Evaluation of Ocular Residual Astigmatism in Eyes with Myopia and Myopic Astigmatism and Its Interaction with Other Forms of Astigmatism.

Purpose: To evaluate the prevalence, magnitude, and direction of ocular residual astigmatism (ORA) in eyes with myopia and myopic astigmatism, and its interaction with refractive, anterior corneal, posterior corneal, and true net power astigmatism. Patients and Methods: Refractive surgery candidates with myopia and myopic astigmatism were studied. Refractive astigmatism (RA) was measured using the Nidek® AR-310A autorefractometer. Anterior corneal astigmatism (ACA), posterior corneal astigmatism (PCA), and true net power astigmatism (TNP) were measured using the Wavelight® Oculyzer II. Astigmatism was converted from polar to vector notation. ORA was calculated by vector subtraction of ACA from RA vertexed to corneal plane. Compensation factor (CF) was calculated as the ratio of ORA that compensates ACA for both J0 and J45. Results: 154 eyes of 88 patients (mean age 31.7±7.1 years) were included. With-the-rule (WTR) astigmatism was the most common for both RA (55.6%) and ACA (74%), while against-the-rule (ATR) was the most common for PCA (87.7%) and ORA (74.0%). The axes of RA and ACA were within 10° of each other in 46.8% of the eyes, and within 30° of each other in 76.0%. The mean difference in value between the axis of RA and ACA was 25.6°. 71.4% of eyes in the study had an ORA ≥ 0.5D, 44.1% had ORA ≥ 0.75D and 26% had ORA ≥ 1D. There was a statistically significant difference between ACA and each of RA and TNP. Using TNP to calculate ORA instead of ACA reduced its magnitude. RA is positively correlated to ACA and more strongly to TNP. The most common pattern of compensation between ORA and ACA was under-compensation for J0 (49%) and same-axis-augmentation for J45 (35%). Conclusion: ORA, PCA, and the interaction between ORA and ACA can affect results during refractive planning.

Comparison of Refractive Outcomes in Small-Incision Lenticule Extraction Performed with One or Two Incisions.

PURPOSE: To retrospectively compare the refractive outcomes between two groups of small-incision lenticule extraction (SMILE), one with a single incision and the second one with dual-incisions. SETTING: Ebsar Eye Center, Benha, Qalyopia, Egypt. DESIGN: A retrospective cohort study. METHODS: This study was made up of two groups (162 eyes each): all eyes in group 1 had one SMILE cut at 120°, and all eyes in group 2 had double SMILE incisions, the first incision at 120° and the second one at 270°. Refractive outcomes between the two groups were compared at 3, 6, and 12 months after surgery. RESULTS: The mean preoperative refractive spherical equivalent (MRSE) was -5.75 ± 2.59 D and -6.38 ± 2.18 D in group 1 and 2, respectively (P = 0.73), and a cylinder of 1.25 ± 0.83 D and 0.75 ± 0.81 D, respectively (P = 0.85). At 12 months postoperatively, in group 1, 162 eyes (100%) achieved a UCVA of 20/25, 154 eyes (95.06%) achieved a UCVA of 20/20, and 110 eyes (67.90%) achieved 20/16. In group 2, 162 eyes (100%) achieved a UCVA of 20/25, 156 eyes (96.29%) achieved a UCVA of 20/20, and 113 eyes (69.75%) achieved 20/16. The mean MRSE at 12 months postoperatively was -0.25 ± 0.33 D in group 1 and -0.5 ± 0.33 D in group 2 (P = 0.62). CONCLUSION: Dual-incision SMILE is safe and effective as single-incision SMILE, with a predictable and stable effect in correcting myopia and myopic astigmatism.

Topography-Guided Femto-LASIK in Virgin Eyes: Treating Manifest versus Measured Astigmatism.

