Management of band keratopathy with excimer phototherapeutic keratectomy: visual, refractive, and symptomatic outcome

Excimer Laser Phototherapeutic Keratectomy for Anterior Corneal Opacification After Descemet Membrane Endothelial Keratoplasty

PURPOSE

The aim of this study was to assess the long-term outcome of excimer laser phototherapeutic keratectomy (PTK) for treating remaining anterior corneal opacities after Descemet membrane endothelial keratoplasty (DMEK).

METHODS

This cohort study analyzed 67 eyes of 66 patients undergoing PTK in addition to and after DMEK between 2012 and 2021 at the Department of Ophthalmology, University of Cologne. Patients who were treated by PTK after previous DMEK on the same eye were included. The outcome parameters were best corrected visual acuity (BCVA), changes in refraction, endothelial cell density, corneal densitometry, central corneal thickness, and total corneal higher order aberrations. Patients with visual limitations in addition to anterior opacification were analyzed separately for their visual outcome. Eyes with severe visual limitations that have a very limited visual potential were excluded from the study. In addition, patients with not at least 1 postoperative follow-up examination were excluded from the study.

RESULTS

In this study, 67 eyes of 66 patients met all inclusion criteria. The median follow-up period was 13.1 (quartiles: 4.1; 30.7; interquartile range 26.6) months. The mean (±SD) BCVA improved from (logarithm of the minimum angle of resolution) 0.54 (±0.32) to 0.38 (±0.27) at the first postoperative visit ( P < 0.001) and remained significantly improved at all follow-up examinations compared with preoperative BCVA. Refraction and endothelial cell density did not change significantly after PTK. There was a significant decrease in corneal backscatter in the anterior corneal layer ( P < 0.001), and the total higher order aberration ( P = 0.02) and central corneal thickness were significantly reduced at the most recent postoperative visit ( P < 0.001). No immune reactions were observed.

CONCLUSIONS

Excimer laser PTK after DMEK for persisting anterior corneal opacities has the potential to significantly improve patients' vision without affecting refractive parameters or endothelial cell density.

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.

Case Report: Phototherapeutic Keratectomy for Band Keratopathy Secondary to Chemo-Laser-Cryotherapy for Retinoblastoma

Purpose: To report the clinical outcomes of phototherapeutic keratectomy (PTK) for pediatric band keratopathy after treatment for retinoblastoma.

Methods: A 5-year-old boy presented with a 2-year history of poor visual acuity and a horizontal gray-white band across the central cornea in the right eye. He was diagnosed with band keratopathy after chemo-laser-cryotherapy for retinoblastoma. The band keratopathy was treated via PTK using the Mel-90 excimer laser with an optical treatment zone of 7.0 mm and ablation depth of 120 μm. The patient was followed at 1 week and 3 months postoperatively.

Results: Surgery and postoperative follow-up were uneventful. At the 3-month follow-up, the uncorrected distant visual acuity of the right eye improved to 20/125, and the corrected distance visual acuity improved to 20/70 with a refraction of +10.00 D/−2.50 DC × 15. The clarity of the ablated area was evidently improved. The central corneal thickness decreases from 612 to 584 μm. The optical coherence tomography showed the thin band of hyperreflectivity in the ablated area disappeared, corneal transparency improved and the corneal surface smoothened.

Conclusions: PTK is a safe and effective procedure to treat band keratopathy following treatment of retinoblastoma in children. Early intervention can reduce the risk of developing deprivation amblyopia.

Phototherapeutic keratectomy: Indications, methods and decision making

Phototherapeutic keratectomy (PTK) involves treating anterior corneal lesions by superficial corneal ablation using an excimer laser (193 nm). Some of the commonly treated conditions include recurrent corneal erosions (RCE), corneal dystrophies, spheroidal degeneration, keratoconus, and corneal scars. We discuss various techniques of PTK including large area PTK, focal PTK, and multifocal PTK and alternatives to PTK. Masking agents like hyaluronate, methylcellulose, and dextran are recommended to help achieve a better outcome when ablating irregular corneal surfaces. Antifibrotic agents like mitomycin C reduce the chances of recurrence of the disease, apart from minimizing the postoperative scarring. Some of the complications include induced hyperopia and irregular astigmatism, haze, recurrence, and corneal thinning. However, earlier postoperative recovery, possibility of a repeat procedure, and ability to control the depth of ablation make PTK a promising, minimally invasive alternative to keratoplasty in cases with anterior corneal pathologies.

