Alcohol-assisted Photorefractive Keratectomy Research Articles

Comparative study of transepithelial versus alcohol-assisted photorefractive keratectomy

Aim The aim of this study was to compare the clinical, refractive, and visual outcome of transepithelial photorefractive keratectomy (T-PRK) to the alcohol-assisted photorefractive keratectomy (AA-PRK). Patients and methods This is a prospective randomized controlled trial that included 60 myopic patients (120 eyes). They were randomized into two groups, 60 eyes each: group I (AA-PRK) and group II (T-PRK). The operation was performed in both groups by the same Excimer laser machine (EX 500 Excimer laser WaveLight). In the alcohol-assisted group, the corneal epithelium was removed by 20% ethyl alcohol followed by Excimer laser to correct the amount of ametropia. In the T-PRK group, the Streamlight PRK software (WaveLight EX 500) was used, which incorporated Excimer laser stromal ablation and epithelial removal in a single step. After completion of each procedure in both groups, mitomycin C with a concentration of 0.02% was used for 30 s, followed by copious irrigation with a cold balanced salt solution. A soft bandage contact lens was applied until epithelial healing was complete for 5 days and changed after 48 h. The patients were evaluated postoperatively on the first, third, and fifth day, then after 1 week, 1 month, and 3 months. On the first visit, uncorrected visual acuity (UCVA), epithelial healing, and postoperative pain were evaluated. At 1-week and 1-month follow-up visits, UCVA, best-corrected visual acuity (BCVA), manifest refraction spherical equivalent (MRSE), Schirmer’s I, and tear break-up time (TBUT) tests were evaluated. The corneal haze was evaluated using a slit lamp biomicroscope and subjectively graded. At the 3-month follow-up, UCVA, BCVA, MRSE, Schirmer’s I test, TBUT test, and root mean square (RMS) assessment for total higher-order aberration were evaluated. Results There was an insignificant difference between the studied groups regarding all baseline ophthalmological assessments including UCVA, BCVA, MRSE, central corneal thickness, RMS, TBUT, and Schirmer’s test (P=0.839, 0.057, 0.187, 0.537, 0.219, 0.013, and 0.151, respectively). After 3 months, the median UCVA was the same in both groups (1.0), while the MRSE did not differ significantly between the two groups (P=0.126), with a median (interquartile range) of −0.25 D (−0.75 to 0.25 D) in the AA-PRK group compared to −0.25 D (−0.50 to 0.3125 D) in the T-PRK group. The healing duration was significantly shorter in the T-PRK group (median=3.0 days) than in the AA-PRK group (5.0 days, P<0.001). The median postoperative pain was also significantly higher in the AA-PRK group (4.0) than in the T-PRK group (3.0, P<0.001). The RMS was significantly lower in the T-PRK group (median=0.35) than in the AA-PRK group (median=0.65, P<0.001). The corneal haze did not differ significantly between the two groups after 1 month (P=0.783). After 3 months, the Schirmer’s test was significantly lower in the AA-PRK group (median=18.0 mm) than in the T-PRK group (19.0 mm, P<0.001), while the TBUT test showed no significant difference (P=0.055). Conclusion The T-PRK technique provided a faster visual recovery with a better refractive outcome, faster healing response, less pain score, and less dryness than the AA-PRK.

Intraoperative variability of corneal epithelium thickness in photorefractive keratectomy

PurposeTo evaluate the intraoperative central corneal epithelial thickness (ET) as measured by optical coherence pachymetry (OCP) in myopic eyes undergoing alcohol-assisted photorefractive keratectomy (PRK).MethodsA retrospective review of patients who underwent alcohol-assisted PRK was performed. Data were abstracted on age, gender, contact lens (CL) wear, preoperative refractive errors, keratometry, topographic and ultrasonic pachymetry, and intraoperative OCP measurements before and after epithelium removal. The central ET was calculated by subtracting OCP measurement after epithelium removal from the OCP measurement prior to epithelium removal.ResultsThe study comprised of 162 consecutive eyes from 81 patients. Mean age was 26.73 ± 6.47 years, 50.6% were males. CL was used in 92 eyes (56.8%). The mean sphere and spherical equivalent were −3.60 ± 1.84 D and −3.26 ± 1.85D, respectively. The mean intraoperative ET was 58.22 ± 17.53 µm (range, 15–121µm). Fifty-five percent of the eyes had an ET measurement above or below the range of 40-60µm. ET was significantly higher in the second operated eye compared to the first operated eye (p = 0.006), and an association was found to CL-wear (p = 0.03). There was no significant difference in thickness between genders (p = 0.62), and no correlation to patient age (p = 0.45, rp = 0.06), refractive errors (p > 0.30,rp=−0.07–0.08), nor keratometry(p > 0.80, rp=−0.01− (−0.02)).ConclusionThe intraoperative assessment of ET in alcohol-assisted PRK showed a high variability of the central corneal epithelium, with a significant difference between the first and second operated eyes. This difference may have implications when the epithelium is not included in the surgical planning in surface ablation.

