Archives of International Surgery

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 8  |  Issue : 3  |  Page : 101--107

Early experience with penetrating keratoplasty in South-South Nigeria: Initial audit of indications and outcome


Ukeme I E Umana1, Ernest I Ezeh2, Dennis G Nkanga3, Utam A Utam4, Affiong A Ibanga5, Bassey A Etim3, Elizabeth D Nkanga6, Sylvia I Akpan7,  
1 Marion Eye Centre, Marion, Illinios, USA; Zerah Eye Hospital and Laser Centre, Calabar, Cross River State, Nigeria
2 Department of Ophthalmology, University of Calabar, PMB 1115; Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Nigeria
3 Zerah Eye Hospital and Laser Centre, Calabar, Cross River State; Department of Ophthalmology, University of Calabar, PMB 1115; Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Nigeria
4 Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Nigeria
5 Zerah Eye Hospital and Laser Centre, Calabar, Cross River State; Department of Ophthalmology, University of Calabar, PMB 1115, Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Nigeria
6 Zerah Eye Hospital and Laser Centre, Calabar, Cross River State; Department of Ophthalmology, University of Calabar Teaching Hospital, Calabar, Nigeria
7 Zerah Eye Hospital and Laser Centre, Calabar, Cross River State; Department of Ophthalmology, University of Uyo, Uyo, Akwa Ibom State, Nigeria

Correspondence Address:
Dr. Ernest I Ezeh
University of Calabar, Cross River State/University of Calabar Teaching Hospital, Calabar, Cross River State
Nigeria

Abstract

Background: Corneal diseases are major causes of severe visual impairment and blindness in developing countries, unfortunately. Keratoplasty, which is a major treatment modality, is either nonexistent or at its infancy in these climes. Indications for penetrating keratoplasty (PKP) and the short-term success and survival rates vary in different geographical locations. We sought to evaluate the indications and short-term success rates of penetrating keratoplasty (PKP) in a Nigerian Private Practice Setting in South South Nigeria. Patients and Methods: It was a retrospective audit of 12 patients that had undertaken PKP in the hospital by December 2017. Data obtained from medical records included demographic information like age and sex. Others included preoperative diagnosis, indications for surgery, and pre- and postoperative best corrected visual acuity (BCVA) of subjects. Other information included intraocular pressure pre- and postoperatively, levels of corneal clarity, presence of other ocular comorbidities, and documentation of preoperative graft failure risk assessments. All patients in the series had optical penetrating keratoplasty, performed by a single experienced surgeon for purpose of vision restoration. Results: The mean age of the patients was 50.1 years, with a standard deviation of ± 15.5 years. The indications for PKP were bullous keratopathy seven (58.3%) and five corneal scars (41.7%). The etiological distribution was six patients with pseudophakic bullous keratopathy, one patient was postuveitic bullous keratopathy, three patients were postinfectious corneal scar, and two patients were postmeasles adherent leucomatous corneal scar. Pre-PKP 10 patients (83.4%) were corneal blind on the affected eye and the corneal clarity grades were 2 patients (16.7%) in grade 0, 7 patients (58.3%) in grade 1, and 3 patients (25.0%) in grade 2. At 6 months post-PKP, three patients (25.0%) remain blind in the affected eye, two patients (16.7%) in pre-PKP blind category moved to SVI, one patient (8.3%) with SVI and five patients (41.7%) with blindness at pre-PKP had respectively moved to MVI, and one patient (8.3%) with MVI at pre-PKP had regained normal vision. At 6 months post-PKP, corneal clarity improved from grades 0–2 to grades 3 and 4, in 25% and 75% of the patients, respectively, compared to the pre-PKP grades 0, 1, and 2, in 16.7%, 58.3%, and 25.0% of patients, respectively. Conclusion: In this study, bullous keratopathy and corneal scar were the main indications for penetrating keratoplasty. The short-term (6 months) success and survival of corneal grafts were reasonably good.



