جستجوی مقالات مرتبط با کلیدواژه "corneal haze" در نشریات گروه "پزشکی"

The effect of mitomycin-C (MMC) on the reduction of endothelial cell count in the cornea remains controversial. We aimed to evaluate the effect of MMC on corneal endothelial cell parameters after refractive surface ablation procedures, including photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK).

In this interventional, comparative, follow-up study, 342 eyes of 171 patients were followed up for 6 months. Patients undergoing PRK or LASEK were included and were divided into two groups: group one (188 eyes of 94 patients) with an ablation depth of ≥ 65 μm and who received intraoperative 0.02% MMC for 30 s, and group two (154 eyes of 77 patients) with an ablation depth of < 65 μm and who received balanced salt solution for 30 s. Changes in endothelial cell density (ECD), central corneal thickness (CCT), coefficient of variation (CV), and hexagonality values were compared between the groups at 3 and 6 months after surgery.

The mean ± standard deviaiton (SD) age of the patients was 28.11 ± 6.56 years. The mean ± SD ECD did not change significantly in either group between the baseline and at 3 and 6 months postoperatively. The baseline mean ECD was significantly higher in group one than that in group two (P < 0.001) and remained so at 3 (P = 0.002) and 6 months (P = 0.022) postoperatively. The baseline hexagonality value was lower in group one (P = 0.173), with a gradual decrease during the postoperative follow-up as compared with that in group two (P = 0.016 and 0.001 at 3 and 6 months postoperatively, respectively). Group one had a significantly lower CCT at 3 and 6 months postoperatively (both P < 0.001) and a higher mean CV (3 months: P = 0.028; 6 months: P = 0.328).

A single intraoperative application of MMC for 30 s as prophylaxis for corneal haze development during refractive surface ablation procedures had no significant effect on ECD up to 6 months postoperatively. Future studies with a contralateral-eye design (to neutralize factors specific to the individual patient), a larger sample size, and longer follow-up are necessary to confirm or disprove our observations.

To evaluate postoperative corneal haze and corneal densitometry following three different corneal cross-linking (CXL) protocols; standard, accelerated, and trans‑epithelial (TE).

The study recruited 104 eyes (53 patients) with progressive keratoconus divided into three groups: Group I were subjected to standard CXL, Group II to TE‑CXL, and Group III to accelerated CXL (A‑CXL) (10 mW/cm2 for 9 min). Subjective and objective corneal haze measures were evaluated before and 3, 6, and 12 months post‑CXL using slit‑lamp biomicroscopy and Pentacam Sheimpflug camera.

There was a significant difference in corneal densitometry between the three groups at 3 and 6 months post‑CXL (P < 0.0001). By the 12th month, a significant statistical difference was observed only in zones (0–2 mm) and (2–6 mm) in both the anterior and the central layers. In Group I, the densitometry value of the preoperative anterior stromal layer (anterior 120 μm) was 19.42 ± 1.81. Then, it peaked at 23.12 ± 1.21 at 3 months (P < 0.0001), reached 19.82 ± 1.19 at 6 months (P = 0.007), and decreased to 19.33 ± 3.23 (P ˃ 0.05) at 12 months. In Group II, the preoperative densitometry value of the anterior layer was 19.41 ± 1.21, peaked at 19.72 ± 1.12 at 3 months (P = 0.02), reached 19.04 ± 1.18 at 6 months (P = 0.052), and increased to 19.13 ± 1.37 at 12 months (P = 0.84). In Group III, the preoperative densitometry value of the anterior stromal layer was 19.53 ± 2.23. Then, it peaked at 24.80 ± 1.08 at 3 months (P < 0.0001), decreased to 21.75 ± 1.11 at 6 months (P < 0.0001), and reached 19.77 ± 2.26 at 12 months (P = 0.047). There was no significant correlation between the visual acuity changes and the total corneal densitometry.

The TE‑CXL group showed a better and earlier recovery from the haze, while the A‑CXL group showed a delay in recovering and persistent increased corneal densitometry, mainly in the anterior 120 µ.

