visit, while the refraction error, PAD, and IOL tilt were significantly different between the three-month and six-month visits. CONCLUSION: 360° anterior capsule polishing can effectively reduce the extent of the anterior capsule contraction and increase the stability of IOL. The study was registered at http://www.clinicaltrials.gov, and the clinical trial accession number is NCT 03142269.