Scleral lens induced short term corneal changes in eyes with Pellucid Marginal Degeneration.

PURPOSE: To investigate the short-term effect of scleral lens (SL) on corneal curvature and corneal oedema in Pellucid Marginal Degeneration (PMD) eyes. METHODS: Corneal anterior, posterior curvature and corneal thickness were measured in 14 eyes of 14 PMD participants with Schiempflug imaging at different corneal diameters and meridians at baseline and after 6 h of SL wear. RESULTS: There was a significant flattening (up to 0.26 mm) of the anterior corneal curvature noted in the inferotemporal quadrant (from 210 to 255 degree at 2 mm, 8 mm and 10 mm corneal diameter), inferonasal quadrant (from 285 to 345 degree at 6 mm and 8 mm corneal diameter), and inferiorly at 2 mm and 10 mm corneal diameter (p < 0.05). Similarly, posterior corneal curvature showed statistically significant steepening mostly in inferotemporal quadrants (from 195 to 255 degree from 4 mm to 8 mm corneal diameter) and inferonasally at 2 mm and 4 mm corneal diameter (p < 0.05). A statistically significant increase in the corneal thickness noted in different corneal diameters with corneal oedema ranging from 2.10 % to 4.00 % after 6 h of SL wear. A gradual increase in corneal oedema was noted form centre to periphery. The baseline central fluid reservoir thickness (FRT) was 341.07 ± 139.8 which reduced to 276.71 ± 114.32 µm after 6 h of lens wear. No significant correlation was noted between corneal oedema with different parameters like initial and final FRT, change in anterior and posterior corneal curvature, and lens thickness (p > 0.05). CONCLUSIONS: Short-term SL wear induced a clinically acceptable range of corneal oedema. A clinically significant flattening in anterior curvature and minimal steepening in posterior curvature were noted. Practitioners should be careful while measuring corneal parameters in PMD eyes wearing SL, as these alterations can provide false impression of disease progression.

A case of granulomatosis with polyangiitis-associated scleritis presenting as conjunctivitis.

A 42-year-old male presented initially with conjunctivitis and was treated with topical medical medications without any improvement. He developed ocular pain subsequently and further examination revealed lid edema, conjunctival hyperemia with chemosis, matting of lashes with yellowish discharge, and deeper episcleral congestion which did not blanch with topical vasoconstrictor. Subsequent laboratory investigation revealed positive cytoplasmic-antineutrophil cytoplasmic antibody (Anti-PR 3 antibody). He continued to develop recurrences and finally responded to oral azathioprine. Granulomatosis with polyangitis may rarely present as conjunctivitis and subsequently manifest as scleritis.

Unique cytokine signature in ocular Stevens-Johnson syndrome non-responders.

PURPOSE: To clinically define a subset of patients with chronic ocular Stevens-Johnson syndrome non-responders (SJS-NR) and analyze their cytokine profile compared to clinical responders (SJS-CR). METHODS: A total of 32 SJS cases (n = 32, 64 eyes) managed over a period of three years were segregated into clinical responders (n = 24, 48 eyes) and non-responders (n = 8, 16 eyes). Cases were determined as non-responders based on persistent, refractory, and non-mechanical inflammation of the conjunctiva. Age- and sex-matched healthy controls (n = 25, 50 eyes) were recruited. Tear specimens collected using Schirmer's strip were profiled for 27 cytokines using an immunoassay-based 27-bioplex array. RESULTS: Tear cytokine profiling revealed 18 cytokines to be differentially expressed in SJS-NR compared to SJS-CR. While PDGF-BB, IL-4, IL-1ß, VEGF, IL-12p70, IFN-γ, IL-9, and IL-1RA were upregulated, GM-CSF, eotaxin, IP-10, IL-10, MCP-1, G-CSF, IL-6, IL-13, and bFGF were downregulated in SJS-NR compared to SJS-CR. The cytokines IL-13, IL-10, and IP-10 were decreased in both SJS-NR and SJS-CR compared to controls. CONCLUSION: The inflammation in SJS-NR continues to worsen despite the correction of mechanical causes, resulting in progressive deterioration of the cornea. The cytokine profile of SJS-NR was remarkably different from that of SJS-CR, indicating a T helper 2-type protective proliferative response and an impaired migratory potential of the conjunctival epithelium. These factors could possibly lead to poor healing of the corneal epithelium in a markedly pro-inflammatory and pro-angiogenic milieu. The top four differentially expressed cytokines, PDGF-BB, IL-4, IL-10, and IL-6, are proposed as potential biomarkers of SJS-NR.

