Comparison on dry eye symptoms and stability of tear film after correction of myopia by LASIK versus LASEK with the use of artificial tears / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To investigate the dry eye symptoms and the stability changes of tear film after correction of myopia by laser-assisted <i>in situ</i> keratomileusis(LASIK)and laser epithelial keratomileusis(LASEK)with the use of 0.1% sodium hyaluronate(HA).<p>METHODS:A total of 230 myopia patients(460 eyes)were divided into LASIK group and LASEK group from February 2017 to December 2017. Each operation group was randomly assigned to 0.1% HA treatment subgroup and HA-free subgroup. Both subgroups were instructed to apply gatifloxacin(0.3%)and loteprednol(0.5%)after the corneal refractive surgery. The changes of dry eye symptom score, corneal perceptual reaction, corneal fluorescein staining(FL), basic Schirmer Ⅰ test(SⅠt)and tear film break-up time(BUT)were observed in different time points.<p>RESULTS:There were significant differences in FL, dry eye symptom score and corneal perceptual response between the 0.1% HA treatment group and HA-free group at 1wk, 1, 3 and 6mo after operation both in LASIK and LASEK patients(<i>P</i><0.05). BUT after operation in each group was significantly deceased at 1wk compared with preoperative level. Other observation time points after surgery of BUT and each postoperative level of SⅠt were still within the normal range although lower than the preoperative levels. The subjective symptoms of dry eyes, tear film stability and corneal surface perception of LASEK patients were better than LASIK patients especially at 1wk, 1 and 3mo after surgery.<p>CONCLUSION:These two kinds of refractive surgery may cause different degrees of dry eye symptoms. These symptoms in the LASEK group were lighter than that in the LASIK group in the early postoperative period. The early adequate use of preservative-free 0.1% HA could effectively promote the corneal repair and be greatly helpful for postoperative dry eye symptoms.

Influence factors and clinical treatment of high intraocular pressure after LASEK / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To analyze the influence factors of high intraocular pressure after laser epithelial keratomileusis(LASEK), and to discuss the clinical treatment and prognosis of the high intraocular pressure patients. <p>METHODS: A retrospective study was used. From August 2013 to February 2016, 160 LASEK patients(160 eyes)in our hospital were selected. Visual acuity after operation was recorded. The incidence and influence factors of high intraocular pressure were investigated. The treatment method and prognosis of high intraocular pressure were recorded. <p>RESULTS: In the 160 patients, all patients had complete epithelial flap and different degree of photophobia. There were 19 patients with postoperative photophobia, conjunctival hyperemia and foreign body sensation significantly. At postoperative 3mo, average intraocular pressure were 18.40±4.98mmHg, which was higher than that of preoperative, 16.27±2.24mmHg(<i>P</i><0.05), and at postoperative 3mo, visual acuity was significantly higher than preoperative(<i>P</i><0.05). There were 9 patients with postoperative steroid induced ocular hypertension, the incidence rate was 5.6%; Multiple linear regression analysis showed that the cutting depth(<i>OR</i>=3.209), maximum diameter of curvature(<i>OR</i>=3.071)and fundus C/D(<i>OR</i>=9.224)value were the main risk factors leading to postoperative steroid induced ocular hypertension(<i>P</i><0.05). <p>CONCLUSION: The postoperative steroid induced ocular hypertension in LASEK is common, but has no obvious effect on visual acuity. The cutting depth, maximum diameter, curvature fundus C/D value were the main influencing factors, so we should careful use the hormone drugs in treatment and prevention. Periodic review and detection for change of intraocular pressure are needed.

Short term effects of 1g/L bromfenac sodium eye drops after LASEK / 国际眼科杂志(Guoji Yanke Zazhi)

