Stromal Hydration Research Articles

Assessment And Comparison of Bacterial Contamination in Anterior Chamber Aspirates in Small Incision Cataract Surgery (SICS) And Phaco-Emulsification

Introduction: The rate of occurrence of endophthalmitis after cataract surgery has been reduced to a greater extent now a day. Even then endophthalmitis related consequences are devastating. Several sources of infection, including contamination by air, solutions, surgical instruments, intraocular lens, and wound leakage have been identified. Aim of the Study: The study aimed to evaluate the influence of two methods of surgical technique of cataract surgery in bacterial as well as comparison of contamination by these two techniques. Methods: This prospective observational study was conducted over 60 patients with age related cataract in the department of Ophthalmology and Microbiology in Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh, from 1st January, 2009 to 30th June, 2009. Patients were selected purposively based on specific selection criteria. Selected patients underwent detail ophthalmic and systemic evaluation as well as relevant investigations. Cataract extraction followed by intraocular lens implantation was planned for all patients. The two techniques of cataract surgery such as SICS and Phacoemulsification were assigned to the patients randomly by 1:1 basis. 1 ml of anterior chamber contents were aspirated through aseptic technique by 26G needle from each patient pre-operatively, after capsulorrhexis (early per-operative) and just before wound closure by stromal hydration (late per-operative). All samples were sent for 10% KOH staining and culture and sensitivity test after proper leveling. Results: Micro-biological examination shows no sample was positive for 10% KOH staining. In SICS group, out of 30 samples 3 were found culture positive, which were positive in 4 and 5 samples in early per-operative and late per-operative sample respectively and in Phacoemulsification group, it was 2, 3, 5 pre-operative, early per-operative and late per-operative sample respectively. The common organisms isolated were Coagulase positive Streptococcus, Corynebacterium species, Streptococcus viridans, and Staphylococcus aureus etc. Almost none of the patients showed clinical activity except few cells and flare in the anterior chamber in early post-operative period. Conclusion: The microbiological examination shows the incidence of microbial contamination of anterior chamber contents is very low after cataract surgery by both form of technique, and there was no statistically significance difference in incidence between these two techniques. J.Natl.Inst.Ophthalmol.2023;6(1): 37-41

Preparation and evaluation of a suspension of human corneal endothelial cells isolated from the eyes of cadaveric donors for transplantation in an <em>ex vivo</em> experiment

Background. According to the World Health Organization, corneal diseases are one of the major causes of blindness globally. Endothelial dystrophy is one of the etiological factors leading to corneal diseases. The corneal endothelium is a monolayer of cells with virtually no mitotic activity. When the density of corneal endothelial cells falls below a critical threshold, the endothelium loses its ability to regulate corneal stromal hydration. This leads to corneal clouding and, consequently, to reduced visual acuity and quality of life of the patient. In this regard, various keratoplasty methods are widely used in clinical practice. Today, it is technically possible to transplant all corneal layers via penetrating keratoplasty, and to transplant the posterior epithelium via layer-bylayer keratoplasty. These surgical approaches are now widely used in everyday practice, but they require the use of scarce material – cadaveric donor corneas, from which grafts for the above-mentioned operations are formed in the conditions of an eye bank. In this regard, protocols for obtaining human corneal endothelial cell (HCEC) culture for subsequent transplantation have been proposed in recent years. However, the use of such approaches in Russia is limited by the law. The aim of this study was to experimentally justify the possibility of transplanting uncultured endothelial cells, isolated from cadaveric human corneas. Materials and methods. The first stage of the work consisted of obtaining a suspension of endothelial cells from cadaveric donor corneas and studying it; at the second stage, the transplantation effectiveness of the resulting cell suspension was assessed in an ex vivo experiment. Results. The cell phenotype after transplantation by the proposed method had high viability and preservation. Conclusions. The presented results suggest that phenotype and adhesion ability are preserved, and that the cell suspension has a high level of viability under adequate loss of endothelial cells during transplantation in the ex vivo experiment.

