Subjective Astigmatism Research Articles

Vector analysis of moderate to high myopic astigmatism after small-incision lenticule extraction (SMILE): 12-month follow-up.

To evaluate the refractive outcomes of small-incision lenticule extraction (SMILE) surgery in moderate to high myopic astigmatism. Prospective interventional case series. This study evaluated 111 eyes of 68 patients treated with femtosecond SMILE surgery for the correction of myopia and astigmatism. Inclusion criteria were myopia of - 0.5 D or more and astigmatism between - 1.0 D and -5.0 D. Refractive and visual measurements were obtained preoperatively, 1 and 12 month(s) postoperatively. Vector analysis was used to study the astigmatic outcomes at 12-month follow-up. Comparison of results in two groups of patients with astigmatism below and over 3.00 D was performed. The preoperative mean spherical equivalent was -5.48 ± 2.17 D (range - 1.75 to - 10.00 D) and the mean cylinder was -2.02 ± 1.09 D (range - 1.00 to - 5.00 D). The mean postoperative cylinder value was -0.60 ± 0.52 D at 12-month visit. The 12-month safety and efficacy indices were 0.98 ± 0.07 and 0.97 ± 0.12, respectively. The high astigmatism group showed significantly lower safety and efficacy indices. The postoperative residual astigmatism was 0.5 D or less in 73% of the eyes. Higher amount of residual astigmatism was observed in the high astigmatism group. The angle of error was ± 5 degrees in 49% and ± 15 degrees in 87% of the eyes. SMILE surgery is effective and safe method for correcting myopic astigmatism. Vector analysis indicated a tendency for the under correction of astigmatism in subjects with high astigmatism.

Toric intraocular lens power calculation in cataract patients with keratoconus.

Intraocular lens (IOL) power calculation in eyes with keratoconus typically results in hyperopic postoperative refractive error. The purpose of this study was to investigate the visual and refractive outcomes in patients with keratoconus having cataract surgery with a toric IOL and compare IOL power calculation accuracy of conventional formulas and keratoconus-specific formulas. Ein-Tal Eye Center, Tel-Aviv, Israel. Retrospective case-series study. Postoperative visual acuity and manifest refraction were examined. The error in predicted refraction and IOL power calculation accuracy within a range of 0.50 to 2.00 diopters (D) were compared between different IOL calculating formulas. 32 eyes with keratoconus were included. Visual acuity improved in all cases, and subjective astigmatism decreased from -2.95 ± 2.10 D to -0.95 ± 0.80 D (P < .001). The mean absolute errors were as follows: Barrett True-K formula for keratoconus with measured or predicted posterior corneal power, 0.34 D; Barrett Universal II formula, 0.64 D; Kane formula, 0.69 D; Kane formula for keratoconus, 0.49 D; SRK/T formula, 0.56 D; Haigis formula, 0.72 D; Holladay 1 formula, 0.71 D, and Hoffer Q formula, 0.87 D. Barrett True-K formula with measured posterior corneal power, SRK/T formula, and Kane formula for keratoconus resulted in a prediction error within ±0.50 D of 87.5%, 59.4%, and 53.1%, respectively. Cataract removal with a toric IOL significantly improves visual acuity and decreases astigmatism in keratoconic eyes with a topographic central relatively regular astigmatic component. Keratoconus-specific formulas resulted in lower mean error in predicted refraction compared with conventional calculating formulas. Using the posterior corneal power within the Barrett True-K formula for keratoconus improved IOL power prediction accuracy.

Short-Term Efficacy and Safety of Cataract Surgery Combined with Iris-Fixated Phakic Intraocular Lens Explantation: A Multicentre Study.

The purpose of this study was to evaluate the short-term efficacy and safety of cataract surgery for patients with iris-fixated phakic intraocular lenses (pIOLs). This study included 96 eyes of 91 patients. The changes in the logMAR uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), subjective spherical equivalent (SE), astigmatism, and endothelial cell density (ECD) were collected retrospectively. The intraoperative and postoperative complications also were investigated to assess the surgical safety. The preoperative UCVA and BCVA improved significantly at month 1 postoperatively, respectively (p < 0.001 for both comparisons). The efficacy and safety index at month 1 postoperatively were 1.02 ± 0.56 and 1.31 ± 0.64, respectively. The SE at month 1 postoperatively was significantly (p < 0.001) higher compared to preoperatively, whereas the subjective astigmatism did not differ significantly (p = 0.078). The ECD significantly decreased at month 1 (p < 0.001). The most common postoperative complication was intraocular pressure elevation exceeding 25 mmHg in 10.4% of eyes, which was controlled with medications in all cases until month 1 postoperatively. No intraoperative complications developed. Cataract surgeries for patients with iris-fixated pIOLs were performed safely with good visual outcomes.

