Ocular complications of silicone oil

Objective: silicone oil [SO] is an invaluable tool in the management of complex retinal detachments [RDs]. Injection of silicone oil is associated with a variety of ocular complications specially when it is kept for a long time and its removal is endangering retinal re-detachment. The objective of this study was to determine the frequencies of different ocular complications associated with silicone oil injection in our setup

Study Design: case series

Place and Duration of Study: this study was conducted at Vitreo-retina division of Al-Shifa Trust Eye Hospital, Rawalpindi from January 2014 to June 2014

Material and Methods: a total of 30 patients were included in the study who underwent pars-planavitrectomy [PPV] with silicone oil injection for complex retinal detachments. The patients who had reached between 3 months and 6 months of their postoperative period and were presenting with some complications related to silicone oil injection were included in the study. Their records were reviewed and pre-operative data were collected regarding state of the eye preoperatively. Then the post-operative complications were noted. The descriptive and analytical statistics of different variables were measured using SPSS-17.0 software

Results: out of thirty patients included in our study 23 [76.7%] were male and 7 [23.3%] were female. The mean age was 21.53 +/- 16.004 years and range was 66 years. The mean pre-operative intra-ocular pressure [IOP] was 14.0 +/- 2.150 mmHg and range 8 mmHg and the mean post-operative IOP was 24.93 +/- 13.889 mmHg and range 45 mmHg [p=0.001. The pre-operative PVR grade-C was absent in 12 [40%] patients and was present in 18 [60%] patients and post-operative PVR grade-C was absent in 24 [80%] patients and was present in 6 [20%] patients [p=0.004; McNemar test]. Band keratopathy was seen in 8 [26.7%] and corneal decompensation in 2 [6.7%] patients. Emulsification of silicone oil was seen in 14 [46.7%] patients. Rubeosisiridis was present in 2 [6.7%] patients

Conclusion: apart from other complications, raised intraocular pressure is a significant postoperative complication of eyes with silicone oil injection, so should be kept in mind because if not addressed properly it may lead to irreversible blindness in these cases

Retinal thickness and visual acuity in diabetic macular edema: an optical coherence tomography-based study

Objective: To determine the relationship between foveal [retinal] thickness and visual acuity in diabetic macular edema through optical coherence tomography [OCT] mapping software

Study Design: Cross-sectional descriptive study

Place and Duration of Study: The'Retina Clinic of Al-Shifa Trust Eye Hospital, Rawalpindi, from August 2011 to August 2012. Methodology: Eighty eyes of 68 patients with clinical diagnosis of diabetic macular edema, based on complete ophthalmic examination, were enrolled. The best-corrected visual acuity was recorded on logMar scale

OCT imaging was performed through dilated pupil by experienced operator. Foveal thickness was determined. OCT parameters of macular thickness were analysed with baseline variables including age, duration since diagnosed with diabetes, and visual acuity

Results: The mean visual acuity was 0.81 [0.2 - 1.8] logMar units. The average foveal thickness was 395.09 +/- 142.26 [183 - 825 pm]. There was moderate correlation between foveal thickness and visual acuity [r[s]= 0.574, p < 0.001], absent in those who had visual acuity worse than 1 logMar. There was a weak positive association between foveal thickness and the duration of diabetes [r[s]=0.249, p < 0.05]. There was, however, no correlation between foveal thickness and age [r[s]=0.012, p=0.919]

Conclusion: There is a moderate correlation between visual acuity and degree of foveal thickening in diabetic macular edema, hence two cannot be used interchangeably in clinical practice

Surgical and visual outcomes of retinal detachment surgery in eyes with chorio-retinal coloboma

Objective: To evaluate the anatomical and visual outcome of surgical management of retinal detachment associated with chorio-retinal coloboma

Study Design: Prospective interventional case series

Place and Duration of Study: This study was conducted at Al-Shifa Trust Eye Hospital Rawalpindi from Jan 2012 to Dec 2013

