Posterior Astigmatism Research Articles

Aphakia treatment with sutureless scleral fixation or retropupillary iris-claw intraocular lens implantation: visual acuity, anterior segment and keratometry outcomes

PurposeEvaluation of anterior segment parameters using the Scheimpflug corneal topography 1 year after surgery in patients who underwent sutureless scleral fixation intraocular lens (SFIOL) implantation using the modified Yamane technique and retropupillary iris-claw intraocular lens (RPIOL) implantation.MethodsA total of 60 eyes from 57 patients who underwent sutureless SFIOL implantation and 57 eyes from 52 patients who underwent RPIOL implantation were included. Anterior chamber depth (ACD), anterior chamber angle (ACA), anterior chamber volume (ACV), anterior–posterior corneal astigmatism, and keratometric values were assessed using the Scheimpflug corneal topography (Pentacam HR, Germany).ResultsThere was no statistically significant difference in postoperative UCVA and BCVA between the sutureless SFIOL and the RPIOL group (p = 0.236, p = 0.293, respectively). While there was no statistically significant difference in postoperative IOP between the two groups (p = 0.223), a statistically significant decrease in IOP was observed in both groups (p < 0.001). While there was no statistical difference between the sutureless SFIOL group and the RPIOL group in terms of spherical value (p = 0.441) and spherical equivalence (p = 0.237), there was a statistically significant difference in cylindrical value (p < 0.001). While there was a statistical difference in anterior astigmatism (p < 0.001), there was no statistical difference in posterior astigmatism (p = 0.405). There was no statistical difference in terms of ACV, ACD, and ACA between the sutureless SFIOL and the RPIOL group (p = 0.812, p = 0.770, p = 0.401, respectively).ConclusionIn this study, although there was a statistical difference in cylindrical value and anterior corneal astigmatism between the sutureless SFIOL and RPIOL groups, vision was not affected. According to this study, sutureless SFIOL and RPIOL are two successful methods in terms of visual acuity, anterior segment, and keratometry outcomes in aphakic patients after phacoemulsification.

Keratometry Changes Between Year One to Seven After Corneal Cross-Linking in Patients With Keratoconus.

We evaluated the timing at and extent to which midterm to long-term keratometric changes can occur in year 1 to 7 after corneal collagen cross-linking (CXL) in patients with keratoconus. We conducted a subgroup analysis of a retrospective cohort study of all consecutive patients who underwent CXL at our cornea center between 2007 and 2011. The inclusion criteria comprised CXL according to the Dresden protocol and a full set of keratometry parameters collected by Scheimpflug tomography preoperatively and at year 1, 3, 5, and 7 after CXL. In addition, best-corrected visual acuity was evaluated. Sixty-three eyes of 47 patients were enrolled. Mean age was 25.46 years ±7.39 years (80.9% male patients). All relevant keratometric parameters showed significant improvement at year 1 after CXL (except for posterior astigmatism). According to mixed-effects model analysis, they all showed further significant change at different points in time between year 1, 3, 5, and 7 (except for K1). In addition, best-corrected visual acuity improved statistically significant between year 1, 3, 5, and 7. Suspected disease progression was noted in 22.2% of patients, mostly between year 1 and 3 after CXL. After initial improvement 1 year after CXL, keratometric and functional parameters were stable until year 5 after CXL in most cases; further improvement can take place even after up to 7 years post-CXL. By contrast, in case of disease progression, changes seem to occur already between year 1 and 3 after CXL.

Change in posterior astigmatism with degree of decentring graft in patients with descemet stripping automated endothelial keratoplasty

