The effect of hyperbaric oxygen therapy on corneal endothelial structure and anterior segment parameters

PURPOSE

To assess the effect of hyperbaric oxygen therapy (HBOT) on corneal endothelial structure and anterior segment parameters in healthy eyes.

METHODS

17 eyes of 17 patients who were scheduled to receive HBOT for other than ophthalmologic indications were investigated in this prospective study. Central corneal thickness (CCT) and corneal endothelial properties were evaluated using a specular microscope. Endothelial cell density (ECD), average cell area (AVG), coefficient of variation in cell size (CV), percentage of hexagonal cells (HEX), CCT, intraocular pressure (IOP), spherical equivalent (SE), axial length (AL) and anterior chamber depth (ACD) values were measured before the HBOT, after the 1st session, and after the 20th session of therapy.

RESULTS

47% of the patients (n = 8) received HBOT because of avascular necrosis, 35% (n = 6) due to sudden hearing loss, 12% (n = 2) for diabetic foot, and 6% (n = 1) for wound infection. The mean IOP was 14,80 mmHg before HBOT, 14,20 mmHg after the 1st session, and 13,73 mmHg after the 20th session. The mean ACD was 3,38 mm before HBOT, 3,34 mm after the 1st session, and 3,16 mm after the 20th session. Although the mean IOP and ACD decreased after HBOT sessions, it was not statistically significant (p > 0.05). A significant reduction was observed in SE values after 20 sessions of HBOT compared to the values measured before HBOT (p = 0,009). The mean ECD was 2572,53 ± 261,51 cells/mm2 before HBOT, 2554,47 ± 236,13 after the 1st session, and 2563,13 ± 226,92 after the 20th session. When the corneal properties measured before and after HBOT sessions were compared, no significant difference was found in terms of CCT, ECD, AVG, CV, and HEX (p > 0.05).

CONCLUSION

We observed no significant change in CCT, corneal endothelial layer properties, and anterior segment morphology after the 1st session, and after the 20th session of HBOT. Although HBOT reduced IOP and ACD, it was not statistically significant. HBOT may lead to a significant decrease in SE values after the 20th session.

Morphology and thickness of corneal endothelial cells in young Sudanese individuals with myopia

Deviations in corneal endothelium morphology and thickness may indicate corneal abnormalities and could be associated with myopia development. This study aimed to evaluate corneal endothelial cell morphology and central corneal thickness in young individuals with myopia. A prospective study was conducted at Al-Neelain University Eye Hospital between January 2019 and January 2020, including 160 patients with myopia (320 eyes). Data was gathered through clinical assessment of visual acuity, refractive error, and corneal endothelial cells. Results showed that 60% of participants with myopia were female, with a mean age of 21.99±2.8 years and a mean equivalent sphere of -3.19±2.67D. There was a significant difference in endothelial cell degeneration between myopia groups (P<0.001). Corneal guttata occurred in 9.1% of eyes with low myopia and 68.2% with moderate myopia, whereas polymegathism and polymorphism were more prevalent in high myopia. The mean central corneal thickness was 500.50±38.94 µm in low myopia, 497.02±36.23 µm in moderate myopia, and 477.87±43.625 µm in high myopia (P=0.007). The mean endothelial cell number in low myopia was 107.86±21.12, 106.0±24.03 in moderate myopia, and 101.23±18.49 in high myopia (P<0.05). The mean difference in endothelial cell density, coefficient of variation, and hexagonality in low, moderate, and high myopia was not significant (P>0.05). However, Pearson's correlation revealed a significant negative correlation between the degree of myopia and central corneal thickness (r= -0.174, P=0.002) as well as endothelial cell number (r= -0.124, P=0.026). The study concluded that central corneal thickness and endothelial cell number significantly decreased with an increase in the degree of myopia. Corneal guttata was the most common form of endothelial cell degeneration observed in cases of high myopia.

Particular Anatomy of the Hyperopic Eye and Potential Clinical Implications

Background and Objectives: Hyperopia is a refractive error which affects cognitive and social development if uncorrected and raises the risk of primary angle-closure glaucoma (PACG). Materials and Methods: The study included only the right eye-40 hyperopic eyes in the study group (spherical equivalent (SE) under pharmacological cycloplegia over 0.50 D), 34 emmetropic eyes in the control group (SE between -0.50 D and +0.50 D). A complete ophthalmological evaluation was performed, including autorefractometry to measure SE, and additionally we performed Ocular Response Analyser: Corneal Hysteresis (CH), Corneal Resistance Factor (CRF); specular microscopy: Endothelial cell density (CD), Cell variability (CV), Hexagonality (Hex), Aladdin biometry: Anterior Chamber Depth (ACD), Axial Length (AL), Central Corneal Thickness (CCT). IBM SPSS 26 was used for statistical analysis. Results: The mean age of the entire cohort was 22.93 years (SD ± 12.069), 66.22% being female and 33.78% male. The hyperopic eyes had significantly lower AL, ACD, higher SE, CH, CRF. In the hyperopia group, there are significant, negative correlations between CH and AL (r -0.335), CRF and AL (r -0.334), SE-AL (r -0.593), ACD and CV (r -0.528), CV and CRF (r -0.438), CH (r -0.379), and positive correlations between CCT and CH (r 0.393) or CRF (r 0.435), CD and ACD (r 0.509) or CH (0.384). Age is significantly, negatively correlated with ACD (r -0.447), CH (r -0.544), CRF (r -0.539), CD (r -0.546) and positively with CV (r 0.470). Conclusions: Our study suggests a particular biomechanical behavior of the cornea in hyperopia, in relation with morphological and endothelial parameters. Moreover, the negative correlation between age and ACD suggests a shallower anterior chamber as patients age, increasing the risk for PACG.

Diagnostic Techniques to Increase the Safety of Phakic Intraocular Lenses

Preoperative and postoperative diagnostics play an important role in ensuring the safety of patients with phakic intraocular lenses (pIOLs). The risk of endothelial cell loss can be addressed by regularly measuring the endothelial cell density using specular microscopy and considering the endothelial cell loss rate and the endothelial reserve in accordance with the patient's age when deciding whether to explant a pIOL. The anterior chamber morphometrics, including the anterior chamber depth and the distance between the pIOL and the endothelium, measured using Scheimpflug tomography and anterior segment optical coherence tomography (AS-OCT), can help to assess the risk of the endothelial cell loss. In patients undergoing posterior chamber pIOL implantation, accurate prediction of the vault and its postoperative measurements using AS-OCT or Scheimpflug tomography are important when assessing the risk of anterior subcapsular cataract and secondary glaucoma. Novel approaches based on ultrasound biomicroscopy and AS-OCT have been proposed to increase the vault prediction accuracy and to identify eyes in which prediction errors are more likely. Careful patient selection and regular postoperative follow-up visits can reduce the complication risk and enable early intervention if a complication occurs.

Corneal Outcomes Following Cataract Surgery Using Ophthalmic Viscosurgical Devices Composed of Chondroitin Sulfate-Hyaluronic Acid: A Systematic Review and Meta-Analysis

Background

Ophthalmic viscosurgical devices (OVDs) are commonly used during cataract surgery to protect the corneal endothelium. A systematic literature review and meta-analysis were conducted to assess the clinical evidence of OVDs composed of chondroitin sulfate-hyaluronic acid (CS-HA) versus other OVDs in maintaining endothelial cell density (ECD) and corneal thickness (CT).

Methods

MEDLINE and EMBASE databases were searched from 2000 to 2020. Randomized controlled trials (RCTs, N ≥ 20 per group) comparing an OVD containing CS-HA (ie, VISCOAT^®, DuoVisc^® or DisCoVisc^®) to any other OVD were included. The identified comparators were limited to the OVDs found in the literature, which included those composed of HA-only or hydroxypropyl methylcellulose (HPMC). Outcomes of focus included changes in ECD (baseline to 3 months) and CT (baseline to 24 hours). Meta-analyses were performed using R software, to assess mean differences (MD) in ECD and CT change between CS-HA OVDs and HA-only or HPMC OVDs.

Results

A total of 966 abstracts were screened, and data were extracted from 12 RCTs. Meta-analyses using a random-effects model revealed significantly lower percent (%) decrease in ECD for CS-HA OVDs compared to both HA-only (MD: -4.10%; 95% CI: -5.81 to -2.40; p < 0.0001; 9 studies) and HPMC (MD: -6.47%; 95% CI: -10.41 to -2.52; p = 0.001; 2 studies) products. Similarly, % CT increase was significantly lower with CS-HA than with HA-only OVDs (MD: -3.22%; 95% CI: -6.24% to -0.20%; p = 0.04; 4 studies). However, there were no significant differences when comparing % CT change between CS-HA and HPMC OVDs (MD: 2.65%; 95% CI: -0.43% to 0.95%; p = 0.4; 2 studies).

Conclusion

CS-HA OVDs lead to less postoperative loss of endothelial cells and may better protect corneal endothelium during cataract surgery, relative to other OVDs. Future randomized studies may be needed to solidify these findings.

Combined versus sequential penetrating keratoplasty and cataract surgery for herpes simplex keratitis: a retrospective study

Purpose

To compare the surgical outcomes of combined penetrating keratoplasty (PK) and cataract surgery with those of sequential surgery (cataract surgery after PK) for herpes simplex keratitis (HSK).

Methods

The medical records of consecutive patients diagnosed with HSK who underwent combined or sequential PK and cataract surgery in active and stable stages between June 2015 and June 2022 were reviewed retrospectively. Complications, graft survival, endothelial cell density (ECD), and final BCVA were compared and analyzed between both surgical methods in each stage.

Results

A total of 171 eyes of 171 patients were enrolled, including active stage (69 combined, 46 sequential) and stable stage (34 combined, 22 sequential). The average follow up was 24.2 ± 15.8 months (range, 3 months - 48 months). The final BCVA had obvious improvement and the postoperative ECD was not different in combined and sequential groups of each stage. In sequential group of active stage, 66.7% of persistent epithelial defects and 50% of HSK recurrence occurred within 3 months after cataract surgery; nevertheless, compared to that in sequential group, capsular rupture (p = 0.021), persistent epithelial defects (p = 0.027), and HSK recurrence (p = 0.035) occurred more frequently in combined group, leading to a lower graft survival rate (p = 0.045); at the last visit, 46.4 and 67.4% of grafts remained clear in combined and sequential groups, respectively. By contrary, 82.4 and 50.0% of grafts remained clear in stable stages of combined and sequential groups at the last visit, respectively, and a higher graft survival rate was observed in combined group (p = 0.030).