How to cite this article:
Umana UI, Ezeh EI, Nkanga DG, Utam UA, Ibanga AA, Etim BA, Nkanga ED, Akpan SI. Early experience with penetrating keratoplasty in South-South Nigeria: Initial audit of indications and outcome.Arch Int Surg 2018;8:101-107


How to cite this URL:
Umana UI, Ezeh EI, Nkanga DG, Utam UA, Ibanga AA, Etim BA, Nkanga ED, Akpan SI. Early experience with penetrating keratoplasty in South-South Nigeria: Initial audit of indications and outcome. Arch Int Surg [serial online] 2018 [cited 2019 Dec 8 ];8:101-107
Available from: http://www.archintsurg.org/text.asp?2018/8/3/101/268128


Full Text



 Introduction



Corneal diseases are major causes of severe visual impairment and blindness in developing countries where blindness constitutes a major socioeconomic burden.[1] Corneal infections and inflammatory conditions are still very prevalent in these settings where, unfortunately, keratoplasty is either nonexistent or at its infancy. Bilateral corneal blindness has been reported to be the second most common cause of blindness in developing countries with estimates of 4.9 million persons or 12% of 39 million blind.[2]

Estimate of corneal blindness is highest in Africa (11–30%).[3] Global estimate for unilateral corneal blindness stands at a staggering 23 million.[4] Corneal infections and trauma constitute significant causes of scarring in the cornea with a resultant visual impairment and blindness.[5] In Nigeria, corneal scarring is the third commonest cause of blindness (13.29%).[6]

Corneal blindness is largely avoidable, affecting younger people when compared to cataract blindness.[7],[8],[9],[10] The strong association between corneal diseases and poverty in the developing world often also means that the majority of patients cannot afford to pay for sight restorative treatment including keratoplasty. Millions are therefore affected every year even by conservative estimates and their blindness often is underreported.[11]

Keratoplasty is one of few procedures to restore vision in corneal blindness. Its success rate is reported to be low in developing countries (46.5%) as compared to developed countries.[4] There are many reports on indications and outcome of penetrating keratoplasty (PKP) in developed countries, fewer reports from developing countries but none from the South South region of Nigeria. This is the gap that study is designed to fill. This study, a retrospective audit of our early experience with PKP in a Nigerian Private Practice Setting South South Nigeria, sought to evaluate the indications and short-term success rates of PKP by assessing visual and other standard outcome parameters at 6 months.

 Patients and Methods



Necessary permission and approvals were obtained from the management of Zerah Eye Centre, Uyo, Nigeria, to conduct a retrospective audit of all their patients that had undertaken PKP in the hospital by December 2017. Patients of PKP with follow-up less than six months were excluded from the study.

Data obtained from medical records included demographic information like age and sex. Others included preoperative (pre-OP) diagnosis, indications for surgery, and pre-OP and postoperative BCVA of subjects. Other information included intraocular pressure pre-OP and postoperatively, levels of corneal clarity, presence of other ocular comorbidities, and documentation of pre-OP graft failure risk assessments. All patients in the series had optical penetrating keratoplasty, performed by a single experienced surgeon for purpose of vision restoration.

Surgical details were noted including grades of the graft used and any additional procedures like cataract surgery, trabeculectomy, intraocular lens explantation, vitrectomy, goniosynechiolysis, etc. Donor corneal tissues, which were donated by SightLife, Inc., USA, were graded by grading chart by National Eye Bank as grades A, B+, B, B−, C, and D. Only donor tissues graded A and B+ were used for PKP among study subjects. Most of the patients could not afford to make any payment for the procedure and therefore had the PKP on charitable bases.

All PKPs were performed under peribulbar anesthesia. Standard technique of keratoplasty with donor grafts 0.5 mm larger than the recipient was followed in all cases. A combination of interrupted and running suturing with 10-0 nylon sutures was done for all patients. Routine postoperative medication consisted of topical prednisolone 1% combined with topical antibiotic six times daily along with artificial tears. Routine follow-up schedule was weekly for the first month, biweekly for the second month, and monthly for 3–6 month. Topical antibiotic was reduced over the subsequent postoperative month and 1% prednisolone tapered down after 6 months with once daily dose lifelong.

No patient had systemic immunosuppressive therapy. The suture removal was scheduled to be performed after 1 year except for one case where selective interrupted sutures were removed at 3 months as they were associated with infiltrates.

Data were analyzed using SPSS version 22. Descriptive statistics (frequencies, percentages, mean, and standard deviation) were employed.

Definition of terms

Corneal/Graft clarity level

Corneal/Graft clarity was graded as grade 4 if cornea/grafts were optically clear with excellent view of iris details, grades 2–3 (borderline) if there was moderate-to-significant corneal haze with or without good view of iris details, and grades 1–0 (failed) for opaque grafts with poor view of iris and anterior segment details.[12]

Recipient graft failure risk

Failure risk was categorized as “high risk” if (1) recipient's cornea has >2 quadrants of stromal vascularization or (2) has had previous immunological graft failure, as “very high risk” if both conditions mentioned above exist, as “moderate risk” if aphakic or pseudophakic bullous keratopathy, adherent leucomas, corneal scars following perforations, descemetoceles but <2 quadrants of stromal vascularization, and “low risk” if quiet eyes with inactive corneal scars, corneal degenerations, and dystrophies with no corneal vascularization.[12]

Corneal graft failure

Corneal graft failure refers to a regraft or, in the absence of regraft, a cloudy cornea in which there was a loss of central graft clarity sufficient to compromise vision for a minimum of three consecutive months.[12]

A World Health Organization [13] category of vision loss was used to define blindness and visual impairment. Presenting visual acuity (PVA) is defined by the visual acuity in the better eye using currently available refractive correction, if any. Where the participant has no refractive correction (distance glasses), the unaided distance VA defines the PVA.

