Applications of SMILE-extracted lenticules in ophthalmology.

AIM: To review recent innovations, challenges, and applications of small incision lenticule extraction (SMILE) extracted lenticule for treating ocular disorders. METHODS: A literature review was performed in the PubMed database, which was last updated on 30 December 2021. There was no limit regarding language. The authors evaluated the reference lists of the collected papers to find any relevant research. RESULTS: Due to the simplicity and accuracy of modern femtosecond lasers and the extensive development of SMILE surgery, many healthy human corneal stromal lenticules were extracted during surgery, motivating some professionals to investigate the SMILE lenticule reusability in different ocular disorders. In addition, new approaches had been developed to preserve, modify, and bioengineer the corneal stroma, leading to the optimal use of discarded byproducts such as lenticules from SMILE surgery. The lenticules can be effectively re-implanted into the autologous or allogenic corneas of human subjects to treat refractive errors, corneal ectasia, and corneal perforation and serve as a patch graft for glaucoma drainage devices with better cosmetic outcomes. CONCLUSION: SMILE-extracted lenticules could be a viable alternative to human donor corneal tissue.

Cytomegalovirus keratitis in acute myeloblastic leukemia.

A 58-year-old woman presented with acute myeloblastic leukemia (AML) developed a bilateral dendritic epithelial keratitis without retinitis. The patient was initially treated with oral acyclovir with a possible diagnosis of herpes simplex virus (HSV) keratitis. Polymerase chain reaction (PCR) was performed on ocular discharge specimens collected by soft-tipped applicators reported as cytomegalovirus (CMV). Then, acyclovir was discontinued and bilateral CMV keratitis was treated with IV ganciclovir and her epithelial lesions gradually disappeared. The current case report confirms that CMV is capable of generating corneal epithelial engagement without retina involvement and demonstrated that CMV keratitis is an emergent problem of AML. Therefore, in any case with bilateral corneal herpes keratitis, the patient should be evaluated for immune system deficiency.

Buccal mucosal membrane graft for correction of cicatricial lower eyelid retraction.

BACKGROUND: To evaluate the outcomes of a surgical technique using buccal mucosal membrane graft for correction of cicatricial lower eyelid retraction. METHODS: Twelve patients with unilateral cicatricial lower eyelid retraction were enrolled in the study. All patients underwent a four-step surgical technique consisted of release of scars, midface lift, transfer of buccal mucosal membrane to posterior lamella as spacer graft, and canthal tightening. All patients were followed for at least 12 months. RESULTS: Mean preoperative Margin-to-Reflex-Distance 2 (MRD2) was 7.73 ± 1.10 mm, compared to mean postoperative MRD2 of 5.04 ± 0.49 mm (P < 0.0001). The mean improvement in retraction was 2.69 mm. Postoperative scleral show was present in only one case and no major complications were observed. CONCLUSION: The four-step procedure (scar release, midface lift, buccal mucosal graft and canthal tightening) was an effective procedure to correct cicatricial lower eyelid retractions with acceptable outcomes and a low morbidity rate.

Histopathology Study of Patients with Delayed Mustard Gas Keratopathy 30 Years After Exposure.

Background & Objective: Delayed mustard gas keratopathy (DMGK) is the main chronic outcome in eye-chemical injured patients. The aim of this study was the histopathological evaluation of mustard-exposed cornea after more than 30 years. Methods: Fourteen corneas after Lamellar keratoplasty were evaluated in this study. Corneal tissues were prepared by histologic methods and stained by H&E. Results: The main histopathological findings in these cases were the presence of severe stromal edema and corneal scar. In the sections with visible superficial epithelium, subepithelial bullae formation was observed. Focal or diffuse disruption of Bowman's membrane and replacement with fibrosis were also seen. There was no evidence of stromal vascularization and inflammation in all specimens. Conclusion: After more than 30 years, an extensive corneal scar is seen in sulfur mustard exposed patients. Scar tissue without vascularization and fibroblastic proliferation is the main finding in the sulfur mustard exposed cornea. This pathology result is different from other scars. No evidence of inflammation or immune cell infiltration should be considered in managing DMGK.

