Total Astigmatism Research Articles

Impact of quality indicators on variability of keratometry measurements using a swept-source OCT based optical biometer.

To characterize the variability of keratometry measurements on the IOLMaster 700, and relate it to device image quality indicators (QI). Two academic centers and one private practice. Multicenter, retrospective consecutive case series. Measurements from three sites, obtained between December, 2015 and July, 2023 were included. Surgery-naïve phakic eyes with same-day sequential measurements on the same eye were identified. Repeat measurement pairs were grouped by IOLMaster QIs (success vs. warning), and changes in mean standard (∆Kmean) and total (∆TKmean) keratometry as well as standard (∆Kastig) and total (∆TKastig) astigmatism vectors were calculated. Analysis was performed on 3,222 eyes of 1,890 patients. Measurement 'success' was associated with a smaller ΔKmean (0.09 ± 0.14 D) and ΔTKmean (0.11 ± 0.16 D) when compared to pairs in which both measurements had a 'warning' [0.25 ± 0.32 D and 0.14 ± 0.17 D, respectively; (p < 0.0001)]. A similarly smaller ∆Kastig (0.26 ± 0.28 D) and ∆TKastig (0.28 ± 0.30 D) was observed with measurement 'success' versus 'warning' [0.77 ± 0.79 D and 0.42 ± 0.41 D, respectively (p < 0.0001)]. Even when both measurements were successful, the proportion of measurement pairs that had a ∆Kastig > 0.50 D increased from 14% to 24% to 32% when Kmean standard deviation (SD) was ≥ 0.01, 0.05, and 0.10 D, respectively. When measurement quality is poor, total keratometry varies less than standard keratometry measurements. Clinicians may use the SD of Kmean/TKmean to estimate the repeatability of measurements and balance this against their tolerance for performing repeat measurements.

Corneal changes after large (9mm) lateral rectus muscle recession measured with Pentacam®

ABSTRACT Introduction: The aim of this study was to evaluate alterations in corneal astigmatism, axial anterior corneal curvature, anterior chamber depth, and central corneal thickness (CCT) two months after the unilateral recession of lateral rectus muscle in children. Methods: This prospective study included 37 children with intermittent exotropia who would undergo unilateral lateral rectus muscle recession. All measurements were performed using Pentacam®. Comparisons were made between the operated and fellow unoperated eyes, pre- and post-operatively. The assessment was made for changes in the radius of axial curvature on major meridians at 3 and 3.5 mm from the optical corneal center in the mid-peripheral zone. Astigmatism changes of the anterior and posterior corneal surface were calculated using vector analysis software (astigMATIC®). The interaction between age or CCT and postoperative changes in anterior and posterior surface corneal astigmatism were examined with ANOVA model. Results: In the intervention group, changes in anterior and posterior corneal surface astigmatism were statistically significant, with a mean increase of 0.56Dx90 and 0.08Dx87, respectively. In the mid-peripheral corneal zone, an increase was observed in the radius of anterior corneal axial curvature, more evident temporal 3 and 3.5 mm from the corneal center on the horizontal meridian, with corresponding decrease superiorly and inferiorly at 3 and 3.5 mm from the corneal center on the vertical meridian. Discussion: The changes in total astigmatism of the operated eyes are mainly attributed to the anterior corneal surface. These changes are associated with flattening in the 180 meridian of the cornea, leading to a shift to “with-the-rule” astigmatism.

Ocular dominance shift in refractive cataract surgery: prospective, observational study.

To explore the features of the dominant and nondominant eyes in patients with cataracts and predict ocular dominance shift (ODS) based on preoperative indicators. Changsha Aier Eye Hospital, Changsha, Hunan, China. Prospective, observational study. Patients with age-related cataracts who underwent unilateral cataract surgery were enrolled in this study. Before the procedure, uncorrected distance visual acuity (UDVA) was assessed and noncycloplegic subjective refraction evaluations were conducted to determine corrected distance visual acuity. Total astigmatism, corneal astigmatism, and intraocular astigmatism were measured using OPD-Scan III. Cataract type was assessed using slitlamp biomicroscopy based on the Lens Opacities Classification System III. Ocular dominance (OD) was determined under corrected conditions using the hole-in-card test. Follow-up visits occurred at 1 day, 1 week, and 1 month postoperatively. After 1 month, OD was re-evaluated, and participants completed the 9-item Short-Form Cataract Questionnaire. 94 patients (188 eyes) were enrolled in the study. The analysis showed that the ODS rate of unilateral cataract surgery was 40.4%. In addition, age, UDVA of the nondominant eye, posterior subcapsular cataract, and total astigmatism were risk factors for ODS. No difference in vision-related quality of life was detected between patients who had ODS and those who did not. Several preoperative parameters as potential risk factors of ODS after cataract surgery were identified. These findings provide guidance for predicting changes in the dominant eye and may improve the precise selection of intraocular lenses and implementation of monovision strategies.

