Mean Keratometry Research Articles

Combined DSAEK With Cataract Surgery in a Patient With Fuchs Endothelial Corneal Dystrophy and Keratoconus After Corneal Crosslinking

Purpose: To report a combined Descemet stripping automated endothelial keratoplasty (DSAEK) with cataract surgery in a case of Fuchs endothelial corneal dystrophy (FECD) and keratoconus after corneal crosslinking combined with photorefractive keratectomy. Methods: We report a case of a 56-year-old woman with a history of subclinical keratoconus who underwent corneal crosslinking (CXL) plus 7 years ago. At presentation, the patient complained of blurry vision, which was more prominent in the morning over the past few years, and frequent changes of spectacle prescription ever since the initial treatment with CXL plus. Post-CXL plus corneal tomographies revealed progressive corneal flattening of 6.20 diopters (D) and 6.50 D in the right (OD) and left (OS) eye, respectively, in terms of mean keratometry values over a period of 7 years, which resulted in significant hyperopia. Corrected distance visual acuity (CDVA) at presentation was 20/50 in the OD and 20/200 in the OS. Slit-lamp examination revealed guttae (diagnosis of FECD) with associated posterior corneal edema and advanced nuclear sclerotic cataracts in both eyes. Combined DSAEK with cataract surgery was performed on the left eye. Results: One year after the combined procedure, CDVA improved to 20/25, with the correction of (−0.25, −4.25 × 25). Slit-lamp examination revealed a clear cornea without evidence of corneal edema or scarring. Corneal tomography indicated discontinuation of the corneal flattening in the left eye while the fellow eye continued to flatten. Conclusions: Combined DSAEK with cataract surgery provides an effective surgical option for patients with FECD after CXL plus procedures for keratoconus, offering fast visual rehabilitation and functional visual outcomes.

Anterior scleral thickness in Marfan syndrome: A quantitative analysis.

To investigate the anterior scleral thickness (AST) in patients with Marfan syndrome (MFS). A prospective, cross-sectional study was conducted at the Department of Ophthalmology, Ghent University Hospital, Ghent, including patients with a genetically confirmed clinical diagnosis of MFS and age-, gender- and axial length-matched controls. Subjects with known corneal, conjunctival or scleral pathology and a history of ocular surgery, including pars plana vitrectomy, recent contact lens use or high-grade astigmatism were excluded. Subjects underwent non-cycloplegic autorefraction, Scheimpflug-based corneal tomography, axial length measurement and spectral-domain optical coherence tomography (OCT). AST was manually measured at 1 mm (AST1), 2 mm (AST2) and 3 mm (AST3) from the scleral spur, temporally and nasally. A total of 56 subjects (28 subjects in the MFS group and 28 matched subjects in the control group) were included in this study. In patients with MFS, AST was significantly reduced compared to matched controls, both overall and at every analysed measuring point in the nasal and temporal areas (p < 0.001). Central corneal thickness (CCT) and mean keratometry (Kmean) values were significantly lower in patients with MFS (p < 0.05). A positive correlation was found between nasal AST and CCT in patients with MFS. No correlation was found between AST and Kmean or between AST and axial length. In patients with MFS with ectopia lentis, compared to those without, temporal AST3 was significantly lower (p < 0.05). AST was significantly lower in patients with MFS harbouring a variant predicted to cause haploinsufficiency compared to those with a variant expected to lead to a dominant negative effect for both nasal and temporal measurements. Based on anterior segment OCT measurements, AST of patients with MFS is significantly lower compared to matched controls.

Comparison of Surgically Induced Astigmatism Following Manual Sics: Superior and Temporal Approach