Bacterial Contamination Evaluation in Anterior Chamber Aspirates: Contrasting Small Incision Cataract Surgery (SICS) and Phacoemulsification

Introduction: The rate of occurrence of endophthalmitis after cataract surgery has been reduced to a greater extent nowadays. Even then endophthalmitis related consequences are devastating. Several sources of infection, including contamination by air, solutions, surgical instruments, intraocular lenses, and wound leakage have been identified. Aim of the Study: The study aimed to evaluate the influence of two methods of surgical technique of cataract surgery in bacterial as well as comparison of contamination by these two techniques. Methods: This prospective observational study was conducted over 60 patients with age-related cataracts in the Department of Ophthalmology and Microbiology in Sir Salimullah Medical College and Mitford Hospital, Dhaka, Bangladesh, from 1st January 2009 to 30 June 2009. Patients were selected purposively based on specific selection criteria. Selected patients underwent detailed ophthalmic and systemic evaluation as well as relevant investigations. Cataract extraction followed by intraocular lens implantation was planned for all patients. The two techniques of cataract surgery such as SICS and Phacoemulsification were assigned to the patients randomly on a 1:1 basis. 1 ml of anterior chamber contents were aspirated through an aseptic technique by 26G needle from each patient pre- operatively, after capsulorhexis (early per-operative), and just before wound closure by stromal hydration (late per- operative). All samples were sent for 10% KOH staining and culture and sensitivity test after proper leveling. Results: Micro-biological examination shows no sample was positive for 10% KOH staining. In the SICS group, out of 30 samples, 3 were found culture positive, which were positive in 4 and 5 samples in early per-operative and late per-operative samples respectively, and in the Phacoemulsification group, it was 2, 3, 5 pre-operative, early per- operative and late per-operative sample respectively. The common organisms isolated were ......

Comparing morphologic features and complications of main clear corneal incision between junior and senior residents observed using anterior segment optical coherence tomography.

Wound construction is a critical step in phacoemulsification. Using anterior segment optical coherence tomography (AS-OCT), we compared the morphological features and complications of main incisions made by junior or senior residents during phacoemulsification. This cross-sectional comparative study included eyes with senile cataracts that underwent uneventful phacoemulsification with a clear corneal incision made by seven senior and eight junior ophthalmology residents. All eyes underwent postoperative image acquisition using AS-OCT on day one and at three months, examining for morphological features and potential complications of the main incision. We included 50 eyes of 50 patients with a male-to-female ratio of 22 (44%) to 28 (56%); 26 (52%) were operated on by junior residents and 24 (48%) by seniors. The mean geometric features of the main incisions and the frequency of early and late wound complications were comparable between the two groups (all P > 0.05). A significant correlation was found between the incision length and angle with the superior (r = + 0.80; P < 0.001 and r = - 0.63; P < 0.001, respectively) and inferior (r = + 0.84; P < 0.001 and r = - 0.68; P < 0.001, respectively) areas of the incision, as well as between the length and angle of incision (r = - 0.74; P < 0.001). The number of planes in the wound architecture was not significantly different according to senior or junior resident status (P > 0.05). Although the number of eyes with stromal hydration was significantly greater for junior residents than for seniors (P < 0.001), the corneal thickness at the entrance to the cornea or the anterior chamber, presence of endothelial wound gaping, and Descemet's membrane detachment were comparable between eyes with and without stromal hydration (all P > 0.05). At three months, 29 (58%) patients returned for examination, in whom seven (24%) had late wound complications. This study found no significant differences in the performances of junior and senior residents in terms of wound construction or its associated complications. However, considering the overall rate of some observed wound-related complications, we recommended revision of the resident educational curriculum concerning the structure and complications of the main incision.