Body mass index and astigmatism: A nationwide study.

Existing research on the relationship between body mass index (BMI) and astigmatism yields inconsistent results. This study analyses this association in a nationally representative sample of adolescents. This retrospective, cross-sectional study included Israeli adolescents who underwent medical assessments before mandatory military service between 2011 and 2022. BMI was categorised based on the US age- and sex-matched percentiles. Astigmatism was categorised by magnitude [low-moderate: 0.75 to <3.00 diopters (D), high: ≥3.00 D], and axis orientation [with-the-rule (WTR), against-the-rule (ATR), or oblique (OBL)]. Sex-stratified regression models adjusted for sociodemographic variables were used. Of 935 989 adolescents evaluated, 887 325 were included [511 465 (57.6%) males, mean age 17.2 years]. Astigmatism was diagnosed in 123 675 (13.9%) adolescents, of whom 117 081 (13.2%) had low-moderate and 6594 (0.7%) had high astigmatism. WTR astigmatism was the most prevalent (8.2%), followed by ATR (4.1%) and OBL (1.6%) types. Compared with low-normal BMI (5th to 50th percentile), the adjusted ORs for total astigmatism increased with increasing BMI, peaking at 1.65 (1.57-1.74) in males and 1.74 (1.64-1.86) in females with severe obesity. ORs were accentuated for high astigmatism, reaching 3.51 (3.01-4.09) in males, and 3.45 (2.83-4.22) in females with severe obesity. WTR astigmatism demonstrated the strongest association with BMI, with ORs reaching 2.26 (2.13-2.40) in males and 2.04 (1.90-2.20) in females with severe obesity. The results persisted in a series of subgroup analyses. Obesity is associated with higher odds of astigmatism in adolescence. Further investigation into the role of weight management in astigmatism development is warranted.

No Changes in Keratometry Readings and Anterior Chamber Depth after XEN Gel Implantation in Patients with Glaucoma.

Background: This study aimed to compare keratometry and anterior chamber depth (ACD) changes after XEN implantation in primary open-angle glaucoma (POAG) cases over a 3-month follow-up period. Methods: Twenty patients with POAG who underwent XEN63 implantation, either standalone or combined with cataract surgery, were included. Preoperative data, including best-corrected visual acuity (BCVA), refraction, gonioscopy, ophthalmoscopy, intraocular pressure (IOP) evaluation, and axial length, were collected. Corneal topography and ACD measurements were assessed preoperatively and at postoperative days 1, 7, 15, 30, 60, and 90. Each patient's eye that underwent XEN surgery was included in the study group, with the fellow eye serving as a control. Results: In the study group, there was a significant decrease in IOP after XEN stent implantation at all investigated time intervals (p < 0.05). However, changes in mean ACD did not show statistically significant differences at any follow-up examination in both the study and control groups. Additionally, keratometry readings revealed no significant changes in total astigmatism or steep keratometry values in either group. Conclusions: XEN implantation in POAG cases resulted in a significant decrease in IOP over the 3-month follow-up period. However, there were no significant changes observed in mean ACD or keratometry readings, indicating stability in these parameters post-XEN implantation. These findings suggest that XEN implantation may be an effective option for IOP reduction without affecting corneal curvature or ACD in POAG patients.

