Corneal Protection Research Articles

A Prospective, Randomized, Controlled Clinical Investigation Comparing the Efficacy and Safety of Sodium Hyaluronate-Based Ophthalmical Viscosurgical Devices FIDIAL PLUS and IAL®-F in Cataract Surgery.

Purpose: To protect the corneal endothelium, various ophthalmical viscoelastic devices (OVDs) are used during cataract surgery. In this study, we compared two sodium hyaluronate-based OVD, the bacteria-derived FIDIAL PLUS OVD (test) with the animal-derived IAL®-F OVD (reference) during the surgical procedure. Methods: Fifty patients with bilateral cataract participated in the study: 50 eyes randomly received FIDIAL PLUS and 50 eyes received IAL®-F (ratio 1:1). Noninferior efficacy of FIDIAL PLUS compared with reference OVD (first objective) was evaluated using a paired t-test comparing the mean percent loss of corneal endothelial cells (CECs) with FIDIAL PLUS against the mean percent loss with IAL®-F. Corneal endothelial protection during cataract surgery with FIDIAL PLUS without significant (≥30 mmHg) postoperative intraocular pressure (IOP) increase (main secondary objective) was assessed using a repeated measures logistic model comparing the incidence of significant postoperative IOP elevation between the two groups. Safety, tolerability, and efficacy were also evaluated by assessing secondary endpoints before and after surgery. Results: FIDIAL PLUS showed a statistically noninferior efficacy compared with IAL®-F; there was no significant increase in IOP in either group or different trends of the secondary endpoints were observed between the OVD groups. The safety profile was similar in both OVD groups and no adverse device effects were reported. Conclusions: This study demonstrates the equivalent efficacy, tolerability, and safety of the bacteria-derived FIDIAL PLUS compared with the animal-derived IAL®-F, confirming the clinical value of this product.

Retention time of different ophthalmic viscosurgical devices during phacoemulsification in rabbit ocular model: A comparative analysis.

To compare retention times of various ophthalmic viscosurgical devices (OVDs) and soft-shell combinations. Experimental study. Eighteen rabbit eyes were divided into six groups of three eyes, based on OVDs tested. A: Endocoat, B: HealonPro, C: Viscoat, D: Provisc, E: Endocoat and HealonPro and F: Viscoat and Provisc. OVDs were stained with 10% fluorescein dye before being injected into the anterior chamber. Phacoemulsification, using fixed parameters, was performed. If OVD persisted after 60 s, a standardised irrigation and aspiration technique replaced phacoemulsification. The time until central and complete clearance of the OVD were video-recorded and measured. Mean central retention times (CRT) were found to be: HealonPro-5.33 ± 2.56 s, Provisc-3.33 ± 1.11 s, Endocoat-75.0 ± 3.26 s, Viscoat-62.33 ± 5.19 s, combining HealonPro with Endocoat-22.67 ± 4.75 s and Provisc with Viscoat-11.0 ± 0.82 s. The mean total retention time (TRT) was: Endocoat-80.0 ± 8.17 s, Viscoat-81.67 ± 2.09 s, HealonPro with Endocoat-81.33 ± 3.35 s, and Provisc with Viscoat-71.0 ± 2.94 s. For HealonPro and Provisc, CRT and TRT remained identical across all trials. Retention times varied, with cohesive OVDs exhibiting shorter durations than dispersive OVDs. Among dispersive OVDs, TRTs were comparable; however, Endocoat displayed an extended CRT. In soft shell trials, the combination of HealonPro and Endocoat exhibited prolonged CRT and TRT, suggesting enhanced corneal protection.

