Long-term results of accelerated corneal collagen crosslinking in paediatric patients with progressive keratoconus: 10-year follow-up.

OBJECTIVES: To evaluate the 10-year visual, refractive, and tomographic outcomes of epithelium-off accelerated corneal collagen cross-linking (ACCL) in paediatric patients with progressive keratoconus (KC) and to compare the stages in terms of re-progression. METHODS: Patients under 18 years of age with progressive KC who underwent ACCL between 2010 and 2012 and completed at least 10 years of follow-up were included in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, and corneal tomography parameters were evaluated preoperatively and at 1, 5, and 10 years postoperatively. The effect of stage and age on re-progression was analysed. RESULTS: The study included 175 eyes of 97 patients (mean age: 14.46 ± 2.17 years). Improvement in UDVA and CDVA was observed in all postoperative periods compared to the preoperative period (each p-value < 0.05). The increase in spherical equivalent (SE), flattening of keratometry values, and decrease in thinnest corneal thickness (TCT) were statistically significant in the tenth year compared to preoperatively (each p-value < 0.05). Re-progression was observed in 16 eyes (9.14%). Haze was observed in 13 eyes (7.43%), 4 of which were permanent. Deep anterior lamellar keratoplasty was performed in 3 eyes (1.7%) and a second ACCL in 3 eyes (1.7%). CONCLUSIONS: ACCL is an effective and safe long-term strategy to prevent progression of KC in paediatric patients. In the light of this study with a 10-year follow-up re-progression rate of 9.14%, long-term follow-up of patients after ACCL for possible re-progression and the need for re-CCL or keratoplasty may be recommended.

Comparison of three techniques for simultaneous intraocular lens implantation in subluxated cataract surgery: Transconjunctival intrascleral, Z-suture knotless transscleral, and Cionni capsular tension ring assisted.

PURPOSE: To evaluate and compare the clinical outcomes of three different methods of intraocular lens (IOL) implantation in the surgery of subluxated cataracts. METHODS: In this retrospective, comparative, clinical interventional study, the medical records of patients who underwent IOL implantation with sutureless 27-gauge needle-assisted transconjunctival intrascleral (Group 1), Z-suture knotless transscleral (Group 2), and Cionni capsular tension ring (Cionni-CTR) assisted (Group 3) simultaneously with subluxated cataract extraction between June 2010 and June 2022 were evaluated. Demographic characteristics, follow-up times, uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), spherical and cylindrical refractive values, and spherical equivalent (SE) values of three groups were compared. Intraoperative and postoperative complications were recorded. RESULTS: There were 20 eyes in Group 1, 35 eyes in Group 2, and 40 eyes in Group 3. In all groups, statistically significant improvement was observed in postoperative UDVA and CDVA compared to preoperative values (each p < 0.05). There was no statistical difference between the groups in postoperative UDVA and CDVA values. (p = 0.130, p = 0.167 respectively). No significant difference was observed between the groups in terms of postoperative spherical, cylindrical, and SE values (each p > 0.05). CONCLUSION: The study suggests that three different IOL implantation techniques for simultaneous IOL implantation in subluxated cataract surgery have similar effects on visual and refractive outcomes.

Seven-Year clinical outcomes after implantation of Eyecryl posterior chamber phakic intraocular lenses for high myopia.

PURPOSE: To evaluate the long-term clinical outcomes, safety and efficacy of Eyecryl posterior-chamber phakic intraocular lens implantation (pIOL) implantation in patients with high myopia. METHODS: Patients with myopia between -6.00 and -20.00 dioptres and with endothelial cell density (ECD) was ≥2300 cells/mm2 were included. Preoperative and postoperative first, fourth, and seventh years of refraction, uncorrected/corrected distance visual acuity (UDVA/CDVA), ECD, central vault were detected. RESULTS: Thirty-six eyes were analyzed. The mean UDVA and CDVA in postoperative seventh years were 0.25 ± 0.31 and 0.13 ± 0.24 logMAR, respectively. The safety and efficacy indices were 1.55 ± 0.54 and 1.24 ± 0.53, respectively. The mean cumulative ECD loss was 6.96% (p < 0.001). The central vault at the 1st and the 7th year were 0.52 ± 0.14 and 0.49 ± 0.14 mm, respectively (p = 0.25). CONCLUSIONS: These findings supported the long-term stability, efficacy, safety of the Eyecryl pIOL for high myopia. Eyecryl posterior chamber pIOL is one of the effective refractive options in correcting high myopia.