Corneal tomography changes following major (6 mm) medial rectus muscle recession: a prospective cohort study using Pentacam®

ABSTRACT Introduction The aim of this study is to evaluate changes in corneal astigmatism, axial anterior corneal curvature, as well as changes in the anterior chamber depth and central corneal thickness, 2 months following the unilateral recession of medial rectus muscle in children. Methods Thirty-three children with esotropia were prospectively evaluated following unilateral medial rectus muscle recession, using Pentacam®. Comparisons were made between the operated and fellow unoperated eyes, pre, and postoperatively. The assessment was made for changes in the radius of axial curvature on major meridians at 3 and 3.5 mm from the optical corneal center in the mid-peripheral zone. Astigmatism changes of the anterior and posterior corneal surface were calculated using vector analysis software (astigMATIC®). ANOVA model was used to examine the interaction between age or central corneal thickness and postoperative changes in anterior and posterior surface corneal astigmatism. Results In the intervention group, changes in anterior and posterior corneal surface astigmatism were statistically significant, with a mean increase of 0.59Dx92 and 0.08Dx91, respectively. In the mid-peripheral corneal zone, there is an increase in the radius of anterior corneal axial curvature more evident nasally 3.5 mm from the corneal center on the horizontal meridian, with corresponding decrease superiorly and inferiorly at 3 and 3.5 mm from the corneal center on the vertical meridian. Discussion The changes in total astigmatism of the operated eyes are mainly attributed to the anterior corneal surface. These changes are associated with flattening in the 180 meridian of the cornea, leading to a shift to “with-the-rule” astigmatism.

Comparison of short‐term clinical outcomes between sutured scleral fixation and modified Yamane sutureless scleral fixation

Aims/Purpose: To compare and investigate the short‐term clinical outcomes between 10‐0 polypropylene sutured intraocular lens (IOL) scleral fixation and modified Yamane sutureless IOL scleral fixation in patients with IOL or crystalline les dislocation and aphakic state.Methods: From August 2012 to May 2022, medical records were retrospectively analysed for 43 patients with sutured scleral fixation and 40 patients with sutureless scleral fixation. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), total astigmatism, IOL astigmatism, refractive error, corneal endothelial cell density, surgical time and complications were compared before surgery, 1 week, 1 month and 3 months after surgery.Results: In the two groups, after 3 months of surgery, UCVA and BCVA improved compared to before surgery, but there was no significant difference between two groups. The absolute refractive error and total astigmatism for 1 week after surgery and IOL astigmatism for 1 week and 1 month after surgery were significantly lower in sutureless fixation group. There was no significant difference in post‐operative corneal endothelial cell density changes between two groups, and total surgical time and IOL fixation time were measured significantly lower in sutureless fixation group.Conclusions: Although modified Yamane sutureless IOL scleral fixation did not show significant improvement in visual acuity compared with conventional sutured IOL scleral fixation, sutureless fixation provided better stability of IOL in the early stages after surgery and short in the surgical time. So it can be an effective alternative to conventional sutured scleral fixation in patients with IOL or crystalline lens dislocation and aphakic state.

Results of surgical treatment of children with lens subluxation

AIM: To assess the effectiveness of the surgical treatment of patients with lens subluxation, who were under 18 years old.&#x0D; MATERIAL AND METHODS: This study presented an analysis of the results of surgical treatment of eight patients with lens subluxation. The operations were performed in the Department of Ophthalmology of the State Healthcare Institution of Healthcare MCMC “Bonum,” carried out in 2020–2022. The inclusion criteria were as follows: age under 18 years, Marfan-like phenotype, stages 2–4 subluxation, absence of retinal changes and other eye pathologies, and surgical treatment performed in 2020–2022. The mean age at the detection of lens subluxation was 3.9±2.0 years, and the age during primary surgery was 5.4±1.9 years. All patients underwent phacoaspiration of the subluxated lens with anterior vitrectomy, simultaneous implantation, and sclerocorneal fixation of the intraocular lens by the same surgeon using the same equipment and consumables.&#x0D; RESULTS: The ophthalmological status was mainly assessed, and a statistical difference (p 0.05) was found between pre- and postoperative indicators. Before surgery, the maximum corrected visual acuity was 0.15±0.12 (min 0.02; max 0.5); spherical equivalent, 6.8±4.7 (min -15; max +16); total astigmatism value, 3.25±1.15 (min, 1; max, 6.5); and corneal astigmatism, 2.4±0.9 (min, 1; max, 3.9). After the surgical treatment, the maximum corrected visual acuity was 0.53±0.31 (min, 0.05; max, 0.9); spherical equivalent, −0.6±1.71 D (min −3.5; max +3); total astigmatism, -1.63±0.75 D (min, -0.25; max, −2.75); corneal astigmatism, 2.4±0.7 D (min 1; max 3.5). All operations were performed without complications. The postoperative period in patients was regarded as unreactive.&#x0D; CONCLUSION: The results show that sclerocorneal fixation allows for reliable and safe fixation of intraocular lenses without capsule support. A statistically significant increase in visual acuity was found after surgery; however, for optimal functional results in the postoperative period, refractive errors and pleoptic treatment must be controlled.

