Band keratopathy due to hyperparathyroidism

The effect of EDTA solution on corneal endothelial cells in rabbits

Corneal disease threatens vision globally. Among corneal diseases, calcific band keratopathy has severe effects on vision owing to its unique location. Currently, ethylene diamine tetraacetic acid (EDTA) chelation remains the most important treatment. However, only the safety of low-dose topical EDTA eye drops is well established in humans. Therefore, the purpose of this study was to determine the safe dose range of EDTA for calcific band keratopathy surgery and its toxic effects on rabbit eyes. Rabbits were administered different doses of EDTA solutions (0.50, 0.20, 0.10, 0.05, and 0.01 M) for twenty minutes. In day seven, the rabbits were euthanized and pathological examination was performed for cornea. We found severe corneal edema in 0.50 M group, while milder edema in lower-concentration treated groups. Followed by corneal thickness measurement, the measured values increase to the peak in post-operative three day (0.20 M group) or one day (lower-concentration groups), then decreased. Groups comparison shown significant difference between BSS control group and higher concentration groups (0.20 M and 0.10 M) (P < 0.001) in observation period, but no significance was observed between low concentration and control group in the day seven after surgery (P > 0.05). Confocal microscopy examination suggested, the number of corneal endothelial cells significantly decreased from 3428.6 ± 180.3 cells/mm² to 2808 ± 80.6 cells/mm² in the 0.50 M group, while the lower-concentration groups showed lesser toxic effects on corneal endothelial cells. Finally, our histological examination demonstrated inflammation in each experimental group and dose-dependent, compared with control group. Our study found 0.05 M and 0.01 M EDTA solutions had no obvious toxic effect on the corneal endothelium compared with higher concentration. However, further study of EDTA side effect by clinical trials, and therapeutic effect observation with different concentration are necessary.

Systemic diseases and the cornea

There is a number of systemic diseases affecting the cornea. These include endocrine disorders (diabetes, Graves' disease, Addison's disease, hyperparathyroidism), infections with viruses (SARS-CoV-2, herpes simplex, varicella zoster, HTLV-1, Epstein-Barr virus) and bacteria (tuberculosis, syphilis and Pseudomonas aeruginosa), autoimmune and inflammatory diseases (rheumatoid arthritis, Sjögren's syndrome, lupus erythematosus, gout, atopic and vernal keratoconjunctivitis, multiple sclerosis, granulomatosis with polyangiitis, sarcoidosis, Cogan's syndrome, immunobullous diseases), corneal deposit disorders (Wilson's disease, cystinosis, Fabry disease, Meretoja's syndrome, mucopolysaccharidosis, hyperlipoproteinemia), and genetic disorders (aniridia, Ehlers-Danlos syndromes, Marfan syndrome). Corneal manifestations often provide an insight to underlying systemic diseases and can act as the first indicator of an undiagnosed systemic condition. Routine eye exams can bring attention to potentially life-threatening illnesses. In this review, we provide a fairly detailed overview of the pathologic changes in the cornea described in various systemic diseases and also discuss underlying molecular mechanisms, as well as current and emerging treatments.

"Off-the-Shelf" K2-EDTA for Calcific Band Keratopathy

PURPOSE

To explore the effectiveness of "off-the-shelf" dipotassium-ethylenediaminetetraacetic acid (K2-EDTA) as an alternative to sodium EDTA as chelation therapy in removal of calcific band keratopathy (CBK).

METHODS

This study was a retrospective case series involving 4 patients with CBK who underwent superficial keratectomy and subsequent chelation therapy with K2-EDTA in a single center (Coastal Eye Clinic) by the same surgeon. Visual acuity and symptomatic relief were the main outcomes measured in our study.

RESULTS

All 4 participants in this study were female with an average age of 80.3 years. Three of the patients with reasonable baseline visual acuity experienced improved visual acuity at 1 month. The other patient with multiple ocular comorbidities and severely reduced visual potential reported symptomatic pain relief at 1-month follow-up after the intervention.

CONCLUSIONS

K2-EDTA seems to be an effective alternative to disodium EDTA in its ability to clear calcific plaques and restore visual function. Because of the logistical difficulties associated with acquiring disodium EDTA, and the relative abundance of K2-EDTA in health-care facilities, we believe that our findings warrant further investigation into its use as a more accessible and cost-effective chelating agent in CBK.

