Evaluating keratometry and corneal astigmatism data from biometers and anterior segment tomographers and mapping to reconstructed corneal astigmatism.

BACKGROUND: To compare results from different corneal astigmatism measurement instruments; to reconstruct corneal astigmatism from the postimplantation spectacle refraction and toric intraocular lens (IOL) power; and to derive models for mapping measured corneal astigmatism to reconstructed corneal astigmatism. METHODS: Retrospective single centre study involving 150 eyes treated with a toric IOL (Alcon SN6AT, DFT or TFNT). Measurements included IOLMaster 700 keratometry (IOLMK) and total keratometry (IOLMTK), Pentacam keratometry (PK) and total corneal refractive power in 3 and 4 mm zones (PTCRP3 and PTCRP4), and Aladdin keratometry (AK). Regression-based models mapping the measured C0 and C45 components (Alpin's method) to reconstructed corneal astigmatism were derived. RESULTS: Mean C0 components were 0.50/0.59/0.51 dioptres (D) for IOLMK/PK/AK; 0.2/0.26/0.31 D for IOLMTK/PTCRP3/PTCRP4; and 0.26 D for reconstructed corneal astigmatism. All corresponding C45 components ranged around 0. The prediction models had main diagonal elements lower than 1 with some crosstalk between C0 and C45 (nonzero off-diagonal elements). Root-mean-squared residuals were 0.44/0.45/0.48/0.51/0.50/0.47 D for IOLMK/IOLMTK/PK/PTCRP3/PTCRP4/AK. CONCLUSIONS: Results from the different modalities are not consistent. On average IOLMTK/PTCRP3/PTCRP4 match reconstructed corneal astigmatism, whereas IOLMK/PK/AK show systematic C0 offsets of around 0.25 D. IOLMTK/PTCRP3/PTCRP4. Prediction models can reduce but not fully eliminate residual astigmatism after toric IOL implantation.

Systematic review for the development of a core outcome set for monofocal intraocular lenses for cataract surgery.

Introduction: The aim of the study was to define a core outcome set (COS) to be measured following cataract surgery for the postoperative evaluation of monofocal intraocular lenses (IOLs). Compared to current COSs, the present work provides updates considering the advances in the technology due to the development of new generation monofocal IOLs, which are characterized by a safety profile comparable to standard monofocal IOLs but with an extended range of intermediate vision. Methods: Healthcare professionals (ophthalmologist surgeons) and patients were involved in the selection of outcomes to be included in the COS, starting from a list of indicators retrieved from a systematic literature search. The search considered observational studies with both a retrospective or prospective design, case studies and classic randomized controlled trials (RCTs). A mixed methodology integrating a Delphi-driven and an expert panel approach was adopted to reach an agreement among clinicians, while patients were involved in the completion of a questionnaire. Results: The final COS included 15 outcomes. Eleven outcomes, all clinical, were considered for inclusion after a joint discussion among ophthalmologists; seven outcomes were linked to visual acuity, while the remaining to contrast sensitivity, refractive errors, aberrations and adverse events. Measurement metrics, method of aggregation and measurement time point of these outcomes were specified. The most important aspects for the patients were (1) quality of life after cataract surgery, (2) the capacity to perform activities requiring good near vision (e.g., reading), (3) spectacle independence, and (4) safety of movements without fear of getting hurt or falling (intermediate vision). Discussion: In a context with limited healthcare resources, it is important to optimize their use considering also the preferences of end-users, namely patients. The proposed COS, developed involving both ophthalmologists and patients, provides an instrument for the postoperative evaluation of different technologies in the context of monofocal IOLs, which can be used not only in clinical trials but also in clinical practice to increase the body of real-world evidence.

Accuracy of Nine Formulas to Calculate the Powers of an Extended Depth-of-Focus IOL Using Two SS-OCT Biometers.

