Mean Keratometric Astigmatism Research Articles

Rigid Corneal Lenses for Visual Rehabilitation in Infants With Unilateral Aphakia After Cataract Surgery: A Longitudinal Case Series.

This study investigated the safety of rigid corneal lenses in children with unilateral aphakia after cataract surgery and observed the visual rehabilitation longitudinally. This retrospective cohort study performed a 3-year follow-up of 21 infants (age 5.9±3.3 months) with unilateral congenital cataracts who started wearing rigid corneal contact lenses after cataract surgery. The basic presurgical patient information included chief complaint, intraocular pressure (IOP), axial length, corneal width, anterior segment, and fundus examination. The postsurgical visual acuity, IOP, and anterior segment were examined during regular postoperative follow-up visits. Keratometry was performed when contact lenses had to be changed. Of the 21 patients, 15 were male and 6 were female. Before surgery, the affected and nonaffected eyes had similar IOP (9.5±3.5 vs. 9.2±2.8 mm Hg; P=0.502) and axial length (19.2±1.5 vs. 19.4±0.96; P=0.333). The corneal diameter in the affected eyes was smaller than in the nonaffected eyes (10.2±0.7 vs. 10.6±0.6 mm; P=0.002). After surgery, the logarithm of the minimum angle of resolution vision of the affected eyes improved gradually, showing values of 1.12±0.28, 0.78±0.37, and 0.62±0.38 at 1, 2, and 3 years after surgery, respectively. The respective values in the unaffected eyes were 0.58±0.14, 0.40±0.13, and 0.33±0.16. The mean keratometric astigmatism and keratometry 1 and 3 years after surgery were statistically similar (2.09±1.21 vs. 1.73±1.16 D, P=0.272; 44.82±3.15 vs. 44.39±2.75 D, P=0.324, respectively). No serious complications occurred during the follow-up. The rigid corneal lens is well tolerated and safe in aphakic eyes and can effectively improve children's visual acuity after unilateral cataract surgery. For patients able to receive rigid corneal lenses, intraocular lens implantation can be delayed until after the age of three.

Comparison of Toric Intraocular Lens Axis Accuracy between Optical Biometry and Dual Scheimpflug Topography.

To evaluate the accuracy of toric intraocular lens (IOL) axis prediction between two preoperative measurement devices: the optical biometry (IOLMaster 500 or 700) and the dual Scheimpflug topography (Galilei G4). Medical records of 64 eyes from 44 patients who underwent phacoemulsification and posterior chamber toric IOL (Zeiss AT TORBI 709M) implantation between July 2017 and January 2022 were reviewed. All patients underwent preoperative evaluation by optical biometry (IOLMaster 500 or IOLMaster 700) and Galilei G4. The gold-standard axis that minimizes astigmatism was calculated by the online Toric Results Analyzer postoperatively and compared to the preoperative toric IOL axis calculated by the Z CALC online IOL calculator using parameters from either IOLMaster or Galilei G4. The axis error (AE) and the absolute axis error (AAE) between the gold-standard axis and the preoperative calculated axis were analyzed to assess the accuracy of each device. Mean flat keratometry (K) and steep K were 42.99 diopter (D) and 45.61 D in IOLMaster, and 43.04 D and 45.51 D in Galilei G4, which did not show any significant difference. Mean keratometric astigmatism (KA) was 2.62 D in IOLMaster and 2.46 D in Galilei G4, which also did not show any statistical difference. KA axis did not show any significant difference between IOLMaster and Galilei G4. The mean AE and AAE were 0.19° and 6.84° by IOLMaster, and -0.80° and 7.98° by Galilei G4. The AE and AAE by IOLMaster did not show any significant difference compared to those of Galilei G4 (p=0.583, p=0.346, respectively). This study suggests that the Galilei G4 demonstrated a similar level of accuracy to the IOLMaster in predicting the toric IOL axis, based on the gold standard axis provided by the toric results analyzer.

Short-term variability in ocular biometry and the impact of preoperative dry eye.

