Laser Epithelial Keratomileusis Group Research Articles

Comparison of Corneal Densitometry and Visual Quality after Small Incision Lenticule Extraction (SMILE) and Laser Epithelial Keratomileusis (LASEK): One-Year Comparative Study.

To investigate changes in corneal densitometry (CD) and visual quality following small incision lenticule extraction (SMILE) and laser epithelial keratomileusis (LASEK) in patients with mild-to-moderate myopia. A retrospective analysis was performed on 24 and 25 patients (46 eyes each) who underwent SMILE and LASEK, respectively, for mild-to-moderate myopia. The visual quality and CD values were recorded. Using the Pentacam Scheimpflug system, CD values were collected in three concentric optical zones at the depths of the anterior, central, and posterior layers. Efficacy, safety, predictability, corneal wavefront aberrations, and QoV scores were measured to evaluate visual quality. A correlation analysis was performed between changes in CD and clinical characteristics. There were no statistical differences in efficacy and safety indices between the two groups. At 3 months postoperatively, a pronounced reduction in several zones was observed in the LASEK group (p < 0.05), whereas no obvious change was observed in the SMILE group. There were obvious changes in the CD values in several zones in the SMILE and LASEK groups (p < 0.05) after 1 year. The magnitude of the CD changes in the anterior and central corneal layers was smaller in the SMILE group than in the LASEK group (all p < 0.05). Lower HOAs, spherical aberration, and horizontal comas of the anterior and whole corneal surfaces were observed in the SMILE group. QoV scores were similar between the two groups. CD decreased in the SMILE and LASEK groups after 1 year; there was a smaller reduction in SMILE than in LASEK. SMILE and LASEK did not differ significantly in terms of safety and effectiveness in correcting mild-to-moderate myopia.

Comparison of Visual Quality with Ocular Higher-Order Aberrations in Laser Epithelial Keratomileusis and Soft Contact Lens Wear

Purpose : To compare visual quality with ocular higher-order aberrations (HOA) in laser epithelial keratomileusis (LASEK) and soft contact lens wear for myopia. Methods : Eighty eyes of 40 subjects who had undergone LASEK, 40 eyes of 20 subjects who have successfully fitted soft contact lenses and 38 eyes of 19 emmetropes were enrolled. The subjects’ criteria were best unaided monocular visual acuity of 20/20 or better. High and low contrast visual acuities (HCVA and LCVA) test, and contrast sensitivity test were measured under photopic and mesopic conditions. Ocular HOAs were measured using Wavefront Analyzer (KR-1W, Topcon) for 4 mm and 6 mm pupils. Results : HCVA and LCVA under photopic conditions were not statistically different between LASEK and contact lens wear groups compared with an emmetropic group. However, HCVA and LCVA under mesopic conditions were statistically different among the three groups (HCVA; p=0.031, LCVA; p=0.025, respectively). There were statistically significant differences in contrast sensitivity at 6, 12, and 18 cpd both under photopic and mesopic conditions between LASEK and contact lens wear groups (6cpd; p=0.000, 12cpd; p=0.000, 18cpd; p=0.000, redpectively). There were significant differences in ocular HOAs for both 4 mm and 6 mm pupils between LASEK and contact lens wear groups (total HOAs; p=0.000, coma; p=0.000, spherical aberration; p=0.000). Conclusion : LASEK, soft contact lens wear and emmetropic groups could not affect the quality of vision under photopic conditions. Nevertheless, the higher pupil size in the LASEK, the larger the amount of HOAs, the more likely it would have an influence on the visual quality during the night.

