|Year : 2014 | Volume
| Issue : 1 | Page : 14-18
Incidence of increased intraocular pressure and factors associated with it after optical penetrating keratoplasty at secondary care centre, India
Kamal R Dodia1, Nirzari M Shah1, Rajesh K Chudasama2
1 Department of Ophthalmology, P. D. U. Medical College, Rajkot, Gujarat, India
2 Department of Community Medicine, P. D. U. Medical College, Rajkot, Gujarat, India
|Date of Web Publication||16-Aug-2014|
Rajesh K Chudasama
"Vandana Embroidery", Matoshree Complex, Sardar Nagar, Main Road, Rajkot - 360 001, Gujarat,
Background: An increase in intraocular pressure (IOP/glaucoma) any time after penetrating keratoplasty (PK) leads to a significant endothelial cell loss with dire consequences. The present study was conducted to know the incidence of increased IOP and factors associated with it following optical PK. Materials and Methods: A prospective study was conducted at Ophthalmology Department of PDU Medical College and Civil Hospital Rajkot, a secondary level center for 2 years from May 2010 to April 2012. A total of 50 patients admitted for optical PK during the study period were enrolled. Detailed history was elicited regarding ocular problem and any treatment taken for the same. Results: Nearly 30% of the patients reported an increase in IOP in the present study. Majority (58.0%) patients were above the age of 55 years. Based on preoperative diagnosis, increase in IOP was reported among patients with aphakic bullous keratopathy (100.0%), adherent leucoma (50.0%), graft failure (44.4%) and pseudophakic bullous keratopathy (25.0%). After 1 month of optical PK, 18.0% patients reported an increase in IOP, 28.0% after 2 months and 26.0% after 3 months. Out of 15 patients who reported an increase in IOP, 14 (93.3%) were given medical treatment and 1 (6.7%) patient required surgical treatment. Conclusion: Age above 55 years, preoperative diagnosis of adherent leucoma, aphakic eyes were major risk factors for the post-operative increase in IOP in the present study. Peak rise in IOP was reported following 2 months post keratoplasty. Post PK glaucoma in the majority of patients responded to medical treatment.
Keywords: Glaucoma, incidence, intraocular pressure, keratoplasty, risk factors
|How to cite this article:|
Dodia KR, Shah NM, Chudasama RK. Incidence of increased intraocular pressure and factors associated with it after optical penetrating keratoplasty at secondary care centre, India. Sudanese J Ophthalmol 2014;6:14-8
|How to cite this URL:|
Dodia KR, Shah NM, Chudasama RK. Incidence of increased intraocular pressure and factors associated with it after optical penetrating keratoplasty at secondary care centre, India. Sudanese J Ophthalmol [serial online] 2014 [cited 2019 Sep 20];6:14-8. Available from: http://www.sjopthal.net/text.asp?2014/6/1/14/138845
| Introduction|| |
Penetrating keratoplasty (PK) can be performed as an elective procedure to improve visual acuity or as an emergency procedure (emergency keratoplasty) to treat a perforated or non-healing corneal ulcer to remove the perforation site and save the eye (tectonic keratoplasty).  The successful outcomes enjoyed by patients who undergo modern PK and lamellar keratoplasty are the result of advances in operating microscope design, suture technology, surgical techniques, disposable trephine, corneal topography and the availability of carefully preserved corneal tissue, along with a better understanding of corneal and ocular surface physiology. This studies reported PK is safe, effective and a reasonable treatment for corneal blindness in many countries. ,
An increase in intraocular pressure (IOP) (glaucoma) any time after PK leads to a significant endothelial cell loss with dire consequences as the endothelial reserve is already low. This also results in damage to the optic nerve. The association between PK and glaucoma was first described by Irvine and Kaufman.  They also showed a rise in IOP was bi-peaked, the first in the immediate post-operative period (days to weeks) with IOP returning to normal in most cases and second in the last post-operative period (weeks to months).
Post PK rise in IOP is one of the most common cause for irreversible visual loss  and second leading cause for graft failure after rejection.  Timely diagnosis of post PK glaucoma with initiation of appropriate treatment is mandatory to preserve optimal graft clarity and optic nerve head function.  Post PK increase in IOP (glaucoma) is defined as an elevated IOP of greater than 21 mm of Hg, with or without associated visual filed loss or optic never head changes.  Diagnostic difficulty arises due to errors in tonometry recordings of a thick or astigmatic corneal graft. , The incidence of post PK increase in IOP has been reported to a range between 9% and 35% respectively. ,,, The present study was conducted to know about the incidence of increased IOP and factors associated with it after optical PK at secondary care center, India.
| Materials and methods|| |
A prospective study was conducted at Ophthalmology Department of PDU Medical College and Civil Hospital Rajkot, a secondary level center. The study was conducted for 2 years from May 2010 to April 2012 after taking ethical clearance from Institutional Ethical Committee. The study has been carried out to know about the incidence of increase in IOP following optical PK and factors associated with it. In total, 50 patients were admitted for optical PK during the study period were enrolled for the study.