Aims/Purpose: Aligning the center of grafts in patients with Descemet Stripping Automated Endothelial Keratoplasty (DSAEK) is difficult but important process. We investigated how the graft centring affected posterior astigmatism in patients.Methods: This study analysed 63 patients (63 eyes) who received DSAEK. Postoperative posterior astigmatism of patients was measured using pentacam, and the decentring of the graft was measured by using the distance between the patient's optic centre and the centre of the graft. Correlation analysis was performed on the relationship between graft decentring and posterior astigmatism. In addition, the spherical aberration of the cornea before and after surgery was analysed and investigated.Results: The average posterior astigmatism of the patients before surgery was 1.70 ± 2.25, and the average posterior astigmatism was 0.66D ± 0.43, confirming a decrease in posterior astigmatism after surgery (p &lt; 0.05). The mean decentring of graft was 0.45 ± 0.33 mm. Preoperative spherical aberration was 0.192 ± 0.53 and postoperative spherical aberration was 0.044 ± 0.37, and these differences were not statistically significant (p &gt; 0.05). Analysis of the relationship between graft decentring and postoperative posterior astigmatism showed no statistically significant correlation (p &gt; 0.05).Conclusions: In this study, no significant correlation was found between centring of the graft and posterior astigmatism after surgery. However, centring of the graft in DSAEK plays an important role in graft survival and postoperative prognosis, surgeons should pay attention to centring well during surgery.

Accelerated Corneal Crosslinking for Treatment of Keratoconus in Children and Adolescents under 18 Years of Age.

To evaluate the efficacy of accelerated (9 mW/cm2, 10 min) epithelium-off (epi-off) corneal crosslinking (A-CXL) in keratoconus (KC) patients < 18 years of age. Our retrospective study included 41eyes (25 male and 5 female patients, mean age 15.3 ± 1.2 years) who underwent A-CXL (9 mW/cm2, 10 min) because of progressive KC or critical KC at first presentation or asymmetrical finding in the partner eye. Outcome measures were best-corrected visual acuity (BCVA) and tomography readings (Pentacam HR, Oculus, Wetzlar, Germany), evaluated 2 years, 1 year, 6 months preoperatively, prior to surgery (pre-CXL) and 6 weeks, 6 months, 1 year, 2 years, > 2 years postoperatively (post-CXL). The demarcation line was assessed by anterior segment optical coherence tomography (SS-1000 and CASIA 2, Tomey, Nagoya, Japan). Total deviation value increased statistically significantly 6 months pre-CXL to pre-CXL. Anterior steep, flat, and mean keratometry values showed a statistically significant increase 6 weeks post-CXL (p < 0.05), followed by a significant decrease until 2 years post-CXL for steep and mean keratometry. Kmax increased 6 weeks post-CXL without statistical significance and decreased significantly even > 2 years post-CXL (p < 0.0001). Posterior keratometry as well as anterior and posterior astigmatism did not show any significant changes post-CXL. Thinnest and apical pachymetry decreased significantly until 6 months post-CXL (p < 0.05) and remained stable > 2 years post-CXL (p > 0.05). BCVA decreased 6 weeks post-CXL but improved significantly > 2 years post-CXL (p = 0.003). The demarcation line reached an average depth of 52.1%. Epi-off A-CXL stabilizes KC progression in patients < 18 years even > 2 years postoperatively and leads to a deep demarcation line. A "pseudoprogression" is observed up to the 6-week follow-up, which is not indicative of the long-term results.

Corneal cross-linking in patients with keratoconus: up to 13years of follow-up.

To evaluate long-term safety and efficacy of corneal collagen cross-linking (CXL) in patients with keratoconus up to 13years. In this mono-centre exploratory study, we included all consecutive patients who underwent CXL in our cornea centre from 01/01/2007 to 12/30/2011 and met the inclusion criteria. CXL was performed in all patients according to the Dresden protocol. Evaluation included best-corrected visual acuity (BCVA), topographic keratometry by Scheimpflug corneal tomography and endothelial cell count (ECC). Follow-up measurements were taken up to 13years after treatment were compared with baseline values. The study enrolled 168 eyes. The mean age of our patients was 26.3years ± 7.8years. A complete topographic dataset was available 1year postoperatively for 142 eyes, 5years postoperatively for 105 eyes, 10years postoperatively for 61 eyes and 13years postoperatively for 9 eyes. BCVA increased statistically significant after 1year, 5years and 10years and non-significantly after 13years. All keratometric parameters with exception of posterior astigmatism showed a statistically significant decrease after 1year, 5years and 10years. After 13years, the decrease was statistically significant only in Kmax, K2 and thinnest cornea. No significant changes in ECC were detected. Three eyes received Re-CXL, none of the eyes received penetrating keratoplasty and no infections occurred in this cohort. CXL can slow down or even stop the progression of keratoconus in the majority of cases. The effect is long-lasting with excellent safety.