Clinical outcomes after laser epithelial keratomileusis (LASEK) and transepithelial photorefractive keratectomy (TPRK) in myopia

Objective: To compare the clinical outcomes between laser epithelial keratomileusis (LASEK) and transepithelial photorefractive keratectomy (TPRK) for treatment of myopia. Methods: Case-control study. We reviewed a total of 90 right eyes that underwent either LASEK or TPRK, with 45 eyes in each group (aged between 18 and 40 years; 9 males and 16 females in the LASEK group, and 30 males and 15 females in the TPRK group) from 2015 to 2016 in Peking Union Medical College Hospital and Tangshan Eye Hospital. All the patients were followed up for 6 months postoperatively. Pain, uncorrected visual acuity (UCVA), and haze were measured at postoperative 3 days, 7 days, 1 month, 3 months and 6 months, and compared using an independent Student t-test between the two groups. Degree of haze, eye pain score, and visual acuity were compared by the Mann-Whitney U test. Results: At 3 days, the pain score was 1 (0,3) in the LASEK group versus 0 (0,1) in the TPRK group (Z=5.643, P=0.001). The UCVA was 4.80±0.10 in the LASEK group versus 4.97±0.07 in the TPRK group (Z=6.930, P=0.000) at 3 days, 4.98±0.08 in the LASEK group versus 5.05±0.06 in the TPRK group (Z=8.147, P=0.000) at 7 days, and 5.02±0.05 in the LASEK group versus 5.06±0.06 in the TPRK group (Z=2.381, P=0.017) at 1 month. The UCVA was also measured at 3 months, 5.07±0.07 versus 5.10±0.07 (Z=1.632, P=0.103), and at 6 months, 5.10±0.07 versus 5.11±0.07 (Z=0.798, P=0.425), respectively, with no statistical significance. The residual diopter was (0.17±0.19) D in the LASEK group versus (0.17±0.20) D in the TPRK group (Z=0.097, P=0.923) at 1 month, (0.03±0.11) D versus (0.07±0.14) D (Z=0.166, P=0.096) at 3 months, (0.07±0.13) D versus (0.07±0.14) D (Z=0.002, P=0.978) at 6 months, respectively. The surface regularity index (SRI) was 0.48±0.09 in the LASEK group and 0.46±0.06 in the TPRK group (t=0.88, P=0.37) at 1 month, and 0.49±0.07 in the LASEK group versus 0.47±0.06 in the TPRK group (t=1.53, P=0.132) at 3 months. Transient haze was documented in 1 eye in each group at 1 month (4.4%), with a maximum index of 0.5. No haze was observed in either group at 6 months. Conclusion: TPRK has the advantages of faster early vision recovery and significantly less pain over LASEK. (Chin J Ophthalmol, 2019, 55: 122-126).

Laser-assisted subepithelial keratectomy (LASEK) versus photorefractive keratectomy (PRK) for correction of myopia.

Laser-assisted subepithelial keratectomy (LASEK) versus photorefractive keratectomy (PRK) for correction of myopia.

Long term results of no-alcohol laser epithelial keratomileusis and photorefractive keratectomy for myopia.

To evaluate the long term clinical results of mechanical no-alcohol-assisted laser epithelial keratomileusis (LASEK) versus standard photorefractive keratectomy (PRK) for low-moderate myopia. Twenty-five eyes treated with LASEK and twenty-five eyes treated with PRK were evaluated with a mean follow-up duration of 60mo. Mechanical separation of the epithelium was performed with blunt spatula and without application of alcohol. Laser ablation was performed with the MEL-70 excimer laser. All patients were examined daily until epithelial closure; at 1, 3, 6, and 12mo, and every year subsequently. Main outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, haze, efficacy and safety indexes. Twenty-one eyes and 22 eyes completed follow-up of 60mo in LASEK and PRK group respectively. Manifest refraction at 60mo follow-up was -0.01 and 0.26 in LASEK and PRK group respectively. In the LASEK group mean UDVA and mean CDVA after 60mo were 20/22 and 20/20 respectively (P>0.01). In the PRK group mean UDVA and mean CDVA at 60mo follow-up were 20/20 and 20/20 after 60mo (P>0.01). The efficacy indexes were 0.87 and 0.95, and the safety indexes were 1.25 and 1.4 respectively for LASEK group and PRK group. Both standard PRK and no-alcohol LASEK offer safe and effective correction of low-moderate myopia in the long term without any statistically significant difference between the two groups.