The study included all patients of PK with following inclusion criteria; a candidate for optical PK, not a known case of glaucoma pre-operatively, with a non-infective condition and had undergone a non-complicated surgery. Each of the case was studied and assessed pre-operatively with a slit lamp biomicroscopy and fundus examination, if required. Detailed history was elicited regarding ocular problem and any treatment taken for same. IOP was measured by Schiotz Tonometer. Any systematic disease, if present was controlled pre-operatively. Lacrimal passage patency was checked by sac syringing. Whole globe enucleation was done with full aseptic precautions. In all the cases, donor eyes were used within 24 h of enucleation.
Pre-operative preparations included full anterior segment examination; full posterior segment examination with ultrasound B scans if required. Graft size was decided by slit lamp biomicroscopy. Eyeball was kept in gentamicin solution for about half an hour before surgery. Intravenous dose of antibiotic and steroid was given to each patient. Written consent was taken with an explanation of complications and prognosis. Intramuscular atropine and test dose of lignocaine was given half an hour before surgery. Topical iodine eye drop was instilled in the operative eye. Patient was taken in operation theatre and peribulbar block was given followed by application of super pinky's ball for 10 min.
During the operative procedure, the graft was taken from the donor eye using disposable trephine of appropriate size decided preoperatively and 0.5 mm larger than recipient's size. Graft was then secured over Teflon block with endothelial side up and viscoelastic substance was put over it. After proper anesthesia recipient bed was prepared using 0.5 mm less size trephine than the donor. Graft was applied after putting viscoelastic substance over iris surface and four primary sutures were taken in 12, 3, 6, and 9 o'clock position and the rest of the sutures were taken in interrupted fashion with 10-0 nylon. Per operative injection of Mannitol was given if required. Thorough povidone iodine wash was done at the end of surgery and the eye was given pressure pad bandage after giving subconjunctival injection of antibiotic and steroid.
During post-operative management, eye was opened after 24 h of surgery. Following standard regimen was given to all patients - topical gatifloxacin and dexamethasone eye drops 2 hourly, topical prednisolone eye drops 4 times a day and topical timolol eye drops twice a day. Subconjunctival injections of dexamethasone and amikacin were given. Systemic antibiotics and analgesics were given for 5 days.
During the follow-up examination, IOP was measured by Schiotz Tonometer, a non-invasive method routinely used for measuring IOP on the out-patient basis. After measuring the IOP, the Schiotz Tonometer was disinfected with Cidex solution and antibiotic drops were put in the patient`s conjunctival sac. The IOP was measured 4 times during the follow-up period - initially 1 week after the surgery and at the end of 1 st , 2 nd and 3 rd month of the surgery. The data was entered and analyzed by using statistical software Epi Info version 3.5.1 (Centre for Disease Prevention and Control, Atlanta, USA)  and Chi-square test was used for any association.
| Results|| |
A total of 50 eyes of 50 patients were enrolled and studied during 2 years of the study period. The analysis of demographic characteristics showed that majority (58.0%) patients were above the age of 55 years [Table 1], with a mean of 52.48 ± 19.47 years and range from 9 to 80 years. Nearly 54.0% male and 46.0% female were reported. Right eye was operated in 58.0% study participants. Preoperative diagnosis included mainly aphakic or pseudophakic bullous keratopathy (40.0%), followed by corneal opacity (24.0%), graft failure (18.0%), and adherent leucoma (12.0%). Status of the lens was pseudophakic in 82.0% patients. Majority patients (58.0%) had a vision between 6/60 and 6/18. About 30% patients reported an increase in IOP in the present study.
Various factors affecting IOP following post PK are shown in [Table 2]. Though the majority of patients were above 55 years of age, increase in IOP was reported mainly (66.7%) in 36-45 years age group, followed by 42.9% in 16-25 years age group and 27.6% in above 55 years age group. No significant association was found for any age group with an increase in IOP. No association was reported for gender. Increase in IOP was reported mainly among aphakic (50.0%) and pseudophakic (29.3%) patients, but no statistical association was found for the same. Based on the preoperative diagnosis, increase in IOP was reported among patients with aphakic bullous keratopathy (100.0%), adherent leucoma (50.0%), graft failure (44.4%), and pseudophakic bullous keratopathy (25.0%). One patient who received donor graft size of 10 mm and 30.4% patients with donor graft size of 8.5 mm reported an increase in IOP.