Conclusion

Although the postoperative ECD is not different between two surgical groups in each stage, sequential surgery in active stage of HSK seems to have advantages in less complications and higher graft survival rate, whereas combined surgery in stable stage has a better outcome than that in sequential surgery.

Destructive effects on endothelial cells of grafts in cytomegalovirus DNA-positive patients after keratoplasty

AIM

To investigate corneal graft survival rate and endothelial cell density (ECD) loss after keratoplasty in cytomegalovirus (CMV) positive patients.

METHODS

This was a retrospective cohort study. We analyzed the clinical data of patients who underwent viral DNA detection in aqueous humor/corneal tissue collected during keratoplasty from March 2015 to December 2018 at the Peking University Third Hospital, Beijing, China. To further evaluate the effect of CMV on graft survival rate and ECD loss, patients were divided into three groups: 1) CMV DNA positive (CMV+) group; 2) viral DNA negative (virus-) group, comprising virus- group eyes pairwise matched to eyes in the CMV+ group according to ocular comorbidities; 3) control group, comprising virus- group eyes without ocular comorbidities. The follow-up indicators including graft survival rate, ECD, ECD loss, and central corneal thickness (CCT), were analyzed by Tukey honestly significant difference (HSD) test.

RESULTS

Each group included 29 cases. The graft survival rate in CMV+ group were lowest among the three groups (P=0.000). No significant difference in donor graft ECD was found among three groups (P=0.54). ECD in the CMV+ group was lower than the virus- group at 12 (P=0.009), and 24mo (P=0.002) after keratoplasties. Furthermore, ECD loss was higher in the CMV+ group than in the virus- group in the middle stage (6-12mo) post-keratoplasty (P=0.017), and significantly higher in the early stage (0-6mo) in the virus- group than in the control group (P=0.000).

CONCLUSION

CMV reduces the graft survival rate and exerts persistent detrimental effects on the ECD after keratoplasty. The graft ECD loss associate with CMV infection mainly occurrs in the middle stage (6-12mo postoperatively), while ocular comorbidities mainly affects ECD in the early stage (0-6mo postoperatively).

The Impact of Robotic Fractionated Radiotherapy for Benign Tumors of Parasellar Region on the Eye Structure and Function

PURPOSE

To evaluate the radiation effect of fractionated robotic radiotherapy of benign tumors located in the parasellar region on the anterior and posterior segments of the eye.

METHODS

A prospective observational study based on the expanded ophthalmological examination. The pre-treatment baseline was used as a control for the post-radiotherapy follow-up examinations. The study group consists of 34 patients (68 eyes) irradiated using the CyberKnife system. There were ten patients with cavernous sinus meningioma, nine with pituitary adenoma, five with meningioma of the anterior and middle cranial fossa, five with meningioma in the region close to optic chiasm, three with craniopharyngioma, and two with meningioma of the orbit. All patients were treated using three fractions of 600-800 cGy. We assessed the impact of radiation on the eye based on changes in anatomical and functional features. The condition of the eye surface, central corneal thickness (CCT), endothelial cell density (ECD), lens densitometry, central macular thickness (CMT), and retinal nerve fiber layer (RNFL) were the anatomical features assessed. The functional tests were best-corrected visual acuity (BCVA), intraocular pressure (IOP), visual field (VF) and visual-evoked potentials (VEP). An ophthalmologic examination was performed before and 6, 12, 18, and 24 months after radiotherapy.

RESULTS

We did not observe any significant changes in BCVA, IOP, CCT, CMT, VF, and VEP, nor in the slit-lamp examination during the two-years observation. We found a significant decrease in ECD at all follow-up measurements. The drop in ECD exceeded approximated age-related physiological loss. The reduction in ECD was not large enough to disrupt corneal function and thus affect vision. We also observed a statistically significant reduction of RNFL in all observation time points. However, there was no correlation between the dose delivered to the optic pathway and the decrease in RNFL thickness. The thinning of the RNFL was not significant enough to impair visual function.

CONCLUSION

Fractionated robotic radiotherapy of the tumors located close to the optical pathway is safe and does not impair patient's vision. Minor changes found in optic nerve anatomy (RNFL thinning) might be related to radiation effect or tumor compression. The causal relation between low doses of radiation delivered to the cornea and the observed significant but slight decrease in ECD is uncertain. The observed changes did not cause visual disturbances perceivable by the patients.

The safety and efficacy of phacoemulsification surgery in uncomplicated cataracts with and without an ophthalmic-viscosurgical-device

PURPOSE

To compare and evaluate the results of phacoemulsification surgery involving and not involving an ophthalmic-viscosurgical-device (OVD).

METHODS

A prospective, randomized controlled trial included 60 eyes of 60 patients scheduled to receive phacoemulsification surgery. In order of presentation, patients were randomized into two groups to undergo different surgical techniques: the OVD-free group (n = 30) and the OVD group (n = 30). Each patient's operating time, total ultrasonography (U/S) time, cumulative dissipated energy (CDE), aspiration time, and volume of balanced salt solution (BSS) aspirated were recorded. At 1 day, 1 week, and 1 and 3 months postoperation, measurements of endothelial cell density (ECD) and intraocular pressure (IOP), were taken and compared between the groups.

RESULTS

Total U/S time (p = .567) and CDE (p = .168) were similar between the groups. In the OVD group, operating time (p = .011), aspiration time (p < .001), and volume of BSS aspirated (p < .001) were greater than in the OVD-free group. The change in ECD between the groups was not statistically significant at all visits (p = .433, p = .147, p = .379, p = .534; respectively). Although IOP increased in the OVD group at 1 day postoperation (p = .001), no difference emerged between the groups at 3 months postoperation (p = .121).

CONCLUSION

Phacoemulsification surgery without an OVD took less time than with the OVD and caused no significant loss in ECD. Surgeons concerned about elevated IOP following cataract surgery should apply the OVD-free method.

Corneal endothelial changes following cataract surgery in hard nuclear cataract: Randomized trial comparing phacoemulsification to manual small-incision cataract surgery

Purpose

To evaluate and compare endothelial cell changes in phacoemulsification and manual small-incision cataract surgery (MSICS) in patients with uncomplicated senile cataracts.

Methods: This was a prospective

, tertiary care hospital-based, randomized, double-blinded interventional study. In total, 152 patients with an uncomplicated senile cataract of nuclear grade III and above were recruited. Exclusion criteria included patients with preoperative endothelial cell density (ECD) less than 1500 cells/mm³, a history of previous ocular surgery, any other coexisting ocular disease, and intraoperative or postoperative surgical complications. Preoperative and postoperative values of ECD and central corneal thickness (CCT) were measured, analyzed, and correlated with various factors.

Results

Patients were randomized into two interventional groups-MSICS and phacoemulsification. Factors associated with significant drop in postoperative ECD following phacoemulsification were patients with advanced age (P = 0.01), higher grades of cataract (P = 0.01), and longer effective phacoemulsification time (P = 0.007). Shallow anterior chamber depth (ACD) was strongly associated with greater ECD loss in both groups (P < 0.0001). A threshold value of 2.86 mm of ACD was defined for minimal endothelial cell loss following phacoemulsification. CCT was observed to slightly increase postoperatively in both groups but was insignificant (P > 0.05).

Conclusion

Both MSICS and phacoemulsification have similar postoperative visual outcomes. An increase in postoperative CCT is insignificant following surgery. Greater postoperative ECD loss is associated with phacoemulsification with advanced age, hard nuclear cataracts, and longer effective phacoemulsification time. ACD can be used as an essential parameter preoperatively to determine the choice of surgical technique between MSICS and phacoemulsification.

Evaluation and correlation of corneal endothelium parameters with the severity of primary glaucoma

Purpose

To evaluate and correlate corneal endothelium parameters with the severity of primary glaucoma.

Methods

This prospective case-control study was conducted on 150 eyes of 80 newly diagnosed primary open-angle glaucoma (POAG), chronic primary angle-closure glaucoma (cPACG), and normal-tension glaucoma (NTG) patients in a tertiary care center. Endothelial parameters including endothelial cell count (ECC), percentage of hexagonal cells, and coefficient of variation of cell size were analyzed. Glaucoma cases were further sub-grouped into early, moderate, and severe glaucoma and compared for endothelial parameters. Chi-square, Fischer's exact test, independent sample t-test, and analysis of variance were performed using IBM^® SPSS^® Statistics version 28.

Results

The ECC was markedly reduced in cases (2281 cells/mm²) versus controls (2611 cells/mm²) (P < 0.001). The POAG (2251 cells/mm²) and cPACG (2287 cells/mm²) eyes had significantly a lower ECC compared to healthy controls (P < 0.001), whereas NTG eyes had a lower mean ECC (2538 cells/mm²), but it was not statistically significant (P > 0.05) when compared with controls. The ECC decreased with an increase in severity as patients with early glaucoma had an ECC of 2284 cells/mm², moderate 2261 cells/mm², and severe 2086 cells/mm², and the difference was statistically significant.

Conclusion

A significant decrease in corneal ECC was observed in POAG and cPACG patients when compared with healthy controls of the same age group. Mechanical damage following an elevated intra-ocular pressure for a longer duration may be attributed to morphological and consequent functional damage to endothelial cells.

Successful Phakic Intraocular Lens Implantation with the Usage of Topical Ascorbic Acid in Patient with Reduced Corneal Endothelial Cell Density

We aimed to describe the use of topical ascorbic acid (AA) in a patient with reduced endothelial cells density (ECD) who was scheduled for phakic intraocular lens (pIOL) implantation. A 28-year-old woman presenting with dry eye and reduced ECD would like to have her high myopia (spherical equivalence >−15.0 D) corrected. The procedure of laser refractive surgery or even pIOL was not indicated for the reduced ECD of 1865/mm2 in the right eye and 2188/mm2 in the left eye, as well as level 3 dry eye. Fortunately, the ECD increased to 3144/mm2 in the right eye and 2538/mm2 in the left eye after topical AA was prescribed for one year preoperatively and one month postoperatively, with concomitant improvement of dry eye to level 1. Finally, bilateral pIOL implantation was performed smoothly and no sign of corneal decompensation was found postoperatively. Three months postoperatively, the ECD showed a satisfactory level of 2983/mm2 in the right eye and 3003/mm2 in the left eye. In conclusion, topical AA instillation might increase and maintain the density of central human corneal endothelial cells (HCECs) even after pIOL implantation.

