Keratometry Measurements Research Articles

Postoperative corneal remodeling after corneal allograft intrastromal ring segment (CAIRS) implantation for keratoconus: An OCT study.

To demonstrate corneal remodeling after corneal allograft intrastromal ring segment (CAIRS) with an anterior-segment optical coherence tomography (AS-OCT). A prospective observational single-center study. This observational study included keratoconus patients who underwent CAIRS implantation into a stromal tunnel. Topographical, refractive, and visual changes were obtained from the patient records. Epithelial thickness (ET), anterior stromal thickness (AST), allograft corneal ring thickness (ACRT), and posterior stromal thickness (PST) were measured on the first day and 1, 3, 6, and 12 months postoperatively using AS-OCT. The study included 35 eyes of 27 patients with advanced keratoconus. The mean keratometry decreased from 48.26 ± 4.78 D to 44.50 ± 4.42 D at 1-year postoperatively (P = 0.004), mean corrected distance visual acuity increased from 0.29 ± 0.18 to 0.70 ± 0.24 (P < 0.001), and spherical equivalent (SE) decreased from -6.94 ± 4.32 D to -1.44 ± 4.44 D (P < 0.001). The mean AST decreased by 17.39 ± 5.78 μm in the postoperative 1st month compared to 1st day after surgery (P = 0.040). No statistically significant variations were observed in AST after the first month. There was no statistically significant difference in the mean ET, ACRT, and PST measurements between follow-up times. Significant negative correlations were found between SE change and ET (r = -0.543, P = 0.023) and between K1 change and ACRT (r = -0.548, P = 0.008). CAIRS is an effective treatment method to improve visual acuity and keratometry measurements and does not cause significant changes in graft thickness or recipient corneal epithelial and stromal thicknesses during the 1-year follow-up period. The observed correlations between SE, keratometry, and corneal thickness suggest that epithelial and stromal remodeling play crucial roles in postoperative outcomes of CAIRS.

Safety and efficacy of poly(methyl methacrylate), hydrophobic acrylic and hydrophilic acrylic intraocular lenses: A comparative clinical investigation

Objectives: Cataract surgery is a prevalent procedure for restoring vision in patients with cataracts. Intraocular lens (IOL) material selection significantly impacts outcomes. This study aimed to assess the safety and efficacy of poly(methyl methacrylate) (PMMA), hydrophilic, and hydrophobic IOLs in cataract surgery. The primary objective was to assess intraoperative safety and IOL performance. The secondary objective was to determine lens-related adverse events and visual acuity. Materials and Methods: This prospective clinical study included adult cataract patients undergoing IOL implantation at a single centre in India. Exclusion criteria included patients unwilling to participate, with previous intraocular or corneal surgery, traumatic cataract, pregnancy or lactation, concurrent participation in other drug or device investigations, unstable keratometry or biometry measurements, or irregular astigmatism. Patients with glaucoma and retinal disorders were also excluded. The study duration was one year with five follow-up visits. For the PMMA, hydrophilic, or hydrophobic IOLs 331, 340 and 330 eyes from 331, 340 and 330 patients were included respectively for the study. Intraoperative safety and performance were assessed through documented adverse events. Visual outcomes were evaluated at each visit using visual acuity measurements, slit-lamp examination, and intraocular pressure measurement. Results: No significant intraoperative complications or safety concerns were reported. There were no observed cases of IOL decentration, tilt, dislocation, discoloration, or opacity. Both distance uncorrected and distance best-corrected visual acuity (BCVA) showed significant improvement from baseline to the final visit in all groups. Conclusion: PMMA, hydrophilic, and hydrophobic IOLs demonstrated good safety and efficacy in cataract surgery, with significant improvement in visual acuity and no lens-related adverse events reported in this study.