PURPOSE: To evaluate the accuracy of nine formulas to calculate the power of a new extended depth-of-focus intraocular lens (EDOF IOL), the AcrySof IQ Vivity (Alcon Laboratories, Inc), using measurements from two optical biometers, the IOLMaster 700 (Carl Zeiss Meditec AG) and Anterion (Heidelberg Engineering GmbH). METHODS: After constant optimization, the accuracy of these formulas was analyzed in 101 eyes: Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, Olsen, RBF 3.0, and SRK/T. Both standard and total keratometry from the IOLMaster 700 and standard keratometry from the Anterion were used for each formula. RESULTS: Constant optimization provided slightly different values for the A-constant, which ranged between 118.99 and 119.16, depending on the formula and the optical biometer. According to the heteroscedastic test, within each keratometry modality the standard deviation of the SRK/T was significantly higher compared to that of the Holladay 1, Kane, Olsen, and RBF 3.0 formulas. The SRK/T formula provided less accurate results also when the absolute prediction errors were compared by Friedman test. According to McNemar's test with Holm corrections, statistically significant differences were found within each keratometry modality between the percentage of eyes with a prediction error within ±0.25 diopters obtained with the Olsen formula compared to the Holladay 1 and Hoffer Q formulas. CONCLUSIONS: Constant optimization remains a mandatory step to achieve the best outcomes with the new EDOF IOL: the same constant should not be used for all formulas and for both optical biometers. Different statistical tests revealed that older IOL formulas have lower accuracy compared to newer formulas. [J Refract Surg. 2023;39(3):158-164.].

Comparison of the new Hoffer QST with 4 modern accurate formulas.

PURPOSE: To investigate the new Hoffer QST (Savini/Taroni) formula (HQST) and compare it with the original Hoffer Q (HQ) and 4 latest generation formulas. SETTING: I.R.C.C.S.-G.B. Bietti Foundation, Rome, Italy. DESIGN: Retrospective case series. METHODS: Refractive outcomes of the HQST, Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, HQ, Kane, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in short (<22 mm) and long (>25 mm) axial length eyes. The SD of the prediction error (PE) was investigated using the heteroscedastic method. RESULTS: 1259 eyes of 1259 patients divided in a White group (n=696), implanted with the AcriSof SN60AT (Alcon Labs), and an Asian group (n=563), implanted with the SN60WF (Alcon Labs), were investigated. In the Asian group, the heteroscedastic method did not disclose any significant difference among the SD of the 4 modern formulas (range from 0.333 to 0.346 D), whereas the SD of the HQ formula (0.384 D) was significantly higher. Compared with the original HQ formula, in both White and Asian groups, the HQST formula avoided the mean myopic PE in short eyes and the mean hyperopic PE in long eyes. CONCLUSIONS: The new HQST formula was superior to the original HQ formula and reached statistical and clinical results comparable with those achieved by the BUII, EVO, Kane, and RBF formulas.

IOL Power Calculation in Eyes Undergoing Combined Descemet Membrane Endothelial Keratoplasty and Cataract Surgery.

PURPOSE: To assess the accuracy of different corneal powers for intraocular (IOL) power calculation in combined Descemet membrane endothelial keratoplasty (DMEK) and cataract surgery and investigate whether preoperative parameters correlate to the prediction error (PE). METHODS: This prospective case series involved patients with Fuchs endothelial dystrophy receiving combined DMEK and cataract surgery. Preoperatively, patients underwent optical biometry and anterior segment OCT (AS-OCT). AS-OCT measurements were repeated 6 months postoperatively, when final refraction was assessed. The PE was calculated using the preoperative average keratometry (Kave) measured by the optical biometer and User Group for Laser Interference Biometry (ULIB) constants. It was also calculated, after constant optimization, using the preoperative Kave from both devices and the total corneal power (TCP) measured by AS-OCT, as well as the postoperative Kave and TCP measured by AS-OCT. RESULTS: ULIB constants resulted in the highest hyperopic PE (P < .0001). Constant optimization improved the results, because the PE was zeroed out and the absolute PEs decreased. No significant difference was found among the Barrett Universal II, Emmetropia Verifying Optical 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas. Further improvement was achieved with the postoperative Kave and TCP, although the accuracy remained moderate. The PE based on preoperative corneal measurements was correlated to the amount of corneal flattening; the latter could be predicted by multiple linear regression accounting for anterior and posterior corneal radii (P = .0002) and was correlated to the preoperative anterior/posterior ratio. CONCLUSIONS: Constant optimization is beneficial for combined DMEK and phacoemulsification. Predicting postoperative corneal flattening may improve the results of IOL power accuracy. [J Refract Surg. 2022;38(7):435-442.].

