Modern Formulas Research Articles

Modern Approaches to Achieving Control over Common Health Disorders in Infants: the Effectiveness of Extensively Hydrolyzed and Amino Acid Formulas

Proper nutrition of the mother and baby is the most important condition for the development and health of the child. It is the first 1000 days of a child’s life that are critical for neuroontogenesis, the formation of further abilities to acquire and improve various skills, and to learn successfully. It is the first 1000 days of a child’s life that are critical for neuroontogenesis, the formation of further abilities to acquire and improve various skills, and to learn successfully. Breast milk is the “gold standard” of nutrition for all newborns, including children with functional digestive disorders and food allergies. Supporting and promoting adherence to breastfeeding in the first 6 months of a child’s life are the most important tasks for all medical professionals providing medical care to children. The most common pathological conditions among children of the first year of life are functional digestive disorders and manifestations of food allergies, in which diet therapy is the main type of treatment. In situations where breast milk is not available to such an infant, it is important to make the right choice of formula. Modern formulas for artificial feeding of newborns and infants have a number of useful properties due to the features of the composition, which bring them as close as possible to breast milk, specially designed to provide adequate nutrition and simultaneously perform therapeutic tasks.

Breast milk oligosaccharides are the most essential ingredient in breast milk, affecting the health of infants: A review

Breastfeeding remains the “gold standard” of nutrition for children in the first years of life. However, factors such as hypogalactia, maternal stress, health problems and simply an unwillingness to breastfeed deprive the baby of breast milk (BM) and challenge pediatricians to choose an alternative food for the baby. The BM composition is complex, dynamic, and of scientific interest, and the attention of most scientists is directed to BM oligosaccharides (BMOs). Many benefits of BMOs have been proven in relation to the child's health, including the formation of the intestinal microbiota, maturation of the immune response, contribution to the barrier function of the intestine, and protection against pathogens. In the absence of breastfeeding, modern formulas containing BMOs can be used. The addition of a combination of 5 BMOs is a promising and effective approach to maintaining the overall health of formula-fed infants.

Update on intraocular lens formulas.

This review aims to discuss recent advances in intraocular lens (IOL) power calculation, including newly introduced formulas, classification updates, comparative analyses between formulas, and emerging trends in the field. A significant number of modern IOL power calculation formulas have become available, incorporating both established and novel concepts such as artificial intelligence and ray tracing. A revised classification system has been introduced, reflecting the underlying principles of each formula. Recent comparative studies demonstrate the excellent refractive outcomes achievable with modern formulas. Emerging trends, such as the use of sum-of-segments axial length and the incorporation of measured posterior corneal data, hold promise for refining predictions in cases of extreme axial lengths and nonphysiological corneas, respectively. Advances in optimization and analytical methods also have the potential to further enhance refractive results. The field of IOL power calculation is continually evolving through iterative improvements in formula design, driven by new technologies, advanced instrumentation, and innovative analytical approaches. These advancements enable excellent refractive outcomes, even in atypical eyes.

IOL calculation using six formulas in children undergoing lens extraction and primary IOL implantation with and without posterior optic capture.

To evaluate formulas for intraocular lens (IOL) calculation in children undergoing lens extraction and IOL implantation. Retrospective, consecutive case series at the Department of Ophthalmology, Goethe University Frankfurt, Germany. We included eyes that received lens extraction and IOL implantation (SN60AT, Alcon, Fort Worth, TX) due to congenital or juvenile cataract. Preoperative assessments included biometry (IOLMaster 500/700, Carl Zeiss Meditec, Germany). To evaluate the measurements, we compared the mean prediction error (MPE), mean and median absolute prediction error (MAE, MedAE) of six different formulas, and number of eyes within ± 0.5, ± 1.0, ± 2.0D of target refraction. Postoperative spherical equivalent was measured by retinoscopy 4-12 weeks after surgery. 66 eyes matched our inclusion criteria with a mean age of 6.3 years ± 3.2. MedAE was lowest in SRK/T (0.55D ± 1.08) followed by Holladay I (0.75D ± 1.00), EVO 2.0 (0.80D ± 0.89), Barrett Universal II (BUII, 0.86D ± 1.00), Hoffer Q (0.97 D ± 0.94), and Haigis (1.10D ± 0.95). Regarding eyes within ± 0.5D SRK/T (45.5.%, 30 eyes) performed best, followed by Holladay I (36.4%, 24 eyes), EVO 2.0 and BUII (each 34.8%, 23 eyes). There was a myopic shift seen in all formulas (MPE: -0.21 to -0.90D). Using modern formulas, or even AI formulas, for IOL calculation in children's eyes does barely improve predictability of the postoperative refraction. A myopic shift can be found for all formulas. However, specific formulas like SRK/T seem to better anticipate this.

