Intraocular lenses optic power calculation with seven formulas in short eyes

Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods.A total of 78 patients (118 eyes) were included in theprospective study. Group I included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60 ± 0.42 (18.54-20.0) mm), group II consisted of 48 patients (66 eyes) with a axial length (22.75 ± 0.46 (22.0-23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison - according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.85; 0.78; 0.21; 0.17; 0.79; 0.73; 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK / T and Holladay II (p <0.05) in all cases, respectively. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.15; 0.16; 0.23; 0.10; 0.19; 0.23; 0.29 respectively) In group II, there were no significant differences between the studied formulas (p> 0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay 2, Olsen, and SRK / T is shown. Key words: cataract; hypermetropia; short eyes; calculation of the IOL optical power.

Intraocular lenses optic power calculation with seven formulas in short eyes

Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods. A total of 78 patients (118 eyes) were included in the prospective study. 1st group included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60±0.42 (18.54–20.0) mm), 2nd group consisted of 48 patients (66 eyes) with a axial length 22.75±0.46 (22.0–23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison – according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In 1st group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.85, 0.78, 0.21, 0.17, 0.79, 0.73, 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK/T and Holladay II (p<0.05) in all cases, respectively. In 2nd group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.15, 0.16, 0.23, 0.10, 0.19, 0.23, 0,29 respectively). In 2nd group, there were no significant differences between the studied formulas (p>0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay II, Olsen, and SRK/T is shown. Key words: cataract, hypermetropia, short eyes, calculation of the IOL optical power.

Accuracy of partial coherence interferometry in patients with large inter-eye axial length difference

Background To determine accuracy of partial coherence interferometry (PCI) in patients with large inter-eye axial eye length (AEL) difference. Methods Patients undergoing cataract surgery at two academic medical centers with an inter-eye axial eye length (AEL) difference of > 0.30 mm were identified and were matched to control patients without inter-eye AEL difference > 0.30 mm on the basis of age, sex, and AEL. The expected post-operative refraction for the implanted IOL was calculated using SRK/T, Holladay II, and Hoffer Q formulae. The main outcome measures were the refractive prediction error and the equivalence of the refractive outcomes between the subjects and controls. Results Review of 2212 eyes from 1617 patients found 131 eyes of 93 patients which met inclusion criteria. These were matched to 131 control eyes of 115 patients. The mean AEL was 24.92 ± 1.50 mm. The mean absolute error (MAE) ranged from 0.47 D to 0.69 D, and was not statistically different between subjects and controls. The refractive prediction error was equivalent between the cases and controls, with no significant difference between the MAE for any formula, nor in the number of cases vs. controls with a refractive prediction error of at least 0.50 D or 1.00 D. Conclusions Among eyes in our study population, good-quality PCI data was equally accurate in patients with or without an inter-eye AEL difference > 0.30 mm. Confirmatory AEL measurements using different AEL measuring modalities in patients with a large inter-eye AEL difference may not be necessary.

Project hyperopic power prediction: accuracy of 13 different concepts for intraocular lens calculation in short eyes

PurposeTo evaluate the accuracy of intraocular lens (IOL) power calculation in a patient cohort with short axial eye length to assess the performance of IOL power calculation schemes in strong hyperopes.MethodologyThe study was a single centre, single surgeon retrospective consecutive case series at the Augen- und Laserklinik, Castrop-Rauxel, Germany. Inclusion of patients after uneventful cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were axial eye length <21.5 mm and/or emmetropising IOL power >28.5 D. Lens constants were optimised on a separate patient cohort considering the full bandwidth of axial eye length. Data of one single eye per patient were randomly included. The outcome measures were: mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with SD and median prediction error and the percentage of eyes with an MAE within 0.25 D, 0.5 D, 0.75 D and 1.0 D.ResultsA total of 150 eyes from 150 patients were assessed. Okulix, PEARL-DGS, Kane and Castrop provided a statistically significantly smaller MAE compared with the Hoffer Q and SRK/T formulae.ConclusionIn our patient cohort with short axial eye length, the use of PEARL-DGS, Okulix, Kane or Castrop formulae showed the lowest MAE. The Castrop formula has not been published before, but will be disclosed with a ready-to-use Excel sheet as an addendum to this paper.

