High-speed recording of thermal load during laser trans-epithelial corneal refractive surgery using a 750 Hz ablation system

Ortueta, Diego de; Arba-Mosquera, Samuel; Magnago, Thomas

doi:10.1016/j.optom.2018.05.002

Cited by 13 publications

(8 citation statements)

References 23 publications

(60 reference statements)

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“…The maximum ocular surface temperature during epithelial ablation ranges from 35.2°C to 39.7°C, and during high and low fluence laser stromal ablation ranges from 32.9°C to 36.5°C and from 34.4°C to 37.7°C, respectively. De Ortueta et al 21 concluded that limiting the maximum temperature to below the safety limit of 40°C reported in the literature could decrease the occurrence of postoperative corneal haze. The routine usage of chilled BSS before and immediately after laser ablation, and the time gap of about 10 s between PTK and PRK add a cooling effect to the cornea compensating for heat generated by the excimer laser.…”

Section: Discussionmentioning

confidence: 97%

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Single-Step Transepithelial Photorefractive Keratectomy in Low to Moderate Myopia: A One-Year Follow-Up Study

Abdelwahab¹,

Salem²,

Elfayoumi³

2021

OPTH

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Aim To evaluate predictability, safety, efficacy, and visual outcome of StreamLight. ™ (SL.), the newly released single-step transepithelial photorefractive keratectomy platform by Alcon WaveLight™ (WL). Methods In this prospective cohort study, photorefractive keratectomy (PRK) was conducted on 500 eyes of 250 patients seeking myopic refractive vision correction. The new single-step transepithelial PRK method was applied, using the SL. platform installed in the WL. Ex 500 excimer laser machine. Patients were followed up to monitor intensity and duration of postoperative pain, as well as speed of epithelial healing in the early post-operative period and visual acuity, postoperative refraction and development of postoperative haze for one year post-operatively. Results Average pain duration was 1.5 days, and the mean pain intensity score on a scale of 0–10 was 3.74 + 1.51. Mean postoperative spherical equivalence was 0.01 ± 0.38 D, and the final postoperative uncorrected distance visual acuity (UCDVA) was 20/20 in 98% of eyes included in this study. None of the eyes lost more than one Snellen chart line or developed visually significant postoperative haze during the follow-up period. Conclusion The new SL. platform for transepithelial PRK is a safe, accurate platform, offering an easier early post-operative recovery, with no compromise in final visual outcome.

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Section: Discussionmentioning

confidence: 97%

“…Transepithelial platforms result in less heat generation at the corneal surface. 21 Effective control of the maximum temperature rise during laser ablation could reduce the incidence of postoperative haze. The baseline ocular surface temperature, immediately prior to beginning excimer laser, ranges from 32°C to 34.9°C.…”

Section: Discussionmentioning

confidence: 99%

Single-Step Transepithelial Photorefractive Keratectomy in Low to Moderate Myopia: A One-Year Follow-Up Study

Abdelwahab¹,

Salem²,

Elfayoumi³

2021

OPTH

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“…This spatial and temporal separation of laser pulses minimises the thermal load by allowing time for localised cooling. When tested with the Amaris 750 Hz excimer laser during transPRK, De Ortueta found that this kept the corneal epithelium below the 40deg C safety net thought to be the level at which collagen proteins start to denature [ 47 , 48 ]. Incremental improvements to these treatment normograms have shown improved outcomes with respect to HOAs [ 49 ].…”

Section: Transprk Platformsmentioning

confidence: 99%

“…The incidence of thermally induced haze can be reduced with several methods, including the optimised ablation platforms that reduce the thermal load and leave behind a smoother stromal surface. Intraoperative routine usage of chilled balanced salt solutions and a time gap between epithelial and stromal ablation helps to limit the maximum temperature below the safe threshold of 40 °C, as recommended by De Ortueta [ 47 ], though this does increase the treatment time. Managing the thermal load will also decrease ocular surface pain after the procedure [ 110 ].…”

