1
|
Sella R, Reitblat O, Durnford KM, Pettey JH, Olson RJ, Hahn TE, Bernhisel AA, Afshari NA. The effect of patient age on some new and older IOL power calculation formulas. Acta Ophthalmol 2024; 102:e696-e704. [PMID: 38155407 DOI: 10.1111/aos.16621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 12/30/2023]
Abstract
PURPOSE To assess the accuracy of intraocular lens (IOL) power calculation in different age groups using various IOL calculation formulas. METHODS Data from 421 eyes of 421 patients ≥60 years old (ages: 60-69, n = 131; 70-74, n = 105; 75-84, n = 158 and ≥85, n = 27), who underwent uneventful cataract surgery with SN60WF IOL implantation at John A. Moran Eye Center, Salt Lake City, USA, were retrospectively obtained. The SD of the prediction error (PE), median and mean absolute PEs and the percentage of eyes within ±0.25, ±0.50, ±0.75 and ±1.00 D were calculated after constant optimizations for the following formulas: Barrett Universal II (BUII), Emmetropia Verifying Optical (EVO) 2.0, Haigis, Hoffer Q, Hoffer QST, Holladay 1, Kane, Radial Basis Function (RBF) 3.0 and SRK/T. Results were compared between the different age groups. RESULTS Predictability rates within 0.25D were lower for the eldest age group compared with the other groups using the EVO 2.0 (33% vs. 37%-53%, p = 0.045), Kane (26% vs. 35%-50%, p = 0.034) and SRK/T (22% vs. 31%-49%, p = 0.002). Higher median absolute refractive errors for all formulas were observed in the oldest group [range: 0.39 D (Haigis, Hoffer QSR)-0.48 D (Kane)], followed by the youngest group [range: 0.30 D (RBF 3.0)-0.39 D (Holladay 1, SRK/T)] but did not reach statistical significance. No significant differences between the groups in the distribution parameter were seen. CONCLUSION Current IOL power calculation formulas may have variable accuracy for different age groups. This should be taken into account when planning cataract surgery to improve refractive outcomes.
Collapse
Affiliation(s)
- Ruti Sella
- Department of Ophthalmology, Rabin Medical Center, Petah Tikva, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
- Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, California, USA
| | - Olga Reitblat
- Department of Ophthalmology, Rabin Medical Center, Petah Tikva, Israel
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | | | - Jeff H Pettey
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Randall J Olson
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Tara E Hahn
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Ashlie A Bernhisel
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA
- Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, California, USA
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA
| | - Natalie A Afshari
- Viterbi Family Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, California, USA
| |
Collapse
|
2
|
Yokogawa T, Mori Y, Torii H, Goto S, Hasegawa Y, Kojima T, Kamiya K, Shiba T, Miyata K. Accuracy of intraocular lens power formulas in eyes with keratoconus: Multi-center study in Japan. Graefes Arch Clin Exp Ophthalmol 2024; 262:1839-1845. [PMID: 38217766 DOI: 10.1007/s00417-024-06371-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 12/30/2023] [Accepted: 01/04/2024] [Indexed: 01/15/2024] Open
Abstract
PURPOSE To assess the accuracy of intraocular lens (IOL) power formulas, namely, SRK/T, Haigis, Barrett Universal II, Barrett True-K for keratoconus, Kane formula, and Kane formula for keratoconus, for cataract with keratoconus in Japanese eyes. SETTING Five surgical sites in Japan. DESIGN A retrospective case series. METHODS Eyes with keratoconus undergoing cataract surgery were included. Postoperative refraction was compared with the prediction by the formulas. Visual acuity, manifest spherical equivalent, prediction error (PE), and mean absolute errors (MAEs) were determined 1 month postoperatively. The PE within 0.50 diopter (D), 1.00 D, and 2.00 D were compared between IOL formulas. Subgroup analysis based on the steepest keratometry (stage 1, ≤ 48 D; stage 2, > 48 D and ≤ 53 D; and stage 3, > 53 D) was performed. The relationship between PE and preoperative biometric data were assessed. RESULTS Fifty eyes were included. The MAE of the Barrett True-K for keratoconus, Kane keratoconus, and Kane formulas were significantly lower than that of Haigis. A statistically significant difference in the prediction accuracy within ± 0.50 D was found between Kane keratoconus and Haigis. The prediction accuracy of the Barrett True-K for keratoconus, SRK/T, and Kane within ± 1.00 D was statistically significant compared with that of Haigis. In stage 3, the Barrett True-K for keratoconus had a significantly lower MAE than SRK/T and Haigis. CONCLUSION Keratoconus-specific formulas were more accurate than existing formulas in Japanese eyes. The Barrett True-K formula for keratoconus had higher prediction accuracy in severe keratoconus.
Collapse
Affiliation(s)
- Tomohiro Yokogawa
- Miyata Eye Hospital, Kurahara 6-3, Miyakonojo, Miyazaki, 885-0051, Japan.
| | - Yosai Mori
- Miyata Eye Hospital, Kurahara 6-3, Miyakonojo, Miyazaki, 885-0051, Japan
| | - Hidemasa Torii
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-Ku, Tokyo, 160-8582, Japan
| | - So Goto
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Room E7, Yamadaoka 2-2, Suita, Osaka, 565-0871, Japan
- Department of Ophthalmology, Tokyo Medical Center, National Hospital Organization, 2-5-1 Higashigaoka, Meguro-Ku, Tokyo, 152-8902, Japan
- Herbert Wertheim School Optometry and Vision Science, University of California, Berkeley, CA, 94720-2020, USA
| | - Yumi Hasegawa
- Department of Ophthalmology, Faculty of Medicine, University of Tsukuba, 2-1-1 Amakubo, Tsukuba, Ibaraki, 305-8076, Japan
| | - Takashi Kojima
- Nagoya Eye Clinic, 24-14 Namiyose, Atsuta-Ku, Nagoya, Aichi, 456-0003, Japan
| | - Kazutaka Kamiya
- Department of Ophthalmology, Kitasato University, 1-15-1 Kitasato, Minami-Ku, Sagamihara, Kanagawa, 252-0373, Japan
| | - Takuya Shiba
- Roppongi Shiba Eye Clinic, Minato-Ku, Tokyo, Japan
| | - Kazunori Miyata
- Miyata Eye Hospital, Kurahara 6-3, Miyakonojo, Miyazaki, 885-0051, Japan
| |
Collapse
|
3
|
Coutinho CP, Schiano-Lomoriello D, Mazzotta C, Ferrise M, Hoffer KJ, Ribeiro FJ, Dias JM, Savini G. Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results. J Refract Surg 2024; 40:e253-e259. [PMID: 38593262 DOI: 10.3928/1081597x-20240311-06] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
PURPOSE To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. METHODS In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters. In a separate sample of keratoconic eyes that had undergone cataract surgery, IOL power was calculated with the Barrett Universal II, Hoffer QST, Holladay 1, Kane, and SRK/T formulas using the SimK and an adjusted TCP power. The respective prediction errors were calculated. RESULTS A total of 382 keratoconic eyes (271 patients) were enrolled. An increasing overestimation of SimK by TCP was detected from stage I to III, with a significant correlation between the SimK and TCP difference and SimK in the whole sample (P < .0001, r2 = 0.1322). Approximately 7% of cases presented an underestimation of SimK by TCP. IOL power calculation with the adjusted TCP improved outcomes, achieving a maximum of 80% of eyes with a prediction error within ±0.50 diopters with the Hoffer QST, Holladay 1, and Kane formulas. CONCLUSIONS Overall, SimK overestimated TCP. Such a difference could not be predicted by any variable. The proposed TCP-adjustment formula (TCPadj = TCP + 0.56 diopters) in keratoconic eyes for IOL power calculation might be valuable for improving refractive outcomes. [J Refract Surg. 2024;40(4):e253-e259.].
