Lipid Keratopathy: A Review of Pathophysiology, Differential Diagnosis, and Management

Development of Crystalline Corneal Opacities (Steroid Keratopathy) in Dogs After Treatment With Ophthalmic Corticosteroids

PURPOSE

To retrospectively evaluate and describe the relationship between the use of topical corticosteroids and the development of crystalline corneal opacities (steroid keratopathy) in a colony of research Beagles and Beagle-derived dogs.

METHODS

Medical records of 73 purpose-bred Beagles and Beagle-derived dogs were reviewed from June 2012 to May 2021. All dogs were treated with topical ophthalmic corticosteroids for at least 21 days. In addition to regular ophthalmic examination, some dogs also had a systemic lipid profile (n = 6) performed to work up further and characterize the crystalline corneal opacities. Globes of 3 dogs were examined histopathologically.

RESULTS

Axial stromal crystalline corneal opacities were appreciated in 25 eyes of 14 dogs after a median of 141 days after initiating treatment (35-396 days). Multiple corticosteroids were used, including neomycin-polymyxin b-dexamethasone 0.1% ophthalmic ointment, prednisolone acetate 1% ophthalmic suspension, and difluprednate 0.05% ophthalmic emulsion (Durezol). Resolution of corneal opacity was documented in 4 of 25 eyes when ophthalmic corticosteroids were discontinued after a median of 406.5 days (271-416 days). Histopathologic examination revealed a dense band of acellular material, poorly staining with periodic acid-Schiff, subtending the corneal epithelium, and being surrounded by spindle cells.

CONCLUSIONS

This case series documents the onset of steroid keratopathy in Beagles and Beagle-derived dogs after treatment with ophthalmic corticosteroids. Clinical resolution of steroid keratopathy lesions may be possible after discontinuation of ophthalmic corticosteroids.

Prospective In Vivo Confocal Microscopy of the Central Cornea in Terrien Marginal Degeneration

PURPOSE

To analyze central corneal in vivo confocal microscopy (IVCM) in Terrien marginal degeneration (TMD).

METHODS

An observational prospective case-control study. Ten Finnish patients with TMD from a tertiary referral center were compared with 10 age- and sex-matched healthy volunteers. Seven patients had bilateral TMD. Age, anterior segment optical coherence tomography, extent of thinning in clock hours, grade of microdots, and stage of TMD were analyzed.

RESULTS

According to Süveges and Wang classification, the median stage of TMD was 2 (range, 2-3) and 2 (range, 2-6), respectively. Twelve (71%) of 17 eyes with clinical TMD showed corneal thinning at all clock hours. The median age at the time of examination was 70 years (range, 28-81), and the median time from diagnosis 8.8 years (range, 6.0-15.2). By IVCM, the epithelium, subepithelial nerve plexus, and endothelium were intact in all eyes. The anterior stroma showed bilateral hyperreflective dots in the central cornea beneath the subepithelial nerve plexus in all eyes, and larger patches were detected in the posterior stroma anterior to Descemet membrane; both were invisible by anterior segment optical coherence tomography. As compared with controls, the grade of anterior microdots increased faster with age before the age of 65, and that of posterior stromal patches was higher. Two patients additionally had bilateral hyperreflective needle-like deposits in the anterior and midstroma.

CONCLUSIONS

By IVCM, TMD is characterized regardless of clinical laterality by bilateral microdots in the central corneal stroma. They might be a supporting diagnostic criterion and alone could suggest subclinical disease.

Dystrophia Adiposa Corneae: An Out-of-the-Box Diagnosis

Dystrophia adiposa corneae is a degenerative corneal disorder characterised by fatty deposition, leading to corneal opacity and reduced visual acuity. We report a case of an Indian male in his early 40s with bilateral peripheral deep lipid deposition in the corneal stroma, beginning in an arcuate fashion and progressing to an annular-shaped structure. Furthermore, cholesterol crystals, as well as crystalline structures, were seen without any neovascularisation. We confirmed these findings on anterior segment optical coherence tomography (AS-OCT). We also noticed an increase in central corneal thickness (CCT), and on systemic workup, the patient was diagnosed with mild dyslipidaemia. This case highlights the need for an out-of-the-box diagnosis of a rare keratopathy, which can be vision-threatening and needs to be differentiated from its mimickers.