Features of the dynamics of axial eye length and refraction in case ofpseudophakia in children with a risk of myopia

Актуальность. Контроль отдаленных рефракционных результатов у детей после экстракции врожденной катаракты (ВК) с имплантацией ИОЛ, их коррекция, профилактика незапланированной аметропии при риске аномального рефрактогенеза остаются одной из самых значимых проблем в детской офтальмологии. Цель. Оценка роста передне-задней оси (ПЗО)глазного яблока и динамики рефракции у детей с риском миопии после экстракции ВК с имплантацией ИОЛ. Материал и методы. Под нашим наблюдением находились 26 (42 глаза) детей с ВК. По возрасту пациенты были разделены на 3 группы: I группа от1 до 3 лет, II – от 3 до 5 лет и III – старше 5 лет. Анализ ПЗО и рефракции проводили через 36 месяцев после имплантации ИОЛ. Детей с риском миопии было 10 (15глаз), без – 16 (27глаз). Пациентам проводилась экстракапсулярная экстракция ВК с имплантацией сферо-сферичных моноблочных ИОЛ(Acrysof iQ, Acrysof Natural). Расчет силы ИОЛ проводился по формуле SRK II c возрастной гипокоррекцией по Trivedi R.H. Результаты. ПЗО глаза в I группе увеличилась с момента имплантации в среднем на 1.3 мм, во II –на 0.98 мм, в III - на 0.68 мм, и это увеличение превосходило возрастную динамику. Рост ПЗО на 1ммсопровождался усилением рефракции в I группе на0,82±0,03 дптр, во II – на 0,71±0,02 дптр и III – на0,57±0,01 дптр. Рефракция при артифакии отличалась от запланированной во всех трех группах. Выводы. У детей с предрасположенностью к миопии после имплантации ИОЛ выявлена остаточная рефракция и рост ПЗО, превосходящие возрастную норму.

Accuracy of common IOL power formulas in 611 eyes based on axial length and corneal power ranges

AimsTo provide clinical guidance on the use of intraocular lens (IOL) power calculation formulas according to the biometric parameters.Methods611 eyes that underwent cataract surgery were retrospectively analysed in subgroups according to the axial length (AL) and corneal power (K). The predicted residual refractive error was calculated and compared to evaluate the accuracy of the following formulas: Haigis, Hoffer Q, Holladay 1 and SRK/T. Furthermore, the percentages of eyes with ≤±0.25, ≤±0.5 and 1 dioptres (D) of the prediction error were recorded.ResultsThe Haigis formula showed the highest percentage of cases with ≤0.5 D in eyes with a short AL and steep K (90%), average AL and steep cornea (73.2%) but also in long eyes with a flat and average K (65% and 72.7%, respectively). The Hoffer Q formula delivered the lowest median absolute error (MedAE) in short eyes with an average K (0.30 D) and Holladay 1 in short eyes with a steep K (Holladay 1 0.24 D). SRK/T presented the highest percentage of cases with ≤0.5 D in average long eyes with a flat and average K (80.5% and 68.1%, respectively) and the lowest MedAE in long eyes with an average K (0.29 D).ConclusionOverall, the Haigis formula shows accurate results in most subgroups. However, attention must be paid to the axial eye length as well as the corneal power when choosing the appropriate formula to calculate an IOL power, especially in eyes with an unusual biometry.

Intraocular Pressure Measurements in Standing Position with a Rebound Tonometer

Background and Objectives: It has been established that body position can play an important role in intraocular pressure (IOP) fluctuation. IOP has been previously shown to increase significantly when lying down, relative to sitting; this type of investigation has not been extensively reported for the standing (ST) position. Therefore, this study aims to look for eventual significant IOP changes while ST, sitting, and lying down. Materials and Methods: An Icare PRO was used to measure the IOP of 120 eyes of 60 healthy individuals, with age ranging from 21 to 55 years (mean 29.22 ± 9.12 years), in sitting, supine and ST positions; IOP was measured again, 5 minutes after standing (ST-5m). Results: Mean IOP difference between sitting and ST position was 0.39 ± 1.93 mmHg (95% CI: 0.04 to 0.74 mmHg) (p = 0.027); between sitting and ST-5m, it was −0.48 ± 1.79 mmHg (95% CI: −0.8 to −0.16 mmHg) (p = 0.004); between the sitting and supine position, it was −1.16±1.9 mmHg (95% CI: −1.5 to −0.82 mmHg) (p < 0.001); between the supine and ST position, it was 1.55 ± 2.04 mmHg (95% CI: 1.18 to 1.92 mmHg) (p < 0.001); between supine and ST-5m, it was 0.68 ± 1.87 mmHg (95% CI: 0.34 to 1.02 mmHg) (p < 0.001); and between ST-5m and ST, it was 0.94 ± 1.95 mmHg (95% CI: 0.58 to 1.29 mmHg) (p < 0.001). Mean axial eye length was 24.45 mm (95% CI: 24.22 to 24.69 mm), and mean central corneal thickness was 535.30 μm (95% CI: 529.44 to 541.19 μm). Conclusion: Increased IOP in the ST-5m position suggests that IOP measurements should be performed in this position too. The detection of higher IOP values in the ST-5m position than in the sitting one, may explain the presence of glaucoma damage or progression in apparently normal-tension or compensated patients.