Comparison of Corneal Keratometry Measured by Three Different Methods

To compare and evaluate the interchangeability and agreement between corneal keratometry measurements (flattest-steepest keratometry, mean keratometry and corneal astigmatism) using partial coherence interferometry reflectometry optical biometry (Nidek AL Scan, 2.4–3.3 mm zones, Nidek Technologies, Gamagori, Japan), corneal aberrometer/topographer (Nidek OPD Scan II, Nidek Technologies, Gamagori, Japan) and standard autorefractokeratometer (Topcon KR 8900, Topcon Inc., Tokyo, Japan) a total of 360 right eyes of 360 healthy volunteers with a mean age of 24.37±3.91 years were enrolled in this prospective comparative study. Paired t-tests were used to evaluate pairwise comparisons. The Bland–Altman test with 95% limits of agreement was used to evaluate the agreement between the three devices. There were no statistically significant differences between all keratometric values of the Nidek AL Scan obtained in the 2.4 and 3.3 mm zones (p&gt;0.05). There were no statistically significant differences in AstK values between the Nidek AL Scan (2.4 -3.3 mm zone) and the Nidek OPD Scan II pairwise comparisons (p&gt;0.05). When the K1, K2, and Kmean values measured with the Nidek OPD Scan II and Topcon KR 8900 were compared with the Nidek AL Scan (2.4 -3.3 mm zone), a statistically significant difference was found (p

Comparison of Ocular Biometry and Refractive Measurements from Myopia Master with Lenstar and KR-1 Autorefractor

Purpose: To compare axial length (AL), keratometry (K), and refractive measurements using Myopia Master, Lenstar, and KR-1 autorefractor.Methods: The study involved 44 eyes of 44 children who visited our clinic. We compared AL, flat K, steep K, mean K, and spherical equivalent (SE) measured by Myopia Master, Lenstar, and KR-1. We utilized a paired &lt;i&gt;t&lt;/i&gt;-test and RM-ANOVA to compare mean differences and used Bland–Altman plots, intraclass correlation coefficients (ICCs), and Pearson correlation tests for agreement analysis.Results: The mean ALs (mm) measured with Myopia Master and Lenstar were 24.59 ± 0.91 mm and 24.60 ± 0.91 mm, respectively, with no statistical differences (&lt;i&gt;p&lt;/i&gt; = 0.085). Both the ICC and Pearson correlation coefficient were 0.999. The mean SEs (D) measured with Myopia Master and KR-1 were -3.32 ± 1.75 D and -3.18 ± 1.68 D, respectively, with significant differences (&lt;i&gt;p&lt;/i&gt; &lt; 0.001). The ICC was 0.996 and the Pearson correlation coefficient was 0.995. The mean K (D) values measured by Myopia Master, KR-1, and Lenstar were 43.15 ± 1.59 D, 43.38 ± 1.58 D, and 43.32 ± 1.63 D, respectively, and differed significantly (&lt;i&gt;p&lt;/i&gt; &lt; 0.001).Conclusions: While statistical differences emerged in SEs between Myopia Master and KR-1, the differences were not clinically significant and the tools may be used interchangeably due to their good agreement. However, measured K values differed among Myopia Master, KR-1, and Lenstar, so these tools are not interchangeable. Based on the results from paired &lt;i&gt;t&lt;/i&gt;-tests, ICCs, and Pearson correlations, AL measurements were in good agreement between Myopia Master and Lenstar but caution should be exercised due to the wider range of measured values.

Effect of upper eyelid blepharoplasty with or without orbicularis oculi muscle removal on anterior segment parameters, keratometry, and ocular biometry.

To evaluate the effect of upper eyelid blepharoplasty with or without the removal of a strip of orbicularis oculi muscle on corneal topographic parameters, anterior segment parameters, intraocular pressure, and ocular biometry. This prospective study examined 428 eyes of 214 patients with dermatochalasis. Patients were divided into two groups randomly: those who underwent orbicularis oculi muscle excision (Group 1) during blepharoplasty and those who did not (Group 2). Following a detailed ophthalmological examination, corneal topography was used to evaluate the eyes anterior chamber depth (ACD), iridocorneal angle (ICA), keratometry measurements, and corneal astigmatism (CA) in the preoperative and postoperative first and third months. Ocular biometry was used to assess axial length (AXL) and intraocular lens (IOL) power. Goldmann applanation tonometry was used to measure intraocular pressure (IOP). The age and gender distribution between the groups were similar (p = 0.595 and p = 0.493, respectively). In Group 1, the mean steep keratometry (K2) value increased by 1.1 D and the mean CA increased by 0.81 D in the first month (p < 0.001 for both comparisons). The increases in K2 and CA were 0.7 D and 0.63 D, respectively, in Group 2 (p < 0.001 and p = 0.004, respectively). At the postoperative third month, both groups demonstrated statistically significant persistent elevations in K2 and CA values (p < 0.05 for all comparisons) compared to preoperative measurements. Group 1 exhibited statistically significant decreases in both IOL power calculations (0.43 D according to the Barrett formula and 0.40 D according to the SRK/T formula, p < 0.001, for both) and ICA (38.1 ± 4.7° vs. 35.8 ± 4.1°, p = 0.009) measurements at the only one-month postoperative follow-up. IOP, AXL, and ACD measurements did not exhibit any significant changes in both groups at the first and third postoperative months. In addition to changes in keratometry and CA, blepharoplasty with muscle excision significantly decreased IOL power and ICA. It may be beneficial to inquire about recent blepharoplasty history and the surgical technique employed in patients scheduled for cataract or refractive surgery.

