Best Contact Lens-corrected Visual Acuity Research Articles

Femtosecond laser-assisted Bowman layer transplantation for advanced keratoconus.

To assess the technical feasibility and outcomes of femtosecond laser-assisted Bowman layer transplantation (FLABOLT) in stabilizing progressive, advanced keratoconus, which is ineligible for corneal crosslinking. This single-center retrospective study included 50 eyes of 49 patients with progressive advanced keratoconus, ineligible for corneal crosslinking, that underwent FLABOLT with both the donor graft and recipient mid-stromal pocket using a femtosecond laser. The mean follow-up was 13.2 ± 4.9 months (range 7-35 months). Donor graft preparation and accurate dissection of the recipient mid-stromal pocket were successful in 96% and 100% of cases, respectively. The mean maximum keratometry decreased by 1.93 D at 6 months after surgery and there was no change in the mean preoperative best contact lens-corrected visual acuity (BCLVA). Three eyes developed hydrops postoperatively and recovered after clinical treatment. One eye that achieved useful BCLVA postoperatively, worsened 2 years after the surgery due to progressive corneal scarring and required corneal transplantation for visual rehabilitation. Preoperative corneal scarring was a risk factor for BCLVA loss. All other eyes remained stable (92%), and no other procedure was required until the last follow-up. In this series, FLABOLT was successfully performed as an alternative to stabilize advanced progressive keratoconus. This technique is highly reproducible for graft preparation and recipient pocket dissection when assisted by femtosecond laser. Despite promising initial results, more studies with longer follow-up periods are needed to evaluate the effectiveness of FLABOLT in stabilizing advanced progressive keratoconus.

Intrastromal descemet membrane transplantation in eyes with advanced keratoconus

Background. To report the outcomes of intrastromal Descemet membrane (DM) transplantation in corneas with advanced keratoconus.
 Materials and methods. Three eyes of 3 patients presented with advanced, progressive keratoconus. None of the eyes had prior UV-crosslinking or any other ocular surgery performed. All eyes had a donor DM implanted into a mid-stromal pocket under local anesthesia, and clinical outcomes were evaluated at 12 months after surgery.
 Results. To the best of our knowledge, this is the first report of DM transplantation performed in cases of advanced keratoconus. At 12 months after surgery, the DM graft was well positioned and barely visible within the recipient stroma, and all corneas were clear. None of the eyes showed signs of keratoconus progression throughout the follow-up period. No significant changes were observed in uncorrected (UCVA) and best contact lens corrected visual acuity (BCLCVA), central endothelial cell density (ECD), corneal thinnest point (CTP) pachymetry, and maximum keratometry values (SimK and Kmax). No early or late postoperative complications were observed.
 Conclusions. Intrastromal DM transplantation may potentially be an alternative to intrastromal Bowman layer transplantation in eyes with advanced keratoconus, to postpone deep anterior lamellar or penetrating keratoplasty.

Bowman Layer Onlay Transplantation to Manage Herpes Corneal Scar

To introduce the concept of using a Bowman layer (BL) onlay graft to manage superficial herpetic corneal scarring and to describe the clinical outcomes of the first 2 cases undergoing this procedure. Two patients with a quiescent superficial corneal scar after herpes (varicella zoster virus [n = 1] and herpes simplex virus [n = 1]) keratitis underwent BL onlay transplantation. After the removal of the host epithelium and limited superficial keratectomy, an isolated BL graft was placed onto the host corneal surface. The cornea was then covered with an amniotic membrane and a bandage contact lens. Best spectacle-corrected visual acuity (VA) and/or best contact lens-corrected VA (BCLVA), biomicroscopy, corneal tomography, and anterior segment optical coherence tomography were recorded at 1 week, 1 month, and 3, 6, 9, 12, and 18 months postoperatively. In both cases, the surgical and postoperative courses were uneventful. An improvement of the corneal clarity was observed at biomicroscopy, and no varicella zoster virus/herpes simplex virus reactivation occurred throughout the follow-up period. Biomicroscopy, Scheimpflug imaging, and anterior segment optical coherence tomography showed a completely epithelialized and well-integrated graft postoperatively. In case 1, BCLVA with a scleral lens improved from 20/100 (0.1) preoperatively to 20/32 (0.6) postoperatively. For case 2, no preoperative BCLVA was available, but a BCLVA of 20/36 (0.55) was achieved after the procedure. A BL onlay graft may be a feasible surgical procedure, which may have the potential to reduce superficial corneal scarring and/or anterior corneal irregularities without resorting to deeper keratoplasty in these complex cases.