Calcitonin gene‐related peptide and persistent corneal pain: A trigeminal nerve sensitization perspective

AbstractPersistent corneal pain (PCP) has excellent research prospects, especially the central sensitization mechanism of the trigeminal nerve, which is involved in migraine, corneal pain, and trigeminal neuralgia. The cornea has dense sensory innervation, and repeated corneal neuropathic pain has been associated with trigeminal nerve central sensitization, which is induced in PCP. The calcitonin gene‐related peptide (CGRP) is involved in corneal pain conduction, injury protection, and immune homeostasis. A high CGRP level maintains corneal pain perception and protects corneal epithelial cells. However, a persistently high CGRP level causes hypersensitivity of the corneal and trigeminal nerves, resulting in PCP. CGRP‐related drugs can effectively improve trigeminal nerve sensitization and relieve central sensitization‐related pain (PCP, migraine, and trigeminal neuralgia). Exploring the role of CGRP in PCP's pain sensitization mechanism is vital in the pain perception field, with the potential to improve the quality of life of patients with PCP and strengthen the understanding of CGRP's dual role in corneal pain.

Efficacy of the Buried Temporary Suture Tarsorrhaphy: A Novel Technique.

To describe a buried variation of the temporary suture tarsorrhaphy and determine its efficacy period. This retrospective case review includes 11 patients needing corneal protection. Six patients had lagophthalmos from facial nerve palsy, 4 had cicatricial ectropion, and 1 had neurotrophic keratopathy. A total of 14 buried temporary suture tarsorrhaphies (BTSTs) were placed. The duration of the BTST was the main outcome. The corneal status before and throughout the BTST was monitored. The eyelids were examined for any undesired changes from the BTST. The mean duration of the BTST was 97.5 days, with a maximum of 273 days. Aside from one spontaneous dehiscence 5 days after placement, all BTSTs held until intentional removal. Five BTSTs were removed for a more definitive surgical procedure, 6 were removed after resolution of the initial indication, and 2 are still in place as the patient awaits surgery. All cases of keratopathy improved after BTST placement. There were no complications and no undesired eyelid changes. The BTST is a simple, fast, safe, and effective procedure that can be performed in the clinic or inpatient to immediately improve ocular surface coverage. As a minimally invasive procedure that can easily last several months, the BTST is an excellent option for patients who require more intense intervention than medical management alone. It can also securely bridge patients to a permanent solution such as lateral canthal resuspension.

Long-Term Real-World Outcomes of Corneal Changes in Proliferative Diabetic Retinopathy: Panretinal Photocoagulation vs. Intravitreal Conbercept

PurposeTo compare long-term real-world outcomes of corneal thickness (CT) alterations in proliferative diabetic retinopathy (PDR) patients treated with panretinal photocoagulation (PRP) and intravitreal conbercept (IVC). MethodsThis retrospective study included 69 eyes of 69 patients with PDR (42 PRP and 27 IVC). Full corneal thickness (FCT), corneal epithelial thickness (CET) and corneal stromal thickness (CST) measured by anterior segment optical coherence tomography at baseline were compared between groups. These CT changes at last follow-up from baseline were also compared between groups and within each group. ResultsDuring a mean follow-up of more than two years, the IVC group demonstrated a significantly increased corneal thickness from baseline compared to the PRP group in some areas (PRP vs. IVC: FCT 0-2 mm: -0.59 ± 9.31 vs. 5.59 ± 9.23 μm, p = 0.009; CST 0-2 mm: -2.05 ± 8.79 vs. 3.48 ± 7.52 μm, p = 0.015; CST 2-5 mm: -1.78 ± 13.27 vs. 5.68 ± 14.53 μm, p = 0.046). In within-group comparisons, a significantly increased FCT from baseline was found in the 0-2 mm area in the IVC group (p = 0.004), but no significant change was observed in the PRP group (p = 0.691). For CET changes, a significantly increased CT was observed in the 0-2 mm, 2-5 mm and 5-7 mm areas in both groups respectively (all p < 0.05). Regarding CST, an increased CT was found in the 0-2 mm area in the IVC group (p = 0.037), while a decreased trend was observed in 0-2 mm and 2-5 mm areas in the PRP group (all p > 0.05). ConclusionWhen using PRP or IVC in the long-term management of PDR, CT changes should be considered. This may provide evidence for corneal protection during PDR treatment.