Aberration change after scleral lens wear in eyes with pellucid marginal degenerations.

PURPOSE: To investigate the impact of scleral lenses (SLs) on higher-order aberrations (HOAs), corrected distance visual acuity (CDVA), and contrast sensitivity (CS) in pellucid marginal degeneration (PMD) eyes. METHODS: SLs were fitted in 24 eyes diagnosed with PMD. CDVA, CS, and HOAs were measured at baseline and with the lens on the eye. The HOAs were measured using an i-Trace aberrometer. RESULTS: A statistically significant improvement was noted in CDVA ( P < 0.001) with BSS lenses (0.05 ± 0.04) compared to baseline (0.42 ± 0.06). Front surface eccentricity 1 (FSE1) lens provided the best CDVA in most of the eyes. The baseline CS of 1.24 ± 0.74 improved to 1.58 ± 0.48 with SL and reported a statistically significant improvement ( P < 0.001) and a gain of 6 letters. The baseline higher order-root mean square (HO-RMS) was 0.89 ± 0.53 µm, which reduced to 0.38 ± 0.24 µm ( P < 0.001), and RMS coma of 0.45 ± 0.29 µm improved to 0.20 ± 0.12 µm ( P < 0.001). Though there was a marginal reduction from 0.04 ± 0.14 to 0.03 ± 0.07, RMS spherical aberration did not show any statistically significant difference ( P = 0.37). RMS secondary astigmatism reduced from 0.17 ± 0.15 µm to 0.08 ± 0.12 µm ( P = 0.007), and RMS trefoil reduced to 0.13 ± 0.09 µm from 0.64 ± 0.36 µm ( P < 0.001) with SLs and showed statistically significant improvement. CONCLUSION: SLs can be considered an effective option that corrects a significant amount of HOAs and enhances visual performances in PMD eyes.

Depth, size of infiltrate, and the microbe - The trio that prognosticates the outcome of infective keratitis.

PURPOSE: To analyze the influence of infiltrate size, depth, and organism on the outcome of microbial keratitis. DESIGN: Retrospective comparative study. METHODS: Medical records of patients with infective keratitis, who reported from January 2015 to December 2019 to a tertiary eye care center, were analyzed. Size and depth of ulcer at presentation were the factors used to group patients, and the influence on the outcome of the organism causing it was analyzed. Grouping was as follows: group A: ulcer size <6 mm/anterior to midstromal infiltrate, group B: ulcer < 6 mm/full-thickness infiltrate, group C: ulcer >6 mm/anterior to midstromal infiltrate, group D: ulcer > 6 mm/full-thickness infiltrate. Patients with viral keratitis or unidentified organism were excluded. Response to treatment and best-corrected visual acuity (BCVA) at the final follow-up were the outcome measures. RESULTS: In the study, 1117/6276 patients were included, with 60.8% patients in group A. A significant improvement in visual acuity was noted in groups A/B compared to groups C/D. Group A had the best response to medical management, irrespective of the organism. Higher risk for surgery was noted in group C compared to group B, with group A as the reference. Overall resolution with medical treatment was noted in 70% miscellaneous keratitis, 64.8% bacterial keratitis, 64.3% mixed keratitis, 62.5% acanthamoeba keratitis, 52.6% fungal keratitis, and 12.1% Pythium keratitis. Bacteria and acanthamoeba responded better to medical management than fungal keratitis, whereas Pythium had the highest risk for surgery. CONCLUSION: An interplay between virulence of the organism along with depth and size of the infiltrate determines the outcome of microbial keratitis.

Necrotizing Scleritis: A Review.