Does the introduction of streamlight decrease refractive surgery operating time?

The aim of the study was to analyze the time-savings associated with introduction of Streamlight™ (Alcon Laboratories, Fort Worth, TX, USA) transepithelial photorefractive keratectomy (PRK) in surface corneal ablations. All refractive surgeries were performed using the Alcon WaveLight® EX500 at the ArtLife Clinic, Gdańsk, Poland. The study included patients treated for refractive errors with transepithelial PRK between April 2019 and October 2021, who were matched with patients treated with alcohol-assisted PRK during the same period. Only results for the left eye were analyzed. One-hundred-five patients underwent transepithelial PRK (age 33.42 ± 8.67years) and were matched with 105 patients that underwent alcohol-assisted PRK (age 33.05 ± 10.16years; p = 0.11). The mean preoperative spherical equivalent refraction was - 2.04 ± 2.28 D, and - 1.9 ± 1.71 D for the transepithelial and alcohol-assisted PRK group, respectively (p = 0.20). The total surgery time was non-significantly shorter in transepithelial PRK (349.46 ± 47.83s) than in alcohol-assisted PRK (354.93 ± 137.63s; p = 0.7); however, the variance of surgical time was significantly lower in transepithelial PRK (p<0.001). The laser treatment duration was greater in transepithelial PRK (41.78 ± 17.2s) than in alcohol-assisted PRK (8.48 ± 6.12s; p < 0.001), and so was the number of breaks during the laser treatment (0.95 ± 0.63 vs. 0.53 ± 0.88, respectively; p < 0.001). The introduction of transepithelial PRK did not bring significant time-associated savings into the refractive surgery suite.

Comparison of Conventional Versus Trans-Epithelial Photorefractive Keratectomy in Hyperopia Treatment: A Contralateral Study

Background: This study was planned to compare Trans - epithelial Photorefractive Keratectomy (TPRK) and Alcohol Assisted Photorefractive Keratectomy (AAPRK) laser vision correction in hyperopia and compound hyperopic astigmatism.&#x0D; Methods: This quasi-experimental study was conducted on patients with hyperopia and hyperopic-astigmatism, whose eye laterality was randomly assigned to undergo TPRK versus AAPRK using SCHWIND AMARIS 1050RS (SCHWIND eye-tech-solutions, Germany). Follow up time was 1, 3, 6 and 12 months after surgery.&#x0D; Results: 112 eyes of 56 patients with mean age of 32.6 years included, of which 51.8% were female and 48.2% were male. Both TPRK and AAPRK methods were able to correct hyperopia and astigmatism safely and efficiently (p&lt;0.05 in all cases). Postoperative vision characteristics were similar in both methods (p=0.23 for sphere, p=0.52 for cylinder, p=0.064 for axis, and p=0.35 for BCVA) postoperatively. Corneal haze was observed in 44% of the patients with a direct strong correlation with hyperopia severity (r=0.607). Post-operative pain was observed in 60% of the patients with a direct weak correlation with hyperopia severity (r=0.27). Mild photophobia was seen in 42% of the patients with a direct weak correlation between photophobia and hyperopia severity (r=0.36). Epithelial healing time lasted an average of 3.48 days and there was a direct and moderate correlation with hyperopia severity (r=0.4). Safety index in TPRK and AAPRK was 0.54 and 0.45, respectively, with no significant difference (p=0.42); Efficacy index was 0.96 and 0.9 in TPRK and AAPRK, respectively and there was no significant difference between two groups (p=0.23). No complication was observed in all of the patients.&#x0D; Conclusion: TPRK and AAPRK laser vision correction are both safe and efficient in hyperopia and compound hyperopic astigmatism. There is no significant difference regarding epithelial healing time, post-operative pain and haze formation between two procedures.

Long-term results of hyperopic ablations using alcohol-assisted PRK and FS-LASIK: comparative study.