Material and Methods: Twenty one eyes [21 patients] that underwent surgery for retinal detachment associated with chorio-retinal colobomas were selected. Evaluation was done on the basis of type of intervention, final visual acuity and anatomical outcome and complications. Out of 21, 19[90.47%] eyes underwent pars plana vitrectomy with silicone oil [SO] and 2[9.52%] underwent primary scleral buckling surgery. SO was removed in 9 [47.36%] eyes at final follow up. Encircling band was placed in 12 [63.15%] eyes based on peroperative judgment of surgeon. Intra-operative lensectomy was performed in 6 [28.57%] eyes. The main outcome measures were retinal re-attachment and visual recovery. Statistical analysis was performed using "IBM statistical package for social sciences [SPSS] Statistics" [version 17.0, Chicago, Illinois, USA]. Qualitative variables were described using percentage; quantitative data were defined using mean +/- standard deviation. The pre op and post op frequency of best corrected visual acuity [BCVA] was compared using Wilcoxan Signed Ranks Test. Confidence interval was 95% [level of significance p<0.05]

Results: The mean number of operations per eye were 1.57 +/- 0.74; mean follow-up was 13.1 months [range 12-18]. The retina remained attached in 18 eyes [85.71%] at final follow-up. The post op BCVA improved significantly as compared to pre op BCVA [p< 0.01]. Mean pre op BCVA was counting fingers [CF] and mean post op value of BCVA was 3/60

Conclusion: Pars plana vitrectomy along with silicon oil tamponade for retinal detachment related to choroiretinal coloboma improves the long-term anatomical outcome however no significant improvement in visual acuity was observed

Changes in macular thickness and visual acuity after intravitreal bevacizumab injfection in patients with retinal vein occlusion

To evaluate the effect of singel Intravitreal Bevacizumab [Avastin] injection on visual acuity [VA] and central retinal thickness [CRT] in patients with macular edema secondary to branch retinal vein occlusion [BRVO] or central retinal vein occlusion [CRVO]. Prospective, non-randomized, interventional case series. This study was conducted at Al-Shifa Trust Eye Hospital Rawalpindi from March 2012 to February 2013. Twenty three patients with macular edema attributable to vein occlusion received intravitreal injection of Bevacizumab 1.25 mg. Nine patients had central retinal vein occlusion [CRVO] and 14 patients had branch retinal vein occlusion [BRVO]. Complete ophthalmic examination including best corrected visual acuity [BCVA] and optical coherence tomography [OCT] was done at base line and follow up visits. At base line mean visual acuity was Log MAR 0.73 and showed improvement to mean Log MAR 0.39 at 12 weeks after intravitreal Bevacizumab [IVB] injection. Mean CRT was 527 micro m at baseline that decreased to 274 micro m after 12 weeks of IVB treatment. Intravitreal Bevacizumab appears to result in significant short term improvement of VA and macular edema secondary to vein occlusion

Most common clinical features of age related macular degeneration in Pakistan

To document the most common clinical symptoms and signs in patients diagnosed with ARM and ARDM. Observational study. The study was conducted at Retina clinic, Al-Shifa Trust Eye Hospital, Rawalpindi. Patients with age related macular degeneration were randomly selected over a period of 6 months. A pre-tested structured questionnaire was filled by a consultant in retina clinic. Patients were asked about the presenting symptoms already enlisted in the questionnaire. The pupil was dilated till adequate retinal examination was possible and the clinical signs observed and documented. 209 eyes of 106 patients were examined. 18 were having age related maculopathy, 80 had atrophic type of ARMD and 111 were having exudative ARMD. The patients were having gradual blurring of central vision [91%], reading difficulty [28%] and metamorphopsia [9.6%] as the most common presenting symptoms. Macular drusen were the most common feature of maculopathy. Also, macular drusen were the most common clinical feature of eyes with Dry ARMD. Eyes with wet ARMD were having choroidal neo-vascular membrane [CNV] in 86% of cases and pigment epithelial detachment [PED] in rest of the 14%. There is need for making an organized screening protocol of macular degeneration for our population at risk. Every patient complaining of gradual blurring of vision and metamorphopsia should be examined for signs of ARMD. Macular drusen, hypo and hyper-pigmentation of RPE, CNV with exudation and hemorrhage or fibro-glial scar and PED must be identified on retinal examination for proper diagnosis and management of the ARMD

case with bilateral optic disc drusen causing non arteritic ischemic optic neuropathy

To report a rare case of bilateral optic disc drusen causing Non Arteritic Ischemic Optic Neuropathy [NAION]. A 60 years old male with hypermature cataract in right eye was referred for evaluation of posterior segment. Left eye showed impaired color vision with RAPD, disc swelling and peripapillary haemorrhage. On B Scan, echo free vitreous with flat retina associated with hyperechogenic shadow over the disc was seen in both eyes. Right eye after cataract surgery showed disc swelling with suspicion of optic disc drusen. CT scan of brain and eye ball and other systemic examination were normal. On the basis of B scan and clinical features bilateral optic disc drusen with NAION left eye was diagnosed. Optic disc drusen as a cause of NAION is not so common. Routine B Scan in these cases can easily differentiate from other causes of bilateral disc swelling