Necrotizing scleritis is the most destructive and vision-threatening form of scleritis. Necrotizing scleritis can occur in systemic autoimmune disorders and systemic vasculitis, as well as following microbial infection. Rheumatoid arthritis and granulomatosis with polyangiitis remain the commonest identifiable systemic diseases associated with necrotising scleritis. Pseudomonas species is the most common organism causing infectious necrotizing scleritis, with surgery the most common risk factor. Necrotizing scleritis has the highest rates of complications and is more prone to secondary glaucoma and cataract than other phenotypes of scleritis. The differentiation between non-infectious and infectious necrotizing scleritis is not always easy but is critical in the management of necrotizing scleritis. Non-infectious necrotizing scleritis requires aggressive treatment with combination immunosuppressive therapy. Infectious scleritis is often recalcitrant and difficult to control, requiring long-term antimicrobial therapy and surgical debridement with drainage and patch grafting due to deep-seated infection and the avascularity of the sclera.

Keratoprosthesis in dry eye disease.

Bilateral corneal blindness with severe dry eye disease (DED), total limbal stem cell deficiency with underlying corneal stromal scarring and vascularization, combined with adnexal complications secondary to chronic cicatrizing conjunctivitis is a highly complex situation to treat. In such eyes, procedures such as penetrating keratoplasty alone or combined with limbal stem cell transplantation are doomed to fail. In these eyes, keratoprosthesis (Kpro) or an artificial cornea is the most viable option, eliminating corneal blindness even in eyes with autoimmune disorders such as Stevens-Johnson syndrome, ocular mucous membrane pemphigoid, Sjogren's syndrome, and nonautoimmune disorders such as chemical/thermal ocular burns, all of which are complex pathologies. Performing a Kpro in these eyes also eliminates the need for systemic immunosuppression and may provide relatively early visual recovery. In such eyes, the donor cornea around the central cylinder of the Kpro needs to be covered with a second layer of protection to avoid desiccation and progressive stromal melt of the underlying cornea, which is a common complication in eyes with severe DED. In this review, we will focus on Kpro designs that have been developed to survive in eyes with the hostile environment of severe DED. Their outcomes in such eyes will be discussed.

E-PIX: An enhanced grading for acute ocular burns.

An enhanced online and manual grading system, based on the I's and E's, for acute ocular chemical injuries is being proposed. E-PIX is designed to be an online/manual grading system that includes all the parameters that adversely affect the outcome of acute chemical injuries. The importance of addressing the I's and E's in chemical burns cannot be underestimated. These include the need for the documentation and management of epithelial defect (E), intraocular pressure (P) (IOP), ischemia (scleral) (I), and exposure (X) (acronym - E-PIX). Epithelial defect includes that involving the limbus (L), along with conjunctival (C), corneal (K), and tarsal (T). These additional parameters are graded and represented as an annotation along with the limbal grade providing a comprehensive grading for the injury. A manual entry sheet and a freely accessible online grade generator are a part of the system. The proposed enhanced grading offers a final annotation that provides a clear understanding of all factors that can lead to vision-threatening complications ensuring their assessment and hence subsequently their addressal to improve outcomes, if abnormal. The prognostication continues to be based on the grade of limbal involvement. The additional annotations impact prognosis and outcome if not addressed. Including the laterality of injury provides, in addition, a futuristic understanding of available options. The grade generator retains the flexibility to be dynamic with changes reflecting upon the healing process in the acute stage. The proposed system aims to provide primary and tertiary caregivers alike with a uniform grading system.

Dry eye module - An application intelligence platform for diagnosing and monitoring dry eye disease.

Dry Eye Module (DEM), a software application, was developed to facilitate the streamlining of dry eye evaluation and documentation, to unify diagnostic jargon, and to analyze data input to generate a dry eye diagnostic report. This diagnostic report generated is based on the current understanding of dry eye diagnostic algorithms (Dry Eye Workshop 2 [DEWS2]/Asia Dry Eye Society [ADES]). Apart from its plausible role in aiding unprecedented multicentric dry eye demographic data collection, the application software can generate a customized referral letter to the rheumatologist, highlighting the salient ophthalmic features to be shared. DEM uses schematic illustrations to depict eyelid, conjunctival, and corneal parameters that impact the ocular surface in dry eyes that can be captured and compared during serial visits. Furthermore, DEM displays a symptom sign trend chart that graphically represents improvement/stability or worsening of the subjective and objective dry eye status. DEM can generate a curated prescription using preloaded advice templates. DEM includes facility for state-of-the-art advanced dry eye diagnostic reporting for super specialty use. The addition of DEM to the dry eye diagnostic armamentarium would help bridge the current unmet needs of dry eye evaluation. These are lack of uniform reporting, lack of multicentric data on a unified platform, the inability to ensure complete evaluation, inability to avoid lacunae during follow-up visits, and the lack of a simple patient-ophthalmologist and an ophthalmologist-rheumatologist interface.