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.

Surgical Rehabilitation of a Posttraumatic Iris Cyst, Cataract and Astigmatism Patient. Clinical Case

Injuries cause serious disturbance of the form and function of the organ of vision due to the damage and accompanying or remote complications and therefore have a high proportion to the structure of low vision, blindness and disability. One of the complications of penetrating wounds of the eye is iris cysts. Iris cyst can increase and cause pupillary block, secondary glaucoma, uveitis, corneal dystrophy, and therefore it requires surgical intervention. The goal of surgical treatment of an iris cyst is to ensure complete removal of the cyst.Objective: to estimate the clinical and functional results of treatment in a posttraumatic iris cyst, posterior subcapsular cataract and myopic astigmatism patient.Patient and methods. Patient B., 49 years old with posttraumatic retention iris cyst, posterior subcapsular cataract, compound myopic high astigmatism was examined. To determine the tactics of surgical treatment of the patient, a complex of General ophthalmology was perfomed (visometry, IOP measurement, autorefractometry, biomicroscopy, ophthalmoscopy), as well as special (B-scanning, optical coherence tomography of the retina) research methods. The follow-up period was 1 year.Results and discussion. To improve visual functions and prevent the development of secondary glaucoma, the patient was offered surgery - excision of the iris cyst and cataract phacoemulsification with toric intraocular lens. Simultaneous carrying out of two stages of the operation reduced the risks of postoperative complications and shorten the rehabilitation period.Conclusion. Positive optical and therapeutic effects were achieved as a result of the surgical treatment 44 years after an open eye injury: the eye is calm, the iris cyst is not detected, visual acuity has increased. The postoperative period showed the saving the stable and high visual and functional result with no recurrence of the iris cyst.

Comparing Changes in Corneal Astigmatism Using Scheimpflug Camera after Epiblepharon Correction Surgery

Purpose: To evaluate the changes in corneal astigmatism before and after epiblepharon correction surgery with a Scheimpflug camera.Methods: From April, 2019, to June, 2020, 48 eyes of 24 patients underwent epiblepharon correction surgery. The patients were divided into two subgroups by age and their best corrected visual acuity (BCVA) and corneal anterior and posterior astigmatism were compared before and after correction surgery.Results: There was no difference in BCVA after the correction surgery. To assess the changes in the keratometric value and astigmatism after epiblepharon surgery, a Scheimpflug camera was used. The anterior flat and mean keratometry changed from 42.10 ± 1.46 to 42.43 ± 1.10 D (p = 0.035) and from 42.97 ± 1.26 to 43.21 ± 1.15 D (p = 0.012), respectively, while the posterior corneal astigmatism changed from 0.44 ± 0.31 to 0.35 ± 0.17 D (p = 0.047). There were no significant changes in steep keratometry (p = 0.191) or anterior corneal astigmatism (p = 0.126).Conclusions: There were significant changes after epiblepharon correction surgery in anterior keratometry reading and posterior corneal astigmatism.

Surgically induced astigmatism and posterior corneal curvature changes following phacoemulsification.

Purpose:To primarily compare surgically induced astigmatism (SIA), total and posterior corneal curvature, pachymetry, and their stabilization after 2.2 and 2.8 mm clear corneal incision in phacoemulsification.Methods:A randomized, prospective interventional study of 130 patients (130 eyes) of either sex having senile cataract (>40 years) divided randomly into two groups. The patients underwent uncomplicated phacoemulsification surgery with foldable intraocular lens implantation using 2.2 mm (group 1) and 2.8 mm incisions (group 2). The patients were evaluated preoperatively and followed-up at first, third, and sixth weeks.Results:Mean SIA was less in group 1 at all the follow-up visits which was not statistically significant (P value – 0.507 (at week 1), 0.626 (at week 3), and 0.312 (at week 6). Mean SIA decreased from week 1 to week 6 in both the groups. Both the groups showed an increase in SIA with the increase in the hardness of cataract. Posterior keratometry (k1 and k2) showed statistically significant steepening in the first postoperative week, followed by gradual flattening which continued till the sixth week postoperatively. Posterior astigmatism increased in both the groups at week 1 (not statistically significant). Thereafter, it decreases and does not change significantly after 3 weeks. Pachymetry increased significantly (P value < 0.001 in both the groups) in the first week in both the groups and thereafter stabilizing at 3 weeks.Conclusion:Reducing the incision size does not result in any significant reduction in SIA. We observed that the posterior corneal curvature majorly stabilized by 3 weeks, but some stabilization continued till 6 weeks.