Accuracy of newer intraocular lens power formulas in short and long eyes using sum-of-segments biometry.

PURPOSE: To analyze the accuracy of newer intraocular lens power formulas in long and short eyes measured using the sum-of-segments biometry. SETTING: Private practice, Lynwood, California. DESIGN: Retrospective observational study. METHODS: 595 patients scheduled for cataract surgery had their eyes measured using the sum-of-segments biometry. The expected residual refractions were calculated using Barrett Universal II (B II), Barrett True Axial Length (BTAL), Emmetropia Verifying Optical (EVO), Hill-RBF, Hoffer QST, Holladay 2, Holladay 2-NLR, K6, Kane, Olsen, PEARL-DGS, T2, and VRF formulas and compared with the traditional Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. RESULTS: In the 102 long eyes, all new formulas had a mean absolute error (MAE) equal or lower than the traditional formulas, ranging from 0.29 to 0.32 diopter (D). In the 78 short eyes, BTAL, EVO, Hoffer QST, K6, Olsen, and PEARL-DGS formulas had the lowest MAE (0.33 D, 0.33 D, 0.31 D, 0.36 D, 0.32 D, and 0.32 D, respectively), whereas all traditional formulas exceeded 0.36 D. CONCLUSIONS: All new formulas performed equal or better than the traditional formulas with the sum-of-segments biometry. The best overall results in the short and long eyes as well as in the very short and very long eyes were noted with the BTAL, EVO, Hoffer QST, K6, Olsen, and PEARL-DGS formulas, closely followed by the B II and Kane formulas.

Agreement of intraocular lens power calculation between 2 SS-OCT-based biometers.

PURPOSE: To assess agreement of measurements by 2 swept-source optical coherence tomography biometers and to evaluate the prediction error (PE) in intraocular lens power calculation with 7 formulas. SETTING: Tertiary public eye hospital. DESIGN: Consecutive observational. METHODS: Axial length (AL), keratometry (K), anterior chamber depth (ACD), lens thickness (LT), and corneal diameter (CD) were measured with the IOLMaster 700 (Biometer A) and Anterion (Biometer B). Agreement was quantified by the limits of agreement and concordance correlation coefficient (CCC). The PE, the median absolute error, and the mean absolute error of the Barrett Universal II, EVO 2.0, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T formulas were investigated after constant optimization. RESULTS: In 78 eyes from 78 patients, excellent agreement was obtained for AL (CCC >0.99), very good agreement for K, ACD, and LT (CCC >0.95), and strong agreement for CD (CCC >0.72). An additive offset of 0.07 mm was measured for ACD and LT whose mean values were higher with Biometer B (P < .001). No statistically significant difference was found between the PEs and their absolute values when comparing the results of each formula between the 2 biometers. CONCLUSIONS: Agreement of biometric measurements by the 2 biometers was high, although Biometer B provided higher mean values of ACD and LT by 0.07 mm. In cataract patients with normal eye length, measurements by the 2 biometers did not lead to different refractive outcomes with the 7 formulas investigated.

Comparison of different methods to calculate the axial length measured by optical biometry.