Excimer laser-assisted phototherapeutic keratectomies combined to EDTA chelation for the treatment of calcific band keratopathy

INTRODUCTION

Calcific band keratopathy (CBK) is a relatively common chronic corneal degeneration and various forms of treatment are mentioned in the literature.

CASES DESCRIPTION

Two patients (89 and 37 yo, respectively) affected by diffuse long-standing CBK in one eye and complaining of ocular pain, foreign body sensation and decreased visual acuity are reported. An ethylenediaminetetraacetic acid (EDTA) application on the ocular surface was performed associated with a customized no-touch transepithelial phototherapeutic corneal remodeling in one patient and a standard phototherapeutic keratectomy (PTK) in the second patient. Corneal transparency progressively improved in both cases since the early follow-up visits and the cornea became clear 2 weeks after surgery. In both cases, a significant reduction of ocular discomfort was reported.

CONCLUSIONS

Combining EDTA chelation and excimer laser-assisted PTK represents an useful treatment of band keratopathy even in challenging cases and may help regularize corneal surface and improve corneal clarity.

Transepithelial phototherapeutic keratectomy for the treatment of severe band keratopathy

PURPOSE

The goal of this study was to investigate the clinical outcomes of transepithelial phototherapeutic keratectomy (transepithelial PTK) for the treatment of severe band keratopathy.

METHODS

A consecutive series of severe band keratopathy cases treated with transepithelial PTK were retrospectively analysed between January 2018 and December 2019. Severe band keratopathy was defined as corneal plaques apparent in the obscuration of iris details. Patients' medical histories, preoperative and postoperative symptomatic relief, cosmesis, best-corrected visual acuity (BCVA), complications, and recurrences were analysed.

RESULTS

Seventeen eyes of 16 patients were included in the study, with a mean follow-up of 9.8 ± 5.2 months (3 to 19 months). The mean age of the patients was 15.8 ± 10.2 years (8 to 46 years). Symptoms were significantly or completely relieved in all patients (100%). The results of cosmesis were good in 14 eyes (82.4%). Among those eyes that had BCVA of hand motion or better preoperatively, seven eyes (100%) showed an improvement in BCVA postoperatively. There were no complications or recurrences associated with transepithelial PTK treatment during the follow-up period.

CONCLUSIONS

Transepithelial PTK is an effective treatment to eliminate corneal opacity and alleviate symptoms in patients with severe band keratopathy. This technique could be an alternative approach to managing severe band keratopathy.

"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.

Risk of Band Keratopathy in Patients with End-Stage Renal Disease

This study is a retrospective, nationwide, matched cohort study to investigate the risk of band keratopathy following end-stage renal disease (ESRD). The study cohort included 94,039 ESRD on-dialysis patients identified by the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM), code 585 and registered between January 2000 to December 2009 at the Taiwan National Health Insurance Research Database. An age- and sex-matched control group comprised 94,039 patients selected from the Taiwan Longitudinal Health Insurance Database 2000. Information for each patient was collected from the index date until December 2011. In total, 230 ESRD patients and 26 controls had band keratopathy (P < 0.0001) during the follow-up period, indicating a significantly elevated risk of band keratopathy in the ESRD patients compared with controls (incidence rate ratio = 12.21, 95% confidence interval [CI] = 8.14-18.32). After adjustment for potential confounders including sarcoidosis, hyperparathyroidism, iridocyclitis, and phthisis bulbi, ESRD patients were 11.56 times more likely to develop band keratopathy in the full cohort (adjusted HR = 11.56, 95% CI = 7.70-17.35). In conclusion, ESRD increases the risk of band keratopathy. Close interdisciplinary collaboration between nephrologists and ophthalmologists is important to deal with band keratopathy following ESRD and prevent visual acuity impairments.

Uveitic band keratopathy: child and adult

Background

Calcified band keratopathy is a chronic degenerative disease characterized by the deposition of gray to white opacity in superficial layers of the cornea that typically develops over months or years. It is associated with a variety of conditions, including chronic uveitis.