Delicate balance: the relationship between internal astigmatism and lens astigmatism

Background: Due to lack of equipment for directly measuring crystal morphology, there has been little research on lenticular astigmatism. The purpose of this study was to accurately explore the correlation between internal astigmatism and lens astigmatism in patients with ametropia. Methods: This is a cross-sectional study conducted in the Affiliated Hospital of North Sichuan Medical College, China, in September 2020. Diopter values (refractive astigmatism, RA) of patients with ametropia was recorded, and the corneal and lens biological parameters were measured by CASIA2 (corneal/anterior segment optical correlation tomography analyzer). Biometric parameters, including the total corneal astigmatism (total corneal astigmatism, TCA), anterior and posterior curvature radius of the lens (anterior curvature radius of the lens, ACL; posterior curvature radius of the lens, PCL), internal astigmatism (internal astigmatism, IA), anterior and posterior astigmatism of the lens (anterior astigmatism of the lens, AAL; posterior astigmatism of the lens, PAL) were measured. Grouping and comparisons were made according to gender and age. Results: In total, 151 participants (293 eyes) were included in the analysis. There were significant ( P&lt;0.05) differences in the IA ( Z=-2.194, P=0.028) according to gender, but not in the other parameters. By age group, there were statistically significant differences in the TCA ( H=10.609, P=0.005), IA ( F=3.722, P=0.025), and PAL ( H=8.254, P=0.016), but not in the others. The IA was positively correlated with the age ( r=0.155, P=0.008), RA ( r=0. 534, P&lt;0.001), AAL ( r=0.308, P&lt;0.001), and was negatively correlated with the TCA ( r=-0.244, P&lt;0.001). The regression equation between the IA and AAL was: Y (IA) =-0.626 +0.447 X (AAL). Conclusions: Internal astigmatism is mainly related to the anterior astigmatism of the lens, and the higher the anterior astigmatism of the lens, the higher the internal astigmatism; At the same time, internal astigmatism increases with age.

Accelerated versus Standard Corneal Cross-linking for Progressive Keratoconus in Syria.

PurposeTo compare the outcomes of accelerated versus standard corneal cross-linking for the treatment of progressive keratoconus.Methods In this retrospective comparative study, 63 eyes of 40 patients with progressive keratoconus were divided into two groups; 27 eyes in group one were treated with an accelerated protocol (10 mW/cm, 9 min) and 36 eyes in group two were treated with the standard method (3 mW/cm, 30 min). Visual acuity, refraction, corneal topography, corneal tomography, and anterior and posterior corneal higher-order aberrations (HOAs) were assessed preoperatively and 18–30 months postoperatively.ResultsThe LogMAR uncorrected and corrected distance visual acuity values were improved in both groups postoperatively. However, the improvement was significantly higher in group one (P 0.05, all). The flattening in the anterior keratometry readings, flat K, steep K, and average K were significantly higher in group two (P 0.001, all). The maximum anterior keratometry (AKf) values significantly decreased in both groups, whereas the maximum posterior keratometry (AKb) values increased. The reduction in the minimum corneal thickness (ThKmin) was significantly greater (36.49um) in group two, compared to 10.85um in group one. There was a significant increase in the posterior average keratometry, and a significant decrease in the posterior astigmatism, along 3 mm meridian in S-CXL (P = 0.03, P = 0.008, respectively), while the corresponding values showed no statistical significance in group one (P 0.05). The anterior corneal trefoil was significantly reduced in group one (P = 0.002), whereas anterior total HOAs and coma were significantly improved in group two (P 0.0014, all). The posterior corneal spherical aberration decreased significantly in group one (P = 0.02), while group two revealed significant reduction in the posterior trefoil values (P = 0.011). The change in the anterior maximum keratometry was significantly and positively correlated to the preoperative maximum keratometry in group two (P = 0.53, P = 0.003).ConclusionAn accelerated cross-linking protocol using 10 mW/cm for 9 min showed more visual improvement and less pachymetric reduction when compared to the standard protocol, however, anterior corneal flattening, posterior corneal steepening, and the change in the posterior astigmatism were significantly higher in the standard protocol; while corneal HOAs were improved in both protocols.

