Intraocular lens power calculation with an improved anterior chamber depth prediction algorithm

Olsen, Thomas; Corydon, Leif; Gimbel, Howard V.

doi:10.1016/s0886-3350(13)80140-x

Cited by 166 publications

(100 citation statements)

References 18 publications

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“…(2,(10)(11)(12) In other words, the impact of the major contributors to refractive error following cataract surgery has been substantially reduced by improvements in measures of biometric parameters 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Optimized versus Personalized Lens Constants 6 Further, personalization of lens constants to the individual surgeon has been advocated by many authors for almost 30 years and it is believed to represent an important step if yet further improvements in refractive outcomes following cataract surgery are to be realized. (2,(13)(14)(15)(16)(17) The IOL power prediction curve of the 3 rd generation 2-variable formulas is mostly fixed and is moved up or down depending on the IOL constant (the larger the IOL constant, the more IOL power each formula will recommend for the same set of biometric measurements; and the smaller the IOL constant, the less IOL power the same formula will recommend for the same set of biometric measurements). Those formulas do not take into account the individual geometry of each lens model.…”

Section: Refractive Resultsmentioning

confidence: 99%

Effect on refractive outcomes after cataract surgery of intraocular lens constant personalization using the Haigis formula

Charalampidou¹,

Cassidy²,

Ng³

et al. 2010

Journal of Cataract and Refractive Surgery

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Methods: A postal survey of all consultant ophthalmic surgeons in the UK and Ireland, regarding the practice of lens constant personalization, was carried out. Also, mean error (ME) of prediction and mean absolute error (MAE) were calculated for a single-surgeon (SB) series of eyes after biometry by partial coherence interferometry (PCI) with the IOL Master and phacoemulsification cataract surgery, where the IOL prediction was based on the Haigis formula and optimized lens constants derived from pooled data from the ULIB (User Group for Laser Interference Biometry) website. Personalization of Haigis lens constants to the same operating surgeon was then performed. An ME of prediction and an MAE using the personalized lens constants was then calculated for the same series of eyes which had been operated upon using the Haigis optimized (but not personalized) lens constants, thereby allowing us to investigate and quantify the maximum realizable refractive benefits (if any) of personalization. 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 Optimized versus Personalized Lens Constants 3 Results: Survey:The survey response rate was 56 %. One hundred and ten (21.7%) of the 506 consultant ophthalmic surgeons in the UK and Ireland who answered the questionnaire did formally personalize their lens constants by a recognized and validated method. The most common reason for non-personalization of lens constants was the use of optimized lens constants derived from pooled data. Refractive results:The ME of prediction and the MAE with Haigis optimized lens constants were -0.09 D (

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Section: Refractive Resultsmentioning

confidence: 99%

Effect on refractive outcomes after cataract surgery of intraocular lens constant personalization using the Haigis formula

Charalampidou¹,

Cassidy²,

Ng³

et al. 2010

Journal of Cataract and Refractive Surgery

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“…Katarakt cerrahisi planlanmasında biyometrinin yeri vazgeçil-mezdir. ÖKD ölçümündeki hata GİL diyoptrisinin yanlış ölçülmesine sebep olabilmektedir [16]. Son yıllarda geliştirilen biyometri formülleriyle cerrahi sonrası GİL pozisyonu tahmini yapılabilmektedir.…”

Section: Discussionunclassified

Comparison of anterior segment parameters with pentacam according to age in emmetropic eyes

