the postoperative care has changed from admission in the hospital for several days to total ambulatory care .
european and north american studies have examined the safety and early recovery of patients and have justified this change [ 13 ] .
the less developed countries including india have also adopted this change in technique and patient care .
a nationwide or large single - center study on the safety and complications related to these changes is sparse in india .
we believe these studies will help planning the management policies of cataract surgery and finally formulate a uniform health care planning in india .
there were three objectives of this study : ( 1 ) to estimate the rate of acute endophthalmitis in a large tertiary care eye hospital in south india , ( 2 ) to correlate the events of endophthalmitis with change in surgical technique from extracapsular cataract extraction ( ecce ) to phacoemulsification and from the inpatient to ambulatory patient care , and ( 3 ) to evaluate the differential infection rate in the higher and lower socioeconomic strata of the society .
the study was done in a large tertiary care referral eye center in south india .
comprehensive and total eye care is provided to patients of lower socioeconomic group ( nonpaying patients ) at no cost to the family .
the materials for this study were obtained from the patient records of the institute after due clearance from the institutional review board .
all adult cataract surgeries ( excluding 2114 complicated cataracts following uveitis and trauma ) performed between january 1993 and december 1998 were included .
the study did not include the referred patients of postcataract surgery acute endophthalmitis operated outside the institute facilities .
all patients were operated either by institute full - time faculty or ophthalmology fellows after a sufficient period of training ( certified by the faculty ) .
apart from specific technique related to the ecce and phacoemulsification , all processes related to pre- , intra- , and postoperative care were uniform as per the institute protocol earlier published by us .
the inpatient care patients stayed overnight in the institute , and the ambulatory care patients were discharged usually within one hour of surgery .
the eye patch was removed in all patients on the first postoperative day and replaced with a plastic eye shield or a pair of protective goggles .
the first day evaluation included uncorrected and pinhole snellen acuity under standard conditions , applanation tonometry , a detailed slit lamp examination of the anterior segment , and fundus biomicroscopy using a + 78/90  d lens .
the postoperative medications included topical fluoroquinolones four times daily for two weeks and topical 1% prednisolone acetate six times daily for four weeks and tapered thereafter .
all patients were routinely instructed to report immediately should they notice / experience increased redness , pain , unusual discharge from the eye , and reduction in vision . all patients who returned with these symptoms and
were suspected to have inflammatory or infective endophthalmitis were examined in the retina - vitreous service ( td , sj , abm ) for further management as per the standards we have earlier published .
prior to december 1995 ( publication of evs results ) , all patients received immediate vitrectomy ; beginning from january 1996 , the evs recommendations for postcataract surgery endophthalmitis were followed , though surgeon - specific variations were allowed . in the pretransition period ( 19931995 ) , all patients also received intravenous antibiotics , and this was discontinued after publication of the evs results .
the collected undiluted vitreous fluid was evaluated in the microbiology laboratory for microscopy and culture ( aerobic and anaerobic bacteria and fungi ) as per the institutional protocol .
all cultures were kept at least for a period of 4 days ( 14 days when fungus was suspected ) before declaring them negative .
a positive culture was defined as confluent growth of organism(s ) at the site of inoculation on one solid medium and nonconfluent growth in one solid medium along with growth in one or more liquid media ; growth of the same microorganism in one liquid medium which was also identified in microscopy .
patients were kept admitted to the institute for a period of 3 to 5 days ( five days when patients received intravenous antibiotics ) . during this period ,
they were treated with intensive topical antibiotics , topical cycloplegic , intensive topical , and oral corticosteroids ( except in cases of suspected or confirmed fungal endophthalmitis ) .
case control analysis was done for the purpose of identifying all factors presumably associated with acute clinical endophthalmitis .
five controls per case were selected from the surgical registry amongst all cataract surgeries done in the same time period .
the control for each case was identified using the systematic random sampling strategy from the entire time period of the study .
they were systematically chosen from the chronologically sorted list of cataract surgeries done in this period .
this method of ascertaining the controls was adopted so that the effect of factors such as change in surgical technique and patient care was not lost .
the analyzed factors included the type of patient care ( inpatient and ambulatory ) , economic status ( higher and lower ) , type of surgery ( ecce and phacoemulsification ; iol and no iol implantation ) , systemic conditions ( diabetes and hypertension ) , habitat ( city limit and outstation ) , and surgeon factor ( faculty and fellow - in - training ) .
the years 19931995 were termed pretransition period , and the years 19961998 were termed posttransition period .