During the follow-up period, no cases were reported for an increase in IOP at the end of 1 week [Table 3]. After 1 month 18.0% patients reported an increase in IOP, 28.0% after 2 months and after 26.0% 3 months. Synechiae (46.7%) was the mainly reported complication, followed by iritis (40.0%) and vitreous block (13.3%) in the present study. Out of 15 patients who reported an increase in IOP, 14 (93.3%) were given medical treatment and in 1 (6.7%) patient required surgical treatment.
|Table 1: Baseline characteristics of patients operated for optical penetrating keratoplasty|
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| Discussion|| |
PK is considered to be a successful surgical procedure, which is in the large part, straightforward. However, postoperative rehabilitation after surgery is prolonged due to a slow healing process. The outcome of PKP depends upon indications, operative techniques and post-operative care. ,,, A great many of the factors that affect visual outcome are uncertain. This remains crucial with this procedure, to try to understand more about what may be achieved in the long term.  In this way, we cannot only improve patient selection for corneal transplantation, but also better counsel patients, giving them more realistic expectations regarding post-operative results.
The incidence of increase in IOP (glaucoma) was reported 30% in the present study (15/50 eyes). In some patients the condition became chronic resulting into a serious clinical problem for diagnosis and management. The reported incidence of glaucoma after keratoplasty varies from 9% to 42% in different countries. ,,,,,, The patient's age range from 9 to 80 years (with a mean of 52.48 ± 19.47 years), which was similar to other study.  Majority of patient's (58.0%) were above 55 years of age. Receiver age 60 years or more was considered as a major risk factor influencing high IOP after keratoplasty.  More male patients (54.0%) were reported in the present study, compare with the previous study. 
The risk factors for the increase in IOP in the present study included aphakic bullous keratopathy (40.0%), followed by corneal opacity (24.0%), graft failure (18.0%) and adherent leucoma (12.0%). Studies have reported aphakia, pseudophakia, glaucoma, regrafting and corneal perforation as an important risk factors. ,,,, Increase in IOP was reported mainly among aphakic (50.0%) and pseudophakic (29.3%) patients like previous study,  but no statistical association was found for same. The majority of aphakic and pseudophakic cases were having bullous keratopathy, so it was not possible to consider them as independent risk factors. Inflammatory processes associated with the surgery, synechiae formation and the effects of aphakia and pseudophakia on the angle structures were the most probable explanations for the increased PK incidence in the study. ,,,
In the present study, the donor graft size taken was 0.5 mm larger than the host in routine practice. A donor button of the same size as the host bed causes angle distortion and tissue compression that leads to elevated IOP after keratoplasty.  A study reported lower incidence of glaucoma (10%) suggesting that the decreased incidence of glaucoma following PK was may be due to oversized grafts used by them,  but in contrast present study reported high (30%) incidence of glaucoma. Further studies are required to decide the role of oversize graft on glaucoma after PK.
Synechiae (46.7%) was the mainly reported complication, followed by iritis (40.0%) and vitreous block (13.3%) in the present study. Studies have reported synechiae as the common complication after PK. , During the follow-up period, no cases were reported for an increase in IOP at the end of 1 week. After 1 month 18.0% patients reported an increase in IOP, 28.0% after 2 months and 26.0% after 3 months, indicating peak rise in IOP following 2 months of post PK. Study reported elevation in IOP after 3 months in New Zealand, higher than the present study. 
Various studies have reported 27-73.5% patients with increased IOP post PK responded to medical therapy while remaining required surgical treatment. ,,,, In contrast to these findings, present study reported that majority 93.3% (14/15 eyes) patients responded to medical treatment only without requiring any surgical intervention to control the IOP. Use of topical medications to control IOP is still the first line treatment of post PK glaucoma.  Beta adrenergic blocker - timolol was mainly used with carbonic anhydrase inhibitor - acetazolamide if required. Surgical treatment was required by only one patient. Anti-glaucoma surgery was conducted in patient who required the surgical treatment.
The present study had few limitations also. Although the study was conducted for 2 years, the sample size was small and so it limited the use of statistical tests. The long-term follow-up for 1 year or more was not possible in present institution. Further study involving larger sample size and longer follow-up will be more helpful in assessing the risk factors of increase in IOP.
| Conclusion|| |
Age above 55 years, pre-operative diagnosis of adherent leucoma and aphakic eyes were major risk factors for the post-operative increase in IOP in the present study. Peak rise in IOP was reported following 2 months post keratoplasty. Post PK glaucoma in the majority of patients responded to medical treatment.
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[Table 1], [Table 2], [Table 3]