Swab Pressing vs Stromal Hydration to Prevent Incision Leakage and Transient Collapse of Anterior Chamber in Phacoemulsification

During phacoemulsification, incision leakage and the subsequent anterior chamber collapse often occur after the withdrawal of the handpiece, which cannot be prevented by current sealing techniques. A new technique called swab pressing is proposed here to apply pressure with a cotton swab to seal the incision immediately, but efficacy remains unknown. To determine if swab pressing is noninferior to stromal hydration, the current practice, in sealing incisions in phacoemulsification for age-related cataract. This noninferiority randomized controlled clinical trial was conducted between February 2022 and September 2022 at the Zhongshan Ophthalmic Center, Guangzhou, China. Patients aged 60 to 90 years with age-related cataract were enrolled. Participants were randomly assigned (1:1) to receive swab pressing or stromal hydration. All surgeries were performed by a single experienced surgeon who was unmasked to the assignment. The proportion of closed clear corneal incisions evaluated using intraoperative optical coherence tomography. A total of 126 eyes of 126 participants were randomized into the swab pressing group (63 [50%]) and stromal hydration group (63 [50%]). The mean (SD) age of participants was 69.2 (6.14) years and 70.1 (7.67) years in the pressing and stromal hydration groups, respectively. A total of 39 participants (61.9%) in the pressing group and 35 (55.6%) in the modified group were female. The proportion of closed incisions was 96.8% (61 of 63) in the swab pressing group and 93.7% (59 of 63) in the stromal hydration group. Noninferiority was met, as the lower 95% CI of -5.83 percentage points was greater than the prescribed noninferiority margin of -6.60 percentage points (difference, 3.17 percentage points; 95% CI, -5.83 to 12.18 percentage points). The rate of anterior chamber collapse (pressing: 0 of 63 vs stromal hydration: 35 of 63 [55.6%]; P < .001) was lower in the swab pressing group. There were no differences between the 2 groups in the proportion of closed incisions and central anterior chamber depth at postoperative hour 1 and day 1. In this study, swab pressing was noninferior to stromal hydration in sealing clear corneal incisions in phacoemulsification for age-related cataract. While this trial involved only 1 surgeon who was not masked to the interventions, the results suggest that swab pressing is feasible and further investigations would be warranted to determine if it prevents the intraoperative transient collapse of anterior chamber or affects visual acuity outcomes. ClinicalTrials.gov Identifier: NCT05242653.

A Modified Technique for Preventing Lens-Iris Diaphragm Retropulsion Syndrome in Vitrectomized Eyes during Phacoemulsification.

Lens-iris diaphragm retropulsion syndrome (LIDRS) is common in vitrectomized or high myopic eyes during phacoemulsification. We evaluated the results of a modified technique for cataract treatment using phacoemulsification in vitrectomized eyes. In this retrospective study, we enrolled thirty-four vitrectomized eyes treated with modified phacoemulsification (Modified Group) and nineteen vitrectomized eyes treated with routine phacoemulsification (Control Group). The modified technique comprised irrigation with a balanced salt solution underneath the pupil before phacoemulsification instrument entry, lens implantation and stromal hydration to stabilize the anterior chamber and equilibrate the pressure between the anterior chamber and posterior cavity. We compared the incidences of intra and postoperative complications and visual outcomes between modified and routine phacoemulsification. Pain, LIDRS and difficulty in stromal hydration were significantly more common in the Control Group than in the Modified Group (p < 0.05). There were no significant differences in the rates of posterior capsular rupture, iris trauma, lens dislocation, or posterior capsular opacification between the Modified and Control Groups (p > 0.05). However, there was no significant difference in visual acuity between the groups (p > 0.05). Complications such as loss of nuclear fragments into the vitreous cavity, cystoid macular edema, retina redetachment, suprachoroidal hemorrhage and vitreous hemorrhage did not occur either intra or postoperatively in any of our patients. Our modified technique prevents LIDRS and complications arising during cataract surgery in vitrectomized eyes. Aside from this, the results of modified and routine phacoemulsification are similar in vitrectomized eyes.

