Comparative clinical accuracy analysis of the newly developed ZZ IOL and four existing IOL formulas for post-corneal refractive surgery eyes

Zhang, Jun; Shao, Jie; Li, Zheng; Shen, Ye; Zhao, Xia

doi:10.1186/s12886-021-01991-7

Cited by 4 publications

(4 citation statements)

References 36 publications

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“…Also, ray tracing allows corneal aberrations to be included in the IOL calculations [ 2 , 21 ]. Unfortunately, so far, ray tracing has shown controversial results in the literature and is not yet widely available [ 22 , 23 ].…”

Section: Discussionmentioning

confidence: 99%

A Novel Role for Corneal Pachymetry in Planning Cataract Surgery by Determining Changes in Spherical Equivalent Resulting from a Previous LASIK Treatment

Hammer

Heeren

Angunawela

et al. 2023

Journal of Ophthalmology

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Objectives. To provide a metric to differentiate between hyperopic and myopic ablation of a prior LASIK treatment based on the corneal pachymetry profile after laser vision correction (LVC). Methods. Pachymetry data were retrospectively recovered from patients who had previous LASIK for refractive purposes between 2019 and 2020. Patients with any corneal disorder were excluded. Ablation spherical equivalent was predicted from the central to semiperipheral corneal thickness (CPT) ratio, both values were provided by using the Pentacam user interface software (UI), and values were computed from extracted raw pachymetry data. Results. Data of 157 eyes of 81 patients were collected, of which data were analysed for 73 eyes of 73 patients to avoid concurrence of measurements in both eyes per subject (42% female; mean age 40.9; SD 12.8). The CPT ratio cutoff for distinction between myopic and hyperopic LASIK was 0.86 for Pentacam UI data. Sensitivity and specificity were 0.7 and 0.95, respectively. Accuracy increased with computation of the CPT ratio based on extracted raw data with sensitivity and specificity of 0.87 and 0.99, respectively. There was a marked linear correlation between the CPT ratio and the ablation spherical equivalent (R2 = 0.93). Conclusions. CPT ratio cutoffs can correctly classify if a cornea previously had a hyperopic versus myopic LASIK surgery and estimate the ablation spherical equivalent of such treatment. This could prove useful for increased accuracy of intraocular lens (IOL) calculations for patients with no historical data of their prior LVC surgery at the time of cataract surgery planning.

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Section: Discussionmentioning

confidence: 99%

A Novel Role for Corneal Pachymetry in Planning Cataract Surgery by Determining Changes in Spherical Equivalent Resulting from a Previous LASIK Treatment

Hammer

Heeren

Angunawela

et al. 2023

Journal of Ophthalmology

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“…The IOL calculation was carried out utilizing the Zhang & Zheng IOL power formula (ZZ IOL), which was distinct from conventional or AI-driven approaches, and functioning as a ray-tracing-based formula. 14 The chosen IOL power aimed to achieve emmetropia. Eyes with preoperative regular corneal astigmatism >1.00D were suitable candidates for PanOptix Toric T3-T6 IOLs, with a predicted residual astigmatism of <0.50D.…”

Section: Methodsmentioning

confidence: 99%

Visual Outcomes and Patient Satisfaction of Trifocal or Trifocal Toric IOLs in Chinese Cataract Patients: Focus on Near Vision at 33 cm