Mini-Scleral Lenses for Correction of Refractive Errors After Radial Keratotomy.

To evaluate the factors affecting clinical outcomes of correcting cumulative refractive errors or irregular astigmatism after radial keratotomy (RK) using mini-scleral lenses. We retrospectively analyzed 36 eyes receiving mini-scleral lenses after RK from July 2011 to June 2016. Analyses included age, refractive errors, best spectacle-corrected visual acuity (BSCVA), best contact lens-corrected visual acuity (BCLCVA), topographic indices, RK treatment zone diameter (TZD), power difference (PrD) within the RK treatment zone, and decentration distance (DD) of the RK treatment zone center. An increase of three lines or more of Snellen visual acuity was considered a successful fitting. Of the eyes fitted with mini-scleral lenses, the BCLCVA (logarithm of the minimum angle of resolution [logMAR] 0.19±0.22) was significantly better than the BSCVA (logMAR 0.47±0.30). Twenty-three patients (64%) had a successful fitting. There was no statistically significant difference between successful and unsuccessful fittings with regard to age, prefitting refractive error, BSCVA, corneal astigmatism, simulated steep/flat K values, surface regularity index, TZD, or PrD. However, successful fittings had better centration of treatment zones with an average DD of 0.54±0.44 mm compared with a DD of 0.92±0.53 mm in the unsuccessfully fitted eyes. In addition, our case series showed that there was a negative impact on fitting outcomes in the presence of small central clear zones resulting from central incisions or scars. Although decentration of the RK treatment zone and small central clear zones were related to less optimal fitting results, mini-scleral lenses are a feasible option to correct cumulative refractive errors and irregular astigmatism in post-RK patients.

Clinical Performance of Toris K Contact Lens in Patients with Moderate to Advanced Keratoconus: A Real Life Retrospective Analysis.

Objectives. To evaluate the visual performance of Toris K soft contact lenses in patients with moderate-to-advanced keratoconus and also to compare the results according to cone types, cone location, and severity of keratoconus. Materials and Methods. Sixty eyes of 40 participants were included in this retrospective study. Uncorrected visual acuity (UCVA), best-spectacle corrected visual acuity (BCVA), best-contact lens corrected visual acuity (BCLCVA), and comfort rating via visual analogue scales (VAS) were measured. Results. The mean age was 27.3 ± 8.6 years (range: 18 to 54). The mean logMAR UCVA, BCVA, and BCLCVA were 0.85 ± 0.38 (range: 0.30–1.30), 0.47 ± 0.27 (range: 0.10–1.30), and 0.16 ± 0.20 (range: 0–1.00). There were significant increases in visual acuities with contact lenses (p < .05). BCLCVA was significantly better in oval type than globus type (p = .022). UCVA and BCLCVA were significantly better in moderate keratoconus group (p = .015, p = .018). The mean line gain in Snellen was 3.6 ± 1.8 lines (range: 0–7 lines). The mean line gain was higher in central cone group than paracentral cone group and oval group than globus group (p = .014, p = .045). The mean VAS score was 8.14 ± 1.88 (range: 6–10). Conclusions. Toris K can improve visual acuity of patients with keratoconus. Toris K is successful even in the moderate and advanced form of the disease.