Specular Microscopy of Human Corneas Stored in an Active Storage Machine

Purpose: Unlike corneas stored in cold storage (CS) which remain transparent and thin, corneas stored in organoculture (OC) cannot be assessed by specular microscopy (SM), because edema and posterior folds occur during storage and prevent from specular reflection. We previously developed an active storage machine (ASM) which restores the intraocular pressure while renewing the storage medium, thus preventing major stromal edema. Its transparent windows allow multimodal corneal imaging in a closed system. Aim: to present SM of corneas stored in this ASM. Methods: Ancillary study of two preclinical studies on corneas stored for one and three months in the ASM. A prototype non-contact SM was developed (CMOS camera, ×10 objective, collimated LED source, micrometric stage). Five non-overlapping fields (935 × 748 μm) were acquired in exactly the same areas at regular intervals. Image quality was graded according to defined categories (American Cornea Donor Study). The endothelial cell density (ECD) was measured with a center method. Finally, _SMECD was also compared to Hoechst-stained cell nuclei count (_HoechstECD). Results: The 62 corneas remained thin during storage, allowing SM at all time points without corneal deconditioning. Image quality varied depending on donors and days of control but, overall, in the 1100 images, we observed 55% of excellent and 30% of good quality images. _SMECD did not differ from _HoechstECD (p = 0.084). Conclusions: The ASM combines the advantages of CS (closed system) and OC (long-term storage). Specular microscopy is possible at any time in the ASM with a large field of view, making endothelial controls easy and safe.

A Nationwide Multicenter Study on 1-Year Outcomes of Posterior Chamber Phakic Intraocular Lens Implantation for Low Myopia

Purpose

To assess the nationwide multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients with low myopia.

Methods

This multicenter study comprised 172 eyes of 111 consecutive patients undergoing hole ICL implantation to correct low myopia and myopic astigmatism [manifest spherical equivalent (MSE);-3 diopters (D) or less] at seven nationwide major surgical facilities. We retrospectively determined safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, 6, and 12 months postoperatively, and at the final visit.

Results

The mean follow-up period was 1.4 ± 1.0 years. Uncorrected and corrected visual acuities at 1 year postoperatively were -0.17 ± 0.12 and -0.24 ± 0.07 logarithm of the minimal angle of resolution (logMAR), respectively. At 1 year postoperatively, 91% and 100% of eyes were within 0.5 and 1.0 D of the target correction, respectively. No significant manifest refraction changes of -0.07 ± 0.26 D occurred from 1 week to 1 year. No vision-threatening complications occurred at any time in this series.

Conclusions

According to our experience, the EVO-ICL performed well without significant complications throughout the 1-year observation period, even for the correction of low myopia. It is suggested that current ICL implantation is one of the viable surgical options for correcting low myopia.

Qualitative and Quantitative Evaluation of Donor Corneal Tissue by Slit Lamp and Specular Microscopy

Background In India, donor eye collection and promotion of eye banking are insufficient to meet the needs. By adequately evaluating donor corneas, eye banks can maximize the number of viable corneas for transplantation. This study evaluated donor corneal tissue based on age, lens status, and cause of death by their morphology and endothelial cell count via slit lamp and specular microscopy. Methods We conducted a prospective observational study of all eye bank donor corneas indicated for eye donation at a tertiary hospital and research center in Western Maharashtra between September 2019 to December 2021. We evaluated the corneoscleral discs by slit-lamp microscopy specular microscopy. We analyzed donor corneas quantitatively and qualitatively and graded them accordingly. We also collected blood samples for serological testing and the donor's behavioral and family medical histories. Results We collected 94 eyes from 47 donors; the mean age of the donor population was 48.2 years, and most donors were aged 41 to 80 years. Thirty-one donors (65.96%) were male, and 16 were female (34.04%. For preservation, we used Cornisol (Aurolab, Madurai, India) in 36 cases (77%) and McCarey-Kaufman medium in 11 cases (23%). We found a mean endothelial cell density (ECD) of 2214.40/mm2, with hexagonality of 53.05%, and a coefficient of variation of 38.01. Further, we observed that ECD and hexagonality of cells in phakic donors were significantly greater than that of pseudophakic (PP) donors. Moreover, ECD and hexagonality significantly decreased in donors with the chronic disease compared to those who had a sudden, unexpected death. Conclusion Corneal grafts from younger donors, phakic donors, and donors who experienced an acute cause of death were qualitatively and quantitatively significantly better than those of older donors, PP donors, and donors who experienced sudden, unexpected death. Therefore, eye bank specular examination can improve tissue utilization and transplantation success. Therefore, we strongly recommend that eye bank personnel evaluate their donor tissue with a specular microscope to enhance the quality of eye care.

Live surgery outcomes in cataract surgery

PURPOSE

To evaluate and compare the outcomes of live surgery (LS) and no-live surgery (NLS) on cataract surgery with implantation of different types of intraocular lenses (IOLs).

METHODS

Retrospective, contralateral eye, case series of patients that underwent cataract surgery in live or non-live view during two consecutive editions of national meetings. Both eyes of the same patients were implanted with the same IOL, one in LS and the other in NLS.

RESULTS

108 eyes of 54 patients, aged between 50 and 82 (72 ± 8.2) and implanted with different types of IOLs, were reviewed. Both eyes in each patient were well matched at baseline in terms of intraocular biometric characteristics, corneal curvature and endothelial cell density (ECD) (p > 0.05). There are no statistically significant differences between the biometric and topographic parameters, aberrometric data and the loss of ECD in the post-operative outcomes (p > 0.05). However, comparing the different types of IOLs, there is a significant loss of ECD in eyes implanted with a toric IOL during LS (p = 0.0014 and p = 0.04, in 2017 and 2018 edition respectively).

CONCLUSIONS

In this series of live cataract surgery, eyes operated in LS or NLS have comparable outcomes, underlying the importance and the benefits of live view in terms of medical education and the low-risk of complications. Nevertheless, we have found a significant increase in ECD loss in patients implanted with toric IOLs during LS.

Corneal endothelial cell density loss following glaucoma surgery alone or in combination with cataract surgery: A systematic review and meta-analysis

TOPIC

Corneal endothelial cell density (ECD) loss following glaucoma surgery with or without cataract surgery.

CLINICAL RELEVANCE

Corneal ECD loss may occur due to intraoperative surgical trauma in glaucoma surgery or postoperatively with chronic endothelial cell trauma or irritation.

METHODS

Trabeculectomy, glaucoma filtration surgery or microinvasive glaucoma surgery in participants with ocular hypertension, primary and secondary open angle glaucoma, normal tension glaucoma and angle-closure glaucoma were included. Pediatric populations and participants with pre-existing corneal disease were excluded. Laser treatments and peripheral iridotomy were excluded. Electronic databases searched in December 2021 included MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov and The International Prospective Register of Systematic Reviews (PROSPERO), FDA PMA and FDA 510(k).

RESULTS

39 studies were included in quantitative synthesis. 12 months following suprachoroidal MIGS mean ECD loss was 282 cells/mm² (95% Confidence Interval (CI) 220 to 345; p <0.00001; Chi² = 0.06; I² = 0%; 2 studies; very low certainty). Mean ECD loss after Schlemm's canal implantable devices was 338 cells/mm² (95% CI 185 to 491; p<0.0001; Chi² = 0.08; I² = 0%; 2 studies; low certainty) at 12 months. When compared to phacoemulsification alone, Schlemm's canal implants combined with phacoemulsification showed statistically significant mean ECD reduction at 24 months; mean difference of ECD was -19% (95% CI -37% to -2%; p=0.03; Chi² = 3.04; I² = 34%; 3 studies; low certainty). Mean ECD loss was 64 cells/mm² (95% CI 21 to 107; p=0.004; Chi² = 4.55; I² = 0%; 6 studies; low certainty) following Schlemm's canal procedures (without implantable devices) at 12 months. At 12 months the mean ECD loss after trabeculectomy was 33 cells/mm² (95% CI -38 to 105, p=0.36, Chi² = 1.17; I² = 0%; moderate certainty). At 12 months mean ECD loss was 121 cells/mm² (95% CI 53 to 189; p=0.0005; Chi² = 3.00; I² = 0%; 5 studies; low certainty) after Express implantation. When compared to control fellow eye, aqueous shunt surgery reduced ECD by 5.75% (95% CI -0.93 to 12.43; p=0.09 Chi² = 1.32; I² = 0%; low certainty) and 8.11% ECD loss (95%CI 0.06 to 16.16 p=0.05; Chi²= 1.93; I²=48%) at 12 and 24 months, respectively.

CONCLUSIONS

Overall there is low certainty evidence to suggest that glaucoma surgery involving long-term implants has a greater extent of ECD loss than glaucoma filtration surgeries without the use of implants. The results of this review support long-term follow-up (beyond 36 months) to assess ECD loss and corneal decompensation following implantation of glaucoma drainage implants.

Effect of mitomycin-C on corneal endothelial cell parameters after refractive surface ablation procedures

Background

The effect of mitomycin-C (MMC) on the reduction of endothelial cell count in the cornea remains controversial. We aimed to evaluate the effect of MMC on corneal endothelial cell parameters after refractive surface ablation procedures, including photorefractive keratectomy (PRK) and laser epithelial keratomileusis (LASEK).

Methods

In this interventional, comparative, follow-up study, 342 eyes of 171 patients were followed up for 6 months. Patients undergoing PRK or LASEK were included and were divided into two groups: group one (188 eyes of 94 patients) with an ablation depth of ≥ 65 µm and who received intraoperative 0.02% MMC for 30 s, and group two (154 eyes of 77 patients) with an ablation depth of < 65 µm and who received balanced salt solution for 30 s. Changes in endothelial cell density (ECD), central corneal thickness (CCT), coefficient of variation (CV), and hexagonality values were compared between the groups at 3 and 6 months after surgery.

Results

The mean (standard deviaiton [SD]) age of the patients was 28.11 (6.56) years. The mean (SD) ECD did not change significantly in either group between the baseline and at 3 and 6 months postoperatively. The baseline mean ECD was significantly higher in group one than that in group two (P < 0.001) and remained so at 3 (P = 0.002) and 6 months (P = 0.022) postoperatively. The baseline hexagonality value was lower in group one (P = 0.173), with a gradual decrease during the postoperative follow-up as compared with that in group two (P = 0.016 and 0.001 at 3 and 6 months postoperatively, respectively). Group one had a significantly lower CCT at 3 and 6 months postoperatively (both P < 0.001) and a higher mean CV (3 months: P = 0.028; 6 months: P = 0.328).