The refractive accuracy between topographic keratometry and biometric keratometry for extended depth-of-focus intraocular lens implantation.

Purpose: To investigate the influence of different keratometry (K) measurements on the postoperative outcomes of cataract surgery with extended depth-of-focus (EDOF) intraocular lens (IOL) implantation. Methods: A retrospective cohort study was conducted, and patients who received cataract surgery and one type of EDOF IOL implantation were included. The patients were then categorized according to K measurements, and 70 and 30 eyes were included in the biometric-K and topographic-K groups, respectively. The primary outcomes were postoperative uncorrected distance visual acuity (UDVA), spherical equivalent (SE) and cylinder power. A generalized linear model was applied to compare the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of the outcomes between groups. Results: One month after surgery, the UDVA was 0.15 and 0.07 in the biometric-K group and topographic-K group, respectively. Furthermore, the final SEs were -0.42 D and -0.13 D in the biometric-K group and topographic-K group, respectively, and the final cylinder powers were -0.35 D and -0.13 D in the biometric-K group and topographic-K group, respectively. According to the multivariate analysis, the topographic-K group presented a significantly better UDVA (P = 0.044) and significantly lower cylinder power (P = 0.031) than the biometric-K group. Angle kappa was significantly correlated with high postoperative astigmatism in the topographic-K group (P = 0.033), whereas angle kappa, steep K, and corneal cylinder powers were significantly correlated with high postoperative astigmatism in the biometric-K group (all P < 0.05). Conclusion: Topography-based K measurements yielded better refractive outcomes than biometric-based K measurements did.

Comparative analysis of a novel spectral-domain OCT biometer versus swept-source OCT or OLCR biometer in healthy pediatric ocular biometry

With the advancements in ocular biometric technology, there have been significant improvements in accurately and efficiently measuring ocular parameters. The aim of this study is to compare the reliability of biometric parameters obtained using a new frequency-domain optical coherence tomography (SD-OCT) biometer with the measurements obtained from swept-source OCT (SS-OCT) and optical low coherence reflectometry (OLCR) biometers. This study employed an observational cross-sectional design. Measurements of axial length (AL), flat and steep corneal keratometry (K1 and K2), and central corneal thickness (CCT) obtained using the The Colombo IOL were compared with those obtained with the IOLMaster 700 and SW-9000 devices. The agreement were evaluated using intraclass correlation coefficient (ICC) and Bland–Altman analyses. The differences of the measurements of the three increments were assessed by one-way ANONA. 73 right eyes of 73 healthy pediatric subjects were analyzed. The AL difference measured by Colombo IOL compared with IOLmaster700 and SW-9000 were 0.00 ± 0.02 mm and − 0.07 ± 0.05 mm, respectively (P > 0.05, ANOVA). There was no statistically significant difference in CCT, K1, and K2 among the three instruments (all P > 0.05, ANOVA). The ICC values for AL, K1, K2, and CCT were 0.999, 0.996, 0.995, and 0.998, respectively. The Bland-Altman analysis showed an agreement of AL, K1, K2, and CCT with Colombo IOL and IOLMaster 700 spanned over 0.08 mm, 0.71D, 0.69D, and 12.17 μm, respectively. The agreement of AL, K1, K2, and CCT with Colombo IOL and SW-9000 spanned approximate 0.21 mm, 0.75D, 1.06D, and 14.37 μm, respectively. The new SD-OCT biometer and the SS-OCT biometer showed strong agreement in measuring AL and CCT in healthy pediatric subjects. This supports the reliability of the new SD-OCT biometer as an alternative for assessing these parameters. However, K1 and K2 could not be used interchangeably in clinical practice. Further research is needed to explore their applicability in different clinical settings and patient populations."light" />

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.