Children with high astigmatism: tomographic and refractive characteristics and the ability of current indices to rule out keratoconus

PurposeTo assess corneal tomographic, topographic, and refractive changes in children with high astigmatism and their ability to exclude keratoconus. MethodsIn this longitudinal observational study, the medical records of children with high regular cylindrical refraction of ≥3.50 D referred to the Hospital for Sick Children, Toronto, to exclude keratoconus between January 2009 and June 2020 were reviewed retrospectively. Corneal tomography records (Scheimpflug imaging) were reviewed for subjects with total astigmatism of ≥ +3.50 D by retinoscopy. Children with abnormal anterior segment examination and/or other risk factors for corneal disease or ectasia and those with unreliable corneal tomography were excluded. Baseline demographic, longitudinal tomographic, topographic, and refractive data were analyzed. ResultsA total of 67 eyes of 37 children (mean age, 9.1 ± 3.5 years) were included. Mean cylindrical refraction at presentation was 5.10 ± 1.30 D. Mean follow-up was 2.3 ± 1.8 years. Twenty-nine eyes had Kmax ≥47.20 D at baseline, with no change at last follow-up. Ksteep, Kmax, and thinnest pachymetry were 46.44 ± 2.33 D, 47.06 ± 2.57 D, and 525.86 ± 35.45 μm, respectively, at baseline compared with 46.40 ± 2.28 D, 46.98 ± 2.40 D, and 527.61 ± 37.67 μm at last follow-up (P > 0.05). All eyes were predicted as not having keratoconus using inferior-superior dioptric asymmetry ratio (I-S ratio), and the keratometry, inferior-superior, and astigmatism index (KISA%), which also incorporates skew percentage. The other tomographic indices predicted keratoconus or subclinical keratoconus in at least 22.4% of eyes. All parameters did not significantly change during follow-up. ConclusionsIn the absence of other risk factors for keratoconus, children with high regular astigmatism demonstrated clinical and tomographic stability over time. Based on our results, we recommend that I-S ratio and KISA% be primarily used when monitoring normal children with high astigmatism to rule out keratoconus-related changes.

Effects of atropine 0.01% on refractive errors in children with myopia

BackgroundLittle is known about changes in astigmatism during atropine treatment. We aimed to explore the effects of atropine 0.01% eye drops on both spherical and cylindrical refractive errors in myopic children. MethodsChildren aged 6–14 years with myopia ≥ −6.00 D and < −0.50 D, and total astigmatism > −2.00 D in at least one eye were enrolled. Subjects were randomised either to receive atropine 0.01% once nightly with single-vision lenses or simply to wear single-vision lenses and were followed up at 3-month intervals. Cycloplegic refraction and axial length were measured. The magnitude and direction of total astigmatism (TA), corneal astigmatism (CA), and residual astigmatism (RA) were evaluated. ResultsOverall, 119 eyes (69 eyes in the atropine group and 50 eyes in the control group) were included in the final analyses after 9 months. Atropine-treated eyes showed significantly less progression of myopia than did control eyes (spherical equivalent: −0.35 ± 0.33 vs. −0.56 ± 0.49 D, p = 0.001; axial length: 0.20 ± 0.19 vs. 0.33 ± 0.19 mm, p < 0.001). Compared with control eyes (−0.04 ± 0.23 D), a significant increase in TA was observed in the atropine-treated eyes (−0.14 ± 0.29 D); this was mainly attributed to the increase in CA (−0.17 ± 0.26 D) rather than the minor decrease in RA (0.02 ± 0.32 D). ConclusionsAtropine 0.01% was effective in preventing myopia progression, whereas 9 months of atropine treatment resulted in a clinically small, but statistically significant increase in TA in myopic Chinese children.

