Transepithelial photorefractive keratectomy to treat mild myopia

2021 ◽  
Author(s):  
Mohammed Alasmari ◽  
Abdullah M. Alfawaz
Keyword(s):  
Photorefractive Keratectomy

Smile technology in the correction of residual myopia after photorefractive keratectomy

2020 ◽  
pp. 333-334
Author(s):  
O.V. Pisarevskaya ◽  
◽  
T.N. Iureva ◽  
A.G. Shchuko ◽  
E.P. Ivleva ◽  
...  
Keyword(s):  
Photorefractive Keratectomy

Transepithelial photorefractive keratectomy on the same day of the initial consultation for the correction of myopia

2021 ◽  
pp. 112067212110334
Author(s):  
Olga Reitblat ◽  
Assaf Gershoni ◽  
Michael Mimouni ◽  
Eitan Livny ◽  
Yoav Nahum ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Clinical Outcomes ◽  
Photorefractive Keratectomy ◽  
Spherical Equivalent ◽  
Initial Visit ◽  
Safety Outcome ◽  
Uncorrected Visual Acuity ◽  
Safety Indices

Purpose: To examine the clinical outcomes, efficacy, safety, and predictability of transepithelial photorefractive keratectomy (Trans-PRK) operations performed on the day of the first screening visit in comparison with operations scheduled at a following appointment. Methods: Data of consecutive patients with myopia of various degrees, who underwent Trans-PRK, were retrospectively analyzed. Findings were compared between patients who underwent Trans-PRK on the same day of first consultation to patients that underwent surgery at subsequent visits, following initial consultation on a different day. Results: The study included 599 eyes treated on the initial visit day and 1936 eyes treated on a subsequent visit. Mean final spherical equivalent was close to emmetropia in both groups ( p = 0.183). Efficacy indices were 0.928 ± 0.192 in the initial-visit group and 0.945 ± 0.163 in the second-visit group ( p = 0.152). Safety indices were 0.954 ± 0.156 and 0.955 ± 0.151 ( p = 0.707), respectively. No differences between the groups were seen in uncorrected visual acuity (UDVA) of ⩾20/20, ⩾20/25, and ⩾20/32. Only the sub-analysis of patients reaching UDVA of 20/40 or better was slightly lower in the first-visit (95.5%) compared with the second-visit group (97.9%, p = 0.001). Results of attempted correction within ±0.50 D were: 63.3% and 69.0%, respectively ( p = 0.009). Complications profiles in the two groups were comparable. Conclusions: Trans-PRK completed on the day of the first screening appointment demonstrated a similar safety outcome compared with subsequent-visits procedures, and slightly lower, yet comparable, results regarding efficacy and predictability.

scholarly journals Photorefractive keratectomy for correction of myopia: Our one-year experience

2012 ◽  
Vol 69 (10) ◽  
pp. 852-857
Author(s):  
Mirko Resan ◽  
Miroslav Vukosavljevic ◽  
Milorad Milivojevic
Keyword(s):  
Visual Acuity ◽  
Postoperative Complications ◽  
Intraoperative Complications ◽  
Mean Value ◽  
Ablation Depth ◽  
Laser In Situ Keratomileusis ◽  
Photorefractive Keratectomy ◽  
Corneal Tissue ◽  
Surgical Method ◽  
A Prospective Study

Background/Aim. Photorefractive keratectomy (PRK), after laser in situ keratomileusis (LASIK), is commonly performed refractive surgical method worldwide. The aim of this study was to examine the effectiveness and safety of PRK in correction of various strengths of myopia and to assess how much corneal tissue is being removed with one diopter sphere (Dsph) correction by using different optical zones (OZ). Methods. A prospective study with a follow-up period of 6 months included 55 patients of which 100 myopic eyes were treated by PRK method (one eye was included in 10 patients). Myopic eyes with a preoperative best corrected visual acuity (BCVA) = 1.0 (20/20) were analysed. In order to assess the effectiveness of PRK operated myopic eyes were divided into four groups according to the dioptric power: 1)? -1.75 Dsph (n = 26); 2) from -2 to -3.75 Dsph (n = 44); 3) from -4 to -6.75 Dsph (n = 23), and 4) ? -7 Dsph (n = 7). Myopic eyes with preoperative BCVA ? 0.9 (amblyopic eyes) were excluded from the study, as well as eyes with astigmatism > -1.5 Dcyl. To assess the effectiveness of PRK we examined the percentage of eyes in the mentioned groups, which derived uncorrected visual acuity (UCVA) 6 months after the intervention to the following: a) UCVA = 1.0 (20/20) and b) UCVA ? 0.5 (20/40). To assess the safety of PRK we examined the frequency of intraoperative and postoperative complications. To estimate how much corneal tissue was removed with one Dsph correction by using different OZ, we used preoperative and postoperative (after 6 months) central pachymetry values expressed in ?m and volume of cornea (central 7 mm) expressed in mm?. In that sense, we used only the myopic eyes with clear preoperative spherical refraction. The total number of these eyes was 27, of which 16 eyes were treated using a 6.5 mm OZ and 11 eyes using a 7 mm OZ. Results. Refractive spherical equivalent (RSE) for all eyes was in the range from -0.75 to -8.75 Dsph, and preoperative mean value of RSE with standard deviation (mean RSE ? SD) was -3.32 ? 1.83 Dsph. Six months after PRK, 91% of eyes had UCVA = 20/20, and 99% of eyes had UCVA ? 20/40. In the first group (? -1.75 Dsph) preoperative mean RSE ? SD was -1.34 ? 0.32 Dsph, six months after PRK, 96% of eyes had UCVA = 20/20, and 100% of eyes had UCVA ? 20/40. In the second group (from -2 to -3.75 Dsph) preoperative mean RSE ? SD was - 2.95 ? 0.57 Dsph, six months after PRK, 89% of eyes had UCVA = 20/20, and 100% of eyes had UCVA ? 20/40. In the third group (from -4 to -6.75 Dsph) preoperative mean RSE ? SD was - 4.93 ? 0.70 Dsph, six months after PRK, 100% of eyes had UCVA = 20/20. In the fourth group (? - 7 Dsph) preoperative mean RSE ? SD was -7.71 ? 0.67 Dsph, six months after PRK, 57% of eyes had UCVA = 20/20, and 86% of eyes had UCVA ? 20/40. There were no intraoperative complications while postoperative complications occurred in 2 patients - in both cases in one eye (2%). In that cases, epithelial defects were detected. In the group of eyes that were treated by 6.5 mm OZ mean RSE ? SD was -2.45 ? 0.99 Dsph, the ablation depth per 1 Dsph was 17.54 ? 5.58 ?m and ablated volume of central 7 mm cornea by 1 Dsph was 0.43 ? 0.18 mm?. In the group of eyes that were treated by 7 mm OZ mean RSE ? SD was -3.32 ? 2.26 Dsph, the ablation depth per 1 Dsph was 23.73 ? 6.91 ?m and ablated volume of central 7 mm cornea by 1 Dsph was 0.61 ? 0.31 mm?. Conclusion. PRK is effective and safe refractive surgical method for correcting myopia up to -8 .75 Dsph. OZ size is the main factor determining the depth of the excimer laser ablation of the corneal tissue volume consumed by 1 Dsph. Higher OZ value determines higher consumption of cornea tissue.

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