Comparative accuracy of intraocular lens power calculation formulas when targeting myopia

PurposeThis study aims to compare the accuracies of intraocular lens (IOL) power calculation formulas when targeting myopia versus emmetropia. MethodsA total of 450 patients were included, with 225 patients targeting emmetropia and 225 patients aiming for approximately −2.0 diopters of myopia. This retrospective analysis utilized data from a single eye of each patient, with preoperative biometric measurements obtained using the IOL Master 700. The study considered established formulas such as Haigis, Hoffer Q, Holladay 1, Holladay 2, and SRK/T, as well as modern formulas including Barrett Universal II, Cooke K6, EVO 2.0, Hill-RBF, Hoffer QST, Kane, Olsen, and PEARL-DGS. Statistical analyses, including Friedman test and post hoc analysis, were employed to compare the accuracy of each IOL power calculation formula between the two groups. Additionally, a multiple regression analysis was conducted to identify variables influencing the accuracy of intraocular lens power calculation formulas. ResultsIn targeting myopia, all IOL formulas tended to exhibit a greater refractive error compared to when targeting emmetropic eyes. Notably, the Haigis, SRK/T, and Holladay 2 formulas were found to be highly influenced by this trend, while the modern formulas were less affected. ConclusionThe accuracy of IOL power calculation formulas diminishes when targeting myopia in comparison to emmetropia. However, the modern formulas appear less susceptible to this trend. Consequently, when aiming for myopia, the use of the modern formulas is recommended for enhanced accuracy in IOL power calculation.

Accuracy of Modern Intraocular Lens Formulas in Highly Myopic Eyes Implanted With Plate‐Haptic Intraocular Lenses

To evaluate the predictive accuracy of modern intraocular lens (IOL) formulas and axial length (AL) adjusted traditional IOL formulas, including Wang-Koch and Cooke-modified AL (CMAL) method, in long eyes with plate-haptic IOLs, and to compare refractive prediction error variances with C-loop IOLs. Retrospective consecutive case series study. Data from 391 eyes with Zeiss 509 M and 302 eyes with Alcon SN6CWS implants in highly myopic patients, following cataract surgery from January 2019 to November 2023, were collected. One eye per patient was selected. Predictive outcomes of 15 modern formulas (Barrett Universal II (BU II), Cooke K6 (K6), Emmetropia Verifying Optical (EVO) 2.0, Hoffer-QST, Kane, Karmona, Ladas AI, Naeser 2, Olsen, Pearl-DGS, Radial Basis Function (RBF) 3.0, T2, VRF-G, Zhu-Lu, and Z-Calc) and 4 traditional IOL formulas (Haigis, Hoffer Q, Holladay 1, and SRK/T) with AL adjusted methods, were evaluated. The mean prediction error, mean absolute prediction error (MAE), root-mean-square absolute prediction error (RMSAE) and the proportions of eyes with PEs within ±0.25 Diopter (D), ±0.50 D, ±0.75 D, and ±1.00 D were analyzed. Top 10 RMSAE-ranked formulas underwent further subgroup analysis based on AL, anterior chamber depth (ACD), and keratometry (K). For the 509 M group, RMSAE ranking for the top 10 IOL formulas were the RBF 3.0 (0.432), Zhu-Lu (0.436), Olsen (0.436), EVO 2.0 (0.437), Pearl-DGS (0.447), K6 (0.452), VRF-G (0.454), Naeser 2 (0.464), Haigis-CMAL (0.465) and Karmona (0.477). Karmona and Naeser 2 showed poorer performance in the extremely long AL and steep K subgroups, respectively (p ≤ 0.042). Haigis-CMAL accuracy was significantly lower in shallow ACD and flat K subgroups (P ≤ .045). The SN6CWS group showed significantly lower MAE and RMSAE compared to the 509 M group for the BU II, EVO 2.0, Hoffer-QST, Kane, Pearl-DGS, and Zhu-Lu formulas (P ≤ .024). In long eyes with plate-haptic IOLs, RBF 3.0 performed best, closely followed by Zhu-Lu, Olsen, and EVO 2.0; Karmona and Naeser 2 are discouraged for extreme AL and steep K conditions, respectively; Haigis-CMAL is not suggested for shallow ACD and flat K cases. Refractive outcomes in eyes implanted with a C-loop design IOL were more accurate than for those implanted with a plate-haptic design, for most tested formulas.

