Year : 1997 | Volume
: 45 | Issue : 3 | Page : 163--168
Indications for penetrating keratoplasty in India
L Dandona, K Ragu, M Janarthanan, TJ Naduvilath, R Shenoy, GN Rao
Public Health Opthalmology Service, L.V. Prasad Eye Institute, Hyderabad, India
Public Health Opthalmology Service, L.V. Prasad Eye Institute, Hyderabad
Indications for penetrating keratoplasty (PK) in the developing world from a large series are not well documented. This study was done to evaluate the indications for PK in a major eye care institution in India. The records for a consecutive series of 1,964 PKs were analysed and multiple logistic regression was used to study the effect of age, socioeconomic status and sex on the indications for PK. The indications for PK were corneal scarring in 551 (28.1%) including adherent leukoma in 147 (7.5%), regrafts in 336 (17.1%), active infectious keratitis in 239 (12.2%), aphakic bullous keratopathy in 231 (11.8%), pseudophakic bullous keratopathy in 209 (10.6%), corneal dystrophies in 165 (8.4%) including Fuchs«SQ» dystrophy in 23 (1.2%), keratoconus in 118 (6%), and miscellaneous in 115 (5.9%). The odds that the patient belonged to lower socioeconomic status were significantly higher if the PK was done for active infectious keratitis (odds ratio 2.73, p<0.0001), corneal scarring (odds ratio 1.72, p=0.0009) or regraft (odds ratio 1.44, p=0.047). Corneal scarring, including adherent leukoma, and active infectious keratitis are relatively more common indications whereas keratoconus, pseudophakic bullous keratopathy and Fuchs«SQ» dystrophy are less common indications for PK in India than reported from the developed world. Indications for PK which carry a poorer prognosis for graft survival are relatively more common in India than in the developed world.
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Dandona L, Ragu K, Janarthanan M, Naduvilath T J, Shenoy R, Rao G N. Indications for penetrating keratoplasty in India.Indian J Ophthalmol 1997;45:163-168
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Dandona L, Ragu K, Janarthanan M, Naduvilath T J, Shenoy R, Rao G N. Indications for penetrating keratoplasty in India. Indian J Ophthalmol [serial online] 1997 [cited 2021 Oct 23 ];45:163-168
Available from: https://www.ijo.in/text.asp?1997/45/3/163/15018
Corneal diseases are a significant cause of visual impairment and blindness in the developing world. Penetrating keratoplasty (PK) offers hope for visual rehabilitation in many such cases. There are many recent reports about the indications for PK in the developed world, but to our knowledge, recent information regarding this aspect on a large series of patients is not available from the developing world. The purpose of the present study was to evaluate the indications for PK at our institution which is a major referral centre in the Indian sub-continent for the treatment of corneal diseases. It was felt that these data would suggest the trend for the distribution of indications for PK in the Indian sub-continent, and would enable comparison with the indications for PK reported from the developed world.
Materials and Methods
The patient records for all 1,964 PKs done at the L.V. Prasad Eye Institute, Hyderabad, India from July 1987 to October 1995 were reviewed retrospectively.
The indications for PK were divided into 8 large categories which were further subdivided into smaller sub-categories [Table:1]. The effect of age, socioeconomic status and sex on the distribution of these indications was studied. At our institution, assessment of the economic status of each patient is carried out to determine if the patient can pay for the services. All the services are provided at no cost to patients who are unable to pay. For the purpose of the present study, these non-paying patients were considered as having lower socioeconomic status, and those able to pay were considered as having higher socioeconomic status. The patients were divided into age groups of <50 and ≥50 years to study whether the indications for PK differed for these two age groups.
Multiple logistic regression was used to determine the effect of age, socioeconomic status and sex on the various categories of indications for PK. This multivariate model determined the effect of each of these three variables after controlling for the other two variables. Of the patients who had PKs done in both eyes, only one randomly chosen eye was included in this model in order to eliminate the error in statistical inference that could arise due to correlation between two eyes of the same patient. Also, only the first regraft was included in this model since inclusion of more than one regraft for an eye would have violated the assumption of this model that the observations within a category should be independent of one another.
