|Year : 2019 | Volume
| Issue : 2 | Page : 34-39
Indications and visual outcome following penetrating keratoplasty at tertiary health-care institution
Prabhakar Srinivasapuram Krishnacharya, Raghavender A Arra
Department of Ophthalmology, JSS Medical College Hospital, JSS University, Mysore, Karnataka, India
|Date of Submission||05-Nov-2017|
|Date of Acceptance||14-Aug-2020|
|Date of Web Publication||27-Nov-2020|
Prof. Prabhakar Srinivasapuram Krishnacharya
57, 4th Main, 8th Cross, Vinayaka Nagara, Mysore - 570 012, Karnataka
Context: Success rate after keratoplasty is dependent on recipients' anterior segment status and donors' corneal parameters.
Aims: The aim of this study is to investigate indications and visual outcome.
Settings and Design: Prospective interventional.
Patients and Methods: The present study recruited 30 eyes and donor cornea graded by slit -lamp microscope. Patients followed up at 3, 6, 12, and 18 months for visual acuity (VA) and graft survival. Quality of life (QOL) was evaluated by the Visual Analog Scale. Primary outcome measures were VA and graft clarity and secondary outcome was QOL. Statistical significance considered at or <0.05 for P value.
Statistical Analysis: SPSS software version 20.
Results: Mean age of 55.5 (±17.06 standard deviation) years ranging from 17 to 86 was enrolled. Optical keratoplasty executed in 23 (76.66%) and therapeutic in 7 (23.33%) eyes. Pseudophakic bullous keratopathy (PBK) was diagnosed in 33.33%, recalcitrant corneal ulcer in 23.33%, corneal opacities in 20%, and previous graft failures in 20%. Grade A corneas transplanted in 93.2% of eyes. Phi and Cramer's V test showed 0.404 each between variables for vascularization and graft survival. Wilcoxon test for QOL showed P and Z values of 0.001 and − 3.247.
Conclusions: PBK was the most common indication with satisfactory vision as well for recalcitrant corneal ulcers with statistical significant QOL. Vascularisation was the high risk factor for graft failure. PBK and keratoconus showed 100% survival rates at 12 and 18 months. At 18 months, graft survival rate was 60% and 93%, respectively, in patients with and without vascularization.
Keywords: Graft survival rate, penetrating keratoplasty, pseudophakic bullous keratopathy, quality of life
|How to cite this article:|
Krishnacharya PS, Arra RA. Indications and visual outcome following penetrating keratoplasty at tertiary health-care institution. Albasar Int J Ophthalmol 2019;6:34-9
|How to cite this URL:|
Krishnacharya PS, Arra RA. Indications and visual outcome following penetrating keratoplasty at tertiary health-care institution. Albasar Int J Ophthalmol [serial online] 2019 [cited 2021 Sep 19];6:34-9. Available from: https://www.bijojournal.org/text.asp?2019/6/2/34/301683
| Introduction|| |
Indications for corneal transplantation have been changing over time and differ based on socioeconomical status of a country. Familiarity with the epidemiology of corneal pathologies and indications for keratoplasty facilitate in instituting appropriate management, understanding the changing trends in keratoplasty and to compare the outcome specific for each indication.
According to WHO, “Blindness” is defined as visual acuity (VA) <3/60 or a corresponding visual field loss <10° in the better eye with the best possible correction. In India, 6.8 million people constitute the spectrum of corneal blindness with <6/60 vision in at least one eye, out of which, about 1 million are bilaterally corneal blind. Keratoplasty restores the vision in corneal blind patients, and its success rate is low in developing countries (46.5%) as compared to developed countries.
According to the North and South Indian studies, corneal scarring and infectious keratitis are the most common indications for penetrating keratoplasty (PKP)., In developed countries, bullous keratopathy remains to be the most common indication for corneal transplantation. Infectious corneal diseases and corneal scars are more prevalent in developing countries.,,,
This study aims to discover the recent trends of indications for PKP, especially in South Indian population and to find out the outcome in terms of visual improvement, graft clarity, and quality of life (QOL)specific to each indication.
| Patients and Methods|| |
This prospective and interventional study was carried out between June 2014 and June 2016 after obtaining Institutional Ethical Committee clearance and informed written consent from the study patients that provided the source of data. The study population included 30 eyes of thirty patients attending ophthalmology outpatient department fulfilling the inclusion and exclusion criteria.
