|Year : 2018 | Volume
| Issue : 4 | Page : 215-218
Experience with keratoprosthesis at a tertiary eye care center: A report from North-East India
Saurabh Deshmukh1, Jnanankar Medhi2, Balmukund Agarwal2, Prafulla Sarma3, Krati Gupta1
1 Department of Ophthalmology, Sri Sankaradeva Nethralaya, Guwahati, Assam, India
2 Department of Cornea, Sri Sankaradeva Nethralaya, Guwahati, Assam, India
3 Department of Glaucoma, Sri Sankaradeva Nethralaya, Guwahati, Assam, India
|Date of Web Publication||19-Feb-2019|
Dr. Krati Gupta
Sri Sankaradeva Nethralaya, Beltola, Guwahati - 781 028, Assam
Source of Support: None, Conflict of Interest: None
Aim: To evaluate the preservation of visual acuity (VA) and the development of complications after keratoprosthesis (KPro) implantation (Boston KPro and Auro KPro) over a long follow-up period at a tertiary eye center in North-East India. Materials and Methods: This was a single-center retrospective case series. The records of all patients who underwent KPro implantation between March 2013 and August 2017 were analyzed. The preoperative characteristics, postoperative outcomes, complications, its management, and retention rates were reviewed. Results: Ten cases were included in the study. Preoperative VA ranged from counting finger close to face to hand movement close to face. The cause for KPro implantation included multiple graft failures (5 eyes, 50%), chemical injury (3 eyes, 30%), and Stevens–Johnson syndrome (2 eyes, 20%). Mean follow-up duration was 26.9 months (range, 12–54 months). At 1-month follow-up, eight patients had a vision ≥6/60 (80%). At 1-year follow-up, eight patients had a VA ≥6/24. Glaucoma was newly diagnosed in three eyes (30%); progression was noted in one eye (10%). Glaucoma drainage device was implanted in one eye (10%). Retroprosthetic membrane formed in seven eyes (70%) and one eye (10%) underwent KPro replacement. The initial KPro was retained in nine eyes (90%). Conclusions: KPro is an effective and a viable option for treating end-stage corneal diseases for salvaging vision. A significant number of patients lose vision following KPro implantation due to glaucoma and corneal melts. Our study reiterates the importance of regular and long-term follow-up and a comprehensive team approach for management of postoperative complications.
Keywords: Auro keratoprosthesis, Boston keratoprosthesis, graft failure, penetrating keratoplasty, Stevens–Johnson syndrome
|How to cite this article:|
Deshmukh S, Medhi J, Agarwal B, Sarma P, Gupta K. Experience with keratoprosthesis at a tertiary eye care center: A report from North-East India. TNOA J Ophthalmic Sci Res 2018;56:215-8
|How to cite this URL:|
Deshmukh S, Medhi J, Agarwal B, Sarma P, Gupta K. Experience with keratoprosthesis at a tertiary eye care center: A report from North-East India. TNOA J Ophthalmic Sci Res [serial online] 2018 [cited 2019 Dec 11];56:215-8. Available from: http://www.tnoajosr.com/text.asp?2018/56/4/215/252495
| Introduction|| |
Blindness is one of the major health problems in developing countries like India. According to the World Health Organization, among the major causes of vision loss in the developing countries today, corneal blindness ranks after cataract and glaucoma. As per the National Programme for Control of Blindness, the major causes of blindness in India are cataract, refractive error, glaucoma followed by corneal blindness. According to its estimate, every year, there is addition of 25,000–30,000 corneal blindness cases in the country. It is likely that the number of people with unilateral corneal blindness will increase to 10.6 million by 2020 in India.
Keratoprosthesis (KPro) implantation is the treatment of choice in cases of corneal blindness who cannot be treated successfully with corneal transplant procedures due to the presence of risk factors which predispose them to graft failure, such as extensive corneal vascularization, severe chemical injury, ocular surface disorder, Stevens–Johnson syndrome, multiple failed grafts, and other autoimmune disorders., The commonly used models are the Boston Type 1 KPro (BKPro) developed by Dohlman et al. and the Auro KPro (AKPro). BKPro is less commonly used because of its high cost and difficulty in obtaining in developing countries like India. AKPro by Aurolab, Madurai, India, is based on the design of the BKPro and is available for $100 in India, making it a more sustainable option.