Effect of Keratoconus Stage and Classification Parameters on Deep Anterior Lamellar Keratoplasty Outcomes.

PURPOSE: The aim of this study was to investigate the effect of the keratoconus (KC) stage according to the Amsler-Krumeich classification system and the parameters used in this classification on deep anterior lamellar keratoplasty outcomes. METHODS: The preoperative KC stage was determined, and the presence of corneal scarring was noted. The preoperative and postoperative best-corrected visual acuity (BCVA), refractive error, mean central keratometry (K mean ) readings, topographic astigmatism, and minimum corneal thickness (CT) values were recorded. Intraoperative and postoperative complications were also noted. RESULTS: One hundred thirty-seven eyes (54 eyes in stage 3-83 eyes in stage 4) were included in the study. The mean follow-up period was 42.20 ± 24.36 months. There was no statistically significant difference between stage 3 and 4 KC groups for postoperative BCVA, K mean , CT, spherical equivalent, and topographic astigmatism values (each P value >0.05). The effect of preoperative BCVA, K mean , CT, and refractive error values on postoperative BCVA could not be demonstrated ( P = 0.264). In addition, no statistically significant correlation was found between postoperative and preoperative values (each P value > 0.05). Although intraoperative Descemet membrane perforation and postoperative early suture loosening were observed more frequently in stage 4 KC than in stage 3 KC, the 2 groups were statistically similar for these and other complications (each P value >0.05). CONCLUSIONS: The preoperative KC stage and the parameters used in classification are not useful in predicting postoperative deep anterior lamellar keratoplasty outcomes. The timing of the surgery should be planned with the awareness that the progression of the disease will not have a negative effect on outcomes.

Epithelial Inoculation After Small-Incision Lenticule Extraction (SMILE): A Case Report.

Epithelial ingrowth is a rare condition that is generally seen after laser in situ keratomileusis (LASIK) and has been reported in the literature in a small number of cases after small-incision lenticule extraction (SMILE) surgery. "Epithelial inoculation" should also be considered in patients presenting with decreased vision and an appearance similar to epithelial ingrowth in the early period after SMILE surgery. A 23-year-old woman presented to our clinic with a request for refractive surgery. Her manifest refractions were -7.50 -1.00 x 180° in the right eye and -7.25 -1.00 x 150° in the left eye, and best corrected distance visual acuity was 10/10 in both eyes. The SMILE procedure was performed with the Visumax femtosecond laser (Carl Zeiss Meditec AG). Slit-lamp examination at postoperative 1 week revealed a small grayish-white intrastromal opacity resembling epithelial ingrowth in the central optic axis of the right eye. Irrigation of the interface was performed with balanced salt solution using an irrigation cannula and the epithelial cluster was removed. The patient remained clinically stable 6 months after surgery and has experienced no recurrence. When epithelial inoculation is observed early after SMILE surgery, immediate irrigation of the interface appears to be an effective and safe treatment.

Changes in corneal high order aberrations and anterior chamber parameters following scleral fixated intraocular lens implantation.

BACKGROUND: To evaluate the change in corneal high order aberrations (HOAs) and anterior chamber parameters following scleral fixation in aphakic patients using the Scheimpflug camera system. METHODS: This retrospective study included patients who were aphakic after phacoemulsification surgery and underwent scleral-fixed intraocular lens (SF-IOL) implantation with Z suture technique between 2010 and 2022. Preoperative and postoperative best corrected visual acuity (BCVA), anterior segment parameters and corneal aberrations were evaluated with a combined Scheimpflug-Placido disk corneal topography device (Sirius Costruzione Strumenti Oftalmici, Florence, Italy). The following values were recorded: Simulated keratometry (SimK), flat meridian (K1), steep meridian (K2), iridocorneal angle (ICA), temporal anterior chamber angle (T-ACA), nasal anterior chamber angle (N-ACA), horizontal anterior chamber diameter (HACD), anterior chamber volume (ACV), corneal volume (CV), total Root Mean Square (RMS), high order aberrations (HOAs), spherical aberration, coma, trefoil, quadrifoil, and secondary astigmatism. RESULTS: The study included 31 eyes of 31 patients (mean age: 63.00 ± 19.41 years, 17 males/14 females). Postoperative BCVA was better than preoperative BCVA (p = 0.012). Postoperatively, there was a statistically significant increase in ACV and CV values and a statistically significant decrease in K2 (p = 0.009, p = 0.032, p = 0.015). Preoperative T-ACA and preoperative and postoperative ACV were negatively correlated with postoperative intraocular pressure (r=-0.427 p = 0.033, r=-0.406 p = 0.032 and r=-0.561 p = 0.001). There were statistically significant postoperative increases in corneal RMS, trefoil and HOAs for 3 mm pupil diameter (p = 0.0177, p = 0.001, p = 0.031) and in corneal RMS, trefoil and quadrifoil aberrations for 6 mm pupil diameter (p = 0.033, p = 0.001, p = 0.001). CONCLUSIONS: In conclusion, SF-IOL implantation with Z-suture technique used for visual rehabilitation of aphakic patients may affect visual quality by increasing corneal HOAs while improving visual acuity.

