To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. ...To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 401%) and female 82(144 eyes, 599%). The preoperative spherical equivalent refractive errors ranged from -125D to -1000 (mean -467163D), and astigmatism ranged from 0 to -200D (means -033045D). We divided the patients into two groups according to the referaction: group A (from -125D to -590D) and group B(from -600 to -1000D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 689% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90 %, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 359%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 051 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 05 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 329%, 848%, 628%,90% and 28% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -1000D in Chinese patients, and the effect was better in myopia lower than -600D.展开更多
AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia....AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.展开更多
AIM: 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.METHODS: Twenty-five ey...AIM: 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.METHODS: Twenty-five eyes treated with LASEK and twenty-five eyes treated with PRK were evaluated with a mean follow-up duration of 60 mo. 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 12 mo, 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.RESULTS: Twenty-one eyes and 22 eyes completed follow-up of 60 mo in LASEK and PRK group respectively. Manifest refraction at 60 mo follow-up was-0.01 and 0.26 in LASEK and PRK group respectively. In the LASEK group mean UDVA and mean CDVA after60 mo were 20/22 and 20/20 respectively(P 】0.01). In the PRK group mean UDVA and mean CDVA at 60 mo 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 were1.25 and 1.4 respectively for LASEK group and PRK group.CONCLUSION: 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.展开更多
Objective To evaluate the corneal healing of non-epuality diopter response histopathologically, immunohistochemically and ultrastructurally after excimer laser photorefractive keratectomy(PRK) with SVS APEX PLUS(Summi...Objective To evaluate the corneal healing of non-epuality diopter response histopathologically, immunohistochemically and ultrastructurally after excimer laser photorefractive keratectomy(PRK) with SVS APEX PLUS(Summit Technology Inc. USA) excimer laser, and the effects of corticosteroid on the healing. Methods PRK on 6 white rabbits(12 eyes) was performed on right eye or the rabbit for an attampted correction or -4.00 diopter and on left eye for an attempted correction of -8.00 diopter. The rabbits were divided into 2 groups randomly and each group included 6 eyes: Group FLM (3 rabbits, 6 eyes) and group CM (3 rabbits, 6 eyes). Fluoromethalone was given to group FLM,and chloromycetin to group CM. On 10d, 30d and 100d,the eyes of one rabbit in each group were enucleated randomly. Half of each cornea was prepared for electron microscope observation (SEM and TEM) and the rest embedded in OCT compound for immunohistochemical study to examine Ⅲ-C and FN. Results All eyes were reepithelialized within 3d after PRK. Subepithelial corneal haze was observed on 15d,which was dominant on 30 or 60d. On 100d postoperatively,corneal hazes of 11 eyes were grades 0 or 0.5,only 1 eye(the left eye or group CM) was denser haze (grade 1). On 3d postoperatively, one or two layers of corneal epithelial cell covered the ablation zone. On 30d after PRK,the epithelial cells showed hyperplastic changes. The cells were larger and increased from normal 5 or 6 layers to 7 or 8 layers of cells on l00d after PRK,epithelium was clear with more bright epithelium. Mi- croplicae and microvilli were less than before. The expression of Ⅲ-C and FN in group CM was significantly more evi- dent than that in group FLM. Conclusion The study show that despite recovery of a continuous and smooth epithelial layer and nearly normal corneal tissues on 100d after PRK,abnormalities of both epithelium and superficial stroma can be detected in the area of ablation. The ablation depth of stroma can influence the appearance of corneal haze af- ter PRK. The microplicae and microvilli of rabbit cornea epithelium become less after PRK,which can be one of cause leading to ocular dry sensation in some patients.展开更多
To evaluate the effect of phototherapeutic keratectomy combined with photorefractive ker- atectomy in the treatment of myopia with corneal scars, corneal epithelium was removed with laser plus scraping. Corneal scars...To evaluate the effect of phototherapeutic keratectomy combined with photorefractive ker- atectomy in the treatment of myopia with corneal scars, corneal epithelium was removed with laser plus scraping. Corneal scars were removed with PTK, followed by PRK for myopia. Healon was used to make corneal surface smoother during operation. 30 eyes of 24 cases of myopia with corneal scars were followed up for one year. Mean corrected vision was 0. 51 and myopic degree was -6. 42D ±4. 26D before operation. After operation, corneal scars of 21 eyes (70. 0%) were removed in oper- ative zone. The vision of 27 operated eyes (90. 0%) was equal to or better than best corrected vi- sion. Mean postoperative visual acuity was 0. 72. Corneal surface was smoother and astigmatism was reduced after the surgery. Our study showed that PTK combined with PRK is a safe and effective treatment for myopia with corneal scars.展开更多
A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to-6.00D, 587 eyes), uncorrected visual acuity was improved ...A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to-6.00D, 587 eyes), uncorrected visual acuity was improved to 20 / 20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of±1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20 / 20 or better and 89.4% of the eyes were within ±1.00D. The designed predictability of the two groups was the same (P>0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by conical topography and modulation by steroid.展开更多
文摘To evaluate the efficacy and accuracy of photorefractive keratectomy (PRK) for myopia and myopic astigmatism .SVS APEX excimer laser with a wave length of 193 nm(Sumit Technology Inc. Waltham, Mass, USA) was applied. 316 myopic eyes of 168 patients were treated with PRK between September, 1996 and October, 1997, and 260 eyes (84%) of 150 patients were followed for more than three months, including male 68(116 eyes, 401%) and female 82(144 eyes, 599%). The preoperative spherical equivalent refractive errors ranged from -125D to -1000 (mean -467163D), and astigmatism ranged from 0 to -200D (means -033045D). We divided the patients into two groups according to the referaction: group A (from -125D to -590D) and group B(from -600 to -1000D). The number of eyes in the two groups were 220 and 40 respectively. In group A, on the 10th day, 689% has the uncorrected visual acuity (UCVA) equal to or one line better or lower than the preoperative best corrected visual acuity (BCVA). In 1,3,6 and 12 months, 90 %, 96%, 95% and 94% had the UCVA equal to or one line better or lower than the preoperative BCVA respectively. In group B, on the 10 th day, in 1,3,6 and 12 months, UCVA equal to or one line better or lower than the preoperative BCVA occurred in 359%, 83%, 87%, 86%, and 84% of the cases respectively. Most of the haze showed 051 grades except 3 eyes with the haze of 2 grade in 3 or 6 months and it changed to 1 and 05 grade respectively within one year. In 10 days and 1,3,6,12 months postoperatively, the corneal haze was noted in 329%, 848%, 628%,90% and 28% of the treated eyes respectively. We found that 193 nm excimer laser PRK was a predictable, safe, stable, and effective refractive surgery for correcting myopia up to -1000D in Chinese patients, and the effect was better in myopia lower than -600D.