Aim: The operable cataract cases in the developing world is high compared to the cataract surgical rate, and economical and effective methods are required to deal with this curable blindness, in order to provide the highest achievable uncorrected distance visual acuity. This study aimed to compare the surgically induced corneal astigmatism in patients undergoing manual small incision cataract surgery by superior (s-MSICS) and temporal (t-MSICS) scleral tunnel incisions. Methods: Prospective, interventional cases series of 60 eyes of 60 patients. Uncorrected distance visual acuity (UDVA), mean keratometry (KMean) and surgically induced astigmatism (SIA) were the main outcome measures which were compared between the two groups, s-MSICS and t-MSICS. Results: The mean patient age was 58.60 ± 7.11 years and 59.63 ± 8.39 years in the s-MSICS and t-MSICS groups respectively. Uncorrected distance visual acuity (UDVA) on day 90 was 0.27 ± 0.14 logMAR in the s-MSICS group and 0.18 ± 0.16 logMAR in the t-MSICS group (p=0.05). At the final assessment s-MSICS had 1.43 ± 0.99D of SIA and t-MSICS had 0.76 ± 0.66D of SIA (p=0.02). Four patients in the s-MSICS group and 25 patients in the t-MSICS group had WTR astigmatism (p&lt;0.001). Likewise, there were 26 cases of ATR and one case of ATR in the s-MSICS and t-MSICS respectively (p&lt;0.001). Conclusion: In this prospective study, t-MSICS had significantly lesser surgically induced astigmatism than s-MSICS. The temporal incision decreased against the rule astigmatism, as well, which is the astigmatism prevalent in the adult population.

Association of Novel Loci With Keratoconus Susceptibility in a Chinese Genome-Wide Association Study.

Keratoconus (KC) is a progressive corneal disease that can lead to corneal blindness if not properly managed. The purpose of this study was to identify genetic associations with KC in China and to investigate whether these genetic variants are associated with corneal thickness and corneal curvature in KC cases. A genome-wide association study was conducted on 853 patients with KC and 6248 controls. The KC cases were genotyped with the Illumina Infinium Human Asian Screening Array BeadChip, and the controls were genotyped with the Illumina Infinium Human Global Screening Array BeadChip. Genetic associations with KC, as well as correlations between the positive variants and corneal parameters including central corneal thickness (CCT) and mean keratometry (Km), were compared using PLINK version 1.90. Our present study identified four single-nucleotide polymorphisms (SNPs) within four risk loci (PTGER3: rs2300163, EYA1: rs1077435, ASS1: rs141365191, and CHTF8: rs3743680) associated with KC in Chinese patients that reached genome-wide significance. Among the identified SNPs with P < 1.00 × 10-4, seven SNPs (FOSL2-PLB1: rs12622211, RXRA-COL5A1: rs3118515, rs3132306, rs1536482, rs3118520, KAT6B: rs192187772, RAP2A-IPO5: rs41361245) were observed to be associated with CCT, and one SNP (USP13: rs6767552) was found to be associated with Km. In the first genome-wide association study of KC with a relatively large study population in China, we identified four SNPs in four risk loci associated with the disease. The findings enriched the understanding of genetic susceptibility to KC and provided new insights into the genetic etiology of the disease.

Comparison of IOL power formulas in eyes with a flat cornea

PurposeTo assess and compare accuracy of intraocular lens (IOL) power calculation performed with old generation, new generation and artificial intelligence (AI)-based formulas in eyes with flat corneas. DesignPatients with a tomography-derived mean keratometry <42 D were retrospectively recruited among those who underwent uncomplicated phacoemulsification with intracapsular IOL implantation in two different tertiary care centers. Mean prediction error (ME), mean absolute prediction error (MAE) and incidence of MAE>0.25D were calculated for Barrett Universal II (BUII),EVO 2.0, Hoffer QST, Kane, Olsen-C, Pearl-DGS and SRK/T formulas. Linear correlation between MAE and axial length was also calculated for each formula. ResultsEighty (80) eyes with a mean keratometry of 41.4 ± 0.6 D (range 40.6–41.9 D) were recruited. The SRK/T significantly differed from both the Olsen-C (p = 0.022) and the BUII (p = 0.048) in ME. The EVO 2.0, the Hoffer QST, the Kane and the PEARL-DGS showed a significantly lower MAE compared to all other formulas (p < 0.001) and a significant lower incidence of MAE>0.25D (p < 0.001), MAE>0.50 D (p < 0.001) and MAE>1.0 D (0.002). ConclusionFormulas based on AI and on the theory of vergence show superior accuracy in IOL power calculation in corneas with low mean keratometry; their MAE is not correlated to axial length.

Repeatability and reproducibility of a new fully automatic measurement optical low coherence reflectometry biometer and agreement with swept-source optical coherence tomography-based biometer

AimsTo assess the repeatability and reproducibility of the ocular measurements obtained with the Suoer SW-9000 μm Plus, a new fully automatic biometer based on optical low coherence reflectometry (OLCR) biometer,...

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.

