Fourier-domain optical coherence tomography-guided phototherapeutic keratectomy for the treatment of anterior corneal scarring

AIM:To evaluate the safety,visual and anatomic outcomes of fourier-domain optical coherence tomography(FD-OCT)-guided excimer laser phototherapeutic keratectomy(PTK)combined with photorefractive keratectomy(PRK)surgery in treating anterior corneal scarring.METHODS:Clinical data of 23 eyes of 21 patients with anterior corneal scarring underwent FD-OCT-guided PTK and PRK from Dec.2014 to Jul.2016 were reviewed.Patients were assessed for preoperative and postoperative uncorrected visual acuity(UCVA),best spectacle-corrected visual acuity(BSCVA),contrast sensitivity(CS),FD-OCT,corneal topography and colour figures of anterior segments.RESULTS:The preoperative corneal pathologic conditions included viral keratitis(7 patients,7 eyes),band keratopathy(2 patients,4 eyes),corneal dystrophy(4 patients,4 eyes),traumatic corneal disease(2 patients,2 eyes)and corneal chemical injury(6 patients,6 eyes).Mean follow-up time was 10.65(range,3-19)mo.UCVA(in IogMAR)improved from a mean of 0.79(95%Cl,0.28­1.29)preoperatively to a mean of 0.45(95%Cl,0.29-0.62)postoperatively(P=0.021).BSCVA(in IogMAR)improved from 0.57(95%Cl,0.27-0.88)preoperatively to a mean of 0.28(95%Cl,0.15-0.41)postoperatively(P=0.001).Corneal topographic indices postoperatively showed significant improvement in corneal cylinder(P=0.009),the surface regularity index(P=0.007)and surface asymmetry index(P=0.00).Postoperative spherical equivalent averaged-0.53 diopters(-1.49 to 0.42).No complications were associated with the treatment.CONCLUSION:FD-OCT-guided PTK combined with PRK is safe and effective for the treatment of anterior corneal scarring by eliminating or reducing corneal opacities.

Femtosecond laser-assisted deep anterior lamellar keratoplasty in phototherapeutic keratectomy versus the big-bubble technique in keratoconus

AIM：To compare the functional and anatomic results of femtosecond laser（FSL）-assisted deep anterior lamellar keratoplasty（DALK） associated with phototherapeutic keratectomy（PTK） and FSL-assisted DALK performed using the big-bubble technique in keratoconus.METHODS：During the first phase of the study,an electron microscopy histopathology pilot study was conducted that included four unsuitable donor corneas divided into two groups：in FSL group,FSL lamellar cuts were performed on two corneas and in FSL＋PTK group,PTK was performed at the stromal beds of two corneas after FSL lamellar cuts were made.During the second phase of the study,a randomized clinical trial was conducted that included two treatment groups of patients with keratoconus：group 1（n=14 eyes） underwent FSL-assisted DALK associated with PTK and group 2（n=12 eyes） underwent FSL-assisted DALK associated with the bigbubble technique.The main outcome measures were the postoperative visual acuity（VA） and optical coherence tomography（OCT） measurements,confocal microscopic findings,and contrast sensitivity.RESULTS：In the pilot study,histopathology showed a more regular stromal bed in the FSL＋PTK group.In the clinical trial,group 1 had significantly worse best spectaclecorrected VA and contrast sensitivity（P〈0.05 for both comparisons）.The residual stromal bed measured by OCT was significantly（P〈0.05） thicker in group 1.Confocal microscopy detected opacities only at the donor-receptor interface in group 1.CONCLUSION：Patients with keratoconus treated with FSL-assisted DALK performed using the big-bubble technique fare better than treated with FSL-assisted DALK associated with PTK.

Phototherapeutic Keratectomy Combined with Photorefractive Keratecto-my for Treatment of Myopia with 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.