To evaluate the long-term visual and refractive outcomes of hyperopic excimer ablation using alcohol-assisted photorefractive keratectomy (PRK) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK). American University of Beirut Medical Center, Beirut, Lebanon. Retrospective, matched comparative study. Eyes that underwent alcohol-assisted PRK were compared to matched eyes that underwent FS-LASIK. All patients were followed up for at least 3 years after surgery. The refractive and visual outcomes of each group were compared at different postoperative time points. The main outcome measures were spherical equivalent deviation from target (SEDT), manifest refraction, and visual acuity. 83 eyes underwent alcohol-assisted PRK and 83 matched eyes underwent FS-LASIK. Preoperative manifest refraction spherical equivalent was 2.44 ± 1.18 diopters (D) and 2.20 ± 0.87 D ( P = .133) in the PRK and FS-LASIK groups, respectively. Preoperative manifest cylinder was -0.77 ± 0.89 D and -0.61 ± 0.59 D ( P = .175) for the PRK and LASIK groups, respectively. 3 years postoperatively, SEDT was 0.28 ± 0.66 D and 0.40 ± 0.56 D for the PRK and LASIK groups, respectively ( P = .222), whereas manifest cylinder was -0.55 ± 0.49 D and -0.30 ± 0.34 D for PRK and LASIK, respectively ( P < .001). The mean difference vector was 0.59 ± 0.46 for PRK and 0.38 ± 0.32 for LASIK ( P < .001). 13.3% of PRK eyes and 0% of LASIK eyes had >1 D of manifest cylinder ( P = .003). Both alcohol-assisted PRK and FS-LASIK are safe and effective for the treatment of hyperopia. PRK induces slightly more postoperative astigmatism than LASIK. Larger optical zones and recently introduced ablation profiles that lead to a smoother ablation surface might improve the clinical results of hyperopic PRK.

Outcomes of Single-Step Transepithelial Photorefractive Keratectomy Compared With Alcohol-Assisted Photorefractive Keratectomy Using Wave-Light EX500 Platform.

Purpose To compare the visual outcome of transepithelial photorefractive keratectomy (PRK) against alcohol-assisted PRK in treating low-to-moderate myopia with or without astigmatism. Setting Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia. Design This is a retrospective study. Methods Forty eyes of 22 patients with myopia from -0.75 to -6.00 diopters (D) with or without astigmatism from 0 to -3D were included in this study. Preoperative and postoperative data of 20 eyes from 11 patients who underwent transepithelial PRK were compared with 20 eyes from 11 patients who underwent alcohol-assisted PRK were collected and analyzed. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest spherical equivalence (SE), manifest cylinder, vector analysis of astigmatism, and efficacy and safety indices were compared between the groups at a mean follow-up of one year postoperatively. Results Baseline characteristics were similar between groups, except the transepithelial PRK group had lower cylinder values than the alcohol-assisted PRK group by 0.69D. Regression analysis was used to control for the difference in the cylinder in all outcome parameters. Both groups had similar mean UDVA (p=0.73), CDVA (p=0.98), the proportion of eyes in either group achieved (20/20, 20/25, and 20/30) UDVA (p=0.72, 0.68 and 0.31 respectively) and percentage of eyes lost two lines of CDVA (p=1.0). There was no statistically significant difference between the two groups in regard to both efficacy and safety indices (p=0.55 and 0.67, respectively). Both groups had similar residual SE (p=0.72), the proportion of eyes within ±0.5D of SE (p=0.29), and residual refractive astigmatism (p=0.87). Both groups had similar difference vectors, surgically induced astigmatism, and correction index (p=0.82, 0.10, and 0.26, respectively). However, the transepithelial PRK group had lower target-induced astigmatism (TIA; p=0.01), higher magnitude of error (ME; p=0.05), and higher angle of error (AE; p=0.02) than the alcohol-assisted PRK group. Conclusion Transepithelial PRK had similar visual and refractive outcomes as alcohol-assisted PRK. This approach was considered as safe and effective as alcohol-assisted PRK in treating patients with low-to-moderate myopia with or without astigmatism.

Twelve-month outcomes of single-step transepithelial photorefractive keratectomy for moderate hyperopia and hyperopic astigmatism

