Accuracy assessment of artificial intelligence IOL calculation formulae: utilizing the heteroscedastic statistics and the Eyetemis Analysis Tool.

OBJECTIVES: To analyse the accuracy of artificial intelligence (AI)-driven intraocular (IOL) calculation formulae, together with established formulae using the heteroscedastic methodology and the Eyetemis Analysis Tool. METHODS: Data from 404 eyes who underwent uneventful phacoemulsification with implantation of the SN60WF IOL were retrospectively reviewed. IOL power calculations were performed using the Barrett Universal II (BUII), EVO 2.0, Hoffer QST, K6, Ladas Super Formula (LSF), Nallasamy, PEARL-DGS and RBF 3.0 formulae. The SD of the prediction error (PE), served as the primary metric for accuracy. The mean absolute deviation (MAD) and the predictability rates within intervals from ±0.25 D to ±1.50 D were also evaluated. The Eyetemis Analysis Tool was used for further validation. RESULTS: The SD ranged from 0.468 (Nallasamy) to 0.510 (LSF). The Nallasamy formula had a significantly lower SD than the BUII (0.505, p = 0.025) and K6 (0.489, p = 0.022) formulae. The Nallasamy formula also exhibited the lowest MAD (0.358) with a significant difference compared with the Hoffer QST formula (0.384, p < 0.001). Finally, a significantly higher percentage of eyes achieving ± 0.50 D of the target refraction was seen using the Nallasamy formula (77.19%) compared with the Hoffer QST (71.04%, p = 0.019) and Ladas Super Formula (70.79%, p = 0.030) formulae. CONCLUSIONS: The Nallasamy formula, incorporating AI technology, demonstrated superior accuracy according to the analysis guidelines for PE statistics for non-gaussian datasets recommended by Holladay et al. and the online Eyetemis Analysis Tool.

Use of a silicone shield to protect the optical cylinder following osteo- and osteo-odonto-keratoprosthesis (O/OKP) procedures.

PURPOSE: To describe the placement of a silicone shield to protect the optical cylinder following osteo-keratoprosthesis or osteo-odonto-keratoprosthesis (O/OKP) procedures in four patients. METHODS: In this retrospective observational study, we reviewed all patients who underwent O/OKP in our tertiary medical centre. We found four patients in whom a protective cellphone silicone shield (VisionGuard+, Zagg, Utah, USA) was cut with a 3 mm dermal punch and placed on the polymethyl methacrylate (PMMA) optical cylinder of an O/OKP 3-4 months after implantation to either correct or prevent abrasions. RESULTS: The first patient presented with a severely abraded OOKP optic that reduced BCVA from 6/6 to 6/20. The shield smoothed the optical surface and filled minor scratches, leading to BCVA improvement to 6/9. In the subsequent three patients, the optic was relatively clear, and the shield was used as a preventive measure. In two patients, the shield fell off after a few weeks and was replaced. CONCLUSIONS: Placing a protective silicone shield on the optical cylinder of an O/OKP can prevent permanent abrasions and, in an already scratched polymethyl methacrylate (PMMA) optic cylinder, improve vision by smoothing the surface. This intervention can be clinically significant, considering that the optical cylinder cannot be removed after implantation.

Machine Learning-Based Identification of Risk Factors of Keratoconus Progression Using Raw Corneal Tomography Data.

PURPOSE: The purpose of this study was to identify early indicators of keratoconus progression in Pentacam data using machine learning (ML) techniques. METHODS: A retrospective Pentacam tabular data set was created by retrieving 11,760 tomography tests performed in patients with keratoconus. Data for eyes labeled unstable based on their referral for cross-linking were differentiated from data for eyes labeled stable and not referred for follow-up procedures. A boosted decision tree was trained on the final data set using a cross-validation method. RESULTS: The final labeled data set included 1218 tomography tests. Training a ML model on a single test for each eye did not accurately predict disease progression, as indicated by the mean receiver-operating characteristic area under the curve of 0.59 ± 0.1, with precision of 0.27, recall of 0.3, and F1 score of 0.28. Training on serial tests for each eye included 819 tomography scans and yielded good prognostic abilities: a receiver-operating characteristic area under the curve of 0.75 ± 0.07, precision of 0.32, recall of 0.67, and F1 score of 0.43. In addition, 4 of the 55 Pentacam raw data parameters predominantly used the algorithm decision: age, central keratoconus index, Rs B, and D10 mm pachy. CONCLUSIONS: This study revealed specific dominant parameters attributing to the classification of stability, which are not routinely assessed in determining progression in common practice. Using ML techniques, keratoconus deterioration was evaluated algorithmically with training on multiple tests, yet was not predicted by a single tomography test. Hence, our study highlights novel factors to the current consideration of cross-linking referral and may serve as a supportive tool for clinicians.