?AIM: To compare postoperative anti -inflammation effect and safety between bromfenac sodium eye drops and pranoprofen eye drops in patients after laser epithelial keratomileusis ( LASEK) .? METHODS: In the prospective, randomized and controlled study, 100 patients ( 200 eyes ) undergoing LASEK were randomized into the bromfenac sodium group (100 eyes) and control group (100 eyes).Patients in bromfenac sodium group received bromfenac sodium hydrate ophthalmic solution eye drops twice a day in 3d before surgery and 2wk after surgery, while the patients from the control group were given proanoprofen eye drops 4 times a day in the same period.At 1, 3, 5d, 1 and 3mo after surgery, irritative symptoms grade, duration of irritation, time for corneal epithelial healing, cornel haze, uncorrected visual acuity and intraocular pressure ( IOP ) were observed and compared between the two groups. Quantitative data were analyzed using independent samples t-test and ranked data were statistically analyzed using the Mann-Whiteney rank sun test.?RESULTS:There was no significant difference between two groups in irritative symptoms grade ( P =0.317 ), neither was existed between two groups in uncorrected visual acuity after surgery (P>0.05).There was no statistical significance in the time for corneal epithelial healing between two groups (P=0.551).?CONCLUSION: Bromfenac sodium eye drops ( 1g/L ) can achieve the same therapeutic effect as pranoprofen eye drops after LASEK.

Comparison of 10-year Clinical Results between Laser in situ Keratomileusis and Surface Ablation for Moderate to High Myopia

PURPOSE: To compare the long-term prognosis of laser in situ keratomileusis (LASIK) and surface ablation in moderate to high myopia. METHODS: A retrospective study including 87 eyes of 44 myopic patients treated with LASIK or surface ablation from 1995 to 2005 was performed. Follow-up visits were performed at 3 months, 1 year, 5 years, and 8 years. All treated eyes were divided into 2 groups according to preoperative spherical equivalent (SE)- moderate myopia (<-6.0 diopters [D]) and high myopia (≥-6.0 D). The main outcome measures were postoperative uncorrected visual acuity (UCVA), best corrected visual acuity, SE, mean keratometry, safety index, efficacy index, predictability, and complications. RESULTS: Mean SE was -7.05 ± 2.49 D in the LASIK group and -5.25 ± 1.23 D in the surface ablation group. The 10-year SE was -1.78 ± 1.22 D in the LASIK group and -1.35 ± 1.09 D in the surface ablation group, and there was no statistical difference between the 2 groups. At 10 years postoperatively, UCVA was log MAR 0.155 ± 0.161 in the LASIK group and log MAR 0.095 ± 0.140 in the surface ablation group. There were no significant differences in postoperative mean SE, safety index, efficacy index, or complications between the LASIK and surface ablation group at 10 years. CONCLUSIONS: This 10-year follow-up study shows that LASIK and surface ablation for moderate to high myopia have no statistical differences in mean SE, safety index, efficacy index, or complications.

Related research on corneal higher-order aberrations after different ways refractive surgery / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To evaluate the changes of corneal high - order aberration (including Coma, Spab, RMSh) after laser in situ keratomileusis (LASIK) with femtosecond laser, sub- Bowman keratomileusis ( SBK ) and laser epithelial keratomileusis (LASEK). METHODS: Of 82 myopic patients ( 164 eyes ), 31 patients (62 eyes) were treated by FS-LASIK, 31 patients (62 eyes) were treated by SBK, 20 patients (40 eyes) were treated by LASEK. Sirius system was used for measuring the coma aberration, spherical aberration, and high order aberration at 1, 15d,1, 3mo after surgery. RESULTS: 1) Vision: The uncorrected visual acuity of the three groups had no differences (P>0. 05). 2) Corneal aberrations: Three kinds of surgical procedure for patients with corneal aberration had significant impact. The C7, C8, C12 and RMSh of three groups were increased significantly (P<0. 05). The C7, C8, C12 and RMSh were not recovered to preoperative levels after 3mo. But the increase of patients after FS- LASIK was smaller than the other two groups, with statistical significance (P<0. 05). CONCLUSION: Compared with SBK and LASEK, FS - LASIK has better visual acuity in the early postoperative and corneal higher-order aberrations increase is relatively small.

Changes in Spherical Aberration after Various Corneal Surface Ablation Techniques

PURPOSE: The 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). METHODS: Twenty-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. RESULTS: Six months after surgery, mean corneal SA was -0.173 +/- 0.171 micrometer in the PTK group, 0.672 +/- 0.200 micrometer in the PRK group, and 0.143 +/- 0.136 micrometer in the wavefront-guided LASEK group. The mean difference between the preoperative and postoperative corneal SA (DeltaSA) was -0.475 micrometer in the PTK group, 0.402 micrometer in the PRK group, and -0.143 micrometer in the wavefront-guided LASEK group. CONCLUSIONS: Surgically 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.