Tear proteomics analysis of patient suffered from delayed mustard gas keratopathy.

Understanding the molecular and cellular mechanisms involved in the pathogenesis of ocular injured induced by mustard gas can help better identify complications and discover appropriate therapies. This study aimed to analyze the proteomics of tears of chemical warfare victims with mustard gas ocular injuries and compare it with healthy individuals. In this case-control research, 10 mustard gas victims with long-term ocular difficulties (Chronic) were included in the patient group, while 10 healthy persons who were age and sex matched to the patients were included in the control group. Schirmer strips were used to collect the tears of the participants. Proteomics experiments were performed using the high-efficiency TMT10X method to evaluate the tear protein profile, and statistical bioinformatics methods were used to identify the differently expressed proteins. 24 proteins had different expressions between the two groups. Among these 24 proteins, 8 proteins had increased expression in veterans' tears, while the remaining 16 proteins had decreased expression. Reactome pathways were used to look at proteins with various expressions, and 13 proteins were found to be engaged in the immune system, 9 of which were effective in the innate immune system, and 5 proteins were effective in the complement cascade. Ocular mustard gas exposure may cause a compromised immune system on the eye's surface, exposing the cornea to external and endogenous infections, and eventually causing corneal opacity and reduced vision.

The role of saffron in improvement of ocular surface disease in a mouse model of Lacrimal Gland Excision-induced dry eye disease.

One of the most prevalent eye disorders is dry eye disease (DED), described by ocular dryness due to the tear insufficiency. Prolonged dry eye causes damage and ulcer to the surface of the cornea. The core of the DED mechanism is inflammation which is a biological response of the body to pathogens. Several studies have indicated that saffron has many beneficial biological effects, such as anti-inflammatory and free radical scavenging. This research aims to examine possible positive impact of saffron in the mice model of DED. The animals were divided into 4 groups. Induction of DED was done by right Lacrimal Gland Excision (LGE). Treatment was done by intraperitoneal (i.p.) injection of saffron (1 mg/kg/day, for 28 days after induction of DED) in the SAF group, betamethasone (the BET group) (i.p., 1 mg/kg/day, for 28 days after induction of DED), the LGE group (received normal saline i.p. for 28 days after induction of DED) and the sham group (no induction of DED). Ophthalmological assay with fluorescein staining on the 0, 14 and, 28 days, histopathological analysis (H & E assay) on the last day and, pro-inflammatory cytokine assays of eyes were done. Saffron and betamethasone reduced the fluorescein score of the eyes (P < 0.0001) and improved the ocular surface disease in H & E assay as well as reduced the eye levels of TNF-α (P < 0.01), IL-1ß (P < 0.0001) and, IL-6 (P < 0.001) compared to those of the LGE group. The current study indicated that treatment with saffron has a beneficial effect on LGE (Lacrimal gland excision)-induced DED in mice via its anti-inflammatory properties.

Detection of COVID-19 in tears of ICU-admitted patients with SARS-CoV-2 infection.

PURPOSE: Upon the outbreak of 2019, novel coronavirus (COVID-19) pandemic confirmed the cases surpassed 20 million. Despite a few reports identified the association of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with ocular manifestations, it may assess the ocular symptoms of patients with the COVID-19 by ophthalmologists facilitate the diagnosis and prevent transmission. METHODS: A total of 60 patients with the COVID-19 admitted to Baghiatallah hospital from March 2020 to May 2020 were retrospectively reviewed and analyzed for the ocular manifestations, blood tests, and reverse transcriptase-polymerase chain reaction (RT-PCR) for SARS-CoV-2 using nasopharyngeal and conjunctival swabs. RESULTS: Among 60 included patients with clinically confirmed COVID-19, the median age 58.36 years (IQR: 30-88 years), 27 (45%) were male. Furthermore, 29 (48%) and 5 (8%) patients yielded positive for SARS-CoV-2 on RT-PCR from nasopharyngeal swabs and conjunctival specimens, respectively. Among 60 patients, 10 (16%) and 3 (5%), respectively, had the ocular manifestations and positive results for SARS-CoV-2 on RT-PCR from conjunctival and nasopharyngeal swabs. CONCLUSION: Although the positive rate of tear RT-PCR rate is not noticeable as nasopharyngeal swabs yet, COVID-19 transmission through the eyes is biologically plausible.