Ocular features, clinical profile and results of surgical intervention in a series of patients with Port Wine Stain and neurofibromatosis

To describe the ocular features, clinical profile and results of surgical intervention in a series of patients with facial port-wine stain [PWS] and neurofibromatosis [NF] in the pediatric age group. All consecutive patients having PWS and NF presenting between January 2011 and April 2012 were included. Their systemic and ocular features were recorded. Imaging study of brain and orbits was carried out where required. Appropriate surgical interventions were carried out as indicated. These included trabeculectomy, cycloablation, excision of episcleral haemangioma and vitreo-retinal surgery. Patients were followed up for complications and control of intra ocular pressure [IOP]. A total of 9 eyes of 8 patients were included. At presentation IOP in the involved eye ranged from 6 to 42 mmHg [mean 25.00 +/- 12.23]. Glaucoma was present in 6 eyes. Episcleral haemangioma was noticed in one patient, retinal detachment [RD] was seen in 2 patients. Diffuse choroidal thickening on B scan was noted in 5 eyes of patients with PWS. After applying the appropriate management option, IOP on last follow up ranged from 6 to 24mmHg [mean 13.44 +/- 5.43] in the involved eye the last follow up ranged from 6 to 24mmHg [mean 13.44 +/- 5.43] in the involved eye. The difference between IOP of the involved eyes at initial presentation and that recorded at the last follow-up was significant [p=0.005]. Patients with SWS and NF present with varied clinico-ocular profiles and therapeutic interventions are individualized according to the ocular involvement. Post operative complications after treatment of glaucoma in such patients can largely be prevented with special measures taken per-operatively

Angiographic patterns of various retinal medical diseases in Pakistan

Objective: To study the angiographic pattern of various retinal medical diseases in Pakistan

Study Design: A hospital based observational study conducted on 13,941 patients presenting at Al Shifa Trust Eye Hospital, Rawalpindi from 1991 to 2011

Subjects and Methods: A complete history of patients was taken after which patients were evaluated thoroughly by carrying out refraction and slit lamp examination followed by direct and indirect ophthalmoscopy. Olympus camera was used for fundus photography and angiography. Color fundus photographs were taken using 400 ASA or 100 ASA kodachrome films. For fundus fluorescein angiography [FFA] 5ml of 10% sodium fluorescein was injected in superficial vein of hand or forearm and recording of angiography was done using 400 ASA Agfapan films. Colored fundus angiography was also done in some patients

Results: We found that diabetic retinopathy was the most common problem in 4265[30.59%] patients followed by venous occlusion in 3415[24.49 %] patients. Age related macular degeneration was diagnosed in 2724 [19.54 %] patients. Acquired maculopathies were found in 2107 [15.12 %] and central serous retinopathy in 1659 [11.90 %] patients while 352 [2.53 %] patients had cystoid maclar edema. 544 [3.9 %] patients were diagnosed with hereditary disorders. This analysis gives us a general review of the retinal diseases in our population

Conclusion: The angiographic pattern of various retinal medical disorders in our population is quite different from many western countries. Retinal vascular disorders are the most common indication of FFA in our setup

Comparison of efficacy of Ranibizumab versus Bevacizumab in neovascular Age Related Macular Degeneration

Objectives: To compare the efficacy of two anti-vascular endothelial growth factor [VEGF] agents in sub retinal neovascular membrane [SRNVM] due to age related macular degeneration [AMD]

Study Design: Comparative, non-randomized interventional study

Subjects and Methods: The study was conducted at Al-Shifa Trust Eye Hospital in which 861 eyes of 794 patients were included. Patients in each group got 3 intravitreal anti-VEGF injections and were followed up for six months. Intravitreal dose used for Bevacizumab was 1.25 mg and Ranibizumab 0.5mg every 4 weeks. At each follow up, visual acuity and macular thickness on Optical Coherence Tomography [OCT] were analysed