Conclusions

A single intraoperative application of MMC for 30 s as prophylaxis for corneal haze development during refractive surface ablation procedures had no significant effect on ECD up to 6 months postoperatively. Future studies with a contralateral-eye design (to neutralize factors specific to the individual patient), a larger sample size, and longer follow-up are necessary to confirm or disprove our observations.

Corneal Endothelial Changes Following Early Capsulotomy Using Neodymium:Yttrium-Aluminum-Garnet Laser

We aimed to survey whether the timing of neodymium:yttrium–aluminum–garnet (Nd:YAG) laser capsulotomy would alter the corneal endothelial morphology and density. A retrospective cohort study was conducted, and 48 patients with unilateral posterior capsular opacity (PCO) and Nd:YAG laser capsulotomy performance were enrolled. The participants were divided into the early Nd:YAG group (timing ≤ 12 months, n = 20) and late Nd:YAG group (timing > 12 months, n= 28) depending on elapsed months between phacoemulsification and Nd:YAG laser capsulotomy. Endothelial cell density (ECD), coefficient of variant (CV), hexagonality (HEX), and central corneal thickness (CCT) between the two groups were collected. A generalized estimate equation was conducted to evaluate the corneal endothelial parameters between the two groups with an adjusted odds ratio (aOR) and 95% confidence interval (CI). The CDVA was improved after treatment in both groups (both p < 0.001). Chronically, ECD in the early group was significantly decreased one week after treatment (2221.50 ± 327.73/mm² vs. 2441.55 ± 321.80/mm², p < 0.001), which recovered to 2369.95 ± 76.37/mm² four weeks after the treatment but was still lower than the preoperative status (p < 0.001). In addition, the HEX percentage showed a significant reduction at four weeks after treatment (p = 0.028). The ECD in the early group was significantly lower than that in the late group (aOR: 0.167, 95% CI: 0.079–0.356, p = 0.003) in both week 1 (p < 0.001) and week 4 (p = 0.004) after laser treatment. In conclusion, the early application of Nd:YAG laser capsulotomy within one year after cataract surgery may be the reason for postoperative ECD decrement without known etiology.

Correlation between ocular biometric parameters and corneal endothelium in a sample of young Egyptian adults

Background

To evaluate the normative values of corneal endothelial cell parameters within a group of healthy young Egyptian adults using specular microscopy and to examine any correlations between endothelial parameters and refractive or biometric parameters.

Methods

In this cross-sectional study, specular microscopy was used to study the right eyes of 150 healthy young volunteers and evaluated endothelial cell parameters, including cellular density, hexagonality (HEX), and coefficient of variation (CV) at 15 different points on the back corneal surface, which were later grouped into the central zone and either four quadrants or three annular zones. The same eyes underwent refractive and biometric assessments.

Results

Hundred fifty healthy adults were examined, and the age ranged from 20 to 30 years, with a median of 23 (interquartile range, 21‒27) years. The mean (standard deviation) of central cell density was 2902.7 (270.7) cells/mm2. The superior paracentral area had the lowest mean density (2895.8 cells/mm2), but the highest mean HEX (67.7%), while the inferior peripheral area had the highest mean density (3100.5 cells/ mm2) but the lowest mean HEX (64%). The difference in cell density among the three annular zones was not statistically significant (P = 0.365). However, HEX and CV in the central and paracentral zones differed statistically significantly from those of the peripheral zone (P < 0.001 and P = 0.014, respectively). Weak but non-significant correlations were detected between endothelial cell density and all measured refractive and biometric parameters.

Conclusions

The findings of this study provided useful normative biometric and specular data in a specific age group and a specific population, and could be useful in planning intraocular surgery in young Egyptian adults. However, future longitudinal studies with a larger sample could refine more endothelial cell parameter specifications over time.

Automated Image Segmentation of the Corneal Endothelium in Patients With Fuchs Dystrophy

Purpose

To perform segmentation of specular microscopy (SM) images of the corneal endothelium for comparing average perimeter length (APL) between Fuchs endothelial corneal dystrophy (FECD) patients and healthy subjects.

Methods

A retrospective review of clinical records of FECD patients and those with healthy endothelium was carried out to collect images of the endothelium. The images were segmented by modified U-Net, a deep learning architecture, followed by the Watershed algorithm to resolve merged cell borders (<5%). The segmented images were analyzed for endothelial cell density (ECDUW) and APL.

Results

The combination of the U-Net and Watershed algorithm, referred to as the UW approach, enabled a complete segmentation of the endothelium. In healthy, ECDUW was close to estimates by SM and manual segmentation (31 subjects; P > 0.1). However, in FECD, ECDUW was closer to estimates by manual segmentation but not by SM (27 patients; P < 0.001). ECDUW in FECD (2547 ± 499 cells/mm2; 60 patients) was smaller compared to that in the healthy (2713 ± 401 cells/mm2; 70 subjects) (P < 0.001). APL in the healthy was 66.87 ± 7.68 µm/cell (70 subjects), but it increased with %Guttae in FECD (56.60-195.30 µm/cell; 60 patients) (P < 0.0001).

Conclusions

The UW approach is precise for the segmentation of SM images from the healthy and FECD. Our analysis has revealed that APL increases with %Guttae.

Translational Relevance

The average perimeter length of the corneal endothelium, which represents the length of the paracellular pathway for fluid flux into the stroma, is increased in Fuchs dystrophy.

Endothelial cell loss rate after penetrating keratoplasty: optical versus therapeutic grafts

Background

This study aimed to compare the rate of endothelial cell loss (ECL) after penetrating keratoplasty (PKP) for optical versus therapeutic grafts at 3-, 6-, and 12-month postoperatively. Furthermore, the study aimed to investigate postoperative graft viability and the rate of graft rejection during the first year of follow-up for both indications.

Methods

This was a prospective, observational, comparative study that included patients who sought medical advice at the cornea outpatient clinic of Ain Shams University Hospitals, Cairo, Egypt. The study recruited 60 patients: group 1 included 30 transplanted corneas of 30 patients who underwent optical PKP for various indications, while group 2 included 30 transplanted corneas of 30 patients who underwent therapeutic PKP for unhealed, resistant infectious keratitis. Specular microscopy was performed for all patients at the 3-, 6-, and 12-month follow-up visits using Nidek CEM-530 specular microscopy. Postoperative clinical examinations were performed at the same follow-up visits to detect graft rejection.

Results

There were no statistically significant differences between the groups concerning the postoperative timing of graft clarity or the rate of ECL at 3- and 6-months postoperatively; however, the rate of ECL was significantly greater in group 2 than in group 1 at 12-months postoperatively (P = 0.03), although the difference was small from a clinical point of view. Moreover, there was no statistically significant difference between the groups in terms of the graft rejection rate.

Conclusions

Therapeutic PKP results were comparable to optical PKP with respect to graft viability, the rate of ECL, and the rate of graft rejection 1 year after grafting.

How to Predict the Suitability for Corneal Donorship?

Background: In Germany, more than one-third of donor corneas harvested are not suitable for transplantation. We evaluated the factors associated with the usability of donor corneas. Method: Data from 2032 consecutive donor corneas harvested at the Rhineland-Palatinate Eye Bank in Mainz, Germany, were retrospectively analyzed. Factors of interest were age, sex, lens status, cause of death, cardiopulmonary resuscitation (CPR), death-to-explantation-interval (DEI), and the influence of these factors on the proportion of discarded donor corneas. Factors associated with endothelial cell density (ECD) were analyzed in a linear regression mixed model. Results: Higher donor age, male gender, pseudophakic lens status, and longer DEI were associated with significantly reduced ECD. With respect to DEI, the estimated cell loss was 7 ± 2 cells/mm²/hour (p < 0.001). Age was associated with a lower ECD of 6 ± 2 cells/mm² per year (p = 0.001). Female ECD was 189 ± 44 cells/mm² higher than male ECD (p < 0.001). Pseudophakic eyes had 378 ± 42 cells/mm² less compared with phakic eyes (p < 0.001). Cause of death did not affect the ECD. Of note, 55% and 38% of corneas harvested on the second and third postmortem day, respectively, and 45% of corneas from donors older than 80 years were still suitable for transplantation. Conclusions: In the context of a growing need for donor corneas, we do not recommend limiting donor age and collection time to 24 h or excluding oncology donors, as is the practice in many countries. Therefore, we propose a mathematical model for better donor preselection.

Overall clinical outcomes of Descemet membrane endothelial keratoplasty in 600 consecutive eyes: A large retrospective case series

Purpose:

To analyze the overall clinical outcomes of Descemet membrane endothelial keratoplasty (DMEK) in 600 consecutive cases.

Methods:

Retrospective, consecutive interventional case series operated by a single surgeon. Six hundred consecutive eyes of 524 patients with endothelial dysfunctions of different etiologies scheduled for DMEK were included in this study. All donor tissues were prepared by the operating surgeon during the procedure, using McCarey Kaufman medium or Cornisol-preserved cornea with endothelial cell density (ECD) of ≥2500 cells/mm². Indications, postoperative best spectacle-corrected visual acuity (BSCVA), ECD, endothelial cell loss (ECL), and complications were analyzed postoperatively between 3 months and 2 years.

Results:

The commonest indication was post-cataract corneal edema/bullous keratopathy in 262 (43.7%) eyes followed by Fuchs′ endothelial corneal dystrophy 218 (36.3%). Vision affected comorbidities were present in 91 (15.2%) eyes. In phakic eyes with cataract (222; 37%), DMEK was combined with cataract surgery (Triple-DMEK). BSCVA of ≥20/25 was achieved in 41.0%, 46.4%, 49.2%, and 48.7% of eyes at 3, 6, 12, and 24 months, respectively and stabilized at 6 months (P = 0.54). Mean ECD decreased from 2884 ± 178 cells/mm² (n = 600) before surgery to 2223 ± 321 (n = 597), 2099 ± 354 (n = 524), 1918 ± 373 (n = 374), and 1772 ± 439 cells/mm² (n = 158) at 3, 6, 12, and 24 months respectively. The corresponding mean ECL was 22.9 ± 11.4%, 27.2 ± 12.4%, 33.5 ± 13.0%, and 38.6 ± 14.3%, respectively (P < 0.05 for all-time points). The commonest complication was DM detachment in 59 (9.8%) eyes of which 23 (3.8%) eyes required rebubbling. Three (0.5%) eyes had primary graft failure. Endothelial rejection occurred in 7 (1.2%) eyes until the last follow-up.