Prediction of distance visual acuity in presbyopic astigmatic subjects

This study was aimed to determine the effect of the amount of astigmatism on distance visual acuity, and to provide a prediction formula of visual acuity according to astigmatism, in a presbyopic population. We comprised 318 eyes of 318 consecutive patients (158 phakic and 160 pseudophakic subjects) without any eye diseases, except for refractive errors with astigmatism of 3 diopter or less. We assessed the relationship of the spherical equivalent visual acuity (SEVA) with astigmatism, and also provided a regression formula of visual acuity according to astigmatism in such subjects. We found a significant correlation between the SEVA and the amount of astigmatism (r = 0.715, p < 0.001) in the entire study population. We obtained similar results, not only in phakic eyes (r = 0.718, p < 0.001), but also in pseudophakic eyes (r = 0.717, p < 0.001). The regression formula was expressed as follows: y = 0.017x2 + 0.125x − 0.116 (R2 = 0.544), where y = logMAR SEVA, and x = astigmatism. We also found no significant differences in the SEVA for matched comparison among the with-the-rule (WTR), against-the-rule (ATR), and oblique (OBL) astigmatism subgroups (p = 0.922). These regression formulas may be clinically beneficial not only for estimating the visual prognosis after astigmatic correction, but also for determining the surgical indication of astigmatic correction.

Astigmatism prediction in small-incision lenticule extraction.

To investigate whether postoperative-induced refractive astigmatism after small-incision lenticule extraction (SMILE) could be predicted by preoperative objective astigmatism measured with autorefraction, keratometry, and Scheimpflug tomography. University eye clinic. Retrospective case series. Only eyes without preoperative subjective astigmatism treated with SMILE for myopia were included. Postoperative subjective astigmatism was compared with preoperative objective astigmatism. Examinations were performed before SMILE and 3 months postoperatively and included subjective refraction, keratometry, autorefraction, and Scheimpflug tomographer measurements. Astigmatism was analyzed using double-angle plots and multivariate statistics. A total of 358 eyes of 358 patients were included. The mean preoperative sphere was -7.33 diopter (D) ± 1.46 (SD). The postoperative spherical equivalent was -0.30 ± 0.49 D. Postoperatively, 79.6% and 98.9% of patients had a subjective cylinder ≤0.50 D and ≤1.00 D, respectively. Preoperative objective astigmatism measured with keratometry, autorefraction, and Scheimpflug tomography was significantly different (P < .05) from postoperative subjective refraction when all patients were analyzed; for patients with postoperative refractive astigmatism ≥0.50 D, preoperative astigmatism with keratometry and Scheimpflug tomography was not significantly different from postoperative refractive astigmatism. Preoperative objective astigmatism ≥0.50 D increased the risk ratio of postoperative subjective astigmatism ≥0.50 D by 2.2 (P < .001). Preoperative objective astigmatism could not be directly interchanged with postoperative subjective astigmatism, but the presence of preoperative astigmatism ≥0.50 D doubled the risk of inducing a postoperative subjective astigmatism ≥0.50 D. Extra care when performing subjective refraction should be taken in the presence of high objective astigmatism.

Four-year outcomes of small incision lenticule extraction (SMILE) to correct high myopic astigmatism

AimsTo evaluate the long-term outcomes of small incision lenticule extraction (SMILE) in subjects with myopic astigmatism of ≥2.00 dioptres (D).MethodsPatients who underwent SMILE 4 years prior with astigmatism ≥2.00 D...