[ARTIFICIAL CORNEA: FROM THE BEGINNING TO THE FUTURE].

INTRODUCTION: Corneal disease is among the leading reversible causes of blindness worldwide. Corneal transplantation is a successful and curative treatment for most of these cases. However, in certain indications it is not amendable for standard corneal transplantation, the only available option to restore functional vision is keratoprosthesis (KPro) implantation. KPros may also offer an alternative to the global shortage of donor corneas, limiting the access to transplantations. However, current KPros face many challenges, including surgical complexity that requires skilled surgeons and vast resources as well as unique surgical and post-operative complications. Although several artificial corneas have been proposed over the years, two implants are mostly used in the clinical setting today. The first, the Boston KPro, consists of a front plate with an optical stem and a back plate snapped together with donor corneal tissue in-between, which is then sutured to the patient's cornea. The second, the Osteo-odonto-keratoprosthesis (OOKP), uses biological tissue of the alveolar bone to support an optical cylinder within the eye. The indications, surgical techniques, and complication profile of the two procedures are different and will be discussed in this review. Extensive research continues to improve the accessibility and technological developments of KPros in the search for a potential breakthrough in the treatment of these difficult cases.

Efficacy comparison of combining cross-linking and refractive laser ablation in progressive keratoconus: systematic review and meta-analysis.

OBJECTIVE: This study assessed the effect of combining corneal collagen cross-linking (CXL) with refractive laser ablation techniques for the treatment of keratoconus, a progressive corneal disorder. METHODS: We performed a systematic review and meta-analysis to assess the effect of combined CXL and refractive techniques. We included all published clinical trials or observational studies published by September 1, 2023. We calculated and compared the standardized mean difference (SMD) between CXL alone and CXL plus laser ablation for uncorrected distance visual acuity, best-corrected distance visual acuity, spherical equivalent manifest refraction, sphere and cylinder, flat keratometry (K1), steep keratometry (K2), and central corneal thickness. RESULTS: We identified 13 studies that fulfilled our inclusion and exclusion criteria. The average follow-up was 21.3 ± 11.8 months. The CXL plus laser ablation group showed improvement in uncorrected distance visual acuity logMAR (SMD, -0.35; 95% CI, -0.67 to -0.04; p = 0.029), best-corrected distance visual acuity logMAR (SMD, -0.17; 95% CI, -0.30 to -0.03; p = 0.014), spherical equivalent manifest refraction (SMD, -0.28; 95% CI, 0.06-0.50; p = 0.013), and change in maximal corneal curvature (Kmax; SMD, -0.41; 95% CI, -0.69 to -0.13; p = 0.004) compared with CXL alone. However, central corneal thickness decreased further among patients who underwent CXL plus laser ablation (SMD, -0.37; 95% CI, -0.66 to -0.07; p = 0.016). No effect was observed in terms of sphere (p = 0.878), cylinder (p = 0.859), K1 (p = 0.907), or K2 (p = 0.169). Ectasia was not observed as an adverse effect resulting from the additional corneal ablation performed during the CXL treatments. CONCLUSIONS: This study showed that combining refractive laser ablation techniques with standard or accelerated CXL treatment improved visual and refractive outcomes and anterior corneal curvature values.

Corneal pseudoectasia: a case series.