Клинический случай факоэмульсификации катаракты после термокератопластики в анамнезе

Purpose. To present a clinical case of cataract phacoemulsification in a patient with a thermokeratoplasty in anamnesis. Material and methods. Patient M., went to the clinic with complaints of decreased vision, “fog” in front of both eyes, especially in front of the right one. In the anamnesis 30 years ago, she had thermokeratoplasty for high degree hypermetropia (+8.00D) in both eyes. Due to the existing complaints and the presence of cataracts in both eyes, cataract phacoemulsification was performed with the implantation of toric IOLs in both eyes. Results. When evaluating the results in the longterm postoperative period (1 year after surgery), it was revealed that despite the difficulties that the surgeon faces when calculating intraocular lenses in patients after keratorefractive operations, we managed to achieve high visual acuity. Conclusions. The presented clinical case indicates that the measurement of the refractive power of the cornea using a modern scanning keratotopograph, the axial length of the eye using a noncontact biometer, the use of modern formulas for calculating the IOL, as well as the experience of an ophthalmic surgeon, allow achieving high functional results in the rehabilitation of patients with this pathology. Keywords: thermokeratoplasty, phacoemulsification of cataract, toric intraocular lens

Supplemented Infant Formula and Human Breast Milk Show Similar Patterns in Modulating Infant Microbiota Composition and Function In Vitro.

The gut microbiota of healthy breastfed infants is often dominated by bifidobacteria. In an effort to mimic the microbiota of breastfed infants, modern formulas are fortified with bioactive and bifidogenic ingredients. These ingredients promote the optimal health and development of infants as well as the development of the infant microbiota. Here, we used INFOGEST and an in vitro batch fermentation model to investigate the gut health-promoting effects of a commercial infant formula supplemented with a blend containing docosahexaenoic acid (DHA) (20 mg/100 kcal), polydextrose and galactooligosaccharides (PDX/GOS) (4 g/L, 1:1 ratio), milk fat globule membrane (MFGM) (5 g/L), lactoferrin (0.6 g/L), and Bifidobacterium animalis subsp. lactis, BB-12 (BB-12) (106 CFU/g). Using fecal inoculates from three healthy infants, we assessed microbiota changes, the bifidogenic effect, and the short-chain fatty acid (SCFA) production of the supplemented test formula and compared those with data obtained from an unsupplemented base formula and from the breast milk control. Our results show that even after INFOGEST digestion of the formula, the supplemented formula can still maintain its bioactivity and modulate infants' microbiota composition, promote faster bifidobacterial growth, and stimulate production of SCFAs. Thus, it may be concluded that the test formula containing a bioactive blend promotes infant gut microbiota and SCFA profile to something similar, but not identical to those of breastfed infants.

Cataract Outcomes Following Scleral Buckle Surgery for Retinal Detachment.