≥6/18 in the better eye: No visual impairment (normal)<6/18–6/60 in the better eye: Moderate visual impairment (MVI)<6/60–3/60 in the better eye: Severe visual impairment (SVI)<3/60 in the better eye: Blindness (BL).

 Results



The mean age of the patients was 50.1 years, with a standard deviation of ±15.5 years. The oldest patient was 72 years and the youngest patient was 19 years. Out of the 12 patients, 7 were male and 5 female.

A. Indications

The indications for PKP were bullous keratopathy 7 (58.3%) and 5 corneal scars (41.7%) [Figure 1].{Figure 1}

The etiological distribution was as follows: six patients were pseudophakic bullous keratopathy, one patient was postuveitic bullous keratopathy, three patients were postinfectious corneal scar, and two patients were postmeasles adherent leucomatous corneal scar [Figure 2].{Figure 2}

B. Procedure

[Table 1] shows that out of the 12 patients, ten patients (83.3%) underwent only PKP and two patients (16.7%) underwent triple procedure (PKP + cataract extraction + posterior chamber intraocular lens implantation). All the patients had the procedure in one eye.{Table 1}

C. Pre-PKP ocular status of the patients

i. Visual status

Ten patients (83.4%) were blind in the affected eye, one patient (8.3%) had moderate visual impairment, and one patient (8.3%) had severe visual impairment, respectively [Table 2].{Table 2}

Pre-OP corneal clarity level

In five patients (71.4%), the cornea was opaque with a poor view of anterior chamber/iris details (grades 0–1). Two patients (28.6%) had opaque cornea with fair view of iris details (grade 2/3) [Table 3].{Table 3}

ii. Presence of ocular comorbidity

[Table 4] depicts the types of ocular comorbidity in these patients. Eight patients (66.7%) had associated visually significant ocular comorbidities, which included amblyopia in 3 (37.5%), anterior chamber intraocular lens + posterior capsular rent in 4 (50.0%), and repeat PKP in 1 (12.5%).{Table 4}

iii. Graft failure risk

[Table 5] presents the distribution of recipient graft failure risk in the participants. Recipients' corneal-related risk for graft failure was high in seven patients (58.3%), very high in two patient (16.7%), and low on three patient (25.0%).{Table 5}

D. Ocular status at 6 months post-PKP

i. Visual status

At 6 months post-PKP, one patient had normal vision, six patients (50.0%) were in the moderate visual impairment category, while two patients (16.7%) and three patients (25.0%) were in severe visual impairment and blindness category, respectively [Table 6].{Table 6}

Comparison of visual category pre-PKP versus post-PKP among PKP patients

[Figure 3] shows the frequency distribution of the visual category pre- and post-PKP. The post-PKP visual acuity at the end of 6 months was between ≥6/18 in 1 patient (8.3%) and none (0%) at pre-PKP, <6/18–6/60 in 6 patients (50.0%) versus 1 patient (8.3%) at pre-PKP, <6/60–3/60 in 2 patients (16.7%) versus 1 patient (8.3%) at pre-PKP, and <3/60 in 3 patients (25.0%) versus 10 patients (83.4%) at pre-PKP. Out of 10 patients with blindness at pre-PKP, 3 patients remained blind, 2 patients improved to SVI, and 5 patients improved to MVI [Table 7].{Figure 3}{Table 7}

ii. Post-PKP Graft Clarity

At 6 months post-PKP, nine patients (75.0%) had grade 4 graft clarity, while three patients (25.0%) had grade 3 graft clarity [Table 8].{Table 8}

Comparison of Corneal graft clarity pre- versus post-PKP among the PKP patients

[Figure 4] shows the frequency distribution of the corneal graft clarity at pre- and post-PKP. The post-PKP corneal graft clarity at the end of 6 months were grades 3 and 4, at 25% and 75%, respectively, compared to the pre-PKP grades 0, 1, and 2, at 16.7%, 58.3%, and 25.0%, respectively. [Figure 5] shows the pre PKP state and post PKP state of a case of dense central corneal leucoma.{Figure 4}{Figure 5}

 Discussion



Corneal blindness is a major health problem,[7] particularly in developing countries where corneal transplantation facilities are scarcely available.