This study aimed to investigate the short-term variability of ocular biometric measurements and to analyze the factors associated with high variability of biometric values in patients with cataract. This retrospective study included 60 eyes of 60 patients who underwent ocular biometry twice with the IOLMaster 700 (March to November 2023). Ocular surface parameters included tear film break-up time (TBUT), corneal and conjunctival staining scores (CSS/ConSS). Refractive surprise was defined as a mean absolute error exceeding 0.5 diopter (D). Participants included 22 men and 38 women with a mean age of 70.6 ± 8.4 years. The variability of mean keratometric (K) values and astigmatism showed notable variability compared to axial length (mean K: 0.18 ± 0.17D, astigmatism: 0.21 ± 0.26D, axial length: 0.01 ± 0.01mm). A decreased TBUT and increased CSS were significantly associated with high variability (≥ 0.25D) of mean K (p = 0.040/0.008). The high K variability group (≥ 0.25D) revealed a significantly higher incidence of refractive surprise (> 0.5D) compared with the low K variability group (< 0.25D) (45.5%/17.9%, p = 0.037). Preoperative lower TBUT and higher CSS influenced the variability of K values in ocular biometry and may be related with postoperative refractive surprise due to erroneous K values.

Distribution and Characteristics of Ocular Biometric Parameters among a Chinese Population: A Hospital-Based Study.

This study aimed to describe the distribution and characteristics of ocular biometric parameters among a large Chinese population. This retrospective cross-sectional study included 146,748 subjects whose ocular biometric parameters were measured at the ophthalmology clinic of West China Hospital, Sichuan University, and recorded in the hospital database. Ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, were recorded. Only monocular data for each subject were analyzed to avoid bias. Valid data from 85,770 subjects (43,552 females and 42,218 males) aged 3-114years were included in this study. The mean axial length, mean anterior chamber depth, average corneal keratometry, and mean keratometric astigmatism were 24.61mm, 3.30mm, 43.76D, and 1.19D, respectively. The stratification of the ocular parameters by age and gender showed significant inter-gender and inter-age differences. Analysis of a large population of subjects in western China aged 3-114years showed that the distribution and characteristics of ocular biometric parameters, including axial length, anterior chamber depth, corneal keratometry, and keratometric astigmatism, differed by age and gender. This study is the first to describe ocular biometric parameters in subjects aged > 100years.

One-Year Outcomes of Intracorneal Ring-Segment Insertion Assisted by Femtosecond Laser Simultaneously Performed with Corneal Collagen Cross-Linking for Treatment of Keratoconus.

PurposeTo assess the results of simultaneously performed femtosecond laser–assisted Keraring intrastromal corneal ring–segment insertion and corneal collagen cross-linking for the treatment of keratoconus.Patients and MethodsIn this retrospective, noncomparative, interventional study, 30 eyes of 24 progressive-keratoconus patients of both sexes aged 18–36 years old with poor best-corrected visual acuity (BCVA) and intolerance to contact lenses were included. All patients had been subjected to complete preoperative and postoperative ophthalmological examinations — unaided VA, BCVA, refraction, Pentacam, and contrast sensitivity examinations at 3-month, 6-month, and 1-year follow-ups.ResultsMean unaided VA had changed significantly from 0.649±0.239 logMAR preoperatively to 0.514±0.222 (P=0.014), 0.419±0.162 (P<0.001), and 0.379±0.142 (P<0.001) logMAR at the three follow-up visits, respectively. Mean BCVA had changed significantly from 0.326±0.144 logMAR preoperatively to 0.231±0.140 (P=0.006) at 1-year follow-up. Mean spherical equivalent refraction had decreased significantly at 6-month (P=0.0298) and 1-year follow-up (P=0.0081). Mean steep keratometry (K2) had also significantly reduced from 51.89±3.81 D to 49.87±4.57 D (P=0.034) at 6 months and 49.40±4.39 D (P=0.011) at 1 year. Mean refractive and keratometric astigmatism had significantly decreased at all follow-up visits.ConclusionAt 1-year follow-up, keraring intrastromal corneal ring–segment insertion assisted by femtosecond laser performed simultaneously with corneal collagen cross-linking resulted in an improvement in visual, refractive, and topographic outcomes, which may suggest it is an effective treatment of keratoconus.