Kinetic visual acuity, stereopsis, and ocular deviation with an implantable collamer lens

To compare kinetic visual acuity, stereopsis, ocular deviation, and fusion amplitude before and after implantable collamer lens (ICL) surgery. Sanno Hospital. Retrospective analysis. The charts of adult patients who underwent implantation of an ICL with a central aquaport (V4c) for emmetropia were reviewed. The mean preoperative spherical equivalent and subjective astigmatism were -7.87 diopters (D)±3.13 (SD) and -0.75±0.78 D, respectively. All measurements were obtained with full refraction before surgery and without spectacle correction after surgery. The kinetic visual acuity was measured with the AS-4D device. Stereopsis and ocular deviation were measured with the Titmus Stereotest and an alternate prism cover test, respectively. Fusion amplitude was determined from breakpoints measured using a prism. The study comprised 29 adult patients (58 eyes). One month postoperatively, the mean safety and efficacy indices were 1.13 ± 0.20 and 0.96 ± 0.25, respectively, and 57 eyes (98.7%) were within ±0.5 D of the target correction. The mean kinetic visual acuity (logarithm of the minimum angle of resolution) was 0.30 ± 0.21 preoperatively and 0.20 ± 0.15 (Snellen 20/40 versus 20/32) postoperatively and the mean stereopsis (seconds of arc), 48.5 ± 1.6 versus 41.5 ± 1.1; both improved significantly (P < .001 and P = .012, respectively). The mean distance ocular deviation (-4.0 ± 3.8 prism diopters [Δ] versus 2.8 ± 3.6 Δ; P = .002) and near ocular deviation (-6.5 ± 6.7 Δ versus 5.4 ± 6.9 Δ; P = .04) decreased significantly. The fusion amplitude increased for near vision only. ICL implantation improved kinetic visual acuity and stereopsis, decreased ocular deviation, and increased near fusion amplitude.

December consultation #5

To compare kinetic visual acuity, stereopsis, ocular deviation, and fusion amplitude before and after implantable collamer lens (ICL) surgery.Sanno Hospital.Retrospective analysis.The charts of adult patients who underwent implantation of an ICL with a central aquaport (V4c) for emmetropia were reviewed. The mean preoperative spherical equivalent and subjective astigmatism were −7.87 diopters (D) ± 3.13 (SD) and −0.75 ± 0.78 D, respectively. All measurements were obtained with full refraction before surgery and without spectacle correction after surgery. The kinetic visual acuity was measured with the AS-4D device. Stereopsis and ocular deviation were measured with the Titmus Stereotest and an alternate prism cover test, respectively. Fusion amplitude was determined from breakpoints measured using a prism.The study comprised 29 adult patients (58 eyes). One month postoperatively, the mean safety and efficacy indices were 1.13 ± 0.20 and 0.96 ± 0.25, respectively, and 57 eyes (98.7%) were within ±0.5 D of the target correction. The mean kinetic visual acuity (logarithm of the minimum angle of resolution) was 0.30 ± 0.21 preoperatively and 0.20 ± 0.15 (Snellen 20/40 versus 20/32) postoperatively and the mean stereopsis (seconds of arc), 48.5 ± 1.6 versus 41.5 ± 1.1; both improved significantly (P < .001 and P = .012, respectively). The mean distance ocular deviation (−4.0 ± 3.8 prism diopters [Δ] versus 2.8 ± 3.6 Δ; P = .002) and near ocular deviation (−6.5 ± 6.7 Δ versus 5.4 ± 6.9 Δ; P = .04) decreased significantly. The fusion amplitude increased for near vision only.ICL implantation improved kinetic visual acuity and stereopsis, decreased ocular deviation, and increased near fusion amplitude.

Epithelial Photorefractive Keratectomy and Corneal Cross-linking for Keratoconus: The Tel-Aviv Protocol.

To present the Tel-Aviv Protocol for patients with progressive keratoconus, which consists of epithelial photorefractive keratectomy (ePRK), and corneal cross-linking (CXL). This was a retrospective case series of 20 consecutive patients diagnosed as having progressive keratoconus at Care-Vision Laser Centers, Tel Aviv, Israel. The Tel-Aviv Protocol included laser epithelial ablation using the EX500 excimer laser (Alcon Laboratories, Inc., Fort Worth, TX) with 50% of the manifest refractive astigmatism (on the same axis) while the spherical ablation is added so as not to exceed a total of 50-µm ablation of the epithelium and anterior stroma. Afterward, all patients underwent CXL. Data collected included thinnest corneal thickness (TCT), subjective astigmatism, mean keratometric power, maximum keratometric power (Kmax), uncorrected distance visual acuity (UDVA), and corrected distance visual acuity (CDVA). A total of 20 eyes of 20 patients with a mean age of 28.0 ± 6.5 years (range: 13 to 40 years) and a mean follow-up of 823 ± 337 days (range: 266 to 1,749 days) were included. There was a significant improvement in both UDVA (from 0.95 ± 0.73 to 0.22 ± 0.15 logMAR, P < .001) and CDVA (from 0.24 ± 0.13 to 0.13 ± 0.12 logMAR, P < .001) at the end of the follow-up period. There was a significant improvement in mean keratometry (from 46.86 ± 2.48 to 45.00 ± 2.27 diopters [D], P < .001), Kmax (from 48.18 ± 2.74 to 45.97 ± 2.55 D, P < .001), and Kmin (from 45.54 ± 2.35 to 44.03 ± 2.12 D, P < .001). TCT was significantly lower following the procedure (from 450.90 ± 35.99 to 404.90 ± 43.96 µm, P < .001). No complications and no progression in keratoconus severity were noticed during the follow-up period. The Tel-Aviv Protocol for patients with progressive keratoconus provides good improvement in visual acuity and astigmatism while halting the progression of keratoconus. [J Refract Surg. 2019;35(6):377-382.].