Comparison of Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty in Keratoconic Eyes With Previous Hydrops-Related Corneal Scar.

PURPOSE: This study aimed to compare the outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) procedures in keratoconic eyes with a previous hydrops-related corneal scar. METHODS: In this retrospective study, the medical records of patients who had hydrops-related corneal scarring and underwent keratoplasty surgery were reviewed. Patients treated with DALK were classified as group 1, and patients treated with PK as group 2. Preoperative and postoperative best-corrected visual acuity, central corneal thickness, keratometry (K), and refractive error values of each group were recorded and compared. RESULTS: Seventy-eight eyes (41 in group 1 and 37 in group 2) were included in this study. The mean follow-up period of the patients was 37.7 ± 30.0 months in group 1 and 51.2 ± 29.4 months in group 2 ( P = 0.06). The preoperative and postoperative best-corrected visual acuity and central corneal thickness values were statistically similar in both groups (each P value >0.05). Keratometry values (K1 and mean keratometry) were significantly steeper in group 1 ( P1 = 0.02 and P2 = 0.03, respectively). Descemet membrane perforation was experienced in 7 (4 macroperforation and 3 microperforation; 15.6%) of 45 eyes that planned to perform DALK. These 4 eyes with macroperforation underwent PK and were excluded from the study. When all postoperative complications were assessed, although the total complication rate was 21% after DALK, it was 43% after PK ( P = 0.04). CONCLUSIONS: DALK with a big-bubble technique is a feasible surgery in eyes with corneal scarring due to previous hydrops and is comparable with PK in terms of visual and refractive outcomes. This study suggests that DALK, which is safer than PK with less postoperative complication rates, should be the primary surgical option to avoid serious complications in keratoconic eyes with hydrops-related corneal scarring.

Efficacy of keratometric values obtained from Sirius topographer® in nidek axial length-scan® for intraocular lens calculation after penetrating keratoplasty.

BACKGROUND: To evaluate the accuracy of keratometric values obtained from Scheimpflug (Sirius) topography using Nidek AL-Scan optical biometry (OB) for intraocular lens (IOL) power calculating after penetrating keratoplasty (PK). METHODS: Thirty eyes of 26 patients were included in this study. The demographic information, complete ophthalmic examination, IOL calculation technique, and its effect on final refractive results were evaluated. RESULTS: The mean age of the patients was 52.76 ± 16.20 years. The mean K readings using Nidek AL-Scan OB, mean simulated K (SimK) (3mm), and mean pupillary power (MPP) (4.5mm) K readings using Sirius were 41.92 ± 5.05 D, 42.99 ± 5.78 D, and 43.30±6.23 D (p= 0.515). CONCLUSIONS: Both devices correctly calculated IOL power after PK; however, Sirius SimK (3mm) gave the lowest mean absolute error (MAE) results and can be safely used for IOL power calculation.

Changes in anterior chamber dimensions following small incision lenticule extraction (SMILE).

