Complication Prevention of Posterior Capsular Rupture using Image Processing Techniques

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1 Poceedings of the Wold Congess on Engineeing 01 Vol I, July 4-6, 01, London, U.K. Complication Pevention of Posteio Capsula Ruptue using Image Pocessing Techniques A. Ektesabi, Membe IAENG,IEEE, A. Kapoo Abstact In ecent yeas, biometics eye detection methods have become popula tools of significance. The exact eye localization technique is impotant fo analysis, and has diect effect in the subsequent steps of nomalization, featue extaction and matching. In this pape, afte consideing meits and demeits of many advanced epoted techniques, while keeping in mind, the equied fast pocessing esponse time of detection to pevent Posteio Capsula Ruptue, amalgamates technique has been poposed to obtain a pecise, fast and obust method in localizing diffeent segments of the eye, in paticula sepaation of the pupil, iis and sclea. On the contay to the majoity of the cuent available pocedues which make assumptions about ciculaity o elliptically shape of the iis and pupil, this poposed method aims to captue exact boundaies of these segments while consideing minimal detection time. The technique has been intended to be used as pat of a complication pevention pocedue duing eye sugeies. The esults of the above studies indicate the effectiveness of the suggested pocedue in eal time opeation. Keywods Cataact sugey, PCR, Localization, Pupil detection, Iis bounday detection R I. INTRODUCTION RECENT advances in biometics technology have shown geat success fo veification and identification puposes. This technology has aimed to captue the biological featues o behavioal chaacteistics of the examined subject [1]. Amongst the divese and widely used biometics techniques, those detecting the biological featues of iis ae most pomising and the success has been ecognized by all in this field [1-4]. The fist eliable iis ecognition system was intoduced by J. Daugman in 1993 [5]. Since then many new appoaches have been poposed, aiming to impove the accuacy level and the esponse time. Despite the vaiations in the suggested methodologies, in majoity of cases the pocedual steps included segmentation, nomalization, featue extaction and matching [6]. Fom this, it can be suggested that the fist and most impotant step in the iis ecognition is to identify and segment diffeent featues of the eye, in paticula the iis. Theefoe, it is only in the case of high Manuscipt eceived Mach 1,01; evised Apil 1, 01 A. Ektesabi, PhD candidate, Faculty of Engineeing and Industial Sciences, Swinbune Univesity of Technology, John Steet, Hawthon, Austalia, 31 ( amotamedektesabi@swin.edu.au ). Pofesso A. Kapoo, Associate Dean Reseach, Faculty of Engineeing and Industial Sciences, Swinbune Univesity of Technology, John Steet, Hawthon, Austalia, 31 ( akapoo@swin.edu.au ). pecision in the localization step that eliable and accuate esults can be obtained in the subsequent steps. Fig. 1. Impotant featues in the eye pupil, iis and sclea Fo the pupose of this study, image pocessing concepts, simila to those used in biometics iis ecognition systems ae poposed to be used on video ecodings captued duing eye sugeies to extact impotant featues including the iis, pupil and sclea, as shown in Figue 1. The identified featues ae then analyzed. This eal time analysis povides feedback to the sugeon and in the case of a complication an alam system would infom the opeato to stop and evise the following steps in the sugical pocedue. This is the fist time this appoach has been poposed in the field of ophthalmology. So fa thee have been significant impovements on instumentations as well as sugical pocedual methodologies but none have been able to assist the sugeon diectly inta-opeatively. This study aims to povide eal time assistance to both expeienced and less expeience sugeons and esidents duing the sugey. It is possible to apply this concept to diffeent ophthalmological sugical pocedues. In this case, the studies condition is cataact. Cataact is a condition, known as opacification of the lens, whee the potein stuctues of the lens ae denatued, causing blued vision in patients [7]. Studies pefomed by the Wold Health Oganization (WHO) indicate that 48% of the blindness in the wold is caused by cataact, with majoity living in the developing counties. The global causes of blindness and the affected population in the wold is illustated in Figue [8]. Moeove, cataact is an age elated condition [9] and so with the continuous incease in an oveall life expectancy of the wold population, the need to pevent and teat this has become of geat significance. Peventing the fomation of cataact has poven to be difficult with today s eveyday life style. The studies indicate that nealy eveyone would equie the need fo sugey at