A Simple, Inexpensive, and Precise Photographic Method for Intraoperative Toric IOL Alignment.

It was the aim of this study to analyse the refractive outcome of toric intraocular lens (t-IOL) implantation guided by a newly developed method of photographic alignment. Fourteen eyes of 10 patients (6 females, 4 males, age 63.4 ± 6.7 (40.6 - 68.0) years [mean ± 1 SD (range)]) were included in this retrospective study. All eyes received an Oculentis Tplus LS-313 (Oculentis, Berlin, Germany) t-IOL after standard phacoemusification (n = 4) or femtocataract laser-assisted surgery (n = 10). Image-guided t-IOL alignment included: (1) calculation of t-IOL parameters (combination of different biometric methods) and plotting a layout drawing of the target lens position, (2) capture of an anterior segment slit lamp photograph in the upright position, (3) superposition of the photographs by the t-IOL target plot and a gradual scale, (4) drawing of marker lines on the photograph and removal of the IOL target coordinates, (5) transfer of the final image to a tablet PC, and (6) marking of the target axis at the corneal limbus with an ink pen in the surgical room. Preoperative corneal astigmatism was 2.50 ± 0.97 (1.38 - 4.34) diopters (D) (mean ± 1 SD, range). In all eyes, intraoperative alignment could easily be performed using the photographic target layout. Surgical interventions and postoperative follow-up were without complications in all cases. Residual postoperative astigmatism was 0.16 ± 0.24 (0.00 - 0.75) D (p < 0.001 compared to preoperative astigmatism). In 64% of patients, residual subjective astigmatism was zero, in 93% ≤ 0.5 D, and in 100% ≤ 0.75 D. Postoperative uncorrected logMAR visual acuity (0.05 ± 0.07, range 0.00 - 0.20) and best-corrected visual acuity (0.03 ± 0.05, 0.00 - 0.10) were significantly better (each p < 0.001) than best-corrected preoperative visual acuity (0.21 ± 0.14, 0.00 - 0.49). Results of this clinical series clearly indicate that the newly developed photographically guided technique of toric lens alignment leads to highly accurate postoperative results for astigmatic correction.

Type of astigmatism in subjects with nystagmus of age 5-15 years

Type of astigmatism in subjects with nystagmus of age 5-15 years

Comparison of two techniques for toric intraocular lens implantation: hydroimplantation versus ophthalmic viscosurgical devices

BackgroundTo compare the results between hydroimplantation of a single-piece, acrylic foldable toric intraocular lens (IOLs) and conventional implantation using an ophthalmic viscosurgical device (OVD).MethodsIn this study, 60 eyes with cataract and preexisting regular corneal astigmatism of 1.0 to 3.0 diopters (D) underwent the implantation of the AcrySof toric IOLs (Alcon Laboratories, Inc.). The patients were randomly assigned to a conventional implantation technique with an OVD or a hydroimplantation technique. Comparison of preoperative and postoperative parameters was performed using paired Student t tests, and independent Student t test was used to compare between the two groups.ResultsThree months postoperatively, the mean subjective astigmatism was 0.45 D ± 0.24 (SD) in the OVD group and 0.49 ± 0.29 D in the hydroimplantation group (P = 0.492). The mean endothelial cell density (ECD) loss was 7.54% ± 0.82% and 7.32% ± 0.59%, respectively (P = 0.117). The mean absolute IOL rotation was 4.77 ± 2.32 degrees and 4.70 ± 1.95 degrees, respectively (P = 0.334). The mean time for IOL implantation was 71.50 ± 8.10 s and 37.60 ± 3.90 s, respectively (P < 0.001). Two hours, 1 day, 1 week, 1 month, and 3 months postoperatively, there was no significant difference in IOP between the two groups (P > 0.05), although IOP two hours postoperatively seemed to be a little higher in the OVD group.ConclusionsCompared with the use of OVDs for toric IOLs implantation, the hydroimplantation technique provided advantages of increased efficiency, reduced surgical time and cost, and no concerns of OVD-induced elevated IOP.Trial registrationCurrent Controlled Trials ISRCTN55696872, Retrospectively registered (Date of registration: 25 March 2018).

