Microsporidial keratitis in India: 16S rRNA gene-based PCR assay for diagnosis and species identification of microsporidia in clinical samples

Purpose: To evaluate 16S rRNA-based polymerase chain reactions for the detection and species identification of the microsporidia that cause keratitis. Methods: Of the 5892 cases of microbial keratitis seen between September 2002 and December 2005, 31 (0.5%) microscopically diagnosed cases of microsporidial keratitis were included in the test group; 103 patients with nonmicrosporidial keratitis constituted the control group. A 16S rRNA-based pan-microsporidian PCR was chosen for the detection of microsporidian DNA. Species level identification was made using species-specific primer sets of Encephalitozoon spp (E. cuniculi, E. hellem, and E. intestinalis). Sequencing and BLAST analysis of amplicons obtained with pan-microsporidian primers were performed for validation. Results: The corneal scrapings from 26 of 31 cases in the test group and 2 of 103 cases in the control group showed a 250- to 280-bp amplicon in PCR by pan-microsporidian primers (sensitivity of 83% and specificity of 98%). The amplicons of 13 of 26 test group samples were identified by species-specific PCR: E. cuniculi, n = 7 (549 bp); E. hellem; n = 3 (549 bp); E. intestinalis; n = 1 (520 bp). The two cases in the control group were identified to be E. cuniculi. The remaining 15 cases (test group) were confirmed to be Vittaforma corneae by sequencing and BLAST analysis. All species were confirmed by sequencing and database homology comparison. Conclusions: This study is the first to validate PCR-based assays for detection of microsporidial DNA in corneal scrapings. Pan microsporidian PCR can be a useful adjunct with smear examination in the diagnosis of microsporidial keratitis

Clinical spectrum in microbiologically proven Demodex blepharokeratoconjunctivitis: An observational study

Purpose: To study the demographic, clinical, and microbiological profile of Demodex-related blepharokeratoconjunctivitis (BKC) at a tertiary eye care hospital. Methods: This retrospective observational study was conducted from January 2016 to September 2022. It included 83 patients with microbiologically proven Demodex BKC who presented to the cornea department of our tertiary care eye center. The clinical, microbiological, and demographic data of the 83 cases were analyzed. Results: Of the 83 cases, 57 (68.67%) were younger than 40 years, and 25 (30.12%) were below 20. Most patients presented with a good visual acuity of 20/40 or better (93 eyes; 84.55%). The disease was unilateral in 55 patients and bilateral in 28. Cylindrical dandruff was the predominant presentation noted in 61 eyes (54.95%), followed by corneal scarring in 47 eyes (42.34%) and corneal vascularization in 40 eyes (36.04%). On light microscopy, 87.95% of the positive samples were identified as Demodex folliculorum, 7.23% as Demodex brevis, and 6.02% remained unidentified. Tea tree oil and lid scrubs eradicated the disease in most patients clinically (75/83, 90.36%). Conclusion: The spectrum of BKC includes both lid signs and corneal involvement. It can be a cause of recurrent BKC and detection of the mite by microscopic evaluation of the lashes can confirm the diagnosis. In most cases, the tea tree oil can effectively manage this condition. However, low doses of topical steroids are needed to control the inflammation in patients with corneal involvement

Update on Pathologic Diagnosis of Corneal Infections and Inflammations

One of the most frequent types of corneal specimen that we received in our pathology laboratory is an excised corneal tissue following keratoplasty. Several of these cases are due to corneal infections or the sequelae, like corneal scar. Advances in the histological and molecular diagnosis of corneal infections and inflammations have resulted in rapid and accurate diagnosis of the infectious agent and in the overall understanding of the mechanisms in inflammatory diseases of the cornea. This review provides an update of histopathological findings in various corneal infections and inflammations

Congenital anomalies of lens shape

The crystalline lens is an important structure in the eye that starts to develop as early as the 22nd day of gestation, with further differentiation that continues after the induction. Congenital anomalies of the lens may involve the size, shape, and position of the lens. They may sometimes be associated with anterior segment dysgenesis or persistence of the tunica vasculosa lentis and hyperplastic vitreous and hyaloid system. Manifestations of anomalies of the lens shape are usually seen in early or late childhood however may sometimes be delayed into adulthood based on the level of visual impairment or the presence or absence of any syndromic associations. While lens coloboma has more often been reported in isolation, the more commonly implicated genes include the PAX6 gene, lenticonus in particular anterior is often part of Alport syndrome with extra-ocular manifestations in the kidneys and hearing abnormalities due to mutations in the alpha 5 chain of the Type IV collagen gene. Recognition of these manifestations and obtaining a genetic diagnosis is an important step in the management. The level of visual impairment and amblyopia dictates the outcomes in patients managed either conservatively with optical correction as well as surgically where deemed necessary. This review discusses the various anomalies of the lens shape with its related genetics and the management involved in these conditions

Anterior megalophthalmos: Is visual restoration possible?