PURPOSE: To compare axial length (AL) measurements in long eyes by 2 swept-source optical coherence tomography (SS-OCT) biometers, one based on the group refractive index (IOLMaster 700, Zeiss) and the other based on sum of segments (Argos, Movu Inc.), and compare these measurements with previously published methods to optimize AL. SETTING: G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. DESIGN: Prospective case series. METHODS: AL was measured with both optical biometers in patients with myopia (AL > 24.0 mm) and compared with the values obtained with Wang-Koch adjustment, polynomial equations for the Holladay 1 and 2 formulas, and Cooke-modified AL (CMAL). RESULTS: In 102 eyes of 55 subjects, a statistically significant difference (P < .0001) was found among the 6 AL values. Posttest revealed that Argos measurements (26.90 ± 1.61 mm) were significantly lower compared with those provided by all methods (P < .001) but CMAL, whereas IOLMaster 700 measurements (27.01 ± 1.65) were higher (P < .001). No difference was found between the 2 Holladay equations. CMAL values did not reveal any difference compared with those of the Argos, but a proportional bias showed that in longer eyes, CMAL provided smaller values (P < .0001, r = -0.7221). AL overestimation by the IOLMaster 700 AL compared with the Argos was higher, the longer the eye was (P < .0001, r = 0.6959, r2 = 0.4842). CONCLUSIONS: The SS-OCT optical biometer based on the group refractive index overestimates AL compared with the device using segmented AL. CMAL provides the measurements closest to those of the device using segmented AL.

Immersion ultrasound biometry vs optical biometry.

PURPOSE: To compare axial length (AL) measurements obtained by optical biometry (OB) and immersion ultrasound (iUS) to investigate the agreement between the 2 techniques and how to use OB constants for eyes with AL by iUS. SETTING: Multicenter study. DESIGN: Retrospective observational case series. METHODS: Agreement between OB and iUS ALs was investigated in 4 subsets. Also, in a test database, the prediction error (PE) for iUS AL was assessed with 4 methods: (1) data-optimized constants; (2) user group for laser interference biometry (ULIB) constants with iUS biometry; (3) with recalibrated AL; and (4) ULIB A-constant - 0.23. RESULTS: A Combined 1970 eyes were measured with both OB and iUS biometry. OB mean AL was 0.0873 mm longer than iUS AL. The latter was made equivalent to OB ALs with this equation: Recalibrated iUS AL = 1.0228 × iUS AL - 0.4556. In a fifth database (n = 1079) with OB AL measurements only, after AL was artificially shortened by 0.0873 mm, the original A-constant had to be reduced by 0.23 to maintain a zero PE. In a sixth database (n = 127) with iUS AL, the original ULIB A-constant provided the poorest outcomes. Using either recalibrated iUS AL or ULIB A-constant - 0.23 zeroed out the mean PE and achieved the lowest median absolute error. CONCLUSIONS: AL measurements by iUS can be used with ULIB constants for OB by subtracting 0.23 from the A-constant; alternatively, the iUS AL may be recalibrated. The recalibrated iUS AL should be treated as AL measurements obtained by OB. It is longer than iUS AL in long eyes.

Comparison of Corneal Power Calculation by Standard Keratometry and Total Keratometry in Eyes With Previous Myopic FS-LASIK.

PURPOSE: To compare the accuracy of Total Keratometry (TK) and standard keratometry (K) with the IOLMaster 700 (Carl Zeiss Meditec) in evaluating the corneal refractive change in eyes with previous myopic femtosecond laser-assisted LASIK (FS-LASIK). METHODS: A series of consecutive patients who had undergone myopic FS-LASIK was prospectively enrolled. The refractive change in spherical equivalent (ΔSE) was defined as the difference between the preoperative target correction entered into the laser software and the postoperative cycloplegic refraction. The difference between the postoperative and the preoperative K (ΔK) and the difference between the postoperative and the preoperative TK (ΔTK) were compared to the ΔSE. Only the right eye of each patient was selected for the statistical analysis. RESULTS: Twenty-five eyes of 25 patients were enrolled. The mean ΔSE was -4.41 ± 1.68 diopters (D). The mean ΔK (-3.82 ± 1.60 D) revealed a statistically significant underestimation of the laser-induced refractive change (P < .0001), whereas the mean ΔTK (-4.36 ± 1.78 D) did not show any significant difference (P = .45). The difference between ΔK and ΔTK was statistically significant (P < .0001). Linear regression between the laser-induced refractive change and the individual difference between the postoperative K and TK disclosed a statistically significant relationship (r = -0.6930, r2 = 0.4803, P < .0001), thus revealing that higher refractive corrections increase the difference between the postoperative values of K and TK. CONCLUSIONS: TK does not underestimate the laser-induced corneal changes and can be considered a reliable option for intraocular lens power calculation after myopic excimer laser surgery. [J Refract Surg. 2021;37(12):848-852.].