Comparison of the effect of removing bandage contact lens on the days 3 and 5 following photorefractive keratectomy.

AIM: To compare the outcomes of removing bandage contact lens (BCL) on days 3 and 5 after photorefractive keratectomy (PRK). METHODS: One hundred patients who underwent PRK (a total of 200 eyes) were enrolled in the present study. The subjects were assigned to two groups. Group 1 consisted of the right eyes of subjects and bandage contact lenses removal were on the 3rd day; Group 2 consisted of the fellow eyes of same subjects and removed bandage contact lenses on the 5th day after PRK. Then, data obtained from both groups were compared. To evaluate complications, the subjects underwent a slit-lamp examination in all visits. RESULTS: Filamentary keratitis was observed in one eye in both groups. The frequency of haze was higher in group 1; however, it was not significant between the two groups. Using mixed model analysis, significant differences were observed in the rate of complications as well as pain and eye discomfort scores between the groups (P < 0.05). No major complication was reported. CONCLUSION: Majority of post-PRK corneal epithelial defect is healed on day 3. However, keeping BCL for 5 days postoperatively instead of the three days produces a slightly lower rate of total complication.

COVID-19: Preliminary Clinical Guidelines for Ophthalmology Practices.

The zoonotic Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and its resultant human coronavirus disease (COVID-19) recently appeared as a global health threat that can cause severe respiratory infection and terminal respiratory distress. By the first week of April, more than 1.3 million people had been globally infected and more than 70,000 had lost their lives to this contagious virus. Clinical manifestations occur shortly after exposure, or a few days later. There is controversy regarding the transmission of the virus through the tear and conjunctiva; however, there are reports that the ocular surface might be a potential target for COVID-19. The ease of transmission of this virus at close proximity presents a risk to eyecare workers. Several recommendations have been issued by local and national organizations to address the issue of safe ophthalmic practice during the ongoing COVID-19 pandemic. These guidelines have numerous similarities; however, subtle differences exist. The purpose of this paper was to discuss measures, with a specific focus on standard precautions, to prevent further dissemination of COVID-19 at Eye Clinics. We have proposed procedures to triage suspected cases of COVID-19, considering emergency conditions.

Choroidal Thickness and Hemoglobin A1c Levels in Patients with Type 2 Diabetes Mellitus.

PURPOSE: The aim of this study was to assess the correlation of hemoglobin A1c (HbA1c) levels with choroidal thickness in patients with type 2 diabetes mellitus (DM) using spectral domain optical coherence tomography (SD-OCT). METHODS: In this prospective case series, 180 eyes from 90 patients with type 2 DM were classified into three study groups based on HbA1c values: group 1 included patients with good glycemic control (HbA1c ≤ 7%), group 2 included patients with moderate glycemic control (HbA1c between 7% and 8%), and group 3 included patients with poor glycemic control (HbA1c ≥ 8%). Additionally, 50 eyes from 25 non-diabetic subjects were enrolled to group 4 as a control group. Sub-foveal, nasal, and temporal choroidal thickness were measured and compared. RESULTS: Mean central, nasal, and temporal choroidal thicknesses in diabetic patients (247.80, 238.63, and 239.30 µ m) were significantly less than non-diabetic healthy subjects (277.56, 262.92, and 266.32 µ m). Additionally, mean central, nasal, and temporal choroidal thickness values in group 4 (277.56, 262.92, and 266.32 µ m) were significantly greater than the corresponding values in group 2 (248.34, 237.55, and 236.45 µ m) and group 3 (239.81, 234.62, and 233.94 µ m), but was not significantly different from corresponding values in group 1 (259.46, 246.12, and 251.00 µ m). CONCLUSION: HbA1c values have a significant correlation with choroidal thickness in diabetic patients, and better glycemic control with HbA1c ≤ 7% may prevent choroidal thinning.

