Preoperative B-Scan Ultrasonography Versus Postoperative Fundoscopy Among Mature And Hypermature Cataract In Diabetic Patients

evaluate posterior segment of diabetic patient with dense cataract preoperatively using B-scan ultrasonography. Design: A hospital based prospective observational study conducted in 202 diabetics with dense cataract, at HIMS during December2017 to May2019. Patients with ocular trauma, corneal pathology, uveitis, glaucoma, intraop complications like posterior capsular rent, iris prolapse, iridodialysis, capsular dialysis and complicated cataract like pathological myopia, retinitis pigmentosa were excluded from the study. Preoperative B-scan ultrasonography performed to evaluate posterior segment. They underwent manual SICS with PCIOL implantation under PBB. Postoperatively followed up at 1 week, vision and dilated fundoscopy to evaluate posterior segment. Fundoscopy was compared with preoperative B-scan report and the ecacy of B-scan was analyzed.


Introduction
B-scan ultrasonography is a powerful, safe, cost-effective, non-ionizing non invasive diagnostic tool for evaluating the posterior segment in eyes with opaque media caused by corneal opacities, dense cataracts, vitreous hemorrhage which due to which ophthalmic evaluation becomes di cult and least informative. 1 There are 285 million people with diabetes mellitus in the whole world. According to the WHO, there are 31.7 million people affected by diabetes mellitus (DM) in India in the year 2000 2 . Signs of diabetic retinopathy occur in 95% of type 1 diabetics and 60% of type 2 diabetics with longer duration. 3 Prevalence of diabetic retinopathy in India is 21.7%. 2 Cataract is considered as an important cause of low vision in diabetic patients and the prevalence of cataract in diabetics is 65.7% 4 and there is faster progression of cataract among them. The most common ocular complications of diabetes mellitus is cataract and other signi cant anterior segment complication include pupillary abnormalities. Posterior segment complications may include diabetic retinopathy, retinal vein occlusion, asteroid hyalosis, vitreous hemorrhage, posterior vitreous detachment, papillopathy, optic neuritis, retinal detachment and neurophthalmic disorders. In advanced diabetic eye disease, persistent vitreous hemorrhage, pre-retinal hemorrhage, tractional retinal detachment, posterior hyaloid membrane, neovascular glaucoma with rubeosis iridis may be seen. 5 Advances in cataract surgical techniques and instrumentation have generally improved the outcomes; however, surgery may not be safe and effective in certain individuals with pre-existing retinal pathology or limited visual potential. We aim to diagnose diabetic complications in the eyes with cataract using B-scan ultrasonography so that patient management strategy can be properly planned. And prior information regarding the post-operative visual prognosis can be given to the patient.  Even though the calculated sample size was 52, all diabetic patients with mature cataract presenting to our hospital during the study period were recruited the study. So the study was completed with a purposive sampling technique with 202 eyes of 202 diabetic patients with mature cataract.
The aims and objectives of the intended study were properly explained to the subjects and informed consent were taken. Data were collected as per the proforma sheet.
Ophthalmological workup was done as follows. Visual acuity, anterior segment evaluation by slit lamp bio microscopy, direct and indirect ophthalmoscopy of other eye, retinoscopy, intraocular pressure measurement using applanation tonometer, lacrimal sac syringing, keratometry and A-scan and biometric calculation of IOL power were done in all patients.
All patients diagnosed with mature or hypermature cataract were subjected for laboratory investigations like RBS/FBS and PPBS to diagnose diabetes mellitus. They were also subjected for blood investigations like HIV, HBsAg, complete blood count. Other investigations like ECG were also done for these patients.All patients who were known cases of diabetes and the newly diagnosed diabetic patients with mature and hypermature cataract were subjected for preoperative Bscan ultrasonography for the posterior segment evaluation. Technique: The patients were made to sit on the examination table. They were evaluated using ultrasound machine equipped with a linear high-frequency probe of 10MHz placed in Ophthalmology department. Contact method of examination was used. The probe was placed over the closed eyelid after application of coupling gel. B-scan images were obtained in axial, transverse and longitudinal sections. The lowest possible decibel gain to the maintenance of adequate intensity was used to optimize the resolution of images.
These patients underwent manual Small incision cataract surgery with posterior chamber intraocular lens implantation under peribulbar block. Postoperatively these patients were given the following medications-Tablet Cipro oxacin 500mg for 5days, Tablet Ranitidine 150mg for 5days, Tablet Diclofenac 50 mg for 5days, Moxi oxacin with Dexamethasone eye/drops 1 0 8 times a day for 1 week, Nepafenac e/d% 1 0 TID. Antibiotic with steroid eye drops was tapered and stopped over a period of 6 weeks.