Results: Total 790 patients of Bevacizumab group had the mean baseline VA of 0.9 log MAR and mean macular OCT thickness of 526 micro m. At the end of treatment, their mean BCVA AND OCT macular thickness was 0.69 log MAR and 261 micro m respectively, showing statistically significant improvement. 71 patients of Ranibizumab group had mean baseline VA of 0.7 in log MAR chart and their mean OCT thickness of macula was 416 micro m. They showed significant improvement in their mean VA and OCT thickness to 20/70 [0.55 log MAR] and 219 +/- 49 micro m respectively with improvement of 29.62%, and 89.95% respectively which was statistically significant. However, there was no significant difference between two groups in terms of final VA and side effects

Conclusion: Both Ranibizumab and Bevacizumab are equally effective in neovascular AMD. Considering the cost, bevacizumab may be the drug of choice as no serious adverse events were found

Retinal thickness evaluation in healthy eyes from north-west Punjab through optical coherence tomography

To determine the mean retinal thickness in healthy eyes from north-west Punjab through commercially available optical coherence tomography [OCT] mapping software, version 3.0, from the Stratus OCT [OCT3]. Descriptive study. Al-Shifa Trust Eye Hospital, Rawalpindi, from August 2008 to February 2009. One hundred and two eyes of 75 healthy north-west Punjabis, fulfilling inclusion criteria were enrolled from OPD of Al-Shifa Trust Eye Hospital. After informed consent, demographic detail was taken. Best-corrected Snellen visual acuity was recorded. OCT was performed by using Stratus Carl Zeiss OCT through dilated pupil by an experienced operator. The retinal thickness was divided into 9 sections and displayed as three concentric circles including a central circle at fovea [1 mm], an inner ring [3 mm] and an outer ring [6 mm], each ring being divided into four quadrants. OCT parameters of macular thickness were analysed with baseline variables including age, gender and best corrected visual acuity. The mean central foveal thickness [at foveola] was 166.30 +/- 24.95 micro m while the mean foveal thickness [in central 1000 microns] was 194.89 +/- 21.33 micro m. There was no correlation between macular thickness and either age [r=0.109, p=0.275] or gender [Eta=0.128] or best corrected visual acuity [Eta=0.234]. Reference values were determined for mean retinal thickness in healthy eyes from north-west Punjab through OCT. These measurements were upto 54-micro m higher and upto 29 micro m lower than some previously reported healthy retinal thickness values. Therefore, normative database should be determined for the population under study based on regional and ethnic differences

Low vision rehabilitation for patients with Age-related Macular Degeneration

To assess the effectiveness of low vision rehabilitation in the management of age related macular degeneration. The study was carried out at Al-Shifa Trust Eye Hospital Rawalpindi. All consecutive newly diagnosed patients of both sexes, 55 years of age and above, with observable lesions of age-related macular degeneration [AMD], presenting to the retina clinic, over a period of one year were included in the study. Patients having best corrected visual acuity less than 6/18 in the better eye were referred to the low vision clinic. During the duration of study 79 patients presenting to the retina clinic met the inclusion criteria. Lesions gradable as early AMD were found in 54 eyes and those graded as late AMD were found in 69 eyes. Twenty four [30%] patients received intra vitreal therapy with anti-vascular endothelial growth factor [Bevacizumab] +/- Triamcinolone acetonide and/or Argon laser treatment. Thirty seven [47%] patients were referred to the low vision clinic, while 18 [23%] patients were taught self-monitoring of symptoms and kept under observation. Appropriate low vision aids were used in 37 patients. Extremely statistically significant improvement in near vision was seen from mean 14M to 4M [p <0.0001] in 36 patients. Low vision aids improve residual visual function in patients of AMD, more so for near. The patients are able to continue most of the usual activity of their daily life

Neodymium: YAG laser treatment for dense premacular subhyaloid hemorrhage

Objective: To assess the efficacy of Neodymium: YAG laser membranotomy and posterior hyaloidotomy in achieving rapid intravitreal drainage of dense premacular hemorrhage and rapid visual rehabilitation

Methods: Eight eyes of eight patients had Nd: YAG laser treatment to release trapped hemorrhage overlying the macula. Two to five laser membranotomies were performed. Colored fundus photographs were taken. Patient with diabetes had panretinal photocoagulation prior to YAG laser treatment

Results: The premacular hemorrhage originated from proliferative diabetic retinopathy in four eyes, from a retinal macroaneurysm in two eyes, from leukemic retinopathy one eye and from valsalva retinopathy in one eye. Complete intravitreal dispersion was achieved in all eyes within one week with marked improvement of vision. One diabetic eye showed less improvement in vision due to diffuse dispersion of hemorrhage in the vitreous