Delicate balance: the relationship between internal astigmatism and lens astigmatism

Background: Due to lack of equipment for directly measuring crystal morphology, there has been little research on crystal astigmatism. The purpose of this study was to accurately explore the correlation between internal astigmatism and lens astigmatism in patients with ametropia. Methods: This is a cross-sectional study conducted in the Affiliated Hospital of North Sichuan Medical College, China, in September 2020. Diopter values (refractive astigmatism, RA) of patients with ametropia was recorded, and the corneal and lens biological parameters were measured by CASIA2 (corneal/anterior segment optical correlation tomography analyzer). Biometric parameters, including the total corneal astigmatism (TCA), anterior and posterior curvature radius of the lens (ACL, PCL), internal astigmatism (IA), anterior and posterior astigmatism of the lens (AAL, PAL) were measured. Grouping and comparisons were made according to gender and age. Results: In total, 151 participants (293 eyes) were included in the analysis. There were significant (P&lt;0.05) differences in the IA (Z=-2.194, P=0.028) according to gender, but not in the other parameters. By age group, there were statistically significant differences in the TCA (H=10.609, P=0.005), IA (F=3.722, P=0.025), and PAL (H=8.254, P=0.016), but not in the others. The IA was positively correlated with the age (r=0.155, P=0.008), RA (r=0. 534, P&lt;0.001), AAL (r=0.308, P&lt;0.001), and was negatively correlated with the TCA (r=-0.244, P&lt;0.001). The regression equation between the IA and AAL was: Y (IA) =-0.626 +0.447X (AAL). Conclusions: There is a delicate balance between internal astigmatism and intraocular astigmatism. There were no significant differences in the other parameters except IA for different gender groups. For different ages, there are symbol differences in the TCA, IA and PAL, but not in the other parameters. In the analysis of IA with lens astigmatism, it was found that internal astigmatism was mainly related to AAL, but not to PAL.

Characteristics of corneal high-order aberrations in adolescents with mild to moderate myopia

BackgroundThis study investigated the characteristics of corneal higher-order aberrations (HOAs) of the anterior surface, posterior surface, and total cornea in adolescents with mild to moderate myopia.MethodsA total of 183 patients with myopia (183 eyes) aged 8 to 18 years were enrolled in this study. The axial length (AL) of the eyes was measured by an IOL-Master, and corneal curvatures (K-values) and HOAs were measured by a Pentacam anterior segment diagnostic analyzer.ResultsResults of this study showed that the anterior, posterior and total corneal horizontal coma Z31 were − 0.1249 ± 0.105 μm, 0.0009 ± 0.001 μm, and − 0.1331 ± 0.116 μm, respectively; the anterior, posterior and total corneal vertical coma Z3− 1 were − 0.0212 ± 0.164 μm, 0.0003 ± 0.043 μm, and − 0.0216 ± 0.168 μm, respectively; and spherical aberration (SA) Z40 values were 0.2244 ± 0.091 μm, 0.1437 ± 0.029 um, and 0.1889 ± 0.090 μm, respectively. Total corneal Z31 was statistically correlated with posterior corneal astigmatism (K2b − K1b) (p = 0.038). Total corneal Z3− 1 was correlated with anterior corneal astigmatism (K2f − K1f) (p = 0.027). Anterior, posterior, and total corneal Z40 were correlated with anterior and posterior corneal curvature (K1f, K2f, K1b, K2b) (p = 0.001). Posterior corneal Z40b was also significantly correlated with AL.ConclusionsIn adolescents with mild to moderate myopia, the posterior corneal surface shape may play a compensatory role in the balance of corneal aberrations, and the posterior corneal SA tended to become less negative as the AL increased. The corneal coma may also play a compensatory role in posterior corneal surface astigmatism, which was valuable for the treatment for improving visual quality. This conclusion still needs to be verified.