Mitigation of pesticide-mediated ocular toxicity via nanotechnology-based contact lenses: a review.

Thexenobioticstress exerted by pesticides leads to the deterioration of human and animal health including ocular health. Acute or prolonged exposure to these agricultural toxicants has been implicated in a number of pathological conditions of the eye such as irritation, epiphora or hyper-lacrimation, abrasions on the ocular surface, and decreased visual acuity. The issue is compounded by the fact that tissues of the eye absorb pesticides faster than other organs of the body and are more susceptible to damage as well. However, there is alacunain our knowledge regarding the ways by which pesticide exposure-mediated ocular insult might be counteracted. Topical instillation of drugs known to combat the pesticide induced toxicity has been explored to mitigate the detrimental impact of pesticide exposure. However, topical eye drop solutions exhibit very low bioavailability and limited drug residence duration in the tear film decreasing their efficacy. Contact lenses have been explored in this respect to increase bioavailability of ocular drugs, while nanoparticles have lately been utilized to increase drug bioavailability and increase drug residence duration in different tissues. The current review focuses on drug delivery and futuristic aspects of corneal protection from ocular toxicity using contact lenses.

Subconjunctival administration of mesenchymal stem cells alleviates ocular inflammation in a murine model of corneal alkali burn.

Corneal alkali burns cause extensive damage not only on the cornea but also into the intraocular tissues. As an anti-inflammatory therapy, subconjunctival administration of mesenchymal stem cells (MSCs) for corneal protection after corneal alkali burn has been explored. Little evidence demonstrates the potential of subconjunctival MSCs delivery in protecting the post-burn intraocular tissues. This study aimed to evaluate the therapeutic efficacy of subconjunctival injection of human placental (hP)-MSCs in protecting against ocular destruction after the burn. hP-MSCs were subconjunctivally administered to C57/BL mice after corneal alkali burn. Western blot of iNOS and CD206 was performed to determine the M1, M2 macrophage infiltration in the cornea. Infiltration of inflammatory cells in the anterior uvea and retina were analyzed by flow cytometry. The TUNEL assay or Western blot of Bax and Bcl2 was used to evaluate the anti-apoptotic effects of MSCs. MSCs could effectively facilitate cornea repair by suppressing inflammatory cytokines IL-1β, MCP-1, and MMP9, and polarizing CD206 positive M2 macrophages. Anterior uveal and retinal inflammatory cytokines expression and inflammatory cells infiltration were inhibited in the MSC-treated group. Reduced TUNEL positive staining and Bax/Bcl2 ratio indicated the anti-apoptosis of MSCs. MSC-conditioned medium promoted human corneal epithelial cell proliferation and regulated LPS-stimulated inflammation in RAW 264.7 macrophages, confirming the trophic and immunoregulatory effects of MSCs. Our findings demonstrate that subconjunctival administration of MSCs exerted anti-inflammatory and anti-apoptotic effects in the cornea, anterior uvea, and retina after corneal alkali burn. This strategy may provide a new direction for preventing post-event complications after corneal alkali burn.

Basal cell carcinoma of the medial canthus: resection and reconstruction by glabellar flap

The inner canthus is the site of aggressive basal cell carcinomas. The management of these tumors requires knowledge of the basic principles of reconstruction in reconstructive surgery. Surgical resection with exhaustive control of the excision margins should be performed. Even when the tumor is small, the need for healthy margins often results in a moderate to a large palpebral defect that cannot be repaired with direct sutures. The goal of reconstruction is to achieve a mobile eyelid, good corneal protection, and a good aesthetic result with acceptable donor site sequelae. In this manuscript, we describe a case of basal cell carcinoma of the medial canthus that underwent resection followed by reconstruction with a glabellar flap.