2 , July 4-6, 01, London, U.K. Fig.. Global causes of blindness and the affected population in the wold some stage of thei lives [9]. Howeve, cetain factos have poven to be successful in educing the pobability of contacting cataact. These include a healthy life style and diet, well economic and financial status, shot tem exposue to UV lights and egula visits to the optometists [10-1]. The most common teatment fo cataact is sugey. Cataact Sugeies, have been pefomed ove centuies, oiginating back to 800 BC [1], whee they used to implement a method known as couching to dislodge the lens into the posteio segment of the eye without any lens eplacing the natual lens of the eye. It was not until the 0 th centuy when Haold Ridley intoduced the use of Inta- Ocula Lenses (IOL). Since then the common used techniques wee the Exta-Capsula Cataact Extaction (ECCE), Inta-Capsula Cataact Extaction (ICCE) and most ecently the Phacoemulsification was used fo the sugey. Fo the pupose of this study, the data is obtained fom the phacoemulsification pocedue. Despite the significant impovements in sugical instumentations and pocedues, cetain complications might occu inta-opeatively, including Posteio Capsula Ruptue (PCR), Cystoid Macula Edema, Endophtalmitis and Retinal detachment [13-16]. The most common inta-opeative complication is PCR with the aveage ate of 4.8% [17]. A male patient at the age of 75, who cannot lie flat and has conditions such as diabetic etinopathy, viteous opacities, white cataact, glaucoma, pseudoexfolation, small pupil size, axial length geate than o equal to 6.0 mm, the use of the α-blocke doxazosin is most likely at isk [18]. Some of the post-opeative effect of PCR occuence is an incease in the ecovey time of time of the patient as well as side effects on the oveall visual outcome. This is due to the highe chance of induced astigmatism [1, 13]. Despite the low pecentage of occuence of PCR, due to the lage numbe of sugeies pefomed yealy, the numbe of patients affected by this complication is significant. Hence an impovement in the sugical pocedue would have geat impact on lives of patients, and also the associated costs and esouces fo the sugeies would be geatly educed. In section two, some of the most commonly used biometic techniques and pocedues ae examined. This is then followed by the poposed technique and pocedue fo PCR pevention in section thee. Lastly the esults ae discussed and the impotance and advantages of this technique is illustated in the conclusion. II. CURRENT DETECTION TECHNIQUES AND PROCEDURES Significant impovements in the methodology of iis localization have been pefomed in the field of biometics. Seveal of these techniques have been examined and two of the most pominent woks in this field ae pesented. A. Daugman Daugman [5] use of integal diffeential opeato (3), to detect cicula edges by use of maximum gay level contast between the two neighboing sections, has poven to be successful in many cases. The poposed opeato (1) consists of the integal opeato (3) and a smoothing Gaussian filte (). max G x, y, z x, y, z I x, y ds 1 G e () Ix, y ds (3) x y z,, Whee, the integal opeato has the adius in the x, y coodinates. B. Wildes Cicula edge detecto followed by the Hough Tansfom was the poposed technique by Wildes [3]. This method is based on the optimization technique (4) and has high computational costs. (1)

3 , July 4-6, 01, London, U.K. n n g, n 1 g g g (4),,, Whee, the gadient of the nomalized image at,is g,. III. PROPOSED TECHNIQUE To detect PCR, minute vaiations in the eye ae to be detected. The key to detect these changes duing the sugey is pecise detection and analysis of the pupil and iis. Figue 3, indicates the steps involved in the image pocessing steps, as well as the oveall aim of the poject. A. Factos to conside Fig. 3. Poposed pocedue Pio to any implementation, cetain factos should be kept unde consideation. Fistly, befoe to the sugey pocedue, the patient must undego health checks. Cetain infomation obtained at this point ae cucial and to be noted by the sugeon. Additionally, some of the obtained eadings can be helpful in the intepetation of the esults and so the detection of the complication. Futhemoe, fo the pupose of this study, the accuacy of eadings is vey impotant. Theefoe, the exact, nonelliptical boundaies of both pupil and iis wee to be detemined. As a esult, methodologies involving cicula o elliptical appoximations wee ignoed. Moeove, this identification should occu in eal time and the feedback should infom the sugeon of the possibility of complication befoe it occus. As a esult, the computational time fo the detection should have been kept to be minimal. This can be done in two ways, one is to apply the image pocessing techniques which ae less computationally costly and secondly by educing the factos to be taken unde consideation while doing the analysis. One of which includes, ignoing of eyelashes and eyelids as claps ae used duing the sugey to keep the eyes open. Additionally, the head is kept steady duing the sugey and so the possible noise caused by head movement can be ignoed. Howeve, since in the majoity of cases the patients ae unde local anesthetic, exta movements of the eye ae expected to be seen duing the sugey and should be taken unde consideation while intepeting the data. B. Image Acquisition The foemost step in any image pocessing analysis is to captue high quality images with good esolution. The obtained images in this case, should be captued fom the video camea ecoding