Prevalence of refractive errors among school children in the rural field practice area of a tertiary care hospital, Bengaluru

Background: An estimated 19 million children are visually impaired, and 12 million are visually impaired due to refractive errors. Children fall in preventable age group for correction of refractive errors. Schools are best forum for implanting health education for children and for early detection of ocular morbidity. This study was undertaken to assess the prevalence of refractive errors among school children in rural field practice area of Rajarajeswari Medical College and Hospital, Bengaluru.Methods: A cross sectional study was conducted among the schools in rural field practice area of Rajarajeswari Medical College and Hospital School children aged between 7-16 years were examined for defective vision using Snellens chart. General information of the children was collected using pre-designed and semi- structured questionnaire a. Children with abnormal vision were referred to hospital. Data was analyzed using SPSS software. Descriptive statistics was used and chi-square test of significance was applied.Results: 1140 study subjects were examined out of which 577 (50.6%) were females and 563 (49.4%) males. The mean age was 11.28 years. The prevalence of refractive errors was 10.5%.The prevalence of refractive errors was significantly associated with age (p&lt;0.05). The prevalence of myopia, hypermetropia and astigmatism in study subjects was 58.5%, 17.1%, 24.4% respectively.Conclusions: The prevalence of refractive errors, especially myopia, was higher in older children. Causes of higher prevalence and barriers to refractive error correction services and compliance should be identified and addressed. Eye screening of school children is recommended.

Implantation torique : comparaison du marquage horizontal manuel versus automatique, à propos de 50 cas

The main objective of our study is to evaluate the contribution of automated conjunctival recognition in the alignment of toric implants by comparing the automatic alignment optimized with Callisto™ to the manual marking of the horizontal axis. We performed a prospective, descriptive, and monocentric study on patients undergoing cataract surgery with toric implantation (Asphina 709Zeiss), operated by a surgeon with good experience in toricity, between September 2016and March 2017. We analyzed the agreement between the manual marking of the 0°-180° axis versus the one automatically generated by the Callisto™, as well as the alignment of the IOL and the refractive results at 1month. We included 50eyes of 26patients. The corrected mean astigmatism was 1.9D. The mean difference between the 2axes was 4.7° [0°-12.3°]. Only 50% of the preoperative manual markings were consistent with the automatic measurement (<5°). At one month, the average rotation recorded was 4.3° [0°-29°]. The alignment was identical for 70% (n=35) of the IOL (≤5°). As for residual subjective astigmatism, it was on average 0.58D. The mean visual acuity without correction was 8/10and 55% had 10/10without correction. The refractive performance depends on the preoperative measurement, the correct alignment of the IOL and its stability in the bag. Our study shows the value of automatic conjunctival recognition in the determination of the axis of peroperative alignment, even in an experienced operator. This precision is essential for a good refractive result, especially since the residual astigmatism in case of misalignment will increase with the power of the implant. Our study shows excellent refractive results, whatever the initial astigmatism, using the automatic alignment. The precision of the toric implantation opens the way to the toric multifocal implantation under the best conditions.