Paired Opposite 4 mm Clear Corneal Incisions on Steep Meridian during Phacoemulsification.

Purpose:To evaluate the effect of opposite clear corneal incisions (OCCI) with 4 mm incisions on the steep meridian on postoperative astigmatism.Methods:This study was performed on 64 eyes of 55 patients with keratometric astigmatism of ≥ 1 diopter (D) undergoing phacoemulsification. Patients were divided into two groups, with-the-rule (WTR) astigmatism and against-the-rule (ATR) astigmatism. Initial incisions in the WTR group were performed on the temporal side with 3.2 mm keratome and paired stab incisions were performed on the steep meridian. At the end of the surgery, stab incisions were enlarged to 4 mm. Follow-up visits were scheduled at 1, 3, 6, and 12 months postoperatively, which included refraction and keratometry.Results:It was found that the mean preoperative keratometric astigmatism was 2.06 ± 0.86 D. The postoperative mean keratometric astigmatism was 1.3 ± 0.7 D after 1 month and 1.2 ± 0.7 D after 12 months. The mean astigmatism correction between the preoperative measure and that taken at 1 month was statistically significant (P = 0.001), but there was no significant change in the severity of astigmatism afterward. The mean surgically-induced astigmatism was found to be 1.99 ± 0.9 D. The 12-month changes of mean absolute astigmatism were: 1.06 ± 0.7 D in the WTR group, and 0.53 ± 0.7 D in the ATR group. The difference between the two groups was statistically significant (P = 0.02).Conclusion:Based on our findings, we posit that paired OCCI on the steep axis, using 4 mm incisions is an effective technique to correct preoperative astigmatism.

Aberrometric, Keratometric, and Visual Outcomes After Trans-Epithelial Topography-Guided Phototherapeutic Keratectomy for the Treatment of Irregular Corneas.

PurposeTo assess the safety, aberrometric and keratometric changes, and stability of trans-epithelial topography-guided phototherapeutic keratectomy (TE-TG-PTK) with mitomycin C (MMC) using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism.MethodsThis is a retrospective case series including 57 eyes that underwent TE-TG-PTK + MMC using the ALLEGRO Topolyzer platform for the treatment of irregular astigmatism. CDVA, manifest refraction (MR), keratometry readings, and aberrometry readings were analyzed at 1, 3, 6, and 12 months.ResultsCauses of corneal irregularity included non-infectious leucoma (n=23), infectious leucoma (n=7), adenoviral keratitis (n=20), corneal haze (n=2), post-penetrant keratoplasty (PKP) (n=1), and others (n=4). Overall, 76% of the eyes (n=40) gained lines of vision; patients gained 1, and 2 or more lines of vision in 76%, and 38% of cases, respectively. Only 1 patient (2%) lost 5 lines of vision. Mean preoperative CDVA (LogMAR) was 0.37 ±0.31 and improved to 0.14 ±0.18 (p<0.001) at final follow-up (12 months). CDVA remained unchanged in 10 eyes (21%). No significant changes were observed in mean keratometry (Kmean) and keratometric astigmatism readings. Regarding aberrometry, only changes in coma proved to be significant 6 months after surgery (P<0.01). No intraoperative/postoperative complications were reported.ConclusionAt final follow-up, significant improvements were observed in CDVA and coma. TE-TG-PTK + MMC proved to be an effective and safe procedure for the treatment of corneal irregular astigmatism due to several causes.

Morphometric evaluation and measurements of primary pterygium by anterior segment optical coherence tomography and its relation with astigmatism.