Collapse
|
4
|
Camellin U, Ninotta I, Latino G, Alibrandi A, Aragona P, Roszkowska AM. Prediction of total corneal power in keratoconus using anterior surface data. Clin Exp Optom 2024; 107:274-280. [PMID: 37271161 DOI: 10.1080/08164622.2023.2215382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 05/09/2023] [Accepted: 05/12/2023] [Indexed: 06/06/2023] Open
Abstract
CLINICAL RELEVANCE Keratoconus results in an increase in anterior and posterior curvatures and a reduction in corneal thickness. Anterior corneal ectasia is partially compensated by remodelling the corneal epithelium. Therefore, there is an alteration in the relationship between corneal surfaces and variation in corneal power. The variation in corneal power is one of the sources that induces errors in IOL power calculation. BACKGROUND This study aimed to assess a method for predicting total corneal power in keratoconus using several anterior surface parameters at 3 mm and 4 mm. METHODS Tomographic data obtained using Pentacam (Oculus, Germany) were analysed from 280 eyes of 140 patients with keratoconus using anterior and posterior keratometry, anterior Q-value at 8 mm, central corneal thickness, Kmax location and value, and true net power at 4 mm (TNP). Calculated total corneal power (TCPc) at 3 mm was obtained using the Gauss formula. Predicted total corneal power at 3 mm (TCPp3) and 4 mm (TCPp4) was obtained from univariate (TCPp3u and TCPp4u) and multivariate linear regression formulae (TCPp3m and TCPp4m). SimK, anterior Q-value, vertical location, and Kmax value were used in the multivariate formulae. Mean absolute error (MAE) and median absolute error (MedAE) were also calculated. Absolute frequencies within dioptric ranges of all formulas divided for keratoconus grading were evaluated. RESULTS TCPc and TNP exhibited a good correlation (R2 = 0.58, p < 0.05) with a higher dispersion above 50 D of corneal power. Highly significant correlations were observed between TCPp3u and TCPc (R2 = 0.978, p < 0.05) and TCPp3m and TCPc (R2 = 0.989, p < 0.05). Lower but significant correlations were observed between TCPp4u and TNP (R2 = 0.692, p < 0.05) and between TCPp4m and TNP (R2 = 0.887, p < 0.05). The best results for TCP prediction at 3 and 4 mm were obtained with TCPp3m and TCPp4m as follows: MAE of TCPp3m was 0.24 ± 0.20 (SD) D with MedAE of 0.20 D, while MAE of TCPp4m was 0.96 ± 0.77 D with MedAE of 0.80 D. The 3 mm multivariate regression formula results in higher absolute frequencies of prediction errors in the total eyes within 0.5 D (93%) than the univariate formula (81%). At 4mm, the multivariate regression formula has a lower percentage within 0.5 D (32%) than the univariate formula (41%), but the percentage of the multivariate formula is higher within 1 D (63%) than the univariate formula (56%). CONCLUSION All formulas show a decrease in accuracy with increasing grades of keratoconus. Multivariate linear regression formulae using only anterior surface data can predict TCP with good approximation in eyes with keratoconus in cases where posterior surface parameters are unavailable. The vertical location of Kmax and the anterior asphericity could play a relevant role in the prediction of total corneal power in keratoconus.
Collapse
Affiliation(s)
- Umberto Camellin
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Ivan Ninotta
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Gianluigi Latino
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | | | - Pasquale Aragona
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
| | - Anna M Roszkowska
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy
- Department of Ophthalmology, Andrzej Frycz Modrzewski Krakow University, Kraków, Poland
| |
Collapse
|
5
|
Nanavaty MA, Ashena Z, Bekono-Nessah I, Harding J. Development of a Web-Based Algorithm for Understanding the Intraocular Lens-Based Surgery in Stable and Progressing Keratoconus for Non-Specialist Ophthalmologists. Curr Eye Res 2024; 49:140-149. [PMID: 37870048 DOI: 10.1080/02713683.2023.2270727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 10/10/2023] [Indexed: 10/24/2023]
Abstract
PURPOSE To propose an algorithm to facilitate lens-based surgery in keratoconus. METHODS A literature review was performed to prepare a software algorithm based on cone location, stability, best spectacle-corrected distance visual acuity (BSCVA) level and whether there is a clear or cataractous lens. The software usability was assessed through a 10-question questionnaire and two hypothetical keratoconus case histories (moderately simple and moderately complex) given to 15 trainees. The usability questionnaires were graded on a Likert scale (1 = strongly disagree to 5 = strongly agree) and two case histories (1 = very difficult to 7 = very easy). RESULTS The algorithm can be found at https://www.sussexeyelaserclinic.co.uk/keratoconus/. Thirteen trainees completed the questionnaire. 91.9% would frequently use it; for 100%, it was easy to use independently without technical support; for 63.7%, it was strongly integrated; for 100%, it was consistent; 100% thought that most people would learn to use it quickly, 91.9% found the system not cumbersome to use, felt very confident to use it and need not learn a lot to use it. The first case was found easy by 63.7% and the second by 45%. CONCLUSION We present an algorithm as a guide for lens-based surgery in stable and progressing keratoconus, which is classified based on cone location. This algorithm will help trainee and "non-specialist" ophthalmic surgeons understand the pre-operative planning for the surgery and referral to the "specialist" corneal surgeon, considering factors such as progression, BSCVA, keratometry, topography and apex location of the cone in keratoconus patients.