Comparison of refractive outcomes obtained with two swept-source OCT-based optical biometers after cataract surgery: A study of 152 eyes

To compare two swept-source OCT optical biometers, the Anterion® (Heidelberg Engineering GmbH, Heidelberg, Germany) and the IOLMaster 700® (Carl Zeiss Meditec AG, Jena, Germany), in the analysis of biometric data, intraocular lens (IOL) calculation and postoperative spherical equivalent predictability. This was a real-life, single-center, retrospective study including 152 eyes of 81 consecutive patients referred for cataract surgery. All patients were examined with the IOLMaster 700® and the Anterion®. Biometric data (axial length [AL], anterior chamber depth [ACD], mean keratometry [Km], K1 [flat keratometry], K2 [steep keratometry] and axis, TK1 [flat total keratometry], TK2 [steep total keratometry], central pachymetry, lens thickness [LT], white-to-white distance [WTW]), IOL calculation with the SRK/T formula, and postoperative refractive outcome at 1 month were compared. All biometric measurements were significantly different between the two biometers. Correlations were excellent for AL, pachymetry, ACD, LT and keratometry measurements, and for the IOL calculation (r>0.96, intraclass correlation coefficient=1). The IOL power for emmetropia was similar between both biometers when the SRK/T formula was used (20.84±3.24D versus 20.86±3.29D, P=0.61). The mean postoperative spherical equivalent prediction error calculated using the SRK/T formula was 0.03±0.5D for the IOLMaster 700® versus 0.01±0.47D for the Anterion® (P=0.12). This study showed excellent correlation and agreement for the biometric measurements and the IOL power calculation with the SRK/T formula between both biometers.

Comparative Evaluation of Topographic Parameters Using Three Different Topographers in Keratoconic and Cross-linked Keratoconic Corneas.

To compare the parameters of three different topographic devices (Pentacam HR, Oculus Optikgeräte GmbH; Sirius, Costruzione Strumenti Oftalmici; and Cassini, i-Optics) in grading the severity of keratoconus in cross-linked and non-cross-linked eyes. This was a prospective comparative interventional study done in a tertiary eye care center, wherein 114 eyes of 68 patients with keratoconus were divided into two groups: 62 eyes that were observed and 52 eyes that were cross-linked. All eyes were evaluated on all three topographers at baseline, 3-month follow-up, and 6-month follow-up. The Sirius showed significantly lower values of mean flat keratometry in comparison to the Pentacam HR (limits of agreement [LoA]: 1.75 to 3.51%) and Cassini (LoA: 1.75 to 3.51%). The mean steep keratometry values were higher for the Cassini in comparison to the Pentacam HR (LoA: 4.39 to 7.02%) and Sirius (LoA: 3.51 to 6.14%). The mean steep keratometry values of the Sirius were significantly lower than those of the Pentacam HR and in both the cross-linked and observation groups (LoA: 3.51 to 6.14%). The mean keratometry values were significantly higher in the Cassini compared to the Pentacam HR (LoA: 3.51 to 8.77%) and significantly lower in the Sirius in comparison to the Pentacam HR (LoA: 3.51 to 6.14%). The mean difference in astigmatism was also statistically significant between the three tomographers in both groups, with the Cassini showing higher values (LoA: 3.51 to 5.26%) and the Sirius lower values than the Pentacam HR (LoA: 5.26 to 6.14%). The authors conclude the three devices cannot be used interchangeably. The Cassini showed better agreement and correlation with the Pentacam HR in the staging of keratoconus, whereas the Sirius tended to underdiagnose and under-stage the disease. [J Refract Surg. 2024;40(4):e260-e269.].

Tissue Saving by Reducing and Using Variable Optic Zone (VOZ) to Correct Myopia by Refractive Lenticule Extraction