Comparison of Short-term Clinical Outcomes between Sutured Scleral Fixation and Modified Yamane Sutureless Scleral Fixation

Purpose: To compare and investigate the short-term clinical outcomes between 10-0 polypropylene sutured intraocular lens (IOL) scleral fixation and modified Yamane sutureless IOL scleral fixation in patients with IOL or crystalline les dislocation and aphakic state.Methods: From August 2012 to May 2022, medical records were retrospectively analyzed for 43 patients with sutured scleral fixation and 40 patients with sutureless scleral fixation. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), total astigmatism, IOL astigmatism, refractive error, corneal endothelial cell density, surgical time and complications were compared before surgery, 1 week, 1 month, and 3 months after surgery.Results: In the two groups, after 3 months of surgery, UCVA and BCVA improved compared to before surgery, but there was no significant difference between two groups. The absolute refractive error and total astigmatism for one week after surgery and IOL astigmatism for one week and one month after surgery were significantly lower in sutureless fixation group. There was no significant difference in postoperative corneal endothelial cell density changes between two groups, and total surgical time and IOL fixation time were measured significantly lower in sutureless fixation group.Conclusions: Although modified Yamane sutureless IOL scleral fixation did not show significant improvement in visual acuity compared with conventional sutured IOL scleral fixation, sutureless fixation provided better stability of IOL in the early stages after surgery and short in the surgical time. So it can be an effective alternative to conventional sutured scleral fixation in patients with IOL or crystalline lens dislocation and aphakic state.

Characteristics of full compensation and its association with total astigmatism: A cross-sectional study.

To evaluate the characteristics of full compensation and its association with the prevalence of total astigmatism (TA), and to analyze the effects of TA on uncorrected distance visual acuity (UDVA). With random cluster sampling based on a school-based cross-sectional design, children aged 4 to 18 years were recruited in September 2020, Shandong Province, China. TA, anterior corneal astigmatism (ACA), and ocular residual astigmatism (ORA) were converted to vectorial components (J0, J45), followed by an assessment of the compensatory effect of ACA by ORA. Astigmatism was defined as a cylinder that was better than or equal to 0.75 diopters (D). Logistic regression analysis was used to assess the related factors for children with full compensation, and the generalized linear model was used to assess the influence of TA on UDVA. Out of 4,494 eligible children, data of 4,145 children (92.3%, 9.23 ± 3.15 years, 50.4% boys) were included in the statistical analysis. The prevalence of TA (27.9%) increased significantly with age (Ptrend < 0.001). The distribution of full compensation in J0 and J45 components were similar (22.1% and 25.6%, respectively), which decreased with age (Ptrend < 0.001). The closer the refractive status was to emmetropization, the higher the proportion of full compensation and the lower the prevalence of TA were. Shorter axial length (J0: Odds Ratio (OR) = 0.76, 95% confidence interval (CI): 0.61 to 0.94, P = 0.010), better UDVA (J0: OR = 0.37, 95% CI: 0.21 to 0.65, P < 0.001; J45: OR = 0.34, 95% CI: 0.20 to 0.59, P < 0.001), and longer average corneal curvature radius (J0: OR = 3.72, 95% CI: 2.18 to 6.34, P < 0.001; J45: OR = 2.82, 95% CI: 1.67 to 4.76, P < 0.001) were associated with full compensation. Higher TA was associated with a worse UDVA (β = 0.03, 95% CI: 0.02 to 0.04, P < 0.001). The prevalence of TA gradually increased with age, and showed a U-shaped distribution with increased refraction. Full compensation was associated with smaller TA and better UDVA. This indicated that considering the compensatory effect of ORA is vital for astigmatism correction in clinical work, which may improve the visual quality.

Measurements of Anterior and Posterior Corneal Curvatures with OCT and Scheimpflug Biometers in Patients with Low Total Corneal Astigmatism.

Background: Posterior keratometry measurements are evolving features of the optical biometers. The differences between devices have bigger impact for the low astigmatism values. The majority of adults present the corneal astigmatism below 1.5 D. Objectives: To compare the total corneal astigmatism measured with two different technologies in cataract patients with corneal astigmatism below 1.5 D. Material and Methods: Three automated exams were performed on each of the two devices: swept-source optical coherence tomography (SS-OCT) and Scheimpflug biometers. The anterior and total corneal astigmatism and power were analysed. Statistical comparisons were performed for within-subject standard deviation, repeatability, Bland−Altman and vector analysis. Results: Twenty-nine eyes of twenty-seven patients were included. The limits of agreement between anterior and total corneal astigmatism were narrower for the SS-OCT than for the Scheimpflug biometer (−0.16 to 0.29 D and −0.40 to 0.39 D, respectively). The >0.5 D difference between SS-OCT and Scheimpflug total astigmatism was noticed in 5 (17%) of cases. The difference between mean total keratometric power for both devices was statistically significant (0.2 D, p < 0.001). SS-OCT total corneal flat measurements had worse repeatability than Scheimpflug (p = 0.007). Conclusions: For the corneal astigmatism <1.5 D, the difference between anterior and total corneal astigmatism measured with SS-OCT was clinically not significant. The mean anterior and total keratometry values obtained with Scheimpflug and SS-OCT biometers are not interchangeable.