Purpose:To evaluate the relationship between measurements and various morphometric parameters of primary pterygium on anterior segment optical coherence tomography(AS-OCT) and refractive and keratometric astigmatism.Methods:In this cross-sectional study, patients with primary pterygium were included. The AS-OCT parameters of pterygium consisting of epithelial thickness near apex(µm), apical or head thickness(µm), its thickness at limbus(µm), horizontal length of pterygium(mm), central corneal thickness (µm) and maximum pterygium thickness(mm) were evaluated.Results:Sixty three patients comprising of 63 eyes with a primary pterygium were studied. The mean keratometric and refractive astigmatism were 1.69 ± 3.15 Diopter(D) and0.5 ± 1.4D, respectively. There was a significant association between pterygium grade and stocker’s line with keratometric astigmatism (p = 0.02, 0.00) respectively. Vertical and horizontal length on slit lamp and horizontal length on AS-OCT showed significant association with keratometric astigmatism (p = 0.05, 0.00,0.00), respectively. Limbal thickness on AS-OCT showed significant positive correlation with refractive astigmatism (r = 0.29, p = 0.02).Conclusion:The pterygium grade influences the keratometric astigmatism. Increased limbal thickness of pterygium on AS-OCT leads to more refractive astigmatism.

Topography-Guided Photorefractive Keratectomy for Postkeratoplasty Astigmatism: Long-Term Outcomes.

To evaluate the long-term efficacy and safety of topography-guided photorefractive keratectomy (TG-PRK) for postkeratoplasty refractive error correction. A retrospective interventional case series of 54 eyes of 50 patients who underwent previous corneal transplants. Unaided distance visual acuity (UDVA) and best corrected visual acuity (CDVA), manifest refraction, mean central keratometric value, mean keratometric astigmatism, and postoperative complications were reviewed. Final follow-up was at mean 31 (±17) months. Sixteen point seven percent of eyes underwent more than 1 surface ablation. Mean UDVA improved from 0.96 ± 0.06 logarithm of the minimum angle of resolution (LogMAR) preoperatively to 0.46 ± 0.05 LogMAR of resolution at the final follow-up (Bonferroni, P < 0.0001). Mean UDVA improved by 4.4 Snellen lines. Improvement in CDVA was not significant, although a significant improvement was noted when eyes with preoperative CDVA <20/40 were analyzed separately (t test, P = 0.005). Mean astigmatism improved from -4.4 ± 0.26 D preoperatively to -2.4 ± 0.26 D at the final follow-up (Bonferroni, P < 0.0001), whereas mean SEQ improved from -2.5 ± 0.39 D preoperatively to -1.1 ± 0.25 D (Bonferroni, P = 0.02). In total, 9% at the preoperative visit and 55% at the final visit had less than 2 D of astigmatism, respectively. Keratometric astigmatism decreased from 5.24 ± 0.36 D preoperatively to 2.98 ± 0.34 D at the final follow-up (t test, P < 0.0001). No eyes developed clinically significant haze, 14.8% developed regression, and 13% had a reduction of 2 or more CDVA lines. Postkeratoplasty topography-guided photorefractive keratectomy has good long-term efficacy and safety, resulting in significant UDVA, refractive, and keratometric improvement. Regression can occur after the first year of treatment, emphasizing the importance of long-term follow-up.

Peripheral Pneumatic Dissection and Scar Peeling to Complete Deep Anterior Lamellar Keratoplasty in Eyes With Healed Hydrops.

To describe a surgical technique to achieve the desired plane during deep anterior lamellar keratoplasty (DALK) in eyes with Descemet membrane (DM) tears due to previous hydrops. This was a prospective, consecutive, interventional case series of DALK in 12 keratoconic eyes with healed hydrops. Dissection of the peripheral cornea was performed by air injection and using the microbubble incision technique as a guide to the clear predescemetic stroma. The central posterior scar was then removed by peeling to bare DM. DALK was successfully completed in all eyes, with DM tears ranging from a microperforation to approximately 4 mm. At 12 months, the mean logMAR best-corrected visual acuity was 0.38 ± 0.07, the mean keratometric astigmatism was 5.2 ± 1.9 diopters, and the mean endothelial cell density was 2364 ± 316.9 cells/mm. Peripheral pneumatic dissection and central scar peeling technique is a useful technique to complete DALK in eyes with scars due to previous hydrops.

Effects of astigmatic keratotomy combined with scleral tunnel incisions for the treatment of high astigmatism after penetrating keratoplasty.