Inflammatory Cells and Lipid Deposits Detected by in Vivo Confocal Microscopy in Brimonidine Tartrate Ophthalmic Solution-Related Corneal Disorders: A Case Series

We reviewed the medical charts of five patients diagnosed with brimonidine tartrate (BT)-related corneal disorders. A fan-shaped corneal opacity was present in four patients and limbal corneal infiltrations were present in one patient. In vivo confocal microscopy revealed dendritic cells and lipid deposits in the fan-shaped opacity as well as neutrophils in limbal infiltrations. BT instillation was discontinued and topical administration of a corticosteroid was initiated for all patients. The limbal infiltrations improved after BT discontinuation. Conversely, the fan-shaped opacity remained in all affected patients. After a fan-shaped opacity has developed in a patient with a BT-related corneal disorder, the lesion is difficult to resolve. However, limbal infiltrations respond well to treatment. Therefore, BT should be discontinued and anti-inflammatory treatment initiated before a fan-shaped opacity forms.

Cogan syndrome: a case report and review of the literature

Cogan syndrome is a rare disease whose etiology is still undetermined. It typically affects men and women between the second and fourth decade of life. We report a case of Cogan syndrome with ocular and audio-vestibular involvement as a systemic manifestation in a 31-year-old woman.

Posterior corneoscleral limbus: Architecture, stem cells, and clinical implications

The limbus is a transition from the cornea to conjunctiva and sclera. In human eyes, this thin strip has a rich variation of tissue structures and composition, typifying a change from scleral irregularity and opacity to corneal regularity and transparency; a variation from richly vascularized conjunctiva and sclera to avascular cornea; the neural passage and drainage of aqueous humor. The limbal stroma is enriched with circular fibres running parallel to the corneal circumference, giving its unique role in absorbing small pressure changes to maintain corneal curvature and refractivity. It contains specific niches housing different types of stem cells for the corneal epithelium, stromal keratocytes, corneal endothelium, and trabecular meshwork. This truly reflects the important roles of the limbus in ocular physiology, and the limbal functionality is crucial for corneal health and the entire visual system. Since the anterior limbus containing epithelial structures and limbal epithelial stem cells has been extensively reviewed, this article is focused on the posterior limbus. We have discussed the structural organization and cellular components of the region beneath the limbal epithelium, the characteristics of stem cell types: namely corneal stromal stem cells, endothelial progenitors and trabecular meshwork stem cells, and recent advances leading to the emergence of potential cell therapy options to replenish their respective mature cell types and to correct defects causing corneal abnormalities. We have reviewed different clinical disorders associated with defects of the posterior limbus and summarized the available preclinical and clinical evidence about the developing topic of cell-based therapy for corneal disorders.

Lipid Keratopathy: Histopathology, Major Differential Diagnoses and The Importance of Clinical Correlation

Lipid keratopathy (LK) is a rare ophthalmological condition characterized by a progressive reduction in visual acuity caused by corneal opacification due to central lipid accumulation. LK is characterized by lipid deposits, cholesterol clefts, and neovascularization (NV) leading to disruption in corneal optical quality. LK classification includes a primary and secondary form which depend on pre-existing corneal or systemic disorders and the evidence of NV. Secondary LK is typically associated with a prior occurrence of herpetic infection, such as herpes zoster keratitis. Patients with LK usually present with progressive vision loss and dense cream-colored corneal opacification. Treatment modalities include conservative and surgical approaches focused on corneal NV elimination. When evaluating corneal lipidosis, it is crucial to consider a range of differential diagnoses, including corneal arcus, Schnyder corneal dystrophy, and other corneal deposit conditions. We report a case of a 62-year-old male with herpes zoster keratitis complicated with LK. He presented with painless progressive vision loss and corneal scarring, which raised suspicion about LK diagnosis. This paper emphasizes the importance of correlating clinical and histological findings for accurate LK diagnosis.

Clinical demographic characteristics and ocular Co-morbidities associated with Secondary lipid keratopathy at a tertiary care center

OBJECTIVE

To describe the demographics and clinical profile of Secondary Lipid Keratopathy in patients presenting to a multi-tier ophthalmology hospital network in India.