Toric trans-scleral plugs IOL to correct aphakia with significant corneal astigmatism.

To describe the use of toric trans-plugs IOL to correct aphakia with significant corneal astigmatism. Case report and literature review. A 62-year-old man with an history of aphakia in his left eye after a traumatic cataract extraction and significant corneal astigmatism was referred to our clinic. Surgery plan was cataract remnants removal and secondary IOL implantation of toric sutureless trans-scleral plugs fixated IOL (FIL SSF, Soleko, Italy). The postoperative course was uneventful. At 12 months, the IOL was well-centered and the optic alignment remained stable with minimal total astigmatism. The e uncorrected distance visual acuity (UDVA) was 20/25 Snellen while correct distance visual acuity (CDVA) was 20/20 with a manifest refraction of -0.25-50 40° D; the patient was satisfied by the visual outcome. This novel toric trans-scleral plug fixated lens provides valuable outcomes also for astigmatic correction for a comprehensive correction of the aphakia in patients with poor zonular support and high expectations for postoperative visual quality.

The 10,000 Eyes Study: Analysis of Keratometry, Abulafia-Koch regression transformation, and Biometric Eye Parameters Obtained With Swept-Source Optical Coherence Tomography

To analyze Abulafia-Koch regression (AKRT), anterior and posterior astigmatism (K and TK), and evaluate biometry data in a large population. Retrospective cross-sectional study. This multicenter (2 tertiary care centers) study analyzed datasets acquired between 2017 and 2020. Axial length (AL), corneal front and back radii (including meridians for K and TK conversion), horizontal corneal diameter, anterior chamber depth, lens thickness, and central corneal thickness were measured using telecentric keratometry and swept-source optical coherence tomography-based biometry (IOLMaster 700; Carl Zeiss Meditec AG). Cooke-modified axial length (CMAL) and AKRT were calculated. Difference vectors between K and TK astigmatism and between AKRT and TK astigmatism were compared. A total of 10,300 eyes from 6388 patients were assessed. Difference vectors for K and TK were significantly smaller than for AKRT and TK. K measurement showed a configuration of 51.49% of with-the-rule astigmatism and 30.51% against-the-rule astigmatism, TK measurement showed a configuration of 41.60% of with-the-rule astigmatism and 40.21% against-the-rule astigmatism. Mean total astigmatism was -0.94 ± 0.74 dpt. Mean values for AL and CMAL were 23.70 ± 1.39 mm and 23.70 ± 1.34 mm, respectively. Anterior chamber depth, lens thickness, horizontal corneal diameter, AL, and age were all correlated with each other. Astigmatism analysis showed less difference between K and TK than between AKRT and TK. There were significantly fewer eyes with with-the-rule astigmatism and more eyes with against-the-rule astigmatism configuration in TK-derived than in K-derived keratometry. The study provides data on gender and generational differences in biometry. Significant intersexual differences in AL and CMAL were observed, with CMAL providing lower standard deviation compared with AL.

The Utility of Peripheral Vitrectomy Featuring Scleral Indentation during Scleral Fixation of Intraocular Lenses

Purpose: We evaluated the utility of peripheral vitrectomy featuring scleral indentation; we compared a group who underwent peripheral vitrectomy to a control group for whom vitrectomy was combined with scleral fixation of intraocular lenses (IOLs) in patients exhibiting IOL dislocations.Methods: From January 2018 to December 2020, 20 eyes of patients evidencing IOL dislocations that underwent total vitrectomy, IOL removal, and IOL scleral fixation were evaluated; peripheral vitrectomy with scleral indentation was performed in 10 patients. All operations were performed by the same surgeon. We excluded patients with follow-up periods less than 6 months, those with a history of retinal and/or glaucoma surgery, and patients with retinal abnormalities or glaucoma that might significantly compromise visual acuity. The postoperative best-corrected visual acuity, intraocular pressure, astigmatism changes, and complications were retrieved from the medical records.Results: Six months after surgery, the best corrected visual acuity was 0.95 (the Snellen measure) in the group who underwent peripheral vitrectomy featuring scleral indentation, and 0.60 in the control group (p = 0.029). The total astigmatism values were 0.48 diopter in the former and 2.80 diopter in the latter group; the difference was significant (p &lt; 0.001).Conclusions: In patients with IOL dislocations who underwent vitrectomy combined with IOL scleral fixation, improvements in visual acuity were further enhanced when peripheral vitrectomy was combined with scleral indentation. Complete removal of the peripheral vitreous may stabilize IOL positioning by the remnant vitreous.

