The utility of contact lens-assisted corneal cross-linking (CACXL) in progressive keratoconus patients with thin corneas

Purpose To evaluate efficacy and safety of contact lens-assisted corneal cross-linking (CACXL) among progressive keratoconus patients with thin corneas. Setting Private eye hospital Design Cross-sectional study Methods Thirty-six eyes of 36 consecutive patients with progressive keratoconus and thinnest corneal thickness of 380–400 µm after epithelium removal were included. CACXL was performed based on use of a dextran-free isotonic (>0.1%) riboflavin solution with hydroxypropyl methylcellulose (HPMC, 1.1%) after epithelial removal and placement of a riboflavin-soaked contact lens without an ultraviolet filter on the cornea and ultraviolet irradiance. Data on best distance corrected (CDVA) and uncorrected (UDVA) visual acuity, manifest sphere (D), manifest cylinder (D), K1 (D), K2 (D), mean keratometry (D) and Kmax (D) values, endothelial cell count and mean depth of demarcation line were recorded preoperatively and at the postoperative 1-year Results Post-operative 1-year data revealed significant increases in UDVA (0.23 ± 0.15 vs. 0.17 ± 0.13 D, p < 0.001) and CDVA (0.44 ± 0.18 vs. 0.36 ± 0.17 D, p < 0.001) values and a significant reduction in the mean Kmax (from 56 ± 3.3D to 55 ± 3.2 D, p < 0.001), K2 (from 49.7 ± 3.2 D to 49.52 ± 3.11 D, p = 0.049), manifest sphere (from −1.93 ± 2.21 D to −1.55 ± 2.02 D, p = 0.001) and manifest cylinder (from −2.83 ± 1.67 D to −2.39 ± 1.36 D, p < 0.001) values along with a similar endothelial cell count. The mean depth of demarcation line was mean 230 (SD17.05, range 200 to 262) at postoperative 1-month. Conclusions Our findings indicate favourable 1-year postoperative outcome of CACXL in progressive keratoconus patients with thin cornea in terms of improved visual acuity and keratectasia status as well as endothelial safety.

A Comparative Study of Two Types of Implantation Surgery Methods for Implantable Collamer Lenses

Purpose. To investigate the effects of two different surgical methods of implantable collamer lens (ICL) implantation on the operation time, visual outcomes, corneal endothelial cell count, and intraocular pressure (IOP). Methods. This was a contralateral eye comparison study, a total of 192 eyes from 96 patients were included, and the two eyes from the same patient were randomly assigned to two groups (group 1 and group 2, with 96 eyes in each group). In group 1, after making the corneal incision, ophthalmic viscosurgical devices (OVDs) were first injected into the anterior chamber followed by ICL implantation. In group 2, the ICL was first implanted into the anterior chamber followed by OVDs injection. The operation time, uncorrected distance visual acuity, corrected distance visual acuity, spherical equivalent, corneal endothelial cell count, and IOP were recorded and analyzed. Results. The operative time in group 1 was significantly longer than that in group 2 ( P = 0.002 < 0.05). There were significant differences between IOP measured 2 hours following surgery of the two groups ( P = 0.026 < 0.05), Furthermore, the rate of IOP change 2 hours following the operation was significantly higher in group 1 than in group 2 ( P = 0.019 < 0.05). There were significant differences in the anterior chamber angle 2 hours after surgery compared with that before surgery in both groups ( P = 0.014 < 0.05 and P = 0.029 < 0.05, respectively). No significant differences were observed in the other parameters measured (all P > 0.05). Conclusion. The two ICL implantation methods had similar clinical outcomes and effects on the corneal endothelial cell count. Additionally, the implantation of an intraocular lens prior to injecting OVDs reduces the operation time and lowers the rate of IOP rise in the early postoperative period, making it safe and effective for ICL implantation.

