Biosynthetic and functional defects in newly identified SLC4A11 mutants and absence of COL8A2 mutations in Fuchs endothelial corneal dystrophy.

Late-onset Fuchs endothelial corneal dystrophy (FECD) shows genetic heterogeneity. Identification of SLC4A11 as a candidate gene for congenital hereditary endothelial dystrophy with similar corneal endothelial defects as FECD and reduced mRNA expression of SLC4A11 in the endothelium of FECD cases suggested that this gene may also be involved in pathogenesis of FECD. Mutations in SLC4A11 give rise to SLC4A11 protein marked by retention in the endoplasmic reticulum as a result of mis-folding. We screened 45 sporadic late-onset, 4 early-onset FECD patients and an early-onset autosomal dominant FECD family. We identified three previously unreported missense mutations: c.719G>C (p.W240S), c.1519G>A (p.V507I) and c.1304C>T (p.T434I) in unrelated individuals. These SLC4A11 mutants, expressed in HEK293 cells, had defects in either their cell surface expression or functional activity (rate of osmotically driven water flux). SLC4A11 mutations contribute to 11% (5/45) of sporadic late-onset FECD in the cohort studied. COL8A2, which causes some cases of early-onset FECD, was also screened in this cohort. No mutations were identified in COL8A2, in neither the late-onset cohort nor the early-onset family, suggesting genetic heterogeneity in this FECD family.

Overview of sclerocornea.

Sclerocornea is a rare non-progressive, non-inflammatory usually bilateral congenital corneal opacity that can be associated with both ocular and systemic abnormalities. It could be inherited in 50% of cases. Ill-defined limbal architecture and vascularization in association with ocular comorbidities results in poor outcomes with corneal transplantation. This narrative review summarizes the current literature on etiology and clinical presentation in sclerocornea. With regards to keratoplasty, it focusses on key elements in decision making, highlights the role of investigations and discusses practical surgical pearls to enhance outcome of keratoplasty in these eyes.

Management of coexisting bilateral ocular surface disease in xeroderma pigmentosum - sequence and outcomes.

PURPOSE: To report a rare presentation of bilateral, coexisting ocular surface disease in a case of Xeroderma pigmentosum and its successful management. METHODS: Case report. RESULTS: A 21-year-old male with Xeroderma pigmentosum presented with bilateral ocular surface squamous neoplasia (OSSN) along with central guttae in the right eye and corneal decompensation of the left eye. Subsequently, the patient developed dry eyes and lid margin keratinization in both eyes followed by perforation in the left eye. Sequential procedures both medical and surgical, including excision of the tumour, corneal transplantation and mucous membrane grafting addressing each of these ocular surface issues resulted in a successful outcome. There was no recurrence of the tumour over 3 years. Corneal transplantation is preferably done after a minimum of 6 months following excision. Mucous membrane grafting performed for progressive lid margin keratinization resulted in surface stabilization. CONCLUSIONS: In Xeroderma Pigmentosum, multiple ocular surface features can rarely coexist and be bilateral. Periodic evaluation of the surface for tumours, progressive dry eyes and endothelial function is recommended as a part of routine evaluation in Xeroderma pigmentosum. Surface procedures should precede intraocular intervention. Sequential management can result in successful outcomes.

Role of polymerase chain reaction-based viral detection in pterygia.

Purpose: Pterygium is a fibrovascular disease that originates in the conjunctiva and commonly spreads to the corneal surface, thereby posing a threat to eyesight. Despite intensive research, the pathophysiology of this disease remains unclear. Recent research suggests that oncogenic viruses, such as human papillomavirus (HPV), cytomegalovirus, and Epstein-Barr virus (EBV), may play a role in pterygia development. Although there are questions concerning the function of oncogenic viruses in pterygium pathogenesis, existing research shows a lack of consensus on the subject, demonstrating the heterogeneity of pterygium pathophysiology. Therefore, we aimed to simultaneously detect the three common viral pathogens that have been reported in pterygium tissue obtained after excision. Methods: Thirty-five tissue specimens of pterygium from patients undergoing pterygium surgery (as cases) were analyzed for evidence of viral infection with multiplex polymerase chain reaction (PCR), and virus-specific real-time quantitative PCR was used for the samples that were detected positive by multiplex PCR. Results: Of the 35 patients, one sample was positive for EBV and two samples were positive for HPV. Further PCR-based DNA sequencing of the HPV PCR-positive product showed identity with HPV-16. Real-time quantitative PCR on samples that showed EBV or HPV positivity did not yield any detectable copy number. Conclusion: Our study results confirmed that PCR positivity could be due to transient flora, but it was not quantitatively significant to conclude as the causative factor of pterygium pathogenesis. However, additional studies with larger sample populations are warranted to fully determine the role of the virus in pterygium.