Purpose: The lenticular diameter was reduced to below standard 6.5 mm, in a stepwise manner up to 5.2 mm and report on the Residual Stromal Thickness (RST), refractive outcomes and subjective scotopic visual quality of patients compared to those who underwent Small Incision Lenticule Extraction (SMILE) with the conventional 6.5 mm lenticular diameter. Study Design: Retrospective study Methods: Patients undergoing SMILE in the first year of the study were subjected to lenticular diameter of standard 6.5 mm for lenticule extraction. In the second year, using the same nomogram, the lenticular diameter was gradually reduced from 6.4 to 6 mm, with 0.1 mm decrements in each subset. In the last 6 months, all cases were performed using the same nomogram but with lenticular diameter below 6 mm, again with 0.1 mm decrements in each subset. Results: We included 100 eyes of 55 patients with a mean age of 26.18+ 6.6 years (median=25 years, IQR= 22 to 28 years). The mean preoperative best corrected visual acuity (BCVA) was 0.03+ 0.07 logMAR (range = 0 to 0.3 logMAR) and the mean preoperative spherical equivalent was -5.5D + 2.05D (median = -5.5D, IQR= -7.10 to -3.75D). The mean keratometry was 44.12D + 1.3D (range = 41.5 to 48D) and mean central corneal thickness was 532.24+ 29.8 µ (median = 533 µ IQR= 511 to 552 µ, range = 449 to 629 µ). The pupillary size in the study group was 3.80+ 0.82 mm (median= 3.84 mm, IQR= 3.3 to 4.3mm). At 1 month follow up; the best corrected distance visual acuity (UCDVA) across groups was 0.02 + 0.06 logMAR (median = 0 logMAR, range = 0 – 0.3 logMAR). There were no differences in UCDVA and contrast sensitivity between groups with respect to the lenticular diameter. Univariate linear regression analysis showed that age, spherical equivalent, preoperative pachymetry and lenticular diameter size were significantly associated with residual stromal thickness. Conclusion: We found that SMILE performed with a lenticular diameter of &lt; 6 mm was effective in delivering excellent refractive correction and improving the corneal biomechanical strength by virtue of significantly greater RST.

Conventional Epithelial-Off Corneal Crosslinking in Patients With Progressive Keratoconus: 10-Year Outcomes.

Corneal crosslinking (CXL) is the standard treatment of progressive keratoconus (KC). We evaluated the safety and 10-year outcomes of conventional "epithelial-off" CXL for progressive KC for the first time in a cohort in France. We conducted a retrospective review of patients undergoing conventional CXL (Dresden protocol) in our tertiary ophthalmology department from 2006 to 2011 with 10-year follow-up. The primary outcome was change in preoperative versus postoperative keratometry measured by maximum keratometry (Kmax), steep keratometry (K2), flat keratometry (K1), mean keratometry (Km), and topographic cylinder. Secondary outcomes were changes in visual and refractive outcomes. We report postoperative complications and adverse events. Eighty-nine eyes from 76 patients (67% male patients, mean age 22.7 ± 7.6 years) were included. Mean Kmax (-2.31 ± 2.98 diopters (D); P < 0.00001), K2 (-2.07 ± 3.15 D; P < 0.00001), K1 (-1.00 ± 2.29 D; P = 0.00008), Km (-1.53 ± 2.47 D; P < 0.00001), and topographic cylinder (-1.15 ± 2.53 D; P = 0.00004) significantly decreased 10 years after CXL compared with preoperative baseline. Significant decreases were still observed between 5 and 10 years after for mean Kmax, mean K2, mean K1, and mean Km. Mean distance best spectacle-corrected visual acuity and mean manifest refraction spherical equivalent were significantly improved after 10 years versus before CXL. The 10-year rate of repeat CXL was n = 3/76 patients (4%) (all younger than 18 years at first CXL) and of loss of >3 lines in best spectacle-corrected visual acuity was n = 1/76 patients (1%). Progressive KC was effectively stabilized with a prolonged flattening and maintenance of functional vision improvements after 10 years. Repeat CXL was rare and only required among younger patients.

Evaluation of a new dynamic real-time visualization 25 kHz swept-source optical coherence tomography based biometer