To investigate refractive, visual, and safety outcomes of cataract surgery performed after scleral buckling (SB) for retinal detachment (RD). A chart review at an academic medical center identified eyes with history of SB followed by subsequent cataract extraction between 2010 and 2022. Eyes with less than 3 weeks follow-up, silicone oil at time of biometry measurement, previous cornea surgery, or co-existing pathology impacting refractive outcomes were excluded. Predicted postoperative spherical equivalents (SE) were calculated with the Barrett Universal II (BU2), Kane, and SRK/T formulas for the implanted intraocular lens (IOL), and complications occurring within 1 year of surgery were abstracted. Sixty eyes of 60 patients met criteria for inclusion, and 40 (66.7%) had postoperative refraction recorded. Absolute prediction errors were 0.49, 0.45, and 0.52D with BU2, Kane, and SRK/T, respectively. Actual postoperative refraction was within 0.5 and 1.0 D of predicted in 26 (65.0%) and 36 (90.0%) using BU2, 23 (58%) and 37 (93%) using Kane, and 21 (52.5%) and 36 (90.0%) using SRK/T. In eyes with macula-on RD, corrected distance visual acuity (CDVA) of logMAR 0.301 (≈20/40) and logMAR 0.544 (≈20/70) or better was achieved in 12 (75.0%) and 15 (93.8%) of eyes. For macula-off RD eyes, these proportions were 19 (63.3%) and 24 (80.0%), respectively. Posterior capsular opacification requiring Nd: YAG capsulotomy was the most frequent complication in 30 (56.7%) eyes. Refractive outcomes of cataract surgery following SB may be modestly reduced, even when using modern formulas. Nevertheless, cataract surgery in this population results in favorable visual outcomes.

Результаты имплантации монофокальной интраокулярной линзы Clareon с автоматизированной системой доставки AutonoMe (один год наблюдений)

Material and methods. The short- and long-term results of phacoemulsification with implantation of 700 Clareon intraocular lenses (IOL) preloaded into disposable pneumatic AutonoMe delivery systems were studied. The optical power of the IOL was calculated using the Verion system using modern formulas for emmetropia. Functional and refractive results, surgical and postoperative complications were assessed. Results. Of the 700 Clareon IOL implantations performed, 693 (99.0%) were without complications; complications occurred in 7 (1.0%) eyes. By 12 months of observation, BCDVA and UCDVA increased from 0.15±0.03 to 0.65±0.09 and from 0.31±0.04 to 0.76±0.12 (p<0.05), respectively. Refraction of the target was achieved in 90% of patients. The loss of endothelial cells from the baseline level was 4.8%. In all patients, the optical part of the IOL remained stably transparent, no glistening phenomena were observed in any case; the haptic component of the IOL provided a stable correct central position of the IOL in the capsule bag. Secondary cataract developed in 22/605 (3.6%) eyes, which required dissection in 19/605 (3.1%) eyes. Conclusion. The new monofocal intraocular lens Clareon is high-tech and can be widely used in clinical practice. The new automated pneumatic delivery system AutonoMe is efficient and safe. Key words: phacoemulsification, Clareon, automatic IOL delivery system, glistening, secondary cataract

Особенности факоэмульсификации катаракты и расчета ИОЛ у пациентов с гиперметропией высокой степени

Despite the fact that phacoemulsification is a standard operation, in patients with high hypermetropia, this procedure may be accompanied by complications associated with a short axial axis of the eyeball, a small anterior chamber, as well as IOL calculation errors. Purpose. To evaluate the results of cataract surgical treatment and the accuracy of IOL calculation in patients with high-grade hypermetropia. Materials and methods. 34 patients (49 eyes) with high-grade hypermetropia who underwent cataract surgery with IOL implantation under observation were included. The comparison of uncorrected (UCVA) and corrected (BCVA) visual acuity, spherical refraction equivalent, IOP before surgery, at discharge, 1 and 6 months after surgery was carried out. Results. There was an increase in UCVA to 0.47 ± 0.13 and BCVA to 0.64 ± 0.21, as well as a decrease in the refractive index to –0.03 ± 0.29 in the postoperative period. The average IOP values after surgery in this sample of patients decreased from 14.45 ± 3.40 to 12.83 ± 5.04, and remained stable throughout the follow-up period. However, a significant refractive error of the IOL calculation was noted in one case, and an increase in IOP with the development of the posterior block in 1 case. These conditions required additional interventions and were stopped. Conclusion. Phacoemulsification with IOL in hypermetropia of a high degree improves the visual functions of this category of patients. It is necessary to take into account the short axial length of the eyeball when calculating the IOL and use several modern formulas. At the same time, the possibility of refractive error cannot be completely excluded, which should be discussed with the patient at the stage of planning the operation. Key words: phacoemulsification, hypermetropia, biometrics, IOL

Accuracy of Traditional and Modern Formulas for Intraocular Lens Power Calculation After Radial Keratotomy Using Standard Keratometry.