BackgroundConventional mechanical or alcohol-assisted photorefractive keratectomy (PRK) techniques for correction of hyperopia and hyperopic astigmatism were associated with inconsistent results. The aim of this study is to evaluate the 12-month visual and refractive outcomes of the relatively new single-step transepithelial photorefractive keratectomy (TE-PRK) for moderate hyperopia and hyperopic astigmatism. MethodsThis is a prospective interventional study. Forty-eight eyes of 30 patients with moderate hyperopia or hyperopic astigmatism with a cycloplegic spherical equivalent refraction (SEQ) between 2.0 and 4.5 diopters (D) underwent single-step StreamLight® TE-PRK using EX500 excimer laser (Alcon Laboratories, USA). The main outcome measures were recorded at 6 and 12 months postoperatively including assessment of logarithm of the minimum angle resolution (logMAR) uncorrected and corrected distance visual acuity (UDVA, CDVA), cycloplegic refraction, corneal topographic changes as well as post-PRK peripheral haze grading.ResultsThe mean preoperative cycloplegic SEQ was significantly reduced from 3.21 ± 0.61 D to 0.35 ± 0.04 D and 0.41 ± 0.04 D at 6 and 12 months, respectively (P < 0.001). The mean preoperative UDVA significantly improved from 0.53 ± 0.02 logMAR to 0.07 ± 0.01 logMAR and 0.08 ± 0.01 logMAR at 6 and 12 months, respectively (P < 0.001) while the mean preoperative logMAR CDVA showed non-significant change over time throughout the study (P = 0.135). At the end of the study, 41 eyes (85.4%) achieved UDVA of 20/25 or better and no eye lost any lines of CDVA. Thirty-eight eyes (79.1%) had a postoperative cycloplegic cylinder of 0.5 D or less at 12 months. The mean preoperative mean keratometry showed significant increase at 6 and 12 months postoperatively (P < 0.001) while there was no significant change between the two postoperative visits denoting topographic stability (P = 0.058). The mean postoperative Q value at 6 and 12 months showed a significant prolate shift (P < 0.001). No haze was observed in 62.5% and 85.4% of the enrolled eyes at 6 and 12 months, respectively.ConclusionsSingle-step StreamLight® TE-PRK for moderate hyperopia and hyperopic astigmatism achieved acceptable visual and refractive outcomes.Trial registration: (Clinicaltrials.gov): NCT05261685, 2 March 2022, retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05261685

Comparison of objective and subjective visual quality after flapless laser vision correction for mild to moderate myopia: SMILE vs PRK.

To investigate the differences in surgical results and the objective and subjective quality of vision (QoV) of patients after small incision lenticule extraction (SMILE) versus alcohol-assisted photorefractive keratectomy (PRK). Medical records of patients treated with SMILE and PRK were retrospectively examined. Visual quality, biometric parameters, Strehl ratio (SR), and corneal higher-order aberrations (HOAs) within a 6.0mm area were recorded. The effective optical zone (EOZ) and decentration were measured using a tangential pre-post operation difference map. Subjective QoV and operation satisfaction were evaluated 6months postoperatively using the Quality of Vision questionnaire. The study comprised 100 eyes treated with SMILE (preoperative mean spherical equivalent (SE), - 4.52 ± 0.81 dioptres (D)) and 69 eyes with PRK (mean SE, - 4.21 ± 1.25 D). Six months postoperatively, the EOZ reduction was significantly larger in the PRK group (P < 0.001). Decentrations were comparable between the groups. Regarding visual symptoms, monocular diplopia was more common following PRK (P = 0.02), and 98 (98.00%) SMILE-treated and 67 (97.10%) PRK-treated patients were satisfied with the QoV. Both groups demonstrated significant increases in total HOAs, coma, and spherical aberration (SA) at 6months postoperatively compared to preoperatively (P < 0.001); these values were significantly higher in the PRK (P < 0.05) compared to the SMILE group. SR increased significantly only in the PRK group (P < 0.05). Although EOZ was more consistent with anticipated treatment and HOAs were fewer in SMILE, high patient-reported satisfaction and good corneal optical quality were achieved in both groups, indicating that both SMILE and alcohol-assisted PRK are excellent options for mild to moderate myopia correction.

Surface Refractive Surgery Outcomes in Israeli Combat Pilots

Photorefractive keratectomy (PRK) has long been the method of choice for refractive surgery in pilots, and was FDA approved for U.S. Air Force aviators in 2000. We retrospectively reviewed the medical records of 16 male combat pilots (mean age 25.0 ± 5.5 years) who had undergone bilateral laser refractive surgery with surface ablation (alcohol-assisted PRK: 81.25%, transepithelial-PRK: 18.75%), and who had a mean baseline spherical equivalent (SE) of −2.1 ± 0.7 D in the right eye, and −2.0 ± 0.7 D in the left. The mean follow-up was 8.4 ± 6.6 months. On the last visit, the uncorrected visual acuity (UCVA) had improved from 0.75 ± 0.33 logMar to −0.02 ± 0.03 logMar (p &lt; 0.001), and from 0.72 ± 0.36 logMar to −0.02 ± 0.05 logMar (p &lt; 0.001), for the right and left eyes, respectively. The percentages of participants with a right eye UCVA of at least 0.0, −0.08, and −0.18 logMAR (6/6, 6/5, and 6/4 Snellen in meters) were 100%, 37.5%, and 6.2%, respectively, and for the left eye, 93.7%, 43.75%, and 6.2%, respectively. No complications occurred. This is the first study to assess refractive surgery outcomes in a cohort of Israeli combat pilots. Surface refractive surgery effectively improved UCVA and reduced spectacle reliance for the members of this visually demanding profession.