We report two cases of anterior megalophthalmos with cataract. Both cases have megalocornea, cavernous anterior chamber, enlarged iris–lens diaphragm, and normal axial length. The vision was less due to cataract. To restore vision, phacoemulsification was performed in each eye in both cases. Intraoperatively, to overcome anatomical challenges, we made scleral tunnel incision, stained anterior capsule, and fixated intraocular lens (IOL) by different techniques. In the first case, IOL was fixated through the sclera, whereas in the second case, IOL stabilization was achieved by capturing the optic in anterior capsulorhexis margin and placing the haptics in sulcus. Successful vision was restored in both cases without pseudophacodonesis

Scleral thickness in normal Indian eyes measured using spectral domain anterior segment optical coherence tomography

Purpose: To establish normative data on anterior scleral thickness using the spectral domain anterior segment optical coherence tomography (AS-OCT). Methods: In total, 200 eyes of 100 healthy subjects underwent AS-OCT scans in the temporal and nasal quadrants. The scleral + conjunctival complex thickness (SCT) was measured by a single examiner. Mean SCT was analyzed for differences across age groups, gender, and location (nasal versus temporal). Results: Mean age was 46.4 ± 18.3 (21–84) years; male to female ratio was 54:46. Mean SCT (nasal + temporal) of the right eye (RE) was 682.3 ± 64.2 μm in males and 660.6 ± 57.1 μm in females. In the left eye (LE), it was 684.6 ± 64.9 μm in males and 661.8 ± 49.3 μm in females. These differences between male and female for both eyes were statistically significant (P = 0.006 and P = 0.002). The mean SCT of temporal and nasal quadrants in the RE was 678.54 ± 57.50 and 666 ± 66.2 μm, respectively. In the LE, the temporal mean SCT quadrant was 679.6 ± 55.8 μm, and the nasal was 668.6 ± 63.6 μm. Age had a negative correlation with SCT (−0.62 μm/year; P = 0.03), and males had a higher temporal SCT than females (22 μm higher; P = 0.03). After adjusting for age and gender in a multivariate analysis, temporal SCT was significantly (P < 0.001) higher than nasal SCT. Conclusion: In our study, mean SCT decreased with age and males had a higher temporal SCT. This is the first study to evaluate scleral thickness in the Indian population, and the data can be used as a baseline for comparing variations in scleral thickness in disease

Outcomes of keratoplasty in lattice corneal dystrophy in a large cohort of Indian eyes

Purpose: The purpose of this study is to evaluate the outcomes of keratoplasty for lattice corneal dystrophy (LCD) performed at a tertiary eye care center. Methods: A retrospective review of medical records of those patients who were clinically diagnosed to have LCD (72 eyes of 57 patients) and underwent either penetrating keratoplasty (PK, 58 eyes of 46 patients) or deep anterior lamellar keratoplasty (DALK, 14 eyes of 13 patients) between the years 1987 and 2014 was performed. The main outcome measures included demographics, clinical features, and outcomes of keratoplasty. Results: The median follow-up after keratoplasty was 3.1 years (interquartile range [IQR], 9 months to 9 years). The median best-corrected visual acuity (BCVA) was 0.18 (IQR, 0.10–0.48) (Snellen equivalent 20/30 [IQR, 20/25–20/60]) at 4 years postoperatively and 0.65 (IQR, 0.18-0.95) (Snellen equivalent 20/89 [IQR, 20/30–20/178]) at 10 years following surgery. DALK eyes had a significantly better BCVA than PK eyes at 2 years following keratoplasty. The median overall survival of grafts was 15.8 years. Late complications included recurrence of LCD (14 eyes), graft infiltrate (23 eyes), graft rejection (15 eyes), graft failure (16 eyes), and glaucoma (14 eyes). Conclusion: The outcomes of graft are similar following PK and deep anterior lamellar keratoplasty; however, the latter appears to provide slightly better visual outcome. Recurrence of dystrophy in the graft and graft infiltrates limit the overall graft survival in both the groups

Surgical treatment of chronically recurring pterygium

Purpose: To report the result of a combined surgical procedure of pterygium excision with simultaneous amniotic membrane transplant, conjunctival limbal autograft, and mitomycin C application in the management of two cases of chronically recurring pterygium. Methods: Report of two cases. Results: The two male patients, ages 24 and 42 years, had undergone six previous surgeries for pterygium, with and without adjunct procedures. In the follow-up period of 26 months for the first case and 25 months for the second case, no recurrence or complications were encountered. Conclusion: A combined procedure seems to be beneficial in cases of chronically recurring pterygia in younger patients. This approach may be considered when all other types of surgery have failed

Comparison of immersion ultrasonography, ultrasound biomicroscopy and anterior segment optical coherence tomography in the evaluation of traumatic phacoceles

Blunt ocular trauma in the elderly can result in anterior dislocation of the crystalline lens into the subconjunctival space (phacocele). Although rare, this presentation can be missed, especially if the patient presents several days after the injury and if the lid is not everted on examination. While a careful clinical examination is adequate in the diagnosis, imaging techniques can be put to use for the accurate location of the associated sclera rupture. We report three cases of post-traumatic phacocele wherein ultrasound biomicroscopy (UBM) was compared to the anterior segment optical coherence tomography (AS-OCT) and B-scan ultrasonography (B-scan), in order to establish the best imaging tool for this condition. We concluded, based on image quality, that UBM could be the imaging modality of choice to aid in the diagnosis of phacocele