Conclusion:

DMEK is a safe and effective procedure in different types of endothelial diseases with encouraging surgical and clinical outcomes. Complications are less and ECL percentage up to 2 years is acceptable.

Do topical antiglaucoma drugs affect the cornea?

To investigate effects of beta blocker (BB; timolol or betaxolol), latanoprost, and latanoprost-timolol combination (LTC) drugs on corneal endothelial cell density (ECD) and central corneal thickness (CCT) in primary open-angle glaucoma (POAG) patients. Sixty-one patients in BB group, 64 patients in latanoprost group, 59 patients in LTC group, and 58 healthy cases in control group were included. Intraocular pressures (IOP), ECDs, and CCTs of groups were recorded at initial (pre-treatment) period, first and third years after treatment, and comparisons were done. In groups, changes of ECDs according to time were not significant (p > 0.05). In BB and control groups, changes of CCTs according to time were not significant (p > 0.05). In latanoprost and LTC groups, CCTs in both first and third years were significantly thinner than initial CCTs (p = 0.039 for latanoprost, p = 0.041 for LTC at first year; p = 0.018 for latanoprost, p = 0.032 for LTC at third year). In latanoprost and LTC groups, CCTs of patients using drugs for 1 year were similar to those of patients using drugs for 3 years (p > 0.05). In our study, uses of BB, latanoprost or LTC did not affect ECD. BB drugs had no effect on CCT. Although latanoprost and LTC appeared to reduce CCT at 3-year follow-up from the statistical point of view, this 8-10 μm difference in CCT was not clinically significant.

Outcomes of rebubbling for graft detachment after Descemet's stripping endothelial keratoplasty or Descemet's stripping automated endothelial keratoplasty

Purpose

To study the outcomes of rebubbling for graft detachment after Descemet's stripping endothelial keratoplasty (DSEK) or Descemet's stripping automated endothelial keratoplasty (DSAEK).

Methods

From 2260 eyes that underwent DSEK or DSAEK from July 2008 to June 2015, 80 eyes of 80 patients developed graft detachment and were retrospectively reviewed. Host-related, surgery-related and donor-related factors that have a bearing on graft adhesion were looked at retrospectively, and eventual outcomes after rebubbling procedure were studied.

Results

Successful attachment was observed in 77 (96.25%) eyes and clear grafts were achieved in 55 (68.75%) eyes, while 25 (31.25%) eyes had graft failure. The uncorrected and best-corrected distance visual acuities significantly improved from 1 month to 3 months post-operatively and remained stable till 12 months of follow-up. Three lenticules that failed to attach with the first rebubbling procedure underwent a second rebubbling, two underwent a repeat DSEK with good outcomes and four underwent penetrating keratoplasty. On evaluating possible risk factors for graft failure, lower donor endothelial cell density was found to be a significant factor (P = 0.03). The median graft survival following rebubbling was 30 months.

Conclusion

Rebubbling procedure in detached grafts after DSEK or DSAEK can reattach the lenticule in 96% of eyes in immediate post-operative period and the majority of the grafts remained clear on long-term follow-up with a median graft survival period of 2.5 years.

Effect of Angle Opening Parameters on Corneal Endothelial Cell Density and Intraocular Pressure after Posterior Chamber Phakic Intraocular Lens Implantation

This study aimed to investigate the time courses of angle opening parameters and the relationships of these with the corneal endothelial cell density (ECD) and the intraocular pressure (IOP) after posterior chamber phakic intraocular lens (Visian ICL^TM, STAAR Surgical) implantation. We evaluated 116 eyes of 59 consecutive patients (mean age ± standard deviation, 34.0 ± 8.8 years) who underwent V5 implantable collamer lens (ICL) implantation. Preoperatively and 1 day, 1 week, and 1, 3, and 18 months postoperatively, we quantitatively measured the angle opening distance at 500 µm (AOD500), the trabecular-iris space area (TISA500), and the trabecular iris angle (TIA500), using anterior segment optical coherence tomography (CASIA 2, Tomey), and assessed the relationships of these measurements with ECD and IOP in ICL-implanted eyes. All angle parameters (AOD500, TISA500, and TIA500) significantly decreased 1 day postoperatively but remained stable thereafter. At 18 months postoperatively, we found no significant correlations of the angle parameters with ECD (Pearson correlation coefficient r = −0.108, p = 0.249 for AOD500; r = −0.162, p = 0.083 for TISA500; r = −0.022, p = 0.815 for TIA500) or between the angle parameters and IOP (r = −0.106, p = 0.256 for AOD500; r = −0.021, p = 0.826 for TISA500; r = −0.018, p = 0.850 for TIA500). The angle opening metrics significantly decreased immediately after ICL implantation but remained stable thereafter. Narrowing of the angle did not significantly affect ECD or IOP in ICL-implanted eyes during the 18-month postoperative period.

Safety and visual outcomes following Iris-claw phakic intraocular lens bilensectomy

PURPOSE

To evaluate the visual outcomes, safety, efficacy, and causes of bilensectomy for iris fixated phakic intraocular lenses (pIOLs).

METHODS

This was a two center consecutive retrospective study that included 43 eyes that underwent iris-claw pIOL bilensectomy. Patients with follow up less than 4 months were excluded from the study. Uncorrected, corrected visual acuity (UCVA, CDVA), refractive outcomes, efficacy, safety (number of eyes in which the postoperative CDVA was worse than the preoperative CDVA), endothelial cell density (ECD), causes of bilensectomy, the time between the implantation of the pIOL and bilensectomy, intra and postoperative complications were analyzed.

RESULTS

There was a statistically significant improvement in UCVA and CDVA after surgery (p = 0.001). The efficacy index was 0.7, four eyes had a postoperative CDVA worse than the preoperative CDVA. The mean spherical equivalent 1 year after bilensectomy was -0.78 ± 1.70 D. There was a statistically significant endothelial cell loss after iris claw lens bilensectomy (p = .003). Cataract development and endothelial cell loss were the only reasons for bilensectomy. The mean time between pIOL implantation and bilensectomy was 12.2 ± 5.5 years. One patient had corneal edema 8 months after surgery and one had a retinal detachment 11 months after surgery.

CONCLUSION

Bilensectomy was successful in improving UCVA and CDVA with an acceptable refractive outcome. Significant loss of ECD was found after surgery. The results recommend a larger ACD as selection criteria when choosing to implant an Artisan lens, and a close postoperative monitoring of the endothelial cell count.

Corneal endothelial cell loss following cataract surgery in patients with pseudoexfoliation syndrome: a 2-year prospective comparative study

PURPOSE

To compare the corneal endothelial cell density (ECD) before and after cataract surgery in patients with and without pseudoexfoliation syndrome (PEX).

METHODS

In this prospective study, we compared the ECD in 62 PEX patients with 62 patients without PEX (controls). The mean age was 78.3 ± 6.2 years and 77.2 ± 5.9 years, respectively. Patients were examined before and at 6 months, 1 year and 2 years after cataract surgery. The corneal endothelium was examined with confocal microscopy, and the ECD was counted both automatically and semi-manually. Nine patients in the PEX group (15%) and 11 patients in the control group (18%) were lost to follow-up in the 2-year period. Within the PEX and the control groups, we also compared the ECD between patients with and without glaucoma.

RESULTS

Before surgery, the ECD (semi-manual counting) was 2258 ± 342 cells/mm² in the PEX group and 2322 ± 321 cells/mm² in the control group (p = 0.29). There were no significant differences in postoperative ECD between these groups at any visit. After 2 years, the ECD had changed by -679 ± 337 cells/mm² and -704 ± 484 cells/mm² , respectively (p = 0.78). The preoperative ECD was lower in eyes with glaucoma compared to eyes without glaucoma, both within the PEX group (p = 0.05) and the control group (p = 0.03). After surgery, there were no differences between eyes with or without glaucoma.

CONCLUSION

The ECD was not significantly different in PEX eyes compared with control eyes, neither before nor after cataract surgery. However, there seemed to be a lower ECD in eyes with glaucoma before surgery.

Combined specular microscopy and Scheimpflug imaging to improve detection of an upcoming allograft rejection after DMEK

PURPOSE

To assess whether combined analysis of specular microscopy and Scheimpflug imaging improves detection of an upcoming allograft rejection following Descemet membrane endothelial keratoplasty (DMEK).

METHODS

Retrospective analysis of 22 eyes that had developed a clinical proven allograft rejection 28 (±22) months (range: 4-84 months) after DMEK. Specular microscopy and Scheimpflug images routinely made after DMEK were retrospectively analysed for changes in endothelial cell morphology (e.g. nuclear activation), cell density (>10%) and pachymetry (>7%), and/or the presence of subclinical keratic precipitates. The same parameters were evaluated for 22 control eyes matched for age, gender and surgery indication.

RESULTS

A total of 20/22 eyes (91%) showed detectable changes 0.25-75 months before allograft rejection became clinically manifest: 13/22 (59%) showed both specular microscopy and Scheimpflug imaging changes; 5/22 (23%) only had changes on Scheimpflug imaging; and 2/22 (9%) only had specular microscopy changes. In 18/22 (82%) and 14/22 (64%) eyes, subclinical keratic precipitates and endothelial cell morphology changes could be detected, respectively. A total of 11/22 (50%) eyes concurrently showed a >10% drop in endothelial cell density and 4/22 (18%) a >7% pachymetry increase. Of the control eyes, 7/22 (32%) showed changes with specular microscopy but not with Scheimpflug imaging.

CONCLUSIONS

Combined analysis of specular microscopy and Scheimpflug imaging may allow recognizing an upcoming allograft rejection in over 90% of eyes and up to 6 years before rejection becomes clinically manifest. Early recognition of eyes at risk may allow for targeted intensified steroid treatment to prevent endothelial cell damage associated with rejection.

Effect of glaucoma drainage implant surgery on corneal topography: a prospective study

PURPOSE

To study the effect of glaucoma drainage implant (GDI) surgery on corneal topography during the first postoperative year.

METHODS

Twenty-one adult glaucoma patients were implanted with a Molteno3 or a Baerveldt 250 GDI. Corneal topography measurements were taken preoperatively and at 6 and 12 months after surgery. Untreated opposite eyes served as controls.