the transition was from the ecce and inpatient postoperative care in 19931995 to phacoemulsification and ambulatory postoperative care in 19961998 .
the 19931995 period also served as evs prepublication time , and the 19961998 served as evs postpublication time .
the incidence of acute endophthalmitis in the entire sample was compared between patient groups using fisher 's exact test .
the risk of endophthalmitis was compared between patient groups using risk ratios and their 95% confidence intervals ( cis ) .
independent factors in the case - control study were tested for significance in univariate level using fisher 's exact test , t - tests , unadjusted odds ratios , and adjusted odds ratios using logistic regression in the multivariate level .
significant factors in the univariate analysis at p < 0.15 were used for further multivariate testing .
stata-7 intercooled stata for windows 7.0 ( texas , 2001 ) was used for all statistical analyses .
in the study period 19931998 , a total of 46,095 cases of uncomplicated adult cataract extraction with iol implantation surgeries were performed23,727 ( 51.48% ) paying and 22,368 ( 48.52% ) nonpaying patients .
the transition time marked shift in technology of surgery and techniques of patient care and also simultaneously coincided with the publication of the first evs report .
in pretransition period , 20,039 patients ( paying : 10,560 ; nonpaying : 9,479 ) and in posttransition period , 26,056 ( paying : 13,167 ; nonpaying : 12,889 ) were operated for cataract . in the former period ,
all patients received ecce ( with / without iol ) and were treated as inpatients . in the later period , 80% ( 20,848 of 26,056 ) of patients
received phacoemulsification , and in 95% of instances ( 24,752 of 26,056 ) , the patients were provided ambulatory care . based on the clinical examination , acute
endophthalmitis was suspected in 62 patients , with an incidence of 0.13% ( 62 of 46,095 ) .
thirty six vitreous samples were culture positive , a rate of 58.06% ( 36 of 62 ) , and 37 microorganisms were isolated ( one sample had polymicrobial infection ) .
the interval between cataract surgery and presentation with symptoms and signs of endophthalmitis was  15  12  days .
the patient 's age ranged from 42 to 81 years ( mean 52 + 11 years ; median 60 years ) .
primary surgery was ecce in 4 ( 6.5% ) eyes , ecce and iol implantation in 42 ( 67.7% ) eyes , and phacoemulsification and iol implantation in 16 ( 25.8% ) eyes .
primary pars plana vitrectomy was done in 41 ( 66.1% ) eyes , and primary vitreous biopsy in the remaining 21 ( 33.9% ) eyes .
three patients in the vitreous biopsy group ( 3 of 21 ; 14.3% ) needed vitrectomy .
all patients received two intraocular antibiotics ( cefazoline / vancomycin + amikacin / ceftazidime ) , and the antibiotics ( culture adjusted ) were repeated in 3 patients who had received deferred vitrectomy .
sixteen of 37 microorganisms ( 43.2% ) were staphylococcus epidermidis , and five ( 13.5% ) were pseudomonas aeruginosa ( table 1 ) .
gram - positive cocci ( gpc ) grew in 64.9% instances ( 24 of 37 growths ) ; gram - negative bacilli ( gnb ) grew in 24.3% instances ( 9 of 37 growths ) .
eleven of 62 patients ( 17.7% ) in the entire series and 8 of 36 ( 22.2% ) culture - positive patients regained a final visual acuity of 20/40 or better .
thirty five of 62 ( 56.5% ) patients in the entire series and 21 of 36 ( 58.3% ) culture - proven infected eyes obtained final acuity of 20/100 or better .
the incidence of endophthalmitis was higher in the ambulatory patient care group compared to the inpatient care group , and this difference was statistically significant ( p = 0.054 ) .
this difference in the incidence of endophthalmitis rates was not observed in the higher socioeconomic group of patients ( p = 0.351 ) . the age and gender distribution of cases and controls was not significant ( table 3 ; univariate analysis ) . ambulatory patient care ( p = 0.025 ) and patients residing within the city limit ( p = 0.04 )
the low socioeconomic group of patients was a significant factor at the 10% level ( p = 0.157 ) .
the significance of patient residence in the multivariate analyses may be related to sampling variations of the case control itself . 