PURPOSE: To evaluate the changes in anterior chamber dimensions including horizontal anterior chamber diameter (HACD), anterior chamber depth (ACD), and iridocorneal angle (ICA) following small incision lenticule extraction (SMILE) using Scheimpflug-Placido disk tomographer (Sirius). METHODS: The records of the 73 eyes of 47 patients who received SMILE for myopia and myopic astigmatism were retrospectively reviewed. Preoperative and 6-month postoperative measurements of central corneal thickness (CCT), HACD, ACD, ICA, nasal anterior chamber angle (nACA), and temporal anterior chamber angle (tACA) were obtained by tomography, and compared with paired t-tests. Pearson's correlation and linear regression tests were used to evaluate the relationship between these parameters. RESULTS: The CCT, HACD, and ACD values decreased significantly at 6-month postoperatively (p < 0.05 for all). ICA, nACA, and tACA showed no statistically significant difference postoperatively (p = 0.54, p = 0.118, and p = 0.255, respectively). Pearson's correlation analysis confirms negative relationship between Δ-HACD and Δ-tACA (r = -0.475, p < 0.01), and a loose negative relationship between change in ACD and change in ICA (r = -0.282, p = 0.016). Age and Δ-tACA were found as predictive parameters for Δ-HACD and, Δ-ICA was a predictor for Δ-ACD. CONCLUSION: While HACD and ACD decreased significantly, there was no significant change in ICA, nACA and tACA. Changes in HACD and ACD should be considered in terms of subsequent surgeries after SMILE.

The effect of anterior segment parameters on surgical success of Descemet membrane endothelial keratoplasty: a prospective study.

PURPOSE: To investigate how anterior segment parameters affect the success of Descemet membrane endothelial keratoplasty (DMEK) in patients with endothelial insufficiency without stromal opacities and to identify factors predisposing them to repeat keratoplasty. METHODS: Our prospective observational study included patients who underwent primary DMEK for Fuchs' endothelial dystrophy and pseudophakic bullous keratopathy between March 2019 and March 2020. After a detailed ophthalmologic examination, corneal topographic analysis, anterior segment optical coherence tomography (AS-OCT) scans, endothelial cell density (ECD) and axial length (AL) measurements were performed. Surgical success was defined as no endothelial dysfunction during follow-up. Changes in the parameters and how preoperative parameters affect surgical success were investigated. RESULTS: In 43 eyes of 43 patients (mean age: 68.58 ± 8.51 years), mean visual acuity was 1.73 ± 0.74 LogMAR before DMEK and 0.31 ± 0.29 LogMAR in the final visit. Central corneal thickness (CCT, p = 0.026) and mean anterior chamber depth (ACD, p = 0.001) affected surgical success. Preoperative CCT values greater than 770 µm increased the risk of repeat keratoplasty by 8.75-fold, whereas preoperative ACD values less than 2.5 mm increased the risk by 2.92-fold. CONCLUSION: Preoperative higher CCT and lower ACD values were associated with surgical failure after DMEK. Early surgery may be considered for more successful results. TRIAL REGISTRATION: This prospective study has been registered on the ClinicalTrials.gov system with the registration number NCT04420429 on 06/06/2020.

Early intraocular pressure changes following different keratoplasty techniques and association with cornea parameters and anterior chamber depth.

Background: Corneal transplantation surgery is associated with an increased risk of intraocular pressure (IOP) elevation. Increased IOP may cause irreversible vision loss and graft failure.Purpose: We aimed to evaluate early IOP changes following different keratoplasty techniques and to investigate the relationship between corneal thickness (CT), keratometry values, anterior chamber depth (ACD), and IOP changes. Methods: We included patients who underwent penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK), and Descemet membrane endothelial keratoplasty (DMEK) in this observational study. ACD, CT, and keratometry measurements were repeated postoperatively at hour 24, week 1, and month 1. IOP measurements were repeated at postoperative hours 6 and 24, week 1, and month 1 by Tono-Pen XL. Results: In total, 22 patients underwent PK, 12 patients underwent DALK, and 19 patients underwent DMEK. The difference between the IOP preoperatively and postoperatively hour 6, and between the IOP preoperatively and postoperatively hour 24 was statistically significant in the three types of surgery (p < 0.05 for each). The difference between preoperative and postoperative week 1 IOP was statistically significant only in the PK group (p = 0.023). When the IOP was compared between the three types of surgeries, the IOP at postoperative week 1 in the PK group was significantly higher than the DALK and DMEK groups (p = 0.021). There was no correlation between ACD, CT, K values, and IOP in any group. Conclusion: IOP may increase in all types of keratoplasty during the first hours after surgery, but PK has a risk of high IOP longer in the early postoperative period. PK patients should be followed more carefully during postoperative week 1 to check for an increase in IOP.

Effect of capsular tension ring on refractive results in cases with pseudoexfoliation syndrome.