Photorefractive Keratectomy Enhancement (PRK) After Small-Incision Lenticule Extraction (SMILE).

PurposeTo determine rates of enhancement and visual prognosis following photorefractive keratectomy (PRK) enhancement of small-incision lenticule extraction (SMILE).Patients and MethodsThis retrospective, single-site study reviewed all cases of primary SMILE at Hoopes Vision in Draper, Utah between March 14, 2017 and April 8, 2022 to identify any cases that required follow-up enhancement. Primary SMILE was performed using Visumax 500 kHz femtosecond laser (Carl Zeiss Meditec, Jena, Germany). All enhancements were performed with alcohol-assisted PRK, using a WaveLight EX500 excimer laser (Alcon Laboratories, Inc., Fort Worth, TX).ResultsFour hundred and five eyes underwent primary SMILE, of which 15 later underwent PRK enhancement (enhancement rate of 3.7%). No significant difference in pre-SMILE data was identified between the enhancement and non-enhancement groups. The average age of those who underwent PRK enhancement was 33.8±6.3 years old and ranged from 25 to 45. Following primary SMILE, 13 eyes (87%) had an uncorrected distance visual acuity (UDVA) of 20/40 or better, and none had a UDVA of 20/20 or better. After one year of post-enhancement follow-up, all eyes had a UDVA of 20/40 or better, and 13 eyes (87%) had a UDVA of 20/20 or better (Figure 1). All were within one diopter of target spherical equivalent (SEQ), 13 (87%) were within 0.50 D, and 10 (67%) were within 0.25 D. Of those with 12-month follow-up data, none had UDVA worse than corrected distance visual acuity (CDVA), and none had lost lines of CDVA. Efficacy and safety indices were 1.03 and 0.99, respectively.ConclusionFollowing SMILE, ophthalmologists may anticipate an enhancement rate of one to seven percent. In these cases, PRK is a safe and effective procedure for enhancement of SMILE.

Surface ablation outcomes in high myopia with different epithelium removal techniques

To study the outcomes of alcohol-assisted photorefractive keratectomy (PRK) when compared with transepithelial PRK (TransPRK) using 2 software programs, with or without SmartPulse Technology (SmartSurfACE), in high myopia. Vissum Miranza, University Miguel Hernandez, Alicante, Spain. Retrospective, consecutive, case series. High myopic eyes undergoing surface ablation were included. The main inclusion criteria were preoperative spherical equivalent (SE) above -5.50 diopters (D) and no other ocular surgeries. Mitomycin-C was used in all the surgeries. The outcomes were analyzed using the 6-month follow-up visit data. 135 eyes were included. Alcohol-assisted PRK was performed in 65 eyes, transepithelial PRK (TransPRK1) in 32 eyes, and TransPRK2 in 38 eyes. The mean all groups preoperative sphere, cylinder, and SE were -6.00 ± 0.87 D, -1.13 ± 1.03 D, and -6.57 ± 0.69 D, respectively. The mean efficacy index in the alcohol-assisted PRK group was 0.91 ± 0.18 compared with 0.98 ± 0.1 and 0.98 ± 0.12 in the TransPRK1 and TransPRK2, respectively (P = .027). The mean safety index in alcohol-assisted PRK was 0.99 ± 0.05, whereas it was 1 ± 0.06 in the TransPRK1 and 0.99 ± 0.08 in the TransPRK2 (P = .780). A final SE of ± 0.50 D was achieved in 96.9% of eyes in the TransPRK1 group and in 100% eyes in the TransPRK2 group compared with 73.8% in the alcohol-assisted PRK group (P < .001). Surface ablation with the Amaris 500 excimer laser with flying spot pattern and mitomycin C use showed adequate refractive outcomes in high myopia correction in the 3 groups. TransPRK with or without SmartPulse Technology achieved statistically significant better outcomes than alcohol-assisted PRK in refractive predictability and efficacy.

Reliability and Validity of the Persian Version of Quality of Life Impact of Refractive Correction Questionnaire.