the interaction of socioeconomic status with type of patient care was a significant factor ( p = 0.038 ) ( tables 5 and 6 ) .
the risk of infection was higher in ambulatory patient care of nonpaying patients ( lower socioeconomic status ) compared to inpatient care ( p = 0.001 ) and compared to all paying patients ( p = 0.001 ) .
all paying patients ( higher socioeconomic patients ) and all inpatient care were not associated with a higher risk of infection .
type of cataract surgery ( ece or phacoemulsification ) systemic disease ( diabetes and hypertension ) and surgeon factor ( faculty and fellow ) did not have statistical significance in univariate analysis .
the current tertiary eye care study center in south india caters to both higher and lower socioeconomic group without change in quality of care .
the nonpaying category of patients are those who possess bpl ( below poverty line ) card issued by the state government .
being a retrospective case control study , it also ensured that any special efforts other than specified by the institute were not administered to affect a reduction of infection incidence .
nationwide surveys and large case series of postcataract endophthalmitis in different countries suggest endophthalmitis incidence from 0.06% to 0.31% [ 2 , 3 , 723 ] .
briefly , they include ecce with iol to phacoemulsification with iol and ambulatory patient care .
this has obviously saved the overall expenses both for the patient and the hospitals , without compromising the surgical outcome and the quality of care [ 2 , 3 , 710 ]
.   while the reports of safety and efficacy of the new technology and patient care are available from developed countries , similar reports are sparsely available from less developed countries .
this study has documented a higher risk of developing endophthalmitis in the ambulatory care lower socioeconomic group of patients .
important factors associated with this higher incidence may include the residential environment and health education .
poor residential environment and suboptimal health education could have a strong association with higher risk of endophthalmitis .
a tertiary - care - hospital - based study may not actually reflect the true incidence of postcataract surgery acute endophthalmitis in india , particularly when mass cataract surgery is actively advocated to reduce the back log of cataract blindness .
it is also possible that all patients of endophthalmitis , particularly from distant and rural locations , may not have returned for examination . but
this possibility is unlikely since most of the noninstitutionalized eye care facilities in india will normally refer these patients to a higher eye care center .
we excluded the endophthalmitis patients referred after cataract surgery done outside the institute facilities , so as to obtain uniform pre- and post - operative information .
the uniform system adopted in the institute also allowed us to divide the patients into higher and lower socioeconomic groups nearly accurately .
we also believe that such a large case control study involving over 46,000 patients and spanning six years probably overcomes some of the deficiencies of the study .
this study suggests that when deciding on to whom to offer ambulatory care cataract surgery and when developing policy related to such surgery , the increased incidence of endophthalmitis in lower socioeconomic class patients compared to those in higher economic categories should be considered .
since a long - term economic benefit lies in one hundred percent ambulatory care , improvement in housing , sanitation , and health education together is likely to improve the surgical outcome .
cataract is the major cause of reversible blindness , and several efforts are made to reduce the cataract blindness .
cataract surgery in itself does not decrease blindness without qualitative effort to improve quality of surgery and postoperative care .
cataract - surgery - related blindness varies from 17% to 43% in india , china and africa [ 24 , 2632 ] .
while the efforts of the governmental and nongovernmental organizations to combat reversible blindness in developing countries are commendable , education on good eye health and care of the operated eye should yield superior outcomes after cataract surgery .
an effective and assured ambulatory care will reduce the burden of housing the patients for longer period of time in a hospital .
this will also reduce employing health care personnel excess of requirement , thus providing much needed flexibility to the available resources .
the modern tools of surgery and management yield better results only when combined with healthy management strategy . in the absence of the later , the technological advancements can never be adequately exploited to advantage in developing countries .
 
 purpose . we investigated acute endophthalmitis incidence following cataract surgery vis - a - vis the current technological and postoperative care changes in higher and lower socioeconomic categories of patients in south india . 
 methods . in a retrospective case control study 
 , we analyzed 62 cases of acute endophthalmitis and 5 controls for each endophthalmitis case from 46,095 cataract surgeries done between years 1993 and 1998 . 
 the time period covered the transition of surgical technique and after care . 
 in addition , we analyzed systemic diseases , surgeon factor , habitat , and socioeconomic status . results . 
 clinical and culture positive endophthalmitis incidence were 0.13% and 0.07% , respectively . 
 differential incidence of 0.10% and 0.17% for in- and ambulatory care surgeries , respectively , was close to statistical significance ( p = 0.054 ) . 
 lower economy category ambulatory patients had higher risk of infection . 
 conclusion . 
 ambulatory cataract surgery carried additional risk for post - operative infection in lower socioeconomic group . 
 improved health education could ensure greater safety . 
1. Introduction
2. Patients and Methods
3. Results
4. Discussion