OBJECTIVE: To raise awareness of conditions that can tomographically mimic corneal ectasia and describe the actions required to avoid misdiagnosis. METHODS: We report a retrospective case series of seven patients presenting at two tertiary care centers in Israel with a presumed diagnosis of keratoconus or post-refractive ectasia. Upon further examination, the ectasia diagnosis was reconsidered and eventually ruled out. RESULTS: Included were ten eyes of seven patients. Cases included bilateral diffuse Salzmann's nodular degeneration, ophthalmoplegia with strabismus which precluded proper fixation during the acquisition of tomography images, two cases of incorrect Pentacam parameter settings, a patient with a history of hyperopic laser-assisted in situ keratomileusis (LASIK) treatment in one eye and myopic LASIK in the fellow eye, a case of old post-photorefractive keratectomy (PRK) stromal haze, and a patient with posterior polymorphous corneal dystrophy. CONCLUSIONS: Tomography patterns mimicking corneal ectasia can appear in patients without ectatic pathology. The comprehensive ophthalmologist should be aware of such cases as they may substantially alter the treatment course and prognosis of these patients.

Axial length and pharmacologic pupillary dilation in highly myopic patients.

PURPOSE: To determine how high myopia impacts pharmacological pupillary dilation, and to evaluate the relationship between the extent of pharmacologic pupillary dilation and axial length. METHODS: Patients were grouped into high myopes, defined as one or both eyes having a refractive error greater than - 6 diopters, and controls (between - 2 and + 2 diopters). Dilation was achieved with 1 drop each of tropicamide 1% and phenylephrine 2.5%. Pupil size was measured at full and dim light prior to dilation, then 15 and 30 min after dilation. Biometry was measured for each patient. Statistical analyses were performed using the Mann-Whitney-Wilcoxon tests, two-sample Welch's t-tests, and linear mixed effect models and generalized estimating equations models accounting for inter-eye correlation. RESULTS: Forty patients (20 high myopes and 20 controls, 80 eyes total) participated in the study. High myopes had larger pupils at baseline and achieved significantly greater pupillary size (7.08 mm, 95% CI: 6.97 to 7.19 mm) than controls (6.23 mm, 95% CI: 5.94 to 6.52 mm) after 30 min of dilation (P < .0005). Fully dilated pupil size at 30 min was significantly correlated with both refractive error (r = - 0.57, P < .0005) and axial length (r = 0.47, P < .0005). Generalized estimating equations and linear mixed effect models identified other predictive variables of pupil size after dilation including age and white-to-white diameter. CONCLUSIONS: Highly myopic patients dilate to a larger pupillary size compared to other patients. Predicting dilation based on extent of myopia could facilitate intraocular surgery planning and reduce clinic wait times for myopic patients.

Long-Term Evaluation of Pseudoexfoliation Syndrome Post-Cataract Extraction.

The study aimed to examine the effect of cataract extraction on ophthalmologists' ability to detect pseudoexfoliation (PXF) syndrome. A total of 31 patients admitted for elective cataract surgery were enrolled in this prospective comparative study. Prior to surgery, patients underwent slit-lamp examination and gonioscopy conducted by experienced glaucoma specialists. Subsequently, patients were re-examined by a different glaucoma specialist and comprehensive ophthalmologists. Pre-operatively, 12 patients were diagnosed with PXF on the basis of a Sampaolesi line (100%), anterior capsular deposits (83%), and pupillary ruff deposits (50%). The remaining 19 patients acted as controls. All patients were re-examined 10-46 months post-operatively. Of the 12 patients with PXF, 10 (83%) were correctly diagnosed post-operatively by glaucoma specialists and 8 (66%) by comprehensive ophthalmologists. There was no statistically significant difference in PXF diagnosis. However, detection of anterior capsular deposits (p = 0.02), Sampaolesi lines (p = 0.04), and pupillary ruff deposits (p = 0.01) were significantly lower post-operatively. Diagnosis of PXF is challenging in pseudophakic patients as the anterior capsule is removed during cataract extraction. Therefore, PXF diagnosis in pseudophakic patients relies mainly on the presence of deposits at other anatomical sites, and careful attention to these signs is required. Glaucoma specialists may be more likely than comprehensive ophthalmologists to detect PXF in pseudophakic patients.

The first-in-human implantation of the CorNeat keratoprosthesis.