The purpose of this study was to document our experience and challenges faced in the first 10 cases of a new KPro surgeon at a tertiary eye care center in Northeast India in terms of surgical outcomes, retention rate, postoperative complications, and their management over a long period of follow-up. This case series will also help analyze the results seen in this cohort with that of the other parts of India because this is the only institute providing the facility of KPro in the entire northeastern region.
| Materials and Methods|| |
The medical records of 10 eyes of 10 patients who underwent KPro implantation between March 2013 and August 2017 were retrospectively analyzed after obtaining permission from the institutional review board. All the patients underwent detailed ophthalmic evaluation, starting with elaborate history-taking, visual acuity (VA) testing, slit-lamp biomicroscopic examination, and assessment of tear production using the Schirmer's test. Assessment of the lids includes the status of the lid margins, lid closure, and symblepharon. Intraocular pressure measurement was performed using Tono-Pen or digital measurement in case of scarred corneas. Indirect ophthalmoscopic fundus examination was also done when possible. Ultrasound B-scan was done for the evaluation of posterior segment. Axial length measurement was done to determine the refractive power of the KPro to be implanted. Aphakic KPro was used in all cases. All the patients underwent vision testing, slit-lamp biomicroscopic examination, and fundus examination at all visits.
Aphakic KPro was used for all eyes. BKPro was obtained from the Massachusetts Eye and Ear Infirmary (Boston, MA, USA). The AKPro was obtained from Aurolab, Madurai, India. The details about both the devices and surgical methods used have been described in detail., Under either local anesthesia or general anesthesia. All the surgeries were performed by a single experienced surgeon (J. M.). The donor corneas were preserved in the Cornisol preservative media (Aurolab, India). Postoperatively, the patients were started on topical moxifloxacin 0.5% 4 times a day for a month. A biweekly tapering dose of topical steroids eye drops started 6 times per day and finally continued 2 times a day along with lubricating eye drops. A cycloplegic drop 2 times a day was advised to all patients for the first 1 month. A bandage contact lens was applied at the end of the surgery in all cases. It was replaced every 4–6 weeks and was advised to be continued indefinitely.
| Results|| |
Preoperative patient characteristics
Ten eyes of 10 patients underwent KPro implantation during the study period (1 patient underwent a second implantation after KPro extrusion) [Table 1]. There were seven males and three females. The mean age of patients was 45.4 years (range, 32–60 years). The mean follow-up period was 26.9 months (range, 12–54 months). Five patients (50%) were operated for multiple failed grafts, three patients (30%) had corneal scarring with severe corneal neovascularization secondary to chemical injury (alkali burn), and two patients (20%) had a history of Stevens–Johnson syndrome. The average number of grafts per patients was 1.2 (ranging from 0 to 2). Preoperative vision was hand movement close to face in six patients (60%) and counting finger close to face in four patients (40%).
|Table 1: Demographic data, indication of surgery, number of prior grafts, type of keratoprosthesis, visual acuity (in LogMAR) preoperative and at follow-up, complications, and their management|
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We used aphakic AKPro in seven patients (70%) and aphakic BKPro in three cases (30%). No intraoperative complication occurred in any case. Concomitant procedures included anterior vitrectomy in four patients, two had amniotic membrane transplant, and symblepharon release performed in one patient, along with the primary procedure.
Glaucoma and keratoprosthesis
The one patient with preoperative glaucoma eventually required surgical intervention to tackle glaucoma progression. After implantation of KPro, elevated intraocular pressure (as estimated by tactile tension) was present in four eyes (40%) which were then treated with anti-glaucoma medication (AGM). One patient (10%) underwent concomitant glaucoma drainage device (Ahmed glaucoma valve [AGV]) implantation.
Visual acuity outcomes
Immediate postoperative vision improved to >6/60 in three patients (30%). At 1-month follow-up, eight patients had a vision ≥6/60 (80%). At 1-year follow-up, eight patients had a VA ≥6/60 (80%) [Graph 1]. Of the five patients with diminution of vision, four suffered blurring of vision due to glaucoma and one developed graft melt. The graft melt patient developed KPro extrusion requiring re-KPro implantation. The anatomic retention rate of the initial KPro was 90% (9/10). The re-KPro patient underwent phthisical changes at 36 months of follow-up.