Conclusion: Nd: YAG laser membranotomy seems helpful in rapid clearing of premacular hemorrhage and improvement of vision in certain eyes

Hypertrophic pyloroduodenal tuberculosis

Hypertrophic pyloroduodenal tuberculosis is a rare cause of Gastric Outlet Obstruction [GOO] often forgotten in the differential diagnosis of gastric outlet obstruction. Since laboratory and radiological investigations often prove inconclusive in reaching the diagnosis of hypertrophic pyloroduodenal tuberculosis, surgery has a key role in the management of hypertrophic pyloroduodenal tuberculosis. Postoperative anti-tuberculosis chemotherapy [ATT] becomes imperative for complete resolution of hypertrophic pyloroduodenal tuberculosis. This case report describes the condition and management in a young girl

Screening for diabetic retinopathy: a comparative study between hospital and community based screening and between paying and non-paying patients

Prevalence of diabetes and diabetic retinopathy varies in the population considering the background and financial status. A total of 79, 194 people more than 40 years, were screened for diabetes both in the community and eye hospital setting. Initial screening was carried out by urine dipstick followed by random blood sugar examination. A value >/= 140 mg/dl of blood sugar was considered positive for diabetes. All the diabetics were then examined for any evidence of diabetic retinopathy through indirect ophthalmoscopy in a dilated pupil by a midlevel ophthalmologist. Health education campaign at public, patient and professional level was also conducted. The results of screening were analyzed for three distinct groups; rural population, hospital based free patients and hospital based paying patients. The prevalence of diabetes was found to be 9.12%, 10.34% and 18.57% in rural community, poor hospital and affluent hospital groups respectively. The prevalence of diabetic retinopathy in the total screened population in these three subgroups was 1.92%, 2.52% and 4.42% respectively, while this prevalence in the diabetic population was 21.05%, 24.39% and 23.80% respectively. The cost per person screened was $2.6-3.4, while the cost per diabetic identified was $26-28 and the cost per patient of diabetic retinopathy identified was $108-135. The prevalence of diabetic retinopathy was two times more in the affluent hospital patients as compared to poor hospital patients or rural population. For each known diabetic, there were four previously undiscovered diabetics in the rural population, and two previously undiscovered diabetics in hospital based population

Complications associated with the use of 5000 - centistoke silicon oil after vitreo - retinal surgery

The purpose of the study was to report and compare the complication rates associated with use of silicon oil after vitreo-retinal surgery. This was a prospective hospital based study spanning over a period from January 2004 to June 2005. A total of 69 patients with different vitreo-retinal diseases were operated by a single surgeon using standard three ports pars plana vitrectomy technique and 5000-centistoke silicon oil. Depending upon the intra-operative situation, additional procedures were performed including use of an encircling band, relaxing retinotomy and use of perfluorocarbon liquids. The major post-operative complications observed were, development of cataract in 46 [85.18%] out of 54 patients, early post-operative raised intra-ocular pressure [IOP>25 mmHg] in 28 [40.57%] patients, keratopathy [including corneal edema, corneal abrasions and band keratopathy] in 15 [21.73%] patients, emulsification of silicon oil in 5 [7.26%] patients, glaucoma in 5 [7.26%] patients on final follow-up and ocular hyopotony in 1 [1.44%] patients. Retinal re-attachment in 35 [72.92%] and retinal re-detachment in 13 [27.08%] patients. Visual out-come was, improved visual acuity in 45 [65.23%] patients, preserved [un-changed] in 10 [14.49%] patients and was reduced in 14 [20.28%] patients. The use of silicon oil in vitreo-retinal surgery offers definite advantages however, its complications particularly cataract, glaucoma and kertopathy lead to worries about its use for prolonged retinal temponade

Management and visual outcome of retinal detachment caused by tennis ball trauma

To evaluate the visual outcome of surgical intervention in retinal detachment due to tennis ball injury. An interventional study Total 29 cases with retinal detachment having history of tennis ball trauma to the eye were included in this study. All patients were male of age ranging between 6 to 26 years. Of them 8 [27.58%] were children and 21 [72.42%] were of working age group. Types of retinal detachment encountered were inferior retinal detachment 17 [58.6%], sub total to total retinal detachment 11[34.5%], tractional retinal detachment 1 [3.45%] and total retinal detachment with severe PVR 1 [3.45%]. Conventional RD surgery was done in 28 cases and 7 cases required vitrectomy. endolaser, and silicone oil injection. Out of twenty nine patients included in this study 27.58% were children below the age of 15 years and 72.42% were between the ages of 16 to 30 years. All patients were male with only one female patient that was not included in the study. There was substantial improvement of vision in 24 cases and vision remained unchanged in 5 cases after they underwent vitreoretinal surgical procedures. The mean follow up period was one year. Useful vision could be achieved in most of tennis ball injury induced retinal detachment cases by surgical intervention