All corneal blinding disorders were included in the inclusion criteria and disorders with poor visual outcome expectation as in posterior segment disorders were excluded. Statistical analyses were performed by the SPSS software version 20 IBM, Armonk, New York 10504-1722, United States that included descriptive statistics, Chi-square test, Kaplan-Meier survival analysis, Wilcox on signed-rank test, Phi and Cramer's V test.
Following enucleation, donor eyes were preserved in a moist chamber until slit-lamp examination was performed for corneal grading purpose. Moreover, after ruling out contraindications for keratoplasty by confirming the negative results of donor blood for HIV and Hepatitis B, corneal transplantation was performed within 24 h after enucleation.
Corneal grading method
- A– grade
- Clear cornea (Iris structure and architecture clearly visible)
- Less than 5 Descemets folds and/or striae
- No corneal opacities or vascularizations
- No features suggestive of exposure keratitis with intact epithelium
- Age <50 and phakic.
- Mild-to-moderate Corneal haze (Iris structure and pattern hazily visible)
- 5–10 descemets folds and/or striae
- No corneal opacities in the central optical zone or paracentral zone
- Mild-to-moderate exposure keratitis
- Vascularizations in 1 or 2 quadrants.
- Marked cloudy cornea (Iris details barely made out)
- More than 10 Descemets folds and/or striae
- Corneal opacities in the central optical zone or paracentral zone
- Severe exposure keratitis
- Vascularizations in more than two quadrants.
Preoperative evaluation of recipient included detailed history and VA recording; slit-lamp biomicroscopic examination, direct and indirect ophthalmoscopy in feasible cases, B-scan ultrasonography in opaque ocular media, Keratometry and A-scan considering the fellow eyes measurements for patients planned for triple surgery, intraocular pressure (IOP) recorded by I Care tonometer, and QOL by scoring method.
Quality of life scoring
In this scoring system, one point was awarded for each performance in QOL which consists of maximum score of 5. Points based on patient's ability to perform the activities mentioned below and none if the patient could not perform them. Scoring was done before and after the surgery.
- Walking without support
- Eating without help
- Reading and writing
- Having bath and going to washroom without help
- Absence of impact on occupation.
Surgical procedure was performed either under retrobulbar or peribulbar anesthesia. Whole globe was stabilized with sterile ribbon gauge under microscope and trephination of 7–7.5 mm of donor corneal button was prepared. Moreover, then donor graft was anchored to recipient bed with continuous or intermittent/combined sutures with 10.0 Ethilon suture and bandage soft contact lens was placed at the end of surgery. Postoperative management included topical moxifloxacin and dexamethazone one drop hourly during the first 2 postoperative weeks and tapered gradually over 2–3 months. Oral acetazolamide and prednisolone were administered depending on the severity of postoperative inflammation.
All the patients were followed up at the 1st week, 1st, 3rd, 6th, 12th, and 18th months. Suture removal was performed within 1 year after the surgery or earlier if infective signs were discovered. Detailed examination with slit-lamp microscope, uncorrected and best corrected VA recording, and IOP measurements by I Care tonometer was performed at each follow-up.
| Results|| |
In the present study, 30 eyes of 30 patients ranging from 17 to 86 years underwent PKP. Males and females were 23 (76.66%) and 7 (23.33%), respectively. Most of the patients (53.33%) were in the age group of 41–65 years. The mean age in males was 57.8 years and 47.8 years in females. The right eye was operated in 23 (76.66%) patients and left eye in 7 (23.33%) patients. Optical keratoplasty was done in 23 patients (76.66%) and therapeutic keratoplasty in 7 (23.33%).