Purpose

The objective of this study is to assess visual acuity and corneal changes in patients with band keratopathy secondary to uveitis who underwent phototherapeutic keratectomy (PTK).

Setting

The place where this study was performed was in the Department of Ophthalmology and Visual Sciences, Federal University of Sao Paulo.

Design

This is a retrospective study.

Methods

Patients with uveitic band keratopathy were submitted to PTK. The PTK was performed using Allegreto Wave EX500, with the ablation area of 6 mm.

Results

Twelve patients (13 eyes) diagnosed with band keratopathy secondary to chronic uveitis were analyzed. Of the 12 patients, 8 patients were female (66 %), aged 22 years (7–53 years). From the 12 patients (13 eyes) evaluated in this study, only one patient (one eye) did not have visual improvement, due to epithelial deposits 2 weeks after PTK, and all the others benefited with the procedure. In the children group, all eyes had visual improvement, and quantitatively speaking, the children had a more significant improvement than adults.

Conclusions

PTK is a safe and effective procedure even for children. However, the improvement in visual acuity was restricted due to other ocular changes secondary to uveitis, such as cataract and retinal changes, or even the corneal irregularity.

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.

Techniques, indications and complications of corneal debridement

The cornea is the most exposed surface of the eye and, as such, is vulnerable to external trauma and the risk of infection. Many corneal diseases alter shape, surface, and transparency and thus result in reduced vision. The external position of the cornea, however, lends itself to diagnostic and therapeutic maneuvers that are commonly performed and readily done in the clinic. More sophisticated techniques require the use of complex equipment such as excimer and femtosecond laser. Complications that develop from poor healing and/or secondary infection are best avoided with appropriate technique, antisepsis, and modification of wound healing. We review corneal debridement in the management of corneal disease.

Phototherapeutic keratectomy

Phototherapeutic keratectomy (PTK) is done regularly for anterior corneal diseases such as corneal dystrophies, corneal degenerations, scars, and band-shaped keratopathy. The various indications include both therapeutic and visual. The aim of this article is to discuss the therapeutic indications for PTK, the specific technique pertaining to a specific etiology, the various other procedures like amniotic membrane graft combined with PTK or PTK being done for recurrences in the grafts, and PTK done before cataract surgery when the anterior corneal pathology coexists with the cataract. Post PTK management such as healing of an epithelial defect, use of steroids in the post PTK period, recurrences of primary disease pathology, and infections, will be discussed. Methods of literature search: A Medline search was carried out for articles in the English language, with the keywords, phototherapeutic keratectomy, band-shaped keratopathy, spheroidal degeneration, scars, bullous keratopathy, and corneal dystrophy. The relevant references are mentioned here.

Excimer laser phototherapeutic keratectomy for the treatment of silicone oil-induced band-shaped keratopathy

PURPOSE

To study the efficacy of excimer laser phototherapeutic keratectomy (PTK) for the treatment of band-shaped keratopathy (BSK).

METHODS

A retrospective analysis of case records of 20 eyes of 20 patients with silicone oil-induced BSK and significant media haze that underwent PTK was conducted. Improvement in corneal clarity and best-corrected visual acuity (BCVA) was assessed at 6 weeks postoperatively.

RESULTS

The mean ablation depth was 62.63±23.82 μm (range 25 to 100 μm). Postoperative course was uneventful, and the mean time for healing of the epithelial defect was 4.25±2.43 days. All the eyes showed significant improvement in corneal clarity at 6 weeks postoperatively. The mean score of corneal clarity increased from 1.15±0.74 preoperatively to 3.35±0.49 at 6 weeks postoperatively (P<0.001). At postoperative 6 weeks, 90% (18 eyes) showed an improvement in BCVA of 2 or more lines, whereas the BCVA remained unchanged in two eyes (10%). There was a hyperopic shift postoperatively with a mean shift of spherical equivalent of 2.23±2.08 D. At the end of the last follow-up (mean: 16.75±4.2 months; range 11-24 months), two eyes with silicone oil in the vitreous chamber and with inferior peripheral and shallow retinal detachment showed recurrence of BSK for which retreatment with PTK was given.