To compare the outcomes of bandage contact lens (BCL) removal on the fourth versus seventh post-operative day following photorefractive keratectomy (PRK).
This study recruited eyes of patients who underwent PRK surgery. The patients were randomly assigned to 2 groups. In Group 1 BCL was removed on the 4th postoperative day, while in Group 2, BCL was removed on the 7th postoperative day. After BCL removal, patients were asked to express their pain score and eye discomfort. At one and three months follow-up examinations, visual acuity scale was assessed. Slit-lamp examination was performed in all visits to evaluate complications.
260 eyes of 130 patients underwent PRK. The age and sex ratio were not significantly different between the two groups. One month after the surgery, the logMAR uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were significantly lower in Group 2 (P value = 0.016, 0.001 respectively), however, the UDVA and CDVA were not significantly different after 3 months (P > 0.05). In Group 1, filamentary keratitis (FK) was observed in 10 (7.6%) eyes, 6 (4.61%) eyes were diagnosed with recurrent corneal erosion (RCE) and corneal haze was detected in 3 (2.3%) eyes. However, in Group 2, RCE was observed in 4 (2.3%) and FK was noted in 4 (3.07%) eyes. No haze was seen in Group 2. The difference in rate of complications was statistically significant (14.6% and 6.1% in Groups 1 and 2, respectively, P = 0.02). Pain and eye discomfort scores were not significantly different (P > 0.05). There was no major complications including infectious keratitis in either groups.
Following PRK surgery, BCL removal on the seventh postoperative day yields faster visual rehabilitation and lower rate of postoperative complications with no increase in eye pain, discomfort or infection.

To compare the efficacy and side effects of loteprednol versus fluorometholone after myopic photorefractive keratectomy (PRK).
One hundred and twenty four eyes of 62 patients who underwent PRK were enrolled in this study. One eye of each subject was randomized to receive loteprednol 0.5% and the fellow eye was given fluorometholone 0.1%. Patients were followed up for three months.
There was no significant difference in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, corneal haze, intraocular pressure (IOP), and ocular discomfort and redness between groups at the final visit. At 3 months postoperatively, 20/25 or better UDVA was achieved in 95% of the loteprednol group and 92% of the fluorometholone group (P > 0.05). There was neither visually significant corneal haze nor ocular hypertension (IOP rise > 10 mmHg or IOP > 21 mmHg) in any group.
The efficacy and side effects of loteprednol 0.5% and fluorometholone 0.1% after myopic PRK are comparable.

Keratoconus is an asymmetric, bilateral, progressive noninflammatory ectasia of the cornea that affects approximately 1 in 2000 of the general population. This may cause a significant negative impact on quality of life. Corneal collagen crosslinking (CXL) is one of the recently introduced methods that have been used to decrease the progression of keratoconus, in particular, as well as other corneal-thinning processes.

A total of 44 keratoconic eyes of 22 patients were enrolled in this randomized prospective study, after obtaining informed consent. In the first group, the corneal epithelium were totally removed and in the second group, the central 3 mm of epithelium was kept intact and partial removal was performed. After collagen crosslinking in both groups, comprehensive ophthalmologic examination was performed on all patients before and 6 months after the surgery. This article is registered at www.clinicaltrial.gov with registration number NCT01809977.

The difference between the two groups was not statistically significant regarding postoperative corneal haziness, refraction, and visual acuity (P > 0.05). However, comparison of pre- and postoperative parameters within each group revealed that total removal of the cornea has resulted in significant improvement of K-max (P value: 0.01) and Q-value (P value: 0.009); while eyes in partial removal group had better improvement of corrected vision (P value: 0.006). Both methods had significant and similar increase in optical corneal density (P < 0.0001).

In our study, keeping the central corneal epithelium intact was not beneficial for decreasing corneal haziness, however, this method caused better improvement in corrected vision. Total epithelium off technique resulted in better improvement of K-max and Q-value.