Anterior segment optical coherence tomography evaluation of corneal epithelium healing time after 2 different surface ablation methods.

Objectives:To compare epithelial healing time following laser epithelial keratomileusis (LASEK) and photorefractive keratectomy (PRK) with anterior segment optic coherence tomography (AS-OCT).Methods:This prospective interventional case series study comprised 56 eyes of 28 patients that underwent laser refractive surgery in the Department of Ophthalmology, Medipol University Medical Faculty, Istanbul, Turkey, between March 2014 and May 2014. Each patient was randomized to have one eye operated on with PRK, and the other with LASEK. Patients were examined daily for 5 days, and epithelial healing time was assessed by using AS-OCT without removing therapeutic contact lens (TCL). Average discomfort scores were calculated from ratings obtained from questions regarding pain, photophobia, and lacrimation according to a scale of 0 (none) to 5.Results:The mean re-epithelialization time assessed with AS-OCT was 3.07±0.64 days in the PRK group, 3.55±0.54 days in the LASEK group, and the difference was statistically significant (p=0.03). Mean subjective discomfort score was 4.42±0.50 in the PRK eyes, and 2.85±0.44 in the LASEK eyes on the first exam day (p=0.001). The score obtained on the second (p=0.024), and third day (p=0.03) were also statistically significant. The fourth (p=0.069), and fifth days scores (p=0.1) showed no statistically significant difference between groups.Conclusion:The PRK showed a statistically significant shorter epithelial healing time, but had a statistically significant higher discomfort score until the postoperative fourth day compared with LASEK.

Long term results of Epi-LASIK and LASEK for myopia

To evaluate the long term clinical and confocal results of mechanical (Epi-LASIK) versus alcohol-assisted laser epithelial keratomileusis (LASEK) for correction of myopia. Gazi University Medical School, Department of Ophthalmology, Ankara, Turkey. Retrospective study. Twenty-two eyes treated with LASEK and twenty eyes treated with Epi-LASIK were evaluated with a mean follow-up duration of 45 months. Mechanical separation of the epithelium was performed with Lasitome epithelial separator, and alcohol-assisted separation with 25s application of 18% alcohol. Laser ablation was performed with the ESIRIS laser. All patients were examined daily until epithelial closure; at 1, 3, 6, and 12 months; and every year subsequently. Main outcome measures were uncorrected visual acuity (UCVA), manifest refraction, haze, and gray scale value in confocal microscopy, efficacy and safety indexes. Preoperative myopic spherical equivalent refraction was -4.65 ± 1.74 D in the LASEK and -3.87 ± 1.30 D in the Epi-LASIK-treated eyes (p=0.36). Of both LASEK and Epi-LASIK-treated eyes, 95% achieved 20/25 or better final UCVA. The grade of haze and mean gray scale value in confocal microscopy were similar in LASEK and Epi-LASIK-treated eyes at all postoperative periods. The efficacy index was 0.94 in LASEK group and 0.96 in Epi-LASIK group (p=0.44). The safety index was 1.01 in LASEK group and 1.02 in Epi-LASIK group (p=0.42). Both LASEK and Epi-LASIK offer safe and effective correction of myopia in the long term.

Changes in Spherical Aberration after Various Corneal Surface Ablation Techniques

PurposeThe corneal change induced by refractive procedures influence both the postoperative refractive status and the ocular spherical aberration (SA). We evaluated changes in corneal SA after three types of surface ablation: phototherapeutic keratectomy (PTK), myopic photorefractive keratectomy (PRK), and myopic wavefront-guided laser epithelial keratomileusis (LASEK).MethodsTwenty-six eyes (25 patients) were subjected to PTK 26 eyes (14 patients) to PRK, and 34 eyes (17 patients) to wavefront-guided LASEK. Corneal SA was measured with the iTrace in all patients both preoperatively and 6 months postoperatively.ResultsSix months after surgery, mean corneal SA was -0.173 ± 0.171 µm in the PTK group, 0.672 ± 0.200 µm in the PRK group, and 0.143 ± 0.136 µm in the wavefront-guided LASEK group. The mean difference between the preoperative and postoperative corneal SA (ΔSA) was -0.475 µm in the PTK group, 0.402 µm in the PRK group, and -0.143 µm in the wavefront-guided LASEK group.ConclusionsSurgically induced changes in corneal SA vary with procedure. The prediction of the pattern of SA change induced by various surface ablation procedures may be helpful for developing future surgical procedures.