Collapse
Affiliation(s)
- Mayank A Nanavaty
- Sussex Eye Hospital, Brighton & Sussex University Hospitals NHS Trust, Brighton, United Kingdom
- Brighton & Sussex Medical School, University of Sussex, Falmer, Brighton, United Kingdom
| | - Zahra Ashena
- Sussex Eye Hospital, Brighton & Sussex University Hospitals NHS Trust, Brighton, United Kingdom
| | - Ingrid Bekono-Nessah
- Brighton & Sussex Medical School, University of Sussex, Falmer, Brighton, United Kingdom
| | - Jennie Harding
- Department of Business Computing, University of Brighton, Brighton, United Kingdom
| |
Collapse
|
6
|
Heath MT, Mulpuri L, Kimiagarov E, Patel RP, Murphy DA, Levine H, Tonk RS, Cooke DL, Riaz KM. Intraocular Lens Power Calculations in Keratoconus Eyes Comparing Keratometry, Total Keratometry, and Newer Formulae. Am J Ophthalmol 2023; 253:206-214. [PMID: 37044197 DOI: 10.1016/j.ajo.2023.03.037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 03/19/2023] [Accepted: 03/21/2023] [Indexed: 04/14/2023]
Abstract
PURPOSE To compare the utility of keratometry vs total keratometry (TK) for intraocular lens power calculations in eyes with keratoconus (KCN) using KCN and non-KCN formulae. DESIGN Retrospective cohort study. METHODS This study was conducted at 2 academic centers and included 87 eyes in 67 patients who underwent cataract surgery between 2019 and 2021. Biometry measurements were obtained using a swept-source optical coherence tomography biometer (IOL Master 700). Refractive prediction errors, including root mean square error (RMSE), were calculated for 13 formulae. These included 4 classical formulae (Haigis, Hoffer Q, Holladay 1 [H1], and SRK/T), 5 new formulae (NF) (Barrett Universal II [BU2], Cooke K6, EVO 2.0, Kane, and Pearl-DGS), 3 KCN formulae (BU2 KCN: M-PCA, BU2 KCN: P-PCA, and Kane KCN), and H1 with equivalent keratometry reading values (H1-EKR). Formulae were ranked by RMSE. Friedman analysis of variance with post hoc analysis and H-testing was used for statistical significance testing. RESULTS KCN formulae had the lowest RMSEs in all eyes, and BU2 KCN:M-PCA performed the best among KCN formulae in all subgroups. In eyes with severe KCN, if TK values are unavailable, the BU2 KCN: P-PCA performed better than the top-ranked non-KCN formula (SRK/T). In eyes with nonsevere KCN, if TK values are unavailable, EVO 2.0 K was statistically superior to the next competitor (Kane K). H1-EKR had the highest RMSE. CONCLUSIONS KCN formulae and TK are useful for intraocular lens power calculations in KCN eyes, especially in eyes with severe KCN. The BU2 KCN: M-PCA using TK values performed best for eyes with all severities of KCN. For eyes with nonsevere KCN, the EVO 2.0 TK or K can also be used.
Collapse
Affiliation(s)
- Michael T Heath
- From the Dean McGee Eye Institute (M.T.H., R.P.P., D.A.M., K.M.R.), University of Oklahoma, Oklahoma City, Oklahoma; College of Medicine (M.T.H., R.P.P.), University of Oklahoma, Oklahoma City, Oklahoma
| | - Lakshman Mulpuri
- Bascom Palmer Eye Institute (L.M., E.K., H.L., R.S.T.), University of Miami, Miami, Florida
| | - Eden Kimiagarov
- Bascom Palmer Eye Institute (L.M., E.K., H.L., R.S.T.), University of Miami, Miami, Florida
| | - Raj P Patel
- From the Dean McGee Eye Institute (M.T.H., R.P.P., D.A.M., K.M.R.), University of Oklahoma, Oklahoma City, Oklahoma; College of Medicine (M.T.H., R.P.P.), University of Oklahoma, Oklahoma City, Oklahoma
| | - David A Murphy
- From the Dean McGee Eye Institute (M.T.H., R.P.P., D.A.M., K.M.R.), University of Oklahoma, Oklahoma City, Oklahoma
| | - Harry Levine
- Bascom Palmer Eye Institute (L.M., E.K., H.L., R.S.T.), University of Miami, Miami, Florida
| | - Rahul S Tonk
- Bascom Palmer Eye Institute (L.M., E.K., H.L., R.S.T.), University of Miami, Miami, Florida
| | - David L Cooke
- Great Lakes Eye Care (D.L.C.), Saint Joseph, Michigan; Department of Neurology and Ophthalmology (D.L.C.), College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA
| | - Kamran M Riaz
- From the Dean McGee Eye Institute (M.T.H., R.P.P., D.A.M., K.M.R.), University of Oklahoma, Oklahoma City, Oklahoma.
| |
Collapse
|
7
|
Wendelstein JA, Rothbächer J, Heath M, McDonald MC, Hoffmann PC, Cooke DL, Seiler TG, Langenbucher A, Riaz KM. Influence and predictive value of optional parameters in new-generation intraocular lens formulas. J Cataract Refract Surg 2023; 49:795-803. [PMID: 37097284 DOI: 10.1097/j.jcrs.0000000000001207] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/20/2023] [Indexed: 04/26/2023]
Abstract
PURPOSE To evaluate the accuracy of various variations of new-generation multivariate intraocular lens (IOL) power calculation using the Barrett Universal II, Castrop, Emmetropia Verifying Optical 2.0, Hill-Radial Basis Function 3.0, Kane, and PEARL-DGS formulas with and without optional biometric parameters. SETTING Tertiary care academic medical center. DESIGN Retrospective case series. Single-center study. METHODS Inclusion of patients after uneventful cataract surgery implanting AU00T0 IOLs. Data from one eye per patient were randomly included. Eyes with a corrected distance visual acuity worse than 0.1 logMAR were excluded. IOLCON-optimized constants were used for all formulas other than the Castrop formula. The outcome measures were prediction error (PE) and absolute prediction error (absPE) for the 6 study formulas. RESULTS 251 eyes from 251 patients were assessed. Excluding lens thickness led to statistically significant differences in absPE in several formulas. Leaving out horizontal corneal diameter did not impact absPE in several formulas. Differences in PE offset were observed between the various formula variations. CONCLUSIONS When using multivariate formulas with an A-constant, including certain optional parameters is vital for optimal refractive results. Formula variations excluding certain biometric parameters need specifically optimized constants and do not perform similarly when using the constant of the respective formula using all parameters.