Myeloid cells protect corneal nerves against sterile injury through negative-feedback regulation of TLR2–IL-6 axis

BackgroundMounting evidence suggests that the immune system plays detrimental or protective roles in nerve injury and repair.Main bodyHerein we report that both CD11bhiLy6Ghi and CD11bhiLy6ChiLy6Glo myeloid cells are required to protect corneal nerves against sterile corneal injury. Selective depletion of CD11bhiLy6Ghi or CD11bhiLy6ChiLy6Glo cells resulted in aggravation of corneal nerve loss, which correlated with IL-6 upregulation. IL-6 neutralization preserved corneal nerves while reducing myeloid cell recruitment. IL-6 replenishment exacerbated corneal nerve damage while recruiting more myeloid cells. In mice lacking Toll-like receptor 2 (TLR2), the levels of IL-6 and myeloid cells were decreased and corneal nerve loss attenuated, as compared to wild-type and TLR4 knockout mice. Corneal stromal fibroblasts expressed TLR2 and produced IL-6 in response to TLR2 stimulation.ConclusionCollectively, our data suggest that CD11bhiLy6Ghi and CD11bhiLy6ChiLy6Glo myeloid cells confer corneal nerve protection under sterile injury by creating a negative-feedback loop to suppress the upstream TLR2–IL-6 axis that drives corneal nerve loss.

Corneal integrity in ahmed valve implantation: pars plana vs ciliary sulcus vs anterior chamber

Complex and refractory glaucoma cases, non-responsive to maximal management, require surgical intervention. The Ahmed Valve, a Glaucoma Drainage Device, is widely used in these scenarios. It may be implanted into the anterior chamber, ciliary sulcus and pars plana. However, there is no general consensus in the literature on which location is best when corneal protection is considered. This paper aimed to review all these studies, including ours, to determine which may be best, while still not compromising on valve efficacy in intraocular pressure reduction.

Scleral Lenses Improve Ptosis in Patients with Concurrent Ocular Surface Disease: A Case Series

Scleral lenses are a well-established contact lens option for patients with corneal irregularity and/or ocular surface disease. They provide a unique design by vaulting over the limbus of the cornea and rest on the conjunctiva with no blood vessel compression. Scleral lenses have an additional benefit of improving eyelid ptosis; however, this use has been minimally reported in the literature. This use has probably not been reported as frequently because the primary goals of fitting these lenses are most often improvement in vision, protection/support of the ocular surface, and/or improvement in comfort. It is hypothesized that the increased bulk of scleral lenses contribute to an increase in lid aperture size and the marginal reflex distance. Scleral lenses offer a non-surgical and non-pharmacological option for ptosis improvement, particularly in cases of mild ptosis and/or when the patient is not a good surgical candidate. They are a good option for improving ptosis in patients with concurrent ocular surface disease as they offer corneal protection as the eyelid retracts. They serve as an appropriate option for patients who are susceptible or experience adverse side effects of topical ophthalmic solutions for ptosis including dry eye, pain, and headache.1 The following case series highlights several cases in which scleral lenses improved ptosis measurements following scleral lens fitting. CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Click here to Enroll (https://www.crojournal.com/scleral-lenses-improve-ptosis-in-patients-with-concurrent-ocular-surface-disease-a-case-series). Please check COPE course expiry date prior to enrollment. The COPE course test must be taken before the course expiry date.

Corneal endothelium protection provided by ophthalmic viscosurgical devices during phacoemulsification: experimental study in rabbit eyes.