Use of low-vault posterior chamber collagen copolymer phakic intraocular lenses for the correction of myopia: a 3-year follow-up.

BACKGROUND: Phakic intraocular lens (pIOL) models have indicated an association between cataract formation and inadequate vaulting. In this study, the efficacy and safety of low-vault posterior chamber pIOLs in the correction of myopia were examined over 3 years. METHODS: From 316 patients undergoing surgery, 14 eyes with a low vault (≤ 150 µm) were examined from 14 patients. After implanting the Visian Implantable Collamer pIOL for the correction of myopia (moderate and high), the pIOL vault, endothelial cell loss, uncorrected distance visual acuity (UDVA), corrected DVA (CDVA), and detrimental events were examined over 3 years. RESULTS: Based on the findings, the mean spherical equivalent reduced from - 8.15 ± 3.29 before surgery to - 1.02 ± 0.75 diopters 3 years after the surgery. In terms of visual outcomes, the mean UDVA (Log MAR) significantly increased from 0.95 ± 037 to 0.27 ± 0.28, and the mean CDVA also increased from 0.99 ± 0.11 to 0.06 ± 0.08 (P < 0.05). The mean indices of safety and efficacy were respectively 1.075 and 0.748. The eyes lost not more than two visual acuity lines. Based on the findings, 82% achieved 0.80 or better CDVA, while the total endothelial cell loss was 7.96% during 3 years. Overall, vision-threatening conditions were not reported. CONCLUSION: The introduced pIOL can be considered a safe and efficient method for myopia at moderate to high levels.

Choroidal neovascularization following photorefractive keratectomy.

PURPOSE: To describe a case of choroidal neovascularization (CNV) following photorefractive keratectomy (PRK) to correct myopia. METHODS: We performed PRK in both eyes of a 20-year-old girl to correct myopia. Refractive error was -4.75 -2.25 × 5 in the right eye and -5.00 -1.25 × 180 in the left eye. Metamorphopsia was noticed by the patient in the right eye one month after the surgical procedure. The patient was referred 3 months later when visual loss happened. RESULTS: Fluorescein angiography and Optical Coherence Tomography (OCT) were performed which were compatible with CNV. After three monthly intravitreal bevacizumab injections, sub-retinal hemorrhage and intraretinal fluid resolved, but subretinal scar remained without any visual acuity improvement. CONCLUSIONS: It seems that CNV may occur after PRK in myopic eyes. Also, refractive surgeons should consider CNV development in cases with visual compliant or metamorphopsia following PRK.

Visual Outcomes of Successful versus Failed Big-Bubble Deep Anterior Lamellar Keratoplasty for Keratoconus.