Collapse
Affiliation(s)
- Jascha A Wendelstein
- From the Institut für Refraktive und Ophthalmochirurgie (IROC), Zurich, Switzerland (Wendelstein, Seiler); Department for Ophthalmology and Optometry, Kepler University Hospital GmbH, Linz, Austria (Wendelstein); Johannes Kepler University Linz, Medical Faculty, Linz, Austria (Wendelstein, Rothbächer); Institute of Experimental Ophthalmology, Saarland University, Homburg, Germany (Wendelstein, Langenbucher); Dean A. McGee Eye Institute/University of Oklahoma, Oklahoma City, Oklahoma (Heath, McDonald, Riaz); Augen-und Laserklinik, Castrop-Rauxel, Germany (Hoffmann); Great Lakes Eye Care, Saint Joseph, Michigan (Cooke); Department of Neurology and Ophthalmology, Michigan State University, College of Osteopathic Medicine, East Lansing, Michigan (Cooke)
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Ling JYM, Qiao G, Iovieno A, Yeung SN. Visual Outcomes of Cataract Surgery in Patients With Keratoconus Using Toric and Non-toric Lenses. J Refract Surg 2023; 39:319-325. [PMID: 37162398 DOI: 10.3928/1081597x-20230301-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
PURPOSE To compare the accuracy and outcomes of different intraocular lens (IOL) power calculation formulas in eyes with keratoconus undergoing cataract surgery with toric and non-toric IOLs. METHODS This was a consecutive retrospective case series study including patients from the Cornea Service at the Department of Ophthalmology and Visual Sciences at the University of British Columbia, Vancouver, Canada, from 2000 to 2020. Keratoconus was diagnosed based on corneal topography and clinician opinion. Patients who underwent topography-guided photorefractive keratectomy, intracorneal ring segments implantation, or corneal transplant were excluded. The manifest spherical equivalent, prediction errors, and median absolute errors were calculated. Descriptive statistics were expressed as mean ± standard deviation. RESULTS There were 160 eyes from 101 patients; 136 eyes received non-toric lenses and 24 eyes received toric lenses. Most patients had mild disease (< 48.00 diopters [D]) when stratified by steep keratometry values. Patients with severe disease (> 53.00 D) were significantly more hyperopic following surgery (P < .05). The Barrett Universal II (0.26 D, inter-quartile range [IQR] = 0.4), Holladay 2 (0.31, IQR = 1.2), and SRK/T (0.42, IQR = 0.86) formulas had the lowest median absolute error. The postoperative prediction error following toric lens insertion was not significantly different than following non-toric lens insertion, and the mean absolute astigmatism was significantly reduced with toric lenses. CONCLUSIONS The Barrett Universal II, Holladay 2, and SRK/T were the most accurate IOL power calculation formulas in patients with keratoconus undergoing cataract surgery. Hyperopic surprise was increased in severe keratoconus. Toric IOLs may be considered in patients with mild keratoconus. [J Refract Surg. 2023;39(5):319-325.].
Collapse
|
9
|
Pérez-Merino P, Aramberri J, Quintero AV, Rozema JJ. Ray tracing optimization: a new method for intraocular lens power calculation in regular and irregular corneas. Sci Rep 2023; 13:4555. [PMID: 36941337 PMCID: PMC10027892 DOI: 10.1038/s41598-023-31525-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/14/2023] [Indexed: 03/23/2023] Open
Abstract
To develop a novel algorithm based on ray tracing, simulated visual performance and through-focus optimization for an accurate intraocular lens (IOL) power calculation. Custom-developed algorithms for ray tracing optimization (RTO) were used to combine the natural corneal higher-order aberrations (HOAs) with multiple sphero-cylindrical corrections in 210 higher order statistical eye models for developing keratoconus. The magnitude of defocus and astigmatism producing the maximum Visual Strehl was considered as the optimal sphero-cylindrical target for IOL power calculation. Corneal astigmatism and the RMS HOAs ranged from - 0.64 ± 0.35D and 0.10 ± 0.04 μm (0-months) to - 3.15 ± 1.38D and 0.82 ± 0.47 μm (120-months). Defocus and astigmatism target was close to neutral for eyes with low amount of HOAs (0 and 12-months), where 91.66% of eyes agreed within ± 0.50D in IOL power calculation (RTO vs. SRK/T). However, corneas with higher amounts of HOAs presented greater visual improvement with an optimized target. In these eyes (24- to 120-months), only 18.05% of eyes agreed within ± 0.50D (RTO vs. SRK/T). The power difference exceeded 3D in 42.2% while the cylinder required adjustments larger than 3D in 18.4% of the cases. Certain amounts of lower and HOAs may interact favourably to improve visual performance, shifting therefore the refractive target for IOL power calculation.
Collapse
Affiliation(s)
- Pablo Pérez-Merino
- Centre for Microsystems Technology, Ghent University and Imec, Technologiepark 126, 9052, Ghent, Belgium.
| | - Jaime Aramberri
- Miranza Begitek, San Sebastian, Spain
- Miranza Okular, Vitoria, Spain
| | - Andrés Vásquez Quintero
- Centre for Microsystems Technology, Ghent University and Imec, Technologiepark 126, 9052, Ghent, Belgium
| | - Jos J Rozema
- Visual Optics Lab Antwerp (VOLANTIS), Faculty of Medicine and Health Sciences, University of Antwerp, Building T4, Universiteitsplein 1, 2610, Wilrijk, Belgium
- Department of Ophthalmology, Antwerp University Hospital, Wilrijkstraat 10, 2650, Edegem, Belgium
| |
Collapse
|
10
|
Alpins N, Ong JKY, Randleman JB, Stamatelatos G. Quantifying Corneal Topographic Astigmatism (CorT Total) in Keratoconic Eyes. J Refract Surg 2023; 39:206-213. [PMID: 36892237 DOI: 10.3928/1081597x-20230103-03] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
Abstract
PURPOSE To determine optimal corneal regions from which to derive corneal topographic astigmatism (CorT) in kerato-conic eyes. METHODS In this retrospective study, potential measures of corneal astigmatism are calculated from raw total corneal power data (179 eyes from 124 patients) from a corneal tomographer. The measures are derived from annular corneal regions varying in both extent and center position, and evaluated according to the variability of the ocular residual astigmatism (ORA) in the cohort. This variability is quantified by the ORArms, which is the root-mean-squared distance of the ORAs from their summated vector mean in double angle space. The lower the ORArms, the better the corneal astigmatism measure corresponds to manifest refractive cylinder. RESULTS Corneal astigmatism measures derived from regions centered on corneal vertex had ORArms values (mild: 1.07 diopters [D], moderate: 1.61 D, severe: 2.65 D) as low or lower than other measures derived from regions centered on thinnest point, corneal apex (front or back), or pupil center. Corneal astigmatism measures derived from a region centered 30% of the way toward thinnest point from corneal vertex appeared to have even lower ORArms values (mild: 1.05 D, moderate: 1.45 D, severe: 2.56 D). None of the corneal astigmatism measures corresponded closely with manifest refractive cylinder for severe keratoconus (ORArms > 2.50 D). CONCLUSIONS For keratoconic eyes, the CorT should be derived from an annular region centered 30% of the way toward thinnest point from corneal vertex, although when the keratoconus is mild, a standard corneal-vertex-centered CorT performs just as well. [J Refract Surg. 2023;39(3):206-213.].