OBJECTIVES: To describe the first clinical implantation of the CorNeat™ keratoprosthesis, which utilizes a polymeric scaffold for biointegration within ocular tissue. METHODS: The CorNeat keratoprosthesis was implanted in the right eye of a patient with bilateral corneal opacification and neovascularization secondary to multiple failed grafts. The following surgical technique was used: 360 degree peritomy; epithelial scraping and corneal marking; pre-placement of three corneo-scleral sutures through the implant; central trephination using a 7 mm trephine and host cornea removal; keratoprosthesis placement and sutures tightening while fitting the corneal edge into the posterior groove of the CorNeat keratoprosthesis; and repositioning of the conjunctiva over the implant skirt and fixation with sutures and Fibrin sealant. RESULTS: Twelve months postoperatively visual acuity improved to 1/16 from hand movement. The keratoprosthesis was properly positioned. Tactile intraocular pressure was assessed as normal. Regional, mostly nasal, conjunctival retraction of 4-5 mm over the nano-fibre skirt was seen throughout follow-up. The anterior chamber was quiet and well-formed. No other postoperative complications were observed. CONCLUSION: This initial case may imply a potential breakthrough in the treatment of corneal disease not amenable to standard corneal transplant. Long follow-up and additional implantations are desired to prove the long-term safety and efficacy of this device.

Post-refractive surgery of Israeli Defense Forces recruits in 2005-2018-prevalence, combat unit drop-out rates and utilization of eye-care services.

PURPOSE: To assess the number of recruits for military service in the Israeli Defense Force (IDF) who underwent refractive surgery prior to enlistment and examine whether the procedure affected their ability to accomplish combat training. SETTING: Medical records of IDF recruits. DESIGN: Retrospective analysis of medical records of recruits with ametropia who underwent or did not undergo refractive surgery prior to enlistment. METHODS: Recruits were categorized into ametropes and recruits who underwent refractive surgery. Fitness and assignment to combat units and completion status of combat training were compared between the two groups. RESULTS: The study included 334,688 (182,969 males, 151,719 females) ametropes of which 5231 (4753 males, 478 females) underwent refractive surgery prior to recruitment. Refractive surgery prevalence increased from 9/1000 ametropes in 2005 to 18.5/1000 ametropes in 2018 (r = 0.912, p < 0.001); 2643 of the operated recruits (50.5%) had their surgery at the age of 17-18. Dropout rates from combat training were significantly lower in the refractive surgery group during the study period (1.68% vs. 6.14%, respectively, p < 0.001). Soldiers in the operated group were more frequently referred to ophthalmologists than those in the ametropes group and less frequently referred to optometrists. CONCLUSIONS: The prevalence of refractive surgery in IDF recruits has increased substantially during the last decade with more of them applying to combat units. Refractive surgery opened new possibilities for recruits who were unfit for combat duty prior to surgery and did not appear to impair the chances of successfully completing combat training.

ABCD progression display for keratoconus progression: a sensitivity-specificity study.

OBJECTIVE: To evaluate the sensitivity and specificity of the ABCD progression display for keratoconus progression. METHODS: Data was collected from patients that underwent at least two Pentacam assessments 6 months apart. Sensitivity and specificity were calculated for the ABCD progression display. Progression was defined by criterion 1: change in two ABCD parameters above 80% confidence interval (CI) or criterion 2: change in one ABCD parameter above 95%CI. Receiver operating characteristic analysis compared the area under the curve (AUC) of all ABCD parameter combinations. RESULTS: Thirty eyes were evaluated over a median time of 10.3 months. Progression by criterion 1 resulted in a sensitivity of 61.9% and specificity of 88.9%. Progression by criterion 2 resulted in higher sensitivity (80.9%) and specificity (100%). Pairwise comparisons of the ROC curves show that the AUC achieved by criterion 2 was significantly higher than criterion 1 (0.905 vs. 0.754, p = 0.0332). Evaluation of all ABCD combinations with a significant change of 80% or 95% CI did not show superiority over criterion 1 or 2 regarding progression detection. The D parameter had a very low AUC (0.5-0.556). CONCLUSIONS: The ABCD progression display can assess keratoconus progression with high sensitivity and specificity, thus assisting the patients' decision-making process. The D parameter did not contribute to the sensitivity or specificity of this classification.