CONCLUSIONS

Phototherapeutic keratectomy is an effective option for the treatment of silicone oil-induced BSK with significant improvement in corneal clarity. However, the gain in visual acuity depends on the coincident posterior segment pathologic condition. Further, in eyes with retained silicone oil, there is a risk of recurrence of BSK for which retreatment may be required.

Successful treatment of superficial corneal irregularity by lamellar keratectomy using the femtosecond laser

The authors report successful vision restoration after cataract surgery using a femtosecond laser in a patient with superficial corneal irregularity. A 62-year-old man with corneal irregularity and a cataract in the left eye was referred for treatment. The superficial corneal opacity causing the irregularity was mainly located within the superficial anterior cornea. To acquire a stable keratometric value, which is important for accurate calculation of intraocular lens power, lamellar keratectomy using a femtosecond laser (IntraLase; AMO, Irvine, CA) was performed to smooth the cornea surface. Postoperatively, corneal smoothness was restored and a stable keratometric value was acquired. Vision was improved with the expected refraction after cataract surgery. The femtosecond laser may be an effective surgical tool for patients with superficial corneal irregularity and cataracts.

Combined ethylenediaminetetraacetic acid chelation, phototherapeutic keratectomy and amniotic membrane transplantation for treatment of band keratopathy

PURPOSE

The objective of this study is to evaluate the therapeutic efficacy of ethylenediaminetetraacetic acid (EDTA) chelation and excimer laser phototherapeutic keratectomy (PTK) combined with amniotic membrane transplantation (AMT) for the treatment of band keratopathy (BK).

METHODS

Eleven eyes in ten patients with BK received combined PTK (ablation zone of central 7.0-7.5 mm, depth of 50 microm), EDTA chelation (0.05 M, 3 minutes), and amniotic membrane transplantation using fibrin glue. Preand postoperative best corrected visual acuities, symptom changes, reepithelialization time, cosmesis, recurrence, and complications were analyzed.

RESULTS

Visual acuity improved in three eyes (27.3%) and did not change in eight eyes (72.7%). Symptoms improved in all patients, and the mean reepithelialization time was 10.6+/-5.3 days. The cosmetic results were good in eight eyes (72.7%) and were fair in three eyes (27.3%). During the mean follow-up period of 11.4+/-6.1 months (range, 6 to 23 months), no postoperative complications or recurrences were observed.

CONCLUSIONS

The combination of EDTA chelation, PTK, and AMT is safe and effective for the treatment of band keratopathy.

Amniotic membrane transplant with superficial keratectomy in superficial corneal degenerations: efficacy in a rural population of north India

Aim:

To evaluate the applicability and efficacy of superficial keratectomy with transplantation of preserved amniotic membrane in superficial corneal degenerations in a rural population of Northern India in terms of visual improvement and surface regularization.

Settings:

Peripheral referral center in rural north India.

Materials and Methods:

This was a prospective non-comparative interventional case series where 24 eyes of 20 farmers from peripheral rural areas (M:F = 19:1) with visually significant superficial degenerative disorders (15 eyes with climatic droplet keratopathy one of which was associated with Salzmann nodular degeneration and nine eyes with band-shaped keratopathy) were subjected to amniotic membrane transplantation (single or multiple layer) combined with superficial keratectomy. Subjective and objective outcomes after surgery were evaluated and analyzed and statistical significance of the outcomes in various disorders was evaluated.

Results:

Eighty-eight per cent (21 eyes) had symptomatic relief from distressing preoperative symptoms while postoperative visual improvement by two or more lines was achieved in 23 eyes (96%) over a mean follow-up period of 26.8 ± 10.2 months. The surface irregularity present preoperatively was relieved in 23 cases while postoperative decline of vision with visually significant scarring was seen in one case (4%), which was labeled as failure.

Conclusions:

Amniotic membrane transplant with superficial keratectomy helped achieve subjective comfort, visual rehabilitation and clinical regularization of the corneal surface in superficial corneal degenerations during the mean followup of 26.8 ± 10.2 months in rural setups.

Indications and outcomes of phototherapeutic keratectomy in the developing world

PURPOSE

To analyze the indications and outcomes of phototherapeutic keratectomy (PTK) in the developing world.