Accuracy of New Intraocular Lens Power Calculation Formulas: A Lens Thickness Study.

PURPOSE: To investigate whether using lens thickness measurement as an optional input improves the refractive accuracy of four new generation formulas. METHODS: Consecutive patients scheduled for cataract surgery were enrolled. Preoperative biometry was performed with an OA-2000 optical biometer (Tomey). All patients received the same monofocal intraocular lens (AcrySof SN-60WF; Alcon Laboratories, Inc). The Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO), Kane, and Radial Basis Function (RBF) formulas were analyzed with and without the inclusion of lens thickness as an input. Postoperative refraction was measured at 1 month. The mean prediction error (PE), the median absolute error (MedAE), and the percentage of eyes with a PE within ±1.00 diopters (D) or less were calculated after constant optimization. RESULTS: The final analysis was performed on 169 eyes of 169 patients. Comparison of the mean PE, MedAE, and the percentage of eyes with a PE within ±0.25, ±0.50, ±0.75, and ±1.00 D resulting from each formula with and without lens thickness did not reveal any statistically significant difference. Cochran's Q test showed a statistically significant difference among formulas in the percentage of eyes with a PE of less than ±0.50 D (P = .042). However, Dunn's post-hoc test did not show any statistically significant difference between any pair of formulas. CONCLUSIONS: Lens thickness measurement did not improve the accuracy of the BUII, EVO, Kane, or RBF formulas. The RBF formula yielded the same results with and without lens thickness, thus making this input useless. [J Refract Surg. 2021;37(3):202-206.].

Crossing the Death Valley of publication process in cornea and ocular surface diseases: from abstracts presented at the Association for Research in Vision and Ophthalmology annual meeting to full-text manuscripts / Atravessando o Vale da Morte do processo de publicação sobre doenças da córnea e da superfície ocular: de resumos apresentados no Encontro Anual da Associação de Pesquisa em Visão e Oftalmologia até artigos completos

ABSTRACT Purpose: This study was conducted to analyze the profile and publication rate of abstracts in indexed journals presented in the cornea section at the Association for Research in Vision and Ophthalmology Annual Meeting and to further identify potential predictive factors for better outcomes. Methods: Abstracts accepted for presentation at the 2013 Association for Research in Vision and Ophthalmology Annual Meeting in the cornea section were sought via PubMed and Scopus to identify whether they had been published as full-text manuscripts. First author's name, time of publication, journal's name, and impact factor were recorded. A multivariate regression was performed to explore the association between variables and both the likelihood of publication and the journal's impact factor. A Kaplan-Meier analysis was performed to evaluate the time course of publication of abstracts. Results: Of the 939 analyzed abstracts, 360 (38.3%) were published in journals with a median impact factor of 3.4. The median time interval between abstract submission and article publication was 22 months. The multivariate analysis revealed that abstracts were more likely to be published if they were funded (OR=1.482, p=0.005), had a control group (OR=1.511, p=0.016), and had a basic science research scope (OR=1.388, p=0.020). The journal's impact factor was higher in funded studies (β=0.163, p=0.002) but lower in multicenter studies (β=-0.170, p=0.001). The Kaplan-Meier analyses revealed significant differences in the publication time distribution for basic science vs clinical abstracts (χ2=7.636), controlled vs uncontrolled studies (χ2=6.921), and funded vs unfunded research (χ2=13.892) (p<0.05). Conclusion: Almost 40% of Association for Research in Vision and Ophthalmology abstracts were published within 5 years from submission. Funding support, basic research scope, and controlled design were the determinants of better outcomes of publication.(AU)