Validation of the multi-metric D-index change in the assessment of keratoconus progression.

PURPOSE: To validate the effectiveness of the multi-metric D-index by Pentacam in detecting keratoconus (KC) progression. MATERIALS AND METHODS: This was a retrospective study of KC patients at the Rabin Medical Center, Petah Tikva, Israel, during 2016-2018 with at least two corneal tomography examinations six months apart. Agreement between clinical diagnosis of progression (1.5D increase in mean keratometric value, 1D increase in Kmax, a 5% decrease in central corneal thickness (CCT), worsening of visual acuity by more than one line, or deterioration of manifest corneal astigmatism > 1.5D) and the D-index was evaluated. Receiver operating characteristic (ROC) analysis was used to find the D-index's optimal cutoff value to show progression. RESULTS: We included KC eyes in the stable group (N = 7) and the progression group (N = 54). Patient demographics and tomographic parameters at baseline were similar between the groups. The D-index change was significantly higher in the progression group than in the stable group (median + 1 and 0.0, respectively, p = 0.024). Based on the ROC analysis, the optimal D-index cutoff change within at least six months was 0.32 (59.3% sensitivity and 100% specificity (area under the curve [AUC] = 0.771, Youden = 0.592). Subjects with a D-index change above this value had a 21.1-fold increase in odds for corneal ectasia progression requiring CXL (OR: 21.1, 95%CI 1.17-398.8, p = 0.038). CONCLUSION: The multi-metric D-index can serve as a clinically feasible parameter to detect KC progression and guide patients' referral for further interventions.

Effect of Descemet Membrane Endothelial Keratoplasty Graft Storage Time on Graft Elasticity.

PURPOSE: The purpose of this study was to evaluate the effect of Descemet membrane endothelial keratoplasty (DMEK) graft storage time on its elastic properties, measured using atomic force microscopy (AFM). METHODS: Twenty human corneas (from 10 donors), unsuitable for transplantation, were obtained from the eye bank (S. Fyodorov Eye Microsurgery State Institution, Moscow). Ten DMEK grafts were prepared and stored in the corneal storage medium, Optisol-GS at 4°C after preparation, and AFM analysis was performed within 12 hours after preparation (group A). Ten paired corneas from the respective donors were stored in Optisol-GS at 4°C for 1 week after preparation before AFM analysis (group B). Data were analyzed using the Hertz model for the evaluation of the Young modulus of elasticity. RESULTS: Force-distance curve analysis showed an increase in the Young modulus of elasticity in group B in comparison with that in group A, and the mean values were 10.4 ± 1.8 kPa and 6.77 ± 2.25 kPa, respectively (P < 0.001). There was no correlation between the Young modulus of elasticity and donor age (r = 0.110, P = 0.644), endothelial cell count (r = -0.145, P = 0.541), and procurement interval (r = 0.14, P = 0.755). CONCLUSIONS: A longer graft storage time in cold storage medium was found to significantly reduce the elasticity of the DMEK graft. Clinically, this could potentially influence the unfolding of the DMEK graft within the anterior chamber during surgery and the postoperative detachment rate.

Transepithelial photorefractive keratectomy on the same day of the initial consultation for the correction of myopia.

PURPOSE: To examine the clinical outcomes, efficacy, safety, and predictability of transepithelial photorefractive keratectomy (Trans-PRK) operations performed on the day of the first screening visit in comparison with operations scheduled at a following appointment. METHODS: Data of consecutive patients with myopia of various degrees, who underwent Trans-PRK, were retrospectively analyzed. Findings were compared between patients who underwent Trans-PRK on the same day of first consultation to patients that underwent surgery at subsequent visits, following initial consultation on a different day. RESULTS: The study included 599 eyes treated on the initial visit day and 1936 eyes treated on a subsequent visit. Mean final spherical equivalent was close to emmetropia in both groups (p = 0.183). Efficacy indices were 0.928 ± 0.192 in the initial-visit group and 0.945 ± 0.163 in the second-visit group (p = 0.152). Safety indices were 0.954 ± 0.156 and 0.955 ± 0.151 (p = 0.707), respectively. No differences between the groups were seen in uncorrected visual acuity (UDVA) of ⩾20/20, ⩾20/25, and ⩾20/32. Only the sub-analysis of patients reaching UDVA of 20/40 or better was slightly lower in the first-visit (95.5%) compared with the second-visit group (97.9%, p = 0.001). Results of attempted correction within ±0.50 D were: 63.3% and 69.0%, respectively (p = 0.009). Complications profiles in the two groups were comparable. CONCLUSIONS: Trans-PRK completed on the day of the first screening appointment demonstrated a similar safety outcome compared with subsequent-visits procedures, and slightly lower, yet comparable, results regarding efficacy and predictability.