Stromal rejection in penetrating keratoplasty following COVID-19 vector vaccine (Covishield) - A case report and review of literature.

Endothelial rejection has been described following both m-RNA and vector-based vaccines for COVID-19. There is one case report of a stromal rejection described following influenza vaccination. We report a case of stromal rejection following vector-based COVID-19 vaccination, which might be the first case reported so far.

Voriconazole Induced Ocular Surface Dysplasia - Report of Two Cases.

PURPOSE: To report ocular surface dysplasia induced by voriconazole treatment in two patients with recalcitrant fungal keratitis. METHODS: Observational study. RESULTS: Case 1 - A 49 year old female who was a known case of fungal keratitis and treated with prolonged topical voriconazole therapy, underwent penetrating keratoplasty and the histopathological examination of corneal specimen showed multiple keratin pearls with dyskeratotic cells suggestive of squamous cell carcinoma.Case 2 - A 78-year-old man who was diagnosed as fungal keratitis in his left eye and treated with topical voriconazole 1% and itraconazole 1% for 6 months underwent therapeutic penetrating keratoplasty. Histopathology of the host corneal tissue showed squamous cells with irregular thickening with dyskeratotic cells and squamous eddies suggestive of voriconazole induced dysplasia. CONCLUSION: Prolonged topical voriconazole treatment in fungal keratitis can induce ocular surface dysplasia. Early diagnosis and treatment of the dysplastic changes can result in complete remission and prevent recurrence.

Anterior staphyloma repair following trauma and surgery - A retrospective review of techniques and outcomes over 25 years.

Purpose: To review surgical options, techniques, and outcomes of anterior staphyloma repair done following trauma and surgery. Methods: This was a retrospective case study of patients who underwent staphyloma repair with scleral or tibial periosteal patch grafts following trauma and surgery with a minimum follow-up of 3 months postoperatively. Preoperative risk factors, choice of graft materials, surgical details, and outcomes in terms of graft uptake and tectonic integrity were analyzed. Results: Seventeen eyes of 17 patients underwent successful staphyloma repair (scleral 15, tibial periosteal two). Mean follow-up was 47.1 months (3-159 months). Postoperative intraocular pressure rise noted in four eyes was controlled medically or surgically. Three patients underwent successful repeat patch grafting (graft melt one and recurrent ectasia two). Tectonic integrity of the eyeball was restored and maintained in all patients at the final follow-up. Conclusion: Comprehensive evaluation of the risk factors, control of ocular comorbid conditions, and early and meticulous surgery can optimize results.

Preliminary experience & rationale of primary allo Simple Limbal Epithelial Transplantation (SLET) following surgical excision of Ocular Surface Tumors.

AIM: To report the preliminary outcomes and elucidate the possible rationale of alloSLET for primary ocular surface reconstruction following excision of extensive ocular surface tumors. METHODS: Retrospective interventional case series with a minimum postoperative follow up of 1 year. AlloSLET was performed along with wide surgical excision and cryotherapy in 3 eyes. RESULTS: Of the 2 eyes with extensive OSSN and one with an extensive pigmented lesion, there was no occurrence of symblepharon in all 3 eyes. No features suggestive of LSCD was noted in 2 eyes. In the child with xeroderma pigmentosum and OSSN, early peripheral vascularization was noted at 1 year of follow up with reduced vision secondary to amblyopia. CONCLUSION: Primary alloSLET could be an alternative to primary autoSLET in eyes with extensive ocular surface tumors, commonly seen with ocular surface squamous neoplasia (OSSN) and pigmented lesions. This facilitates ocular surface reconstruction with reduced occurrence of symblepharon formation as well as limbal stem cell deficie4ncy (LSCD). It possibly, is the only option in eyes with OSSN with coexistent bilateral limbal insufficiency. It may obviate the need for autoSLET, primary or secondary in eyes with adequate residual limbus.