Aqueous deficiency dry eye in post conjunctivitis cicatrization - Effect of deep thermal punctal cautery.

Purpose: To evaluate the effect of deep thermal punctal cautery in eyes with post-conjunctivitis cicatrization. Methods: This retrospective study consisted of patients who underwent deep thermal punctal cautery for post-conjunctivitis dry eye (PCDE). The diagnosis was based on a history suggestive of viral conjunctivitis in past followed by the onset of present clinical features of aqueous deficiency dry eye (ATD). All patients underwent a rheumatological evaluation to rule out underlying systemic collagen vascular disease as a cause for dry eye. The extent of cicatricial changes was noted. Best-corrected visual acuity (BCVA), Schirmer's test, and fluorescein staining score (FSS; total score of 9) were analyzed pre- and post-cautery. Results: Out of 65 patients (117 eyes), 42 were males. The mean age at presentation was 25.769 ± 12.03 years. Thirteen patients presented with unilateral dry eye. Pre-cautery BCVA (logarithm of the minimum angle of resolution [logMAR]) and Schirmer's test (mm) improved from 0.5251 ± 0.662 to 0.372 ± 0.595 (P value = 0.000, 95% confidence interval [CI]: 0.09-0.22), and 1.952 ± 2.763 to 4.929 ± 4.338 (P value = 0.000, 95% CI: -3.79--2.17); post-cautery, respectively. The pre-cautery FSS of 5.9 ± 2.82 reduced to 1.58 ± 2.38 (P value = 0.000, 95% CI: 3.46-5.17) post-cautery. The mean follow-up was 11.22 ± 13.32 months. No progression in cicatricial changes was noted in any eye during the follow-up. Re-canalization rate was 10.64%, and repeat cautery was performed with successful closure of puncta. Conclusion: Symptoms and clinical signs of ATD in PCDE patients improve with punctal cautery.

Ocular surface sphingolipids associate with the refractory nature of vernal keratoconjunctivitis: newer insights in VKC pathogenesis.

BACKGROUND: The etiopathogenesis of vernal keratoconjunctivitis (VKC) is incompletely understood. Bioactive lipids play a key role in allergic disorders. This study focused on the sphingolipid metabolism on the ocular surface of VKC and to explore if it has a contributory role in the refractoriness of the disease. METHODS: Active VKC cases, (n=87) (classified as mild/moderate and severe/very severe based on the disease symptoms) and age-matched healthy controls (n=60) were recruited as part of a 2-year prospective study at a tertiary eye care centre in South India. Conjunctival imprint cytology was used to assess gene expression of enzymes of sphingolipids metabolism. Sphingolipids were estimated in the tears by LC-MS/MS analysis. In vitro study was done to assess IgE-induced alterations in sphingosine-1-phosphate (S1P) receptor expression and histone modification in cultured mast cells. RESULTS: Significantly altered gene expression of the sphingolipids enzymes and S1P receptor (SIP3R) were observed in conjunctival imprint cells of VKC cases. Pooled tears analysis revealed significantly lowered levels of S1P(d17:0), S1P(d20:1) (p<0.001) and S1P(d17:1) (p<0.01) specifically in severe/very severe VKC compared with both mild/moderate VKC and control. Cer(d18:/17:0) (p<0.001), ceramide-1-phosphate (C1P)(d18:1/8:0) (p<0.01) and C1P(d18:1/2.0 (p<0.05) were lowered in severe/very severe VKC compared with mild/moderate VKC. Cultured mast cells treated with IgE revealed significantly increased gene expression of S1P1 and 3 receptors and the protein expression of histone deacetylases (1, 6). CONCLUSION: Altered sphingolipid metabolism in the ocular surface results in low tear ceramide and sphingosine levels in severe/very severe VKC compared with the mild/moderate cases. The novel finding opens up fresh targets for intervention in these refractory cases.