Two percent ethylenediaminetetraacetic acid chelation treatment for band-shaped keratopathy, without blunt scratching after removal of the corneal epithelium

Background

The purpose of this study was to assess the effectiveness of 2% ethylenediaminetetraacetic acid (EDTA) for the treatment of band-shaped keratopathy.

Methods

We studied 24 eyes of 16 patients with band-shaped keratopathy who underwent EDTA chelation treatment from April 1, 2011 to December 31, 2012. We compared preoperative and 1 month postoperative logarithm of the minimum angle of resolution (logMAR) best corrected visual acuity, intraocular pressure, and corneal curvature radius (K1, horizontal meridian; K2, vertical meridian; Km, average of K1 and K2). The Mann-Whitney U-test was used to determine the significance of differences.

Results

There was a significant difference in preoperative and postoperative logMAR best corrected visual acuity (P=0.01). There were no significant differences in preoperative and postoperative intraocular pressure (P=0.24) or corneal curvature radius (K1, P=0.54; K2, P=0.49; Km, P=0.45).

Conclusion

After 2% EDTA chelation treatment, post-operative logMAR best corrected visual acuity improved significantly. Moreover, since there was no significant difference in corneal curvature radius, there was little influence on corneal surface form. We believe that the results of our 2% EDTA chelation treatment were comparable with results obtained with 3.75% EDTA chelation treatment in previous reports. Two percent EDTA chelation is an effective treatment for band-shaped keratopathy and a useful method for any institution.

Multiple calcified deposits along the eyelid margins secondary to chronic renal failure and hyperparathyroidism

BACKGROUND

Corneal and conjunctival calcification have been associated with chronic renal failure and hyperparathyroidism. Corneal alterations include band keratopathy and/or limbal involvement similar to limbal girdle of Vogt. Conjunctival lesions resemble pingueculae. Lid lesions, which include calcified deposits adjacent to the meibomian gland orifices, are much less common.

CASE REPORT

A 52-year-old woman came to SUNY State College of Optometry clinic with a medical history of gestational hypertension, which led to chronic kidney failure and secondary hyperparathyroidism. Slit-lamp examination revealed multiple small, white, round calcium deposits, which were found just posterior to the Meibomian gland orifices, along the superior and inferior lid margins.

CONCLUSION

Ocular calcification has been observed in patients with certain systemic diseases such as chronic renal failure, hyperparathyroidism, hypophosphonemia, sarcoidosis, hypervitaminosis D, and metastatic neoplasia. We present the third report of eyelid calcification associated with a systemic disease.

EDTA chelation for calcific band keratopathy: results and long-term follow-up

PURPOSE

To determine the etiologies and management of calcific band keratopathy (CBK), and assess the results and long-term follow-up after ethylenediamine-tetraacetic acid (EDTA) chelation.

DESIGN

Retrospective interventional case series.

METHODS

Two hundred thirty patients with clinically significant CBK were included from January 1996 to July 2002. Among these, 54 patients (65 eyes) underwent EDTA chelation. Outcome measures included symptomatic relief, visual improvement, and recurrences. The improvement or worsening of the number of lines of Snellen best-corrected visual acuity was determined at 1 month and at last follow-up visit.

RESULTS

The most common causes of CBK were chronic corneal edema in 80 eyes (28%) and idiopathic in 74 eyes (25.9%). The mean follow-up time after EDTA chelation was 36.6 months (range, 1 month to 29.6 years). Forty-four of 45 patients (98%) reported partial or complete symptomatic relief. Seventeen eyes (33.3%) improved 2 or more lines at 1 month and 18 eyes (35.2%) at last follow-up visit (P =.0001). In patients with an initial visual acuity between 20/50 and 20/400, 15 eyes (47%) improved 2 or more lines at 1 month and 16 eyes (50%) at last follow-up visit. Ten of 56 eyes (17.8%) had a recurrence at a mean time of 17.7 years (range, 1 month to 26 years). The highest number of recurrences was in three of five eyes with uveitis (60%; P =.03).

CONCLUSION

Chelation with EDTA is an effective treatment of CBK. Visual acuity improves most in eyes with acuity between 20/50 and 20/400. This treatment can be used as the initial surgical intervention after conservative measures fail.