SLC4A11 mutations in Fuchs endothelial corneal dystrophy.

The endothelial (posterior) corneal dystrophies, which result from primary endothelial dysfunction, include Fuchs endothelial corneal dystrophy (FECD), posterior polymorphous corneal dystrophy (PPCD) and congenital hereditary endothelial dystrophy (CHED). Mutations in SLC4A11 gene have been recently identified in patients with recessive CHED (CHED2). In this study, we show that heterozygous mutations in the SLC4A11 gene also cause late-onset FECD. Four heterozygous mutations [three missense mutations (E399K, G709E and T754M) and one deletion mutation (c.99-100delTC)] absent in ethnically matched controls were identified in a screen of 89 FECD patients. Missense mutations involved amino acid residues showing high interspecies conservation, indicating that mutations at these sites would be deleterious. Accordingly, immunoblot analysis, biochemical assay of cell surface localization and confocal immunolocalization showed that missense proteins encoded by the mutants were defective in localization to the cell surface. Our data suggests that SLC4A11 haploinsufficiency and gradual accumulation of the aberrant misfolded protein may play a role in FECD pathology and that reduced levels of SLC4A11 influence the long-term viability of the neural crest derived corneal endothelial cells.

Subconjunctival bevacizumab and argon laser photocoagulation for preexisting neovascularization following deep lamellar anterior keratoplasty.

We report a rare case of deep anterior lamellar keratoplasty (DALK) neovascularization managed with combination of subconjunctival bevacizumab and argon laser photocoagulation. A 24 year old male underwent Deep anterior lamellar keratoplasty for corneal stromal opacity following presumed viral keratitis. Deep corneal neovascularization was observed postoperatively which was successfully managed using a combination of subconjunctival bevacizumab and argon laser photocoagulation within one week of DALK. The neovascularization resolved by 3 months and at 2 years follow up, patient maintained good visual acuity of 6/12 Snellen's without recurrence of vascularization. A combination of bevacizumab and argon laser may be an effective approach to manage neovascularisation in the immediate postoperative phase (Post DALK) and improve graft survival.

Clinical profile, risk factors and outcome of medical, surgical and adjunct interventions in patients with Pythiuminsidiosum keratitis.

PURPOSE: To report clinical profile and compare management options for Pythium keratitis. METHOD: Retrospective interventional study of 46 patients diagnosed as Pythium keratitis by PCR DNA sequencing from January 2014 to July 2017. Interventions were categorised into medical management (MM) (topical azithromycin and linezolid with oral azithromycin at presentation), surgery (S) (therapeutic penetrating keratoplasty, TPK), surgical adjunct (SA) (cryotherapy±alcohol with TPK) and medical adjunct (MA) (MM after TPK). RESULTS: Primary treatment included MM (1 eye), SA (3 eyes) and S (42 eyes). Recurrence occurred in 27/43 eyes (MM+S group). Second surgery (S) was required in 11 eyes (TPK-2), with additional procedures (SA) in 10 eyes and evisceration in five eyes. 8/43 eyes received MA after TPK-1. One eye required TPK-3. Recurrence occured in all eyes that received MA (100%) and in 28 of 54 TPKs (51.8%) (TPK 1+2+3) in 42 eyes. Recurrence was noted in 1/14 (7.1%) that underwent SA. CONCLUSION: The currently available and recommended treatment for Pythium keratitis is surgical by means of a TPK and in worse cases evisceration. In our study, MM/MA measures showed no benefit with recurrence or worsening of infection requiring resurgery. Almost 50% of TPKs had a recurrence requiring resurgery. However, adjunctive procedures during TPK appear to have additional benefit with low risk of recurrence and could be included as routine care.