To compare the protection of the corneal endothelium provided by a cohesive and a dispersive ophthalmic viscosurgical device (OVD) against damage from torsional ultrasound and simulated lenticular debris during phacoemulsification. University setting, Salt Lake City, Utah. Experimental study. 15 New Zealand rabbits were included. After incision, each eye received cohesive or dispersive OVD (ProVisc or Viscoat). 10 1.0 mm beads were injected to simulate lenticular debris. The Intrepid Balanced tip (Centurion Ozil handpiece) was inserted into the anterior chamber, and 60% torsional ultrasound with 50 mL/min flow, 70 mm Hg intraocular pressure, and 600 mm Hg vacuum was applied (20 seconds). Cumulative dissipated energy (CDE) was noted. After euthanasia and enucleation, corneas were removed, stained with trypan blue/alizarin red, and photographed (5 ×400 magnification photos and 1 overview photograph from each cornea). ImageJ was used to evaluate cell damage and loss. CDE was 4.70 ± 0.26 and 4.64 ± 0.10 in the cohesive and dispersive OVD groups, respectively ( P = .8647). The analysis of the ×400 photographs showed that the percentage of intact cells was statistically higher in the dispersive OVD group ( P = .0002), whereas the percentages of damaged and lost cells were statistically higher in the cohesive OVD group ( P = .0002 and .0059, respectively). Overview photographs revealed the presence of residual OVD on the endothelium, especially in the dispersive group. In this experimental study using a rabbit model, the corneal endothelium protection provided by the dispersive OVD was superior to that provided by the cohesive OVD.

Corneal endothelial protection during manual small-incision cataract surgery: A narrative review.

Cataract causes bilateral blindness in 20 million people globally, the vast majority of whom live in developing countries. Manual small-incision cataract surgery (MSICS) has emerged as an efficient and economical alternative to phacoemulsification, giving comparable results in terms of final visual gain. One of the important determinants of postoperative visual gain is the status of the corneal endothelium. Multiple factors such as corneal distortion, irrigation solution turbulence, mechanical trauma by instruments, nuclear fragments, intraocular lens contact, and free oxygen radicals, all have been implicated in causing corneal damage during cataract surgery. MSICS with posterior chamber intraocular lens implantation has been reported to cause an endothelial cell loss of 15.83%, which is comparable with other modes of cataract surgery like extracapsular cataract extraction and phacoemulsification. Thorough preoperative assessment of endothelial status and taking necessary steps for endothelial protection during surgery can decrease the endothelial cell loss and overall burden of pseudophakic bullous keratopathy. In addition to surgical techniques, the type of irrigating solutions, ocular viscoelastic devices, intracameral dyes, and drugs all affect the endothelial cell status. This review presents a summary of available literature on the protection of endothelial cells during different steps of MSICS. This is especially relevant for developing countries where large-scale MSICS cataract surgeries are performed to decrease the cataract blindness burden.

‘Are dynamic procedures superior to static in treating the paralytic eyelid in facial paralysis?’

Facial nerve weakness can cause deficient eye closure with reduced corneal protection. Surgical remedies can be static to oppose the levator muscle (lid loading) or dynamic procedures, which act to increase the strength of closure. This retrospective cohort study compares these groups. The hypothesis is that dynamic reconstruction has advantages over static techniques in terms of eye closure, symptomatic improvement, blink restoration, and complication rate. Two cohorts were compared: those treated with a gold weight insertion into the upper eyelid and those who had received dynamic reconstruction. These included temporalis transfer; cross face nerve grafting alone (CFNG) and CFNG followed by free tissue transfer. Assessments included standard photography and video; measurement of eyelid excursion including residual gap and if full eye closure was possible. The presence of the blink reflex and symptoms of dry eye was assessed. Overall improvement in eye closure was similar with the gold weight compared to dynamic procedures (5.1mm vs 5.3mm). Dynamic procedures however gave improved results in terms of symptom relief and restoration of blink. They also had fewer complications and revision rates overall. The study confirms the hypothesis that dynamic reconstructions of the paralysed eyelid confer advantages compared to simple lid loading techniques. Improvements in lid excursion are similar, but symptom improvement and blink restoration are significantly better. A decision regarding eyelid reanimation should be made early in the patient's journey of facial reanimation to allow for accurate planning and placement of nerve grafts at an early stage.