Cao,

Shao,

Zhang

et al. 2024

OPTH

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Purpose To examine the visual outcomes, particularly at 33 cm, and assess patient satisfaction following the implantation of a diffractive trifocal intraocular lens (IOL) and its toric variant. Patients and Methods This prospective single-arm observational study involved 45 Chinese patients (90 eyes) underwent bilateral cataract surgery and PanOptix or PanOptix toric intraocular lenses (IOLs) implantation. Postoperatively, visual acuity was evaluated at various distances, including 40 cm and 33 cm, for both monocular and binocular outcomes. Patient satisfaction was evaluated using the VF-14 questionnaire. Results 72 eyes underwent PanOptix IOLs implantation, and 18 eyes received PanOptix toric IOLs. At 3-month postoperative mark, the mean monocular UDVA, UIVA, and UNVA at 40 cm and 33 cm were −0.02±0.09, 0.00±0.07, 0.02±0.07, and 0.07±0.14 logMAR, respectively, with proportions of visual acuity exceeding 0.1 logMAR were 96.7%, 96.7%, 94.4%, and 74.4%, respectively. The mean binocular UDVA, UIVA, and UNVA at 40 cm and 33 cm were −0.05±0.06, −0.03±0.05, 0.00±0.05, and 0.04±0.07 logMAR, respectively, with proportions of visual acuity exceeding 0.1 logMAR were 97.8%, 100.0%, 100.0%, and 91.1%, respectively. When the near point shifted from 40cm to 33cm, some patients showed a decline for UDVA, but the average reduction was less than one line. The overall VF-14 questionnaire score was 4.02±4.19. Conclusion PanOptix can provide Chinese patients with a full range of satisfying visual acuity, near to 33cm. Though the visual acuity of some patients at 33 cm did not match the level at 40 cm, the gap of one line may not carry clinical significant.

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“…The Zhang & Zheng (ZZ) formula is a newly-developed intraocular lens (IOL) calculation formula that has shown promising results in clinical accuracy analysis for post-corneal refractive surgery eyes [81]. They compared the precision of the ZZ, Haigis-L, Shammas, Barrett True-K (no history), and ray tracing (C.S.O Sirius) IOL power assessments in eyes that had undergone corneal refractive surgery.…”

Section: Post-refractive Surgery Eyesmentioning

confidence: 99%

Evolution of Biometric Formulas and Intraocular Lens Selection in Challenging Cases

Karataş,

Aslı Utine

2023

Cataract - An Update on Clinical and Surgical Management

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Various novel intraocular lens (IOL) power calculation formulas have been described to increase refractive precision following cataract surgery. These include the Barrett Universal II, Emmetropia Verifying Optical (EVO), Kane, Naeser 2, Olsen, Panacea, Pearl DGS, Radial Basis Function (RBF), T2, and VRF formulas. With a few notable exceptions, historical and regression formulas—first- and second-generation IOL formulas like Sanders, Retzlaff, Kraff (SRK), Binkhorst, Hoffer, and SRKII—are generally regarded as outdated. The effective lens position (ELP) is accounted for in third- and fourth-generation formulas which include more biometric data. A possible alternative that has shown to be remarkably accurate when used with the Olsen method is ray tracing. Artificial intelligence-derived IOL formulas are becoming increasingly common and may yield better lens power prediction accuracy. Despite improvements in surgical technique, biometry measurements, and IOL calculations, some clinical circumstances continue to challenge cataract surgeons to determine the appropriate IOL power. These unique situations include pediatric eyes, post-refractive eyes, and corneal ectasias. The obstacles to reliability include unrepeatable measurements and inaccurate biometry examinations. Researchers have tried to identify the most accurate IOL estimations for these challenging clinical scenarios to overcome these obstacles.

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Comparative clinical accuracy analysis of the newly developed ZZ IOL and four existing IOL formulas for post-corneal refractive surgery eyes

Cited by 4 publications

References 36 publications

A Novel Role for Corneal Pachymetry in Planning Cataract Surgery by Determining Changes in Spherical Equivalent Resulting from a Previous LASIK Treatment

A Novel Role for Corneal Pachymetry in Planning Cataract Surgery by Determining Changes in Spherical Equivalent Resulting from a Previous LASIK Treatment

Visual Outcomes and Patient Satisfaction of Trifocal or Trifocal Toric IOLs in Chinese Cataract Patients: Focus on Near Vision at 33 cm

Evolution of Biometric Formulas and Intraocular Lens Selection in Challenging Cases

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