Comparison of the IOL Master and Pentacam in the measurement of anterior segment parameters in patients with high myopia and cataracts

This study aimed to compare the differences between the Zeiss IOL Master and Oculus Pentacam in keratometry and central anterior chamber depth (ACD) measurements in patients with high myopia and cataracts. Between January 2019 and December 2020, 89 patients (103 eyes) with cataracts and high myopia who underwent preoperative cataract evaluation at Nanchang First Hospital were selected for retrospective analysis. Keratometry (K1, K2) and ACD were measured with the IOL Master and Pentacam. Paired t-tests were performed to compare the differences, while the Bland-Altman method was used to evaluate the agreement. The K1 value was (43.15±2.44) D for the IOL Master and (42.98±2.47) D for the Pentacam, and the difference between the two instruments was statistically significant (P<0.01). The K2 value was (44.55±2.63) D for the IOL Master and (44.32±2.55) D for the Pentacam. The ACD was (3.44±0.33)mm for the IOL Master and (3.39±0.36)mm for the Pentacam. There were statistically significant differences between the two instruments in both keratometry and ACD (P<0.01). The absolute values of the maximum difference between the two instruments for K1 and K2 were 1.1 and 1.07; thus, the consistency of the two instruments with respect to this measurement was poor. However, the absolute value of the maximum difference between the two instruments for ACD was 0.34, so the consistency of the two instruments in relation to this measurement was good. Both the IOL Master and the Pentacam can be used in the measurement of keratometry and ACD in patients with high myopia and cataracts, but the keratometry measurements should be compared in clinical application.

Total and simulated keratometry measurements using IOLMaster 700 and Pentacam AXL after small incision lenticule extraction.

Calculating the intraocular lens (IOL) in patients after corneal refractive surgery presents a challenge. Because an overestimation of corneal power in cases undergone this surgery leading to a subsequent under-correction of IOL power. However, recent advancements in technology have eliable measurement of total corneal power. The aim of this research was to assess the agreement in simulated keratometry (SimK) and total keratometry (TK) values between IOLMaster 700 and Pentacam AXL. The study involved 99 patients (99 eyes) undergone small incision lenticule extraction (SMILE) surgery. Each patient underwent scans using IOL Master 700 and Pentacam AXL. The following parameters were recorded: SimK1, SimK2, Total K1 (TK1), and Total K2 (TK2) for IOLMaster 700; and SimK1, SimK2, True Net Power (TNP) K1, TNPK2, Total Corneal Refractive Power (TCRP) K1, and TCRP K2 for Pentacam AXL. Agreement between the two devices was evaluated using Bland-Altman plot, while paired t-test was utilized to compare any differences in the same parameter by both instruments. The results revealed a strong correlation between the two devices.Noticeable comparability was identified for all SimK variables. However, there were noticeable differences in TK measurements as well as TK1-TNPK1, TK2-TNP K2, TK1-TCRP K1, and TK2-TCRP K2 parameters when comparing the two devices. The IOLMaster 700 consistently measured steeper values than the Pentacam AXL, with significant and clinically relevant differences of 1.34, 1.37, 0.87, and 0.95 diopters, respectively. While there was a noticeable correlation between the IOLMaster 700 and Pentacam AXL in SimK measurements, a marked difference was noted in TK values. The two devices cannot be used interchangeably when quantifying TK values.

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.

Functional Approach to IOL Selection in Eyes With Combined Cataract and Keratoconus With an Option for Refractive Lens Exchange.