PURPOSE: To investigate the effect of capsular tension rings (CTRs) on postoperative refractive results in patients with pseudoexfoliation (PSX) syndrome. MATERIALS AND METHODS: Sixty-nine patients with PSX syndrome who had uncomplicated cataract surgery between March 2016 and February 2019 were reviewed retrospectively. The patients were divided into two groups. The 35 patients in Group 1 received CTRs prior to intraocular lens implantation during cataract surgery, and the 34 patients in Group 2 had cataract surgery without CTRs. Significant zonular weakness, uncontrolled glaucoma, and ocular pathologies causing low visual acuity were excluded. The preoperative and postoperative keratometry and autorefraction measurements, preoperative expected refractive values, and absolute refractive error were recorded. RESULTS: The mean ages of patients were 73.54 ± 9.78 years in Group 1 and 72.23 ± 6.72 years in Group 2 (p = 0.521). There was no statistically significant difference between Group 1 and Group 2 in terms of expected preoperative refraction values (-0.52 ± 0.12,-0.56 ± 0.08, respectively, p = 0.118). There was a statistically significant difference in postoperative spherical equivalent values between Group 1 and Group 2 (-0.05 ± 0.97 and -0.92 ± 0.57, respectively, p < 0.01). A statistically significant difference was found between the two groups in terms of absolute refractive error (0.46 ± 0.74 in Group 1 and -0.34 ± 0.59 in Group 2 p < 0.01). CONCLUSION: CTR implantation causes hyperopic shift, which should be taken into consideration when calculating the lens power of intraocular lens in patients with PSX syndrome.

Graft survival and clinical outcomes of Descemet membrane endothelial keratoplasty: long-term results.

PURPOSE: The aim is to report long-term graft survival rates and clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK). METHODS: In this study 150 eyes that underwent DMEK whether for Fuchs endothelial corneal dystrophy (FECD) or for bullous keratopathy (BK) surveilled for 7 years at 6 time points to evaluate graft survival rates and clinical outcomes of post-corneal transplantation. RESULTS: Overall, the estimated survival probability of 95% confidence interval at 7 years of post-DMEK was 0.58 (0.72-0.77), and the survival probabilities of eyes operated for FECD (0.53) were higher than eyes operated for BK (0.42) (log rank 26.87, [p = 0.197]). Post-transplant eyes with FECD achieved better visual acuity levels than eyes with BK (p = 0.006). Primary graft failure occurred in 11.3% eyes. Secondary graft failure rate was 9.3%, and allograft rejection rate was 4.7%. CONCLUSION: Although DMEK is effective and safe in long term, visual results and graft survival rates are better in cases with FECD.

The Effect of Secondary Intraocular Lens Implantation Time on Visual Prognosis in Aphakia Cases after Open Globe Injury.

PURPOSE: We investigated the effect of the time of secondary intraocular lens (IOL) implantation on final visual acuity and other causes affecting visual prognosis in cases left aphakic after open globe injury. METHODS: The study included 62 eyes of 62 patients left aphakic after the repair of open globe injury between 2012 and 2019. Demographic characteristics, trauma zone, ocular trauma score, type of injury, time of secondary IOL implantation, final best-corrected visual acuity (BCVA), and complications were recorded for each patient. RESULTS: The mean follow-up time of 62 patients was 25.05 ± 12.59 months. The preoperative BCVA was found to be 2.40 ± 0.86 logarithm of the minimum angle of resolution (logMAR), while the postoperative final BCVA was found to be 0.53 ± 0.70 logMAR (p < 0.01). The mean interval timing of secondary sulcus foldable IOL implantation was determined to be 3.79 ± 4.04 months. No correlation was observed between secondary IOL implantation time and final BCVA (r = 0.140, p = 0.319). Furthermore, when only pediatric patients were taken, an excellent positive correlation was found between the secondary IOL implantation time and final BCVA logMAR (r = 0.895, p < 0.01). Multiple linear regression on final BCVA with age, revealed a significant model explaining 48.0% of the variability with younger age and better final BCVA with as significant coefficients (p = 0.007). CONCLUSIONS: Although time interval between primary repair and secondary IOL implantation to correct aphakia does not effect final BCVA in adult patients, earlier surgery should be considered for amblyopia management in pediatric patients.

Predictive Factors for Corneal Scarring in Progressive Keratoconus Patients after Corneal Collagen Cross-linking.

