Appropriate Sequence of Combined Intracorneal Ring Implantation and Corneal Collagen Cross-Linking in Keratoconus: A Systematic Review and Meta-Analysis.

PURPOSE: To compare surgical sequences of combined intracorneal ring segment (ICRS) implantation and corneal collagen cross-linking (CXL) in keratoconus and corneal ectasia in terms of visual, refractive, and keratometric outcomes. METHODS: A comprehensive electronic search (in PubMed, Web of Science, Scopus, Embase, and Cochrane Library) was conducted in accordance with the PRISMA statement to find articles on combined ICRS implantation and CXL in keratoconus and corneal ectasia. The search period was from the inception of the database up to April 2017. Eligible articles were categorized into 3 surgical sequences (same day, ICRS first, and CXL first) and assessed qualitatively. Articles with 12 months of follow-up data after combined surgery were included in the meta-analysis. RESULTS: The initial search identified 120 related articles, of which 17 were included in the review after screening. The quality assessment showed that visual, refractive, and keratometric improvement was observed in all studies in all 3 groups of combined surgery. Meta-analysis on 6 studies that reported 12-month follow-up outcomes showed no significant differences between the 3 groups regarding uncorrected and best-corrected visual acuity and cylindrical refractive error. However, results with simultaneous surgery were superior to the CXL-first technique in terms of spherical refractive errors and flat-K (P = 0.011 and P = 0.0001, respectively) and to both CXL first and ICRS first in terms of steep-K (P = 0.002 and P = 0.007, respectively). CONCLUSIONS: Simultaneous ICRS implantation and CXL may provide better outcomes than staged techniques for improving the corneal shape.

Corneal Collagen Cross-Linking in the Treatment of Progressive Keratoconus: A Randomized Controlled Contralateral Eye Study.

BACKGROUND: To assess the short-term efficacy and safety of corneal collagen cross-linking (CXL) in preventing the progression of keratoconus (KCN). MATERIALS AND METHODS: This randomized controlled clinical trial enrolled 26 patients diagnosed with bilateral progressive KCN and were eligible for CXL. In each patient, one eye was randomly selected for treatment, and the contralateral eye served as the control. The patients underwent CXL with riboflavin drops and ultraviolet radiation in the treated eye. One year follow-up data are presented. Postoperatively, patients were assessed for progression of KCN, visual changes, and other findings. The main outcome measures were maximum simulated keratometry (K-max), best spectacle-corrected visual acuity (BSCVA), and average simulated keratometry. P <0.05 was considered as statistically significant. RESULTS: In the treated eyes, the mean K-max values decreased by 0.22 D at 1-year postoperatively and increased by 0.41 D in the control group. This difference was statistically significant (P < 0.001). BSCVA improved slightly (a decrease of 0.13 LogMAR) and decreased slightly in the control group (a 0.01 LogMAR increase). The difference between groups was statistically significant (P = 0.014). There was no decrease in visual acuity attributable to complications of CXL in the treated eyes. At 1-year, the keratometry in 3 (12%) treated eyes increased by more than 0.50 D and were considered cases of failed treatment. CONCLUSION: Preliminary and 1-year results indicate CXL can halt the progression of KCN in most cases without causing serious complications.

Evaluation of the Results of Using Toric IOL in the Cataract Surgery of Keratoconus Patients.