Collapse
|
11
|
Vandevenne MM, Webers VS, Segers MH, Berendschot TT, Zadok D, Dickman MM, Nuijts RM, Abulafia A. Accuracy of intraocular lens calculations in eyes with keratoconus. J Cataract Refract Surg 2023; 49:229-233. [PMID: 36314969 PMCID: PMC9981321 DOI: 10.1097/j.jcrs.0000000000001088] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 10/20/2022] [Accepted: 10/21/2022] [Indexed: 11/05/2022]
Abstract
PURPOSE To compare the prediction accuracy of the Barrett True-K for keratoconus with standard formulas (SRK/T, Barrett Universal II, and Kane) and the Kane keratoconus formula. SETTING Shaare Zedek Medical Center, Jerusalem, Israel, and University Eye Clinic, Maastricht, the Netherlands. DESIGN Multicenter retrospective case series. METHODS Eyes with stable keratoconus undergoing cataract surgery were included. The predicted refractions were calculated for SRK/T, Barrett Universal II, Barrett True-K for keratoconus (predicted and measured), Kane, and Kane adjusted for keratoconus formulas. Primary outcomes were prediction error (PE), absolute error (AE), and percentage of eyes with PE ±0.25 diopters (D), ±0.50 D, and ±1.00 D. Subgroup analyses were performed based on the severity of the keratoconus. RESULTS 57 eyes were included in the study. The PE was not significantly different from zero for SRK/T, Barrett True-K (predicted and measured), and Kane keratoconus formulas (range 0.09 to 0.22 D, P > .05). The AE of Barrett True-K predicted (median 0.14 D) and Barrett True-K measured (median 0.10 D) were significantly lower from Barrett Universal II (median 0.47 D) and Kane (median 0.50 D), P < .001. CONCLUSIONS The Barrett True-K formulas for keratoconus had higher prediction accuracy as compared with new generation formulas and a similar prediction accuracy as compared with the Kane keratoconus formula.
Collapse
Affiliation(s)
- Magali M.S. Vandevenne
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Valentijn S.C. Webers
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Maartje H.M. Segers
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Tos T.J.M. Berendschot
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - David Zadok
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Mor M. Dickman
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Rudy M.M.A. Nuijts
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| | - Adi Abulafia
- From the University Eye Clinic, Maastricht University Medical Center+, Maastricht, the Netherlands (Vandevenne, Webers, Segers, Berendschot, Dickman, Nuijts); Department of Ophthalmology, Shaare Zedek Medical Center, Jerusalem, Israel (Zadok, Abulafia)
| |
Collapse
|
12
|
Singh C, Joshi VP. Cataract surgery in Keratoconus revisited - An update on preoperative and intraoperative considerations and postoperative outcomes. Semin Ophthalmol 2023; 38:57-64. [PMID: 35996343 DOI: 10.1080/08820538.2022.2112702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE This review aims to evaluate and simplify the recent literature on preoperative surgical planning, intraoperative considerations, postoperative surprises, and their management in patients with keratoconus undergoing cataract surgery. METHODS A review of the literature was done to analyze all the pertinent articles on Keratoconus and cataract surgery. RESULTS The surgical planning of cataracts in eyes with keratoconus needs a multifaceted approach. Preoperatively, techniques such as cross-linking or the use of intra-corneal rings help stabilize the progression. Unreliable biometric measurements are a significant problem in keratoconus patients, especially in an advanced stage of the disease. It is better to consider actual K readings if the K value is less than 55D but for a K value, more than 55D using standard K values will prevent postoperative refractive surprises. For calculation of K values, an elevation-based device like pentacam gives better repeatability in mild to moderate cases whereas for advanced keratoconus none of the keratometers is reliable. Recently, the Kane keratoconus formula performed better in all stages of disease whereas previous studies showed good results with SRK/T formula is a mild and moderate disease. Monofocal intraocular lenses are a better choice in these patients. Toric lenses can be used in mild and stable keratoconus. Intraoperatively, the use of a customized RGP lens can overcome the challenge of image distortion and loss of visual perspective. Despite taking necessary measures, postoperative refractive surprise can occur and can be managed with IOL exchange or Secondary IOLs. CONCLUSION There is a spectrum of challenges in managing cataracts in keratoconus which makes thorough preoperative planning important for good surgical outcomes. Despite the measures, there might be post-operative surprises and the patients need to be informed regarding the same.
Collapse
Affiliation(s)
- Charul Singh
- Academy of Eye Care Education, L V Prasad Eye Institute, Hyderabad, India.,The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Vineet P Joshi
- The Cornea Institute, L V Prasad Eye Institute, Hyderabad, India.,Centre for Innovation, L V Prasad Eye Institute, Hyderabad, India
| |
Collapse
|
13
|
Cataract surgery considerations in patients with prior history of keratoconus and ectasia. Curr Opin Ophthalmol 2023; 34:41-47. [PMID: 36165405 DOI: 10.1097/icu.0000000000000908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Preoperative workup for cataract surgery in patients with keratoconus poses certain challenges, particularly in patients with moderate-to-severe disease. This review aims to outline the appropriate preoperative, intraoperative, and postoperative considerations and provides an algorithm to help guide the workup prior to surgery. RECENT FINDINGS A new system for keratoconus progression and staging has been proposed and additional studies comparing intraocular lens (IOL) formulas calculations and biometry devices have been conducted. SUMMARY Patients with severe keratoconus have unpredictable results and have an increased risk of a hyperopic refraction postoperatively. Although studies have compared IOL calculation formulas, there is no consensus on management. Clinical considerations and an approach to the workup are presented; however, additional studies are required to determine the most appropriate management of cataracts in severe keratoconus.
Collapse
|
14
|
Gonzalez-Salinas R, Franco JJ, Reyes-Luis JL, Sánchez-Huerta V, de Wit-Carter G, Hernández-Quintela E, Pineda R. Cataract surgery in patients with underlying keratoconus: focused review. J Cataract Refract Surg 2023; 49:97-102. [PMID: 36194107 DOI: 10.1097/j.jcrs.0000000000001069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 09/24/2022] [Indexed: 11/07/2022]
Abstract
An underlying diagnosis of keratoconus (KC) can complicate cataract surgery. In this study, the results of a focused review of the literature pertaining to cataract surgery in patients with KC are detailed. Topics essential for the appropriate management of this patient population are discussed. First, the individual and shared epidemiology and pathophysiology of cataract and KC are reviewed. Then, the theory and approach to intraocular lens power calculation are discussed, highlighting particularities and pitfalls of this exercise when performed in patients with KC. Finally, several special-although not uncommon-management scenarios and questions are addressed, such as surgical planning in cases where corneal stabilization or tissue replacement interventions are also necessitated.