Retrospective analysis of changes in the anterior corneal surface after Q value guided LASIK and LASEK in high myopic astigmatism for 3 years

BackgroundTo compare the corneal high-order aberrations (HOAs), asphericity and regularity after Q-value guided laser in situ keratomileusis (LASIK) and laser epithelial keratomileusis (LASEK) in high myopic astigmatism.MethodsIn this retrospectively comparative study, we measured the corneal HOAs, asphericity indices (Q values) and corneal regularity indices preoperatively and 36 months postoperatively in 70 eyes (35 patients) with Q-value guided surgeries. All the patients with high myopic astigmatism were divided into two groups which included 34 eyes underwent LASIK and 36 eyes underwent LASEK procedures. The main impact factors of the high-order aberrations were also analyzed.ResultsIn the two groups, the efficacy index was more than 1.00 and safety index approached 1.00 at year 3 postoperatively. Statistically significant (P < 0.05) increased in Q values and main corneal HOAs (spherical aberrations and coma) following Q-value guided LASIK and LASEK procedures. Spherical aberrations increased more in the LASEK group and there was statistically difference compared to the LASIK group (P < 0.05). LASEK had better effects in correcting corneal astigmatism (P < 0.05). All the corneal regularity indices after surgeries increased and there was no significant difference (P = 0.707, P = 0.8 and P = 0.224, respectively) between the two groups. The main impact factors of spherical aberration included the optic zone size, changes of Q value, surgical procedure and the corrected refraction.ConclusionsIn high myopic astigmatism, Q-value guided ablation showed good safety, efficacy and predictability. Q value, regularity indices, spherical aberration and coma increased in both LASIK and LASEK procedures. Astigmatism could be corrected more effectively by LASEK but greater spherical aberration could be created. The difference might be related to the different healing mechanisms. Optic zone size and the corrected refraction might be the main influence factors on the anterior corneal high order aberrations.

Posterior Corneal Elevation After LASIK with Three Flap Techniques as Measured by Pentacam

To evaluate and compare posterior corneal changes using elevation data obtained from Pentacam (Oculus Optikgeräte GmbH) Scheimpflug imaging in eyes undergoing LASIK with three different modes of flap creation: IntraLase femtosecond laser FS60 (Abbott Medical Optics) (femtosecond group), Amadeus (Ziemer Group AG) mechanical microkeratome (keratome group), or flap formation using 20% alcohol laser epithelial keratomileusis (LASEK) (LASEK group). Ninety myopic patients (90 eyes) undergoing refractive surgery were recruited. The change in posterior corneal elevation at 21 predetermined points in the central 5-mm area was measured using exported elevation data from the Pentacam before LASIK and 18 months postoperative and was compared among and within three modes of flap creation. Mean change in posterior elevation in the central 5-mm area was 5.13±4.16 μm for the femtosecond group, 5.78±4.42 μm for the keratome group, and 6.68±4.72 μm for the LASEK group and was similar among groups (P=.59). Change in posterior elevation before and after LASIK was not significant within any group (P=.342, P=.232, and P=.321 for the femtosecond, keratome, and LASEK groups, respectively). Preoperative spherical equivalent, central corneal thickness, ablation depth, and estimated residual bed thickness did not correlate with change in posterior corneal elevation for the femtosecond, keratome, or LASEK groups (P>.05). Using Pentacam elevation data, there were no significant changes in posterior corneal elevation following LASIK among or within the three methods of flap creation. At 18 months after LASIK, the posterior corneal surface is not displaced anteriorly significantly and is equally stable using these three surgical techniques.