Metaanalysis of cataract development after phakic intraocular lens surgery.

We performed a systematic literature review to determine the incidence of and predisposing factors for cataract after phakic intraocular lens (pIOL) implantation. Of the 6338 eyes reported, 4.35% were noted to have new-onset or preexisting progressive cataract. The incidence of cataract formation was 1.29%, 1.11%, and 9.60% with anterior chamber, iris-fixated, and posterior chamber (PC) pIOLs, respectively. In the PC pIOL group, early cataract formation was related to surgical trauma and late-onset cataract was related to IOL-crystalline lens contact. Analysis of cataract progression in eyes with preexisting cataract showed a progression rate of 29.5% after pIOL surgery. These results suggest that cataract formation is most likely to occur after PC pIOL implantation. Patients with preexisting progressive cataract should be informed about the possibility of cataract progression and possible need for cataract surgery after pIOL implantation. Cataract surgical intervention resulted in restoration of visual acuity.

Unusual ulcerative keratitis caused by Prototheca wickerhamii in a diabetic patient.

The purpose of the study was to report a case of ulcerative keratitis caused by an unusual algae Prototheca wickerhamii in a diabetic patient. This study design was a case report. A 46-year-old male, who was a known diabetic for 3 years, had an injury to the left cornea with the sparks of fire from wielding at work that developed into an ulcerative keratitis over a period of next 3 months as the patient was not on any medication. Corneal scraping culture report and Vitek 2 system investigation result confirmed it to be a P. wickerhamii infection. The patient was started on intensive topical 1% voriconazole and 5% natamycin for 1 month and with no improvement subsequently underwent penetrating keratoplasty. No recurrence of infection postoperatively was noted. This opportunistic algae rarely known to cause human eye infections is so far reported in either patients with severe systemic immunosuppression causing posterior segment eye involvement or as postcorneal surgery infections. We report an ulcerative keratitis by P. wickerhamii in a diabetic patient post corneal trauma with no prior ocular surgery.

Analysis of candidate genes ZEB1 and LOXHD1 in late-onset Fuchs' endothelial corneal dystrophy in an Indian cohort.

BACKGROUND: Fuchs' endothelial corneal dystrophy (FECD) is a complex degenerative disease of the corneal endothelium with genetic predisposition. Pathogenic rare variants have been identified in SLC4A11, LOXHD1, ZEB1, and AGBL1. Association of single nucleotide polymorphisms (SNPs) and CTG trinucleotide repeat expansions in the intron of TCF4 gene to FECD has been studied across multiple ethnicities. Recently, genome-wide association studies have also identified KANK4, LAMC1, and ATP1B1 as novel loci for FECD. Here, we report the contribution of ZEB1 and LOXHD1 genes in our sporadic late-onset FECD cohort. MATERIALS AND METHODS: In the experimental study, coding regions of ZEB1 and LOXHD1 were screened by Sanger DNA sequencing in 52 late-onset and 5 early-onset FECD cases of Indian origin, recruited at a tertiary eye care center. Further, bioinformatics analysis was done. RESULTS: One reported missense mutation, c.2522A>C; p.(Q841P), and one variant of uncertain significance (VUS), c.619A>G; p.(S207G), were identified in the ZEB1 gene. One VUS, c.6413G>Ap.(R2138Q), was observed in LOXHD1. A 3D structural bioinformatic analysis of the missense variant in LOXHD1 predicted the variant to affect the structure-function relationship of the protein. DISCUSSION: While mutations in ZEB1 contributed to 2% of the late-onset FECD cases, the exact role of the two VUS identified in ZEB1 and LOXHD1 in FECD pathogenesis needs to be studied.

Novel SLC4A11 mutations in patients with recessive congenital hereditary endothelial dystrophy (CHED2). Mutation in brief #958. Online.