Evaluation of the corneal morphologic and topographic alterations in patients with Bell’s palsy

Purpose: To evaluate the effects of ocular surface changes that may develop due to Bell’s palsy (BP) on dry eye parameters, corneal densitometry values, and aberrations in patients with unilateral BP and compare them with sound eyes.&#x0D; Materials and Methods: A total of 33 eyes of 33 patients diagnosed with unilateral BP and 33 sound fellow eyes of the patients were enrolled in this study. A complete ophthalmologic examination including best-corrected visual acuity (BCVA), intraocular pressure measurement, slit-lamp biomicroscopy to observe superficial punctate keratopathy (SPK), tear break-up time (TBUT) test, and detailed fundoscopic examination was performed for all patients. The corneal topographic, densitometric, and aberrometric measurements were performed using the Pentacam Scheimpflug imaging system.&#x0D; Results: The mean age of 33 patients was 54.9±14.7 years of whom 19 (57.6%) were female; 14 (42.4%) were male. According to the House-Brackmann scale, the majority of the patients had grade II facial nerve palsy. The BCVA in the affected eye was lower and 0.74±0.23 compared to 0.87±0.21 in sound eyes (p=0.029). The mean TBUT was lower and 6.0±4.7 in eyes affected by BP compared to 8.7±4.0 in sound eyes (p=0.014). The SPK was present in 23 (69.7%) patients. The comparison of the corneal densitometry values revealed that the densitometry measurements in anterior concentric zones were slightly higher in affected eyes. Corneal aberrometric values were also slightly higher in affected eyes. No significant difference was observed between affected and sound eyes in terms of corneal keratometric, densitometric, and aberrometric values (p&gt;0.05, for all).&#x0D; Conclusions: Corneal exposure leading to visual complications, and lowering of the tear production may lead to dry eye in BP patients. The examination of the ocular surface to observe the ocular findings of BP is essential. The main priority of the ophthalmologist is to ensure adequate corneal protection to prevent undesired ocular outcomes.

A prospective, masked, randomized, controlled superiority study comparing the incidence of corneal injury following general anesthesia in dogs with two methods of corneal protection.

ObjectiveTo compare the incidence of corneal injury during general anesthesia (GA) and the immediate post‐operative period in eyes protected with topical ocular lubricant alone with eyes protected with topical lubricant followed by complete eyelid closure using tape.Animals StudiedOne hundred client‐owned dogs (200 eyes) undergoing GA for MRI scan.MethodsPatients had ocular lubricant applied to both eyes upon induction of anesthesia. One eye was taped closed immediately after induction for the duration of anesthesia using Strappal® tape (BSN medical™; treatment group), and the other eye was not taped (control group). Eyes were randomly allocated to a treatment group. Ophthalmic examination was performed before and after anesthesia; the examiner was masked to eye treatment groups. Corneal injury was defined as corneal ulceration or corneal erosion. A McNemar's test was used to compare the incidence of corneal injury between groups. A paired‐samples t‐test was used to compare Schirmer‐1 tear test (STT‐1) readings between groups.ResultsSixteen eyes (8%) developed corneal erosion. No corneal ulceration occurred. There was no significant difference between incidence of corneal erosion between groups (p = .454). There was a significant decrease in STT‐1 readings following GA in both groups (p < .001), with no significant difference in STT‐1 between groups (p = .687). No adverse effects of taping the eye closed were observed.ConclusionTaping the eyes closed during GA had no additional benefit to the lubrication protocol used in this study.

Full-thickness lower eyelid defect reconstruction using a pedicle rotation temporal flap and Acellular Human Dermis Graft (Alloderm)

The aim of this research was to prospectively examine the combination of a pedicled temporal rotation flap with an acellular human dermal graft technique for intermediate-sized lower eyelid defect reconstruction. Pedicled temporal rotation flaps based on the orbicularis oculi muscle were used to reconstruct the anterior lamella of lower eyelid defects in six patients (five males and one female) while the posterior lamella was reconstructed using an acellular human dermis graft (Alloderm). Flap survival at 6 months was 100%. The functionality and cosmetic results of the technique were evaluated, and corneal protection was achieved. The texture and color of the reconstructed eyelid matched the surrounding skin, and neither pain nor corneal irritation was reported. The donor site scar healed well and was inconspicuous in all cases. Furthermore, no recurrence of malignancy was observed. The combination of a temporal rotational flap with an acellular human dermal graft is the key points. This technique could be ideal for the reconstruction of intermediate-sized full-thickness lower eyelid defects.