Deep layers of the cornea and basic research in Spain

To evaluate the clinical outcome of mid-stromal isolated Bowman layer transplantation, a new surgical technique to reduce and stabilize ectasia in eyes with advanced keratoconus, to postpone penetrating keratoplasty or deep anterior lamellar keratoplasty, and to enable continued daily contact lens wear.Prospective, nonrandomized cohort study at a tertiary referral center.Twenty-two eyes of 19 patients with progressive, advanced keratoconus not eligible for ultraviolet cross-linking.The mid-stroma was manually dissected and an isolated donor Bowman layer was positioned within the stromal pocket.Before and up to 36 months after surgery (mean follow-up, 21±7 months), best spectacle-corrected visual acuity (BSCVA), best contact lens–corrected visual acuity (BCLVA), Scheimpflug-based corneal tomography measurements, endothelial cell density, biomicroscopy, refraction, and intraoperative and postoperative complications were recorded.Two surgeries were complicated by an intraoperative perforation of Descemet membrane; no other intraoperative or postoperative complications were observed. Maximum keratometry decreased on average from 77.2±6.2 diopters (D) to 69.2±3.7 D (P < 0.001) at 1 month after surgery and remained stable thereafter (P ≥ 0.072). Mean BSCVA improved from 1.27±0.44 logarithm of the minimum angle of resolution units before surgery to 0.90±0.30 logarithm of the minimum angle of resolution units 12 months after surgery (P < 0.001), whereas BCLVA remained stable (P = 0.105). Mean thinnest-point pachymetry increased from 332±59 μm before surgery to 360±50 μm at the latest follow-up (P = 0.012), and no change in endothelial cell density was found (P = 0.355).With isolated Bowman layer transplantation, reduction and stabilization of corneal ectasia was achieved in eyes with progressive, advanced keratoconus. Given the low risk for complications, the procedure may be performed to postpone penetrating or deep anterior lamellar keratoplasty.

Bowman Layer Transplantation to Reduce and Stabilize Progressive, Advanced Keratoconus

To evaluate the clinical outcome of mid-stromal isolated Bowman layer transplantation, a new surgical technique to reduce and stabilize ectasia in eyes with advanced keratoconus, to postpone penetrating keratoplasty or deep anterior lamellar keratoplasty, and to enable continued daily contact lens wear. Prospective, nonrandomized cohort study at a tertiary referral center. Twenty-two eyes of 19 patients with progressive, advanced keratoconus not eligible for ultraviolet cross-linking. The mid-stroma was manually dissected and an isolated donor Bowman layer was positioned within the stromal pocket. Before and up to 36 months after surgery (mean follow-up, 21±7 months), best spectacle-corrected visual acuity (BSCVA), best contact lens-corrected visual acuity (BCLVA), Scheimpflug-based corneal tomography measurements, endothelial cell density, biomicroscopy, refraction, and intraoperative and postoperative complications were recorded. Two surgeries were complicated by an intraoperative perforation of Descemet membrane; no other intraoperative or postoperative complications were observed. Maximum keratometry decreased on average from 77.2±6.2 diopters (D) to 69.2±3.7 D (P < 0.001) at 1 month after surgery and remained stable thereafter (P ≥ 0.072). Mean BSCVA improved from 1.27±0.44 logarithm of the minimum angle of resolution units before surgery to 0.90±0.30 logarithm of the minimum angle of resolution units 12 months after surgery (P < 0.001), whereas BCLVA remained stable (P = 0.105). Mean thinnest-point pachymetry increased from 332±59 μm before surgery to 360±50 μm at the latest follow-up (P = 0.012), and no change in endothelial cell density was found (P = 0.355). With isolated Bowman layer transplantation, reduction and stabilization of corneal ectasia was achieved in eyes with progressive, advanced keratoconus. Given the low risk for complications, the procedure may be performed to postpone penetrating or deep anterior lamellar keratoplasty.