Outcomes of Repair of Total Graft Detachment following Descemet's Membrane Endothelial Keratoplasty. / Rettungsversuche einer vollständigen Transplantatablösung nach Descemet-Membran-Endothelkeratoplastik.

OBJECTIVE: To present the outcomes of attempts to salvage total graft detachment following Descemet's membrane endothelial keratoplasty (DMEK). METHODS: A search of the electronic medical records of two tertiary medical centers for all patients who underwent DMEK yielded six cases of postoperative total graft detachment (2.54%). Graft salvage was attempted in all cases using repeated intracameral graft staining, unfolding, and reattachment to the stroma under 20% hexafluoride gas. RESULTS: In all cases, a free-floating totally detached graft was identified in the anterior chamber shortly after surgery. Salvage surgery resulted in a central, well-oriented, and fully attached graft. In three cases, the primary graft failed, and in two, the corneas cleared at first but failed after 2 months and 1 year respectively. In one case, the cornea remained clear during 1 year of follow-up but had a very low endothelial cell density. CONCLUSION: Reattachment of fully detached DMEK graft is technically possible, but graft manipulation during the primary and secondary operations is likely to damage the endothelial cells, resulting in primary or early graft failure. If graft salvage is attempted, the probability of primary or early graft failure should be discussed with the patient, and expectations should be tempered accordingly.

New Horizons in the Treatment of Corneal Endothelial Dysfunction.

The treatment of corneal endothelial dysfunction has experienced a revolutionary change in the past decades with the emergence of endothelial keratoplasty techniques: descemet stripping automated endothelial keratoplasty (DSAEK) and descemet membrane endothelial keratoplasty (DMEK). Recently, new treatments such as cultivated endothelial cell therapy, Rho-kinase inhibitors (ROCK inhibitors), bioengineered grafts, and gene therapy have been described. These techniques represent new lines of treatment for endothelial dysfunction. Their advantages are to help address the shortage of quality endothelial tissue, decrease the complications associated with tissue rejection, and reduce the burden of postoperative care following transplantation. Although further randomized clinical trials are required to validate these findings and prove the long-term efficacy of the treatments, the positive outcomes in preliminary clinical studies are a stepping stone to a promising future. Our aim is to review the latest available alternatives and advancements to endothelial corneal transplant.

Descemet Membrane Endothelial Keratoplasty in Eyes With Chronic Ocular Hypotony Following Glaucoma Surgery.