The present study aimed to evaluate the efficacy, predictability and safety of astigmatic keratotomy (AK) combined with scleral tunnel incisions in the treatment of high astigmatism after penetrating keratoplasty (PKP). Paired AK combined with scleral tunnel incisions was performed at the steep astigmatic meridian in 8 eyes of 8 patients with high keratometric astigmatism [>5.0 diopters (D)] after PKP. Pre- and post-operative parameters, including uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction and keratometric astigmatism were evaluated. The Alpins method for vector analysis was used to evaluate the changes in keratometric astigmatism. The results indicated a statistically significant reduction in the mean keratometric astigmatism from 8.16±3.02 D pre-operatively to 2.28±1.07 D at 3 months postoperatively. The mean UCVA improved from 0.95±0.24 logarithm of the minimum angle of resolution (logMAR) pre-operatively to 0.61±0.17 logMAR at 3 months postoperatively (P<0.05). The mean BCVA improved from 0.41±0.18 logMAR pre-operatively to 0.26±0.12 logMAR at 3 months postoperatively (P>0.05). Between 3 and 6 months after the surgery, the keratometric astigmatism remained stable. Alpins vector analysis demonstrated the relative predictability of this combined surgical treatment. The surgically induced astigmatism was significantly correlated with the target induced astigmatism (r=0.76, P<0.05). None of the patients had any severe complications. The present study indicated that AK combined with scleral tunnel incisions is an effective, relatively predictable and safe treatment for high astigmatism after PKP.

Office-based Relaxing Incision Procedure for Correction of Astigmatism after Deep Anterior Lamellar Keratoplasty.

Purpose:To report the outcomes of a simple and effective office-based procedure for the correction of astigmatism after deep anterior lamellar keratoplasty (DALK).Methods:This study enrolled 24 consecutive keratoconic eyes that developed an intolerable amount of graft astigmatism after DALK. The location and extension of steep semi-meridians were determined using corneal topography. Office-based relaxing incision procedures were performed at the slit-lamp biomicroscope using a 27-gauge needle. Relaxing incisions were made at the donor-recipient interface on one side of the steepest meridian with an arc length of 45° to 60° and an initial depth of approximately 70–80% of the corneal thickness. Topography was performed after 30–40 minutes and the initial incision was enhanced in depth and length. If an acceptable amount of astigmatism was not achieved, another incision was created at the opposite semi-meridian during the same session.Results:Mean follow-up period was 13.1 ± 7.4 months. Mean preoperative best spectacle corrected visual acuity was 0.26 ± 0.14 logMAR, increasing to 0.22 ± 0.09 logMAR after the procedure (P = 0.20). Mean spherical equivalent refractive error increased from − 4.64 ± 3.06 diopters (D) preoperatively to −6.06 ± 3.15 D postoperatively (P = 0.01). Mean keratometric astigmatism was reduced by 2.95 ± 3.43 D and 5.16 ± 2.97 D measured using subtraction and vector analysis methods, respectively (P < 0.001). Microperforation occurred in one eye, which spontaneously improved with no sequelae.Conclusion:Office-based relaxing incision is a safe and effective procedure for the treatment of corneal graft astigmatism after DALK. This approach effectively decreases the need for the more costly alternative in the operating room.

Influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery.

BackgroundTo examine the influence of posterior corneal astigmatism on postoperative refractive astigmatism in pseudophakic eyes after cataract surgery.MethodsThe study enrolled 64 pseudophakic eyes of 50 patients (71.8 ± 9.9 years old, mean ± standard deviation) who had undergone phacoemulsification with non-toric IOL implantation. Refractive astigmatism was measured using an auto ref-keratometer with a 0.01- diopter (D) scale. Two types of corneal astigmatism were calculated using anterior segment optical coherence tomography; keratometric and total corneal astigmatism. Keratometric astigmatism was obtained based on anterior corneal curvature alone and total corneal astigmatism was calculated using both anterior and posterior corneal curvatures. The difference between refractive and corneal astigmatism was computed as the vector difference using 1) refractive and keratometric astigmatism and 2) refractive and total corneal astigmatism.ResultsThe mean refractive, keratometric, and total corneal astigmatism was 0.92 ± 0.48 D, 0.87 ± 0.44 D, and 0.94 ± 0.46 D, respectively. The difference between refractive and keratometric astigmatism (0.70 ± 0.40 D, mean vector of 0.30 D axis 164°) was significantly larger than the difference between refractive and total corneal astigmatism (0.63 ± 0.38 D, mean vector of 0.12 D axis 137°) (P = .019).ConclusionsThe difference between refractive and total corneal astigmatism, calculated using both anterior and posterior corneal curvatures, was significantly smaller than the difference between refractive and keratometric astigmatism using anterior corneal astigmatism alone, implying that the latter overestimates the true postoperative refractive astigmatism and can cause cylindrical inaccuracy after cataract surgery.