To compare the accuracy of multiple traditional and modern intraocular lens (IOL) power calculation formulas in post-radial keratotomy (RK) patients undergoing cataract surgery. This retrospective case series included 50 eyes with prior RK who underwent routine phacoemulsification surgery with single-piece acrylic IOL implantation (A constant = 118.8). Outcomes of multiple formulas were calculated. Included formulas were SRK/T, Holladay 1, Holladay 2, Haigis, Barrett True-K, Haigis and Barrett True-K (target refraction of 0.50 D), Barrett Universal II, Kane, PEARL-DGS, Shammas no history, DK SRK/T, DK SRK/T (target refraction of 0.50 D), Double K (DK) Holladay 1, and DK Holladay 1 (target refraction of 0.50 D). Averages of multiple combinations of best-performing single formulas were calculated. Primary outcome is mean absolute error (MAE). Haigis (with -0.50 D target refraction) and DK SRK/T showed the lowest mean and median absolute errors (MedAE) followed by Haigis, Barrett True-K, and Barrett True-K (with -0.50 D target refraction). Combinations of 3, 4, or 5 of best performing single formulas yielded good results with >60% of cases within +0.50 D of intended refraction and MAE around 0.50 D. The best performing formulas with flatter K readings were PEARL-DGS and Haigis (with additional -0.50 D target refraction) with MAE of 0.72 + 0.71 D and 0.70 + 0.70 D, respectively, followed by Barrett True-K (with intended -0.50 D target refraction) with MAE of 0.75 + 0.63 D. Using an average of three or more Haigis (with -0.50 D target refraction), the Barrett True-K, DK Holladay 1, and DK SRK/T formulas showed better outcomes than using a single formula for IOLMaster 700 standard K readings. The PEARL-DGS formula showed better accuracy in eyes with flatter K readings (<38 D).

Comparison of the prediction accuracy of 13 formulas in long eyes.

To investigate the accuracy of modern intraocular lens (IOL) power calculation formulas in eyes with axial length (AL) ≥ 26.00mm. A total of 193 eyes with one type of lens were analysed. An IOL Master 700 (Carl Zeiss Meditec, Jena, Germany) was used for optical biometry. Thirteen formulas and their modifications were evaluated: Barrett Universal II, Haigis, Hoffer QST, Holladay 1 MWK, Holladay 1 NLR, Holladay 2 NLR, Kane, Naeser 2, SRK/T, SRK/T MWK, T2, VRF and VRF-G. The User Group for Laser Interference Biometry lens constants were used for IOL power calculation. The mean prediction error (PE) and its standard deviation (SD), the median absolute error (MedAE), the mean absolute error (MAE) and the percentage of eyes with PEs within ± 0.25 D, ± 0.50 D and < ± 1.00 D were calculated. The modern formulas (Barrett Universal II, Hoffer QST, Kane, Naeser 2 and VRF-G) produced the smallest MedAE among all methods (0.30 D, 0.30 D, 0.30 D, 0.29 D and 0.28 D, respectively). The percentage of eyes with a PE within ± 0.50 D ranged from 67.48% to 74.85% for SRK/T and Hoffer QST, Naeser 2 and VRF-G, respectively. Dunn's post hoc test of the absolute errors revealed statistically significant differences (P < 0.05) between some of the newer formulas (Naeser 2 and VRF-G) and the remaining ones. From a clinical perspective the Hoffer QST, Naeser 2 and VRF-G formulas were more accurate predictors of postoperative refraction with the largest proportion of eyes within ± 0.50 D.