Treatment of anterior corneal scarring,following DSAEK graft failure,with combined graft exchange and phototherapeutic keratectomy

Background:To present a method,alternative to penetrating keratoplasty,for the restoration of impaired corneal clarity with anterior stromal scarring following long-standing corneal graft failure.Case presentation:A 48-year old female who had previously underwent Descemet stripping automated endothelial keratoplasty(DSAEK)for the treatment of pseudophakic bullous keratopathy,presented with longstanding corneal oedema and anterior corneal scarring.A significant improvement in corrected distance visual acuity was demonstrated,as corneal clarity was restored following graft exchange and phototherapeutic keratectomy(PTK).Conclusions:The combination of corneal graft exchange and phototherapeutic keratectomy may represent an effective therapeutic option for long-standing corneal oedema with concomitant anterior corneal scarring after failure of a DSAEK graft.

Treatment of superficial corneal opacities with corneal stromal lenticule obtained through SMILE surgery

AIM:To evaluate the clinical efficacy and feasibility of superficial corneal opacities treated by excimer laser phototherapeutic keratectomy(PTK)combined with small incision lenticule extraction(SMILE)-derived corneal stromal lenticule transplantation.METHODS:A retrospective interventional case series of nine patients aged 12-59y with superficial corneal opacity caused by different pathologies who underwent standardized PTK combined with SMILE-derived corneal stromal lenticule transplantation was examined.Lenticule patches were fixed with fibrin glue.All patients underwent pre-and post-operative clinical assessments at different times for up to 12mo.Slit lamp microscopy,corneal density,uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),and anterior segment optical coherence tomography(AS-OCT)were examined.RESULTS:The patients’mean age was 36.00±5.80(12-59)y.Seven eyes(77.8%)gained UDVA and CDVA at the last measurement compared to their preoperative levels.The densities of the total cornea,the total anterior corneal layer,and the anterior corneal layers of 0-2 and 2-6 mm decreased significantly by 12.4%,27.5%,46.7%,and 32.8%,respectively.After human allogeneic transplantation,the implanted lenticules of all eyes were clearly visible by AS-OCT and remained transparent without displacement or graft rejection.The thickness of the central cornea and corneal lenticule transplants were stable throughout the entire postoperative period.One case experienced the postoperative complication of delayed corneal epithelial healing.CONCLUSION:PTK combined with SMILE-derived corneal lenticule transplantation improves long-term visual acuity.Therefore,it is a new,safe,and effective method for treating superficial corneal opacity.

Transepithelial photorefractive keratectomy mode using SCHWIND-ESIRIS excimer laser:initial clinical results

AIM: To evaluate postoperative pain, uncorrected visual acuity (UCVA), and cornea haze value after transepithelial photorefractive keratectomy (T-PRK) performed with aspherical ablation profile using SCHWIND ESIRIS excimer laser. METHODS: Retrospective case series. Fifty-nine eyes (32 patients) with myopia associated with or without astigmatism underwent phototherapeutic keratectomy (PTK) followed by photorefractive keratectomy (PRK) which performed by Optimized Refractive Keratecomy (ORK)-CAM software based on aspherical ablation profile using SCHWIND ESIRIS excimer laser. Postoperative pain scale was measured on a questionnaire through five levels. Haze was graded by five grades, and UCVA, manifest refraction spherical equivalent (MRSE) were analyzed. RESULTS: Mean pain level was (1.37 +/- 0.613) (range: 1 to 3), the mean time picking out the soft contact lens was (6.22 +/- 1.73) days, at 3 months, UCVA was 1.0 for 40 eyes (67.8%), 0.5 for all eyes (100.0%). The UCVA was significantly less than the preoperative best spectacle corrected visual acuity (BSCVA) (t=-2.84, P=0.006), haze value was (0.27 +/- 0.25), no patients had a haze grade up to 2. Mean MRSE was (0.76 +/- 0.96) diopter(D) by 3 months. CONCLUSION: The outcomes from this study show that using the SCHWIND ESIRIS aspherical ablation profile for transepithelial PRK has a good visual result. The primary advantage is related to a spherical ablation profile, automatically considers the ablation volume of the stroma and the accurate and smooth removal of the epithelium with PTK. Additional studies are needed to determine long-term outcomes.