Comparison of 6.0 mm versus 6.5 mm Optical Zone on Visual Outcomes after LASIK

Moshirfar, Majid; Huynh, Rachel; Bundogji, Nour; Tukan, Alyson N; Sant, Thomas M.; McCabe, Shannon E; West, William B.; Drennan, Kirk; Ronquillo, Yasmyne C; Hoopes, Phillip C

doi:10.3390/jcm10173776

Cited by 4 publications

(1 citation statement)

References 25 publications

(27 reference statements)

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“…Also, as previously described in the literature, most treatment planning systems of excimer lasers use optical zones ranging between 6 and 6.5 mm with a general trend toward larger optical zones. Tose are comparable to the optical zones used in this study [32][33][34][35]. Terefore, the principle of the CPT ratio may be applied to excimer lasers from other manufacturers than the one used in this study.…”

Section: Discussionmentioning

confidence: 89%

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: 89%

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 effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis

et al. 2023

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Influence of optical zone on myopic correction in small incision lenticule extraction: a short-term study

Liu

Zhang

et al. 2022

BMC Ophthalmol

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Background: To evaluate the influence of preoperative optical zone on myopic correction in small incision lenticule extraction. Methods: In this retrospective clinical study, 581 eyes from 316 patients underwent SMILE were selected, including 117 eyes in the small optical zone group (range from 6.0 to 6.4 mm) and 464 eyes in the large optical zone group (range from 6.5 to 6.8 mm). The measurements included uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical, and cylinder were measured preoperatively and 3 months postoperatively. Propensity score match (PSM) analysis was performed with age, gender, eye (right/left), keratometry and preoperative spherical equivalent between two different groups. The influence of optical zones on postoperative refractive outcomes were evaluated using univariate regression analysis. Results: In total, 78 pairs of eyes were selected by PSM (match ratio 1:1). There were no differences in the age, gender, eye (right/left), keratometry or preoperative spherical equivalent between the small and large optical zone groups. However, the difference of postoperative spherical equivalent was significantly between groups. Patients with larger optical zones had a trend towards less undercorrection (P = 0.018). Univariate linear regression model analysis found that each millimeter larger optical zone resulted in 8.13% or 0.39D less undercorrection (P < 0.001). The dependency between the optical zones and postoperative spherical equivalent was significant in the higher preoperative myopia group (r = 0.281, P < 0.001), but not significant in the lower myopia group (r = 0.028, P = 0.702). Conclusion: The diameter of optical zones would affect postoperative refractive outcomes in small incision lenticule extraction. This study indicated that larger optical zones induced less undercorrection, especially in patients with high myopia.

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Comparison of 6.0 mm versus 6.5 mm Optical Zone on Visual Outcomes after LASIK

Cited by 4 publications

References 25 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

The effects of programmed optical zones on achieved corneal refractive power with myopic astigmatism after small incision lenticule extraction (SMILE): a vector analysis

Influence of optical zone on myopic correction in small incision lenticule extraction: a short-term study

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