Femtosecond laser penetrating corneal relaxing incisions combined with cataract surgery

To evaluate the effectiveness of femtosecond laser penetrating corneal relaxing incisions (CRIs) in reducing corneal astigmatism during cataract surgery. Shanxi Eye Hospital, Taiyuan, Shanxi Province, China. Prospective case series. Using the Lensx laser, CRIs were placed at a diameter of 8.0mm with a depth of 90%. Corneal astigmatism was measured before surgery and 1 and 3months after surgery. Vector analyses were performed. To obtain the net corneal changes, the with-the-wound (WTR) and against-the-wound (ATR) changes were calculated along the meridian of the CRI. Multiple regression analysis with generalized estimating equations was used to evaluate the factors contributing to the effectiveness of CRIs. The study comprised 51 eyes. One and 3months postoperatively, respectively, the mean keratometric astigmatism was reduced significantly by 0.65 diopter (D) and 0.67 D (both P<.05); compared with preoperative corneal astigmatism, the percentage of eyes within ±0.50 D of refractive astigmatism significantly increased by 42.6% and 46.7% (both P<.05) and the mean refractive astigmatism was significantly decreased at 1month (0.27 @ 93 versus 0.17×17) (P<.05) but not at 3months (0.09 @ 138 versus 0.07×172) (P>.05). The mean WTW and ATW changes were -1.05 D and -1.00 D, respectively, and 14.9% and 6.7% of eyes, respectively, were overcorrected. Age, CRI length, and CRI location were factors contributing to net corneal changes. A nomogram is proposed. Femtosecond laser CRIs were effective in reducing corneal astigmatism during cataract surgery, and their long-term effectiveness should be evaluated. Dr. Koch is a consultant to Abbott Medical Optics, Inc., Alcon Laboratories, Inc., and Revision Optics, Inc. None of the other authors has a financial or proprietary interest in any material or method mentioned.

Development of a nomogram for femtosecond laser astigmatic keratotomy for astigmatism after keratoplasty

To develop a nomogram for femtosecond laser astigmatic keratotomy (AK) to treat post-keratoplasty astigmatism. Three academic medical centers. Retrospective interventional case series. A review of post-keratoplasty femtosecond laser AK was performed. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, and keratometry were recorded preoperatively and 1, 3, 6, and 12 months postoperatively. The location, length, depth, and diameter of the AK incisions were recorded, and the surgically induced astigmatic correction was related to these variables using regression analysis. One hundred forty femtosecond laser AK procedures were performed after penetrating keratoplasty (PKP) (n = 129) or deep anterior lamellar keratoplasty (DALK) (n =11), with 89 procedures (80 PKP, 9 DALK) included in the analysis. The mean CDVA improved from 20/59 (0.47logMAR ± 0.38 [SD]) preoperatively to 20/45 (0.35 ± 0.31 logMAR) postoperatively (P= .013) (n = 46). The mean keratometric astigmatism decreased from 8.26 ± 2.90 diopters (D) preoperatively to 3.62 ± 2.59 D postoperatively (P < .0001) (n = 89). The mean refractive cylinder decreased from 6.77 ± 2.80 D preoperatively to 2.85 ± 2.57 D postoperatively (P < .0001) (n= 69). A nomogram for femtosecond laser AK to treat post-keratoplasty astigmatism was generated using regression analysis. Femtosecond laser AK significantly improved UDVA and CDVA and significantly reduced keratometric astigmatism and refractive cylinder after keratoplasty. The nomogram generated should improve the accuracy of post-keratoplasty femtosecond laser AK. None of the authors has a financial or proprietary interest in any material or method mentioned.