Comparison of LASEK and LASIK with Thin and Ultrathin Flaps After Excimer Laser Ablation with the SCHWIND Aspheric Ablation Profile

to compare visual, refractive, and wavefront aberration outcomes of laser epithelial keratomileusis (LASEK), thin-flap LASIK (flap thickness 110 to 130 microm), and ultrathin-flap LASIK (flap thickness <110 microm) after excimer laser ablation with an aspheric ablation profile. a retrospective analysis of 97 eyes of 56 patients with myopia <6.00 diopters (D) sphere (30 eyes, alcohol-assisted LASEK; 30 eyes, LASIK 110; and 37 eyes, LASIK 130) was conducted. Surgery was performed using the SCHWIND ESIRIS Aberration-Free aspheric ablation profile and the Carriazo-Pendular microkeratome. groups were comparable preoperatively except for lower astigmatism and ocular trefoil (3,+3) in the LASIK 130 group and lower corneal thickness in the LASEK group. At 6 months postoperative, the groups were comparable for uncorrected and corrected distance visual acuity, efficacy index, safety, and refractive predictability. All groups demonstrated improved contrast sensitivity. All groups demonstrated a significant change in spherical aberration compared to preoperative levels. The induced spherical aberration was 0.057 microm/D in the LASEK group, 0.039 microm/D in the LASIK 110 group, and 0.044 microm/D in the LASIK 130 group. Other higher order aberrations did not show significant change except for a reduction in corneal trefoil (P=.034) in the LASEK group and increased ocular trefoil (P=.002) in the LASIK 110 group. The extent of change in higher order aberrations was not significantly different among groups. the aspheric ablation profile is safe, effective, and predictable and produces similar visual and refractive results with three different surgical approaches of LASEK, thin-flap LASIK, and ultrathin-flap LASIK. The ablation profile demonstrated a low induction rate of higher order aberrations regardless of surgical approach.

One year follow-up of contrast sensitivity following conventional laser in situ keratomileusis and laser epithelial keratomileusis

To determine the effect of conventional laser in situ keratomileusis (LASIK) and laser epithelial keratomileusis (LASEK) for myopia on contrast sensitivity (CS) using the Pelli-Robson and Vector Vision CSV-1000E CS tests. A prospective, comparative study was conducted on 36 eyes of 36 patients with myopia undergoing LASIK (18 eyes) and LASEK (18 eyes). Surgery was performed using the Technolas 217z laser (Bausch & Lomb). CS was recorded preoperatively and at 3, 6 and 12 months postoperatively. No statistically significant difference was found in LogMAR uncorrected visual acuity post-LASIK (-0.02 ± 0.16) and LASEK (-0.04 ± 0.14). Using the Pelli-Robson, CS was significantly lower in the LASIK group 3 and 6 months postoperatively. No significant postoperative reduction in CS was observed in either treatment group. Using the CSV-1000E test, CS was significantly reduced post-LASIK at 3 (p = 0.05) and 6 (p = 0.05) cycles/degree under photopic conditions. No significant postoperative change occurred in the LASEK group under photopic or scotopic conditions. There was no significant difference in postoperative CS between the LASIK and LASEK groups at 3, 6, 12 or 18 cycles/degree using the CSV-1000E test. One year postoperatively, there was no difference in CS between both treatment groups using the Pelli-Robson and CSV-1000E tests. CS was reduced postoperatively in the LASIK group at the lower spatial frequencies under photopic conditions. No postoperative change was detected in CS following LASIK or LASEK using the Pelli-Robson test.