RESULTS

In the surgical group, the mean ± SD simulated average keratometry values were 44.36 ± 1.69 D, 44.08 ± 1.29 D (p = 0.266) and 44.15 ± 1.32 D (p = 0.554) before and 6 and 12 months after surgery, respectively. The corresponding simulated keratometry astigmatism values were 1.11 ± 1.11 D, 1.20 ± 1.01 D (p = 0.687) and 1.16 ± 0.71 D (p = 0.177). Posterior astigmatism and posterior average keratometry remained unchanged after GDI surgery as well. The mean ± SD central corneal thickness (CCT) was 530 ± 46 μm, 535 ± 56 μm (p = 0.049) and 536 ± 45 μm (p = 0.080) at 0, 6 and 12 months, respectively. A trend towards increased corneal thickness (CT) in response to GDI surgery was also seen in both the average peripheral and the tube-quadrant peripheral CT values. At 12 months postoperatively, the mean endothelial cell density (ECD) had decreased by 8% centrally and by 9% peripherally. Corneal topography parameters, CT and ECD did not significantly change in the control group during follow-up.

CONCLUSION

Glaucoma drainage implant (GDI) surgery did not significantly alter corneal keratometry parameters and thus seems to be an astigmatically neutral procedure. However a slight, although seemingly transient, increase in CCT was observed after GDI implantation.

Improved Interchangeability with Different Corneal Specular Microscopes for Quantitative Endothelial Cell Analysis

Introduction

During our clinical practice and research, we encountered an interchangeability problem when using the SP-2000P and SP-3000P TopCon corneal specular microscopes (CSMs) (TopCon Medical Systems, Tokyo, Japan) regarding the endothelial cell count (ECC). We describe a method to improve interchangeability between these CSMs.

Methods

Five consecutive good-quality endothelial cell photographs were obtained in 22 eyes of 11 subjects. An ECC comparison between the two CSMs was performed after (I) gauging and calibration by the manufacturer, (II) adjustment of the magnification, (III) correction after external horizontal and vertical calibration.

Results

There was a statistically significant difference between the ECC of the SP-2000P and SP-3000P at the start. The SP-2000P counted an average of 500 cells/mm² more than the SP-3000P (p=0.00). After correction for magnification and determining a correction factor based on external calibration, the difference between the ECC of the SP-2000P and the SP-3000P was then found to be 0.4 cells/mm² and was not statistically significant (p=0.98).

Discussion

We propose a method for improving interchangeability, which involves checking magnification settings, re-checking magnification calibration with external calibration devices, and then calculating correction factors. This method can be applied to various specular or confocal microscopes and their associated endothelial cell analysis software packages to be able to keep performing precise endothelial cell counts and to enable comparison of ECCs when a CSM needs to be replaced or when results from different microscopes need to be compared.

Corneal thickness and endothelial cell density in children with type 1 diabetes mellitus

BACKGROUND:

The aim of this study was to detect the effect of diabetes on the corneal endothelium in patients of Type 1 diabetes in the pediatric age group and to compare them with age-matched controls. Further, it was proposed to establish any correlation between these changes and risk factors of diabetes, viz., age, duration of diabetes, and hemoglobin A1c (HbA1c) values.

MATERIALS AND METHODS:

This was a prospective cross-sectional study. Fifty children with Type 1 diabetes, between the ages of 7 and 17 years (average, 12.16 ± 2.63 years), and fifty healthy age-matched controls (average 12.28- ±3.00 years) were examined. The central corneal thickness (CCT) and endothelial cell density (CD) were assessed by the Topcon SP-1P specular microscope. The duration of diabetes (average, 3.91 ± 1.65 years) and the HbA1c values (average, 10.92 ± 2.28) were also noted.

RESULTS:

The average CCT in the diabetics was 525.16 ± 33.14 μ and in the controls 513.44 ± 29.46 μ. This was significantly higher (P = 0.015). The average endothelial CD in the diabetics was 3039.64 ± 292.84 cells/mm² and in the nondiabetics 3360.41 ± 268.04 cells/mm². This was significantly lower (P < 0.001). A significant correlation was found between the endothelial CD and age of the diabetic patients (P = 0.008). However, there was no significant correlation between the endothelial CD and the CCT with either duration of diabetes or HbA1c.

CONCLUSIONS:

A significant decrease in the endothelial CD and increase in the CCT occurs in children and adolescents with Type 1 diabetes. With the age of the diabetic patients, the endothelial CD significantly reduces. However, duration of diabetes and HbA1c do not affect these values.

Significant differences between specular microscopy and corneal bank endothelial cell counts - a pilot study

BACKGROUND

It was shown recently that endothelial cell count performed by cornea banks overestimates the real number of endothelial cells. The aim of this study was to investigate the internal quality of preclinical ECD in human donor corneas using two widely used methods for endothelial cell counting, transmitted light microscopy used in organ culture tissue bank and clinically used specular microscopy.

METHODS

Twenty human donor corneas that could not be transplanted were included in this analysis. Differences in evaluating endothelial cell density (ECD) and hexagonal endothelial cell ratio (HEX) between clinical specular microscopy (CSM) and corneal bank transmitted light microscope (CBLM) were evaluated as well as differences between automated and manual cell counts.

RESULTS

Automated CBLM showed a higher ECD of 31.85% compared to automated CSM, while manual CBLM counting is 10.51% higher compared to manual CSM (p < 0.01). Further, higher average ECD values result in a higher difference between CSM and CBLM measurements. The manual CBLM ECDs were significantly higher compared to automated derived ECD from CSM (p < 0.01). However, no systematic bias can be detected when comparing the differences of the measurements with the average ECD measurements of both methods.

CONCLUSION

This preclinical pilot study confirmed a significant higher ECD using transmitted light microscopy in organ culture compared to clinical specular microscopy. This indicates that the early rapid decrease of EC universally observed after surgery might be partly artefactual.

Phakic Intraocular Lens Implantation After Deep Anterior Lamellar Keratoplasty: Retrospective Case Series Analysis With Long-Term Follow-Up

Purpose

To report outcomes of phakic intraocular lens (IOL) implantation after deep anterior lamellar keratoplasty (DALK) to correct high ametropia.

Setting

Centro Hospitalar Universitário do Porto, Portugal.

Methods

Retrospective case series with 11 eyes submitted to phakic IOL implantation after DALK. Main outcomes measured were uncorrected and corrected distance visual acuity (UDVA and CDVA), refractive error components, tomographic parameters and endothelial cell density (ECD). The minimum follow-up was 3 years for all cases.

Results

Mean ECD loss was 8.7±6.7% at 1 year, 13.1±8.6% at 3 years (n=11; p=0.016, p=0.007, respectively) and 14.0±20.4% at 5 years (n=5, p=0.212). Mean logMAR UDVA increased from 1.27±0.90logMAR preoperatively to 0.16±0.15logMAR postoperatively (p≤0.001) and no statistically significant differences were registered during follow-up. All patients gained at least 5 lines of UDVA. 54.5% of the eyes gained 1 line in CDVA postoperative and only one eye lost one CDVA line through follow-up. Efficacy and safety indexes at 1 and 3 years were 1.01–0.97 and 1.24–1.21, respectively. Mean spherical equivalent was reduced from −7.84±4.63 D preoperatively to −1.05±1.07 D postoperatively (p=0.001). Mean percentage of reduction in refractive cylinder and spherical error was 83.8±15.8% and 73.1±31.5%, respectively, p≤0.001 for both. In one eye there was a significantly gradual ECD loss over 5 years follow-up and the patient will be submitted to IOL explant.

Conclusion

Phakic IOLs were effective for correction high ametropia after DALK, showing high efficacy and safety indexes with stability over time. However, it was registered a continuing endothelial cell loss postoperatively, which assumed to be higher than those reported in eyes without DALK.

Comparison of automated vs manual analysis of corneal endothelial cell density and morphology in normal and corneal endothelial dystrophy-affected dogs

OBJECTIVE

To determine the efficacy of automated imaging software of the Nidek ConfoScan 4 confocal biomicroscope at analyzing canine corneal endothelial cell density and morphology in health and disease, by comparing to a manual analysis method.

ANIMAL STUDIED

Nineteen eyes of 10 dogs were evaluated and include three Beagles, three Jack Russell Terriers, and four miscellaneous breeds. Twelve clinically normal and seven eyes affected with corneal endothelial dystrophy (CED) were scanned and analyzed.

PROCEDURES

Endothelial cell density (ECD), mean and standard deviation (SD) of cell area, percent polymegathism, mean and SD of the number of cell sides, and percent pleomorphism were calculated using automated and manual methods for each scan.

RESULTS

The automated analysis showed significantly greater ECD in comparison with the manual frame method due to misidentification of cell domains in CED-affected dogs. No significant differences in ECD were observed between normal and CED-affected dogs in automated analysis, while CED-affected dogs showed significantly lower ECD in manual frame method and planimetry. Using both automated and manual methods, CED-affected dogs showed greater variability of cell area or the number of cell sides than normal dogs.

CONCLUSION

The automated imaging software is unable to accurately identify cell borders in CED-affected dogs resulting in inaccurate estimates of ECD. Thus, manual analysis is recommended for use in clinical trials assessing adverse events associated with novel medical treatments and/or surgical procedures.

Comparison of changes in corneal endothelial cell density and central corneal thickness between conventional and femtosecond laser-assisted cataract surgery: a randomised, controlled clinical trial

BACKGROUND/AIM

To identify changes in endothelial cell density (ECD) and central corneal thickness (CCT) in eyes undergoing femtosecond laser-assisted cataract surgery (FLACS) compared with conventional phacoemulsification surgery (CPS).

METHODS

This is an intraindividual randomised, controlled clinical trial. One eye was randomised to receive FLACS, while the contralateral eye of the same patient received CPS. The femtosecond laser pretreatment included creating main and side-port corneal incisions, capsulotomy and lens fragmentation. Non-contact endothelial cell microscopy and pachymetry were performed preoperatively and at postoperative day 1, week 1, month 1 and month 3.

RESULTS

A total of 134 paired eyes from 67 patients were included in the analysis. ECD was not significantly different between the two groups at either postoperative month 1 (2370±580 cells/mm² and 2467±564 cells/mm² in FLACS and CPS groups, respectively; p=0.18) or at postoperative month 3 (2374±527 cells/mm² and 2433±526 cells/mm² in FLACS and CPS groups, respectively; p=0.19). No significant difference was observed in the mean CCT values between the two groups over the follow-up period (p>0.05).

