In vivo confocal microscopy qualitative investigation of the relationships between lattice corneal dystrophy deposition and corneal nerves

Typical Manifestations of the Different Corneal Deposits by In Vivo Confocal Microscopy (IVCM): A Review

In vivo confocal microscopy (IVCM) is a highly useful tool in ophthalmology for investigating a wide range of corneal pathologies. It provides high resolution images with minimal light scattering and is particularly useful in determining the nature of various corneal deposits. Deposits may arise within any layer of the cornea and may occur due to various reasons such as infections (e.g., crystalline deposits), metabolic bodily processes, systemic diseases, pharmacological agents and toxins. Deposits may as a general rule, be linear versus non-linear in shape or hyperreflective or hyporeflective in nature. Non-linear deposits can further be subdivided into granular, round, amorphous, or whorl-like patterns of deposits. This article will attempt to not only summarise all of the currently recognised corneal deposits but also utilise the morphology of the varying types of corneal deposits as seen in IVCM and categorise them within a table.

In Vivo Confocal Microscopy Findings in Corneal Stromal Dystrophies

Background/Objectives: In this study, we aim to evaluate in vivo confocal microscopy (IVCM) findings of corneal stromal dystrophies (CSDs) including granular, macular and lattice corneal dystrophy that can be used for differential diagnosis and monitoring recurrences after surgical interventions. Methods: Patients diagnosed with CSD who were followed-up in the cornea and ocular surface unit were included in this study. IVCM was performed using the Heidelberg Retina Tomograph 3, Rostock Cornea Module (Heidelberg Engineering, Germany) and anterior segment optical coherence tomography (AS-OCT) imaging was performed using the Spectralis OCT (Heidelberg Engineering, Germany). The morphological structure, size and location of deposits, epithelial involvement and presence of inflammatory and dentritic cells were compared among the three stromal dystrophies. Results: A total of 72 eyes from 36 participants were included in this study. Twelve patients (33.33%) had granular corneal dystrophy (GCD), ten (27.77%) had macular corneal dystrophy (MCD) and fourteen (38.88%) had lattice corneal dystrophy (LCD). In GCD, highly reflective deposits varying in size (20 µm-300 µm) were observed. In MCD, diffuse hyperreflective stroma with dark striae, dentritic cells around deposits and abnormal keratocytes were observed. In LCD, there were branching, lattice-like and granular deposits with epithelial cell disruption in some of the eyes. In MCD, the central corneal thickness was thinner (449.44 ± 65.45 µm) compared to GCD and LCD (565.16 ± 49.62 µm and 569.91 ± 39.32 µm p < 0.001). Recurrence was observed in five patients following penetrating keratoplasty. Conclusions: IVCM is a valuable tool for distinguishing CSD subtypes and monitoring recurrence following surgical interventions.

Classic lattice corneal dystrophy: a brief review and summary of treatment modalities

PURPOSE

To provide a brief summary and comparison of the most recent literature on available and theorized treatment modalities for classic lattice corneal dystrophy (LCD). This paper aims to support practitioners in their management of this disease.

METHODS

A search was carried out on available literature through PubMed and Google Scholar of English language articles up to January 2023 that relate to the treatment of LCD. Due to scarcity of literature regarding specific novel therapies for LCD, results from other corneal pathologies (granular corneal dystrophy, corneal scarring) are sometimes included for contrast, which is clearly denoted.

RESULTS

LCD is a slowly progressive disease that leads to recurrent epithelial corneal erosions, stromal haze, corneal opacification, substantial discomfort, and visual impairment. Due to its autosomal-dominant inheritance pattern, this disease can persist throughout ancestral lines and requires consistent treatment and follow-up. An optimal management plan is necessary to (1) prolong years of life with best achievable visual acuity; (2) treat painful recurrent corneal erosions as they occur; (3) ensure proper follow-up throughout the life of a patient, as well as monitor at-risk offspring; and (4) monitor efficacy of treatment.

CONCLUSIONS

This paper addresses (1) treatment for early disease including corneal epithelial debridement, photo therapeutic keratectomy (PTK), femtosecond laser-assisted lamellar keratectomy (FLK), and others; (2) treatment for late disease including full thickness keratoplasties and anterior lamellar keratoplasties; and (3) potential future treatment considerations including a wide variety of topical/systemic, genetic, and regenerative approaches.

A Novel Heterozygous TGFBI c.1613C>A Pathogenic Variant is Associated With Lattice Corneal Dystrophy in a Chinese Family

PURPOSE

To investigate the gene mutations and relationship of clinical manifestation in a Chinese family with familial lattice corneal dystrophy (LCD).

DESIGN

Single-family case-control study.

METHODS

A family with familial LCD was recruited for this study. A total of 10 affected and 13 healthy family members participated in this research. Clinical features were examined by slit-lamp examination and anterior segment optical coherence tomography (AS-OCT). Peripheral blood samples were collected from each participant, and genomic DNA was extracted. Whole-exome sequencing (WES) analysis was performed, and the pathogenic variants of LCD were identified using bioinformatics tools and confirmed by Sanger sequencing.

RESULTS

Slit-lamp examination revealed diffuse grayish-white punctate, linear, and "lattice-like" opacities in the corneal epithelium and superficial corneal stroma. AS-OCT revealed an irregularly shaped cornea. The corneal epithelium and anterior corneal stroma showed high-reflective deposits and bulges. The clinical appearance of the patients fit the pattern and features of autosomal dominant inheritance of LCD type I (LCD I). A novel pathogenic variant of exon 12 in TGFBI was found by WES analysis, in which cytosine at position 1613 was substituted by adenine (c.1613C>A), and the amino acid was changed from threonine to lysine (p.T538K). Mutated genes and proteins were predicted to be deleterious.

CONCLUSION

A novel heterozygous pathogenic variant (c.1613C>A) of TGFBI was identified in the Chinese family with LCD I.

Combined Topography-Guided Trans-Epithelial PRK and PTK for Recalcitrant Recurrent Corneal Erosions in Lattice Corneal Distrophy

Purpose

To report morphologic and functional changes after topography-guided trans-epithelial photorefractive keratectomy (PRK) combined with phototherapeutic keratectomy (PTK) for recalcitrant recurrent corneal erosions in Lattice Corneal Dystrophy (LCD).

Methods

One case report.

Results

A 78-year-old man presented us with decreased visual acuity [20/100 in right eye (RE), and 20/400 in left eye (LE)], and redness with foreign body sensation in both eyes. Clinical examination revealed epithelial erosions, and linear stromal opacities involving the center of the cornea in both eyes, supporting the diagnosis of LCD. Several medical approaches including autologous serum, amniotic membrane extract, and nerve growth factor eye drops allowed a temporary improvement in symptoms. A single-step topography-guided trans-epithelial PRK combined with PTK (CIPTA^®2 software, iVis Technologies) was performed in both eyes. After surface ablation using PRK, PTK was performed using masking agents (1% hydroxy-methylcellulose) to smooth the ablated surface. Subsequently, 0.02% Mitomycin C was applied over the ablated surface. At the 3-month follow-up, a resolution of corneal erosions, and stromal opacities were observed in both eyes, with a visual improvement to 20/25 in the RE and 20/50 in the LE. Furthermore, spherical equivalent, keratometric astigmatism, and corneal morphological irregularity index improved.

Conclusion

Recalcitrant corneal erosions and stromal opacities in LCD may be successfully treated using combined topography-guided trans-epithelial PRK and PTK.