Pituitary Adenylate Cyclase-Activating Polypeptide Protects Corneal Epithelial Cells against UV-B-Induced Apoptosis via ROS/JNK Pathway Inhibition

PACAP is widely expressed throughout the body. It exerts a beneficial role in the eye, including the cornea. The corneal epithelium is regularly exposed to diverse types of insults, including ultraviolet B (UV-B) radiation. Previously, we showed the protective role played by PACAP in counteracting UV-B ray insults in human corneal endothelial cells; however, its involvement in corneal epithelium protection against ROS induced by UV-B radiation, and the underlying mechanisms, remain to be determined. Here, we demonstrated that the peptide treatment reduced UV-B-induced ROS generation by playing an anti-apoptotic role via JNK-signaling pathway inhibition. Overall, our results can provide guidance in the therapeutic use of PACAP for the treatment of epithelial corneal damage.

Синдром «сухого глаза» при кератоконусе: аспекты этиологии и медикаментозной коррекции

This paper reviews published data on the studies on keratoconus associated with dry eye disease (DED) presentations. Despite the lack of a direct correlation between DED and keratoconus, many studies have demonstrated that keratoconus is associated with DED in more than 80% of cases. The author describes major endogenous and exogenous (inflammatory, immune/allergic, mechanical, neuropathic) factors triggering the development and association of these conditions. Approaches to the medical treatment of disorders resulting from the association of these entities are discussed. The primary management strategy implies tear film and ocular surface protection with tear substitutes based on the sodium salt of hyaluronic acid. In the lack of the effect of tear substitutes or in rigid gas permeable contact lens wearers, gel-based dexpanthenol in high concentrations is recommended. This treatment significantly increases drug bioavailability and prolongs the ocular surface reparation. Scleral contact lenses ensuring intact corneal epithelium and high visual acuity in irregular astigmatism caused by keratoconus are also used for corneal protection and DED therapy. Keywords: keratoconus, keratectasia, dry eye disease, epitheliopathy, tear film. For citation: Averich V.V. Dry eye disease in keratoconus: etiology and medical treatment. Russian Journal of Clinical Ophthalmology. 2022;22(2):122–126 (in Russ.). DOI: 10.32364/2311-7729-2022-22-2-122-126.

Protecting the Corneal Endothelium during Cataract Surgery Using the Anterior Capsulorhexis Flap as a Corneal Protection Shield

Purpose: Classification and quantification of swirling lens fragments during phacoemulsification with or without using the capsulorhexis flap as an additional endothelial protective shield. Also, to determine the effects on endothelial cell count (ECC) and central corneal thickness (CCT) caused by fragments during cataract surgery. Methods: Patients with dense cataracts scheduled for surgery were randomized into study and control groups (2:1). In the study group, the anterior capsule ‘flap’ from the capsulorhexis was used as an endothelial protection shield during phacoemulsification. The control group underwent standard surgery. During surgery, intra-operative optical coherence tomography was performed to score swirling lens fragments that hit the corneal endothelium. CCT and ECC were measured at several time points before and after surgery. Results: In total, 176 fragments in 49 eyes of 49 patients came in contact with the corneal endothelium. The mean number of fragments was 2.8 in the study group and 4.8 in the control group. There was no statistically significant change of ECC between the groups. Mean CCT increased by 16.6 µm in the study group and by 42µm in the control group 1 day postoperatively. There was no significant difference between the groups regarding the increase in CCT. Conclusions: No significant benefit concerning ECC or CCT was found in the study group compared to the control group, meaning that we were not able to prove that using the capsulorhexis flap as a protection shield is a sufficient method of protecting the corneal endothelium.