Corneal higher-order aberration changes after accelerated cross-linking for keratoconus

AimTo evaluate changes in corneal higher-order aberrations (HOAs) following epithelium-off accelerated corneal cross-linking (A-CXL) and to explore the impact on visual acuity.MethodsIn this retrospective case series, 32 eyes of 24 patients with keratoconus (KC) underwent A-CXL. Treatment was delivered at 10 mW/cm2 for 9 min with a total dose of 5.4 J/cm2. The following anterior corneal HOAs: total corneal HOAs, trefoil, secondary trefoil, coma, secondary coma, secondary astigmatism and spherical aberrations were analysed using the Scheimpflug-Placido Sirius (CSO, Italy) corneal topographer at baseline and 12 months following treatment. Multivariate analysis was used to evaluate the independent effect of HOA subtypes on changes in uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA).ResultsAt one year post CXL, UDVA and CDVA were significantly improved, -0.13 ± 0.19 LogMAR (P = 0.0005) and -0.08 ± .0.11 LogMAR (P = 0.0003), respectively. The mean preoperative trefoil, secondary trefoil, secondary coma and secondary astigmatism were 0.95 ± 0.46; µm, 0.20 ± 0.11; µm, 0.29 ± 0.19; µm and 0.42 ± 0.17 µm, respectively. At one year, the mean values decreased significantly to 0.77 ± 0.47 µm, 0.15 ± 0.11 µm, 0.25 ± 0.18 µm and 0.34 ± 0.18 µm, respectively (P < 0.05, for all). No independent relationship between any HOA changes and change in UDVA was observed. A reduction in secondary coma aberration was associated with a change in CDVA (95% CI 0.01–1.34, P = 0.048; β = 0.67).ConclusionA 9-min protocol of Accelerated corneal cross-linking is an effective treatment in improving corneal HOAs at 12 months follow up, in eyes with progressive keratoconus at one year follow-up. A change in secondary coma had a statistically significant and independent effect on CDVA.

Prevalence and inconformity of refractive errors and ocular biometry of 3573 medical university freshman students for 4 consecutive years.

To evaluate the prevalence of refractive errors and ocular biometry in 3573 freshman students at Tianjin Medical University for 4 consecutive years. In this university-based, cross-sectional study, comprising 3573 students, visual acuity (VA), slit-lamp examination, non-cycloplegic auto-refraction, and ocular biometry were recorded. The prevalence of myopia increased annually, from 2017 to 2020 were 93.5%, 94.5%, 95.9%, and 96.2%, respectively (P=0.03), and the prevalence of high myopia was 25.7%, 26.9%, 28.6%, and 28.6%, respectively. Males tended to have a higher percentage of total astigmatism than females, with astigmatism ≥0.75 and ≥1.0 D criteria. The percentage of with-the-rule astigmatism, against-the-rule astigmatism, and oblique astigmatism was 90.3%, 5.8%, and 3.9%, respectively, with astigmatism ≥1.00 D criteria. The mean spherical equivalent, axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), corneal radius (CR), and lens position (LP) were 4.37±2.52 D, 25.28±1.24 mm, 539.49±34.98 µm, 3.31±0.34 mm, 3.47±0.21 mm, 7.8±0.28 mm, and 5.04±0.32 mm, respectively. With diopter increase in myopia, the AL became longer, CR became steeper, ACD became deeper, LT became thinner, and LP became more posterior (all P<0.01). Females had a shorter AL, thinner CCT, smaller CR, shallower ACD, thicker lens, and more anterior LP than males (P<0.01). The 64% of high myopia had AL≥26 mm, meanwhile, 5.8% mild myopia and 21.1% moderate myopia had AL≥26 mm. With AL≥26 mm, mild and moderate myopia compared to high myopia, AL was shorter (26.51±0.46 vs 26.87±0.70 mm), CR was larger (8.10±0.3 vs 7.85±0.23 mm) and LT was thinner (3.39±0.19 vs 3.45±0.19 mm, P<0.001). The prevalence of myopia and high myopia is significantly high in freshman students. The majority of astigmatism is with-the-rule. Inconformity of refractive errors and ocular biometry existed in some students. Attention should be paid to the ocular biometry of myopia.