RESUMO Objetivo: Analisar o perfil e a taxa de publicação em periódicos indexados de resumos apresentados na seção de córnea da reunião anual da Association for Research in Vision and Ophthalmology - ARVO, para identificar potenciais fatores preditivos com objetivo de obter melhores resultados. Métodos: Artigos que foram aceitos para apresentação no encontro anual da Association for Research in Vision and Ophthalmology - ARVO 2013 na seção de córnea foram pesquisados via PubMed e Scopus para identificar se haviam sido publicados como manuscritos com texto integral. Nome do primeiro autor, data de publicação, nome da revista e fator de impacto foram registrados. Foi feita uma regressão multivariada para estabelecer uma associação entre as variáveis e a chance de publicação e o fator de impacto da revista. Foi utilizado o método Kaplan-Meier para analisar o tempo da apresentação até a publicação dos artigos. Resultados: Dos 939 artigos analisados, 360 (38.3%) foram publicados em revistas com um fator de impacto médio de 3.4. O intervalo de tempo entre a submissão do resumo e a publicação do artigo teve como mediana 22 meses. Na análise multivariada, resumos tinham mais chance de publicação se tinham algum tipo de financiamento (OR=1.482, p=0.005), tinham grupo controle (OR=1.511, p=0.016) e estavam no âmbito da pesquisa científica básica (OR+1.388, p=0.020). O fator de impacto da revista era maior em estudos financiados (β=0.163, p=0.002) e mais baixo naqueles multicêntricos (β=-0.170, p=0.001). A análise Kaplan-Meier mostrou diferenças significativas na distribuição de tempo até a publicação de resumos de ciência básica vs clínicos (χ2=7.636), com grupo controle vs sem grupo controle (χ2=6.921) e financiados vs não financiados (χ2=13.892) (p<0.05). Conclusão: Aproximadamente 40% dos resumos apresentados no encontro da Association for Research in Vision and Ophthalmology - ARVO foram publicados dentro de 5 anos da submissão. Financiamento, pesquisa no âmbito da ciência básica e presença de grupo controle foram fatores determinantes para melhores resultados em relação à chance de publicação.(AU)

Crossing the Death Valley of publication process in cornea and ocular surface diseases: from abstracts presented at the Association for Research in Vision and Ophthalmology annual meeting to full-text manuscripts.

PURPOSE: This study was conducted to analyze the profile and publication rate of abstracts in indexed journals presented in the cornea section at the Association for Research in Vision and Ophthalmology Annual Meeting and to further identify potential predictive factors for better outcomes. METHODS: Abstracts accepted for presentation at the 2013 Association for Research in Vision and Ophthalmology Annual Meeting in the cornea section were sought via PubMed and Scopus to identify whether they had been published as full-text manuscripts. First author's name, time of publication, journal's name, and impact factor were recorded. A multivariate regression was performed to explore the association between variables and both the likelihood of publication and the journal's impact factor. A Kaplan-Meier analysis was performed to evaluate the time course of publication of abstracts. RESULTS: Of the 939 analyzed abstracts, 360 (38.3%) were published in journals with a median impact factor of 3.4. The median time interval between abstract submission and article publication was 22 months. The multivariate analysis revealed that abstracts were more likely to be published if they were funded (OR=1.482, p=0.005), had a control group (OR=1.511, p=0.016), and had a basic science research scope (OR=1.388, p=0.020). The journal's impact factor was higher in funded studies (ß=0.163, p=0.002) but lower in multicenter studies (ß=-0.170, p=0.001). The Kaplan-Meier analyses revealed significant differences in the publication time distribution for basic science vs clinical abstracts (χ2=7.636), controlled vs uncontrolled studies (χ2=6.921), and funded vs unfunded research (χ2=13.892) (p<0.05). CONCLUSION: Almost 40% of Association for Research in Vision and Ophthalmology abstracts were published within 5 years from submission. Funding support, basic research scope, and controlled design were the determinants of better outcomes of publication.