A comparative study of divide and conquer, stop and chop and phaco chop techniques of nucleotomy in phacoemulsification

Phacoemulsification is a variant of extracapsular cataract extraction surgery which is the gold standard treatment modality for cataract surgery nowadays. The common nucleotomy techniques of phacoemulsification are divide and conquer, stop and chop and phaco chop.Aim of this studyto compare different techniques of nucleotomy during phacoemulsification with respect to corneal endothelial cell loss, central corneal thickness (CCT) and comment on their merits and demerits. 60 patients undergoing cataract surgery by phacoemulsification were randomly divided into three groups of 20 each (Group A, B and C) who underwent nucleotomy by divide and conquer, stop and chop and phaco chop technique respectively. The preoperative endothelial cell density and central corneal thickness were recorded using Topcon SP3000P non-contrast specular microscope. All patients were followed up at 1, 4 and 12week after surgery and evaluated for vision, slit lamp examination, endothelial cell count and central corneal thickness.The age group of patients studied was 50-80 years, where maximum number of patients were in 51-60 years age group. Out of 60 patients, most common morphological type of cataract was nuclear (40%) cataract followed by cortico-nuclear (36.67%) cataract. After 1 week of surgery, drop in endothelial cell density was 7.06% in Group A, 6.49% in Group B and 6.84% in Group C patients. A further slight decrease in endothelial cell count was recorded during 4week and on final follow up visit at 12 weeks after cataract surgery, there was an endothelial cell loss of 9.51%, 10.9% and 11% in Group A, B and C respectively. The central corneal thickness at 1postoperative week increased by 2.75%, 2.35% and 2.20% in group A, B and C respectively. Further evaluation of CCT at 4and 12 week after surgery showed the values to be almost same as preoperative values. The rate of complications, which mainly included postoperative keratitis, mild anterior uveitis and cystoid macular edema, were found to be almost the same in all the three study groups.All the three nucleotomy techniques of phacoemulsification i.e divide and conquer, stop and chop and phaco chop are equally efficacious in terms of CCT changes, endothelial cell loss and complications rate in the hands of an experienced surgeon.

Effect of donor and host factors on corneal graft transparency

Objective: To study the correlation between donor factors and recipients' factors on graft clarity.Materials and methods: The study comprised 30 cases of Keratoplasty surgery with a follow up of6 months. All donor corneas were evaluated by Konan specular microscope for endothelial cellcount; details of the donor like age, cause of death were noted. The patients were divided into twogroups, Group 1 had graft failure, and Group 2 had clear corneas. Observation and Result: Therewere 12 patients in group 1 and 18 patients in group 2 with six months of follow up. The meanendothelial cell count in group 1 was 1942.3/mm2, and group 2 was 2334.8/mm2. There is asignificant difference in the mean endothelial cell count between the two groups. On analysing theindication for Keratoplasty in two groups, the outcome was best for the corneal opacity group duringworst for the graft failure group. Conclusion: Donor endothelial cell count significantly influencedgraft outcome; rest donor factors (age, death enucleation interval, enucleation surgery interval)don't affect graft survival. Indication for Keratoplasty is a significant predictor of graft survival.

Effect of Hydroxypropylmethylcellulose versus Sodium Hyaluronate on corneal endothelial cell count in patients undergoing cataract surgery by phacoemulsification

Objective: To compare the effect of Hydroxypropyl methylcellulose versus Sodium Hyaluronate on corneal endothelial cell count in patients undergoing cataract surgery by phacoemulsification. Design: It was a randomized clinical trial. Study Settings: This study was conducted at the Eye Unit III, Mayo Hospital / KEMU, Lahore over 12 months period from June 2014 to May 2015. Hypothesis: There is a significant difference in protective effect on corneal endothelial cell loss with dispersive (Hydroxypropyl methylcellulose) viscoelastic agent as compared to cohesive (sodium hyaluronate) viscoelastic agent used during phacoemulsification with intraocular lens for the treatment of cataract. Material and Methods: Total 80 patients from both the genders aged between 40-70 years with cataract undergoing phacoemulsification surgery were involved in this study. Two equal treatment groups were made by random allocation. Patients in Group-A (n=40) received Hydroxypropyl methylcellulose as viscoelastic agent while patients in Group-B (n=40) received treatment with Sodium Hyaluronate. Surgery was carried out by phacoemulsification technique and follow-up was done at first week, 1st month and 3rd month post-operatively. Data was collected in terms of endothelial cell count by noncontact specular microscope. Results: Patients age was in the range of 40 to 70 years with a mean of 57.26 ± 8.00 years. There were 31 (38.75%) females and 49 (61.25%) male patients with a female to male ratio of 1.6:1. Both the groups had no statistically significant difference in the mean corneal cell count before surgery (2839.67±368.71 cells/mm2 vs. 2801.36 ± 332.52 cells/mm2; p-value= 06.27). Post-operative mean corneal cell count at 1 week, 1 month and 3 months was significantly higher in patients in Group-A compared to Group-B. Similarly, significant difference was noted across various subgroups of both the groups on the basis of patient’s age and gender. Conclusion: This study concluded that there is less corneal endothelial cell loss with dispersive Hydroxypropyl methylcellulose viscoelastic agent as compared to cohesive sodium hyaluronate viscoelastic agent used during phacoemulsification surgery with intraocular lens implant for the treatment of cataract. Keywords: Cataract, phacoemulsification, viscoelastic agents, corneal, endothelial cell.