Possible Synergistic Role of Cryo-Alcohol Therapy in Infectious Scleritis-Scope and Rationale for Expanding Indications and Review of the Literature.

PURPOSE: The purpose of this study was to highlight the use of topical ethanol as an adjunct to cryotherapy, termed cryo-alcohol therapy, in the management of fungal/acanthamoeba scleritis along with a review of the literature. METHOD: Retrospective interventional case reports of fungal and acanthamoeba scleritis along with a review of the literature. RESULTS: The patient with circumferential necrotic fungal scleritis resolved in 6 weeks achieving a best-corrected visual acuity (BCVA) of 20/20, and the patient with acanthamoeba scleritis is awaiting optical keratoplasty after complete resolution in 8 weeks. The literature review from January 1990 to December 2020 revealed BCVA >20/200 in 50% of the eyes with a mean time to resolution being 4.16 ± 2.13 months in fungal scleritis, with 27.02% and 75% of the eyes requiring evisceration in fungal and acanthamoeba scleritis, respectively. CONCLUSIONS: Cryotherapy is a useful adjunct in managing refractory infectious scleritis, and its efficacy can be enhanced by combining the use of topical ethanol to aid in faster recovery and reduce visual morbidity.

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.

Perioperative nuances of cataract surgery in ocular surface disorders.

Ocular surface disorders (OSDs) constitute a varied spectrum of conditions that could be associated with dryness, compromised limbal status, varying grades of forniceal obliteration, corneal scars, and a possible underlying immune etiology. These associations adversely impact surgical outcomes in the eye. One of the treatable causes of decreased vision in these eyes is cataracts which could be secondary to the disease, its treatment, or age-related. The compromised ocular surface status can interfere with decision-making regarding the technique of cataract surgery, preoperative biometry for intraocular lens (IOL) power calculation, and intraoperative visibility, increasing the possibility of complications and compromising the final visual outcome. The postoperative course can be affected by complications, including melt and infection. Stabilization of the ocular surface by medical or surgical means, and appropriate management of underlying immune etiology, if any, helps improve and maintain a healthy ocular surface, optimizing cataract outcomes. With the help of pre, intra, and postoperative tools and means, such as punctal occlusion, ocular surface reconstruction, systemic immunosuppression, illuminators, capsule staining dyes, optical iridectomy, prosthetic replacement of the ocular surface ecosystem (PROSE) lenses, and others, the visual outcome post-cataract surgery in these eyes can be maximized. This article highlights the nuances of performing cataract surgery in various OSDs and the need to have a comprehensive stepwise approach is emphasized.

Pythium insidiosum Keratitis: Past, Present, and Future.

Pythium insidiosum (PI) is an oomycete, a protist belonging to the clade Stramenopila. PI causes vision-threatening keratitis closely mimicking fungal keratitis (FK), hence it is also labeled as "parafungus". PI keratitis was initially confined to Thailand, USA, China, and Australia, but with growing clinical awareness and improvement in diagnostic modalities, the last decade saw a massive upsurge in numbers with the majority of reports coming from India. In the early 1990s, pythiosis was classified as vascular, cutaneous, gastrointestinal, systemic, and ocular. Clinically, morphologically, and microbiologically, PI keratitis closely resembles severe FK and requires a high index of clinical suspicion for diagnosis. The clinical features such as reticular dot infiltrate, tentacular projections, peripheral thinning with guttering, and rapid limbal spread distinguish it from other microorganisms. Routine smearing with Gram and KOH stain reveals perpendicular septate/aseptate hyphae, which closely mimic fungi and make the diagnosis cumbersome. The definitive diagnosis is the presence of dull grey/brown refractile colonies along with zoospore formation upon culture by leaf induction method. However, culture is time-consuming, and currently polymerase chain reaction (PCR) method is the gold standard. The value of other diagnostic modalities such as confocal microscopy and immunohistopathological assays is limited due to cost, non-availability, and limited diagnostic accuracy. PI keratitis is a relatively rare disease without established treatment protocols. Because of its resemblance to fungus, it was earlier treated with antifungals but with an improved understanding of its cell wall structure and absence of ergosterol, this is no longer recommended. Currently, antibacterials have shown promising results. Therapeutic keratoplasty with good margin (1 mm) is mandated for non-resolving cases and corneal perforation. In this review, we have deliberated on the evolution of PI keratitis, covered all the recently available literature, described our current understanding of the diagnosis and treatment, and the potential future diagnostic and management options for PI keratitis.