Evaluation of posterior and total corneal astigmatism with colour-LED topography.

To characterise the posterior and total corneal astigmatism using colour point-source light-emitting diodes (LED) topography. In a prospective case series 400 eyes from 400 patients were evaluated by colour-LED topography. Only eyes with normal topographies were considered. The following parameters were studied: magnitude and distribution of SimK and posterior corneal astigmatism, correlation between SimK and posterior corneal astigmatism, and differences in magnitude and axis between total and anterior corneal astigmatism. The mean SimK corneal astigmatism was 1.21 ± 0.94 D. The mean posterior corneal astigmatism was 0.37 ± 0.24 D. Posterior astigmatism was vertically oriented in 68% of eyes. Twenty-two percent of eyes showed a posterior corneal astigmatism ≥ 0.50 D. The correlation coefficients between SimK and posterior corneal astigmatism were: r2 = 0.066; p = 0.371 in WTR eyes, r2 = 0.112; p = 0.173 in ATR eyes and r2 = -0.019; p = 0.879 in oblique eyes. A difference between SimK and total corneal astigmatism ≥ 0.50 D was found in 7% of eyes. A difference in axis between SimK and total corneal astigmatism ≥ 10° was found in 24% of eyes. The percentage of eyes with posterior corneal astigmatism ≥ 0.50 D and the differences between anterior and total corneal astigmatism were higher than those previously reported in the literature. Therefore, this study supports the consideration of total corneal astigmatism magnitude and axis is mandatory for a precise surgical correction of astigmatism.

Analysis and Causation of All Inaccurate Outcomes After WaveLight Contoura LASIK with LYRA Protocol.

PurposeThis study analyzes every eye that had an outcome greater than 0.25D of sphere or astigmatism from planned goal after treatment with WaveLight Contoura with LYRA Protocol.MethodsThe study included 266 consecutive eyes treated with LASIK Contoura using the LYRA Protocol. All LASIK procedures were performed on the WaveLight EX500 excimer laser. Flaps were created with either the Alcon WaveLight FS200 femtosecond laser or the Moria M2 microkeratome. Eyes that were off by >0.25 diopters (D) sphere or cylinder from the targeted goal within 3 months after surgery were identified and analyzed for cause. Topographical, higher-order aberration, and epithelial maps were created.ResultsCauses for inaccurate outcomes were biomechanical corneal change from LASK flap creation (9.78% of total eyes), pre-operative epithelial compensation of corneal higher-order aberration (4.1% of total eyes), changes to lamellar corneal tension from laser ablation causing a hyperopic shift (1.9% of total eyes), epithelial thickening over the ablation area post-operatively causing a refractive change (1.5% of total eyes), and posterior astigmatism (0.75%).ConclusionThe causes of the majority of inaccurate outcomes have not been properly defined and must be incorporated into further improving outcomes. Current and planned advances in technology do not address the majority of these causes.

Standardized pachymetry-assisted manual lamellar dissection for Descemet stripping endothelial keratoplasty.