BackgroundTo evaluate the intraobserver repeatability and interobserver reproducibility of a newly developed dynamic real-time visualization 25 kHz swept-source optical coherence tomography (SS-OCT) based biometer (ZW-30, TowardPi Medical Technology Ltd, China) and compare its agreement with another SS-OCT based biometer (IOLMaster 700, Carl Zeiss Meditec AG, Jena, Germany).MethodsEighty-two healthy right eyes were enrolled in this prospective observational study. Measurements were repeated for three times using the ZW-30 and IOLMaster 700 in a random order. Obtained parameters included axial length (AL), central corneal thickness (CCT), aqueous depth (AQD), anterior chamber depth (ACD), lens thickness (LT), mean keratometry (Km), astigmatism magnitude (AST), vector J0, vector J45, and corneal diameter (CD). The within-subject standard deviation (Sw), test–retest (TRT) variability, coefficient of variation (CoV), and intraclass correlation coefficient (ICC) were adopted to assess the intraobserver repeatability and interobserver reproducibility. The double-angle plot was also used to display the distribution of AST. To estimate agreement, Bland–Altman plots were used.ResultsFor the intraobserver repeatability and interobserver reproducibility, the Sw, TRT and CoV for all parameters were low. Meanwhile, the ICC values were all close to 1.000, except for the J45 (ICC = 0.887 for the intraobserver repeatability). The double-angle plot showed that the distribution of AST measured by these two devices was similar. For agreement, the Bland–Altman plots showed narrow 95% limits of agreements (LoAs) for AL, CCT, AQD, ACD, LT, Km AST, J0, J45, and CD (− 0.02 mm to 0.02 mm, − 7.49 μm to 8.08 μm, − 0.07 mm to 0.04 mm, − 0.07 mm to 0.04 mm, − 0.07 mm to 0.08 mm, − 0.16 D to 0.30 D, − 0.30 D to 0.29 D, − 0.16 D to 0.16 D, − 0.23 D to 0.13 D, and − 0.39 mm to 0.10 mm, respectively).ConclusionsThe newly dynamic real-time visualization biometer exhibited excellent intraobserver repeatability and interobserver reproducibility. The two devices both based on the SS-OCT principle had similar ocular parameters measurement values and can be interchanged in clinical practice.

Factors predicting the visual outcome of intracorneal ring segment for keratoconus.

To identify predictive factors and to construct predictive models using epidemiological and clinical preoperative factors for the visual acuity change after intracorneal ring segment (ICRS) implantation in patients with keratoconus. The medical records of 287 keratoconic eyes of 230 patients implanted with ICRS at Chula Refractive Surgery Center of a tertiary university hospital (Bangkok, Thailand) between January 2012 and March 2022 were retrospectively reviewed for epidemiological and clinical preoperative variables, including those derived from Scheimpflug tomography. After randomly excluding one eye for each bilateral case, the remaining 230 eyes were randomized into two groups: a training group (184 eyes) and a validation group (46 eyes). In the training group, the correlation between the interesting variables and postoperative uncorrected and corrected distance visual acuity change (ΔUDVA and ΔCDVA; logMAR scale) at 6 months was explored, and then the multiple linear regression analysis was used to develop the predictive models. The obtained models were tested using the validation group. There were 5 and 14 preoperative variables that statistically correlated with ΔUDVA and ΔCDVA respectively. Only the preoperative corrected distance visual acuity (CDVAp) strongly correlated with ΔCDVA (Beta = -0.746). Using multiple regression, the preoperative uncorrected distance visual acuity (UDVAp) and front mean keratometry were selected in the proposed model for ΔUDVA (adjusted R2 = 38.8%), while the CDVAp and index of surface variance (ISV) were selected in the model [Formula: see text] (adjusted R2 = 48.9%). The ΔUDVA and ΔCDVA models were correct in 47.83% and 63.4% of the validation group within 0.20 logMAR, respectively. Potential predictive factors and models for ICRS-induced changes in visual acuity are proposed as adjunctive tools for clinicians. Such tools could be used for case selection and during counselling before ICRS implantation to maximize surgical outcomes.

Hyperopic LASIK and postoperative corneal steepness: revisiting the 49-diopter limit.

To compare corrected distance visual acuity (CDVA) outcomes of hyperopic laser in situ keratomileusis (LASIK) with a postoperative corneal steepness above vs below 49 diopters (D). Care-Vision Laser Centers, Tel-Aviv, Israel. Retrospective study. This study included consecutive patients who underwent hyperopic LASIK between January 2013 and December 2019. Hyperopic patients were divided into 2 groups based on postoperative corneal steepness with steep corneas defined >49.0 D and the control group ≤49.0 D. Adjustments were performed to account for differences in baseline and intraoperative parameters. Overall, 1703 eyes of 1703 patients were included. Mean age was 48.3 ± 10.0 years, and 45.3% were male. Preoperatively, the steep group (2.4%, n = 41/1703) had steeper mean (44.6 D vs 43.1 D, P < .001) and steep (45.1 D vs 43.5 D, P < .001) keratometry, worse logMAR CDVA (0.07 vs 0.04, P = .02), and higher sphere (4.9 D vs 2.9 D, P < .001). Intraoperatively, they had a higher spherical treatment (4.6 D vs 2.8 D, P < .001). After hyperopic LASIK, the steep group had worse logMAR CDVA (0.10 vs 0.06, P = .01). However, after accounting for differences in baseline and spherical treatment, no significant differences were found in postoperative logMAR CDVA (0.06 vs 0.06, P = .99). The factors that remained associated with worse postoperative CDVA were higher spherical treatment (0.01 logMAR per 1 D, P < .001) and preoperative CDVA (0.60 logMAR per 1.00 logMAR, P < .001). Postoperative corneal steepness greater than 49 D is not associated with worse visual outcomes after hyperopic LASIK. However, lower preoperative visual potential and higher spherical treatment applied are associated with worse outcomes. The 49 D cutoff should be revisited.