Rose-K versus soper contact lens in keratoconus: A randomized comparative trial

Purpose:To perform a comparative evaluation of the efficacy and acceptability of Rose-K and Soper contact lenses in Keratoconus.Setting:Dr. Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi.Materials and Methods:A randomized comparative clinical trial was performed in keratoconic eyes fitted with Rose-K (Rose-K group) and Soper (Soper group) contact lenses. Patients data were evaluated for best spectacle corrected visual acuity, best contact lens corrected visual acuity (BCLCVA), corneal topography, glare acuity, contrast sensitivity, tear function tests and specular microscopy. Patients were also asked to complete a self-reported comfort questionnaire at each visit.Results:Sixty eyes were randomized to the Rose-K and Soper groups. The two groups were comparable in all the baseline parameters. There was a statistically significant improvement in BCLCVA in both groups at 3 months (P < 0.01, both groups). The difference between in BCLCVA in both groups was not statistically significant. In both groups, there was a significant improvement in the comfort score at 3 months compared to baseline (P < 0.05, both group). The Rose-K group had statistically significantly better scores at 1 and 3 months compared with the Soper group (P = 0.006 and P < 0.001 respectively). Both groups were associated with a significant (P < 0.01), but comparable improvement in glare acuity at 3 months. There was a significant improvement in contrast sensitivity at 3 months in both groups (P < 0.01); the Rose-K group was significantly better than the Soper group at 1 and 3 months (P = 0.001 and 0.002 respectively). The mean number of trial lenses required for fitting Rose-K lens (2.00 ± 0.59) was significantly lower than the Soper lens (3.43 ± 0.82; P < 0.001).Conclusion:Both the contact lens designs provide an equal improvement in visual acuity in patients with Keratoconus. However, Rose-K contact lens provides greater comfort, better quality of vision and requires less chair time compared with the Soper lens and hence may possibly have a greater acceptability.

Intacs for Keratoconus and Post-LASIK Ectasia

To evaluate the efficacy of intracorneal ring segments to treat keratoconus and post-laser in situ keratomileusis (LASIK) keratectasia implanted by using either mechanical dissection or a femtosecond laser. Thirty-three eyes of 29 patients had intracorneal ring segments implanted by using mechanical dissection (17 eyes) or a femtosecond laser (16 eyes). Mean follow-up was 10.3 months. Parameters assessed before and after surgery included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent (MRSE), refractive cylinder (RC), best contact lens-corrected visual acuity (BCLVA), and contact lens tolerance. Statistically significant changes occurred for all parameters when we analyzed all 33 eyes as 1 group. Mean UCVA LogMar values improved from 1.0 +/- 0.3 (20/200) to 0.6 +/- 0.4 (20/80) (P < 0.0005). Mean BSCVA changed from 0.3 +/- 0.2 (20/40) to 0.2 +/- 0.2 (20/30) (10%; P < 0.05), and MRSE from -9 +/- 4 to -7 +/- 4 D (P < 0.05; 20%). There was a decrease of 0.5 D or more of RC in 62% of eyes. BCLVA improved from 0.2 +/- 0.2 (20/30) to 0.1 +/- 0.1 (20/25) after surgery (P < 0.02). Contact lens tolerance improved in 81% of eyes. There was no statistically significant difference in outcomes between mechanical dissection and femtosecond laser-assisted techniques. However, although statistical power was adequate to detect changes in clinical parameters as a result of surgery, it was not sufficient to conclusively show such differences between surgical techniques. For mild to moderate cases of keratoconus and post-LASIK keratectasia, the use of a femtosecond laser for Intacs channel creation seems as effective as mechanical dissection. Future studies are warranted to further evaluate channel creation by a femtosecond laser.