CONCLUSION

Postoperative corneal ECD and CCT were comparable between FLACS and CPS during the 3 months' follow-up period.

Comparison of endothelial/Descemet's membrane complex thickness with endothelial cell density for the diagnosis of corneal transplant rejection

Purpose:

This study compared the effectiveness of endothelial/Descemet’s membrane complex thickness obtained using high-definition anterior segment optical coherence tomography with endothelial cell density obtained using confocal microscopy as diagnostic tools in predicting corneal transplant rejection.

Methods:

This observational, prospective, cross-sectional study evaluated penetrating keratoplasty grafts. Slit lamp examination organized the grafts into healthy or rejecting grafts. Grafts were scanned using both high-definition anterior segment optical coherence tomography and confocal microscopy. Central corneal thickness, endothelial/Descemet’s membrane complex thickness, endothelial cell density, and coefficient of variation were each compared with the clinical status. Descemet’s rejection index, defined by endothelial/Descemet’s membrane complex thickness divided by central corneal thickness multiplied by 33, further compared endothelial/Descemet’s membrane complex thickness with central corneal thickness.

Results:

Endothelial/Descemet’s membrane complex thickness, central corneal thickness, and Descemet’s rejection index were all able to differentiate between clear and rejected corneal grafts (p < 0.0001, p = 0.001, and p = 0.012, respectively). Endothelial cell density and coefficient of variation did not correlate with the clinical status (p = 0.054 and p = 0.102, respectively). Endothelial/Descemet’s membrane complex thickness had the largest area under the curve using receiver operating characteristic curves (p < 0.0001). Endothelial/Descemet’s membrane complex thickness had a sensitivity of 86% and specificity of 81% with a cutoff value of >16.0 µm (p < 0.0001). The sensitivity and specificity of endothelial cell density were both 71% with a cutoff value of ⩽897 cells/mm² (p = 0.053). There was a high correlation between endothelial/Descemet’s membrane complex thickness and both Descemet’s rejection index and central corneal thickness (p < 0.0001).

Conclusion:

Endothelial/Descemet’s membrane complex thickness measured by high-definition anterior segment optical coherence tomography is a useful parameter for the diagnosis of corneal graft rejection. The diagnostic performance of endothelial/Descemet’s membrane complex thickness was significantly better than that of endothelial cell density and central corneal thickness. Endothelial cell density and the coefficient of variation were unable to diagnose corneal graft rejection in our cross-sectional study.

Wasp sting of the cornea

Purpose

Many treatments, such as conservative management or penetrating keratoplasty, exist for corneal wasp sting. Here, we report a case of paper wasp sting of the cornea treated by anterior chamber wash immediately following admission, which soon resolved the inflammation.

Case

A healthy 9-year-old boy who had been stung by a paper wasp on his left eye 2 days prior to presentation at Dokkyo Medical University Saitama Medical Center was found to have corneal opacity accompanied by ciliary injection. The boy had difficulty opening his left eye due to pain. His left corneal endothelial cell density was 2,789 cells/mm², which was relatively lesser than that in the right eye. We diagnosed a paper wasp sting of the cornea based on both the patient’s clinical findings and sting history. The anterior chamber was promptly irrigated using a balanced salt solution; the inflammation resolved in a few hours, and the patient could open his left eye easily the following day. One day after the operation, the visual acuity improved to 1.2, and only slight corneal opacity remained at the original wasp sting site.

Conclusion

The positive outcome of the current case suggested that anterior chamber irrigation leads to rapid resolution of the inflammation.

Predictive Factors for Clinical Outcomes after Primary Descemet's Membrane Endothelial Keratoplasty for Fuchs' Endothelial Dystrophy

PURPOSE

The purpose of this study is to identify predictors for the best-corrected visual acuity (BCVA), central corneal thickness (CCT), and the endothelial cell density (ECD) after primary Descemet's membrane endothelial keratoplasty (DMEK).

METHODS

In a prospective observational study, 108 eyes with Fuchs' endothelial dystrophy underwent a primary DMEK. Preoperative data, histologic parameters from host's Descemet's membrane, and follow-up data of the first eye were analyzed in regard to BCVA, CCT, and ECD, 12 months after surgery.

RESULTS

Overall, 12 months postoperative, the BCVA improved to 0.11 ± 0.11 logMAR, the CCT declined to 529 ± 42 µm, and the ECD measured 1675 ± 418 cells/mm². A significant influence of the preoperative CCT on postoperative BCVAs and CCTs was observed (r = 0.299, p = 0.014 and r = 0.507, p < 0.001, respectively). Especially eyes with a CCT <625 µm demonstrated a better BCVA (0.05 ± 0.07 logMAR) than eyes with a CCT ≥625 µm (0.13 ± 0.11 logMAR, p = 0.002). Furthermore, the identification of eyes with an early visual restitution was possible by considering follow-up data of the first eye. A preoperative CCT ≥625 µm was also sensitive to identify eyes with a persistent corneal swelling. The anterior banded layer thickness, which was obtained histologically, correlated to the preoperative CCT and the frequency of graft detachments (r = 0.601, p = 0.023 and r = 0.652, p = 0.041, respectively). Furthermore, a graft's baseline ECD ≤2100 cells/mm² was found to be a risk factor for an ECD deterioration under 1000 cells/mm² (1.8% vs. 15.8%, p = 0.020).

CONCLUSIONS

Simple clinical parameters, such as the preoperative CCT, the course of visual restitution of the first eye, and the graft's baseline ECD, are efficient predictors for relevant outcome parameters after DMEK and therefore may be used for stratification. Furthermore, our findings indicate that a DMEK should be performed in eyes with Fuchs' endothelial corneal dystrophy, if possible, before the CCT exceeds 625 µm to maintain good clinical results.

Corneal integrity and thickness of central fovea after phacoemulsification surgery in diabetic and nondiabetic cataract patients

INTRODUCTION

Here we intended to investigate the changes in corneal endothelial cells and foveal thickness after phacoemulsification surgery on the eyes of diabetic and non-diabetic cataract patients.

MATERIAL AND METHODS

A total of 120 cataract patients who were scheduled for phacoemulsification surgery and intraocular lens implantation were recruited and divided into 2 categories according to the diagnosis of diabetes mellitus. Changes in integrity, endothelial cell density (ECD), coefficient of variation (CV), percentage of hexagonal cells (PHC), central corneal thickness (CCT), and central foveal thickness (CFT) were all recorded at preoperative day 1 and postoperative day 3, 1 week, 1 month, 3 months and 6 months.

RESULTS

None of the recorded variables showed any difference between the nondiabetic and diabetic groups before surgery (p > 0.05). During the postoperative 6 months, ECD and PHC decreased and CV increased in both groups (all p_time < 0.05), whereas CCT and CFT fluctuated in both groups significantly (both p_time < 0.05), with their individual peaks at postoperative 1 week in the diabetic group. The groups differed significantly in ECD, PHC, and CV at each time point postoperatively (all p_group < 0.05). Furthermore, the diabetic group had improved CFT during the postoperative 1 month and higher CCT during the 6 months postoperatively than the nondiabetic group (all p_group < 0.05). The time and group interactions were significant for ECD, CV, PHC, CCT and CFT (all p_{group × time} < 0.05).

CONCLUSIONS

The diabetic group had more changes in corneal endothelial cells and foveal thickness than the nondiabetic group postoperatively.

[Objective assessment of donor material for penetrating corneal transplantation]

Reliable suitability evaluation of donor material is the crucial issue of penetrating corneal transplantation. The main parameter to be considered is endothelial cell density (ECD). However, when it comes to practice, one has to admit significant variation in ECD readings of cadaver corneas obtained by different methods.

AIM

to investigate discrepancies in ECD measurements and to define objective criteria for the evaluation of a donor cornea before full-thickness grafting.

MATERIAL AND METHODS

In a hundred cadaver eyes, discrepancies in ECD measurements by different methods (specular microscopy, confocal microscopy, and keratoanalyzer) were studied and objective evaluation criteria developed along with an optimal algorithm of pretransplantation assessment. Digital fluorescence microscopy was chosen as the reference method.

RESULTS

It has been established that a triple measurement average obtained with any of the tested methods is informative enough as to the state of the donor cornea.

CONCLUSION

The highest ECD values were obtained with specular microscopy, the lowest - with confocal microscopy. For reliable evaluation of donor corneas, we recommend that the average of a triple ECD measurement be taken using one of the mentioned methods.

Endothelial Wound Repair of the Organ-Cultured Porcine Corneas

PURPOSE

To assess whether injured porcine endothelium of small and large corneoscleral disc differ in its reparative/regenerative capacity under various conditions of organ culture storage.

MATERIAL AND METHODS

166 paired porcine corneas were trephined to obtain tissues with diameter 12.0 mm and 17.5 mm (with area neighboring endothelial periphery). In tested discs, central endothelium was mechanically wounded. Density of live endothelial cells (LECD), percentage of dead cells (%DC), coefficient of variation and cell hexagonality were assessed in central and paracentral endothelium following 5- or 9-day incubation in medium with 2% or 10% fetal bovine serum. The parameters were assessed also in fresh and intact cultured discs. Dead endothelial cells (EC) were visualized by trypan blue, cell borders by Alizarin Red S dye. Endothelial imprints were immunoassayed for the proliferation marker Ki-67 and the nucleolar marker fibrillarin.

RESULTS

In fresh corneas, the LECD/mm² (mean ± standard deviation) were 3998.0 ± 215.4 (central area) and 3888.2 ± 363.1 (paracentral area). Only the length of storage had significant effect on wound repair. Lesion was repaired partially after 5-day and fully after 9-day cultivation. After 9-day storage in medium with 10% serum, the mean LECD detected in small discs were 2409.4 ± 881.8 (central area) and 3949.5 ± 275.5 (paracentral area) and in large discs the mean LECD were 2555.0 ± 347.0 (central area) and 4007.5 ± 261.2 (paracentral area). Ki-67 showed cell proliferation associated with healing of EC of both large and small corneas.

CONCLUSIONS

The lesions were completely repaired within 9 days of storage. Presence of the area, where stem cells appear to be located, contributes to stimulation of endothelial reparation less than serum concentration and time of culture. Both cell migration and proliferation contribute to the wound repair.