Indications for PKP in decreasing order of frequency are shown in [Table 1]. The association between graft clarity with pre-PKP recipient corneal vascularization was determined by phi and Cramer's V test, as shown in [Table 2]. Comparison of PKP indications of the present study and published literature is depicted in [Table 3]. Mean pre-PKP and post-PKP QOL scores were 3.06 and 3.76, respectively. Improvement in QOL score following surgery was analyzed by Wilcox on signed-rank test that showed P = 0.001 and Z = −3.247.
|Table 2: Phi and Cramer's V test between graft clarity and corneal vascularization|
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|Table 3: Analysis of penetrating keratoplasty indications of the present study with the published literature|
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Eleven (36.66%) donor corneas were of A-grade quality and 17 corneas (56.66%) were of B-grade which was transplanted for optical purposes. Mean age of the donor for A-grade cornea was 57.36 years, for B-grade was 69.1 years, and for C-grade, it was 76 years. PKP alone was performed in 25 (83.33%) eyes, PKP with lens extraction in 2 (6.66%) eyes, PKP with scleral fixation in 1 (3.33%) eye, PKP with anterior vitrectomy in 1 (3.33%) eye, and triple procedure was done in 1 (3.33%), as shown in [Figure 1].
|Figure 1: Pie diagram showing various surgical procedures performed in this present study|
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Visual outcome specific to each indication was determined by improvement in VA following surgery and analyzed using the paired samples t-test. Twenty-eight patients had VA of 3/60 or less before surgery. Moreover, following surgery 14 (46.6%) patients had VA of 4/60 or better. Kaplan–Meier analysis was performed to study the corneal graft survival rate. Survival rate for pseudophakic bullous keratopathy (PBK) was 82% and 65%, 50% and 50% for corneal ulcer, and 100% and 82% for corneal opacity, respectively, at 6th and 18th months, as shown in [Figure 2].
|Figure 2: Showing Kaplan–Meier survival analysis for various indications|
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Effect of vascularization on graft survival was also determined by the Kaplan–Meier analysis. The 6th and 18th month graft survival rates in patients with vascularization of host cornea was 65% and 60%, respectively, and in patients without vascularization of host cornea was 100% and 93%, as shown in [Figure 3]. Of the 24 (80%) patients with clear graft, 16 (53.3%) patients had no corneal vascularization and 8 (26.66%) patients had corneal vascularization. Of the 6 (20%) patients with hazy graft, 1 (3.33%) patient had no corneal vascularization and 5 (16.66%) patients had corneal vascularization. Pre-PKP VA and final VA gain at the last follow-up at 12th months are shown in [Figure 4].
|Figure 3: Showing Kaplan–Meier analysis of corneal graft survival with respect to corneal vascularisation|
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|Figure 4: Showing prepenetrating keratoplasty visual acuity and final visual acuity gain at the last follow-up|
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| Discussion|| |
As the number of keratoplasties performed in India are increasing day by day, the indications for which they are being performed has been varying. In the present study, the most common indication for PKP was PBK followed by infectious keratitis, corneal opacities, previous graft failures, and keratoconus in the decreasing order of frequency. Although India is a developing country, common indication for surgery was similar to the developed world due to the increase in the number of cataract surgeries being performed both in the urban and rural areas to achieve the targeted backlog of cataract cases.
Pseudophakic bullous keratopathy indications
Of the 7 patients who underwent PKP for therapeutic purposes, three patients had bacterial corneal ulcer and 1 patient had mixed bacterial and fungal infection. Culture report from three patients was negative for fungal and bacterial microorganisms possibly due to recipient inflammatory response or application of topical broad-spectrum antibiotics before corneal scrapping. One patient developed endophthalmitis in early postoperative period and due to inadequate control by medications enucleation was resorted to.
According to Hood et al.'s study, 487 (4.5%) patients had postoperative corneal infections. In the present study, 13.3% had postoperative post-PK-related infections. While suture-related problems and persistent epithelial defects are predisposing factors, infectious keratitis was the leading cause for corneal graft failure., The risk factors found in recipients were exposure to vegetative injury, vigorous eye rubbing after exposure to foreign body or probably to bandage soft-contact lenses.