Repeatability of total Keratometry and standard Keratometry by the IOLMaster 700 and comparison to total corneal astigmatism by Scheimpflug imaging.

OBJECTIVES: We aimed (1) to assess the repeatability of Total Keratometry (TK) and standard keratometry (K) measurements, as provided by the IOLMaster 700 (Carl Zeiss Meditec), and (2) to compare the corneal astigmatism measured by TK to the total corneal astigmatism (TCA) measured by a Scheimpflug camera (Pentacam AXL, Oculus). METHODS: Two groups of patients were prospectively enrolled: Group A included previously unoperated eyes undergoing cataract surgery, and Group B eyes with previous myopic corneal excimer laser surgery. TK and K were measured three times by the same examiner. Repeatability was assessed based on the within-subject standard deviation (Sw), test-retest variability, coefficient of variation and intraclass correlation coefficient (ICC). In Group A, TCA was measured once and compared to TK astigmatism. Vector analysis was performed according to Næser. RESULTS: In Group A (69 eyes) the mean K and TK were, respectively, 43.14 ± 1.37 D and 43.18 ± 1.37 D. In Group B (51 eyes) the mean K and TK were, respectively, 40.14 ± 2.20 D and 39.71 ± 2.35 D. The repeatability of the average K and TK was high (Sw < 0.10D). All measurements revealed an ICC > 0.9. For most measurements the variance of K and TK did not show any statistically significant difference either within groups or between groups. Vectors KP(45) were significantly different between TK astigmatism and TCA. CONCLUSIONS: TK measurements offer high repeatability in unoperated and post-excimer laser surgery eyes. TK astigmatism and TCA measurements could not be considered interchangeable.

Choroidal vascular changes after encircling scleral buckling for rhegmatogenous retinal detachment.

BACKGROUND/OBJECTIVES: There is an ongoing debate on whether encircling scleral buckling (SB) procedure for the treatment of rhegmatogenous retinal detachment (RRD) may cause an impairment in choroidal blood flow. The aim of this study was to compare choroidal vascularity index (CVI) and subfoveal choroidal thickness (CT) between eyes that had undergone encircling SB with unoperated fellow eyes (FEs). SUBJECTS/METHODS: Thirty patients treated with encircling SB for unilateral RRD were included. Demographic and clinical characteristics as well as enhanced depth imaging-optical coherence tomography scans were retrospectively collected. Images were binarised using ImageJ software, total choroidal area along with luminal and stromal area (respectively, TCA, LA and SA) were segmented and the CVI was computed as the ratio of LA/TCA. In addition, CT was evaluated. RESULTS: The mean follow-up interval between surgery and examination was 25.5 ± 16.8 months. Choroidal thickness, TCA, LA and SA were significantly increased in the operated eyes compared to FEs (respectively, 271.7 ± 78.0 µm vs. 238.5 ± 83.4, P = 0.001; 1.804 ± 0.491 mm2 vs. 1.616 ± 0.496, P = 0.001; 1.199 ± 0.333 mm2 vs. 1.067 ± 0.337, P < 0.001 and 0.605 ± 0.171 mm2 vs. 0.550 ± 0.171, P = 0.001). Conversely, CVI did not significantly differ between the two groups (66.4 ± 3.6 vs. 65.9 ± 3.2, P = 0.490). CONCLUSIONS: In conclusion, eyes treated with encircling SB for RRD presented increased LA, SA and CT compared with FEs, but showed no difference in CVI.

Recent developments in intraocular lens power calculation methods-update 2020.