Changes in Spherical Aberration after Various Corneal Surface Ablation Techniques

PURPOSE: The 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). METHODS: Twenty-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. RESULTS: Six months after surgery, mean corneal SA was -0.173 +/- 0.171 micrometer in the PTK group, 0.672 +/- 0.200 micrometer in the PRK group, and 0.143 +/- 0.136 micrometer in the wavefront-guided LASEK group. The mean difference between the preoperative and postoperative corneal SA (DeltaSA) was -0.475 micrometer in the PTK group, 0.402 micrometer in the PRK group, and -0.143 micrometer in the wavefront-guided LASEK group. CONCLUSIONS: Surgically 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.

Comparison of Photorefractive Keratectomy and Laser Epithelial Keratomileusis for Low to Moderate Myopia

PURPOSE: To compare the efficacy and safety of photorefractive keratectomy with laser epithelial keratomileusis, for low to moderate myopia. METHODS: Patients with a manifest refraction less than -6.0 diopters were enrolled in this study. Patients were treated with photorefractive keratectomy (47 eyes) or laser epithelial keratomileusis (42 eyes). Preoperative and postoperative uncorrected visual acuity, refractive errors, keratometry, residual central corneal thickness, epithelial healing time, and corneal haze were evaluated for a 1 year follow-up period. RESULTS: There were no significant differences between photorefractive keratectomy and laser epithelial keratomileusis in uncorrected visual acuity, refractive errors or correction of refractive errors. Residual central corneal thickness increased until 6 months postoperative and thereafter in both photorefractive keratectomy and laser epithelial keratomileusis groups. There were no significant changes in keratometry after postoperative 1 month. Epithelial healing time of photorefractive keratectomy was shorter than that of laser epithelial keratomileusis. Corneal haze score had a peak at 1 month postoperative and then decreased rapidly until 3 months postoperative, it was stable after 6 months. Corneal haze score at 1 month was less than 0.5 in both groups and did not disturb visual acuity. CONCLUSIONS: Photorefractive keratectomy and laser epithelial keratomileusis have an equal effect in correction of visual acuity and refractive errors. They have equivalent levels of safety as measured by postoperative residual central corneal thickness and corneal haze. Both procedures are effective methods to correct low to moderate myopia.

Short Term Clinical Results of Laser Epithelial Keratomileusis and Epi-Laser in Situ Keratomileusis for Moderate and High Myopia

PURPOSE: To compare the results of laser epithelial keratomileusis (LASEK) and epi-laser in situ keratomileusis (Epi-LASIK) for the treatment of moderate to high myopia. METHODS: In this study, 50 patients with a manifest refraction of moderate to high myopia were assigned to two groups: 50 eyes of 25 patients treated with LASEK and 50 eyes of 25 patients treated with epi-LASIK. Uncorrected visual acuity (UCVA), manifest refraction, corneal haze, and postoperative pain were reviewed in LASEK and epi-LASIK treated eyes at 3 months after the operation. RESULTS: At one week after surgery, UCVA was recovered more rapidly after epi-LASIK than LASEK (LASEK: 0.61+/-0.23, Epi-LASIK: 0.79+/-0.11, p<0.05), but UCVA at both 1 and 3 months showed no significant difference between the LASEK and epi-LASIK groups. However, epi-LASIK-treated eyes had lower postoperative pain scores and lower corneal haze scores (1 month; p=0.01) than those of LASEK-treated eyes. CONCLUSIONS: Epi-LASIK showed a more rapid visual recovery than LASEK at 1 week after surgery for the correction of myopia. Epi-LASIK-treated eyes also had less postoperative pain and an earlier reduction of postoperative corneal haze. These results suggest epi-LASIK could be a viable alternative procedure for the correction of moderate to high myopia.