Collapse
Affiliation(s)
- Roberto Gonzalez-Salinas
- From the Anterior Segment Surgery Department, Asociación para Evitar la Ceguera I.A.P., Mexico City, Mexico (Gonzalez-Salinas); Harvard Medical School, Boston, Massachusetts (Franco, Pineda); Cornea and Refractive Surgery Service, Massachusetts Eye and Ear, Boston, Massachusetts (Reyes-Luis, Pineda); Cornea Department, Asociación para Evitar la Ceguera I.A.P., Mexico City, Mexico (Sánchez-Huerta, de Wit-Carter); Division of Comprehensive Ophthalmology, Wilmer Eye Institute, Johns Hopkins Medicine, Baltimore, Maryland (Hernández-Quintela)
| | | | | | | | | | | | | |
Collapse
|
15
|
Evaluation of IOL power calculation with the Kane formula for pediatric cataract surgery. Graefes Arch Clin Exp Ophthalmol 2022; 260:2877-2885. [PMID: 35895106 DOI: 10.1007/s00417-022-05779-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 06/07/2022] [Accepted: 07/19/2022] [Indexed: 11/04/2022] Open
Abstract
PURPOSE To assess the accuracy of the Kane formula for intraocular lens (IOL) power calculation in the pediatric population. METHODS The charts of pediatric patients who underwent cataract surgery with in-the-bag IOL implantation with one of two IOL models (SA60AT or MA60AC) between 2012 and 2018 in The Hospital for Sick Children, Toronto, Ontario, CanFada, were retrospectively reviewed. The accuracy of IOL power calculation with the Kane formula was evaluated in comparison with the Barrett Universal II (BUII), Haigis, Hoffer Q, Holladay 1, and Sanders-Retzlaff-Kraff Theoretical (SRK/T) formulas. RESULTS Sixty-two eyes of 62 patients aged 6.2 (IQR 3.2-9.2) years were included. The SD values of the prediction error obtained by Kane (1.38) were comparable with those by BUII (1.34), Hoffer Q (1.37), SRK/T (1.40), Holaday 1 (1.41), and Haigis (1.50), all p > 0.05. A significant difference was observed between the Hoffer Q and Haigis formulas (p = 0.039). No differences in the median and mean absolute errors were found between the Kane formula (0.54 D and 0.91 ± 1.04 D) and BUII (0.50 D and 0.88 ± 1.00 D), Hoffer Q (0.48 D and 0.88 ± 1.05 D), SRK/T (0.72 D and 0.97 ± 1.00 D), Holladay 1 (0.63 D and 0.94 ± 1.05 D), and Haigis (0.57 D and 0.98 ± 1.13 D), p = 0.099. CONCLUSION This is the first study to investigate the Kane formula in pediatric cataract surgery. Our results place the Kane among the noteworthy IOL power calculation formulas in this age group, offering an additional means for improving IOL calculation in pediatric cataract surgery. The heteroscedastic statistical method was first implemented to evaluate formulas' predictability in children.
Collapse
|
16
|
Achiron A, Elhaddad O, Leadbetter D, Levinger E, Voytsekhivskyy O, Smith K, Avadhanam V, Darcy K, Tole D. Intraocular lens power calculation in patients with irregular astigmatism. Graefes Arch Clin Exp Ophthalmol 2022; 260:3889-3895. [PMID: 35776172 DOI: 10.1007/s00417-022-05729-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 05/07/2022] [Accepted: 06/07/2022] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Accurate intraocular lens (IOL) calculation in subjects with irregular astigmatism is challenging. This study evaluated the accuracy of using Scheimpflug-derived central 2-mm equivalent keratometry reading (EKR) values for IOL calculation in irregular astigmatism. METHODS This retrospective study included subjects (31 eyes of 30 patients) who underwent cataract surgery and IOL calculation using the 2-mm central EKR methods. We compared prediction error (PE) and absolute PE (APE) outcomes using SRK/T and Barrett Universal II formulas for keratometry data obtained from the IOLMaster 500 and Pentacam (anterior corneal sim k) devices. RESULTS Cataract surgery and IOL calculation using the 2-mm central EKR methods resulted in improved visual acuity (uncorrected: from 1.13 ± 0.38 to 0.65 ± 0.46 logMar, p < 0.01; best-corrected: from 0.45 ± 0.24 to 0.26 ± 0.20 logMar, p < 0.01) after surgery. The percentage of subjects with best-corrected visual acuity of 6/6 was 22%, < 6/9 was 58%, and < 6/12 was 71%. For both the SRK/T and the Barrett formulas, the PE was similar to those obtained by IOLMaster (> 0.14) but lower than those obtained by the anterior corneal sim k (p < 0.02). IOLMaster provided keratometry reading in only 23/31 (74.1%) of cases. CONCLUSIONS The use of Scheimpflug central 2-mm EKR for IOL calculation in irregular astigmatism was beneficial in terms of visual acuity improvement. It had comparable refractive prediction performance to the IOLMaster 500 and better than the anterior corneal sim K. The 2-mm EKR method can be used when IOLMaster cannot provide a reliable reading in abnormal corneas.
Collapse
Affiliation(s)
- Asaf Achiron
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK.
- Sourasky Tel-Aviv Medical Center and the Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - Omar Elhaddad
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
- Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Duncan Leadbetter
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
| | - Eliya Levinger
- Sourasky Tel-Aviv Medical Center and the Sackler Faculty of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Katy Smith
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
| | - Venkata Avadhanam
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
| | - Kieren Darcy
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
| | - Derek Tole
- Bristol Eye Hospital, University Hospitals Bristol NHS Foundation Trust, Lower Maudlin St, Bristol, BS1 2LX, UK
| |
Collapse
|
17
|
New treatment algorithm for keratoconus and cataract: small-aperture IOL insertion with sequential topography-guided photorefractive keratectomy and simultaneous accelerated corneal crosslinking. J Cataract Refract Surg 2021; 47:1411-1416. [PMID: 34675148 DOI: 10.1097/j.jcrs.0000000000000642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 03/05/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe a new treatment algorithm aimed at optimizing refractive outcomes for patients with keratoconus and cataract. SETTING Private practice in Sydney, Australia. DESIGN Retrospective case series. METHODS This procedural approach involves cataract extraction with small-aperture intraocular lens (IOL) insertion, IC-8 IOL (AcuFocus, Inc.), followed by topography-guided photorefractive keratectomy (T-PRK) with simultaneous corneal crosslinking (CXL). Cataract surgery was performed with an initial 2.4 mm clear corneal incision enlarged to 3.5 mm to accommodate IC-8 IOL insertion. Once eyes demonstrated stable corneal tomography and refraction, T-PRK was performed using Schwind excimer laser (500 Hz) with the Vancouver custom topographical neutralization technique, aiming to achieve low myopia. CXL was performed immediately after T-PRK using Optolink hypotonic riboflavin with LIGHTLink-CXL (Lightmed) with 5.4 J total energy delivered at an 18 mw/cm2 irradiance. RESULTS Outcomes of 4 eyes are reported with all achieving rigid gas-permeable (RGP) contact lens independence, improved corrected distance visual acuity (CDVA) and uncorrected distance visual acuity (UDVA), and regularization of corneal curvature with cone reduction. The mean CDVA improved from 0.43 preoperatively to 0.07 postoperatively (P = .00), and the mean UDVA improved from 0.81 preoperatively to 0.29 postoperatively (P = .04). Postoperative UNVA ranged from N.8 to N.12. CONCLUSIONS This treatment algorithm demonstrates unique combination of existing corneal and cataract surgical procedures to achieve satisfactory refractive outcomes and RGP contact lens independence in patients with keratoconus and cataract.