The distribution of indications for PK in this series is shown in [Table:1]. A total of 1,964 PKs were done on 1,632 patients, including 1,128 (69.1%) males and 504 (30.9%) females. Ninety-six of these patients had PKs done in both eyes. The age at which PKs were done ranged from 7 days to 90 years, and both the mean and median values for age were 40 years. Corneal scarring was the most frequent indication for PK, 551 (28.1%) cases. Among the 551 case of corneal scarring the aetiologies were keratitis in 278 (50.5%), trauma in 116 (21.0%), chemical injury in 9 (1.6%), trachoma in 7 (1.3%), and unspecified in 141 (25.6%). Adherent leukomas, cases in which the iris was incarcerated in the corneal scar, comprised 147 of the 551 (26.7%) cases of corneal scarring.
Failed corneal grafts requiring regrafting constituted 336 (17.1%), active infectious keratitis 239 (12.2%), aphakic bullous keratopathy 231 (11.8%), and pseudophakic bullous keratopathy 209 (10.6%) cases of PK. Of these cases of pseudophakic bullous keratopathy, 85 (40.7%) had anterior chamber intraocular lens of the iris-claw type (Worst), 52 (24.9%) had anterior chamber intraocular lens other than iris-claw type, and 72 (34.4%) had posterior chamber intraocular lens.
Corneal dystrophies were the indication for PK in 165 (8.4%) cases. The two most common corneal dystrophies requiring PK were macular dystrophy, 44 out of 165 (26.7%) cases, and congenital hereditary endothelial dystrophy, 40 (24.2%) cases. Fuchs' dystrophy was a relatively infrequent cause for PK, 23 of the total 1,964 (1.2%) cases. It made up 13.9% of the cases of corneal dystrophy for which PK was done.
Keratoconus was the indication for PK in 118 (6.0%) cases done at our institution. Miscellaneous indications made up the remaining 115 (5.9%) cases, including 22 (1.1%) congenital conditions other than congenital glaucoma and congenital corneal dystrophy.
Of the total 1,964 PKs, 1,218 (62.0%) were done on patients <50 years of age and 746 (38.0%) on patients ≥50 years of age. 1,363 (69.4%) PKs were done on males and 601 (30.6%) on females. Of the total PKs 1,310 (66.7%) were done on patients belonging to the higher socioeconomic status and 654 (33.3%) on those in the lower socioeconomic status.
The multiple logistic regression analysis showed that age, socioeconomic status and sex had significant effect (p<0.05) on some categories of indications for PK as shown in [Table:2]
Penetrating keratoplasty can visually rehabilitate many of those who suffer from blindness or visual impairment due to corneal diseases. The prognosis of the outcome, however, is dependent on the pathology responsible for causing corneal blindness or visual impairment., The purpose of our study was to document the indications for PK at our institution which is a major referral centre for the treatment of corneal diseases in the Indian subcontinent. The number of PKs done currently at our institution is amongst the highest for any institution in the developing world. Since no recent data about the indications for PK in a large series is available from the developing world, our study was expected to provide this information.
We found that corneal scarring was the most common indication for PK, (28.1%) of the cases. Keratitis accounted for 50.5% of this corneal scarring, trauma accounted for 21.0%, and aetiology was undetermined in 25.6% of cases. The majority of the cases with unspecified aetiology for corneal scarring are thought to be due to untreated keratitis. Corneal scarring as a sequela of trachoma was rare, making up only 1.3% of the cases of corneal scarring undergoing PK. Adherent leukomas, defined as cases in which the iris was incarcerated in the corneal scar, made up 26.7% of the cases of corneal scarring. Another important feature of our series was that 12.2% of the total PKs were done for active infectious keratitis. The two groups of corneal scarring and active infectious keratitis together suggest that keratitis of various aetiologies was responsible for about 34% of the PKs in our series, making it the single largest indication for PK in the developing world. This may be indicative of several problems prevalent in the developing countries related to availability, accessibility and affordability of eye care often leading to delayed diagnosis of corneal infections and consequent corneal opacification.
As compared with our study, the proportion of PKs done for corneal scarring has been reported to be less in the developed world.[2-11] For majority of the large series reported from the developed world for which active infectious keratitis could be determined as an indication from the classification presented, this category of indication for PK made up a lower proportion than found in our study.,,,,,
Regrafts made up 17.1% of all PKs done at our institution. This is comparable to the higher end of the range reported from the developed world where regrafts have been reported to make up 6.6% to 18.2% of the indications for PK.