Toric lens implantation in cataract surgery: Automated versus manual horizontal axis marking, analysis of 50 cases

The main objective of our study was to evaluate the contribution of automated conjunctival registration in the alignment of toric intraocular lenses by comparing automated registration optimized with Callisto® to manual marking of the horizontal axis. We performed a prospective, descriptive, monocentric study on patients undergoing cataract surgery with a toric intraocular lens (Asphina 709Zeiss), performed by a surgeon with good experience in toric implants, between September 2016and March 2017. We analyzed the agreement between the manual marking of the 0-180° axis versus the one automatically generated by the Callisto™, as well as the alignment of the IOL and the refractive results at 1month. We included 50eyes of 38patients. The mean corrected astigmatism was 1,9D.The mean difference between the 2axes was 4,7° [0-12.3°]. Only 50% of the preoperative manual markings were consistent with the automated measurement (<5°). At one month, the mean rotation recorded was 4,3° [0-29°]. The alignment was identical for 70% (n=35) of the IOLs (≤5°). As for residual subjective astigmatism, the mean was 0.58D.The mean visual acuity without correction was 8/10and 55% saw 10/10without correction. Refractive performance depends on preoperative measurement, correct alignment of the IOL and its stability in the bag. Our study shows the value of automated conjunctival registration in the determination of the intraoperative axis of alignment, even with an experienced surgeon. This precision is essential for a good refractive result, especially since residual astigmatism in the case of misalignment will increase with the power of the implant. Our study shows excellent refractive results, regardless of the initial astigmatism, using automated alignment. Precision of toric implantation opens the way to toric multifocal implantation under the best conditions.

Visual and Topographical Outcomes Following Accelerated Trans-Epithelial Corneal Crosslinking in Progressive Keratoconus.

To assess the visual and topographical outcomes following accelerated trans-epithelial corneal crosslinking (TE-CXL) in progressive keratoconus. Case series. Laser Vision Centre, Karachi, from January 2015 to December 2016. Forty-five eyes of 25 patients affected with progressive keratoconus and treated with accelerated TE-CXL with riboflavin (vitamin B2) and ultra-violet A(UV-A) irradiation were enrolled in this study. The visual outcome was measured by ETDRS chart as improvement in best corrected visual acuity (BCVA) of at least one line or more as compared to pre-CXLBCVA. The topographical outcome was measured as decrease in maximum simulated keratometry values, astigmatism and spherical equivalent (SE) and an increase in central corneal thickness (CCT). K-max was defined as the steepest radius of curvature of the anterior corneal surface. SE was measured by subjective refraction, and K-max, astigmatism and CCTby scanning-slit corneal topography. Patients were followed-up 12 months post-treatment. At the end of follow-ups, mean BCVAshowed improvement of one line from LogMAR 0.58 ±0.067 to LogMAR 0.48 ±0.077. Seven (15.5%) eyes showed two lines of improvement while 3 (6.7%) eyes showed worsening of one line in BCVA. The mean K-max flattened by 0.7D. Mean astigmatism and SE decreased up to -0.5D and -0.4D, respectively. Mean preoperative CCTwas 454.31 ±36.34 µm, whereas mean postoperative CCTwas 456.47 ±35.60 µm with an average increase of 2.15 µm. No postoperative complications were reported. Based on topographical outcomes, accelerated TE-CXL is effective in preventing the progression of keratoconus without any safety concerns with improvement of vision in majority of cases.

The impact of surgical excision on pterygium induced astigmatism

Objective: To Study the correlation between length and width of pterygium on induced astigmatism. To determine the relation between preoperative and postoperative astigmatism measured by keratometery and refraction. Results: Total 60 patients were included with male predominance (75%) and majority of patients falling in middle age group (60%). There was a strong association of pterygium with outdoor workers as compared to indoor workers. The length of pterygium had strong correlation with corneal astigmatism as compared to width. Following excision of pterygium with Conjunctival autograft with suture, there is statically significant reduction in mean corneal and subjective astigmatism. (p value

Femtosecond laser arcuate keratotomy for the correction of postkeratoplasty high astigmatism in keratoconus.

Background:Astigmatism is the leading complication in visual recovery after penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK); in this study, we evaluated the outcome of femtosecond laser arcuate keratotomy (FLAK) after DALK and PKP in Iranian keratoconic patients.Materials and Methods:In this prospective interventional case series, refractive and keratometric predictability, efficacy, and complications of FLAK for postkeratoplasty astigmatism in keratoconus were evaluated; 23 eyes of 23 consecutive patients (mean age of 32.43 ± 9.11 years) with high astigmatism were enrolled. The femtosecond laser performed paired 90°-angled arcuate incisions.Results:Mean logarithm of the minimum angle of resolution of corrected and uncorrected visual acuity improved from preoperative values of 0.30 ± 0.18 and 0.85 ± 0.32 to 6-month values of 0.19 ± 0.17 and 0.65 ± 0.33, respectively (P < 0.05). Mean subjective astigmatism was 7.79 ± 2.64 diopter (D) preoperatively and 3.69 ± 2.25D at 6-month after surgery (P < 0.05). Surgically induced astigmatism was 9.27 ± 5.00D. Mean refractive spherical equivalent showed no significant (P = 0.69) hyperopic shift from − 4.21 ± 4.84D preoperatively to − 2.16 ± 6.09D postoperatively. Two (8.7%) microperforations were observed.Conclusion:FLAK is a relatively safe and effective method for the treatment of postkeratoplasty astigmatism.