Purpose:To evaluate the psychometric properties of the Persian version of quality of life impact of refractive correction (QIRC) questionnaire and its utility in assessment of refractive error-related quality of life (QoL) following photorefractive keratectomy (PRK).Methods:Patients with low-to-moderate myopia (−0.75 to − 6.0) were enrolled in this study. Standard alcohol-assisted PRK was performed in all patients. The QIRC questionnaire was translated into a Persian version using the standard method. Patients completed QIRC questionnaire preoperatively and 3-month postoperatively. A group of patients completed the questionnaire twice preoperatively. Psychometric properties were evaluated by internal consistency (Cronbach's α), item-total correlation, and known group construct validity. Intraclass correlation coefficient (ICC) were used to examine the repeatability.Results:One hundred forty-seven patients (60 males and 87 females) with a mean age of 26.3 ± 5.5 (range, 18–39) years were enrolled. Cronbach's α for total score was 0.923. Item-total correlation was above 0.3 for all items. ICC was 0.978 for total score. Preoperatively, predominantly contact lens wearers showed significantly better total QIRC score than predominantly spectacle wearers (P = 0.017), which showed good known group validity. Total QIRC score significantly increased from 41.31 ± 6.69 preoperatively to 50.47 ± 7.26 postoperatively (P < 0.0001). Improvement in total QIRC score was observed both in contact lens wearers and spectacle wearers.Conclusion:The Persian version of QIRC questionnaire is a valid and reliable tool. Refractive error-related QoL assess by QIRC was significantly improved after PRK in an Iranian population.

Epi-Bowman keratectomy versus alcohol-assisted photorefractive keratectomy: wound healing and complications

Purpose:In Epi-Bowman Keratectomy™ (EBK), a new dynamic multi-blade single-use device (Epi-Clear™, Orca Surgical, Israel) is utilized to remove the epithelium by sweeping movements across the corneal surface. Epithelial cells are discarded. Alcohol or other chemical agents are not utilized. We wanted to compare clinical results of Epi-Clear photorefractive kertectomy (PRK) to alcohol-assisted PRK.Study design:Retrospective, comparative study.Methods:Consecutive case series: Adult patients seeking laser vision correction of myopia or myopic astigmatism without ocular diseases or prior surgery were included. The Epi-Clear PRK group comprised 50 consecutive eyes of 27 patients and the PRK group 50 eyes of 25 patients.Results:No intraoperative complications occurred. Epi-Clear PRK: At day 1, day 4, and 3 months, uncorrected distance visual acuity (UDVA) was 0.41/0.47/0.93 (decimal scale); epithelial defect diameter was 4.7/0.2/0 (mm); pain level was 3.8/0.3/0 (visual analogue scale, 0–10), respectively. At 3 months, efficacy index was 0.86 and spherical aberrations were unchanged. Three eyes (6%) showed (presumably sterile) infiltrates. PRK: At day 1, day 4, and 3 months, UDVA was 0.56/0.46/1.15; epithelial defect diameter was 6.3/0.2/0 (mm); pain level was 5.0/0.3/0, respectively. At 3 months, efficacy index was 1.1 and spherical aberrations were unchanged.Conclusion:The new method of epithelial debridement with Epi-Clear before laser ablation seems to offer fast epithelial removal without nicking Bowman’s layer (as observed with the laser microscope). However, we found significantly inferior results of Epi-Clear PRK compared to alcohol-assisted PRK. Furthermore, after Epi-Clear PRK corneal infiltrates as a new type of postoperative complication were observed.

Comparison between Transepithelial Photorefractive Keratectomy versus Alcohol-Assisted Photorefractive Keratectomy in Correction of Myopia and Myopic Astigmatism.

Purpose The aim of the study was to compare visual acuity, refractive results, safety, and efficacy of TPRK with AAPRK as primary outcomes and surgical time, pain scores, haze levels, and healing time as secondary outcomes in TPRK and AAPRK groups. Setting Security Forces Hospital, Ophthalmology Department, Riyadh, Kingdom of Saudi Arabia. Design Prospective, nonrandomized case-control comparative study. Methods A total of 200 eyes of 100 consecutive patients were included. One hundred eyes underwent TPRK in the right eye (study group), and 100 eyes underwent AAPRK in the left eye (control group). Ablations were performed with the Schwind Amaris excimer LASER750S. Clinical outcomes during 6 months' follow-up were compared. Results The mean age of patients was 28.3 ± 6.3, 77 were females and 23 males. The mean surgical time was 162.17 ± 14.827 s and 243.24 ± 98.69 s, respectively. At day 1, the UDVA mean was 0.7 in 87% of eyes in the TPRK group while it was 0.5 in 45% of eyes in AAPRK; at week 1, it was 0.9 in 88% of eyes in the TPRK group and 0.6 in 60% of eyes in AAPRK. The mean pain scores were less and lower incidence of corneal haze in the TPRK. Complete epithelial healing time was shorter in TPRK, 3.20 ± 0.686 and 4.60 ± 1.969 days, respectively. Conclusions TPRK and AAPRK produce similar results 6 months postoperatively. However, in the early postoperative period, there were significant differences in UDVA, pain score, level of haze, and complete epithelial healing time. The pain scores were lower, level of haze was less, and healing time was shorter in the TPRK group which provided patient better felling and comfort in this period. Both of procedures are effective and safe for correction of myopia and compound myopic astigmatism. This trial is registered with NCT03569423.