PURPOSE: To assess the stability, safety, predictability, and efficacy of topography-guided myopic Femto-LASIK with two different treatment protocols. SETTING: Ebsar Eye center, Benha, Qalyopia, Egypt. DESIGN: Single-center, retrospective, COHORT control study. METHODS: A total of 330 eyes enrolled in the study in group A and 322 eyes enrolled in group B underwent uncomplicated primary bilateral topography-guided Femto-LASIK. Group A was treated with the subjective clinical refraction; however, group B was treated with the modified refraction according to ALCON protocol. RESULTS: The mean preoperative refractive spherical equivalent (MRSE) was -4.85±1.90D and -5.0±1.93D in group A and B, respectively (P = 0.86), and a cylinder of -0.95±0.80 D and -0.92±0.81D, respectively. At the 12 months' postoperatively, the residual manifest SE within ± 0.5D was achieved by 82.86% of eyes in group A compared to 83.93% in group B. Of eyes, 92.06% had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group A (315 eyes); however, 91.80% of eyes had ≤0.5 astigmatism dioptre, while 100% of eyes had ≤1.0 astigmatism dioptre in group B. CONCLUSION: Topographic modification of the magnitude and axis of astigmatism treated using ALCON protocol when different from the clinical refraction may offer good refractive outcomes when we apply the Alcon precalculation considerations.

Outcomes of Small Incision Lenticule Extraction with Dual-Incisions in Myopic Patients.

PURPOSE: To assess the stability, safety, predictability, and efficacy of small incision lenticule extraction (SMILE) with dual-incisions in myopic patients. SETTING: Ebsar Eye center, Benha, Qalyopia, Egypt. DESIGN: Single-center, retrospective, COHORT study. PATIENTS AND METHODS: The study was conducted as a retrospective non-comparative analysis of the records of 105 eyes of 53 patients treated by the SMILE with a dual-incisions technique for a mean spherical myopic error of -5.05 ± 1.93 D (range: -1.38 to -9.0 D) with or without astigmatism and the mean astigmatism of -0.90 ± 0.83 D. The mean LogMAR corrected distance visual acuity (CDVA) was -0.04 ± 0.07. RESULTS: One month after surgery, the mean refractive error was -0.03 ± 0.56 D (range: 0.88 to -1.50 D), and the mean postoperative astigmatism was 0.20 ± 0.31 D. The mean LogMAR UDVA was 0.07 ± 0.18 in the last follow-up visit, 12 months after surgery. At the end of the follow-up period, approximately 91.43% of patients had unchanged CDVA or gained one or more lines, 8.57% lost one line of CDVA, and 0.0% lost 2 lines. CONCLUSION: SMILE with dual-incisions is effective and safe, with a stable and predictable outcome for correction of myopia and myopic astigmatism.

SMILE intraoperative complications: incidence and management.

AIM: To report the intraoperative complications associated with small incision lenticule extraction (SMILE) and their management. METHODS: This was a retrospective consecutive interventional clinical study, carried out on patients with myopia and myopic astigmatism, who underwent SMILE procedure. Type of intraoperative complications and their management were recorded. RESULTS: Our study comprised 282 eyes of 141 patients who were enrolled for SMILE surgeries. The intraoperative complications included lost vacuum (18 eyes, 6.38%), treatment decentration (6 eyes, 2.12%), wound bleeding (21 eyes, 7.45%), incomplete bubble separation (black islands) (3 eyes, 1.06%), the epithelial defects (15 eyes, 5.32%). Incision tear (27 eyes, 9.57%), lenticule adherence to the cap (6 eyes, 2.12%), and cap perforation occurred in 2 eyes (0.7%). CONCLUSION: Although SMILE is a promising technique for the correction of myopia and myopic astigmatism with predictable, efficient, safe refractive and visual outcomes, complications can occur. However, most of them are related to inexperience and are included in the learning curve of the technique. More studies with a bigger number of eyes are required to efficiently evaluate the intraoperative complications and standardize their management strategies.

Intraoperative complications of refractive small incision lenticule extraction in the early learning curve.

PURPOSE: To study the intraoperative complications of refractive small incision lenticule extraction (ReSMILE push-up technique), and to record the mean intraoperative duration time of all surgeries for the refractive surgeon in his early learning curve. SETTING: Ebsar Eye Center, Benha, Egypt. DESIGN: A prospective, single-center, cohort clinical study. METHODS: This prospective, single-center, cohort clinical study was done on patients with myopia and myopic astigmatism, who were enrolled for SMILE surgeries. All the SMILE operations were performed by a single refractive surgeon (AMH), by using only the ReSMILE push-up technique. RESULTS: A total of 190 eyes were operated upon, using the (ReSMILE push-up technique), with a mean follow-up period of 2 months. The intraoperative complications have been recorded for all patients. The mean operative duration of all cases was 4.45±1.45 minutes. CONCLUSION: The ReSMILE: push-up technique seems to facilitate visualization of the edge of the lenticule of the SMILE surgery, especially for the refractive surgeon in his early learning curve.