Factors Predicting Refractive Outcomes After Deep Anterior Lamellar Keratoplasty in Keratoconus

To determine the factors that predict refraction, mean keratometry, and keratometric astigmatism after deep anterior lamellar keratoplasty (DALK) in keratoconus. Consecutive interventional case series. This study enrolled 194 consecutive eyes of 181 patients with keratoconus who underwent DALK using the big-bubble technique. Indications for surgery included contact lens intolerance or poor corrected visual acuity. Univariate analyses and analysis of covariance were used to investigate recipient-, surgical-, and postoperative-related variables capable of predicting refractive outcomes, including mean keratometry, keratometric astigmatism, and spherical equivalent refraction. The mean patient age was 27.9 ± 8.2 years, and the patients were followed for 35.9 ± 18.2 months postoperatively. Preoperative mean keratometry (P = .007), time interval from surgery to running suture removal (P = .01), and suture-tract vascularization (P = .04) significantly influenced postoperative mean keratometry. Vitreous length predicted postoperative spherical equivalent (P = .03). Postoperative keratometric astigmatism failed to demonstrate any significant correlation with the preoperative, surgical, and postoperative variables. Postoperative refractive outcomes did not change relative to patient age and sex, central and peripheral corneal thickness, recipient trephination size, surgical technique (big-bubble vs manual dissection DALK), duration of steroid administration, and elevated intraocular pressure. Keratoconus patients with an elongated posterior segment and/or steep corneas should be informed of the need for postoperative optical correction after DALK. Running suture removal should be postponed for as long as possible if there is no suture-related complication.

Evaluation of a toric intraocular lens with open-C-loop haptic

To assess the rotational stability of a single-piece intraocular lens (IOL) with C-loop haptic during the first six postoperative months. Department of Ophthalmology, Hietzing Hospital, Vienna, Austria. Prospective clinical trial. This study enrolled consecutive patients with 1.5 diopters (D) or more of preexisting corneal astigmatism having cataract surgery. Patients had phacoemulsification with implantation of the open-C-loop toric IOL Lentis Unico LU-312 T through a 2.5 mm astigmatically neutral incision. Uncorrected distance visual acuity (UDVA) and best corrected visual acuity (BCVA), refraction, keratometry, and the cylinder axis of the toric IOL were measured. Postoperative examinations were scheduled at week 1, month 1, month 3, and month 6. A total of 60 eyes of 39 patients were evaluated. The mean preoperative refractive astigmatism was 2.82± 1.34 D (SD) and the mean keratometric astigmatism 2.33 ± 1.10 D, respectively. Six months postoperatively the refractive cylinder decreased significantly to 1.12 ± 0.63 D. The mean postoperative UDVA was 79.05 ± 7.48 letters, improving to 83.78 ± 5.60 letters BCVA. The mean IOL rotation was 5.22 ± 5.82° (range: 0.0–32) at month 6 with less than 10° in 88.3 % of eyes. Five eyes needed reoperation due to IOL misalignment. The Lentis LU-312 T showed some tendency to rotate for up to 6 months. The C-loop design seems to be less suitable for toric IOLs.

Intrastromal corneal ring segment implantation for ectasia after refractive surgery.