Successful Management of Intraoperative Toxic Endothelial Cell Destruction During Routine Manual Small-incision Cataract Surgery

Cataract surgery is one of the most commonly performed ophthalmic surgeries worldwide. Stromal hydration is done to improve the integrity of the wound, reform the anterior chamber at the end of the surgery and obtain a water-tight wound closure to reduce the risk of endophthalmitis. At the completion of the surgery, subconjunctival injections of antibiotics and steroids are commonly given to reduce the risk of endophthalmitis. Intracameral injection of antibiotics is the delivery of drugs to prevent endophthalmitis, but if a wrong drug is injected in the anterior chamber, it can result in endothelial and anterior chamber toxicity. Here we report a rare and interesting case of a 60-year-old female who underwent manual small-incision cataract surgery (MSICS) for nuclear sclerosis grade 3. All the steps of the surgery were uneventful. At the end of the surgery, side port stromal hydration was performed, and while injecting intracameral moxifloxacin wrongly, gentamicin and dexamethasone were injected into the stroma and anterior chamber. The patient developed 3 + striate keratopathy postoperatively, which was managed with tapering doses of topical steroids, hypertonic saline, and adjuvant drugs. The endothelial cell toxicity resolved within three weeks, and the patient’s vision returned to 6/6. This case signifies that an intraoperatively wrong drug can be injected intracamerally, resulting in transient endothelial cell toxicity, which, if managed correctly, can give an excellent outcome.

A comparative study of endothelial cell loss in small incision cataract surgery versus phacoemulsification cataract surgery by using specular microscope at tertiary care ophthalmic centre in Bengaluru, Karnataka

Most commonly performed surgical procedure in Ophthalmology is cataract extraction by MSICS and Phacoemulsification. It has always been associated with damage to endothelium of cornea, a layer which is vital for maintaining corneal transparency. The corneal endothelium regulates stromal hydration and maintains the transparency of the cornea by constantly removing the fluid out of the corneal stroma. The density of corneal endothelial cells and its integrity is an important determinant for corneal transparency. Post-operative corneal decompensation leading to reduced visual acuity can occur as a result of this surgical trauma. Hence it is necessary to determine the surgical technique safest to corneal endothelium. Specular microscopy helps to determine this corneal endothelial cell density. A hospital based longitudinal study was done from November 2017 to May 2019 in 124 patients at Minto Ophthalmic Hospital. 62 patients underwent MSICS and 62 phacoemulsification. After a written informed consent patients were evaluated with detailed history, slit lamp examination, direct and indirect ophthalmoscopy, biometry, lacrimal syringing, IOP measurement with tonometry and endothelial cell count was evaluated using non contact specular microscopy preoperatively and postoperative 1 week and 6 weeks. Statistical data analysed by unpaired – t test. The mean ECC (cells/mm) in MSICS and phacoemulsification group preoperatively was 2486.82 + 152.730 and 2433.71 + 192.692 respectively. The mean endothelial cell loss (cells/mm) was 314.61 + 64.428 and 324.31 + 30.67 at 1 week and 345.71 + 66.68 and 354.95 + 53.885 at 6 weeks postoperatively between the two groups. The endothelial cell loss was not statistically significant at 1 week (p -0.28) and 6 weeks (p-0.39) postoperatively between the two groups. There was no clinically or statistically significant difference in the endothelial cell loss between MSICS and Phacoemulsification. As MSICS is economical and less dependent on technology, it can be a safe option in developing world.