Refractive error study in strabismic children: results from Al-Shifa Trust, Rawalpindi, Pakistan

To assess the prevalence of refractive error and visual impairment in children with strabismus. Study design:-Hospital based prospective study. July 1995 to June 1998. A total of 1120 strabismic children between the ages of 02-l 5 years were examined to identify those having refractive error. visual acuity measurement, cycloplegic retinoscopy, ocular motility evaluation and examination of the external eye, anterior segment, media and fundus were performed in all the strabismic children. Out of 1120 strabismic children, 622 [55.54%] had esotropia, 370 [3104%] had exotropia and 128 [11.42%] had vertical strabismus.148 [13.21%] were emmetropic, 972 [86.79%] strabismic children had refractive errors. Esotropia was the most common strabismus followed by exotropia and vertical strabismus. Severe visual impairment was found in 27.30% of the strabismic children. The most common refractive error was hypermetropia followed by astigmatism and myopia. About half of all the strabismic children had amblyopia

Role of intraoperative 360 retinal endophotocoagulation in the management of giant retinal tears

To determine the effectiveness of intraoperative 360 degree retinal photocoagulation in the management of giant retinal tears [GRTs]. Departments of Vitreoretina, Al Shifa Trust Eye Hospital, Rawalpindi. From 2000 to 2004. Sixteen eyes of 16 consecutive patients with GRTs were operated at Al Shifa trust eye hospital. Eyes included in this study underwent pars plana vitrectomy, perfluorocarbon liquid injection, 360 degree retinal photocoagulation and silicone oil exchange. Retinopexy was applied to the edges of the tear through endolaser photocoagulation and extended over 360 degree to the peripheral attached retina. No scieral bijckle was placed in any of these cases. The extent of the GRT was 180 degree or greater in four eyes and 90 degree to 180 degree in twelve eyes. The lower edge of the GRT was located in the inferior quadrant in fourteen eyes. PVR was grade A in five eyes, grade B in eight eyes and grade C in three eyes. In 12 [75%] of the 16 eyes, the retina was successfully reattached after surgery and 360 degree laser photocoagulation. The silicone oil was removed after a mean period of twelve weeks. Two of the four eyes were successfully reoperated by performing relaxing retinotomies. At the end of the follow up, the retinal was reattached in 14 [87.5%] of the 16 eyes. The mean follow up period was 14 months [range 5-23 months]. The success rate of management of GRTs with pars plana vitrectomy, internal temponade and 360 photocoagulation of the retina without scleral buckle is high

Screening for diabetic retinopathy: a hospital based study of paying and non-paying patients

A descriptive study was carried out to determine that results of screening for diabetes and diabetic retinopathy amongst the paying and free hospital patients. Tertiary eye care hospital. A total of 25, 510 people over 40 years were screened for diabetes in an eye hospital setting. Initial screening was carried out by urine dipstick followed by random blood sugar examination. A value [x] 140 mg/dl of blood sugar was considered positive for diabetes. All the diabetics were then examined for any evidence of diabetic retinopathy through indirect ophthalmoscopy in a dilated pupil by a midlevel ophthalmologist. Health education campaign at public, patient and professional level was also conducted. Prevalence of diabetes and diabetic retinopathy amongst paying and non-paying hospital patients. The results of screening were analyzed for two distinct groups: hospital based free patients [poor urban population] and hospital based paying patients [affluent urban population]. The prevalence of diabetes was found to be 10.34% and 18.57% in poor urban and affluent urban groups respectively. The prevalence of diabetic retinopathy in the total screened population in these two subgroups was 2.52% and 4.42% respectively, while this prevalence in the diabetic population was 24.39% and 23.80% respectively. It was observed that the prevalence of diabetic retinopathy was two times more in the affluent urban population as compared to poor urban population. For each known diabetic, there were three previously undiscovered diabetics in urban/hospital based population