Section: Issuesmentioning

confidence: 99%

Transepithelial Photorefractive Keratectomy—Review

Way,

Elghobaier,

Nanavaty

2024

Vision

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The type and nature of refractive surgery procedures has greatly increased over the past few decades, allowing for almost all patient populations to be treated to extremely high satisfaction. Conventional photorefractive keratectomy involves the removal of the corneal epithelium through mechanical debridement or dilute alcohol instillation. An improvement to this method utilises laser epithelial removal in a single-step process termed transepithelial photorefractive keratectomy (transPRK). We explore the history of transPRK from its early adoption as a two-step process, identify different transPRK platforms from major manufacturers, and describe the role of transPRK in the refractive surgery armamentarium. This is a narrative review of the literature. This review finds that TransPRK is a safe and effective procedure that works across a variety of patient populations. Though often not seen as a primary treatment option when compared to other corneal-based procedures that offer a faster and more comfortable recovery, there are many scenarios in which these procedures are not possible. These include, but are not limited to, cases of corneal instability, previous refractive surgery, or transplant where higher-order aberrations can impair vision in a manner not amenable to spectacle or contact lens correction. We discuss refinements to the procedure that would help improve outcomes, including optimising patient discomfort after surgery as well as reducing corneal haze and refractive regression.

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“…Furthermore, the epithelial ablation rate is higher than that of the stroma. 2 As a result, performing trans-PRK to an abnormal epithelial surface could result in subsequent abnormal and unpredictable stromal ablation.…”

mentioning

confidence: 99%

Corneal Irregularity Induced by Transepithelial Photorefractive Keratectomy in a Patient With Partial Limbal Stem Cell Deficiency

Vakalopoulos,

Chatzea,

Chronopoulou

et al. 2023

Cornea

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Purpose: The aim of this study was to present a case of transepithelial photorefractive keratectomy (trans-PRK) laser ablation in a patient with partial limbal stem cell deficiency (LSCD) that resulted in corneal irregularity. Methods: A 23-year-old man with bilateral partial LSCD underwent trans-PRK for myopia correction 2 months before presentation to our department. Trans-PRK ablation was performed with a phototherapeutic keratectomy ablation profile set at 60 μm in the OD and 57 μm in the OS and 8 mm zone. At the time of presentation, the patient complained of decreased visual acuity. Corrected distant visual acuity was 20/20 (−3.25, −0.75 × 180 degrees) and 20/50 (−3.00, −3.00 × 180 degrees) in the OD and the OS, respectively. No further ocular history was reported other than prolonged soft contact lens use for myopia. Pre–trans-PRK tomography (WaveLight Oculyzer II diagnostic system, WaveLight GmbH, Germany) revealed bilateral superior steepening with corresponding epithelial thinning as obtained by the epithelial map using Optovue optical coherence tomography (Visionix Luneau technology). Slit-lamp examination showed bilateral superficial neovascularization, suggestive of early-stage LSCD. Results: A nonuniform laser stromal ablation resulting in corneal irregularity and decreased visual acuity was observed 2 months postoperatively. During the 6-month follow-up, corneal tomography was stable with only minimal improvement. At that time, corrected distant visual acuity remained 20/20 (−2.75, −0.75 × 160 degrees) in the OD and 20/50 (−3.00, −3.00 × 180 degrees) in the OS. Conclusions: Trans-PRK seems to be a contraindication in cases with corneal epithelial irregularities and could lead to abnormal and nonuniform stromal ablation.

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High-speed recording of thermal load during laser trans-epithelial corneal refractive surgery using a 750 Hz ablation system

Cited by 13 publications

References 23 publications

Single-Step Transepithelial Photorefractive Keratectomy in Low to Moderate Myopia: A One-Year Follow-Up Study

Single-Step Transepithelial Photorefractive Keratectomy in Low to Moderate Myopia: A One-Year Follow-Up Study

Transepithelial Photorefractive Keratectomy—Review

Corneal Irregularity Induced by Transepithelial Photorefractive Keratectomy in a Patient With Partial Limbal Stem Cell Deficiency

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