Safety and efficacy of implantable phakic contact lens versus implantable collamer lens in myopia correction.

Phakic intraocular lenses (pIOLs) have proven to be excellent substitutes for excimer laser keratorefractive surgery in certain situations. We aimed to assess the efficacy and safety of two pIOLs, the implantable collamer lens (ICL V4c) versus the implantable phakic contact lens (IPCL V2), for myopic correction. In this prospective randomized clinical trial, we allocated eligible eyes with myopia > - 6 diopters into IPCL or ICL implantation groups, each including 100 eyes of 100 individuals. Preoperative and postoperative assessments at 3, 6, and 12 months included measurements of the spherical equivalent (SE), uncorrected distance visual acuity (UCDVA), best-corrected distance visual acuity (BCDVA), intraocular pressure (IOP), maximum keratometry (K1), minimum keratometry (K2), mean keratometry (Kmean), anterior chamber depth (ACD), anterior chamber angle (ACA), and endothelial cell density (ECD). The groups had comparable demographic characteristics and baseline visual and anatomical values (all P > 0.05). The UCDVA, BCDVA, and SE of the two groups were comparable at baseline and at all postoperative follow-up examinations (all P > 0.05). Both groups experienced significant improvements in UCDVA, BCDVA, and SE at three months postoperatively (all P = 0.001), and measurements remained stable for up to 12 months. Keratometry readings were comparable between the groups over the follow-up period and remained unchanged at all visits (all P > 0.05). The ACA in the ICL group was significantly decreased at three months postoperatively (P = 0.001) and then widened significantly at 6 and 12 months (both P = 0.001). In the IPCL group, the postoperative ACA was significantly decreased at three months (P = 0.001) and was comparable to that in the ICL group (P > 0.01). However, at the 6- and 12-month postoperative visits, the ACA was significantly narrower in the IPCL group than in the ICL group (both P = 0.001). The ACD in both groups was decreased at three months postoperatively (both P = 0.001) and remained stable until the end of the study. The ECD remained comparable between the groups at all postoperative visits (all P > 0.05). We did not observe a significant ECD reduction in either group at any postoperative follow-up visit (all P > 0.05). We encountered no serious complications in either group. ICL and IPCL had comparable safety and efficacy outcomes in terms of anterior chamber morphometrics, visual and refractive results, and corneal parameters. Further multicenter randomized clinical trials with longer follow-up periods, larger sample sizes, and measurement of additional anterior chamber and corneal morphometrics, vault, and other vision parameters are needed to verify these findings.

Assessment of corneal parameters in patients with rheumatoid arthritis.

To assess the corneal parameters in rheumatoid arthritis (RA) patients. We enrolled 64 patients with RA (32 receiving biologic and 32 receiving conventional drugs) and 32 healthy subjects. Keratometric values (anterior flat [K1], steep [K2], and mean keratometry [Km]), corneal thickness from the pupil center (CCT), apex (ACT), and the thinnest point (TCT), and corneal volume (CV) were measured and compared between the groups. K1, K2, and Km values were significantly higher in the RA group (P = 0.013, P = 0.048, P = 0.027, respectively). The means of CCT, ACT, TCT, and CV were significantly lower in RA patients (P < 0.001, P < 0.001, P < 0.001, P = 0.011, respectively). When we divided RA patients into two groups according to the treatment and compared them to controls, the differences in K1, CCT, ACT, TCT and CV were significant (P = 0.030, P = 0.005, P = 0.001, P = 0.001, P = 0.034, respectively). K1 and CV values of RA-biologic group were similar to the control group (P = 0.205 and P = 0.127, respectively). Biologic agents contribute to the improvement of K1 and CV values in patients with RA.