Analysis of intraocular lens displacement relative to the haptic plane by ultrasound biomicroscopy data

This study analyzed cases with postoperative displacement of intraocular lens (IOL) relative to the haptic plane using ultrasound biomicroscopy (UBM). The study analyzed biometry data of 231 patients (277 eyes) aged 72.39±7.77 years, among them 43.25% were males. IOL position and refraction were analyzed at 1, 3 and 6 months after standard phacoemulsification. UBM was performed to analyze the position of the IOL. Stabilization of lens position was observed by the 3rd month of observation. Among the cases with displacement of the optical part relative to the haptic plane, the forward shift was determined in 24.85%, backward - in 16.67% of cases. Eyes with opposite IOL displacements differed significantly in lens diameter, ciliary sulcus diameter and the power of implanted IOL. IOL shift towards the retina produced significant hyperopic refractive error. A discriminant function was compiled using preoperative biometry data comprising the model for predicting backward IOL displacement with high probability. However, we failed to obtain a qualitative model for forward IOL displacements. Calculation error in modern formulas could occur because of IOL displacement, including the shift of the optical part relative to the haptic plane in postoperative period. Analysis of biometry data allows calculating IOL displacement towards the retina with a high probability, which could help avoid hyperopic refraction error postoperatively.

Мембраны жировых глобул молока: значение для адаптации жирового компонента молочных смесей

Aim. Based on literature data, to analyze the clinical significance of the milk fat globule membrane in the nutrition of newborns and young children. Key points. Breast milk has been and remains the “gold standard” for feeding a child of the first year. The composition of modern formulas is based on the new information on the breast milk components, which have the most important programming impact on the growing child body. Currently, scientists pay special attention to the optimisation of the fat component of formulas with the introduction of milk fat globule membranes — a unique structure surrounding glycerine nucleus and comprising complex lipids in the form of phospholipids, gangliosides and cholesterol. Conclusion. The scientific studies demonstrated the critical role of “minor” lipids in the process of postnatal formation of the central nervous system and visual analyzer, the formation of the immune system and the regulation of metabolic processes. It is now reliably known that formulas with milk fat globule membranes are well-tolerated and have favourable effect on the prevention of infectious diseases and lipid exchange status. Keywords: milk formula, long chain polyunsaturated fatty acids, cell membranes, milk fat globule membrane

Breast milk oligosaccharides: what do we know today?

Breastfeeding remains the "gold standard" for feeding babies in the first year of life. Breast milk contains a mixture of nutrients; their amount varies throughout the lactation period and even throughout the day. The composition of breast milk (BM) is complex and dynamic. Currently, BM oligosaccharides (BMOs) are of most interest to researchers. Due to advances in science and biotechnology, more than 200 BMOs have been identified. Human BM is the richest source of oligosaccharides among all mammals (for instance, their content in cow's milk is almost 1,000 times lower). Numerous favorable effects of BMOs on child health are related to the immune response, gut barrier function, and protection against pathogens. BMOs as prebiotics contribute to the formation of the infant's intestinal microbiome. The BM contains a complex bacterial community whose composition depends on the maternal microbiome (skin, gut, genital, urethral tracts) that forms the infant gut microbial community. In the absence of breastfeeding, modern formulas can be used; BMOs in their composition make them more like BM.

Intraocular Lens Calculation Using 8 Formulas in Silicone Oil–Filled Eyes Undergoing Silicone Oil Removal and Phacoemulsification After Retinal Detachment

To evaluate formulas for intraocular lens (IOL) calculation in silicone oil (SO)-filled eyes. Retrospective, consecutive case series. We conducted our study at the Department of Ophthalmology, Goethe University, Frankfurt, Germany, and included SO-filled eyes that received SO removal combined with phacoemulsification and IOL implantation. Preoperative assessments included biometry (IOLMaster 700; Carl Zeiss Meditec). To evaluate the measurements, we compared the mean prediction error, and mean and median absolute prediction error of 8 different formulas. A total of 90 eyes matched our inclusion criteria. The median absolute error was lowest in the Barrett Universal II formula (0.43 diopters [D] ± 0.75) followed by Kane (0.44 D ± 0.75), Hill-radial basis function (0.47 D ± 0.74), Holladay II (0.47 D ± 0.77), Sanders Retzlaff Kraff/theoretical (0.51 D ± 0.74), Holladay I (0.51 D ± 0.76), and Haigis and Hoffer Q (0.52 D ± 0.74 each). Regarding eyes within ±0.5 D Barrett Universal II (57.8%, 52 eyes) performed best, again followed by Kane (56.7%, 51 eyes) and Hill-radial basis function (54.4%, 49 eyes). Using modern formulas for IOL calculation in oil-filled eyes improves predictability but still not as good as in unoperated eyes. This issue is created by the change in refractive index due to the SO fill and therefore a lower precision of axial length measurement and effective lens position prediction.