文摘AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.
文摘AIM: 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.METHODS: Twenty-five eyes treated with LASEK and twenty-five eyes treated with PRK were evaluated with a mean follow-up duration of 60 mo. 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 12 mo, 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.RESULTS: Twenty-one eyes and 22 eyes completed follow-up of 60 mo in LASEK and PRK group respectively. Manifest refraction at 60 mo follow-up was-0.01 and 0.26 in LASEK and PRK group respectively. In the LASEK group mean UDVA and mean CDVA after60 mo were 20/22 and 20/20 respectively(P 】0.01). In the PRK group mean UDVA and mean CDVA at 60 mo 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 were1.25 and 1.4 respectively for LASEK group and PRK group.CONCLUSION: 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.
文摘Objective To evaluate the corneal healing of non-epuality diopter response histopathologically, immunohistochemically and ultrastructurally after excimer laser photorefractive keratectomy(PRK) with SVS APEX PLUS(Summit Technology Inc. USA) excimer laser, and the effects of corticosteroid on the healing. Methods PRK on 6 white rabbits(12 eyes) was performed on right eye or the rabbit for an attampted correction or -4.00 diopter and on left eye for an attempted correction of -8.00 diopter. The rabbits were divided into 2 groups randomly and each group included 6 eyes: Group FLM (3 rabbits, 6 eyes) and group CM (3 rabbits, 6 eyes). Fluoromethalone was given to group FLM,and chloromycetin to group CM. On 10d, 30d and 100d,the eyes of one rabbit in each group were enucleated randomly. Half of each cornea was prepared for electron microscope observation (SEM and TEM) and the rest embedded in OCT compound for immunohistochemical study to examine Ⅲ-C and FN. Results All eyes were reepithelialized within 3d after PRK. Subepithelial corneal haze was observed on 15d,which was dominant on 30 or 60d. On 100d postoperatively,corneal hazes of 11 eyes were grades 0 or 0.5,only 1 eye(the left eye or group CM) was denser haze (grade 1). On 3d postoperatively, one or two layers of corneal epithelial cell covered the ablation zone. On 30d after PRK,the epithelial cells showed hyperplastic changes. The cells were larger and increased from normal 5 or 6 layers to 7 or 8 layers of cells on l00d after PRK,epithelium was clear with more bright epithelium. Mi- croplicae and microvilli were less than before. The expression of Ⅲ-C and FN in group CM was significantly more evi- dent than that in group FLM. Conclusion The study show that despite recovery of a continuous and smooth epithelial layer and nearly normal corneal tissues on 100d after PRK,abnormalities of both epithelium and superficial stroma can be detected in the area of ablation. The ablation depth of stroma can influence the appearance of corneal haze af- ter PRK. The microplicae and microvilli of rabbit cornea epithelium become less after PRK,which can be one of cause leading to ocular dry sensation in some patients.
文摘To evaluate the effect of phototherapeutic keratectomy combined with photorefractive ker- atectomy in the treatment of myopia with corneal scars, corneal epithelium was removed with laser plus scraping. Corneal scars were removed with PTK, followed by PRK for myopia. Healon was used to make corneal surface smoother during operation. 30 eyes of 24 cases of myopia with corneal scars were followed up for one year. Mean corrected vision was 0. 51 and myopic degree was -6. 42D ±4. 26D before operation. After operation, corneal scars of 21 eyes (70. 0%) were removed in oper- ative zone. The vision of 27 operated eyes (90. 0%) was equal to or better than best corrected vi- sion. Mean postoperative visual acuity was 0. 72. Corneal surface was smoother and astigmatism was reduced after the surgery. Our study showed that PTK combined with PRK is a safe and effective treatment for myopia with corneal scars.
文摘A total of 750 six-month follow-up records of myopia treated with excimer laser photorefractive keratectomy (PRK) were analyzed. By 6 months, in group 1 (up to-6.00D, 587 eyes), uncorrected visual acuity was improved to 20 / 20 or better in 86.7% of treated eyes and 95.4% fell into the range of refraction of±1.00D. In group 2 (-6.25D to -11.00D, 163 eyes), 74.5% of treated eyes had uncorrected visual acuity of 20 / 20 or better and 89.4% of the eyes were within ±1.00D. The designed predictability of the two groups was the same (P>0.1). The refractive stability from 3 to 6 months between the two groups was not statistically different, and no severe complications were observed in these two groups. The excimer laser PRK for correcting myopia up to -11.00D appears to be effective, predictable, stable and safe in this study. The ideal outcome may result from the precise ablation quality of excimer laser, its computerized surgical manipulation and an appropriate postoperative management including detection of refractive indices by conical topography and modulation by steroid.
