Laser Vision Correction after Radial Keratotomy: A Systematic Review and Meta-analysis.

Laser vision correction for residual refractive errors in patients with previous radial keratotomy (RK) presents a challenging task. Different techniques have been used with varying outcomes. This study aimed to systematically review published manuscripts on refractive surgeries in post-RK patients search in PubMed, Scopus, and Web of Science. The final analysis included 35 studies that described a total of 888 eyes. Our systematic review and meta-analysis demonstrated a significant improvement in uncorrected distance visual acuity (UDVA) for photorefractive keratectomy, topography-guided-PRK, wavefront-guided-PRK, and femtosecond- laser-assisted in situ keratomileusis (LASIK), while mechanical microkeratome LASIK did not yield such significant improvements. Moreover, our results suggest that hyperopic post-RK patients had a significant improvement in UDVA, whereas no such improvement was observed in myopic patients.

Early Vitrectomy: An Effective Treatment for Acute Postcataract Surgery Endophthalmitis.

Background: Endophthalmitis is a rare but a high morbid complication after cataract surgery, and a gold standard treatment is not recommended yet. In this study, we aim to evaluate the effect of early vitrectomy on the visual acuity of patients with postcataract endophthalmitis. Materials and Methods: This study was a single-arm clinical trial on 27 patients with postcataract surgery endophthalmitis. Early vitrectomy was the intervention. Visual acuity as the primary outcome was evaluated and compared at baseline, at discharge, and 1 and 3 months after the intervention. Results: From 27 patients who included in our study, six patients gain favorable visual acuity of 5/10 and above (success rate = 22%), and four of them have no improvement in their visual acuity. Retinal detachment was reported as a complication in just one case. Negative culture was a predictor for success in terms of visual acuity after the surgery. All patients who gain favorable results, presented in the first 15 days after the cataract surgery. Conclusion: The result of our study showed that, considering complete, early vitrectomy for the treatment of postcataract surgery endophthalmitis, especially for those who presented in the first 15 days of cataract surgery and for those who have negative culture is promising.

Button Battery-Induced Necrotizing Keratoconjunctivitis: Case Report.

We report a case of a 2-year-old girl who presented to the ocular emergency department with a button battery retained in the inferior fornix of the left eye for more than 48 hours. The child developed necrotizing keratoconjunctivitis, which was treated with antibiotics, amniotic membrane graft, prompt removal of button battery, and other supportive measures.

Ganglion cell complex and macular thickness layers in primary open-angle glaucoma, pseudoexfoliation glaucoma and healthy eyes: A comparative study.

PURPOSE: To investigate the differences in the ganglion cell complex (GCC) and macular thickness measurements between primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PXG), and healthy eyes with optical coherence tomography (OCT)optovue. METHODS: In this non-randomized comparative cross-sectional study, 43 healthy eyes, 68 POAG eyes, and 57 PXG eyes were included. Patients were matched for age and disease severity. OCT angiography images were obtained for automated measurement of the GCC and macular thickness layers (inner and outer). RESULTS: All GCC parameters were significantly difference between healthy and glaucomatous eyes (mild, and moderate to severe disease).There were no significant differences in GCC parameters between POAG and PXG patients except focal loss volume (FLV) after adjustment. Moderate to severe PXG eyes exhibited significantly lower GCC, larger global loss volume (GLV) values, and FLV values when compared with mild PXG eyes (p<= 0.05). We found significant thinning patterns in inner retinal thickness (fovea, parafovea, and perifovea), and total retinal thickness (parafovea, and perifovea) in moderate to severe PXG eyes when comparing with POAG eyes. Patients with moderate to severe PXG also showed significantly thinning patterns in inner retinal layers (fovea, parafovea and perifovea) and total retinal thickness (nasal parafovea) in compared to mild PXG. CONCLUSION: It appears that GCC thickness is not significantly different between POAG and PXG except FLV. Despite similar retinal thickness in mild disease, a significant reduction in total and inner retinal thickness was demonstrated in moderate to severe PXG compared to moderate to severe POAG, in fovea, parafovea and perifovea region.

Topography-guided transepithelial photorefractive keratectomy to correct irregular refractive errors after radial keratotomy.