Visual acuity gain
Pre-PKP VA and final VA gains at the last 18 months follow-up is depicted in [Figure 4]. To compare the outcome specific to each indication, preoperative VA was compared to the postoperative VA by the paired samples t-test. PKP was performed for PBK (P < 0.0001) and corneal ulcer (P = 0.01) showed statistically significant improvement in the VA, whereas corneal opacities (P = 0.32) and previous graft failures (0.15%) showed improvement in VA; however, was not statistically significant possible because of the high rate of incidence of graft failure in patient operated for previously failed grafts with pre-existing corneal vascularisation and occurrence of post-PK infections in 3 of the six patients who underwent PK for corneal opacity.
Quality of life scoring method
Comparison of pre and postoperative QOL score with Wilcox on signed-rank test showed a statistically significant improvement in QOL following surgery with a P = 0.001.
Graft survival rates
Graft survival following repeat PKP for previous graft failures as an indication in the present study showed poor visual prognosis. Fifty percent of participants operated for graft failure as an indication had graft failure again as a complication. One of the factors responsible for recurrent graft failure is vascularization of the host cornea before surgery, the correlation of which had been statistically proved. In patients operated for graft failure, the event occurred within 6 months of surgery in all the three patients. Previous study showed traumatic corneal scaring was the leading indication for PKP in 113 (26.2%) eyes in contrast to PBK as the leading indication in the present study and similar 90% results reported for graft survival in keratoconus at 30 months follow-up.
Another study reported corneal opacities as the leading indication in 141 (44%) eyes, followed by keratoconus in 45 (14%), pseudophakic or aphakic bullous keratopathy in 28 (9%), previous graft failure in 18 (6%), and graft survival rate of 80% overall at 2 years. Uncorrected VA improved from baseline 2.09 (+/-0.67) to 1.53 (+/-1.03) Log Mar at 2 years. Raj et al. study revealed corneal scarring in 48 (33.10%) patients with therapeutic keratoplasty done in 30 (20.68%) cases and reported Infective keratitis either active or healed was the major indication for keratoplasty.
Corneal scarring as a common indication found in 60.7%, regrafting in 12.7%, PBK in 2.94%, and keratoconus in 4.9% cases. Healed infectious keratitis (72.88%) was the most common cause for corneal scarring and as the most common indication for keratoplasty in Southern India. Other studies reported corneal scar in 55.9%, which included 44 (19.2%) cases of corneal scar after viral keratitis and 30 (13.1%) cases of corneal scar after chemical/thermal burns, bullous keratopathy in 12.2% cases, regraft in 10.5%, keratoconus in 5.7% cases. The most common indications for PKP were corneal scar and bullous keratopathy similar to the present study analysis. Chen WL reported corneal scars in 27.9%, regraft in 21.0%, acute necrotizing and ulcerative keratitis in 17.9%, pseudophakic or aphakic bullous keratopathy in 17.6%, and keratoconus 2.5%. Interestingly, acute necrotizing and ulcerative keratitis was found to be the most frequent indication for regraft.
The present study revealed highest survival rates of 100% for PBK and keratoconus each at 6th, 12th, and 18th month's interval. The 6th month and 18th month survival rates for other indications were 82% and 65% for corneal ulcer; 50% and 50% for graft survival; 100% and 82% for corneal opacity, respectively. Dandona et al. found lower graft survival rate for patients with previous failed grafts compared to other indications similar to the present study findings.
The 6th and 18th month graft survival rates in patients with vascularization of host cornea were 65% and 60%, respectively, and graft survival rates in patients without vascularization of cornea was 100% and 93%, respectively, indicating better graft survival rates for patients without corneal vascularization. Phi and Cramer's V tests were performed to find out the strength of association between two variables. With a Phi value of 0.404, the strength of association between vascularization and graft failure was very strong, indicating presence of corneal vascularization which was associated with higher risk of graft failure. Other causes for poor visual outcome were graft failure, glaucoma, retinal detachment and endophthalmitis each in one eye, and post-PKP graft infection in three eyes.
| Conclusion|| |
From the present study, we conclude that PBK was the most common indication for corneal transplantation. Visual outcome and prognosis were statistically significant in patients with PBK and corneal ulcer. QOL scoring significantly improved following surgery. Vascularization of the host cornea was a high risk factor for graft failure with shorter graft survival rates. PBK and keratoconus revealed highest survival rates following PKP.
We profusely thank head of institution and ophthalmology, OT staff and patients, and their attendees for extending full support and cooperation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]