Autosomal recessive congenital hereditary endothelial dystrophy (CHED2) is a severe and rare corneal disorder that presents at birth or shortly thereafter, characterized by corneal opacification and nystagmus. Recently the gene for CHED2 was identified and seven different mutations in the SLC4A11 gene were reported. Here, we report seven novel mutations and two previously identified mutations in families from India and the United Kingdom with recessive CHED. The novel changes include two nonsense (p.Trp240X; p.Gln800X) three missense (p.Glu143Lys; p.Cys386Arg; p.Arg755Trp) and two splice site mutations (c.2240+1G>A; c.2437-1G>A). Interestingly, the c.2398C>T (p.Gln800X) and c.2437-1G>A identified in two affected siblings represent the first compound heterozygous mutations in the SLC4A11 gene.

Association of polymorphisms in the intron of TCF4 gene to late-onset Fuchs endothelial corneal dystrophy: An Indian cohort study.

PURPOSE: Fuchs endothelial corneal dystrophy (FECD) is a progressive degenerative disease of the corneal endothelium. It is genetically heterogeneous and follows either an autosomal dominant or sporadic pattern of inheritance. Here, we have explored the association of four previously reported intronic single nucleotide polymorphisms and intronic CTG repeat expansions in TCF4 gene to FECD in an Indian cohort. METHODS: The cohort consisting of 52 sporadic late-onset cases, 5 early-onset cases, and 148 controls was taken for the study. rs2286812 and rs613872 were genotyped by allele specific polymerase chain reaction (ASPCR) and PCR-based restriction digestion, respectively; rs17595731 and rs9954153 were genotyped by Taqman assay using real-time PCR. The quantitative assessment of the CTG repeat region was performed by PCR/Sanger DNA sequencing. The repeats were assessed qualitatively by short tandem repeat and triplet repeat primed PCR assays. The statistical analysis was performed using two-tailed Fisher's exact probability test. RESULTS: SNPsrs613872 (G/T) for the 'G' allele (P value: 4.57 × 10-5) and rs17595731 (C/T) for the 'C' allele (P value: 1.87 × 10-5), respectively, showed a significant association to sporadic late-onset FECD. CTG repeat expansions were found to be associated with FECD with a P value = 2.4 × 10-3. CONCLUSION: rs613872, rs17595731, and CTG repeat expansions in intronic region of TCF4 are associated with increased risk of sporadic late-onset FECD in the Indian cohort studied.

Corneal Collagen Cross-Linking for Keratoconus in Pediatric Patients-Long-Term Results.

PURPOSE: To report the long-term outcome of corneal collagen cross-linking (CXL) for progressive keratoconus in pediatric patients. METHODS: "Epithelium-off" CXL was performed in pediatric eyes with progressive keratoconus. Spectacle-corrected distance visual acuity (CDVA), retinoscopy, topography, and tomography were documented preoperatively and postoperatively at 3 months, 6 months, 1 year, and annually thereafter. RESULTS: A total of 377 eyes of 336 pediatric patients aged 8 to 18 years with progressive keratoconus underwent CXL. Of these, 194 eyes had a follow-up beyond 2 years and up to 6.7 years. At last follow-up, there was significant improvement in mean CDVA from 0.33 ± 0.22 to 0.27 ± 0.19 logMAR (P ≤ 0.0001), reduction in mean topographic astigmatism from 7.22 ± 3.55 to 6.13 ± 3.28 D (P = 0.0001), mean flattening of 1.20 ± 3.55 diopters in maximum keratometry (Kmax) (P = 0.0002), and mean corneal thinning of 31.1 ± 36.0 µm (P < 0.0001) after CXL. The mean change in Kmax was most significant in moderately advanced keratoconus (average keratometry 48-53 diopters). Central cones showed more corneal flattening than peripheral cones. Stabilization or flattening of Kmax was seen in 85% of eyes at 2 years and in 76% after 4 years. Stabilization or improvement of CDVA was seen in 80.1% of eyes at 2 years and in 69.1% after 4 years. CONCLUSIONS: CXL remains effective in stabilizing keratoconus for longer than 2 years in a majority of pediatric eyes. Flattening of Kmax was greater in moderately advanced keratoconus and central cones. Long-term follow-up beyond 4 years, however, revealed that a few eyes showed features suggestive of reversal of the effect of CXL.