Microkeratome-Assisted Lamellar Keratoplasty for the Surgical Treatment of Keratoconus

To evaluate the visual and refractive results of microkeratome-assisted lamellar keratoplasty (LK) performed on keratoconus patients intolerant to spectacles and contact lenses. Prospective, noncomparative, interventional study. A microkeratome-assisted LK procedure was performed on 50 eyes of 50 keratoconus patients. All patients were spectacle and contact lens intolerant. All patients included in this study underwent a standard surgical procedure involving removal of a lamella (9 mm in diameter cut with the 250-microm microkeratome head) from the recipient cornea by means of a hand-driven microkeratome and suturing of a donor lamella (0.5 mm smaller in diameter than the removed corneal lamella, cut with the 350-microm microkeratome head) obtained from a cornea mounted on an artificial anterior chamber. Each patient was examined preoperatively and at different postoperative times (1 and 6 months and 1, 2, 3, and 4 years). Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), 1-year best contact lens-corrected visual acuity (BCLCVA), refraction, and computerized analysis of corneal topography. After suture removal was completed, both UCVA and best-corrected visual acuity were significantly improved over properative values at all examination times. One year postoperatively, when follow-up was still available for all patients, UCVA was better than 20/200 in 8 of 50 (16%) patients and BSCVA was > or =20/40 in 44 of 50 (88%) patients, whereas BCLCVA was > or =20/40 in all 50 patients. Refractive astigmatism within 4 diopters was seen in 43 of 50 (86%) patients. Corneal topographic patterns were classified as regularly astigmatic in 39 of 50 (78%) patients. The 1-year values did not change substantially at later postoperative examination times. Complications included preparation of donor grafts of poor quality that needed to be discarded (8 cases [16%]), irregular astigmatism of various degrees (11 cases [22%]), high-degree astigmatism requiring secondary intervention (6 cases [12%]), epithelial interface ingrowth (1 case [2%]), and cataract formation (1 case [2%]). Microkeratome-assisted LK can be performed on corneas with moderate to advanced keratoconus with a minimal corneal thickness of >380 microm. The procedure is relatively simple, may be standardized in most of its parts, and does not involve time-consuming maneuvers. All complications recorded did not threaten vision and were dealt with successfully. Our results indicate that microkeratome-assisted LK is as efficacious as conventional penetrating keratoplasty for the surgical treatment of keratoconus. However, the time necessary to achieve stable results is considerably shorter.

Feasibility of contact lens fitting on keratoconus patients with INTACS inserts

Purpose: To demonstrate the feasibility of contact lens fitting in keratoconus patients with INTACS inserts. Methods: A chart review was conducted of all patients with bilateral keratoconus who were treated with INTACS inserts on one eye and who were subsequently referred for contact lens fitting in a university based contact lens practice between April 2000 and April 2002. The study was a retrospective, non-comparative case series. The uncorrected and best spectacle corrected visual acuity (BSCVA) after INTACS implantation surgery, postoperative best contact lens-corrected visual acuity (BCLVA), number of diagnostic contact lenses used, number of contact lenses ordered within a 4-month follow-up period, contact lens complications encountered, final base curves, final lens powers, and final wearing times were determined. Results: Three keratoconic patients meeting the selection criteria were found through the chart review. Prior to surgery, all patients had uncorrected visual acuity (UCVA) of 2.0 logMAR (counting fingers). This improved to a mean of 0.81±0.25 logMAR (20/125-1) after surgery. Mean BSCVA also improved from 0.51±0.30 logMAR (20/60-2) to 0.30±0.16 logMAR (20/40). The mean postoperative best contact lens-corrected visual acuity was 0.02±0.10 logMAR (20/20-1). The number of diagnostic lenses ranged from 1 to 7. The numbers of contact lenses ordered during the 4-month follow up period ranged from 1 to 3. Two eyes were fitted with larger than usual lens designs made of rigid gas-permeable material and one eye was fitted with a toric soft lens. The final lens power ranged from +1.25 to −21.0 D with a mean spherical equivalent of −7.46±11.89 D. Final wearing times ranged from 2.5 to 12.0 h. Conclusion: Fitting contact lenses on keratoconus patients who have INTACS inserts is feasible and has a role in augmenting their vision.