PURPOSE: To assess the outcomes of Descemet membrane endothelial keratoplasty (DMEK) in patients with ocular hypotony after glaucoma surgery. DESIGN: retrospective case series. METHODS: Setting: Multicenter retrospective case series. PATIENTS/INTERVENTION: Hypotonic eyes with prior glaucoma surgery that underwent DMEK between January 2013 and July 2019 in Israel (2 centers) and Canada (1 center). MAIN OUTCOME MEASURES: Pre/postoperative corrected distance visual acuity, complications, 3- to 6-month endothelial cell loss, and intraocular pressure (IOP). RESULTS: The study included 11 DMEK procedures performed in 10 eyes of 4 males and 6 females aged 65-84 years. Indications for DMEK included 7 cases of pseudophakic bullous keratopathy, 2 cases of failed DMEK, and 1 case of failed Descemet stripping automated endothelial keratoplasty. All patients had at least 1 previous trabeculectomy operation. One patient had 2 trabeculectomy procedures and 1 tube placement procedure. Two patients had 1 previous trabeculectomy and 1 tube placement procedure. The corrected distance visual acuity improved significantly from 1.52 ± 0.68 logarithm of minimal angle of resolution preoperatively to 0.49 ± 0.32 logarithm of minimal angle of resolution 3 months postoperatively (P < .001). Rebubbling occurred in 3 of 11 procedures (27%). Endothelial cell loss 6-12 months postoperatively was 60% ± 16% (range, 41%-89%). At the last follow-up visit, 6 of 11 (54%) of the grafts were clear. The remaining 5 grafts failed at 1-4 years postoperatively. The preoperative IOP was 5.1 ± 1.6 mm Hg (range, 1-7 mm Hg). In all but one patient, the postoperative IOP did not increase to more than 13 mm Hg. In 2 cases, the IOP decreased from 5 and 7 mm Hg preoperatively to 1 mm Hg 1 year postoperatively. CONCLUSION: DMEK is a valid procedure for the treatment of corneal edema in hypotonic eyes after glaucoma procedures. These eyes benefit from improvement in vision after DMEK.

Descemet Membrane Endothelial Keratoplasty Outcomes between Young and Old Graft Recipients.

Purpose: To evaluated Descemet's membrane endothelial keratoplasty (DMEK) outcomes in young and old graft recipients.Materials and Methods: Data of 164 surgeries with a median age of 76 years (interquartile range 14 years) undergoing DMEK surgery between 2016 and 2018 was reviewed. Complications, graft survival, and visual acuity gain were compared between subjects in the 25th percentile (young recipients; aged 70 years and less, n = 21) and 75th percentile (old recipients; aged 85 years and over, n = 27) over the 2-year follow-up.Results: Young recipients had a lower rate of pre-operative glaucoma (14.3% vs. 51.9%, p = .014) and pseudophakic bullous keratopathy (9.5% vs. 59.3%, p < .001), and a higher rate of Fuchs endothelial dystrophy (57.1% vs. 14.8%, p = .002) and combined cataract extraction at the time of DMEK surgery (52.4% vs. 7.4%, p = .001) when compared to old recipients. Complications (primary graft failure, pupillary block, cystoid macular edema or infectious keratitis) were independent of graft recipient age. Descemet's membrane detachment requiring re-bubbling was observed more often in young compared to the old recipients (42.9% vs. 14.8%, p = .049). Visual acuity gain between the groups remained comparable up to 1-year, whereas at 2-years old recipients showed significantly declined visual acuity gains compared to the young recipients (0.14 ± 0.68 vs. 0.74 ± 0.49, p = .012). Graft recipients aged over 85 years had a considerably higher graft failure rate over the 24-months (40.7% vs. 4.8%, p = .006) and shorter graft survival time (p = .002; log-rank) when compared to the recipients aged under 70 years. After adjusting for potential confounders such as Fuchs endothelial dystrophy, pseudophakic bullous keratopathy and glaucoma, the recipients aged over 85 remained at higher risk for graft failure (HR = 17.278, 95% CI = 1.787-167.1, p = .014).Conclusions: In aged DMEK recipients, regardless of the low incidence of early postoperative complications, the rate of postoperative graft failure was significantly higher and graft survival shorter than in younger recipients.

Effect of Penetration Angle and Velocity During Intravitreal Injection on Pain.

Purpose: To evaluate the effect of velocity and angle of the intravitreal injection of anti-vascular endothelial growth factors on pain sensation.Methods: Patients were randomly assigned to one of four injection methods: straight and fast, straight and slow, tunneled and fast, and tunneled and slow. Later, they graded their pain sensation on a Visual Analog Scale (range 0-10).Results: The cohort included 180 patients. Mean pain score was 2.81 ± 2.34. There was no statistically significant difference in mean pain score among the four groups (p = .858); between the slow-injection (straight and tunneled) and fast-injection groups (p = .514); and between the straight-injection (fast and slow) and tunneled-injection groups (p = .992), nor other background variables.Conclusion: Velocity and angle of intravitreal injections are unrelated to the pain sensation. Therefore, the method may be left to the clinician's discretion. This implies that the sensation is mostly subjective.