To present an alternative technique (Pachy-DSEK) for the manual preparation of thin endothelial lamellae in Descemet stripping endothelial keratoplasty (DSEK), as well as to evaluate its visual and anatomic outcomes. A retrospective chart review was conducted in 15 cases who underwent DSEK at a private eye clinic in Brazil (INOB, Brasília) from June 2017 to December 2019. All patients had ocular comorbidities and relative contraindications to Descemet membrane endothelial keratoplasty (DMEK). All endothelial lamellae were manually prepared by using a standardized technique. Best corrected visual acuity (BCVA), tomographic parameters and graft's thickness were evaluated preoperatively and at 6 months. Endothelial cell counts were evaluated preoperatively and at 12 to 24 months. During preparation there was one case (6%) of peripheral tear and no tissue was lost. At 6 months, the median BCVA improved from 1.60 to 0.40 logMAR (p = 0.0009). There was no significant change in anterior (p = 0.507) and posterior astigmatism (p = 0.483), anterior (p = 0.683) and posterior mean keratometry (p = 0.767), and total corneal power (p = 0.952). The median central graft thickness at 6 months was 80 µm. Ultrathin grafts (<130 µm) were achieved in 80% of cases. At 12 to 24 months endothelial cell count decreased significantly. Graft's detachment occurred in two cases (13%) and endothelial rejection in one case (6%). By using ultrasonic pachymetry intra-operatively and standardizing graft preparation, most manually dissected endothelial lamellae were ultrathin. Pachy-DSEK was safe and effective for treating endothelial disfunction in eyes with ocular comorbidities. It may be a cost-effective alternative to automated dissection methods.

Ultrathin Descemet stripping automated endothelial keratoplasty versus Descemet membrane endothelial keratoplasty: a fellow-eye comparison

BackgroundTo compare the visual outcome and patients’ satisfaction after ultrathin Descemet stripping automated endothelial keratoplasty (UT-DSAEK) and Descemet membrane endothelial keratoplasty (DMEK) performed on fellow eyes of the same patients.MethodsIn this retrospective study, the records of 18 pseudophakic patients affected by Fuchs endothelial dystrophy who underwent DMEK in one eye and UT-DSAEK in the fellow eye were reviewed. Best corrected visual acuity (BCVA), corneal pachymetry, keratometry, corneal aberrations, photopic and mesopic contrast sensitivity, and endothelial cell counts measured 12 months after surgery in either eye were analyzed and compared. The results of a satisfaction questionnaire were also reviewed.ResultsTwelve months after surgery, BCVA was not significantly different in UT-DSAEK and DMEK eyes (0.10 ± 0.04 and 0.07 ± 0.07 logMAR, respectively); at both 4- and 6 mm optical zones total and posterior corneal higher order aberrations (HOAs), posterior astigmatism and total coma were significantly lower after DMEK; BCVA in both groups was significantly correlated mainly with anterior corneal aberrations; contrast sensitivity was higher after DMEK especially in mesopic conditions and at medium spatial frequencies; the endothelial cell density was similar, although slightly higher in the UT-DSAEK group (p = 0.10). The satisfaction questionnaire showed that although patients were highly satisfied from both procedures, more than half of them preferred DMEK and reported a more comfortable and quicker postoperative recovery.ConclusionsDMEK and UT-DSAEK showed no evidence of difference in terms of postoperative BCVA, although DMEK had a better performance in terms of contrast sensitivity, posterior corneal aberrations and overall patient satisfaction.

Posterior Corneal Surface Changes After Pterygium Excision Surgery

To evaluate the effect of pterygium excision on the posterior corneal surface and analyze the factors associated with those changes. A prospective, interventional study including 33 eyes of 31 patients who underwent pterygium excision at the Tel Aviv Medical Center (Tel Aviv, Israel). Exclusion criteria included corneal dystrophy, pseudopterygium, corneal scarring, or previous ocular surgery in the treated eye. Data were obtained by using the Galilei dual Scheimpflug analyzer. Recorded posterior corneal data included steep keratometry, flat keratometry, mean keratometry, corneal astigmatism, best-fit sphere, and the squared eccentricity index (e). Posterior surgically induced astigmatism (SIA) was calculated to demonstrate the astigmatic effect of surgery. Anterior-segment high resolution optical coherence tomography was used to measure pterygium dimensions (depth and horizontal/vertical size). The mean age was 53.7 ± 16.7 years. Posterior corneal SIA was 0.9 ± 1.1 D (P < 0.001) and was significantly correlated with age (r = 0.568, P = 0.002), horizontal pterygium size (r = 0.387, P = 0.046), and preoperative posterior astigmatism (r = 0.688, P < 0.001). In a multivariable analysis, only age (coefficient = 0.010, P = 0.038) and preoperative posterior astigmatism (coefficient = 0.648, P = 0.002) remained significant. Pterygium dimensions were not significantly associated with SIA magnitude. Flat keratometry steepened by 0.5 ± 1.1 D (P = 0.019), mean keratometry steepened by 0.3 ±0.6 D (P = 0.035), posterior astigmatism was reduced by 0.4 ± 1.2 D (P = 0.072), and e decreased by 5.1 ± 17.3 (P = 0.021). Pterygium excision has a significant astigmatic effect on the posterior corneal surface. The astigmatic effect increases with age and with higher preoperative posterior astigmatism. Pterygium depth and size are not associated with the degree of surgical astigmatic effect.