Structural Changes in Thin Keratoconic Corneas Following Crosslinking with Hypotonic Riboflavin: Findings on In Vivo Confocal Microscopy

Purpose: To report structural changes observable in in vivo confocal microscopy (IVCM) in keratoconic corneas <400 μm treated with hypotonic riboflavin and collagen crosslinking (CXL). Method: Ten eyes of ten patients with progressive keratoconus and corneal thickness between 350 and 399 μm underwent CXL with hypotonic riboflavin. IVCM was performed preoperatively and at one month, three months, and six months after the procedure. Results: IVCM analysis one month postoperatively showed complete absence of the subepithelial nerve plexus with gradual regeneration over six months in 8 of the 10 eyes, and poor regeneration in the remaining 2 eyes. The anterior stroma showed extracellular lacunae and hyper-reflective cytoplasm in a honeycomb appearance signifying edema at one month which gradually decreased over six months post CXL. Stromal keratocyte apoptosis was evident in the anterior stroma in all cases and extended to the posterior stroma in four eyes with gradual regeneration evident at three and six months. The specular endothelial count decreased by 8% (P = 0.005) post-CXL, but no corneas developed clinical signs of endothelial trauma. Conclusion: IVCM analysis of thin corneas after hypotonic CXL showed posterior corneal structural changes. Posterior stromal changes were accompanied by a decrease in the endothelial cell count. This case series was a preliminary feasibility study that might necessitate conducting a well-designed controlled study.

Standardized Flanged Intrascleral Intraocular Lens Fixation with the Double-Needle Technique for Cataract Luxation in the Vitreous Chamber during Phacoemulsification

Purpose. To assess the visual and refractive outcome of immediate intraoperative vitrectomy and intrascleral intraocular lens implantation using a “standardized” sutureless Yamane technique during cataract luxation in the vitreous chamber as a complication of phacoemulsification. Design. A prospective, interventional, consecutive case series. Materials and Methods. Twelve patients underwent vitrectomy and intrascleral intraocular lens fixation using a standardized Yamane technique as the primary procedure during complicated phacoemulsification. Patients were evaluated preoperatively and 6 months postoperatively for best-corrected distance visual acuity, correspondence to the preoperative refractive target in the spherical equivalent, endothelial cell count, and complications. Results. Mean preoperative best-corrected visual acuity was 1.16 ± 0.3 logarithm of the minimum angle of resolution (logMAR), the endothelial cell count was 1910.5 ± 297.64, and target refraction at baseline was −0.197 ± 0.087. Postoperatively, best-corrected visual acuity was significantly improved; the mean value was 0.05 logMAR ± 0.06. Mean baseline target refraction in the spherical equivalent was −0.20 ± −0.09 (range: −0.08 to −0.37), and mean final refraction was −0.44 ± −0.14 (range: −0.25 to −0.75) with no significant difference p = 0.87 . No complication was registered intra- and postoperatively. Conclusion. Standardization of the Yamane technique seemed a valuable option for patients who had complicated phacoemulsification to achieve a predictable refractive outcome. Synopsis. The predictable refractive outcome could be achieved with the immediate standardized Yamane technique in patients with intraoperative cataract luxation in the vitreous chamber during phacoemulsification.