Investigation of importance of the structural parameters of the eyeball and of the technical parameters of cataract surgery on corneal endothelial changes

The aim of the here presented study was to look into the importance of the structural parameters of the eyeball, in relationship with the technical parameters of cataract surgery regarding the corneal endothelial changes made by it. Material and method: The paper refers at a prospective study in which we included eighty-eight consecutive eyes from eighty-six different patients having age-related cataract and a visual acuity of a values less than 0.8 considering best possible correction with it. The patients didn't have other obvious causes for the decreased visual acuity. The patients included in the present study were admitted at the Ophthalmology Department from Bucharest University Emergency Hospital between the month of April 2015 and February 2016 (ten months). Results: When we compared lots A, B with C, in regarding to the decrease of EDC, the results were relatively very similar. We had only one comparison for which we obtained a statistical significance, and that was for cataracts classified as group IV of hardness; here, between the first and the third lot, at seven days postoperatively we obtain p = 0.0472812. Conclusions: The conclusion for the present research was that in regarding cataract phaco-emulsification surgery we obtained a statistical significance when it comes to the destruction of epithelial cells. The results were observed, giving the depth of the anterior chamber, in cataracts classified in subgroup IV of hardness, only between patients who had a small depth of chamber comparing with those who had a large depth of the anterior chamber of the eye. When it comes to patients who had severe cataracts and small ACD, we need to attract more attention when the surgeon performs the maneuver and to keep an eye on the use of the adhesives which has viscoelastic in order to obtain additional corneal protection. Abbreviations: ACD = anterior chamber depth; ECD = endothelial cell density, EPT = effective time of phacoemulsification.

Posterior chamber phakic intraocular lens implantation: comparative, multicentre study in 351 eyes with low-to-moderate or high myopia

AIM

To compare the clinical outcomes of posterior chamber phakic intraocular lens implantation with a central hole (Hole Implantable Collamer Lens (ICL), STAAR Surgical) for low-to-moderate myopia and for high myopia.

METHODS

This multicentre retrospective case series comprised 351 eyes of 351 consecutive patients undergoing ICL implantation. Eyes were divided into groups based on preoperative degree of myopia: group 1; 57 eyes, manifest spherical equivalent less than -6 dioptres (D), and group 2; 294 eyes, -6 D or more. Safety, efficacy, predictability, stability and adverse events were compared preoperatively; and at 1 day, 1 week and 1, 3, 6 and 12 months postoperatively, RESULTS: Uncorrected and corrected visual acuities were -0.17±0.14 and -0.21±0.10 logMAR in group 1, and -0.16±0.09 and -0.21±0.08 logMAR in group 2, 1 year postoperatively. In groups 1 and 2, 98% and 99% of eyes were within 1.0 D of the targeted correction. Manifest refraction changes of -0.12±0.34 D (group 1) and -0.18±0.43 D (group 2) occurred from 1 day to 1 year. ICL exchanges were necessary in two eyes (0.7%) in group 2. No vision-threatening complications occurred at any time.

CONCLUSIONS

The ICL performed well for the correction of both low-to-moderate myopia and high myopia throughout the 1-year observation period. The clinical outcomes of ICL implantation for low-to-moderate myopia are essentially equivalent to those for high myopia.

Corneal endothelium and central corneal thickness changes in type 2 diabetes mellitus

PURPOSE

This study was conducted to compare the corneal endothelial cell density (ECD), morphological features, and central corneal thickness (CCT) in type 2 diabetes mellitus (DM) with age-matched, nondiabetic control subjects using EM-3000 Specular Microscope.

STUDY DESIGN

This was a prospective, hospital-based, nonrandomized, case-control, observational, and quantitative study.

SUBJECTS AND METHODS

The study included 57 patients (57 eyes) with type 2 DM and 45 control (nondiabetic) subjects (45 eyes). The corneal endothelial structure and CCT were examined in all eyes by noncontact specular microscopy using EM-3000 Specular Microscope. The endothelial structure was studied for ECD, coefficient of variation of cell area (CV), and percentage of hexagonal cells.

RESULTS

The study included 36 eyes without diabetic retinopathy (DR), 14 eyes with nonproliferative DR, and 7 eyes with proliferative DR. There were 26 eyes with a duration of ≤10 years and 31 eyes with a duration of >10 years. Also, there were 24 eyes with HbA_1c ≤7.5% and 33 eyes with HbA_1c >7.5%. ECD was significantly lower in the diabetic cornea than in control group (P=0.014). CV was higher in diabetic cornea (P=0.008). The diabetic cornea group had lower percentage of hexagonal cells than the control group, but the difference was not statistically significant (P=0.603). Also, diabetic cornea was thicker than control group, but not statistically significant (P=0.301).

CONCLUSION

This study documented that type 2 DM causes a significant reduction of ECD and increased CV (polymegathism). Also, diabetic cornea has increased CCT and lower percentage of hexagonal cells than normal subjects, but without statistical significance.

Endothelial cell loss in penetrating keratoplasty, endothelial keratoplasty, and deep anterior lamellar keratoplasty

PURPOSE:

To compare endothelial cell density (ECD) loss rates in penetrating keratoplasty (PKP), Descemet's stripping automated endothelial keratoplasty (DSAEK), and deep anterior lamellar keratoplasty (DALK).

DESIGN:

Single-center, multiple-surgeon, retrospective cohort study.

MATERIALS AND METHODS:

Patients who received PKP, DSAEK, or DALK from 2009 to 2014 were analyzed (68 vs. 38 vs. 11 patients, respectively). We excluded patients with therapeutic PKP or regraft, infection, endothelial rejection, or uncontrolled glaucoma. Only clear grafts and initial ECD more than 1000 cell/mm² were included in the study. The main outcome was ECD loss rate. The follow-up time period was divided into five subgroups: 0–1.5 months, 1.5–6 months, 6–12 months, 12–24 months, and longer than 24 months.

RESULTS:

Average ECD loss rate (cell/mm²/month) declined in all three groups (PKP group: −561.5, −113.2, −36.6, −31.4, and −53.7; DSAEK group: −686.4, −68.3, −21.8, −14.4, and −5.1; DALK group: −576.5, −68, −23.7, 5.9, and 18.3). Although DSAEK group showed faster ECD loss rate in the early postoperative period, it became slower compared to the PKP group within the postoperative 6^th month and demonstrated significant difference within 2 years. No ECD loss developed in the DALK group after the 1^st postoperative year; this was significantly different from the PKP group.

CONCLUSIONS:

Although ECD loss rate in the DSAEK group was initially larger than that in the PKP group, the DSAEK group possessed better long-term endothelial cell survival rate. The DALK group had a lower ECD loss rate than that of the other groups and maintained a stable ECD at 1 year after surgery.

Trabeculectomy with or without Anterior Chamber Maintainer: A Study on Intraocular Pressure, Endothelial Cells, and Central Corneal Thickness

PURPOSE

To compare the impact of trabeculectomy and trabeculectomy with an anterior chamber (AC) maintainer on intraocular pressure (IOP), endothelial cell density (ECD), and central corneal thickness (CCT) in patients with primary open angle glaucoma (POAG).

METHODS

The two groups consisted of 36 (trabeculectomy, Group A) and 42 (trabeculectomy with AC maintainer, Group B) patients with POAG. IOP, CCT, and ECD were measured one day prior to surgery, one month, six months, and 12 months postoperatively.

RESULTS

No complications were observed. The mean decrease of mean IOP from baseline to 12 months was statistically significant for both groups (all p < 0.0001), but more significant in Group B (p = 0.01). ECD decrease was significant in both Groups (all p < 0.01), but more significant in Group A (p < 0.0001). CCT decrease was also greater in Group A (p < 0.0001). The surgical procedure's duration was significantly longer in Group B than in Group A (p < 0.0001).

CONCLUSIONS

Both techniques seem to be effective and safe options for patients with POAG. Using an AC maintainer might add some safety for the ECD and a bit greater IOP reduction; however, the classic technique, which is of less complexity and less time-consuming, has comparable results.

Normal corneal endothelial cell density in Nigerians

Aim

The aim of the study was to describe the corneal endothelial cell density of adults at the MeCure Eye Center and to determine the relationship between age, sex, and corneal endothelial cell density.

Methods

This study was a retrospective study looking at those records of individuals who had undergone specular microscopy or corneal endothelial cell count measurement at the MeCure Eye Center.

Results

The endothelial cell characteristics of 359 healthy eyes of 201 volunteers were studied. The mean corneal endothelial cell density (MCD) was 2,610.26±371.87 cells/mm² (range, 1,484–3,571 cells/mm²). The MCD decreased from 2,860.70 cells/mm² in the 20–30-year age group to 2,493.06 cells/mm² in the >70-year age group, and there was a statistically significant relationship between age and MCD with a P-value of <0.001. There was no statistically significant correlation between sex and corneal endothelial cell density (P=0.45).

Conclusion

This study shows that endothelial cell density in Nigerian eyes is less than that reported in the Japanese, American, and Chinese eyes, and is comparable to that seen in Indian and Malaysian eyes.

Changes in corneal endothelium cell characteristics after cataract surgery with and without use of viscoelastic substances during intraocular lens implantation

PURPOSE

To evaluate whether the use of balanced salt solution (BSS) or an ophthalmic viscoelastic device (OVD) during hydrophilic acrylic intraocular lens (IOL) implantation variously impacts corneal endothelial cell characteristics in eyes undergoing uneventful phacoemulsifications.

METHODS

Prospective nonrandomized observational clinical trial. Patients were assigned either to the BSS plus(®) or to the OVD Z-Celcoat™ group depending on the substance used during IOL implantation. Corneal endothelium cell characteristics were obtained before, 1 week, and 6 weeks after surgery. Intraoperative parameters (eg, surgery time, phacoemulsification energy) were recorded.

RESULTS

Ninety-seven eyes were assigned to the BSS plus and 86 eyes to the Z-Celcoat group. Preoperative corneal endothelium cell density (ECD) and endothelium cell size were 2,506±310 cells/mm(2)/2,433±261 cells/mm(2) and 406±47 µm(2)/416±50 µm(2) (P=0.107/P=0.09). After 1 and 6 weeks, ECD decreased and endothelium cell size increased significantly in both groups (each P<0.001) without significant differences between both groups (each P>0.05). Irrigation-aspiration suction time (30.3±16.6 versus 36.3±14.5 seconds) and overall surgical time (7.2±1.2 versus 8.0±1.4 minutes) were significantly longer in the OVD Z-Celcoat group (each P<0.001). No complications or serious side effects occurred.

CONCLUSION

Implantation of a hydrophilic acrylic IOL under BSS infusion seems to be a useful and faster alternative in experienced hands without generating higher ECD loss rates.