The influence of age and gender on ocular biometrics and corneal astigmatism in adults undergoing cataract surgery

Objectives: To assess the influence of age and gender on ocular biometric values and corneal astigmatism features in individuals undergoing phacoemulsification surgery and intraocular lens implantation. Methodology: This retrospective study measured ocular biometrics and corneal keratometric astigmatism using the IOLMaster 700 instrument prior to phacoemulsification surgery and intraocular lens implantation. Results: Analysis included ocular biometric and keratometric values from 3385 eyes of 3385 patients. Lens thickness ( p &lt; 0.001, r = 0.387), mean keratometry ( p &lt; 0.001, r = 0.156), and corneal astigmatism ( p &lt; 0.001, r = 0.082) were positively correlated with age. Conversely, axial length ( p &lt; 0.001, r = −0.133), anterior chamber depth ( p &lt; 0.001, r = −0.244), and horizontal white-to-white corneal diameter ( p &lt; 0.001, r = −0.226) exhibited negative correlations with age. Increasing age led to a significant shift towards against-the-rule astigmatism ( p &lt; 0.001, r = 0.248). Mean keratometry was significantly lower in males than females ( p &lt; 0.001). Axial length, anterior chamber depth, lens thickness, and white-to-white corneal diameter were higher in males compared to females (all ps ⩽ 0.001). Corneal astigmatism types differed significantly between genders ( p &lt; 0.001), with against-the-rule being more prevalent among males (52.9%) and with-the-rule astigmatism having the highest prevalence among females (40.3%). Conclusions: Mean keratometry and lens thickness increased, while axial length and anterior chamber depth decreased with age. Males exhibited higher values for axial length, anterior chamber depth, and lens thickness, whereas females had steeper corneas.

Comparative analysis of corneal parameters between DMEK and UT‐DSAEK eyes in 3‐year follow‐up

Aims/Purpose: The aim of the study was to provide a comparative analysis of corneal parameter changes compared to their preoperative values between Descemet membrane endothelial keratoplasty (DMEK) and ultrathin Descemet stripping automated endothelial keratoplasty (UT‐DSAEK) patients.Methods: The study included 27 eyes after UT‐DSAEK and 34 eyes after DMEK. Best corrected visual acuity (BCVA), endothelial cell count (ECC), central corneal thickness (CCT), mean keratometry (MK), mean astigmatism (MA), astigmatism asymmetry (AA) and higher order aberrations (HOAs) were assessed at baseline and 1, 3, 6, 12, 24 and 36 months after the surgery.Results: Patients after DMEK had significantly better BCVA than patients after UT‐DSAEK (mean 0.9 vs. 0.6 at 24th month, respectively, p = 0.002 and 0.9 vs. 0.7 at 36th month of follow‐up, respectively, p = 0.001). From the 3rd month post operation, ECC was higher in the DMEK eyes than in the UT‐DSAEK eyes (p = 0.01). However, the groups did not differ in this parameter at 24th and 36th month of observation. In a bivariate analysis that was adjusted for age, DMEK was associated with a smaller decrease in posterior MK at the 1‐month (β = −0.49, p = 0.002), 3‐month (β = −0.50, p &lt; 0.001), 6‐month (β = −0.58, p &lt; 0.001) and 12‐month (β = −0.49, p &lt; 0.001) follow‐up visits. Significant differences in MK, AA and HOA values of the posterior surface of the cornea at 12th, 24th and 36th month of observation and MA of the posterior surface of the cornea at 24th month of observation were found as well, with no differences in the total values of these parameters. Accordingly, no significant differences in changes in MA, AA or HOAs compared to the baseline values were identified between the eyes after DMEK and UT‐DSAEK at any follow‐up time point.Conclusions: UT‐DSAEK seem to be an easier and safer technique than DMEK while maintaining similar outcomes regarding irregular astigmatism and total keratometry values. Nevertheless, DMEK produces significantly better BCVA outcomes.