PURPOSE: To evaluate the efficacy and safety of topography-guided transepithelial photorefractive keratectomy (PRK) in a group of patients with post-radial keratotomy (RK) showing irregular corneas. SETTING: Feiz University Hospital, Isfahan, Iran. DESIGN: Prospective case series. METHODS: Consecutive patients who had irregular astigmatism after RK with stable refraction and topography for at least 1 year were recruited. All eyes had excimer laser topography-guided single-step transepithelial PRK. The efficacy, safety, predictability, and corneal wavefront aberration changes were assessed 6 months after the surgery. Vector analysis was performed using the Alpins method to evaluate the astigmatic treatment. RESULTS: Twenty-two patients (22 eyes) were enrolled. The patients' ages ranged from 37 to 61 years (45.77 years ± 4.9 [SD]); there were 12 men (54.54%) and 10 women (45.46%). Uncorrected distance visual acuity significantly improved after 6 months of treatment (0.45 ± 0.19 logarithm of the minimum angle of resolution [logMAR] preoperatively and 0.25 ± 0.19 logMAR after 6 months) (P < .001). Moreover, the corrected distance visual acuity significantly improved at the end of the study (0.14 ± 0.13 logMAR preoperatively and 0.09 ± 0.11 logMAR after 6 months) (P = .01). Furthermore, the aberrometric values were significantly reduced at the 6-month visit (P < .001). The mean of the surgically induced astigmatism was 2.15 ± 1.44 diopters. No significant complication was observed. CONCLUSION: Topography-guided single-step transepithelial PRK is a safe and effective method for treating the irregular refractive errors in post-RK patients.

Corneal haze and visual outcome after collagen crosslinking for keratoconus: A comparison between total epithelium off and partial epithelial removal methods.

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

The effect of pterygium surgery on wavefront analysis.

BACKGROUND: Pterygium is a common disorder of the ocular surface. It causes vision impairment -usually irregular type astigmatism- through different mechanisms. In addition, it is believed that surgical excision of the pterygium improves visual problems. The appropriate method to investigate irregular astigmatism is using wavefront analysis. This study was aimed to evaluate wavefront analysis pre and post pterygium surgery. MATERIALS AND METHODS: This study was performed on 32 patients who underwent surgical excision of pterygium in January 2012. Data were recorded and compared after pre and postoperative comprehensive ophthalmologic examinations including uncorrected and best corrected visual acuity, Orbscan, wavefront analysis and autorefraction to figure out the effects of surgery on different parameters. RESULTS: Comparison of pre and postoperative parameters showed that surgical treatment of the pterygium improves numerous parameters significantly including uncorrected and best corrected visual acuity, spherical and cylinder refractive error, higher order aberration, quadrafoil (Z440), corneal astigmatism and 3 and 5 mm central zone corneal irregularity (all P-values < 0.0001). In addition, it improves vertical coma (P:0.003) and secondary astigmatism (Z420) (P:0.004). CONCLUSION: It is concluded that surgical excision of the pterygium improves visual acuity, refractive errors and most of the corneal topographic indices and wavefront analysis parameters.

Corneal astigmatism change and wavefront aberration evaluation after cataract surgery: "Single" versus "paired opposite" clear corneal incisions.

BACKGROUND: Correcting the pre-existing astigmatism is an optimal goal in cataract surgery. The aim of this study is to compare the astigmatic correcting effect of a single regular 3.2 mm clear corneal incision (CCI) with paired opposite CCI in cataract patients and effect of these incisions on optical aberrations using the wavefront quantitative analysis. MATERIALS AND METHODS: This was a randomized controlled trial study undertaken in an ophthalmology referral center on 50 patients planned for cataract surgery who were randomized to either single 3.2 mm CCI or paired opposite CCI group. Post-operative evaluation was performed at 12 weeks and included refraction, keratometery, corneal topography and wavefront analysis. Corneal astigmatism and post-operative values were compared in two groups. RESULTS: The mean pre-operative corneal astigmatism was 2.58 ± 1.03 D in the single incision group and 2.70 ± 0.94 D in the paired opposite incisions group. After 12 weeks of surgery, the corneal astigmatism was reached to 2.15 ± 0.82 D in single incision group and 1.63 ± 1.21 in the paired opposite incisions group. There was a statistically significant difference in two arms of treatment regarding to surgically induced astigmatism after 3 months. The mean post-operative total and higher order aberrations and values were not significantly different in two groups. CONCLUSION: The results of our study showed that paired opposite incisions is an effective procedure for reducing pre-existing corneal astigmatism in cataract surgery. Paired incisions did not show any beneficial effect regarding wavefront aberrations compared with conventional single incision method.