One-year visual and astigmatic outcomes of keratoconus patients following sequential crosslinking and topography-guided surface ablation: the TOPOLINK study.

To evaluate long-term visual and astigmatic outcomes of sequential corneal crosslinking (CXL) followed by topography-guided photorefractive keratectomy (PRK). Single-practice outpatient setting. Retrospective case review. This is a single-surgeon retrospective case review of eyes with keratoconus undergoing sequential CXL and then topography-guided PRK. Change in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), topographic, refractive, and keratometric astigmatism was analyzed using power vector analyses at baseline, 6 months, and 12 months after topography-guided PRK. Changes in higher-order aberrations (HOAs), posterior astigmatism, spherical equivalent (SE), and central corneal thickness (CCT) were also analyzed. Correlations between age, time between CXL and PRK, sex, manifest SE, CCT, maximum and average keratometric values, and HOAs were evaluated for significance. Of the 62 eyes studied, regardless of refractive treatment, topography-guided PRK following CXL in patients with keratoconus improved CDVA (mean 20/30; 2-line improvement) and UDVA (mean 20/50; 4-line improvement). Over 12 months, visual acuity continued to improve across all eyes treated (P < .001). Overall, there were significant improvements in corneal astigmatism, maximum keratometry, mean keratometry, SE, posterior astigmatism, and total HOAs. No significant correlations were found between age, sex, time elapsed between CXL and PRK, and age at the time of either procedure on final visual acuity. Results of this study reinforced previous findings that topography-guided PRK in previously cross-linked keratoconus eyes proves to be an efficacious and safe method for improving visual acuity and reducing irregular corneal astigmatism, with continued improvement.

Toric intraocular lens implantation in cataract patients with corneal opacity

BackgroundTo evaluate the effect of toric intraocular lens implantation in cataract patient with corneal opacity and high astigmatism.MethodsThirty-one eyes of 31 patients who underwent cataract surgery with toric intraocular lens implantation were included. All patients had corneal opacity with astigmatism. Preoperative total corneal astigmatism was determined considering posterior astigmatism using a rotating Scheimpflug camera (Pentacam®: Oculus, Wetzlar, Germany). At 2 months after toric intraocular lens implantation, we evaluated residual astigmatism, uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA).ResultsPostoperative UCVA and BCVA (0.30 ± 0.17, 0.22 ± 0.16LogMAR) were statistically improved compared to preoperative UCVA and BCVA (1.2 ± 0.34, 1.1 ± 0.30LogMAR, respectively) (P < 0.01). Postoperative residual refractive astigmatism (1.2 ± 0.35D) was statistically reduced compared to preoperative refractive astigmatism (2.4 ± 0.65D) (P < 0.05). Preoperative and postoperative total corneal astigmatism values were not statistically different. All eyes achieved postoperative visual acuity as good as or better than preoperative one. The size of corneal opacity covering pupil had significant negative correlation with postoperative UCVA and BCVA (logMAR) (R = 0.91 P < 0.05 and R = 0.92 P < 0.05, respectively).ConclusionToric intraocular lens implantation can improve UCVA, BCVA, and refractive astigmatism in cataract patient with corneal opacity. The size of corneal opacity covering pupil is the major prognostic factor for postoperative visual improvement. Therefore, toric intraocular lens implantation should be considered for cataract patients who have corneal opacity with high astigmatism.