the sugey. Hadwae filtes ae placed, to educe the noise caused by minimal motion. The use of illumination compensations is also suggested to educe the effect of lighting vaiations duing the sugey. C. Image Manipulation To educe the pocessing times, the RGB images ae to be tansfomed to gay level images. The unwanted egions in the images ae emoved by softwae filteing. D. Iis and pupil Localization Thee ae seveal techniques which can be implemented to localize the iis and pupil. Howeve, the accuacy of these techniques and thei pocessing times should be consideed. To impove the accuacy of the detection, the two diffeent pocedues ae chosen and un simultaneously. Since they ae unning concuently, the pocedual time will not vay significantly to those of a single technique being un by individually. E. Nomalization In this stage filtes ae implemented to emove the noises in the image. Likewise, the unwanted eigns, such as the sclea can be emoved as well, educing the pocessing steps fo the following stages. F. Featue Extaction At this stage the equied special featues of the iis and pupil ae extacted and ae taken fo futhe analysis. G. Masks Masks ae ceated, captuing the aeas of inteest. The two sepaate implemented pocedues each ceate thei own mask. These two masks ae then combined, foming a single mask, which can then be taken to the next stage of the pocedue.

4 , July 4-6, 01, London, U.K. H. Matching and Intepetation Matching the esults occus by compaing each individual masked image with those of peviously complicated situations. If duing this compaison the esults match those of the complicated cases, the alam would sound off, and then the esults ae displayed. It is then that the sugeon is equied to stop and evise the sugical pocedues being pefomed. In the case whee no complication is obseved, the esults ae displayed diectly and the sugey continues as planned. IV. RESULTS AND DISCUSSIONS To obtain usable data and to maximize the detection accuacy, hadwae filteing is used in this pape. This educed the effect of motion and light eflection on the suface of the eye. The images have been pe-pocessed befoe segmentation. This included sampling and softwae filteing. The images wee sampled in ode to educe the computational time. Futhemoe, to educe distubances caused by motion and laminations softwae filteing wee adapted. In the segmentation stage, binay and gay scaled images wee used to impove the computational time. In this study, total eye detection was not of inteest, only the pupil and iis have been consideed. Failue in ealy detection of PCR could lead to catastophic esults in eal time pocessing of the data duing the sugey. This study shows that the poposed method can be used fo exact detection of deviations leading to PCR, by pompt ecognition of any vaiation in shape of the segments. As mentioned ealie, diffeent localization techniques can be implemented. Since the detection time has a significant ole in eal time captuing of featues, simple but pecise techniques ae of inteest. In this case, fo the sepaation of iis and pupil boundaies, the two methods of thesholding [1] and active contou pocedue [] wee used. Each of the above two techniques, would povide good estimation fo the inteested boundaies. In the poposed system by meging the two techniques, enhancement of the final accuacy of the detection was obseved. Hence, the esults obtained showed simila outcomes of each technique, but the two masks wee slightly diffeent and so the combinations of the two masks wee used to minimize the final eo in the matching and intepetation step. Simultaneous pocessing and implementation of the two methods, educed the oveall detection time, almost equal to time taken by each method. Though, the oveall detection time was simila to each, but by combing them, the pecision of detection was impoved significantly. The measued time of this pocedue was less than one second, which is simila to epoted techniques so fa but with highe accuacy in detection. This suggests the possibility of detecting an eo and esponding to it within an appopiate time, which in tun is a novel application of the high speed image pocessing technique in PCR detection duing opeation. V. CONCLUSION The study is aimed to pedict the possibility of detecting PCR, using image pocessing techniques. The use of cuently epoted techniques in the field of biometics, in paticula iis localization has been suggested fo captuing the equied featues of the eye, specifically the iis and the pupil. To impove the accuacy of the localization, integation of two o moe techniques is suggested to be un simultaneously. The combined detected featues ae then compaed with the pevious cases of PCR, in ode to help sugeons to pedict the occuence of such complication duing the sugey. Cuently the detection occus in less than one second, with the aim to impove on this, in the nea futue. REFERENCES [1] W. T. Lin, et al., "Fast and obust iis ecognition," Imaging Science Jounal, The, vol. 57, pp , 009. [] C. H. Daouk, et al., "Iis Recognition," pesented at the IEEE Symposium on Signal Pocessing and Infomation Technology, Maakesh, 00. [3] R. P. 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