To evaluate spherical intraocular lens (IOL) implantation for cataracts in keratoconic eyes followed by optional refractive toric lens exchange to improve uncorrected visual acuity. This retrospective study evaluated cataract surgery outcomes in keratoconic eyes. Eyes treated with a spherical IOL targeted for -2.00 diopters (D) either achieved acceptable manifest refraction and desired exchange with a toric IOL (Group 1); achieved satisfactory manifest refraction and chose to use spectacles or contact lenses (Group 2); or did not achieve acceptable refraction and used contact lenses (Group 3). Group 4 had single-stage toric IOL implantation with plano target. Corrected and uncorrected distance visual acuity (CDVA and UDVA) and keratometry were analyzed. Groups 1 to 4 had 18, 23, 18, and 26 eyes, respectively. A staged toric exchange resulted in significantly better (P = .02) UDVA (mean: 0.15 logMAR; 20/25 Snellen) than initial toric IOL implantation (0.24 logMAR; 20/30 Snellen). All toric IOL exchange eyes achieved 20/30 or better CDVA and 94% had 20/40 or better UDVA. Mean manifest cylinder significantly decreased from 3.39 D before lens exchange to 1.10 D postoperatively. Initial implantation of a spherical IOL in keratoconic eyes allows basing toric calculations on the manifest refraction, which may be more reliable than keratometry measurements in keratoconic eyes. UDVA after staged toric IOL exchange was significantly better than after initial toric IOL implantation. Importantly, by staging use of toric lenses, the authors avoided cases where patients required a rigid contact lens after a toric IOL was implanted. [J Refract Surg. 2024;40(4):e207-e217.].

Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results.

To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters. In a separate sample of keratoconic eyes that had undergone cataract surgery, IOL power was calculated with the Barrett Universal II, Hoffer QST, Holladay 1, Kane, and SRK/T formulas using the SimK and an adjusted TCP power. The respective prediction errors were calculated. A total of 382 keratoconic eyes (271 patients) were enrolled. An increasing overestimation of SimK by TCP was detected from stage I to III, with a significant correlation between the SimK and TCP difference and SimK in the whole sample (P < .0001, r2 = 0.1322). Approximately 7% of cases presented an underestimation of SimK by TCP. IOL power calculation with the adjusted TCP improved outcomes, achieving a maximum of 80% of eyes with a prediction error within ±0.50 diopters with the Hoffer QST, Holladay 1, and Kane formulas. Overall, SimK overestimated TCP. Such a difference could not be predicted by any variable. The proposed TCP-adjustment formula (TCPadj = TCP + 0.56 diopters) in keratoconic eyes for IOL power calculation might be valuable for improving refractive outcomes. [J Refract Surg. 2024;40(4):e253-e259.].

Intrasession repeatability and agreement of the anterior corneal assessment provided by a multidiagnostic device

ABSTRACT Clinical relevance Multidiagnostic systems have recently appeared on the market. Knowledge of the repeatability and validity of any instrument is mandatory before its introduction in clinical practice. Background The aim of this work is to examine the intrasession repeatability of anterior pole measurements provided by the multidiagnostic device Wave Analyzer Medica 700 (WAM700) and agreement with Pentacam measurements in normal eyes. Methods In the right eyes of 113 participants, three repeat measurements of central keratometry, central corneal thickness, anterior chamber depth and corneal eccentricity were made with the WAM700 and Pentacam in random order. Intrasession repeatability and agreement were determined. Results Employing WAM700, intrasession repeatability for keratometry, central corneal thickness and anterior chamber depth was good (ICCs ≥ 0.992; CV 0.48–0.98%), yet worse than the values obtained for the Pentacam (ICCs ≥ 0.998; CV 0–0.33%). WAM700 showed excellent intrasession repeatability when used to measure the anterior chamber depth (Sw 0.03 mm). However, the repeatability of this device was inferior for central corneal thickness (Sw 4.24 μm) and keratometry measurements (Sw < 0.21 D) and was poor for corneal eccentricity (Sw 0.07; ICC 0.908; CV 14.58%). Agreement between WAM700 and Pentacam showed a high ICC for the keratometry measurements, central corneal thickness and anterior chamber depth (>0.972) but lower for corneal eccentricity (ICC 0.762). Conclusions In healthy eyes, the WAM700 multidiagnostic device showed good intrasession repeatability for keratometry, central corneal thickness and anterior chamber depth measurements. Agreement between WAM700 and Pentacam was good for the anterior chamber depth measurement. However, these instruments cannot be considered interchangeable for keratometry, central corneal thickness and eccentricity readings.