Influence of a Therapeutic Soft Contact Lens on Epithelial Healing, Visual Recovery, Haze, and Pain After Photorefractive Keratectomy.

To examine the influence of a therapeutic soft contact lens (TSCL) after alcohol-assisted photorefractive keratectomy (PRK) on visual recovery, epithelial closure, pain perception, and haze formation. Prospective, randomized, single-center, contralateral eye, patient-masked study. Same surgeon treated 15 patients with bilateral PRK using a Vidaurri Fluid Retention Ring (Katena) with 8.7 mm inner diameter to apply ethanol 18% for 30 sec. Each patient received a TSCL (Balafilcon A, PureVision, Bausch & Lomb) in a randomized fashion in one eye only. Without knowing which eye had a contact lens, four patients preferred the eye with TSCL so much that these patients wanted a TSCL inserted in the second eye as well. Uncorrected distance visual acuity improved postoperatively from day 1 to 3 months from 0.61 to 1.18 with TSCL and from 0.21 to 1.04 without TSCL. Uncorrected distance visual acuity was statistically significantly better on days 1 and 2 with TSCL. Epithelial defect was on average smaller with TSCL. Epithelium was closed at day 4 in all eyes except one without TSCL. Pain perception was significantly lower with TSCL on days 1 and 2. Haze levels after 3 months were significantly lower with TSCL (with 0.09/without 0.45, respectively). One eye without TSCL had haze grade 2 (Fantes). A TSCL had statistically significantly and clinically meaningful beneficial effects in the first days in visual recovery and pain perception and after 3 months in haze formation. Epithelial healing was slightly quicker with the use of TSCLs (not statistically, but clinically significantly).

Three-year outcomes after high hyperopia correction using photorefractive keratectomy with a large ablation zone

AimTo evaluate refractive and visual outcomes of photorefractive keratectomy (PRK) to treat high hyperopia using an aberration-neutral profile and large ablation zone.MethodsThis was a retrospective, consecutive observational case series at...

Safety and complications after three different surface ablation techniques with mitomycin C: a retrospective analysis of 2757 eyes.

To evaluate the safety and spectrum of complications of three excimer laser surface ablation techniques (SATs) with an intraoperative application of mitomycin C (MMC) 0.02%. A retrospective, non-comparative large case series. SATs were performed on 2757 eyes with a preoperative spherical equivalent (SE) of - 4.41 ± 2.44 and a Wavelight Allegretto 200 platform. Ablation zone diameters between 6.0 and 7.0mm were used according to mesopic pupil size. All patients were treated with an intraoperative application of MMC for 30 to 90s depending on refractive error. The mean follow-up time was > 3months (107 ± 24days). Complication range and incidence were analyzed retrospectively and safety index was calculated. Two thousand seven hundred and fifty-seven eyes met the inclusion criteria for surface ablation. Two thousand five hundred and seventy-three eyes were assigned to alcohol-assisted photorefractive keratectomy (APRK), 135 eyes to transepithelial photorefractive keratectomy (TPRK), and 49 eyes to off-flap epithelial laser in situ keratomileusis (EpiLASIK/EpiK). Overall, the safety index was 1.06 ± 0.28. Haze was graded according to the Fantes scale. Haze incidence rates were highest in the TPRK group (14.81%) and comparably low in APRK (2.95%) and EpiK (4.08%) groups. Intraoperative topical application of MMC (0.02%) results in good safety and no severe side effects. However, highest incidence of haze was observed after TPRK. The more frequent peripheral localization of haze might be attributed to large ablation zones and the wavefront optimized ablation profile especially in the PTK modus of the laser platform.