Objectives: To evaluate predictive factors for corneal scar formation following corneal collagen cross-linking (CXL).Methods: The medical records of 295 progressive keratoconus patients who had undergone accelerated CXL were reviewed retrospectively in this comparative cohort study. Thirty-two eyes of 32 patients who still had a corneal scar in the first year (scar group) and 75 eyes of 75 patients without any scar (control group) were included. The patients' demographic characteristics, preoperative uncorrected distance visual acuity (UCVA) and corrected distance visual acuity (CDVA), slit-lamp biomicroscopy and corneal topographic parameters data were acquired from the patients' files. Multivariable logistic regression analysis and Receiver operating characteristic (ROC) curves were used for the purpose of evaluating predictive factors for corneal scar formation.Results: The UCVA and CDVA, which were determined to be similar between the groups during the preoperative period (P = .63, P = .71, respectively), improved postoperatively in both groups (P = .98, p = .10, respectively). The thinnest point of corneal thickness was statistically lower in the scar group (p = .03). In multivariable logistic regression analysis, preoperative keratometric astigmatism was a predictive value showing postoperative scar development (OR 11.81 95% CI 2.46-56.62, p = .002). Keratometric astigmatism had the highest sensitivity (90%), specificity (86.7%), and accuracy (95%) for scar formation at the best cut-off point of 5.61 D according to the ROC curve.Conclusions: A higher tendency for stromal haze development following CXL was determined in eyes with thinner corneas and higher keratometric astigmatism with the best cut-off value of 5.61 D.

Anterior Segment Surgery Performed During the COVID-19 Pandemic.

OBJECTIVES: This study evaluated anterior segment surgeries performed during the coronavirus 2019 (COVID-19) pandemic. Prevention of virus transmission is a critical consideration for surgeons, and includes assessment of etiology, the referral region, demographic characteristics, and the surgery to be performed. METHODS: The data of 144 patients who underwent anterior segment surgery between March 19, 2020 and June 1, 2020 were retrospectively reviewed. The patient demographic data and details of ophthalmological examination findings, the region patients were referred from, and the type of surgery performed were recorded and analyzed. RESULTS: A total of 144 patients, 49 women (34%) and 95 men (66%), were included in this study. The mean age of the patients was 31.30±25.88 years (range: 1-86 years). The presenting complaint was in the right eye in 43.7% of the cases, in the left eye in 52.8%, and in both eyes in 3.5% of the cases. While 94.4% of the applications were from Istanbul, the remaining 5.6% were from outside the province. Though 43.7% of the cases were patients seen previously at the study hospital in Istanbul, 56.3% presented for the first time. This hospital was the first referral center in only 39.6% of the cases. Evaluation of etiology indicated that corneal perforation (18.1%) was the most common, followed by keratitis (13.2%). The most common surgical intervention applied was amnion membrane transplantation (19.4%), followed by perforation repair (16.7%). CONCLUSION: Ophthalmological surgeries continue to be performed during the ongoing COVID-19 pandemic, however, special algorithms must be used to reduce the risk of COVID-19 transmission and to ensure continuity of healthcare for ophthalmology patients.

The Effect of Cone Localization on Higher Order Aberrations After Corneal Crosslinking for Keratoconus.

OBJECTIVES: This study was designed to evaluate the effects of corneal collagen cross-linking (CXL) on topographic parameters, visual acuity, and corneal high-order aberrations according to the preoperative cone location in keratoconus. METHODS: This retrospective study assessed patients with keratoconus who underwent CXL between March 2016 and February 2019. Patients with a history of corneal surgery, corneal hydrops, corneal scar tissue, delayed epithelial healing, and a corneal thickness of <400 µm were excluded. The included eyes were divided into 2 groups according to the preoperative cone location: maximum K in the central 3-mm optical zone (group 1) or the central 3-mm to 5-mm optical zone (group 2). The preoperative and postoperative 24-month, best-corrected visual acuity (BCVA), intraocular pressure, K max, symmetry index front, corneal thickness, and high order aberration findings were recorded. RESULTS: The study included 67 eyes of 67 patients with keratoconus: 39 in group 1, and 28 in group 2. There were statistically significant differences between the groups in the preoperative BCVA values (p=0.04). There was no significant difference between the preoperative and postoperative mean K max between the 2 groups (p=0.08). The mean difference in corneal thickness between preoperative and postoperative measurements was significantly lower in group 2 than in group 1 (p=0.03). The preoperative and postoperative mean spherical aberration was significantly higher in group 1 than in group 2 (p=0.001 and p=0.005, respectively). CONCLUSION: The preoperative cone location in keratoconus may affect CXL outcomes. At the end of the second year, CXL was found to have a similar efficacy on visual acuity and keratometry parameters in the central and paracentral cone groups, and the recovery in terms of a spherical aberration among high-order aberrations after CXL in the central cone group was better than that of the paracentral cone group.