Efficacy of transepithelial corneal collagen crosslinking for keratoconus: 12-month follow-up.

PURPOSE: To evaluate the efficacy of transepithelial corneal collagen crosslinking (TE-CXL) in patients with progressive keratoconus. PATIENTS AND METHODS: This is a prospective interventional consecutive study carried out on 30 eyes of 18 patients with progressive keratoconus who underwent TE-CLX using both ParaCel™ (riboflavin 0.25%, hydroxy propyl methyl cellulose, NaCl, ethylenediaminetetraacetic acid [EDTA], Tris, and benzalkonium chloride) and vibeX-Xtra (riboflavin 0.22%, phosphate-buffered saline solution). The procedure was carried out at Ebsar Eye Center in Egypt in the period from 2012 to 2014. The follow-up visits were scheduled on days 1, 3, 6, and 12 months after treatment. RESULTS: There were statistically significant improvements (P<0.001) in the mean best-corrected visual acuity (0.54±0.22 preoperatively vs 0.61±0.19 at 12 months postoperatively), the mean manifest refraction spherical equivalent (MRSE; -6.16±3.90 diopters [D] preoperatively and -5.91±3.72 D at 12 months postoperatively), and the mean preoperative corneal astigmatism (-3.39±2.11 D preoperatively and -2.46±2.60 D at 12 months postoperatively). CONCLUSION: TE-CXL could halt the progression of keratoconus in adult patients. TE-CXL resulted in a statistically significant improvement in best-corrected visual acuity, manifest refraction, refractive and corneal astigmatism and K values in keratoconus patients at the 12-month follow-up. Larger sample sizes and longer follow-ups are required in order to make meaningful conclusions.

Refractive and visual outcomes after Keraring intrastromal corneal ring segment implantation for keratoconus assisted by femtosecond laser at 6 months follow-up.

PURPOSE: We attempted to evaluate the efficacy of femtosecond laser-assisted intrastromal corneal ring segment implantation in patients with keratoconus (KC). PATIENTS AND METHODS: A retrospective interventional consecutive clinical study was conducted on patients with KC who were treated with femtosecond laser Keraring implantation. All procedures were performed at Ebsar Eye Center in the period from January 5, 2015, to February 28, 2016. RESULTS: Thirty eyes of 20 patients were included in this study. The mean age of patients was 27.43±3.57 years. Eleven patients (55%) were female and nine patients (45%) were male. Keraring segments were successfully implanted in all eyes. There were no complications or need for ring repositioning. The follow-up period was 6 months postoperatively. There was a significant improvement in the mean logarithm of the minimum angle of resolution (LogMAR) of uncorrected visual acuity (UCVA) after Keraring segment implantation from 1.5±0.23 preoperatively to 0.54±0.16 at 6 months postoperatively (P=0.001). The preoperative mean LogMAR of best-corrected visual acuity (BCVA) was 0.85±0.17. At 1 month postoperatively, it was 0.35±0.15; at 3 months postoperatively, it was 0.26±0.11, and at 6 months postoperatively, it was 0.14±0.07 (P=0.001). The mean preoperative maximum keratometric value for 3 mm pupil in diopters (K max) significantly decreased from 55.85±5.44 preoperatively (N=30) to 44.05±1.64 D at 6 months postoperatively (P=0.001). There was a statistically significant reduction in the mean preoperative spherical equivalent from -5.43±1.76 D preoperatively to -2.43±0.95 D at 6 months postoperatively. No statistically significant differences were detected between 1 and 3 months of follow-up regarding the visual and refractive outcomes. CONCLUSION: Analysis of the outcomes after Keraring ICRS implantation showed a significant postoperative corneal flattening with a subsequent increase in UCVA and BCVA. Using the femtosecond laser for tunnel creation made the procedure easy and fast with an accurate precise depth of implantation and reduced the risk of operative and postoperative complications.