Venting incisions in DSAEK: implications for astigmatism, aberrations, visual acuity, and graft detachment

To evaluate the impact of venting incisions on the best corrected visual acuity (BCVA), astigmatism, aberrations, and risk of graft detachment in Descemet stripping automated keratoplasty (DSAEK). This was a retrospective, comparative, consecutive case series of DSAEK procedures performed with (n = 266) and without (n = 110) venting incisions. Patients were treated with DSAEK for Fuchs' endothelial dystrophy at Aarhus University Hospital between 2011 and 2013. Data included preoperative keratometry and postoperative BCVA, subjective astigmatism, and Pentacam® HR tomography with corneal front surface (CFS) aberrations at 1 to 2 years of follow-up. Numbers of triple procedures (concurrent cataract surgery) and post-operative graft detachments were also noted. The venting and non-venting groups were compared by the data-means. Unpaired t-tests and Mann-Whitney tests were used for normally and non-normally distributed data, respectively. Differences in graft detachments were analyzed with Fisher's exact and Chi square test. There was no significant difference in any parameter, except the numbers of triple procedures. BCVA (logMAR) was 0.25 ± 0.18 in the venting group and 0.25 ± 0.19 in the non-venting group (p = 0.92), subjective astigmatism was -1.53 ± 0.99 diopters and -1.33 ± 0.78 diopters (p = 0.15), respectively. CFS astigmatism and higher order aberrations were statistically uniform. The relative risk (RR) of graft detachment was also uniform between the venting versus non-venting group (RR 0.72, p = 0.40), and between triple versus non-triple procedures (RR 0.71, p = 0.43). The preoperative corneal curvature had no impact on the risk of graft detachment (p = 0.74). Venting incisions in DSAEK do not significantly alter BCVA, astigmatism, CFS aberrations or reduce the risk of graft detachment in triple or non-triple procedures.

Epithelial Ingrowth: Visual Acuity and Astigmatism Results One Year after YAG Laser Treatment

Purpose: To assess the response of YAG laser for epithelial ingrowth in LASIK patients undergoing re-treatment with flap re-lift, after one year. Materials and Methods: Prospective case series of LASIK patients with a symptomatic decrease in VA due to epithelial ingrowth (grades II-III), after retreatment with flap relift, with YAG laser (0.6-0.8 mJ) and followed-up during one year. Variables included pre and post YAG laser uncorrected visual acuity (UCVA, decimal scale), spherical equivalent (SE), topography astigmatism (SimK, 3.00 mm, and 5.00 mm zones). Data was registered and analyzed using Microsoft® Excel® 2013 (Microsoft Corporation), reported as mean, standard deviation (SD), and compared using paired t-student (p ≤ 0.05 for significance). Results: Nine patients were followed-up, for one year, 5 men and 4 women with mean age 46.8 ± 11-7 years. Pre/post results were: UCVA 0.75 ± 0.12/0.96 ± 0.09 (p=0.03), astigmatism 0.5 ± 0.68/0.10 ± 0.22D (p=0.03), SE 0.48 ± 0.46/0.25 ± 0.42D (p=0.24), topography astigmatism 2.0 ± 0.85/1.4 ± 0.45D (p=0.02), Km 39.3 ± 2.7/39.4 ± 2.4D (p=0.50). For pseudophakic patients pre/post mean UCVA 0.75 ± 0.24/0.83 ± 0.17 (p=0.22), SE 0.03 ± 0.80D / 0.06 ± 0.13D (p=0.94), astigmatism 0.49D ± 0.59/0.13D ± 0.25D (p=0.94), topographic astigmatism 2.8 ± 1.7D/2.5D ±1.1D (p=0.34). Conclusions: YAG laser treatment for symptomatic epithelial ingrowth, in LASIK patients after retreatment with flap relift, significantly improved UCVA and decreased subjective and topographic astigmatism. Clinical and topographical improvement in pseudophakic patients was not clinically significant.