To compare the postoperative results of Epi-LASIK and photorefractive keratectomy-mitomycin (PRK-mitomycin) in patients with moderate to high myopia For this double-blind clinical trial, samples were randomly selected among those subjects above 20 years of age who were visited for myopia correction and had a spherical equivalent between -4 to -8 D. We randomly performed PRK-mitomycin in one eye and Epi-LASIK in the other eye of the patients. Refraction examinations, visual acuity (VA) measurements, contrast sensitivity testing, and corneal examination were performed at 1, 3, and 6 months after surgery. In the current study, analysis was performed on 3- and 6-month data. Thirty - six eyes were studied. Six months after surgery, the mean spherical equivalent in PRK-mitomycin and Epi-LASIK groups was 0 and -0.1 D, respectively (p=0.994). Six months after surgery, 13 eyes had a spherical equivalent of 0±0.5 D in each group while one diopter of ametropia was seen in 16 and 15 eyes in the PRK-mitomycin and Epi-LASIK groups, respectively. Six months after surgery, one eye in the PRK-mitomycin group and two eyes in the Epi-LASIK group lost 1 line of best corrected visual acuity (BCVA). Six months after surgery, 12 eyes in the PRK-mitomycin group and nine eyes in the Epi-LASIK group had an uncorrected visual acuity (UCVA) of 10/10. The safety index in the PRK-mitomycin and Epi-LASIK group was calculated to be 1.25 and 1.19, respectively (p=0.480). No haze was seen in the PRK-mitomycin group 6 months after surgery while 2 cases in the Epi-LASIK group had haze grade 0.5. There was no significant difference in contrast sensitivity between the two groups (p>0.05). The two methods were similar in postoperative VA and refractive results. Since the chance of haze formation in Epi-LASIK surgery without the application of mitomycin-C (MMC) is similar to PRK with mitomycin, Epi-LASIK can be considered as an alternative to PRK with MMC for the treatment of moderate to high myopia.

Photorefractive keratectomy is a popular mean to correct refractive errors of the eye and haze formation is one of the most important complications of the surgery. Although standard dose of intraoperative Mitomycin C has shown to be effective in reduction of this complication, potential side effects of Mitomycin C promote us to show if the lower concentration of Mitomycin C has t he same effect. 170 eyes of 85 patients enrolled in our prospective interventional study. In each patient one eye randomly assigned to be treated by low dose intraoperative MMC (LDMMC) and other eye by standard dose MMC (SDMMC). Then the patients were followed up to 6 months and refraction, Uncorrected Distant Visual Acuity (UCDVA), Best Corrected Distant Visual Acuity (BCDVA) and haze formation submitted in each postoperative exam. The results from two arms of the study compared by means of statistical methods to reveal if there was a significant difference between two groups. The mean preoperative refraction in LDMMC eyes was –3.08 (SD 1.65) sphere and 0.92 (SD 0.88) cylinder. These values for SDMMC eyes were –3.25 (SD 1.80) sphere and 0.81 (SD 0.84) cylinder. Mean postoperative sphere in LDMMC group was –0.132 (SD 0.503) and –0.138 (SD 0.484) in 3 and 6 months after PRK. These results was –0.041 (SD 0.501) and –0.076 (SD 0.489) for SDMMC group. Mean postoperative cylinder 3 and 6 month after PRK was 0.435 (SD 0.218) and 0.423 (SD 0.255) In LDMMC group and 0.435 (SD 0.247) and 0.426 (SD 0.261) in SDMMC group. In third month 14 eyes in LDMMC group presented with grade 1 score of clinical haze. From these eyes only 2 still had this haze after 6 month. 7 eyes in SDMMC group had grade 1 clinical haze at third month‑ but no clinical haze was seen at the end of 6th month. Findings of this study show no meaningful differences in postoperative rate of haze formation by use of standard and low dose intraoperative Mitomycin C. regarding these results low dose Mitomycin C with its lower side effects seems to be superior to standard dose in photorefractive keratectomy.