METHODS

In this retrospective study, the records of 203 consecutive eyes of 191 patients who had undergone PTK at a tertiary eye care center were evaluated. The parameters assessed were indications of PTK, demographic features, best spectacle-corrected visual acuity (BSCVA), and pachymetry. PTK was done by using a 193-nm Ar-F Excimer laser (Chiron Technolas Keracor 217 C) in a 6-mm optic zone. Patients were followed up for 6 months.

RESULTS

The most common indication of PTK was symptomatic bullous keratopathy (103 eyes). The patients were divided into 2 groups: those with bullous keratopathy (PTK BK) and those with superficial corneal pathologies (PTK CS). In the PTK CS group, the most common indications were Salzmann nodular degeneration (n = 27) and spheroidal degeneration (n = 22). BSCVA improved from 20/222 (0.09) to 20/86 (0.23) in the PTK CS group and 20/384 (0.05) to 20/202 (0.09) in the PTK BK group (P < 0.0001 in both groups). There was a significant decrease in the number of patients with severe symptoms in the PTK-BK (P < 0.0001) and PTK-CS (P = 0.017) groups. The change in BSCVA was significantly related to both pre-PTK BSCVA and pachymetry in PTK-BK.

CONCLUSIONS

PTK is an efficacious treatment modality for symptomatic relief and visual gain in cases with superficial corneal involvement and bullous keratopathy.

Phototherapeutic Keratectomy in Children

PURPOSE

Children with dense superficial opacities of the cornea are at risk for developing amblyopia. This study evaluated the efficacy of phototherapeutic keratectomy (PTK) in severe cases of anterior stromal scarring.

METHODS

Five eyes of five patients, aged 6 to 8 years, were included. Three children suffered from uveitis-associated band keratopathy, one child had anterior corneal stromal scarring due to viral infection, and one child had anterior basement membrane dystrophy. Phototherapeutic keratectomy was performed under general anesthesia using the 200 Hz ALLEGRETTO excimer laser. Optical treatment zone was 7.0 mm (one eye) and 8.0 mm (four eyes), and ablation depths were between 20 and 100 microm. Postoperative treatment consisted of bandage soft contact lens, topical preservative-free antibiotics, steroids, and artificial tears. Part-time occlusion therapy was continued, as prior to PTK. Because of the small cohort, statistical evaluation was not performed.

RESULTS

Mean follow-up was 23.4 +/- 13.7 months (range: 10 to 41 months). Surgery and postoperative follow-up were uneventful, and no signs of infection or haze were noted. Preoperative best spectacle-corrected visual acuity was 0.4 to 3.0 logMAR (mean: 1.22 +/- 1.07 logMAR). Best spectacle-corrected visual acuity improved in four eyes and stabilized in one eye due to uveitis recurrence (mean 0.64 +/- 0.65 logMAR). Mean preoperative keratometric values changed from 45.60 +/- 0.90 to 44.90 +/- 3.00 diopters postoperatively.

CONCLUSIONS

Dense superficial corneal opacity in children may be successfully treated with PTK. Phototherapeutic keratectomy was performed to increase corneal transparency and corneal surface smoothing thereby avoiding amblyopia.

Phototherapeutische Keratektomie

Phototherapeutic keratectomy (PTK) involves the removal of corneal tissue with an excimer laser for therapeutic and/or functional purposes. In contrast to photorefractive keratectomy, a change in manifest refraction is not the primary goal of the treatment. The main indications are poor epithelial adherence, corneal opacities or an irregular corneal surface, as well as combinations of these. We describe the basic techniques, such as large area and focal PTK and provide recommendations on use of different masking agents. Numerous well established and rare clinical examples are described in terms of achievable PTK results.

Multistage approach to uveitic cataract management in children

Phototherapeutic keratectomy, cataract extraction and hydrophobic acrylic lens implantation, Nd:YAG laser capsulotomy, glaucoma valve implantation, and intravitreal steroid injections resulted in substantial visual improvement in three eyes of two children with complicated cataract due to severe uveitis. At follow-up of 6 months to 4 years, the children had clear corneas and normal intraocular pressures.