METHODS

This cross-sectional hospital-based study included 3,082,727 new patients presenting between August 2010 and December 2021. Patients with a clinical diagnosis of Secondary Lipid Keratopathy in at least one eye were included as cases. The data were collected using an electronic medical record system.

RESULTS

Overall, 389 (0.01%) patients were diagnosed with Secondary Lipid Keratopathy. Majority were males (53.5%) and had a unilateral affliction (82.8%). The most common age group at presentation was during the sixth decade of life with 76 (19.5%) patients. The overall prevalence was higher in patients from a lower socio-economic status (0.02%) presenting from the rural geography (0.01%) and in individuals related to agriculture work/ manual labor (0.02%). Of the 456 eyes, mild or no visual impairment (<20/70) was noted in 194 (42.5%) eyes followed by moderate visual impairment (>20/70 to 20/200) in 81 (17.8%) eyes. At presentation, the mean visual acuity was 0.96 ± 1.07 log MAR units. The most associated corneal condition was non-HSV corneal scar (36.8%), followed by spheroidal degeneration (19.7%) and HSV keratitis in (18.6%).

CONCLUSION

Secondary lipid keratopathy more commonly affected males presenting during the sixth decade of life. Most (42.5%) of the eyes had mild or no visual impairment. Corneal scar (non-HSV) was the most associated corneal condition in both unilateral and bilateral cases. HSV keratitis was the commonest corneal condition in those between 20 and 40 years, followed by those above 40 years.

Case report of interstitial keratitis in pregnancy

Purpose

To report an unusual case of interstitial keratitis and lipid keratopathy in a pregnant woman with unknown etiology and atypical clinical course.

Observations

A 15 weeks pregnant 32-year-old female daily soft contact lens wearer presented with 1 month of right eye redness and intermittent blurry vision. Slit lamp examination revealed sectoral interstitial keratitis with stromal neovascularization and opacification. No underlying ocular or systemic etiology was identified. The corneal changes were unresponsive to treatment with topical steroids and progressed over the ensuing months of her pregnancy. On continued follow up, the cornea demonstrated spontaneous partial regression of the opacification in the post-partum period.

Conclusions and importance

This case illustrates a possible rare manifestation of pregnancy physiology in the cornea. It also emphasizes the utility of close follow-up and conservative management in pregnant patients with idiopathic interstitial keratitis not only to avoid intervention during pregnancy but also because of the possibility of spontaneous improvement or resolution of the corneal changes.

Disseminated idiopathic lipid keratopathy in a normolipemic cat

OBJECTIVE

To report a case of idiopathic lipid keratopathy in a normolipemic cat.

ANIMAL STUDIED

A 10-year-old neutered female European domestic cat.

RESULTS

A cat was evaluated for bilateral white corneal deposits. Slit-lamp examination revealed multiple, well-defined, round, stromal, cream-colored deposits of different sizes associated with generalized superficial corneal vascularization. Blood lipids were normal, and no history of travel to tropical locations or ocular trauma was present. Topical betamethasone/gentamicin 0.1% suspension q 12 hours did not result in any improvement of clinical appearance after one week. Tomography following the initial therapy revealed dense, hyperreflective deposits with posterior shadowing in the anterior and mid stroma of both corneas. A four-week course of itraconazole 0.01% ophthalmic cream was prescribed q 12 hours with no improvement. Four months after the initial examination, a diagnostic superficial keratectomy and amniotic membrane implantation were performed. Histopathological analysis showed membrane bound vacuoles with infiltration of foamy macrophages suggesting a diagnosis of primary lipidosis. The post-surgical period was unremarkable, and ten days later, the patient was re-examined. Opacification from a corneal leukoma was observed in the excision site with mild fibrotic tissue. Two months post-keratectomy, no further changes were detected in the cornea, and the patient was managed only with topical lubricant.

CONCLUSIONS

To our knowledge, this is the first report of idiopathic corneal lipidosis in a cat and may be considered as a differential diagnosis of corneal disease in felines.