Anterior Segment Measurements Using Pentacam and Orbscan II 1 to 5 Years After Refractive Surgery

To compare anterior segment measurements between Pentacam and Orbscan II after laser surface ablation. Corneal thickness, anterior elevation, posterior elevation, and anterior chamber depth more than 1 year after laser refractive surgery were measured using Pentacam and Orbscan II in 51 eyes that underwent laser epithelial keratomileusis (LASEK) and 21 eyes that underwent photorefractive keratectomy (PRK). As controls, the same comparisons were made in 52 unoperated eyes. Mean follow-up was 28.2 months in the LASEK group and 49.9 months in the PRK group. Mean corneal thickness using Pentacam was thicker than that using Orbscan by 10.4 microm in unoperated eyes, 22.6 microm in LASEK eyes, and 11.0 microm in PRK eyes, but the two devices showed good correlation in all groups. Mean anterior elevation was highly correlated between the two devices with 2.1-microm differences in LASEK eyes, but posterior elevation showed no correlation with significant discrepancies. Mean anterior chamber depth was 0.12-to 0.14-microm thicker with Pentacam than with Orbscan, and highly correlated in all groups. Pentacam and Orbscan showed good correlations in corneal thickness, anterior elevation, and anterior chamber depth despite some differences in mean values. The two devices, however, showed no correlation in posterior elevation measurements, a difference that was greater in the postoperative groups.

Comparison Between LASEK With Mitomycin C and LASIK for the Correction of Myopia of –7.00 to –13.75 D

To compare laser epithelial keratomileusis (LASEK) and LASIK for the correction of high myopia. A prospective, single-masked study was conducted. Patients treated with LASEK to correct myopia > or = -7.00 diopters (D) (spherical equivalent manifest refraction) with a cylinder < or = -3.50 D (LASEK group) were compared to patients treated with LASIK (LASIK group) using the same excimer laser (Technolas 217C). Mitomycin C (MMC) 0.02% was applied for 1 minute in all LASEK-treated eyes. A total of 228 consecutive eyes were included in the study (114 in each group, matched for preoperative refraction). The mean preoperative spherical equivalent manifest refraction was -8.72 +/- 1.20 D in the LASEK group and -8.74 +/- 1.20 D in the LASIK group (range: -7.00 to -13.75 D) (P = .9). Uncorrected visual acuity (UCVA) was significantly lower in LASEK eyes 1, 7, and 30 days postoperatively (P = .0001 for each comparison). No significant differences were found at 3 months postoperatively in UCVA (P = .3), best spectacle-corrected visual acuity (BSCVA) (P = .2), or in the safety (P = .6) and efficacy (P = .8) indices. Uncorrected visual acuity was 1.0 or better in 34.2% of LASEK eyes and 44.7% of LASIK eyes. Spherical refraction was +0.25 +/- 0.6 D after LASEK and -0.06 +/- 0.5 D after LASIK (P = .0001). Sixty-eight percent of LASEK eyes and 79% of LASIK eyes were within +/- 0.50 D of intended refraction. No LASEK eye versus 7 LASIK eyes lost 2 lines of BSCVA. Eight LASEK eyes gained 2 or more lines of BSCVA versus 1 LASIK eye. Visual improvement after LASEK with intraoperative MMC was significantly slower than after LASIK. Visual outcomes (UCVA, BSCVA, and safety and efficacy indices) 3 months after surgery were similar with both techniques for the correction of high myopia. Ten percent more eyes after LASIK were within +/- 0.50 D of intended refraction.

PRK and Butterfly LASEK: Prospective, Randomized, Contralateral Eye Comparison of Epithelial Healing and Ocular Discomfort