Refractive small-incision lenticule extraction: Push-up and push-down techniques.

We describe 2 techniques for manipulating the edge of the lenticule in refractive small-incision lenticule extraction. In the push-up technique, an instrument with a Y-shaped tip is inserted through the incision and used to push the edge of the lenticule up, facilitating visualization of the edge of the lenticule, which might accelerate the learning curve of the beginning surgeon. The push-down technique is used if the surgeon notices that the lenticule is adherent to the cap after 1 surface has been dissected, making dissection of the superficial surface difficult. The same Y-shaped instrument can be used to engage the edge of the lenticule and push it down to make room to introduce the dissector; this is followed by dissection of the lenticule from the cap using the dissector. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned.

Initial experience with an accommodating intraocular lens: controlled prospective study.

PURPOSE: To evaluate the outcomes of implantation of an accommodating intraocular lens (IOL) in pseudophakic presbyopic eyes. SETTING: Ophthalmology Department, Benha Medical School, Benha, Egypt. METHODS: In this prospective controlled trial, near and distance visual acuities, the manifest refraction spherical equivalent, and patient satisfaction were evaluated in presbyopic eyes that had phacoemulsification cataract removal and implantation of a Crystalens AT-45 IOL accommodating IOL. The difference between preoperative and postoperative mean values was compared using the Student t and paired-sample t tests. Comparison between postoperative follow-up visits was by analysis of variance. RESULTS: The study comprised 25 eyes (23 patients; 13 men). The mean IOL power was 21.80 diopters (D) +/- 1.45 (SD) (range 19.00 to 24.00 D). At 6 months, 23 eyes (92%) had an uncorrected distance visual acuity (UDVA) of 6/12 or better; all eyes had a corrected distance visual acuity (CDVA) of 6/12 or better (P = .000). The difference in CDVA and UDVA between 1 month and 6 months postoperatively was not statistically significant. The mean distance-corrected near visual acuity (DCNVA) was J5 at 1 month and 6 months; from 1 month on, the DCNVA was J3 or better in more than 60% of eyes. There was a statistically significant difference in DCNVA between preoperatively and 6 months postoperatively (P = .021). CONCLUSIONS: Initial experience indicates that the accommodating IOL provides functional near and distance visual acuity for daily tasks. Surgeon experience and refinement of IOL calculations are required to improve outcomes. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

A comparative analysis of five methods of determining corneal refractive power in eyes that have undergone myopic laser in situ keratomileusis.

OBJECTIVE: To evaluate the accuracy of computerized videokeratography, keratometry, and the Gaussian optics formula for measuring corneal refractive power in patients after myopic laser in situ keratomileusis (LASIK). DESIGN: Noncomparative case series. PARTICIPANTS: One hundred eyes of 63 patients (mean age, 45.0 +/- 10.9 [standard deviation] years) who underwent LASIK were included in the study. METHODS: Using the clinical history method as the standard, we evaluated the accuracy of values of corneal refractive power derived from computerized videokeratography (the EffRP value of the EyeSys Corneal Analysis System, which averages corneal refractive power over the central 3 mm), keratometry (K), the Gaussian optics formula (GauRP), and values of EffRP and keratometry as modified according to the amount of LASIK-induced refractive change. MAIN OUTCOME MEASURES: Correlation of measured corneal power values to those obtained using clinical history method (HisRP). RESULTS: Although the values for HisRP were significantly correlated with postoperative EffRP and K values and with GauRP, postoperative EffRP and K values were higher than HisRP (0.87 +/- 0.68 diopters [D] and 1.16 +/- 1.10 D, respectively), and GauRP were lower than HisRP (0.44 +/- 0.66 D) (P < 0.001 for all three comparisons). The differences between HisRP and both postoperative EffRP and K values increased significantly with the amount of myopic correction. The most accurate results were obtained by modifying the postoperative values of EffRP according to the amount of LASIK-induced refractive change; 70% of these values were within +/- 0.5 D and 94% within +/- 1 D of HisRP values. CONCLUSIONS: Using the clinical history method as the standard, we found that the most accurate method for determining corneal refractive power in post-LASIK eyes was to adjust the postoperative corneal measurement according to the amount of LASIK-induced refractive change.