CHIR99021 balance TGFβ1 induced human corneal endothelial-to-mesenchymal transition to favor corneal endothelial cell proliferation

Corneal endothelial cells (CECs) play a major role in the maintenance of stromal hydration via the barrier and pump function for clear vision. Adult CECs cannot regenerate after injury. CECs cultured in vitro can undergo mitosis but may undergo corneal endothelial-to-mesenchymal transition (EnMT) and lose their endothelial characteristics. In this study, we examined the effects of CHIR99021 on transforming growth factor beta-1(TGFβ1)-induced EnMT in human CECs (hCECs) lines. CHIR99021 kept hCECs in the hexagonal shape and could downregulate the EnMT markers alpha-smooth muscle actin (α-SMA) and fibronectin (FN1), meanwhile maintained the hCECs function markers Na+/K+-ATPase and zonula occludens-1 (ZO-1) at levels comparable to those in the normal control. Interestingly, we found that the combination of CHIR99021 and TGFβ1 at appropriate concentrations would significantly promote the proliferation and migration of hCECs. These effects may be related to the inhibition of RhoA or Rac1, as well as the activation of Wnt and Erk pathway, with a calcium homeostasis. Our findings indicate that CHIR99021 inhibit EnMT and that the combination of CHIR99021 and TGFβ1 may provide new ideas for corneal endothelial regeneration and wound healing.

A novel corneal adhesive based on functionally coupled PEG-lysozyme hydrogel for wound closure after surgical eye surgery

Corneal wound closure for surgical eye surgeries or accidents is typically performed to prevent pathogens from the sterile intraocular environment and avoid potential postoperative complications. Tissue adhesives are increasingly employed for corneal wound closure with superior treatment efficiency and less adverse effects. In this study, we successfully develop a novel corneal adhesive based on functionally coupled PEG-lysozyme (PEG-LZ) hydrogels for wound closure after surgical eye surgeries. PEG-LZ hydrogels have plenty of micropores and gradually decreased pore size with increasing concentration from 10%, 15% to 20% (w/v), in which PEG-LZ (15%) represents the suitable pH value, gelation time and elastic modulus. PEG-LZ hydrogels have no in vitro cytotoxicity and excellent ex vivo wound closure effectiveness in porcine eyes. The in vivo wound sealant in rabbit eyes by PEG-LZ hydrogels presents a superior therapeutic effect compared with the conventional methods of stromal hydration and suture, in terms of the wound closure percent, mean corneal thickness, percent of wound gaping, and the Descemet membrane detachment. PEG-LZ hydrogels do not induce obvious histological pathology changes. The PEG-LZ corneal adhesive is considered as a tissue adhesive alternative for wound closure after surgical eye surgeries.

I-PDEK: Microscope-integrated OCT-assisted pre-Descemet endothelial keratoplasty.

Four patients with pseudophakic corneal edema were subjected to pre-Descemet endothelial keratoplasty (PDEK) under the direct guidance of microscope-integrated optical coherence tomography (i-OCT). i-OCT facilitated successful type 1 big bubble formation during donor preparation, debridement of the hypertrophic epithelium, planning and placement of surgical wounds, descemetorrhexis with removal of remnant Descemet membrane tags, and identification of correct donor orientation and interface details. It was also possible to discern the stability of intraocular lens, flat iris configuration, adequate stromal hydration, and wound apposition on i-OCT. Preoperative visual acuity was counting fingers (50%), 0.78 logMAR (25%), and 1.48 logMAR (25%), whereas postoperative visual acuity was 0.6 logMAR (50%) and 0.3 logMAR (50%). At 6-months of follow-up, all grafts were clear and well attached, the mean central corneal thickness, graft size, graft thickness, and endothelial cell loss were 557.25 ± 13.45 μm, 7.75 ± 0.20 mm, 25.5 ± 2.64 μm, and 21.6 ± 0.02%, respectively. To conclude, i-OCT helped during various surgical steps of PDEK.

Recent Advances in Hydrogels: Ophthalmic Applications in Cell Delivery, Vitreous Substitutes, and Ocular Adhesives.