Effect of Corneal Epithelial Flap on the corneal wound healing of canine eyes

PURPOSE: LASEK is a newly developed refractive surgery technique that can make up for the complications from PRK and LASIK. The most unique procedures in LASEK is covering of the cornea with epithelial flap after keratectomy. We examined the effect of corneal epithelial flap on the wound healing of canine cornea. METHODS: Operation was performed in eyes from 12 dogs, and the 12 eyes were recovered with epithelial flap and the remaining 12 eyes were recovered without epithelial flap. Wound healing process was compared using fluorescein staining, light and transmission electron microscopic examination. RESULTS: Fluorescein stained area of the cornea was reduced with time in both groups, and from 9 hours after the operation, it was significantly reduced in the group with epithelial flap compared with those of the group without epithelial flap (p< 0.05). On light microscopic examination of the group with epithelial flap, and normal epithelial structure was found at 24 and 48 hours, respectively. However, in the group without epithelial flap, no complete reepithelialization had occurred on center at 48 hours after the operation. On transmission electron microscopic examination, eyes of the group with epithelial flap showed hemidesmosomes in the area where epithelial flap was closely contacted with the stroma at 24 hours, and they were completely developed at 48 hours. On the other hand, in the group without epithelial flap, hemidesmosomes developed only in the proximal portion but not at the leading edge even at 48 hours. CONCLUSIONS: These results suggest that corneal epithelial flap accelerate the wound healing process of the cornea and the wound healing process depend on the vitality of the epithelial flap.

Comparison of Laser Epithelial Keratomileusis(LASEK) in One Eye and Photorefractive Keratectomy(PRK) in Other Eye for Low to Moderate Myopia

PURPOSE: To assess effectiveness, safety and stability of laser epithelial keratomileusis(LASEK), versus conventional photorefractive keratectomy(PRK) for low to moderate myopia. METHODS: 27 patients with a manifest refraction of -3.00 to -6.50 diopters were treated and followed-up for 3 months. In each case, one eye received PRK and the other LASEK. The surgical method and the sequence between the eyes were randomized. Postoperative pain, epithelial healing time, uncorrected visual acuity, manifest refraction, corneal haze and surgical preference were examined after the operation. RESULTS: During a 3-month-follow-up, we found no significant differences in epithelial healing time, uncorrected visual acuity and refractive error. However, LASEK treated eyes had lower postoperative pain scores(P=0.047), and corneal haze scores(1 month; P=0.02) than those of PRK. Seventeen patients(63%) preferred the LASEK procedure. CONCLUSION: LASEK and PRK has an equal effect in correction of myopia, but LASEK reduced incidence of postoperative pain and early postoperative corneal haze. This suggests LASEK can be an alternative procedure for correction of low to moderate myopia.

Western blot analysis of types Ⅰ, Ⅲ, Ⅴ, and Ⅵ collagens after LASEK and PRK in cornea of rabbits and the significance / 第三军医大学学报

Objective To observe and compare the accurate dynamic changes of types Ⅰ, Ⅲ, Ⅴ, and Ⅵ collagens in the wound healing processes of the rabbit cornea undergoing laser epithelial keratomileusis (LASEK) or photorefractive keratectomy (PRK) and to investigate the possible mechanisms of corneal haze and myopic regression. Methods New Zealand White rabbits were divided into 8 groups: normal control group (n=6), 1, 7 d, and 1, 3, 4, 5, and 6 month groups (n=14). Every rabbit underwent LASEK in one eye while the other one with PRK. We used Western blot analysis to compare the wound healing process of dynamic changes of types Ⅰ, Ⅲ, Ⅴ, and Ⅵ collagens in the rabbit cornea at every time point. The results were analyzed with data analysis software. Results Western blot analysis showed that after LASEK, the cornea wound healing with types Ⅰand Ⅲ collagens were much faster than that of PRK, and the wound response was also much weaker. Whereas for types Ⅴ and Ⅵ collagens, their dynamic changes were similar between LASEK and PRK, and they both reached the peak value at 3 month after the surgery, but LASEK group returned to normal earlier than PRK group. The value of these two types of collagens after PRK was higher than that by LASEK. The changes of these four types of collagens may offer us at least partial explanation to the difference of formation of corneal haze and refractive regression. Conclusion There are significant differences between LASEK and PRK in types Ⅰ, Ⅲ, Ⅴ, and Ⅵ collagens or the time of reacting, reaching apex, and returning to normal. LASEK has slighter intensity of reaction. The results indicate that there is excessive aggradation of collagens after PRK, which may be the histological foundation of obvious haze and myopia regression.