Errors in IOL Power Calculation in Rare Clinical Cases. Literature Review

The postoperative result is determined not only by technique of a surgeon, the availability of modern innovative equipment, but also due to the accurate diagnostics and skilled interpretation of biometric, keratometric parameters; the use of modern formulas of IV, V generations to calculate the optical power of the intraocular lens (IOL), allowing to predict the correct position of the IOL, through the use of predictive variables that determine the postoperative lens position. The variety of modern research methods and continuous improvement of formulas for lens calculation allows us to get the closest results to emmetropia.

Alternative method of intraocular lens power calculation in eyes with short axial length

To develop an alternative method of intraocular lens (IOL) power calculation in eyes with mature cataract and axial length (AL) of less than 22.0 mm using modern formulas Barrett Universal II and Hill RBF. The study enrolled 41 patients (41 eyes) who underwent phacoemulsification (PE). Ultrasound biometry (Tomey Biometer Al-100) and keratometry (Topcon-8800) were used for IOL power calculation by SRK/T and Haigis formulas. To calculate IOL power by Barrett Universal II and Hill RBF formulas, 0.2 mm were added to AL measured with ultrasonography (retinal thickness). One month after PE, spherical equivalent of refraction was compared with target refraction (calculated by the formulas listed above), and based on that a conclusion was made on the accuracy of calculations. Haigis formula was found to be the least accurate (IOL calculation error -0.39±0.79 D). The calculation error in SRK/T (0.04±0.79 D), Barrett Universal II (0.02±0.79 D) and Hill RBF (-0.05±0.73 D) formulas was much lower. However, among them Hill RBF had the lowest spread of the mean absolute IOL calculation error. Pairwise comparison revealed significant difference of mean IOL calculation error by Haigis formula versus the others. There was no significant difference in the following pairs: SRK/T - Barrett Universal II (p=0.855), and SRK/T - Hill RBF (p=0.167), but there was a significant difference (p=0.043) in the Barrett Universal II - Hill RBF pairdue to the tendency for slight hypermetropic calculation error in the former and the inherent slight myopic shift in the latter.. The proposed alternative method of IOL power calculation in eyes with mature cataract and short AL using modern formulas (Barrett Universal II and Hill RBF) shows higher accuracy compared to the formulas embedded in ultrasound biometer (SRK/T and Haigis), and can be recommended for use in everyday practice.

Toric Intraocular Lenses for the Management of Corneal Astigmatism at the Time of Cataract Surgery

Methods This audit was conducted in a UK ophthalmology department and included 48 eyes of 42 patients. Surgery was performed during 2019 in patients with 2.50 diopters (D) or more corneal astigmatism. Anterior keratometry readings were used to determine the toric IOL power. Vector analysis using the Alpins method was used to assess changes in astigmatism pre to postoperatively. Results There were 18 right and 26 left eyes included. In terms of gender, 61% of patients were female and 39% were male. The mean (±standard deviation (SD)) age was 70 (±11) years. The mean (±SD) axial length, K1, K2, and delta K was 23.55 (±1.4) mm, 42.71 (±1.39) D, 45.78 (±1.60) D, and 3.01 (±0.89) D, respectively. Postoperatively, the median spherical, cylinder, and spherical equivalent refraction was 0.00 D, −1.00 D, and 0.00 D, respectively. Postoperatively, 41% of the eyes had ≤0.50 D of spectacle astigmatism and 80% had ≤1.00 D. No patient required a secondary procedure to reposition the IOL from rotation. In vector analysis with the use of polar diagrams, there was a tendency for overcorrection of with-the-rule astigmatism and undercorrection of against-the-rule astigmatism. Conclusions Significant reductions in astigmatism can be achieved with the use of toric IOLs in patients undergoing cataract surgery. Further improvements may be possible with surgeon-specific determination of their surgically induced astigmatism and flattening effect from the main corneal incision. Furthermore, the use of an optical biometer that directly measures the posterior corneal curvature and permits automatic toric IOL power determination with modern formulas avoiding the need for manual data entry may reduce the risk of human error and improve visual and refractive outcomes.