Photorefractive Keratectomy (PRK) is Safe and Effective for Patients with Myopia and Thin Corneas

The aim of this study was to evaluate the long-term safety and efficacy of photorefractive keratectomy (PRK) for patients with myopia and thin corneas. In this retrospective case series, we included 74 eyes of 38 patients with myopia and central corneal thickness (CCT) < 550 µm who underwent PRK and had a mean postoperative follow-up period of four years. The following factors were evaluated: CCT, refraction, uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), ablation depth, safety and efficacy indices (i.e., the ratio of the mean postoperative BCVA to the mean preoperative BCVA, and the ratio of the mean postoperative UCVA to mean preoperative the BCVA, respectively), and evidence of corneal ectasia (based on Orbscan topography images).The patients were aged 20 – 46 years (mean ±SD age, 28.18± 6.82 years). The mean ± SD pre- and postoperative CCTwas485.92 ± 9.27 µm and 434.84 ± 20.48 µm, respectively. The mean ± SD pre- and postoperative myopia was -2.77 D ± 1.51 and -0.24 ± 0.39 D, respectively, and the mean ± SD pre- and postoperative astigmatism was -0.82 D ± 0.99 and -0.37 ± 0.37 D, respectively. The mean pre- and postoperative BCVA and postoperative UCVA was 0.011 ± 0.03 Logarithm of the Minimum Angle of Resolution (log MAR), 0.003 ± 0.01 log MAR, and 0.054 ± 0.09 log MAR, respectively. The mean ± SD ablation depth, safety index and efficacy index was 54.34 ± 16.28 µm, 0.02 ± 0.12, and 0.11 ± 0.50, respectively. Regarding the postoperative corneal clarity, 72 eyes (97.3%) had a clear cornea (grade 0) and the remaining two eyes of one patient (2.70%) had a trace haze (grade 1). There was no evidence of corneal ectasia on any of the Orbscan topography images. Thus, among patients with myopia and thin corneas (<500 µm), PRK seems to be acceptable in terms of both safety and efficacy 4 years after surgery, based on the stability of postoperative refraction, visual acuity, and topographic outcomes, and outcomes based on the safety and efficacy indexes.Â

Myoring implantation alone versus corneal collagen cross-linking following myoring implantation for management of keratoconus: 1 year follow up

Purpose: To compare combined MyoRing implantation with previously corneal collagen cross-linking (CXL- MyoRing) versus MyoRing implantation alone in patients with keratoconus. Methods: This retrospective, comparative, cohort study included 33 eyes of 33 patients with keratoconus stage II and III according to Amsler-Krumeich classification. Two groups were performed for this study with 1 year follow up. The group 1 received MyoRing implantation and the group 2 received CXL approximately 12 months before MyoRing implantation. All patients had a complete pre and post-operative examination including visual, refractive and keratometry examinations. Results: In Group 1 at the end of follow up the mean UDVA and CDVA improved by 9 and 4 lines of logMAR. In Group 2 the mean UDVA and CDVA improved by 8 and 2 lines of logMAR. There was not observed a statistically significant difference between mean UDVA of two groups postoperatively (p = 0.142) whereas the mean CDVA in Group 2 was significantly better than mean Group 1 at the end of follow up (p= 0.018). Spherical equivalent error and refractive astigmatism were significantly reduced in both groups which no statistically significant differences was noted in these refractive parameters between two groups. The mean keratometric values also were reduced in both groups at the end of follow up which no statistically significant difference was observed between two groups. Conclusion: Both MyoRing implantation alone and combined MyoRing implantation with previously CXL were safe and effective methods for moderate and severe keratoconus and resulted in similar clinical outcomes after one year follow up. ExclusivelyMyoRing implantation alone demonstrated better outcome in mean CDVA

Predictability, Stability and Safety of MyoRing Implantation in Keratoconic Eyes During One Year Follow-Up