&lt;H4&gt;PURPOSE&lt;/H4&gt; &lt;p&gt;To compare corneal reepithelialization, pain scores, ocular discomfort, and tear production after photorefractive keratectomy (PRK) and butterfly laser epithelial keratomileusis (LASEK).&lt;/p&gt; &lt;H4&gt;METHODS&lt;/H4&gt; &lt;p&gt;This prospective, randomized, doublemasked study comprised 102 eyes of 51 patients who underwent laser refractive surgery. Each patient was randomized to have one eye operated on with PRK and the other with butterfly LASEK. Patients were followed for 1 year.&lt;/p&gt; &lt;H4&gt;RESULTS&lt;/H4&gt; &lt;p&gt;The mean reepithelialization time in the PRK group was 4.35±0.48 days (range: 4 to 5 days) and 4.75±0.72 days (range: 4 to 6 days) in the butterfly LASEK group (&lt;i&gt;P&lt;/i&gt;&lt;.002). Pain scores and ocular discomfort were not statistically different between groups, although a trend towards a lower pain level with PRK was noted (3.31±4.09 vs 4.43±4.27; &lt;i&gt;P&lt;/i&gt;=.18). Schirmer test values were significantly reduced from preoperative levels through 12 months with both PRK (23.6±8.1 vs 19.4±10.1; &lt;i&gt;P&lt;/i&gt;&lt;.002) and butterfly LASEK (22.4±8.7 vs 18.9±9.7; &lt;i&gt;P&lt;/i&gt;=.01); however, no difference between groups was noted at any time.&lt;/p&gt; &lt;H4&gt;CONCLUSIONS&lt;/H4&gt; &lt;p&gt;Photorefractive keratectomy showed a modest but statistically significant shorter reepithelialization time and a tendency towards lower pain scores than butterfly LASEK. The reepithelialization time was strongly associated with the duration of surgery in both techniques. A similar reduction of Schirmer test values was observed up to 1 year postoperatively in both groups. [&lt;cite&gt;J Refract Surg&lt;/cite&gt;. 2008;24:591-599.]&lt;/p&gt; &lt;h4&gt;ABOUT THE AUTHORS&lt;/h4&gt; &lt;p&gt;From Sadalla Amin Ghanem Eye Hospital (Ghanem, G.C. Souza, D.C. Souza) and the University of Joinville (Viese, Weber), Joinville, Santa Catarina; and the Department of Ophthalmology, University of São Paulo and the State University of Campinas (Kara-José), São Paulo, Brazil.&lt;/p&gt; &lt;p&gt;The authors have no financial or proprietary interest in the materials presented herein.&lt;/p&gt; &lt;p&gt;Correspondence: Vinícius C. Ghanem, MD, Rua Fernando de Noronha, 225 apart. 901, Centro Joinville/SC 89203-072, Brazil. Tel: 55 47 34226010; Fax: 55 47 34228315; E-mail: &lt;a href="mailto:vcghanem@hotmail.com"&gt;vcghanem@hotmail.com&lt;/a&gt;&lt;/p&gt; &lt;p&gt;Received: December 21, 2006&lt;/p&gt; &lt;p&gt;Accepted: July 6, 2007&lt;/p&gt; &lt;p&gt;&lt;b&gt;Posted online: February 29, 2008&lt;/b&gt;&lt;/p&gt;

Recovery of corneal sensitivity in extremely high myopia after laser sub-epithelium keratomileusis

To evaluate the changes in corneal sensitivity following laser epithelial keratomileusis (LASEK) and epiploic laser in situ keratomileusis (Epi-LASIK) in treatment of extremely high myopia. Thirty-seven eyes of 37 patients underwent LASEK and Epi-LASIK to correct myopia, their equivalent sphere ranged from -9.50 DS to -12.50 DS, astigmatism < +/- 1.50 DC. Cornea sensitivity was measured with a Cochet-Bonnet esthesiometer at central part of the cornea. Treated eyes were divided into two groups by different operation methods: Epi-LASIK group and LASEK group. After the operation, each group was divided into two sub-groups according to the eyes with or without obvious epithelium edema. Obvious epithelium sheet edema happened in 6 eyes after LASEK and 3 eyes among them were due to broken epithelium sheets during the operation. By 2 weeks, 1, 2, 3 and 6 months after Epi-LASIK, corneal sensitivity recovered to 79.31%, 84.49%, 87.92%, 92.24% and 93.98% of preoperative level, respectively. Compare to the Epi-LASIK, cornea sensitivity after LASEK recovered to 69.64%, 78.57%, 83.21%, 85.70% and 87.86% of preoperative level, respectively. The recovery of corneal sensation in LASEK group was slower than that of Epi-LASIK group. The difference between these two groups was statistically significant at 2 weeks after the operation (P < 0.05). In LASEK group, there was a trend towards a great reduction in corneal sensitivity in epithelium edema eyes and the recovery was slower in these eyes. The difference of corneal sensitivity recovery between these two sub-groups was statistically significant (P < 0.05). The recovery of corneal sensitivity in extremely high myopia after Epi-LASIK is faster than that after LASEK, and reached to the platform stage by 3 months. The epithelium sheet edema after LASEK affects corneal sensitivity recovery.