PURPOSE: To compare the visual outcomes of deep anterior lamellar keratoplasty (DALK) for keratoconus with and without successful big-bubble formation. METHODS: In this retrospective comparative study, a total of 289 consecutive eyes from 257 patients underwent DALK using the big-bubble technique. In cases where the big bubble could not be accomplished, manual stromal dissection down to Descemeton membrane (DM) was performed using a crescent knife. Visual acuity and refractive outcomes were compared between the bare DM group (Group 1) and manual dissection group (Group 2). RESULTS: A bare DM was successfully achieved in 229 (79.2%) eyes and manual dissection was performed in 60 (20.8%) eyes. The study groups were comparable in terms of age (P = 0.79), preoperative best-spectacle corrected visual acuity (BSCVA) (P = 0.15), and follow-up duration (P = 0.73). Postoperative BSCVA was significantly better in Group 1 than in Group 2 throughout follow-up (P < 0.05). In Group 2, BSCVA was significantly lower in eyes with advanced keratoconus as compared to those with moderate keratoconus (P = 0.007). At final follow-up, BSCVA ≤ 0.30 logarithm of minimum angle of resolution (logMAR) was achieved in 82.1% of eyes in Group 1 versus 54.5% of eyes in Group 2 (P < 0.001). Groups 1 and 2 were comparable in terms of postoperative spherical equivalent refractive error (P = 0.61) and keratometric astigmatism (P = 0.39). CONCLUSION: Retention of the posterior corneal stroma which occurs with manual dissection during failed big bubble formation in DALK is associated with lower visual acuity as compared to achieving a bare DM.

Factors influencing big-bubble formation during deep anterior lamellar keratoplasty in keratoconus.

PURPOSE: To investigate recipient and operative factors that can influence the rate of achieving a bare Descemet's membrane (DM) during deep anterior lamellar keratoplasty (DALK) for keratoconus. MATERIALS: In this retrospective comparative study, a total of 290 (153 right) consecutive eyes from 257 (179 male) keratoconus-affected patients who underwent DALK with the big-bubble technique were enrolled. Univariate analyses and multiple logistic regressions were used to investigate factors including patient age and sex, family history of keratoconus, history of contact lens wear or vernal keratoconjunctivitis, the presence of Vogt's striae or superficial stromal opacities, keratometric readings, corneal diameter, central and peripheral corneal thickness, anterior chamber depth, vitreous length, and trephination size, which could predict achievement of a bare DM. RESULTS: The surgery was completed as a DALK in 289 of 290 eyes, and a bare DM was successfully achieved in 229 (79.2%) eyes. The recipient sex and trephination size significantly influenced the success rate of big-bubble formation. Females had decreased odds of achieving a bare DM by 0.44 times (p=0.02). For each 0.1 mm increase in the trephination size, the odds of a successful big-bubble formation increased by 1.36 times (p=0.03). Other investigated factors did not significantly influence the rate of achieving a bare DM. CONCLUSIONS: The rate of successful big-bubble formation was 79.2% in keratoconus. Among the different factors, recipient sex and trephination size significantly influenced this rate. Females had a lower probability of big-bubble formation, and a large trephination size was associated with an increase in the probability of achieving a bare DM.

Big-bubble deep anterior lamellar keratoplasty using central vs peripheral air injection: a clinical trial.

PURPOSE: To compare 2 sites of air injection to achieve Descemet membrane (DM) detachment in big-bubble deep anterior lamellar keratoplasty (DALK). METHODS: In this prospective, randomized study, 48 eyes of 48 keratoconus-affected patients who underwent DALK by cornea fellows were enrolled. Each patient was randomly assigned into one of 2 groups. After trephination to approximately 80% of the corneal thickness, a 27-G needle was inserted into the stroma from the trephination site. The needle was moved radially inside the trephination site and advanced to the central or paracentral cornea in group 1. In group 2, the needle was inserted into the deep stroma from the trephination site and advanced into the peripheral cornea to approximately 1.5 mm anterior to the limbus. Air was gently injected into the deep stroma until a big bubble was formed. The rates of DM separation and complications were compared between the 2 groups. RESULTS: Big-bubble formation was successful in 79.2% of the eyes in the study group. A bare DM was achieved by central injection in 68.0% of group 1 and by peripheral injection in 69.6% of group 2 (p = 0.68). This rate was increased to 80.0% and 78.3% in groups 1 and 2, respectively, after the injection site was shifted when injections failed. The study groups were comparable in terms of complications including DM perforation and bubble bursting. CONCLUSIONS: Both injection sites were equivalent in their rates of big-bubble formation and complications. Less experienced surgeons are advised to initially inject air outside the trephination.