Purpose: To assess the stability of visual and refractive outcomes that was compared between three and 12 months after MyoRing implantation in moderate and severe keratoconus Methods: This study included 54 eyes of 50 patients (27 males and 23 females) with stage II and III keratoconus who underwent MyoRing (Dioptex GmbH) implantation. Clinical outcomes including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE) and mean keratometry (k)- readings were compared preoperatively and postoperatively (follow-up times were at 1, 3, 6 and 12 months postoperation). Results: The mean age was 28.48±6.3. The mean UDVA (logMAR) and the mean CDVA (logMAR) improved significantly from 1.20±0.24 to 0.20±0.09 and from 0.58±0.22 to 0.14±0.06, respectively (p<0.001). Both SE and the maximum keratometry (k)-reading decreased significantly by six diopters (p<0.001). There was no significant difference in visual and refractive outcomes between three and 12 months postoperatively. Twelve months after MyoRig implantation the predictability was 47 eyes (87%) within ±1.00 D and 31 eyes (57%) within ±0.50 D of emmetropia. Conclusion: MyoRing implantation in keratoconic patients improves SE, UDVA and CDVA significantly. Additionally, the improvement in UDVA was remarkable (approximately 10 lines). The procedure was safe and effective in treatment of patients with moderate and severe keratoconus. The visual and refractive outcomes remained stable between three and 12 months postoperatively

Evaluating the Repeatability and Effect of Sex and Age on Corneal Biomechanical Parameters Measured Using Corvis ST

AbstractPurpose: To evaluate the repeatability of biomechanical readings by Corvis ST  (Wetzlar, Germany)  in healthy eyes and its relation with age and sex.Methods: Three consecutive measurements were performed on 100 eyes of 100 patients using the Corvis ST. Various parameters including first and second applanation length, first and second applanation velocity, first and second applanation time, peak distance, radius, deformation amplitude, corrected and non-corrected intraocular pressure (IOP), central corneal thickness (CCT), Corvis ST biomechanical index (CBI), and tomography and biomechanical index (TBI) were derived from the Corvis ST readings. Repeatability of each parameter and their correlation with age and sex were evaluated.Results: The mean IOP, CCT, CBI and TBI were 15.47 ± 2.24 mm Hg, 541.24 ± 38.90 μm, 0.048 ± 0.13 and 0.138 ± 0.17 respectively. Intra class correlation coefficient (ICC) for CCT, second applanation velocity and deformation amplitude were 0.985, 0.809 and 0.825 respectively. ICC was less than 0.8 for all other parameters. The device-specific readings showed no significant relationship with age and sex.Conclusion: The Corvis ST showed high repeatability for CCT, second applanation velocity, and deformation amplitude parameters. No relation between Corvis ST readings and age or sex was observed. Keywords: Cornea; Biomechanical; Age; Sex; Iran

(2Z)-N-(4-Meth­oxy­phen­yl)-2-(4-meth­oxy­phenyl­imino)-2H-1,4-benzoxazin-3-amine

In the crystal structure of the title compound, C22H19N3O3, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into a zigzag chain parallel to the face diagonal of the ac plane. The meth­oxy phenyl rings make a dihdral angle of 32.38 (7)° and form dihedral angles of 0.66 (8) and 24.17 (7)° with the fused benzooxazine ring system

(Z)-N-[5-Bromo-2-(4-methyl­anilino)-3H-indol-3-yl­idene]-4-methyl­aniline oxide

The crystal structure of the title compound, C22H18BrN3O, is stabilized by π–π contacts [centroid–centroid distance = 3.476 (2) Å] between five-membered rings as well as inter­molecular C—H⋯O and C—H⋯N hydrogen bonds. An intra­molecular N—H⋯O hydrogen bond occurs. The benzene rings make a dihedral angle of 59.89 (8)°. The dihedral angles between the fused ring systemand the two benzene rings are 3.46 (7) and 61.97 (7)°

Clinical Outcomes After Continuous Intracorneal Ring implantation in Post-LASIK Ectasia: (Long-Term Follow-up)

Purpose: The aim of the present study was to evaluate the clinical outcomes after implantation of MyoRing in patients with ectasia secondary to LASIK. Patients and Methods: This study was a retrospective, consecutive, nonrandomized interventional case series. The MyoRing was implanted after creation of a stromal pocket using a PocketMaker microkeratome (Dioptex, GmBH, Linz, Austria) in 6 eyes of 6 patients with ectasia secondary to LASIK. Uncorrected distance visual acuity, corrected distance visual acuity, sphere, cylinder and keratometric changes were reported after a 3 year follow-up period. Results: Uncorrected distance visual acuity and corrected distance visual acuity were improved in 5 and 3 patients respectively. One patient showed decreased UDVA after 3 years and in 3 patients the corrected distance visual acuity decreased at the last visit compared to the preoperative reading. Maximum keratometry, sphere and cylinder were improved from preoperative values in 4, 2 and 5 patients respectively. Conclusion: Because of the mixed results in our small group of patients, it seems that MyoRing implantation using mechanical dissection is not a very effective method for treatment of patients with post LASIK ectasia. However, large comparative multicenter studies are recommended to further verify these results.Keywords: Ectasia, Cornea, LASIK, Corneal ring, Iran