Collapse
|
18
|
Hou M, Ding Y, Liu L, Li J, Liu X, Wu M. Accuracy of intraocular lens power calculation in primary angle-closure disease: comparison of 7 formulas. Graefes Arch Clin Exp Ophthalmol 2021; 259:3739-3747. [PMID: 34258655 DOI: 10.1007/s00417-021-05295-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/08/2021] [Accepted: 06/22/2021] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To assess the accuracy of intraocular lens power calculation formulas Barrett Universal II (BUII), Hill-Radial Basis Function (RBF) 3.0, Kane, Ladas Super Formula (LSF), Haigis, Hoffer Q, and SRK/T in primary angle-closure disease (PACD). METHODS A total of 129 PACD eyes were enrolled. Prediction refraction was calculated for each formula and compared with actual refraction. Accuracy was determined by formula performance index (FPI), median absolute error (MedAE) and percentage of eyes with a prediction error (PE) within ± 0.50D. Subgroup analysis was performed according to axial length (AL). RESULTS Overall, FPI was ranked as follows: Kane (0.067), RBF 3.0 (0.064), Haigis (0.062), SRK/T (0.060), BUII (0.058), Hoffer Q (0.055), and LSF (0.049). Kane got the highest (71.3%) percentage of eyes with PE within ± 0.50 D. In medium AL eyes (22 mm < AL ≤ 25 mm), FPI ranked the same as in total group. MedAEs were equal across all formulas (P = 0.121). In short eyes (AL ≤ 22 mm), FPI was Kane (0.055), RBF 3.0 (0.050), SRK/T (0.050), Haigis (0.049), BUII (0.047), Hoffer Q (0.045), and LSF (0.033). MedAEs were significantly different across all formulas (P = 0.033). Haigis showed the lowest MedAE (0.35 D), Haigis and Kane got the highest percentage (63.6%) of eyes with PE within ± 0.50 D. CONCLUSION Kane outperformed in total PACD eyes; RBF 3.0, Haigis, and SRK/T achieved satisfying performance. When dealing with PACD eyes shorter than 22 mm, Kane achieved the best accuracy. RBF 3.0, SRK/T, Haigis, and BUII achieved comparable outcomes. No formula showed superiority over others for medium AL PACD eyes.
Collapse
Affiliation(s)
- Min Hou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China
| | - Yujie Ding
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China
| | - Liangping Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China
| | - Jianbing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China
| | - Xing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China
| | - Mingxing Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, No.7 Jinsui Road, Guangzhou, People's Republic of China.
| |
Collapse
|
19
|
Camps VJ, Riad RRF, Caravaca-Arens E, Labib FE, Mateo V, Caballero MT, Piñero DP. Comparison of Four Intraocular Power Calculation Formulas in Keratoconus Eyes. Open Ophthalmol J 2021. [DOI: 10.2174/1874364102115010096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Introduction:
This study aimed to evaluate the differences in Intraocular Lens (IOL) power in keratoconus (KC) eyes between calculations obtained clinically with the most commonly used formulas in healthy eyes (SRK T, Holladay 1, Hoffer Q and Haigis) as well as to define predictive factors for such differences.
Methods:
This retrospective study comprised 43 keratoconus eyes of 22 patients with no previous ocular surgery. IOL powers were calculated with SRK T, Holladay 1, Hoffer Q, and Haigis formulas, considering the Effective Lens Position (ELP) of each formula and the desired refraction of 0 D (Rdes=0 D).
Results:
All differences between formulas were statistically significant and clinically relevant. Haigis formula always provided higher values compared to the rest of the formulas, with the highest differences observed when comparing Haigis with Hoffer (0.84 D) and Hoffer Q (1.17 D) formulas. The lowest difference was obtained for the comparison between SRK-T and Holladay 1 formulas (0.22 D). Differences of the Haigis formula compared to the rest were higher as the magnitude of the IOL power calculated decreased, becoming the patient more myopic. Increased differences between Haigis and Hoffer formulas were observed in eyes with deep anterior chambers, steeper anterior and posterior corneal surfaces, and high axial lengths.
Conclusion:
The most comparable results in IOL power in keratoconus are provided by the Holladay 1 and SRK T formulas, whereas the Haigis formula provides the most discrepant outcome. The consideration of the curvature of the second corneal surface in IOL power calculations in keratoconus may decrease the variability between calculation methods. However, other factors as anterior chamber depth or axial length are also relevant.
Collapse
|
20
|
Priji P, Jacob SC, Kalikivayi L, Kalikivayi V. Correlating Kane formula with existing intraocular lens formulae for corneal curvatures and axial lengths. Oman J Ophthalmol 2021; 14:94-99. [PMID: 34345143 PMCID: PMC8300291 DOI: 10.4103/ojo.ojo_62_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 05/19/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND: To evaluate the predictability of the Kane formula in estimating postoperative refractive outcome with various corneal curvatures and axial lengths (ALs) besides comparing with existing intraocular lens (IOL) formulae. MATERIALS AND METHODS: A prospective cross-sectional study was carried out among patients having uneventful cataract surgery at an eye hospital. A total of 50 eyes were considered for the study. The corresponding A-constant for the model of IOL implanted into the patient's eye was taken along with the actual power of IOL implanted and corresponding predicted power for the IOL power inserted were taken for all the chosen formulae and was termed as "Adjusted Predicted Refractive Power." This was compared with the actual refractive outcome and the absolute error (AE) was measured. The eyes were separated into groups in terms of corneal curvature as flat (<42D), medium (42D–46D), and steep (>46D) corneas. In terms of AL, it was grouped as short (≤22 mm), medium (>22.0–<24.0 mm), and long (>24.0 mm) eyes. RESULTS: The study included 50 eyes and the mean AE for all the selected formulae were calculated for each group. Over the entire corneal curvature range, none of the formulae showed any significance when compared with the Kane formula (P > 0.05). In short AL, SRK-T formula had a statistical significance over the Kane formula (P = 0.043), whereas no other group had any significance over the Kane formula in AL groups. CONCLUSION: The study shows, all formulae (SRK-T, Holladay1, Hoffer Q, Hill RBF, Barrett Universal II, Kane) are interchangeable to predict the IOL power for any of the corneal curvature and ALs.