Bilateral Lipid Keratopathy in the Setting of Brimonidine Tartrate Use

Lipid keratopathy (LK) is a rare disease involving lipid deposition in the cornea resulting in corneal opacification. Primary LK can arise sporadically while secondary LK is seen in patients with a history of ocular trauma, medication exposure, infection, inflammation, or disorders resulting in derangements of lipid metabolism. Secondary LK is more common and occurs due to neovascularization. Use of precipitating medications should be considered in LK workup, particularly for patients in whom other etiologies have been ruled out. Brimonidine, an ocular hypotensive medication, can be associated with LK. We present a case of bilateral secondary LK in a patient with a history of prolonged brimonidine use, without additional contributing factors.

Radiofrequency diathermy as a treatment of lipid keratopathy in a radial keratotomy incision

Purpose

We report a case of lipid keratopathy in a radial keratotomy incision that was successfully managed with radiofrequency diathermy of the neovascular pedicle responsible for the lipid deposition.

Observations

No perioperative or postoperative complications were noted. Following the procedure, the lesion showed significant decrease in lipid deposits and opacification along with disappearance of the neovascular pedicle.

Conclusions and importance

Radiofrequency diathermy of neovascular pedicle may represent an effective and safe alternative treatment option for treating lipid keratopathy. This is a first ever report of lipid keratopathy inside a radial keratotomy incision that was successfully managed by radiofrequency diathermy.

•

We report a case of lipid keratopathy in a radial keratotomy incision.

•

We successfully managed the case with radiofrequency diathermy of the neovascular pedicle.

•

After treatment, the lesion showed regression of the opacification along with disappearance of the neovascular pedicle.

•

Radiofrequency diathermy may represent an effective and safe alternative treatment option for treating lipid keratopathy.

Corneal thinning following bevacizumab intrastromal injection for the treatment of idiopathic lipid keratopathy

Purpose

To describe the occurrence of corneal thinning in a patient following intrastromal injection of bevacizumab to treat lipid keratopathy.

Observations

A 36-year-old female presented with decreased vision in her right eye with central posterior corneal haze and underwent a treatment regimen including artificial tears, cyclosporine 0.05% drops, prednisolone 1% and oral Valacyclovir 1g with no improvement. Neovascularization was noted at 18 months follow up and treated with intrastromal bevacizumab injections at 24 months. The feeder vessel was attenuated at 3- and 6-months post-injection, but tomography indicated sustained thinning and flattening of the cornea at the injection site contributing to the development of irregular astigmatism.

Conclusions and Importance

Corneal thinning is an uncommon potential side effect of intrastromal bevacizumab injection that may affect postoperative visual acuity.

Initial outcomes of mitomycin intravascular chemoembolization (MICE) for corneal neovascularization

Purpose

To report on the preliminary outcomes of mitomycin C (MMC) intravascular chemoembolization (MICE) for corneal neovascularization (NV).

Methods

This is a retrospective case series of three consecutive eyes that underwent MICE for progressive corneal NV with sight threatening lipid keratopathy. A 1.0 cc syringe was partially filled with MMC (0.4 mg/mL) and attached to a 33-gauge needle used to cannulate the vessels. The MMC (0.01–0.05 ml) was injected with enough retrograde hydrostatic force to fill efferent and afferent vessels. Follow-up ranged from 4 months to 1 year.

Results

Three eyes of three patients aged 59, 73 and 33 years were included. There were no intraoperative or postoperative complications associated with the MICE procedure. Patient 1 presented with progressive corneal NV and lipid keratopathy secondary to herpes zoster ophthalmicus (HZO) and a best-corrected spectacle visual acuity (BSCVA) of 20/100 Snellen. At one-year post-MICE, there was no recurrence (BSCVA was 20/20 Snellen). Patient 2 presented with idiopathic lipid keratopathy (BSCVA 20/50 Snellen). At four months post-MICE, there were no signs of recurrence (BSCVA 20/20 Snellen). Patient 3 presented with corneal NV and lipid keratopathy secondary to HZO (BSCVA 20/30 Snellen). At four months following two MICE treatments, resolution of the lipid keratopathy was noted (BSCVA 20/20 Snellen).

Conclusions

Preliminary findings suggest that MICE may be an additional modality for treating progressive corneal NV with lipid keratopathy. Larger comparative studies with longer follow-up are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10792-022-02240-6.