To evaluate the clinical outcomes of intrastromal corneal ring segment (ICRS) implantation to correct ectasia in eyes with prior refractive surgery. Forty-one eyes of 25 patients (13 men, 12 women; mean age, 28.66 years) with ectasia after refractive surgery [photorefractive keratectomy (PRK) or laser in situ keratomileusis (LASIK)] were included in a nonrandomized, retrospective, observational case series. Corneal tunnels were created by mechanical dissection in all eyes. Main outcome measures included uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BCVA), refraction, keratometry, and computerized analysis of corneal topography. Patients were divided into two groups by the type of refractive surgery (Group A: PRK, Group B: LASIK). The mean preoperative manifest astigmatism decreased from -1.88 to -0.84 D in Group A (p=0.096) and -3.18 to -1.77 D in Group B (p=0.000). The mean keratometric astigmatism decreased from -2.58 to -1.66 D in Group A (p=0.010) and -4.80 to -2.78 D in Group B (p=0.000). The mean spherical equivalent decreased from -2.97 to -2.05 D in Group A (p=0.065) and -3.31 to -2.42 D in Group B (p=0.014). No significant between-group differences were noted on the comparison of preoperative and postoperative results. No intraoperative or postoperative complications were observed. ICRS implantation is a useful treatment option for ectasia following refractive surgery, and it has significantly reduced the refractive cylinder and increased best spectacle-corrected visual acuity.

Deep anterior lamellar keratoplasty for keratectasia after laser in situ keratomileusis

To assess the efficacy of deep anterior lamellar keratoplasty (DALK) for treating post-LASIK keratectasia. Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. Retrospective interventional cases series. The same surgeon performed all DALK procedures using the Melles manual technique. The preoperative and postoperative corrected distance visual acuity (CDVA), spherical equivalent (SE) refraction, keratometry (K) readings, and endothelial cell profiles were compared. The cohort comprised 20 eyes of 18 patients (72% women) with a mean age of 29 years ± 4 (SD). The mean follow-up was 31.8 ± 17.0 months (range 6 to 60 months). The mean Snellen CDVA improved significantly from 20/191 before DALK to 20/23 after DALK (P < .001). The mean of the modulus of SE refraction was 11.9 ± 6.6 diopters (D) and 11.4 ± 4.3 D, respectively (P = .446). The mean K value was 52.2 ± 7.0 D before DALK and 46.0 ± 1.9 D after DALK (P = .001); the mean apical K value, 59.5 ± 5.1 D and 49.9 ± 2.8 D, respectively (P < .001); and the mean keratometric astigmatism, 4.3 ± 2.4 D and 1.9 ± 1.2 D, respectively (P = .003). The endothelial cell profile did not change significantly, and no major complications related to DALK occurred. Twelve eyes had additional refractive procedures to correct residual ametropia. Deep anterior lamellar keratoplasty using the Melles manual technique was effective and safe in restoring CDVA in patients with post-LASIK keratectasia; however, high residual ametropia was a common finding.

Surgical outcomes of isolated lens coloboma with or without cataract among young adults

ObjectiveTo evaluate the visual and refractive outcomes after phacoemulsification surgery in eyes with isolated lens coloboma. DesignProspective, consecutive case series. ParticipantsEighteen eyes with isolated lens coloboma of 13 patients were included in the study. Mean patient age was 13.9 ± 6.5 years. MethodsPatients underwent phacoemulsification surgery, with combined implantation of capsular tension ring (CTR) and intraocular lens. In colobomas of less than 120°, a CTR was used, whereas in colobomas of more than 120°, a Cionni-modified single eyelet CTR was used to achieve better capsular centration. The main outcome measures were uncorrected distance visual acuity, corrected distance visual acuity, refraction, and keratometry. ResultsMean logMAR uncorrected distance visual acuity and corrected distance visual acuity improved significantly from 1.53 ± 0.35 and 1.02 ± 0.47 before surgery to 0.67 ± 0.51 and 0.52 ± 0.49 at the last visit of the follow-up (p < 0.001). Mean refractive cylinder and spherical equivalent decreased significantly from –6.73 ± 1.73 and –6.72 ± 4.07 D preoperatively to –1.40 ± 1.39 and –0.83 ± 1.31 D at the end of the follow-up (p = 0.001 and p = 0.01, respectively). Mean keratometric astigmatism at preoperative and postoperative visits were 1.58 ± 0.97 and 1.65 ± 0.94 D, respectively (p = 0.70). ConclusionsPhacoemulsification with CTR and intraocular lens implantation is an effective and safe option for providing a refractive correction and a significant visual improvement in eyes with isolated lens coloboma.