Differential compensatory role of internal astigmatism in school children and adults: The Hong Kong Children Eye Study.

To compare the prevalence of refractive (RA), corneal (CA), and internal astigmatism (IA) in Hong Kong children and adults and evaluate the role of IA in compensating for total astigmatism and its relations to myopic traits. The Hong Kong Children Eye Study is a population-based cross-sectional study. Totally 3704 school children (mean age 7.5 ± 1.0 years) and 5577 adults (mean age 41.1 ± 7.5 years), who were their parents, were recruited. Cycloplegic and non-cycloplegic refractive cylinders were obtained from children and adults, respectively. Spearman correlation was applied to detect associations between astigmatism, ocular biometrics, refraction, and lens power. Astigmatism compensation factor (CF) was derived from the power vector analysis J0 and J45. The prevalence of RA (≤-1.0 D), CA (≥+1.0 D) and IA (≥+1.0 D) was 21.9%, 63.9%, and 9.9% in children, and 30.9%, 39.5%, and 23.7% in adults respectively. The mean RA, CA and IA values in children and adults were -0.69 ± 0.66 D, +1.14 ± 0.61 D, +0.62 ± 0.32 D, and -0.80 ± 0.74 D, +0.97 ± 0.69 D, and +0.76 ± 0.43 D, respectively. In adults and children, IA was negatively correlated with axial length (p < 0.0001), but positively correlated with spherical values and equivalent (p < 0.0001), suggesting an association of astigmatism with myopic traits. A greater proportion of children exhibited compensation by IA than adults in J0 (86.6% vs. 66.0%, p < 0.0001) and J45 components (55.5% vs. 41.7%, p < 0.0001). Chinese children in Hong Kong exhibit a higher prevalence of RA and CA than in other cities. Children displayed a greater compensation by IA than adults, suggesting an age-related attenuation of IA compensation. IA is associated with myopic traits.

Mediators of the Effect of Corneal Cross-Linking on Visual Acuity for Fungal Ulcers: A Prespecified Secondary Analysis From the Cross-Linking-Assisted Infection Reduction Trial.

The purpose of this study was to determine whether astigmatism or corneal scarring is mediating the reduced visual acuity among patients with fungal keratitis randomized to corneal cross-linking (CXL). This was a prespecified exploratory outcome from an outcome-masked, 2 × 2 factorial design, randomized controlled clinical trial. Consecutive patients presented with moderate vision loss from a smear-positive fungal ulcer at Aravind Eye Hospital, Madurai, India. Study eyes were randomized to one of 4 treatment combinations using an adaptive randomization protocol. The treatment arms included (1) topical natamycin 5% alone, (2) topical natamycin 5% plus CXL, (3) topical amphotericin B 0.15% alone, and (4) topical amphotericin 0.15% plus CXL. Best spectacle-corrected visual acuity (BSCVA), contact lens over-refraction, and scar size and depth as measured by a masked study ophthalmologist using a standardized protocol were recorded at 3 months. Pentacam Scheimpflug imaging was also obtained at 3 months. BSCVA and contact lens over-refraction, infiltrate and/or scar size and depth, total astigmatism of the front and back of the cornea, total lower-order and higher-order aberrations of the anterior and posterior cornea, and total densitometry of the anterior, central, and posterior stroma were recorded. We performed a mediation analysis looking at the proportion of the effect of CXL on BSCVA that was mediated through scar size, scar depth, astigmatism and density. BSCVA at 3 months was available for 99 of 111 patients (89%) who had a mean of 0.82-LogMAR (SD 0.68). Three-month infiltrate and/or scar size ( P < 0.001), depth ( P < 0.001), and densitometry ( P = 0.001) were statistically significant predictors of 3-month BSCVA. Astigmatism seemed to mediate 23% of the effect of CXL on BSCVA, whereas scar size mediated 23%, scar depth 17%, and densitometry 7%. Corneal scarring and astigmatism are mediators of worse visual acuity after cross-linking in fungal keratitis. Corneal densitometry may be a helpful cornea-specific variable for clinicians and researchers in determining the effect of corneal scarring on visual acuity in specific patients and as an objective study outcome. NCT02570321.