Comparison of waveform‐derived ORA parameters in clinical keratoconus, subclinical keratoconus and healthy subjects

Aims/Purpose: The aim of this study was to comparison of waveform‐derived Ocular Response Analyser (ORA) parameters in clinical keratoconus (KC), subclinical keratoconus (SKC) and healthy subjects.Methods: This retrospective comparative case series study included 24 eyes with SKC, 24 eyes with KC and 48 eyes of age‐ and sex‐matched healthy subjects. Keratoconus diagnosis was based on clinical examinations, and Scheimpflug corneal tomography. SKC was defined as the presence of the following: (1) normal biomicroscopic findings and topography; (2) anterior (≤7 μm) and posterior (≤16 μm) elevation difference map marked green or yellow; (3) mean keratometry &lt;47D; (4) BAD‐D value &lt;3 SD and (5) keratoconus in the fellow eye. Thirty‐seven parameters derived from the waveform signal obtained with ORA were analysed. The Kruskal‐Wallis H test with Bonferroni correction was used for comparisons. p &lt; 0.05 was considered statistically significant.Results: While the rate of females in all groups was 33.3%, the mean age was 25.6 ± 0.9, 25.8 ± 1.3 and 25.7 ± 0.8 years in KC, SKC and healthy subjects, respectively. Statistically significant differences between KC and healthy eyes were found in p1area (p = 0.005), p2area (p &lt; 0.001), w1 (p = 0.001), w2 (p = 0.002), path1 (p = 0.032), path2 (p &lt; 0.001), aplhf (p = 0.018), p1area1 (p = 0.021), p2area1 (p &lt; 0.001), w11 (p = 0.028), w21 (p = 0.001), and path21 (p &lt; 0.001). While there were significant differences in w2 (p = 0.016), w21 (p = 0.042), and path21 (p = 0.033) parameters between SKC and healthy eyes, no significant difference was found between SKC and KC eyes.Conclusions: Approximately one‐third of the waveform‐derived ORA parameters can be used to differentiate between KC and healthy subjects. Parameters derived from the second applanation signal of ORA were superior in distinguishing SKC from healthy subjects.

Comparative analysis of corneal parameters in simple myopic anisometropia using Scheimpflug technology.

This study aims to investigate the differences in binocular corneal parameters and their interrelation with binocular biometric parameters asymmetry in patients with simple myopic anisometropia, thereby elucidating the influence of myopia process on various corneal parameters. In this cross-sectional study, 65 patients with anisometropia in monocular myopia were included. They were divided into low anisometropia group: 3.00D<Δ spherical equivalent (SE)≤-1.00D (Δ represents the difference between the two eyes, i.e., myopic data minus emmetropic data) and high anisometropia group: ΔSE ≤ -3.00D. Corneal and ocular biometric parameters were measured using Pentacam, Corvis ST, and IOL Master 700. Statistical analyses focused on the binocular corneal parameters asymmetry, using the contralateral emmetropia as a control. The mean age of participants was 18.5 ± 1.3 years, with the average SE for myopia and emmetropia being -2.93 ± 1.09D and -0.16 ± 0.41D, respectively. The central corneal thickness (CCT), flat keratometry (Kf), keratometry astigmatism (Ka), total corneal aberration (6mm) (TOA), surface variance index (ISV), vertical asymmetry index (IVA), stress-strain index (SSI), and first applanation stiffness parameter (SPA1) and ambrosia relational thickness-horizontal (ARTh) showed significant differences between anisometropic fellow eyes (p < 0.05). There were significant differences in ΔIVA, Δ the difference between the mean refractive power of the inferior and superior corneas (I-S), Δ deviation value of Belin/Ambrósio enhanced ectasia display (BAD-D), Δ deformation amplitude ratio max (2mm) (DAR)and Δ tomographic biomechanical index (TBI) (p < 0.05) in two groups. Asymmetry of corneal parameters was correlated with asymmetry of ocular biometric parameters. Anisometropia (ΔSE) was positively correlated with ΔIVA (r = 0.255, p = 0.040), ΔBAD-D (r = 0.360, p = 0.006), and ΔSSI (r = 0.276, p = 0.039) and negatively correlated with ΔDAR (r = -0.329, p = 0.013) in multiple regression analysis. Δ mean keratometry (Km), Δ anterior chamber depth (ACD), and Δ biomechanically corrected intraocular pressure (bIOP) were also associated with binocular corneal differences. Compared to contralateral emmetropia, myopic eyes have thinner corneas and smaller corneal astigmatism. Myopic corneas exhibit relatively more regular surface morphology but are more susceptible to deformation and possess marginally inferior biomechanical properties. In addition, there is a certain correlation between anisometropia and corneal parameter asymmetry, which would be instrumental in predicting the development of myopia.