With the prevalence of eye diseases, such as cataracts, retinal degenerative diseases, and glaucoma, different treatments including lens replacement, vitrectomy, and stem cell transplantation have been developed; however, they are not without their respective shortcomings. For example, current methods to seal corneal incisions induced by cataract surgery, such as suturing and stromal hydration, are less than ideal due to the potential for surgically induced astigmatism or wound leakage. Vitrectomy performed on patients with diabetic retinopathy requires an artificial vitreous substitute, with current offerings having many shortcomings such as retinal toxicity. The use of stem cells has also been investigated in retinal degenerative diseases; however, an optimal delivery system is required for successful transplantation. The incorporation of hydrogels into ocular therapy has been a critical focus in overcoming the limitations of current treatments. Previous reviews have extensively documented the use of hydrogels in drug delivery; thus, the goal of this review is to discuss recent advances in hydrogel technology in surgical applications, including dendrimer and gelatin-based hydrogels for ocular adhesives and a variety of different polymers for vitreous substitutes, as well as recent advances in hydrogel-based retinal pigment epithelium (RPE) and retinal progenitor cell (RPC) delivery to the retina.

Efficacy of Nepafenac versus Flurbiprofen in Maintaining Intraoperative Mydriasis During Phacoemulsification: A Comparative Study.

PurposeTo compare the efficacy of topical nepafenac (0.1%) with flurbiprofen (0.03%) in maintaining intra-operative mydriasis during phacoemulsification surgery.Patients and MethodsThis study comprised of 160 patients, who were divided into two arms of 80 each (arms A and B) after randomisation. Pre-operatively, all patients received one drop of tropicamide 0.8% and phenylephrine 5% (combination), 4 times, at an interval of 15 minutes on the day of surgery. Thereafter, Nepafenac drop in arm A/Flurbiprofen drop in arm B was administered 4 times, at an interval of 15 minutes keeping a gap of 10 minutes between tropicamide-phenylephrine and any of the experimental drugs. Phacoemulsification was performed one hour after the administration of last drop. Both vertical and horizontal pupillary diameter were measured at three steps; immediately before the surgical incision (baseline), at the end of emulsification of nucleus (before irrigation and aspiration) and at the end of surgery (after stromal hydration).ResultsThe difference in pupillary diameter between two groups, was statistically insignificant for vertical diameter (P = 0.08) and horizontal diameter (P = 0.28) at the start of surgery. On the other hand, pupillary diameter difference was statistically significant after emulsification of nucleus and at the end of surgery as well when both vertical (P < 0.05) and horizontal diameter (P < 0.05) were considered. The total reduction in pupillary diameter (both vertically and horizontally) was significantly less in the Nepafenac as compared to Flurbiprofen group (P < 0.05). Analysis of mean cumulative dissipated energy did not document any appreciable difference between the two groups. Phacoemulsification time analysis yielded statistically significant results (P = 0.004) between the Nepafenac and Flurbiprofen group.ConclusionIn the present study, topical Nepafenac (0.1%) proved to be more efficacious in maintaining intra-operative mydriasis during phacoemulsification surgery as compared to topical Flurbiprofen (0.03%).

Diseases of the corneal endothelium

The corneal endothelial monolayer and associated Descemet's membrane (DM) complex is a unique structure that plays an essential role in corneal function. Endothelial cells are neural crest derived cells that rest on a special extracellular matrix and play a major role in maintaining stromal hydration within a narrow physiologic range necessary for clear vision. A number of diseases affect the endothelial cells and DM complex and can impair corneal function and vision. This review addresses different human corneal endothelial diseases characterized by loss of endothelial function including: Fuchs endothelial corneal dystrophy (FECD), posterior polymorphous corneal dystrophy (PPCD), congenital hereditary endothelial dystrophy (CHED), bullous keratopathy, iridocorneal endothelial (ICE) syndrome, post-traumatic fibrous downgrowth, glaucoma and diabetes mellitus.