Clinical performance of presbyopia correction with a multifocal corneoscleral lens

AIM: To assess the clinical performance of a multifocal corneoscleral lens for the presbyopia correction. METHODS: A prospective clinical trial of the Onefit™ A multifocal corneoscleral lens was conducted with 40 participants with presbyopia. At 4wk of continuous wear of the corneoscleral lens, changes in the distance, intermediate, and near visual acuity (VA) were evaluated. The safety of the corneoscleral lens, central corneal thickness (CCT), corneal endothelial cell count, binocular stereopsis, tear film break-up time (BUT), corneal staining, corneal edema, corneal neovascularization (NV), and conjunctival hyperemia were examined. In addition, a subjective questionnaire addressing satisfaction (rated from 1 to 5 points) and discomfort (rated from 1 to 5 points) was administered. RESULTS: Forty participants were enrolled in this study. Six participants were excluded because of poor compliance with lens fitting (n=2) and loss to follow-up (n=4). The mean age of the participants was 53.0±4.9y. At 4wk of continuous wear of the corneoscleral lens, the best corrected far, intermediate, and near VA was 0.08±0.11, 0.10±0.12, and 0.10±0.12 logMAR, respectively. These results were significant improvements over the baseline uncorrected VA (far: P=0.004; intermediate: P=0.004; near: P=0.002). CCT, corneal endothelial cell count, binocular stereopsis, BUT, corneal staining, corneal edema, corneal NV, and conjunctival hyperemia were not significantly different between baseline and after corneoscleral lens use. The average satisfaction scores for fit sensation; corrected far, intermediate, and near VA; and ease of handling were 4.1, 3.4, 3.6, 3.5, and 3.4, respectively. The average discomfort scores for dryness, irritation, foreign body sensation, redness, fogging, and halo were 1.7, 1.8, 1.5, 1.7, 1.7, and 1.3, respectively. CONCLUSION: Far, intermediate, and near VA are improved in presbyopic patients with the multifocal corneoscleral lens compared to uncorrected baseline VA, without adverse ocular effects. This evidence supports the safety and effectiveness of presbyopia correction with multifocal corneoscleral lenses.

The kebab technique uses a bipolar pencil to retrieve a dropped nucleus of the lens via a small incision

We developed a new method to retrieve a dropped nucleus of the lens via a small incision using bipolar pencils, the kebab technique, to solve the lack of small-gauge fragmatomes, and the expense and toxicity of perfluorocarbon liquids (PFCL). A total of 8 eyes in 6 patients underwent this technique and were reviewed. After vitrectomy, the dropped nucleus of the lens was lifted from the retina by adhesion with a bipolar pencil, and phacoemulsification was performed while rotating the lens. The outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP), and corneal endothelial cell density before and after surgery. Surgical indications included zonular weakness, trauma, acute angle closure attack, and phacolytic glaucoma. At 1 month, BCVA improved from a mean (standard deviation, SD) 1.67 logMAR (0.90) to 1.14 logMAR (1.01). The mean preoperative IOP was 24.5 (16.8) mmHg and postoperative IOP was 11.0 (2.8) mmHg. The mean preoperative corneal endothelial cell count was 2600 (322) cells/mm2 (one eye was unmeasurable) and postoperative corneal endothelial cell count was 2387 (431) cells/mm2. There were no postoperative complications. The retrieval of a dropped nucleus of the lens using a bipolar pencil enables small incisions without using PFCL.

The Kebab Technique: Using a Bipolar Pencil to Retrieve a Dropped Nucleus via a Small Incision

We developed a new method to retrieve a dropped nucleus via a small incision using bipolar pencils, the kebab technique, to solve the lack of small-gauge fragmatomes, and the expense and toxicity of perfluorocarbon liquids (PFCL). A total of 8 eyes in 6 patients underwent this technique and were reviewed. After vitrectomy, the dropped nucleus was lifted from the retina by adhesion with a bipolar pencil, and phacoemulsification was performed while rotating the lens. The outcome measures were best-corrected visual acuity (BCVA), intraocular pressure (IOP), and corneal endothelial cell density before and after surgery. Surgical indications included zonular weakness, trauma, acute angle closure attack, and phacolytic glaucoma. At 1 month, BCVA improved from a mean ± SD 1.67 logMAR (± 0.90) to 1.14 logMAR (± 1.01). The mean preoperative intraocular pressure (IOP) was 24.5 (± 16.8) mmHg and postoperative IOP was 11.0 (± 2.8) mmHg. The mean preoperative corneal endothelial cell count was 2600 (322) cells/mm2 (one eye was unmeasurable) and postoperative corneal endothelial cell count was 2387 (± 431) cells/ mm2. There were no postoperative complications. The retrieval of a dropped nucleus using a bipolar pencil enables small incisions without using PFCL.