PURPOSE: To evaluate the results of using AcrySof toric intraocular lenses (IOLs) in the cataract surgery of patients with keratoconus (KCN). METHODS: In this study, 23 eyes of 17 patients with KCN who underwent cataract surgery using the toric IOL were evaluated. The amount and axis of the corneal astigmatism were measured by manual keratometry, corneal topography, refractive map of the Pentacam, and equivalent K reading of the Pentacam in all patients. RESULTS: The mean uncorrected visual acuity increased significantly 3 months after the surgery (P<0.01). The mean best-corrected visual acuity was 0.28±0.10 logMAR, 0.51±0.52 logMAR, and 0.83±0.55 logMAR before the surgery and 0.16±0.09 logMAR, 0.18±0.12 logMAR, and 0.35±0.13 logMAR after the surgery in the mild, moderate, and severe KCN groups, respectively (P<0.01). The mean IOL rotation was 2.50±1.18 degrees, 2.50±1.51 degrees, and 2.67±1.15 degrees in the mild, moderate, and severe KCN groups. The lowest mean absolute error was seen in the mild and moderate KCN groups with corneal topography-derived keratometry using the SRK/T formula and in the severe KCN group with corneal topography-derived keratometry and manual keratometry using the SRK/T and SRK II formulas. CONCLUSIONS: The use of toric IOLs resulted in desirable vision and refraction in the cataract surgery of patients with nonprogressive KCN. As for determining the IOL power, it seems that keratometry derived from the 3 mm central zone in the axial map of corneal topography using the SRK/T formula has the lowest error.

Small pupil and cataract surgery.

PURPOSE OF REVIEW: Presence of a small pupil is still considered a major challenge for cataract surgeons. Appropriate mydriasis and maintaining it is of paramount importance to prevent potential serious complications. Recently, more interventions and instruments are available for the cataract surgeons to deal with these challenging cases. The intention of this review is to discuss the preoperative and intraoperative considerations and techniques for cataract surgery in small pupil and related conditions and to discuss new developments in management of small pupil in femtosecond laser-assisted cataract surgery. RECENT FINDINGS: There are new techniques and pharmaceuticals available to cataract surgeons in the setting of small pupil. Intracameral ketorolac may soon be available to maintain mydriasis and to control pain and inflammation. Malyugin ring has been added to pupil expansion rings and has already been used for small pupil in different settings. In femtosecond laser-assisted cataract surgery, presence of a small pupil can now be managed by applying intracameral mydriatics and intraocular devices successfully. SUMMARY: Accurate preoperative examinations adjunct with intraoperative use of appropriate pharmacologic and mechanical devices can yield favorable outcomes in cataract surgery with a small pupil.

Wavefront-guided vs wavefront-optimized LASIK: a randomized clinical trial comparing contralateral eyes.

PURPOSE: To compare wavefront-guided and wavefront-optimized LASIK in patients with myopic astigmatism up to -7.00 diopters (D) sphere and 3.00 D cylinder. METHODS: In this prospective, comparative study, 41 patients had wavefront-guided LASIK in one eye and wavefront-optimized LASIK in the fellow eye. The LASIK flap was created with a Hansatome XP microkeratome (Bausch & Lomb). The ALLEGRETTO Concerto excimer laser (WaveLight Laser Technologie AG) was used for photoablation. Pupil centroid shift and cyclotorsion were not compensated in the wavefront-guided treatments. The ALLEGRETTO Wave analyzer was used to measure ocular wavefront aberrations, and the CSV-1000 instrument (VectorVision) was used to measure contrast sensitivity before and 1 and 3 months after LASIK. RESULTS: Preoperative mean spherical equivalent refraction was -4.25±1.19 D (range: -7.50 to -2.50 D) and -4.15±1.21 D (range: -7.13 to -1.75 D) in the wavefront-guided and wavefront-optimized groups, respectively. Three months postoperatively, 33 (89.2%) eyes in the wavefront-guided group and 31 (83.8%) eyes in the wavefront-optimized group had uncorrected distance visual acuity of 20/20. Higher order aberrations increased from 0.28±0.08 µm (range: 0.13 to 0.48 µm) and 0.26±0.08 µm (range: 0.13 to 0.55 µm) to 0.45±0.17 µm (range: 0.18 to 0.71 µm) and 0.45±0.16 µm (range: 0.21 to 0.84 µm) in the wavefront-guided and wavefront-optimized groups, respectively. Except for C6 trefoil (P=.006), all Zernike polynomials increased in both groups postoperatively with no statistical difference between groups in spherical aberration (P=.41), C7 coma (P=.67), C8 coma (P=.79), and trefoil (P=.82). Contrast sensitivity did not decrease in either group and no statistically significant differences between groups were noted. CONCLUSIONS: Higher order aberrations, especially spherical aberration, increasd approximately the same amount in both groups.