Systematic bibliometric analysis of research hotspots and trends on the application of premium IOLs in the past 2 decades

AIM:To analysis of research hotspots and trends on the application of premium intraocular lens(PIOLs)in the past 2 decades.METHODS:The literature search was performed on the Web of Science and included PIOLs studies published between January 2000 and December 2022.The retrieved literature was collated and analyzed by R-tool’s Bibliometrix package,CitNetExplorer,CiteSpace and other software.RESULTS:A total of 1801 articles about PIOLs were obtained,most of which were published in Spain and the United States.The organization that published the most articles was the University of Valencia in Spain.Alió JL,and Montés-Micó R,from Spain were the most influential authors in this field.The Journal of Cataract and Refractive Surgery and Journal of Refractive Surgery were the core journals for this field;the top 10 cited articles mainly focus on postoperative satisfaction with multifocal intraocular lens(IOLs)and postoperative results of toric IOLs.Through the keyword analysis,we found that trifocal IOLs,astigmatism and extended depth of focus(EDoF)IOLs are the most discussed topics at present,and the importance of astigmatism and the clinical application of the new generation of PIOLs are the emerging research trends.CONCLUSION:Bibliometric analysis can effectively help to identify multilevel concerns in PIOLs research and the prevailing research trends in the realm of PIOLs encompass the adoption of EDoF IOLs,trifocal IOLs,and their respective Toric models.

Effect of the posterior corneal surface on total corneal astigmatism in patients with age-related cataract

AIM： To explore the effect of the posterior astigmatism on total corneal astigmatism and evaluate the error caused by substituting the corneal astigmatism of the simulated keratometriy （simulated K） for the total corneal astigmatism in age-related cataract patients. METHODS： A total of 211 eyes with age-related cataract from 164 patients （mean age： 66.8±9.0y, range： 45-83y） were examined using a multi-colored spot reflection topographer, and the total corneal astigmatism was measured. The power vector components J0 and J45 were analyzed. Correlations between the magnitude difference of the simulated K and total cornea astigmatism （magnitude differenceSimK-Tca）, anterior J0, and absolute meridian difference （AMD） between the anterior and posterior astigmatisms were calculated. To compare the astigmatism of the simulated K and total cornea both in magnitude and axial orientation, we drew double-angle plots and calculated the vector difference between the two measures using vector analysis. A corrective regression formula was used to adjust the magnitude of the simulated K astigmatism to approach that of the total cornea. RESULTS： The magnitude differenceSimK-Tca was positively correlated with the anterior corneal J0 （Spearman’s rho= 0.539; P〈0.001） and negatively correlated with the AMDR （Spearman’s rho=-0.875, P〈0.001）. When the anterior J0 value was larger than 1.3 D or smaller than -0.8 D, the errors caused by determining the total corneal astigmatism with the karatometric calculation tended to be greater than 0.25 D. An underestimation by 16% was observed for against the rule （ATR） astigmatism and an overestimation by 9% was observed for with the rule （WTR） astigmatism when ignoring the posterior measurements. CONCLUSION： Posterior corneal astigmatism should be valued for more precise corneal astigmatism management, especially for higher ATR astigmatism of the anterior corneal surface. We suggest a 9% reduction in the magnitude of the simulated K in eyes with WTR astigmatism, and a 16% addition of the magnitude of the simulated K in eyes with ATR astigmatism.

Comparison of immersion ultrasound and low coherence reflectometry for ocular biometry in cataract patients

AIM： To compare the results of axial length （AL） biometry in cataract eyes by three methods： immersion B-ultrasound （IB） biometry, immersion A-ultrasound （IA） biometry and optical low coherence reflectometry. METHODS： In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. RESULTS： Eighty eyes of 80 patients （39 men and 41 women） for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance （P=0.97）; the mean difference in AL measurements was -0.031 mm （P=0.26; 95%CI, -0.09 to 0.02）; linear regression showed an excellent correlation （r=0.98, P〈0.0001）. Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance （IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07）; linear regression showed an excellent correlation （IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96）; Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement （LoA）, -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. CONCLUSION： Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.

Long-term results of clear lens extraction combined with piggyback intraocular lens implantation to correct high hyperopia

AIM:To assess the refractive outcome of clear lensectomy combined with piggyback intraocular lens implantation in highly hyperopic patients.METHODS:This case review included 19 eyes of 10 patients with high hyperopia and axial length less than 21mm.Intraocular lens power was calculated for emmetropia using the Holladay II formula in 17 eyes,and SRK/T formula in 2 eyes following clear lens extraction and piggyback intraocular lens implantation.Patients were examined periodically over 24 months for visual acuity and spherical equivalent(SE).RESULTS:The mean postoperative SE at 24 months was 0.20±1.39D(range,-3.00 to 2.50D),better than preoperative 9.81±2.62D(range,+6.00 to +14.50D)(P【0.001).Five eyes had SE within±0.5D of emmetropia and 11 eyes within±1.00D at postoperative 24 months.The mean postoperative uncorrected visual acuity(UCVA) at 24 months was 0.60±0.36,significantly improved compared to preoperative 1.39±0.33(P【0.001).The mean best-corrected visual acuity(BCVA) at 24 months was 0.49±0.35,not statistically different compared to preoperative 0.38±0.30(P=0.34).Twelve eyes maintained and 1 gained 1 or more Snellen line of BCVA,4 eyes lost 1 line,and 2 eyes lost 2 lines at 24 postoperative months.Twelve eyes best-corrected near visual acuity (BCNVA) achieved J1 at postoperative 24 months compared to preoperative 7 eyes and the other 7 eyes better than J3.CONCLUSION:Clearlensextractioncombinedpiggyback intraocular lens implantation appears to be an effective procedure to correct high hyperopia but mild overcorrection and intralenticular opacification may require secondary procedure.

Anterior segment OCT application in quantifying posterior capsule opacification severity with varied intraocular lens designs

AIM:To evaluate the application of anterior segmentoptical coherence tomography(AS-OCT)in posterior capsule opacification(PCO)severity assessment and analyse the relationship between PCO severity and intraocular lens(IOL)characters.METHODS:PCO patients were prospectively recruited.Cross-sectional images of the anterior segment at horizontal and vertical meridians were acquired with AS-OCT.The area of the IOL-PC(posterior capsular)space and PCO severity(area,thickness,and density at 3 mm and 5 mm IOL optic regions)were measured.The relationship between PCO severity and visual acuity,comparisons of PCO severity and IOL-PC space using varied IOL designs were analysed.RESULTS:One hundred PCO eyes were enrolled.IOL-PC space,PCO thickness and area were positively correlated with axial length.In addition,PCO area and thickness were positively correlated with visual acuity when it was≤0.52 log MAR.The cut-off level of visual acuity should be 0.52 log MAR.With varied IOL designs,3-piece C haptic IOL showed a smaller PCO area and thickness than the 1-piece 3 haptic IOL and 1-piece 4 haptic IOL.PCO area and thickness values for an IOL with a diameter≤11.0 mm was greater than for an IOL with a diameter of 12.5 mm,and the differences were statistically significant.PCO area and thickness increased when IOL haptic angulation increased(from 0 to 12 degrees).CONCLUSION:In PCO eyes,cut-off level of visual acuity is 0.52 log MAR.With more severe PCO,visual acuity maybenot enough to describe the visual function impairment.PCO severity and IOL-PC space are significantly correlated with axial length and IOL design and material.