Postoperative complications and management
The most common nonsurgical complication was retroprosthetic membrane (RPM) formation, seven eyes (70%) all of which were treated with neodymium: yttrium–aluminum–garnet Nd: YAG laser membranotomy [Figure 1]. The mean follow-up at which they developed RPM was 16.4 ± 6.06 months. Other nonsurgical complications encountered included increased intraocular pressure (4 eyes, 40%), corneal melt (1 eye, 10%), progression of glaucoma (1 eye, 10%), and phthisis bulbi (1 eye, 10%). Other procedures performed after initial KPro implantation included KPro replacement (1 eye, 10% of patients), YAG laser capsulotomy (7 eyes, 70%), and corneal patch graft (1 eye, 10%).
|Figure 1: Slit-lamp photographs. (a) Keratoprosthesis at 1-month follow-up. (b) Epithelial defect noted on fluorescein staining after removal of bandage contact lens. (c) Retroprosthetic membrane formation, visually significant. (d) After neodymium: yttrium–aluminum–garnet laser membranotomy|
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The retention rate of the initial KPro at an average follow-up of 26.9 ± 14.85 months was 90%, with only one failure. The cause of failure was corneal melting. This patient underwent KPro replacement and subsequently developed phthisis bulbi.
| Discussion|| |
KPro is a viable option to treat the challenging high-risk end-stage corneal blind patients, who have a high failure and rejection rates for traditional penetrating keratoplasty. Good results with respect to the visual rehabilitation and anatomical retention have already been described in the literature., The other treatment modalities that could be used are bioengineered, collagen-based corneal scaffolds, but these are still in the experimental stage. Hence, KPro remains the only available option for these patients.
The most common indication for surgery in our study was multiple failed graft which is in line with the previous studies., KPro in our study was performed on patients with poor vision (preoperative vision ≤ counting finger close to face) and one of the patients had preexisting glaucoma (10%). There was significant improvement in mean best-corrected VA (BCVA) after the surgery (P < 0.001). Eight patients (80%) had a final VA better than 6/60 at the 1-year follow-up. The results of our study are also comparable to the studies by Aldave et al. (75% achieving BCVA 6/60 after 1 year), Zerbe et al. (57% achieving BCVA 6/60 at an average of 8.5 months), and Chew et al. (89% achieving BCVA 6/60 after 14 months).,, Variation in the percentage of patients achieving improved VA after surgery may be due to difference in initiating insult and large pool of surgeons.
The postoperative complications were compared to the previous studies and tabulated [Table 1]. In our study, the most common postoperative complication observed was the formation of RPM (7 eyes, 70%) and is comparable to previous studies.,, They were subsequently treated with YAG laser membranotomy with favorable outcome. Literature review showed that no clear cause for these membranes could be identified. In the absence of a clear cause and in view of excellent treatment response to the YAG laser membranotomy, early detection and treatment seem to be the most acceptable approach in these cases with RPM formation.
Glaucoma was the second most common postoperative complications observed and is most significant as it impacts vision and is resistant to treatment. In our study, one patient who had preexisting glaucoma and the three who developed glaucoma after the surgery, all four (40%) required the administration of AGM. The patient with preexisting glaucoma later required implantation of AGV. The other alternatives such as transscleral or endoscopic cyclophotocoagulation should be considered carefully in glaucoma management.
The other alternative to KPro implantation could be keratolimbal allograft with or without subsequent keratoplasty. Solomon et al. and Ilari and Daya have reported that keratolimbal autograft can restore the corneal epithelium and outcomes are comparable to those of KPro surgery., However, the downside of this procedure is requirement of chronic systemic immunosuppression for graft survival.
After initial gain in VA, a drop in VA was observed during the follow-up similar to that seen in the study by Sharma et al. and Chew et al., This drop could be attributed to glaucoma and its progression and it continues to pose a significant challenge in maintaining good VA in long term. Thus, the authors would like to emphasize on the need for glaucoma and retina team in tackling the postoperative complications and maintain VA in the long term.
The indications, techniques, and outcomes of KPro surgery have been reviewed in the literature previously, but this case series is first of its kind from the northeast part of our country. Since, the sample size used in this study was a small one, the future studies with a much larger cohort with a longer follow-up will be required to understand the long-term results.
| Conclusions|| |
Thus, to conclude, the initial results of this study appear promising and encouraging. This study also emphasizes the need for management of the post operative complications related to the prosthesis, which the surgeons and the patients must anticipate.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
We would like to thank Sri Kanchi Sankara Health and Educational Foundation, Guwahati, India.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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