Comparison of Corneal Nerve Regeneration and Sensitivity Between LASIK and Laser Epithelial Keratomileusis (LASEK)

To compare changes in corneal nerve fibers and keratocyte density by confocal microscopy after laser-assisted in situ keratomileusis (LASIK) and laser epithelial keratomileusis (LASEK). Prospective, nonrandomized comparative clinical trial. Fifty-six eyes of 28 patients who underwent LASIK and 52 eyes of 26 patients who underwent LASEK were included. Confocal microscopic data of the central cornea, corneal sensitivity, tear film breakup time, and Schirmer values were determined at three and six months after LASIK or LASEK treatment. In the LASIK group, corneal sensitivity was reduced from preoperative levels at six months after surgery. In the LASEK group, however, there was no difference between baseline and six-month postoperative values. The number of subbasal nerve fibers and the keratocyte density were also different in the LASIK and LASEK groups. The regeneration of corneal nerves correlated strongly with the recovery of corneal sensation and keratocyte density in both groups, whereas the tear film breakup time, Schirmer values, and epithelial thickness did not correlate with corneal nerve regeneration in either group. The greater decrease in the number of subbasal nerve fibers in the LASIK group compared with the LASEK group may relate to the greater decrease in corneal sensitivity. The pattern of corneal nerve regeneration and the recovery of corneal sensation after LASEK did not differ greatly from that after photorefractive keratectomy in previous studies.

A comparative study of post-operative pain in laser epithelial keratomileusis versus photorefractive keratectomy

To compare the level of post-operative pain associated with two methods of excimer laser corneal refractive surgery: PRK (photorefractive keratectomy) versus LASEK (laser epithelial keratomileusis). 14 patients undergoing simultaneous bilateral myopic PRK were included in the study. The first eye of each patient was randomly allocated for treatment by either LASEK or PRK with alcohol-assisted epithelial debridement and second eyes were treated with the other technique. Laser corneal ablation was performed with Nidek EC-5000 excimer laser by one surgeon (MAA) using the same algorithm. Post-operatively, all patients had declofenac sodium 0.1% eye drops four times a day, lorazepam 2mg at night and two solpadol (paracetamol 500mg and codeine phosphate 30mg) tablets every six hours orally for two days. Chloramphenicol 0.5% drops four times a day were also administered for seven days. The level of pain in each eye was assessed 2, 12, 24 and 48 hours following laser surgery using a descriptive pain score from 0 to 10. Statistical analysis was performed using paired t test. The mean pain score at two hours post-operatively was 3.5 +/- 2.24(SD) in the LASEK group and 5.7 +/- 2.02(SD) in the PRK group. This difference is statistically significant. At 12 hours it was 4.33 +/- 2.53 (SD) and 4.75 +/- 2.30 (SD), at 24 hours it was 3.71 +/-2.84 (SD) and 4.00 +/- 2.48 (SD), and at 48 hours it was 2.86 +/- 3.43 (SD) and 2.21 +/- 2.55 (SD). There was no statistically significant difference in the pain score at these intervals. Post-operative pain was less in eyes treated with LASEK than eyes treated with PRK 2 hours following laser surgery. This was statisticaly significant and there was no statistically significant difference at 12, 24 and 48 hours.