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Background: We evaluated whether the best‐fit intraocular lens (IOL) power formula for the first operated eye (BF1) was also the most accurate formula for the second eye. Methods: This was a retrospective study of 152 patients who underwent uncomplicated delayed bilateral cataract surgery with a minimum delay of 3 weeks using only one 1‐piece IOL (HOYA, Vivinex) at the Medical University of Vienna, Austria. Seven different formulae (Barrett Universal II, Castrop, Haigis, Hoffer Q, Holladay 1, Kane, and SRK/T) were investigated to test the formula selection approach with regard to the calculated mean and median absolute prediction errors (MAE/MedAE). Results: The mean intraindividual difference in axial length was 0.2 mm (±0.3 mm). BF1 coincided with the best‐fit formula for the second eye (BF2) in 56% of patients (p < 0.05). Using BF1 for the second eye led to a lower MedAE (0.22 dioptre, D) than using a formula at random (0.33 D) and was less accurate than using the best‐fit formula for each eye separately (0.1 D). The MedAEs of all formulae were generally low, ranging from 0.28 to 0.35 D. Conclusion: Using BF1 for the second eye led to a lower MedAE than the random selection of a formula. Therefore, BF1 can be used for the second eye if the surgeon is unsure of the choice of formula. [ABSTRACT FROM AUTHOR]

Background To evaluate the biometric factors associated with the accuracy of intraocular lens power predictions for cataract surgery in primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) eyes. Design Cross-sectional study Participants This study included 103 PAC or PACG patients who had undergone cataract surgery. Methods All participants underwent anterior-segment optical coherence tomography preoperatively. Two novel biometric factors - the relative lens vault (the ratio of lens vault to anterior vault) and the anterior vault (the sum of lens vault and anterior chamber depth) - were measured using customized software. The powers of the implanted intraocular lens and the actual postoperative refractive errors were compared. The mean refractive error and the median absolute error were calculated and compared using repeated measures ANOVA and Wilcoxon matched-pairs signed-rank test. The biometric factors associated with the postoperative refractive error were investigated by multivariate regression analysis. Main Outcome Measures Preoperative anterior-segment biometric factors, difference between predicted and actual postoperative refraction. Results The Haigis, Hoffer Q and SRK/T formulas all showed a slight tendency toward resultant hyperopia, respectively ( P < 0.001, P = 0.05, P = 0.003). The Hoffer Q formula had the least prediction error ( P < 0.001). In the multivariate regression analysis, the relative lens vault was the only independent factor predicting postoperative refractive error ( β = 0.392, P = 0.011). Conclusion Intraocular lens power predictions for cataract surgery in PAC or PACG patients can be inaccurate. Such results might be associated with anterior-segment biometric factors. Preoperative relative lens vault appears to be a significant factor predicting refractive outcome after cataract surgery in patients with PAC or PACG. [ABSTRACT FROM AUTHOR]

Background To evaluate the accuracy of predicted refraction using multifocal intraocular lenses ( IOLs) with power calculation based on two biometric devices and multiple IOL power calculation formulas. Design A retrospective study conducted in a private practice ophthalmology clinic. Participants Seventy-three eyes of 48 patients were evaluated. Methods Consecutive cases of eyes that had undergone successful cataract surgery with an implantation of a multifocal IOL ( SN6 AD1, Alcon Laboratories, Inc., Fort Worth, TX, USA) by a single surgeon were enrolled. Patients were meticulously screened for suitability for a multifocal IOL implantation according to our clinic guidelines. Two biometric measurement devices ( IOLMaster-500 [ Carl Zeiss Meditec AG, Jena, Germany] and Lenstar- LS900 [ Haag- Streit AG, Koeniz, Switzerland]) were used under strict validation criteria to evaluate the predicted refraction errors for the Holladay 1, SRK/ T, Hoffer Q, Haigis, Holladay 2, Barrett Universal II and Olsen formulas. Main Outcome Measures Predicted refractive sphere equivalent ( RSE) errors. Results The measurements obtained from the two biometric devices were highly correlated. The standard deviation of the error in predicted RSE and the median absolute error were similar for the IOLMaster and the Lenstar devices using all formulas, ranging from 0.27 dioptres ( D) to 0.31 D and from 0.15 D to 0.21 D, respectively. A high percentage of eyes had an error in predicted RSE within ±0.5 D from target refraction, ranging from 86.3% to 93.2%. Conclusions High accuracy can be achieved in multifocal IOL power calculations by appropriate patient selection, precise biometry and appropriate IOL calculation formulas. [ABSTRACT FROM AUTHOR]