Comparative study of small-incision lenticule extraction and phakic intraocular lens implantation for the correction of high myopia: 6-year results.

PURPOSE: To compare the long-term safety, efficacy, and complications of small-incision lenticule extraction (SMILE) and flexible iris-fixated anterior chamber phakic intraocular lens (pIOL) implantation for the treatment of high myopia. SETTING: University of Health Science Turkey, Beyoglu Eye Training and Research Hospital, Istanbul, Turkey. DESIGN: Retrospective comparative case series. METHODS: Data of patients who underwent SMILE or pIOL (Artiflex) implantation for myopia were retrospectively reviewed. Only patients with preoperative manifest refraction spherical equivalent from -6.00 to -10.00 diopters (D) were included in the study. RESULTS: There were 47 eyes of 32 patients in the SMILE group and 52 eyes of 29 patients in the pIOL group. The mean postoperative follow-up was 63.75 ± 18.40 months in the SMILE group and 65.38 ± 16.22 months in the p-IOL group (P = .71). At 6 years postoperatively, refractive predictability was slightly better in the pIOL group, and the percentages of eyes within ±0.50 D of the attempted correction were 77% and 83% in the SMILE and pIOL groups, respectively. Although mean uncorrected distance visual acuity was comparable (SMILE, 0.12 ± 0.06 logarithm of the minimum angle of resolution [logMAR]; p-IOL, 0.09 ± 0.05 logMAR), the safety indices (1.08 ± 0.22 vs 1.11 ± 0.20; P = .02) and the efficacy indices (0.92 ± 0.24 vs 1.11 ± 0.22; P = .03) were statistically significantly higher after pIOL implantation. Despite a mean of 11.09% of the endothelial cell being lost at 6 years after pIOL implantation, no pIOL was explanted due to endothelial cell loss. CONCLUSIONS: In this comparative and long-term study, iris-fixated anterior chamber pIOL implantation for high myopic correction showed slightly better safety and efficacy profiles but with statistically significant endothelial cell loss.

Repeatability and reliability of measurements obtained by the combined Scheimpflug and Placido-disk tomography in different stages of keratoconus.

OBJECTIVE: The objective of this study is to evaluate the repeatability and reliability of corneal parameters in different stages of keratoconus patients using a combined Scheimpflug-Placido disc analysis system. MATERIALS AND METHODS: In this prospective study, three consecutive measurements were performed by the same observer using Scheimpflug-Placido disc anterior segment analysis device in keratoconus patients. Flattest and steepest simulated keratometry and corneal volume, corneal aberrations, thinnest corneal thickness, symmetry index, keratoconus vertex and Baiocchi-Calossi-Versaci index were recorded. Keratoconic eyes were divided into four stages using the Amsler-Krumeich classification. Repeatability was evaluated using within the subject standard deviation, repeatability index (Ri) and coefficient of variation; reliability was evaluated by intraclass correlation coefficient (ICC). Pearson correlation coefficients were used to assess the correlation between the parameters evaluated. RESULTS: Two hundred sixty-one eyes of 261 keratoconus patients were included in the study. The repeatability for all corneal curvature parameters decreased as the keratoconus severity increased, and there is a positive correlation between keratometry of the apex and corneal curvature parameters (p < 0.05) except mean simulated keratometry. The corneal aberrations were repeatable in all keratoconus subgroups (Ri < 0.34 µm). There are also positive correlations between keratometry of apex and corneal aberrations (p < 0.05) except total high-order root mean square and spherical aberration. The reliability was excellent (ICC > 0.90) for all indices except keratoconus vertex back. CONCLUSION: The parameters used in the diagnosis and follow-up of keratoconus in the Sirius corneal tomography system may differ more than expected at stages 3 and 4 of the disease. Awareness of this situation may be helpful in planning follow-up and treatment.