For many decades only a few formulas have been available to calculate the intraocular lens (IOL) power for patients undergoing cataract surgery: the Haigis, Hoffer Q, Holladay 1 and 2 and SRK/T. In recent years, several new formulas for IOL power calculation have been introduced with the aim of improving the accuracy of refraction prediction in eyes undergoing cataract surgery. These include the Barrett Universal II, the Emmetropia Verifying Optical (EVO), the Kane, the Næser 2, the Olsen, the Panacea, the Pearl DGS, the Radial Basis Function (RBF), the T2 and the VRF formulas. Although most of them are unpublished so that their structure is unknown, we give an overview of each formula and report the results of the studies that have compared them. Their performance in short and long eyes is provided and a special focus is given on the issue of segmented axial length, which is a promising method to obtain more accurate outcomes in short and long eyes. Here, the group refractive index originally developed for the IOLMaster may not represent the best method to convert the optical path length into a physical distance. The issue of posterior and total corneal astigmatism (TCA) is discussed in relation to toric IOLs; the latest formulas for toric IOLs and their results are also reported.

Outcomes of IOL power calculation using measurements by a rotating Scheimpflug camera combined with partial coherence interferometry.

PURPOSE: To evaluate the accuracy of the measurements provided by a Scheimpflug camera combined with partial coherence interferometry for intraocular lens (IOL) power calculation. SETTING: I.R.C.C.S.-G.B. Bietti Foundation, Rome, Italy. DESIGN: Prospective case series. METHODS: Consecutive patients scheduled for cataract surgery were enrolled. Preoperative biometry was performed with a Pentacam AXL. All patients received the same IOL (AcrySof SN60WF). Measurements were entered into the following formulas: Barrett Universal II, Emmetropia Verifying Optical 2.0, Haigis, Hoffer Q, Holladay 1, Holladay 2 with axial length adjustment, Kane, Ladas Super Formula (LSF) 2.0, Næser 2, Pearl-DGS, SRK/T, T2, and VRF. When refraction was measured at 1 month postoperatively, the mean prediction error (PE), the median absolute error (MedAE), and the percentage of eyes with a PE within ±0.25, ±0.50, and ±1.00 diopter (D) were calculated after constant optimization. RESULTS: Ninety-one eyes of 91 patients were analyzed. Comparison of the mean PE and MedAE did not reveal any statistically significant difference. However, the Pearl DGS formula achieved the lowest MedAE (0.19 D), followed by the LSF 2.0 (0.22). Twelve of the 13 formulas obtained a PE within ±0.50 D in at least 80% of eyes (range 80%-87%) and 7 of them in at least 85%. Twelve formulas yielded a PE within ±0.25 D in at least 50% of eyes (range 51%-64%). CONCLUSIONS: All the investigated formulas performed well using the Pentacam AXL measurements. The newest Pearl DGS formula version and LSF 2.0 showed promising results.

Dry Eye Disease and Tear Cytokine Levels-A Meta-Analysis.

Background-It is recognized that inflammation is an underlying cause of dry eye disease (DED), with cytokine release involved. We systematically reviewed literature with meta-analyses to quantitatively summarize the levels of tear cytokines in DED. Methods-The PubMed, Embase, Web of Science, Ovid, Cochrane, and Scopus databases were reviewed until September 2019, and original articles investigating tear cytokines in DED patients were included. Differences of cytokines levels of DED patients and controls were summarized by standardized mean differences (SMD) using a random effects model. Study quality was assessed by applying Newcastle-Ottawa-Scale and the GRADE quality score. Methods of analytical procedures were included as covariate. Results-Thirteen articles investigating 342 DED patients and 205 healthy controls were included in the meta-analysis. The overall methodological quality of these studies was moderate. Systematic review of the selected articles revealed that DED patients had higher tear levels of interleukin (IL)-1ß, IL-6, chemokine IL-8, IL-10, interferon-γ, IFN-γ, and tumor necrosis factor-α, TNF-α as compared to controls. Evidence was less strong for IL-2 and IL-17A. Conclusions-Data show that levels of tear cytokines in DED and control display a great variability, and further studies of higher quality enrolling a higher number of subjects are needed, to define a cut-off value.