Safety and Efficacy of Intraocular Phakic Contact Lens Implantation in Keratoconus Patients

Purpose: To evaluate the safety and efficacy of toric implantable phakic contact lens (IPCL) implantation in the treatment of patients with keratoconus.Patients and Methods: We included 17 eyes from 10 consecutive keratoconus patients who underwent toric IPCL implantation (IPCL V.2, Care Group Sight Solutions, India) in this study. The primary measures were uncorrected distance visual acuity (UCVA), best corrected distance visual acuity (BCVA), sphere, astigmatism, and intraocular pressure (IOP). These parameters were assessed preoperatively and at 1, 3, and 6 months postoperatively. Intraoperative and postoperative complications were also evaluated.Results: The mean age of the patients entering the study was 36 ± 8.8 years. The preoperative BCVA was 0.75 ± 0.21 diopter, improving to 0.86 ± 0.11 diopter postoperatively (P = 0.017). The mean UCVA improved significantly from a preoperative measurement of 0.09 ± 0.11 diopter to 0.78 ± 0.15 diopter postoperatively (P &lt; 0.001). The mean spherical equivalent (SE) showed an enhancement from -6.8 ± 2.1 diopters preoperatively to -0.7 ± 0.3 diopters at the postoperative assessment (P &lt; 0.001). The mean IOP increased from 15.3 mmHg to 16.2 mmHg (P = 0.007) which was statistically significant but clinically insignificant. Additionally, none of the patients experienced postoperative complications such as endophthalmitis, uveitis, IPCL rotation, cataracts, or cystoid macular edema (CME) within the six months following the procedure.Conclusion: The implantation of IPCL in patients with keratoconus appears to be safe and effective. However, further studies with longer follow-ups and larger sample sizes are recommended to validate these findings

Herbal-Based Drugs for Dry Eye; Treatment and Adverse Reactions

Dry eye syndrome is one of the most common types of eye diseases. Due to the significant prevalence of the disease, there is an important need for treatment of dry eye in a simple but efficient way. Artificial tears are the most common agents used for treating dry eye but are not very useful. In recent years, the use of herbal remedies has attracted much attention,because the process of producing most herbal remedies is simple, inexpensive and has fewer side effects. In many clinical studies, the potential interactions between medicines and herbs have been demonstrated. According to reports, some herbal products have the potential to be used for the treatment of dry eye while the use of certain products can lead to this syndrome. In this review, we have listed some of the herbal drugs and components which can prevent or treat the dry eye or cause it

Low Iris and Anterior Chamber Volume Associated with Deepening after Laser Peripheral Iridotomy in Primary Angle Closure Suspects

Purpose: To evaluate the association between baseline ocular variables and the opening of the anterior chamber angle by laser peripheral iridotomy (LPI) in primary angle closure suspects (PACS) using a new Fourier-domain swept-source anterior segment optical coherence tomography (FD-ASOCT). Method: Sixty-six PACS eyes of 41 individuals were included in this prospective interventional case series. An FD-ASOCT (Casia SS-1000 OCT; Tomey, Nagoya, Japan) was used to measure biometric baseline variables and at one month after the LPI. Paired t-test was used to compare the difference between pre-and post-LPI measurements. Multivariate regression analysis was used to test for an association between baseline iris thickness and volume, anterior chamber depth and volume, and lens vault with a widening of the angle after an LPI. Results: The mean age of participants was 58.6 ± 8.7 years, 682% of whom were female. The angle opening distance, recess area and trabecular iris surface area at 500 microns increased by 48 to 73% (all p<0.001). Lens vault and iris volume did not change. A low anterior chamber volume and low iris volume were associated with angle greater deepening by LPI. Conclusion: Eyes with a shallow anterior chamber and thinner irises are more likely to experience angle opening from an LPI