Epithelial Erosions and Refractive Results After Single-Step Transepithelial Photorefractive Keratectomy and Alcohol-Assisted Photorefractive Keratectomy in Myopic Eyes: A Comparative Evaluation Over 12 Months

To evaluate the epithelial erosion incidence and refractive results in myopic eyes undergoing single-step transepithelial photorefractive keratectomy (TransPRK) compared with alcohol-assisted photorefractive keratectomy (PRK). This was a retrospective nonrandomized comparative study conducted at the American University of Beirut Medical Center. A total of 189 eyes that had undergone single-step transepithelial PRK (TransPRK) were compared with 189 matched eyes that had undergone alcohol-assisted PRK over a follow-up of 1 year. The incidence and symptoms of epithelial erosion were evaluated in both treatment groups using a post hoc questionnaire administered to patients selected in the study. Visual and refractive outcomes, including vector analysis of astigmatism, and corneal higher-order aberrations were also compared at 1-year postoperatively. Baseline characteristics were similar between 2 groups (P > 0.05). A slight difference was detected at 12-month follow-up in the refractive cylinder (P = 0.02) and difference vector (P = 0.01) between eyes that had undergone TransPRK versus alcohol-assisted PRK. All other visual and refractive outcomes were similar at 12-month follow-up between both groups. Of note, 9.9% of patients with alcohol-assisted PRK (10/101) reported to the clinic because of tearing and stabbing sensation within 1 week after contact lens removal as opposed to 1% (1/100) of the TransPRK group (P = 0.0097). Subclinical recurrent epithelial erosion symptoms occurred more frequently in alcohol-assisted PRK: soreness to touch, sharp pains, and eyelid sticking occurred in 26.0% versus 6.6%, 32.5% versus 7.9%, and 26.0% versus 6.6% among the patients who were treated with alcohol-assisted PRK versus those who were treated with TransPRK, respectively (P ≤ 0.002). Single-step TransPRK for myopic eyes yields refractive results similar to those of alcohol-assisted PRK but shows a lesser incidence of early postoperative epithelial erosions and subsequent subclinical recurrent erosions.

Enhancement after Small-Incision Lenticule Extraction: Incidence, Risk Factors, and Outcomes

To report the incidence, risk factors, and outcomes of enhancement after small-incision lenticule extraction (SMILE). Retrospective cohort study. Five hundred twenty-four eyes of 307 patients who underwent SMILE at Singapore National Eye Center between February 2012 and March2016. The data collected included patient age at primary SMILE, gender, race, preoperative and postoperative manifest refraction spherical equivalent (MRSE), preoperative and postoperative uncorrected distance visual acuity and corrected distance visual acuity, the occurrence of suction loss during the procedure, and the need for enhancement. All enhancements were carried out by performing an alcohol-assisted photorefractive keratectomy (PRK) procedure with application of mitomycin C (MMC). Incidence, prevalence, preoperative and intraoperative risk factors for enhancement, and outcomes after enhancement. The prevalence of enhancement was 2.7%, and 71.4% eyes had enhancement within 1 year of primary SMILE. The incidence of enhancement was 2.1% and 2.9% at 1 and 2 years, respectively. Age older than 35 years, preoperative MRSE more than-6.00 diopters (D), preoperative myopia more than 6.00 D, preoperative astigmatism more than 3.00 D, and intraoperative suction loss were significant risk factors for enhancement after SMILE after adjusting for all other covariates (odds ratios, 5.58, 4.80, 1.41, 3.06, and 2.14, respectively; P= 0.004, 0.021, 0.022, 0.002, and 0.020, respectively). In the patients who underwent bilateral SMILE, the first-operated eye had a marginal trend toward significance for enhancement (P= 0.054). There was no gender or racial difference. In the 14 eyes requiring enhancement, the uncorrected distance visual acuity before enhancement ranged from 20/80 to 20/25, and the mean attempted enhancement spherical equivalent was-0.50±0.86 D. The uncorrected distance visual acuity improved in most patients (92.9%) after enhancement. The 2-year incidence of enhancement after SMILE was 2.9%. Risk factors associated with enhancement included older age at SMILE procedure, greater preoperative MRSE, greater preoperative myopia, greater preoperative astigmatism, and the occurrence of intraoperative suction loss. Clinical outcomes of using PRK with application of MMC for enhancement were good.

Single-step transepithelial versus alcohol-assisted photorefractive keratectomy in the treatment of high myopia: a comparative evaluation over 12 months

Background/aimsTo evaluate refractive outcomes of single-step transepithelial photorefractive keratectomy (TransPRK) versus alcohol-assisted PRK (EtOH-PRK) for the correction of high myopia.MethodsThis was a retrospective non-randomised comparative study conducted at the American...