Aphakic and pseudophakic bullous keratopathy made up 11.8% and 10.2%, respectively, of all cases of PK done at our institution. Pseudophakic bullous keratopathy has been reported to be the leading or the second most common indication for PK in the developed world, accounting for 17.0% to 38.6% of the PKs with a median value of 23.0% in the recent reports., In our series, pseudophakic bullous keratopathy was the second most common indication for the patients ≥50 years of age, comprising 22.9% of the PKs in this age group, but for all the patients combined it made up only 10.2% of the PKs. In our study, aphakic bullous keratopathy was slightly more frequent than pseudophakic bullous keratopathy. This is in contrast with the developed world where aphakic bullous keratopathy is a much less frequent indication for PK than is pseudophakic bullous keratopathy in the recent reports. This could be due to the fact that a large proportion of cataracts in India are still removed with the intracapsular technique without implantation of intraocular lens, in contrast to the developed countries where extracapsular cataract extraction with intraocular lens implantation is the standard practice. In addition, the quality of cataract surgery in India suffers from problems related to infrastructure and manpower training. This phenomenon is quite reflective of the situation in most developing countries.
Fuchs' dystrophy accounted for only 1.2% of the cases undergoing PK in our institution. In the developed world, Fuchs' dystrophy makes up a higher proportion of the indications for PK, ranging from 4.4% to 19.5% with a median value 10.4% in the recent reports. On the other hand, the other corneal dystrophies, comprising 7.2% of the PKs in our study, made up a higher proportion than that reported from the developed world.
Keratoconus was the indication for PK in 6.0% of the cases in our study. The large series from the developed world have reported that keratoconus makes up a higher proportion of the indications for PK, ranging from 7.0% to 31.0% with a median value of 17.1%. In four of these reports, keratoconus was the leading indication for PK.,
We found in our study that the odds of being <50 years old were significantly higher if the PK was done for corneal scarring. This could be due to several reasons: (i) corneal scarring occurs more often in patients <50 years old; or (ii) that among the patients with corneal scarring those <50 years of age seek medical care more often; or (iii) that the increase in the proportion of aphakic and pseudophakic bullous keratopathy in patients ≥50 years of age brings down the relative proportion of corneal scarring as an indication for PK in this age group; or a combination of these three reasons.
The odds that the patient belonged to lower socioeconomic status were significantly higher if the PK was done for corneal scarring, active infectious keratitis or first regraft. This implies that patients with lower socioeconomic status may be more prone to corneal scarring and active infectious keratitis, and that they may have more graft failures either due to poorer compliance with post-operative care or due to a higher proportion of poor prognosis cases for PK to begin with. The significantly higher odds that the patient belonged to higher socioeconomic status if the PK was done for pseudophakic or aphakic bullous keratopathy may be because patients with higher socioeconomic status are more likely to get cataract surgery done than those with lower socioeconomic status, or that the latter seek medical care less often for aphakic and pseudophakic bullous keratopathy, or a combination of these two reasons. The reason for the significantly higher odds that the patient belonged to higher socioeconomic status if the PK was done for keratoconus may also be for similar reasons.
The significance of the significantly higher odds that the patient was female in our study if the PK was done for corneal dystrophies is not clear.
The leading indication for PK in our series was corneal scarring unlike the developed world where pseudophakic bullous keratopathy and keratoconus are the leading indications for PK.[2-11] Keratoconus has an excellent prognosis for graft survival after PK; pseudophakic bullous keratopathy and Fuchs' dystrophy have a fair to good prognosis for graft survival; corneal scarring with vascularization or adherent leukoma has a poor prognosis for graft survival, and active infectious keratitis has a very poor prognosis for graft survival., It appears from our study that indications for PK that have a relatively poorer prognosis for graft survival make up a higher proportion of PKs done in the Indian sub-continent than in the developed world.
The patients undergoing PK in our series were younger than those in the series from the developed world.,,, Blindness or visual impairment due to corneal diseases in younger patients in the developing world is likely to have a worse socioeconomic impact if visual rehabilitation is not forthcoming. The younger age of patients in the developing world requiring PK, and the higher proportion of indications for PK with poorer prognosis for graft survival in the developing world, suggest that more emphasis be given to proper training of corneal surgeons and quality eye banking in the developing world in addition to implementing effective preventive strategies to reduce the occurrence of corneal blindness.
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