Purpose: To report the value of dual biometry in the detection of biometry errors. Methods: Study 1: retrospective study of 224 consecutive cataract operations. The intraocular lens power calculation was based on immersion biometry. Study 2: immersion biometry was compared with optical coherence biometry (OCB) in terms of axial length, anterior chamber depth, keratometry readings and the recommended lens power to achieve emmetropia. Study 3: prospective study of 61 consecutive cataract operations. Both immersion and OCB were performed, but lens power calculation was based on the latter. Results: Study 1: 115 (86%), 101 (75.4%), 90 (67.2%) and 50 (37.3%) of postoperative spherical equivalents were within ±1.5 dioptres (D), ±1.25 D, ±1 D and ±0.5 D of the target, respectively. Study 2: excellent agreement between axial length readings, anterior chamber depth readings and keratometry readings by immersion biometry and OCB was observed (reflected in a mean bias of −0.065 mm, −0.048 mm and +0.1803 D, respectively, in association with OCB). Agreement between the lens power recommended by each technique to achieve emmetropia was poor (mean bias of +1.16 D in association with OCB), but improved following appropriate modification of lens constants in the Accutome A-scan software (mean bias with OCB = −0.4 D). Study 3: 37 (92.5%) and 23 (57.5%) of operated eyes achieved a postoperative refraction within ±1 D and ±0.5 D of target, respectively. Conclusion: Systematic errors in biometry can exist, in the presence of acceptable postoperative refractive results. Dual biometry allows each biometric parameter to be scrutinized in isolation, and identify sources of error that may otherwise go undetected. [ABSTRACT FROM AUTHOR]

Background: The ability to perform biometry accurately on a dilated pupil can greatly facilitate the efficiency of a cataract service as it can be done on the day of surgery. The purpose of this study was to assess the repeatability of axial length (AL) calculations in undilated pupils and measure the difference in predicted and actual refractive outcomes in dilated pupils compared with undilated pupils. Methods: First, intraobserver repeatability was assessed by taking two consecutive recordings of AL using applanation A-scan ultrasonography in undilated pupils in 21 eyes. The mean AL for each eye was compared with a measurement made following pupil dilatation. Second, we audited the mean spherical equivalent refractive errors following routine cataract surgery in 38 patients with undilated pupils and 36 patients with dilated pupils. Results: The mean difference in intraobserver measurements was −0.05 mm (standard deviation [SD] 0.15) with pupils undilated. Following pupil dilatation, the mean dilated AL differed from the mean undilated AL reading by only 0.03 mm ( P > 0.05). The mean differences between planned and actual refractive error were 0.71D (SD 0.54) and 0.55D (SD 0.41) in dilated and undilated patients, respectively. This was not statistically significant ( P > 0.05). The range of differences between target and actual refraction was −1.45D to 2.70D for undilated patients and −1.88D to 1.18D in dilated patients. Conclusion: Although there was a greater spread of postoperative refractive errors in the dilated group, there were no statistically or clinically significant differences in postoperative refractive errors between the two categories of patients. Our study shows that applanation biometry may be safely performed for the purpose of cataract surgery after pupil dilatation. [ABSTRACT FROM AUTHOR]