Update on diagnosis and management of refractory corneal infections.

Infectious keratitis is a medical emergency resulting in significant visual morbidity. Indiscriminate use of antimicrobials leading to the emergence of resistant or refractory microorganisms has further worsened the prognosis. Coexisting ocular surface diseases, delay in diagnosis due to inadequate microbiological sample, a slow-growing/virulent organism, or systemic immunosuppressive state all contribute to the refractory response of the ulcer. With improved understanding of these varied ocular and systemic factors contributing to the refractory nature of the microbes, role of biofilm formation and recent research on improving the bioavailability of drugs along with the development of alternative therapies have helped provide the required multidimensional approach to effectively diagnose and manage cases of refractory corneal ulcers and prevent corneal perforations or further dissemination of disease. In this review, we explore the current literature and future directions of the diagnosis and treatment of refractory keratitis.

The evolution of the modified osteo-odonto-keratoprosthesis, its reliability, and long-term visual rehabilitation prognosis: An analytical review.

An exhaustive search of the world's literature was performed to analyze all case reports and series on the modified osteo-odonto-keratoprosthesis (MOOKP) published up to January 2022. The demographic profile, the primary indication for surgery, surgical technique variations, postoperative medical management, long-term functional and anatomical outcomes, and intra- and postoperative complications were analyzed and compared. Additionally, some of the authors' (GI, VP, and GA) unpublished MOOKP cases were studied. An extensive literature search yielded 37 case series and case reports. Overall, 958 patients were analyzed. The most common indication for surgery was autoimmune disease (39.1%), closely followed by chemical injury (38.8%). The most common intraoperative complications (21.67%) included maxillofacial, vitreous hemorrhage/vitritis, and mucosal. The most common postoperative complications (78.4%) were lamina and oral mucosa-associated, secondary glaucoma, and choroid/retinal detachment. Follow-up periods ranged from one to 364 months (median: 36.7 months). Altogether, 78% of patients achieved a visual acuity of 20/400 or better at the end of the follow-up period, and 91.2% improved at least temporarily after MOOKP surgery. Mean anatomic success at the end-of-follow-up for all patients was 88.25% (range, 50-100%). The long-term anatomic and functional success of the MOOKP makes it a reliable option for visual rehabilitation in patients with bilateral corneal blindness and end-stage ocular surface disease. This review aims to describe the evolution of the MOOKP procedure, analyzing all published case series for its long-term reliability, visual and anatomical outcomes, complications, and future directions.

Pythium insidiosum keratitis - A review.

Pythium insidiosum is an oomycete and is also called "parafungus" as it closely mimics fungal keratitis. The last decade saw an unprecedented surge in Pythium keratitis cases, especially from Asia and India, probably due to growing research on the microorganism and improved diagnostic and treatment modalities. The clinical features such as subepithelial infiltrate, cotton wool-like fluffy stromal infiltrate, satellite lesions, corneal perforation, endoexudates, and anterior chamber hypopyon closely resemble fungus. The classical clinical features of Pythium that distinguish it from other microorganisms are reticular dots, tentacular projections, peripheral furrowing, and early limbal spread, which require a high index of clinical suspicion. Pythium also exhibits morphological and microbiological resemblance to fungus on routine smearing, revealing perpendicular or obtuse septate or aseptate branching hyphae. Culture on blood agar or any other nutritional agar is the gold standard for diagnosis. It grows as cream-colored white colonies with zoospores formation, further confirmed using the leaf incarnation method. Due to limited laboratory diagnostic modalities and delayed growth on culture, there was a recent shift toward various molecular diagnostic modalities such as polymerase chain reaction, confocal microscopy, ELISA, and immunodiffusion. As corneal scraping (10% KOH, Gram) reveals fungal hyphae, antifungals are started before the culture results are available. Recent in vitro molecular studies have suggested antibacterials as the first-line drugs in the form of 0.2% linezolid and 1% azithromycin. Early therapeutic keratoplasty is warranted in nonresolving cases. This review aims to describe the epidemiology, clinical features, laboratory and molecular diagnosis, and treatment of Pythium insidiosum keratitis.