Çınar¹,

Cingü²,

Çınar³

et al. 2013

DicleMedj

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Objective: It was aimed to compare anterior segment parameters obtained by rotating Scheimpflug camera system according to age groups.Methods: 290 eyes of 145 emmetropic subjects were included in the study. Subjects were divided in three age groups. Group 1 comprised the subjects age up to 20 years, Group 2 comprised the subjects age between 21 and 40 and Group 3 comprised the subjects between 41 years and older. In all subjects, flat keratometry (K1), steep keratometry (K2), mean corneal power (Km), maximum keratometry (Kmax), central corneal thickness (CCT), apex corneal thickness (ACT), thinnest corneal thickness (TCT), anterior chamber volume (ACV) and anterior chamber depth (ACD) were obtained by using rotating Scheimpflug camera system. To eliminate operator dependent variables, automatic release mode was used. All measurements were obtained by the same examiner. Results:The study included 72 female and 73 male subjects. The mean age of the subjects was 31.37±12.29 years (range, 8-65). There were no significant differences in keratometric values between age groups. There was significant difference between Groups 1 and 3 and Groups 2 and 3 in the mean CCT, ACT and TCT (p<0.05). There was significant difference between the groups in the mean ACD and ACV. There significant positive correlation between age and CCT (r=0.181, p=0.001), ACT (r=0.161, p=0.006) and TCT (r=0.16, p=0.006). There were significant negative correlations between age and ACD (r=-0.376, p<0.001) and ACV (r=-0.367, p<0.001). Conclusion:In the emmetropic eyes, significant reduction was found in ACD and ACV, while there was significant increase in CCT, ACT and TCT by age. Yöntemler: Çalışmaya katılan 145 emetrop olgunun 290 gözüne ait Pentacam parametreleri değerlendirildi. Olgular yaşlarına göre üç gruba ayrıldı. Grup 1, yirmi yaşına kadar olan olguları, grup 2, 21-40 yaş arası olan olguları ve grup 3, ise 41 yaşından büyük olan olguları içermek-teydi. Tüm olguların düz keratometri (K1), dik keratometri (K2), ortalama kornea kırıcılığı (Km), maksimum keratometri (Kmax), merkezi kornea kalınlığı (MKK), apeks kornea kalınlığı (AKK), en ince kornea kalınlığı (EİKK), ön kamara hacmi (ÖKH) ve ön kamara derinliği (ÖKD) değerlendirmeye alındı. Ölçümler sırasında kullanıcıya bağlı değişkenleri ekarte etmek amacıyla otomatik çekim modu kullanıldı ve tüm çekimler aynı araştırmacı tarafın-dan yapıldı. Bulgular:Olguların 72'si kadın, 73'ü ise erkekti ve ortalama yaşları 31,37±12,29 yıl (8-65 yıl) idi. Keratometrik değerler açısından yaş grupları arasında anlamlı farklı-lık saptanmadı. Ortalama MKK, AKK ve EİKK değerleri açısından grup 1-3 ve grup 2-3 arasında, ortalama ÖKH ve ÖKD değerleri arasından ise tüm gruplarda istatistiksel olarak anlamlı farklılık mevcuttu (p<0,05). Yaş ile MKK (r=0,181, p=0,001), AKK (r=0,161, p=0,006) ve EİKK (r= 0,16, p=0,006) arasında anlamlı pozitif korelasyon saptanırken, yaş ile ÖKD (r=-0,376, p<0,001) ve ÖKH arasında (r=-0,367, p<0,001) anlamlı negatif korelasyon saptandı.Sonuç: Emetropik olgularda ileri yaş grup...

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“…The goal is to secure an optimal visual acuity (VA) у6/12, which can only be achieved with exact lens power calculation and control of the surgically induced astigmatism. New formulae for intraocular lens power calculation have improved the accuracy (Olsen et al 1995). Variation of astigmatism with age has been recognised for years.…”

Section: Discussionmentioning

confidence: 99%

Possible factors modifying the surgically induced astigmatism in cataract surgery

Storr‐Paulsen

Madsen

Perriard

1999

Acta Ophthalmologica Scandinavica

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ABSTRACT.Purpose: To investigate possible modifiers of the surgically induced astigmatism with special reference to age, gender, preoperative astigmatism, and the intraocular pressure. Methods & patients: Data for one hundred and one cataract patients operated on with extracapsular cataract extraction and intraocular lens implantation were prospectively recorded and followed for six years. Different explanatory variables like age, gender, preoperative astigmatism and postoperative intraocular pressure (IOP) were considered. Astigmatic changes were calculated as Naeserøs polar values. Results: The surgically induced astigmatism was not significant at one year, but was significantly increased 3-and 6-years postoperatively. At the same time the keratometric axis made a shift toward against-the-rule astigmatism. The postoperative mean-IOP was lower at all controls. Multiple regression analysis showed that a large preoperative astigmatism, a low postoperative IOP, and high age resulted in more surgically induced astigmatism against-the-rule. Conclusion: The length and the architecture of the incision are known to have an influence on the surgically induced astigmatism in cataract surgery. In the present study we used a multiple regression analysis model to show a significant correlation between the surgically induced astigmatism and age, preoperative astigmatism, and postoperative IOP.Key words: cataract surgery -surgically induced astigmatism -modifying factors -age -preoperative astigmatism -postoperative IOP.

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Intraocular lens power calculation with an improved anterior chamber depth prediction algorithm

Cited by 166 publications

References 18 publications

Effect on refractive outcomes after cataract surgery of intraocular lens constant personalization using the Haigis formula

Effect on refractive outcomes after cataract surgery of intraocular lens constant personalization using the Haigis formula

Comparison of anterior segment parameters with pentacam according to age in emmetropic eyes

Possible factors modifying the surgically induced astigmatism in cataract surgery

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