Differences in Keratometry Before and After Surgery Between Superior and Temporal Chevron Incision in Small Incision Cataract Surgery

Abstract&#x0D; Introduction &amp; Objectives : Cataracts are the most common cases that cause blindness globally, where the lense was haze and characterized by decreased visual acuity and is reversible if optimal treatment is given. Examination before surgery is very important for outcome, where keratometry is one of the examinations before the surgery. Small incision cataract surgery (SICS) is one of cataract surgery technique, where a chevron incision is used in the superior or temporal regions. This study aims to determine which location is the best for an incision based on the results of keratometry.&#x0D; Methods : This research is an analytical observational study, bidirectional (prospective-retrospective) with a cohort study approach conducted at the eye polyclinic of Sanglah Hospital and Surya Husadha Hospital, Denpasar. The study sample consisted of 46 eyes which were divided into two groups, 23 superior and 23 temporal incision, then the results were compared between groups.&#x0D; Results : The results showed that the oldest age was the temporal incision group, which was 66.78±7.11. In the keratometry measurements, it was found that there were differences between the two groups, where the temporal incision resulted in smaller keratometric changes (p=&lt;0.001). After analyzing the covariates, the temporal incision group still had smaller keratometry changes (p=&lt;0.001) with astigmatism as an influential confounding factor. Meanwhile, post-op visual acuity was found in the temporal incision group which was better than the superior incision after analysis with covariates (p=0.002).&#x0D; Conclusion : This study showed that the temporal incision group gave lower keratometry results and better post- op visual acuity than the superior incision group.

Paediatric norms for photopic electroretinogram testing based on a large cohort of Chinese preschool children

ObjectiveFull-field electroretinogram (ffERG) is an objective test to determine the electroretinal activities in response to light stimulation for investigating retinal physiology and diagnosing retinal diseases. This study aimed to establish...

Orthokeratology effect on the corneoscleral profile: Beyond the bull's eye.

To assess the impact of 3 months of orthokeratology (ortho-k) contact lenses (CLs) for myopia correction on the corneoscleral profile, as changes in scleral geometry could serve as indirect evidence of alteration in the corneal biomechanical properties. Twenty subjects (40 eyes) were recruited to wear ortho-k lenses overnight; however, after discontinuation (two CL fractures, one under-correction and two non-serious adverse events), 16 subjects (31 eyes) finished a 3-month follow-up. Corneoscleral topographies were acquired using the Eye Surface Profiler (ESP) system before and after 3 months of lens wear. Steep (SimKs) and flat (SimKf) simulated keratometry and scleral sagittal height measurements for 13-, 14- and 15-mm chord lengths were automatically calculated by the ESP software. Additionally, sagittal height and slope were calculated in polar format from 21 radii (0-10 mm from the corneal apex) at 12 angles (0-330°). Linear mixed models were fitted to determine the differences between visits. SimKs and SimKf were increased significantly (p ≤ 0.02). The sagittal height in polar format increased significantly (p = 0.046) at a radius of 2.5 mm for 150°, 180°, 210° and 240° orientations and at a radius of 3.0 mm for 210°. Additionally, the slope in polar format significantly decreased (p ≤ 0.04) at radii ranges of 0.0-0.5, 0.5-1.0 and 1.0-1.5 mmfor multiple angles and at a radii range of 5.0-5.5 mmfor 90°. It also increased significantly (p ≤ 0.045) at a radii range of 1.5-2.0 mmfor 30° and at radii ranges of 2.0-2.5, 2.5-3.0 and 3.0-3.5 mmfor multiple angles. No significant changes were found for any parameter measured from the scleral area. Three months of overnight ortho-k lens wear changed the central and mid-peripheral corneal geometry as expected, maintaining the peripheral cornea and the surrounding sclera stability.