In this study, bullous keratopathy (58.3%) was the leading indication for PKP followed by infectious-related corneal scar (41.7%). Hassan et al.[14] had similarly reported in their study among Nigerians undergoing PKP that the leading indication for PKP was bullous keratopathy (31.4%) followed by infectious keratitis (18.6%) and repeat PKP (14.3%). Changing trends in the indications for PKP as well as variation in indications in different regions have been widely reported.[8],[11],[15] In developed economies, the common indications for PKP are pseudophakic bullous keratopathy, keratoconus, failed grafts, and corneal dystrophy.[8],[16],[17],[18],[19],[20] In contrast, in less developed economies such as India,[9] Nepal,[10] and Taiwan,[11] as well as in rural communities, Northern China [21] and Northern India,[22] corneal scar and active keratitis are the most common indications for PKP. Keratoconus constitutes the most common indication for corneal transplantation in some other countries.[15],[23],[24],[25],[26] Reports from various graft registries of the developed countries show the indications for surgery being mainly keratoconus, and other corneal dystrophies, followed by aphakic and pseudophakic bullous keratopathies.[8],[15],[16],[17],[18],[19],[20],[22],[23],[24],[25],[26] However, the scenario in the developing world is quite different. First, the patient profile and indications for surgery differ. Corneal scars following infectious keratitis, adherent leucomas, and corneal perforations are major contributors to the indications for PKP in developing countries. They are different from the western studies essentially due to differences in patient profile, different indications for surgery, differences in methods of storage of corneas, and socioeconomic factors affecting health-care provision.[27]

The Nigeria National Blindness and Visual Impairment survey [6] reported the causes of corneal blindness as follows: infectious-related corneal scarring 34.8%, noninfectious-related corneal scarring 24.6%, undetermined causes 17.4%, and surgical procedures 4.3%. However, bullous keratopathy appears to be the leading indication for PKP, as noted in our study as well as reported by Hassan et al.[14] The majority of cases of bullous keratopathy, in our center, included pseudophakic patients (50.0%). This may notably be attributed to the shift in the technique of cataract surgery from extracapsular extraction to small incision cataract surgery with more damage to corneal endothelial cells.[21],[28] This suggests the need for more training and retraining on small incision cataract surgeries in our environment.

The short-term success and survival of corneal grafts in this group are reasonably good. Out of 10 unilateral blind patients, 2 patients (16.7%) moved to SVI while 5 patients (41.7%) moved to MVI. The patient with pre-OP MVI regained normal vision. Similarly, corneal clarity improved from grades 0–2 to grades 3–4. Despite high (75.0%) recipients' cornea-related risk for graft failure and certain post-PKP challenges such as postoperative graft edema, snap suture, epithelial/endothelial reactions, and Descemet's folds, the reasonably good short-term (6 months post-PKP) visual success (75.0%) and survival of corneal grafts (100%) are quite encouraging. This compares to reported short-term survival rates (1 year) of 70% and 79.6% by Shanbhag et al.[27] and Dandona et al.,[29] respectively, in India, but lower than 90% short-term survival rates from Australian corneal graft registry.[30] By taking care of the pre-OP and postoperative factors responsible for graft rejection, our study has shown that a reasonably good PKP outcome is possible.

 Conclusion



Evidence from this study has shown a reasonably good short-term (6 months) success and survival of corneal grafts in this part of the developing world. By taking care of the pre-OP and postoperative factors responsible for graft rejection, our study suggests an acceptable outcome of PKP, irrespective of the indication for the procedure. However, this may not be conclusive as larger patient series and longer follow-up of these patients are required for over 5–10 years.

Bullous keratopathy and infectious-related corneal scar were the main indications for PKP in this study. Since the developing world carries most of the load of corneal blindness and the major causes of corneal blindness are corneal scar and active keratitis, the development of affordable corneal transplantation services needs a comprehensive approach encompassing medical standards in eye banking, training of cornea specialists and eye banking personnel as well as exposure of ophthalmologists to care of corneal transplants for better follow-up care.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/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.

Acknowledgments

The authors thank SightLife, Inc., USA, for graciously donating donor corneal tissues and the management of Zerah International Eye Hospital, Uyo, Akwa Ibom State, Nigeria, for providing the technical and infrastructural support for the corneal transplant procedures.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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