Wound integrity of modified anterior stromal hydration Vs. conventional hydration after clear corneal incision phacoemulsification.

Purpose:To compare the self-sealing ability of temporal clear corneal incisions for phacoemulsification using conventional stromal hydration (CH) with two modified methods: the anterior stromal pocket hydration (ASPH) and the modified stromal pocket hydration (MASH).Methods:Patients undergoing routine phacoemulsification surgeries were randomized to receive the CH, ASPH, and MASH (n = 30 eyes in each group). In the ASPH, an anterior stromal pocket was created superficial and parallel while in the MASH; it was superficial and perpendicular to the plane of the main incision. The primary outcome measure was wound leakage assessed after applying firm downward pressure on the posterior lip of the main corneal incision, simulating eye rubbing.Results:On application of pressure to the posterior lip, leakage was seen from 19 eyes (63%) in the CH group, while this was seen in only two eyes (7%) each in the ASPH and MASH groups (P < 0.001). The likelihood of wound leak after applying pressure to the posterior lip reduced by 86% in the ASPH and MASH groups compared to CH (Odds ratio = 0.14, 95% CI = 0.05 – 0.35, P < 0.001). The mean surgically induced astigmatism was 0.18 ± 0.14D and there were no differences in SIA across the three groups (P = 0.42). More eyes in the ASPH required conversion to CH (n = 4, 13%) due to difficulty in localizing the pocket compared to MASH (n = 0, P = 0.03)Conclusion:Both, the ASPH and MASH techniques reduce the risk of wound leakage and do not induce astigmatism. The MASH technique makes it easier to consistently localize the pocket.

Incidence and causes of negative dysphotopsia after uncomplicated cataract surgery – A randomized clinical trial

Purpose:The purpose of this study is to find incidence of negative dysphotopsia (ND) in eyes undergoing clear corneal phacoemulsification and identify its causes including corneal wound hydration and type of intraocular lens (IOL).Methods:In this randomized clinical trial, consenting adult patients undergoing phacoemulsification were randomized to receive a hydrophobic (Alcon Acrysof® SN60WF) or a hydrophilic acrylic IOL (CT Asphina® 603P, Carl Zeiss Meditec) in a 1:1 ratio. At time of surgery, eyes were again randomized in 1:1 fashion to receive stromal wound hydration or not (n = 80 each in four groups). Primary outcome measure was the incidence of ND between eyes receiving stromal hydration versus no hydration. Those with ND were observed for 5 years after surgery.Results:Of the 320 eyes, 29 (9.06%) reported ND of which 24 (83%) were transient. Eyes with wound hydration had significantly higher proportion of ND (n = 21/160, 13%) compared to no hydration (n = 8/160, 5%) (P = 0.01). Additionally, eyes with wound hydration were three times more likely to experience ND (odds ratio = 3.29, 95% CI = 1.3–8.2, P = 0.01). Majority of eyes (20/21, 95%) with ND after hydration had it transiently while half (4/8, 50%) of those with ND without wound hydration had it persistently at 6 weeks (P < 0.001) and continued to experience ND for 5 years but did not request intervention.Conclusion:ND occurred in 9% cases with majority being transient. Corneal wound hydration led to significant higher likelihood of experiencing transient ND. Those with persistent ND for more than 6 weeks (1.5%) continue to experience ND for at least 5 years.

Intraoperative Optical Coherence Tomography Analysis of Clear Corneal Incision: Effect of the Lateral Stromal Hydration.