Follow up
These patients were then followed up 1 week after cataract surgery with visual acuity, anterior segment evaluation and dilated fundoscopy using indirect ophthalmoscopy. Fundoscopic ndings were compared with preoperative B-scan ndings. Further postoperative follow ups and management are advised accordingly.

Statistical Analysis
Data was entered in Microsoft Excel and analyzed using SPSS version 22 software. Descriptive statistical analysis was done. The results were expressed in frequencies, percentage, means, and standard deviations.
Chi square test was used for categorical variables. Results with P value < 0.05 were considered as Signi cant.

Results
This study was done on 202 eyes of 202 patients attending outpatient Department of Ophthalmology at HIMS, Hassan during study period of December 2017 to May 2019.
The following observations were made in this study.
Mean age was 62.82843 with a range between 22 and 86 years of age.
Among the 202 patients, 43 (21.3%) of the patients had diabetes mellitus for a duration of less than 1 year. 76 (37.6%) of the patients had diabetes for a duration between 1 and 5 years. 58 (28.7%) of the patients had diabetes for a duration between 5-10 years. 21(10.4%) of the patients had diabetes for a duration between 10-20 years. 4 (2.0%) of the patients had diabetes for a duration more than 20 years (table 2).

Discussion
The present study was conducted in 202 eyes of 202 diabetic patients with mature cataract who were willing to undergo cataract surgery attending out patient Department of Ophthalmology, at HIMS Hassan.
Henricsson et al 13 analysed DR before and after cataract surgery in 70 patients and concluded that the patients with PDR, obtained good visual acuity, better than in most previous studies. Poor glycemic control was found to be an important factor for the progression of diabetic retinopathy after cataract surgery.
Our study showed, among the 129 patients with normal B-scan, 97 (75.2%) had normal fundus with no DR changes and 25% of the patients had signi cant DR changes which included 5(3.9%) patients with mild NPDR, 19(14.7%) patients with moderate NPDR, 4(3.1%) patients with severe NPDR, 4(3.1%) patients with CME (P < 0.001). This was statistically signi cant. These 25% of the patients are the reason for explaining the guarded visual prognosis.
Among 6 patients with RD on B-scan, 3(50%) had ADED, 3(50%) had PDR. One patient with asteroid hyalosis + VH on B-scan had moderate NPDR with PVD. Among B-scan is helpful in identifying the structural abnormality of vitreoretinal complex. However, all normal Bscan picture does not mean the patient will have 6/6 vision postoperatively because signi cant percentage of patients can have DR changes and macular edema which is the major cause for low vision postoperatively. These macular edema/DR changes cannot be detected preoperatively with B-scan. Hence, any diabetic patient with dense cataract cannot be guaranteed with good vision. Thus, guarded visual prognosis has to be explained to all the diabetic patients with mature and hypermature cataract preoperatively.
Conclusion B-scan ultrasonography is a valuable diagnostic tool in evaluation of posterior segment in case of opaque media. B-scan among diabetic patients with mature cataracts was found to be normal in 63.9% of the patients. 24.8% had age related vitreous changes like synchisis, incomplete Posterior Vitreous Detachment, complete PVD and Asteroid hyalosis. Only 11.3% of the patients had Proliferative diabetic Retinopathy pathologies like Vitreous hemorrhage and Retinal detachment.
Though B-scan is effective in anatomical evaluation of posterior segment and helps in assessing the approximate visual prognosis, among the patients with normal B-scan picture, postoperative fundoscopy was normal in 75.2% patients and postoperative fundoscopy showed DR changes and macular edema in 24.8% of the patients with normal B-scan. These ndings could be the major cause for low vision postoperatively. Thus, guarded visual prognosis has to be explained to all the diabetic patients with mature and hypermature patients preoperatively.