Investigating Post-Operative Refractive Outcomes in Patients Undergoing Cataract Surgery to Assess the Potential Impact of a Concurrent Diagnosis of Dry Eye Disease (DED)

Cataract surgery is one of the most performed surgical procedures in the world. A cataract is defined as opaqueness in the interior of the ocular lens2. The exact etiology of cataracts is multifactorial ranging from environmental conditions to biochemical changes induced by aging3. The Intraocular lens (IOL) power calculation is an essential part of the pre-operative planning for cataract surgery as it determines the specific IOL that should be utilized for a patient. Keratometry measurements are required for this IOL power calculation, however, DED has been shown to cause inaccurate keratometry measurements4,5. We hypothesize that patients with DED undergoing cataract surgery will have a larger deviation from the predicted spherical equivalent (SE) post-operatively. Patients who were over the age of 18 and underwent cataract surgery were included. Patients who had a diagnosis of glaucoma, Herpes Simplex Keratitis, punctual plugs, undergone Laser-Assisted in Situ Keratomileusis (LASIK) surgery, Radial Keratometry, or any form of corneal scarring were excluded from this study as they can negatively impact keratometry measurements. The DED sample had a statistically significant larger SE deviation from the predicted SE compared to the healthy sample (p=0.037). The DED sample also had a statistically significant larger percentage of patients with an SE deviation of 0.50 D or greater (p=0.002). Finally, the DED had a statistically significant older age than the healthy group (p=0.028). The significant difference in age between the healthy sample and the DED sample confirms the significant correlation between age and prevalence of DED the literature has described6. The statistically significant increased post-operative SE deviation from predicted SE within the DED sample can be the result of the increased variability in the tear film associated with DED. This can lead to inaccurate keratometry measurements, thus leading to incorrect IOL power calculations.

Difficulty of biometric images and calculation of intraocular lens in a patient with Sjogren's syndrome

Aims/Purpose: To report a patient with a history of Sjogren's Syndrome and several ocular surface compromise with mature cataracts and difficult intraocular lens calculation.Methods: Case report and literature review.Results: A 75‐year‐old woman with a history of primary Sjogren's syndrome for almost 10 years with a long‐standing picture of foreign body sensation in both eyes, ocular burning, red eye and marked photophobia that was not improving despite several topical managements, currently with punctal plugs and using 0.5% carboxymethylcellulose, 0.4% sodium hyaluronate preservative free and ciclosporin emulsion 0.05%. Different topical treatments were used with any recovery on her ocular surface and the patient started developing dense cataracts in both eyes with important visual loss. The biometries performed were unreliable despite taking different images because of the great difficulty to get reproducibility on the keratometry measurements and for this reason it was not possible to predict the power of the lens to be implanted, we decided to try an aphakic refraction and multiply it by a conversion factor to get the power of the lens that was described long time ago in the literature. One month post‐op, the patient had a refraction of −1.50 −1.50 × 168° (0.3 LogMAR, J1) in the left eye and −0.50 −0.25 × 145° (0.3 LogMAR, J2) in the right eye.Conclusions: We have a great limitation of information to calculate intraocular lenses in those patients who, for different reasons and despite very complete treatments, cannot reach an optimal ocular surface. There is currently no consensus on IOL calculations in severe ocular surface diseases.

Swept-source optical coherence tomography in ocular surface diseases: anterior segment analysis repeatability and its limits.

This study aims to evaluate the repeatability of anterior segment optical coherence tomography (AS-OCT) in diverse ocular surface disorder (OSD) cohorts, exploring various anterior segment parameters and their accuracy in different disease groups. A total of 239 participants across six distinct OSD groups and healthy controls underwent nonmydriatic AS-OCT imaging using the Tomey CASIA 2 device. Anterior segment parameters including anterior chamber depth, width, angle metrics, corneal thickness, keratometry, lens vault, and others were meticulously assessed. Statistical analyses determined repeatability limits and coefficients of variation for each parameter within the different OSD cohorts. Repeatability for anterior chamber and corneal parameters remained consistent across all OSD groups, indicating minimal impact of ocular surface disease on accuracy. The coefficient of variation (CoV) for the trabecular iris-space area was about 20% for all cohorts. Ocular surface inflammation emerged as a key factor in dry eye, affecting immune-mediated and non-immune conditions alongside age-related ocular surface changes. While anterior chamber depth measurements showed variations, particularly in immune (CoV = 2.5%) and non-immune (CoV = 3.8%) OSD groups, parameters like anterior chamber width and angle to angle showed similar values among the cohorts. Keratometry measures remained stable despite OSD (CoV lower than 1%). The Tomey CASIA 2 demonstrated reliable repeatability for measuring anterior segment parameters in diverse OSD cohorts. Despite challenges posed by dry eye conditions, this technology holds promise in assessing OSD, suggesting potential clinical protocols similar to those in healthy controls.