Methods The cohort included 65 clear corneal incisions of 49 patients who underwent cataract surgery. Corneal incisions were recorded using a Leica Proveo 8 microscope with an intraoperative OCT EnFocus™ device continuously during the surgery. Corneal incision morphology before and after lateral stromal hydration was analysed. Results Good adaptation of the corneal incision before hydration was present in 39 cases (60%), in 16 cases (24.6%), the prominence of posterior lip was present, and, in 10 cases (15.4%), the posterior lip tongue was inverted/retracted into the incision. In 38 cases (58.5%), hydration had no effect on the incision architecture; most often, it was primarily a well-adapted corneal incision (46.2%), less often an incision with posterior lip prominence (10.8%), or tongue inversion into the incision (1.6%) prior to hydration. Hydration worsened the incision architecture in 14 cases (21.5%); most often, it induced/worsened posterior lip prominence (15.4%), less often posterior lip retraction (1.6%), tongue inversion into the incision (1.6%), gap development in the peripheral part of the corneal incision (1.6%), or incomplete opening of the corneal incision (1.6%). In 13 cases (20%), hydration improved the incision architecture, especially in cases with inverted or retracted posterior lip tongue (12.3%), less often in cases with posterior lip prominence (7.7%). Conclusion Lateral stromal hydration seldom affects the condition of the corneal incision. Still, it can cause both deterioration and improvement of the corneal incision architecture. Intraoperative OCT provides real-time monitoring of corneal incision morphology during hydration procedure.

Mechanism of fluid leak in non-traumatic corneal perforations: an anterior segment optical coherence tomography study

AimNon-traumatic corneal perforations (CPerfs) may present with shallow/flat or formed anterior chamber (AC). This study uses anterior segment optical coherence tomography (ASOCT) to ascertain these differences.MethodThe study included 14 eyes...

Limbal Metabolic Support Reduces Peripheral Corneal Edema with Contact-Lens Wear.

PurposeTo assess the influence of limbal metabolic support on corneal edema during scleral-lens (SL) and soft-contact-lens (SCL) wear for healthy lens wearers.MethodsA two-dimensional (2D) model of the cornea and sclera was designed on Comsol Multiphysics 5.4 along with SL and SCL architectures to mimic lens-wear induced hypoxia. The cornea is suffused with oxygen and metabolites from the limbus and aqueous humor. Air oxygen is supplied from and carbon dioxide is expelled to the atmosphere. Lens-oxygen permeability (Dk) was adjusted to investigate lens-wear safety against edema in different wear conditions. The 2D concentrations of oxygen, carbon dioxide, bicarbonate, lactate, sodium, chloride, glucose, and pH are quantified. Central-to-peripheral swelling of the cornea is determined by the change in stromal hydration caused by changing metabolite concentrations at the endothelium during hypoxia.ResultsThe metabolic model assesses central-to-peripheral corneal swelling with different types of lenses, and oxygen Dks. Limbal metabolic support reduces edema from the periphery to approximately 1 mm away from the central cornea. Despite thicker lens designs, the peripheral cornea exhibits practically zero swelling due to limbal metabolic support.ConclusionsThe metabolic model accurately predicts central-to-peripheral corneal edema with various contact-lens designs, post-lens tear-film thicknesses, and lens oxygen Dk values. Despite the thicker periphery of most contact-lens designs, lactate and bicarbonate support from the limbus significantly reduces peripheral and mid-peripheral corneal edema, whereas oxygen has a lesser effect.Translational RelevanceBy utilizing metabolic kinetics, we provide a 2D computational tool to predict oxygenation safety across the entire cornea with various types and designs of contact lenses.

Corneal Endothelial Decompensation.

Endothelial decompensation can occur from a variety of insults to the endothelium that result in loss of stromal clarity. Direct insults to the endothelium commonly occur in inherited, inflammatory, traumatic, immunological, and infectious etiologies. These injuries may cause transient injury without decompensation, but repetitive injury or severe isolated injury can lead to permanent non-compensatory endothelial cell loss. Elevated intraocular pressure can induce stromal hydration, either primarily or secondarily. With partial and full thickness corneal transplants, chronic endothelial dysfunction can be treated surgically when medical therapy proves inadequate. Practitioners should be aware of the underlying causes for corneal endothelial injury.