Collapse
Affiliation(s)
- P Priji
- Ahalia School of Optometry, Palakkad, Kerala, India
| | - Sajeev Cherian Jacob
- Ahalia School of Optometry, Palakkad, Kerala, India.,Ahalia Foundation Eye Hospital, Palakkad, Kerala, India
| | | | | |
Collapse
|
21
|
Li Y, Gokul A, McGhee C, Ziaei M. Repeatability and agreement of biometric measurements using spectral domain anterior segment optical coherence tomography and Scheimpflug tomography in keratoconus. PLoS One 2021; 16:e0248659. [PMID: 34019547 PMCID: PMC8139453 DOI: 10.1371/journal.pone.0248659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 04/30/2021] [Indexed: 11/25/2022] Open
Abstract
Purpose To compare the repeatability and agreement in biometric measurements using Spectral Domain Anterior Segment OCT (AS-OCT, REVO-NX, Optopol) and Scheimpflug tomography (Pentacam-AXL, Oculus) in keratoconus. Methods Prospective case series at a university hospital tertiary center. Axial length (AL), anterior chamber depth (ACD), central corneal thickness (CCT), and thinnest corneal thickness (TCT) were measured using both devices in patients with keratoconus. Three groups were analyzed: eyes with no prior crosslinking or contact lens wear (Group A), eyes with prior crosslinking (Group B), and eyes with prior contact lens wear (Group C). Repeatability and agreement of measurements were analyzed. Results The study comprised of 214 eyes of 157 subjects. In Group A (n = 95 eyes), Group B (n = 86 eyes), and Group C (n = 33 eyes), intraclass correlation coefficient (ICC) was higher than 0.90 for all examined parameters, except for ACD readings in Group A with the REVO-NX (ICC = 0.83). Differences in ACD, TCT, and CCT were significantly different between the two devices for Groups A, B and C (p<0.05). AL measurements differed significantly in Groups A and B (p<0.05) but not in Group C (p = 0.18). Repeatability did not vary significantly between Groups A, B, or C in any parameter with both devices (p>0.05). There was poor agreement between the two devices across all parameters (p<0.05). Conclusions Both devices demonstrated good repeatability but poor agreement across AL, ACD, CCT and TCT measurements. There was no significant difference in repeatability in virgin eyes compared to eyes with prior crosslinking or contact lens wear, however, the interchangeable use of the two devices is not recommended.
Collapse
Affiliation(s)
- Ye Li
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Akilesh Gokul
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Charles McGhee
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Mohammed Ziaei
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- * E-mail:
| |
Collapse
|
22
|
Toric intraocular lens power calculation in cataract patients with keratoconus. J Cataract Refract Surg 2021; 47:1389-1397. [PMID: 33770295 DOI: 10.1097/j.jcrs.0000000000000638] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/03/2021] [Indexed: 11/26/2022]
Abstract
Purpose Intra-ocular lens (IOL) power calculation in eyes with keratoconus typically results in hyperopic postoperative refractive error. We investigated the visual and refractive outcomes in keratoconus patients having cataract surgery with a toric IOL and compared IOL power calculation accuracy of conventional formulae and keratoconus specific formulae. Setting Ein-Tal Eye Center, Tel-Aviv, Israel. Design Retrospective case-series study. Methods Post-operative visual acuity and manifest refraction were examined. The error in predicted refraction and IOL power calculation accuracy within a range of 0.5 to 2.0 diopters were compared between different IOL calculating formulae. Results Thirty-two eyes with keratoconus were included. Visual acuity improved in all cases and subjective astigmatism decreased from -2.95+/-2.10 D to -0.95+/-0.80 D (p<0.001). Mean absolute errors were: Barrett True-K for keratoconus with measured or predicted posterior corneal power, 0.34 D; Barrett Universal II, 0.64 D; Kane Formula, 0.69 D; Kane Formula for keratoconus, 0.49 D; SRK/T, 0.56 D; Haigis, 0.72 D; Holladay 1, 0.71 D and Hoffer Q, 0.87 D. Barrett True-K formula with measured posterior corneal power, SRK/T and Kane Formula for keratoconus resulted in a prediction error within 0.5 D of 87.5%, 59.4% and 53.1%, respectively. Conclusions Cataract removal with a toric IOL significantly improves visual acuity and decreases astigmatism in keratoconic eyes with a topographic central relatively regular astigmatic component. Keratoconus specific formulae resulted in lower mean error in predicted refraction compared with conventional calculating formulae. Utilizing the posterior corneal power within the Barrett True K formula for keratoconus improved IOL power prediction accuracy.
Collapse
|
23
|
Re: Kane et al.: Accuracy of intraocular lens power formulas modified for patients with keratoconus (Ophthalmology. 2020;127:1037-1042). Ophthalmology 2020; 128:e12-e13. [PMID: 33129582 DOI: 10.1016/j.ophtha.2020.09.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/05/2020] [Accepted: 09/09/2020] [Indexed: 11/21/2022] Open
|
24
|
Wang KM, Jun AS, Ladas JG, Siddiqui AA, Woreta F, Srikumaran D. Reply to Comment on: Accuracy of Intraocular Lens Formulas in Eyes With Keratoconus. Am J Ophthalmol 2020; 218:355-356. [PMID: 32620263 DOI: 10.1016/j.ajo.2020.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 11/20/2022]
Affiliation(s)
- Kendrick M Wang
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Albert S Jun
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - John G Ladas
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Maryland Eye Consultants and Surgeons, Silver Spring, Maryland
| | - Aazim A Siddiqui
- Department of Ophthalmology and Visual Sciences, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York
| | - Fasika Woreta
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Divya Srikumaran
- Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| |
Collapse
|
25
|
Gonzalez-Lubcke E, Kahuam-Lopez N, Navas A, Ramirez-Miranda A, Graue-Hernandez EO. Comment on: Accuracy of Intraocular Lens Formulas in Eyes With Keratoconus. Am J Ophthalmol 2020; 218:354-355. [PMID: 32646542 DOI: 10.1016/j.ajo.2020.04.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 10/23/2022]
|