congenital hereditary endothelial dystrophy ( ched ) is a rare corneal dystrophy causing bilateral diffuse corneal clouding due to an abnormal endothelium and descemet 's membrane ( dm ) .
traditionally , ched has been managed using penetrating keratoplasty ( pkp ) ; however , pkp in children has its own difficulties .
major reasons for delaying pkp in children with ched include low scleral rigidity and positive vitreous pressure resulting in a higher rate of intraoperative complications , suture induced astigmatism and amblyopia , suture complications , need for multiple examinations under anesthesia ( eua ) , and traumatic wound dehiscence .
descemet 's stripping automated endothelial keratoplasty ( dsaek ) is currently the treatment of choice for corneal endothelial disease in adults .
advantages of dsaek over pkp include surgery in a closed system , fewer sutures and less astigmatism as well as better preservation of globe integrity and protection against trauma .
however , there are a few reports evaluating the efficacy of dsaek for ched in pediatric subjects .
herein , we report a case of ched with severe corneal clouding who underwent successful operation employing a modified dsaek technique .
a 19-year - old male was referred to our clinic with severe bilateral corneal clouding and nystagmus since early childhood .
best corrected visual acuity ( bcva ) was hand motions ( hm ) in both eyes . slit lamp examination revealed severe corneal cloudiness precluding visualization of the anterior chamber ( ac ) and iris details in both eyes [ figure 1 ] .
fundus examination and specular microscopy were not possible due to corneal edema but b - scan ultrasonography was unremarkable .
central corneal thickness ( cct ) was > 1000  using an ultrasonic pachymeter ( pachymeter sp 3000 , tomey , nagoya , japan ) .
the right eye of a 19-year - old male with nystagmus and severe diffuse corneal clouding indicative of congenital hereditary endothelial dystrophy .
considering poor visualization of the ac and the risk of lens damage , some modifications were made in the standard technique to decrease the rate of intraoperative complications .
preoperatively , topical pilocarpine 2% was used to induce miosis and decrease the risk of inadvertent lens damage [ figure 2a ] . with the surgeon sitting temporally , the corneal epithelium was removed although it did not improve the surgeon 's view of the ac .
at the 11 oclock position of the cornea , a 1 mm side port incision was created ; an ac maintainer was inserted and turned on .
a vertical incision at the corneal reference mark was made at 3 oclock using a 15 blade [ figure 2b ] .
due to poor visualization , dm was not stripped . a 100 nylon suture ( sharpoint 100 nylon , 3/8 circle needle , angiotech pharmaceuticals , inc .
usa ) was introduced into the ac with the swaged end of the needle entering first [ figure 2c ] .
it was pulled out through the temporal incision using a reverse sinsky hook by engaging the loop between the swage and the thread [ figure 2d and e ] .
a precut donor cornea was punched 8 mm in diameter using a disposable punch ( hessburg - barron punch , katena products inc , denville , nj , usa ) .
the needle was passed through the fold line at half thickness [ figure 2f ] and the knot was tied in a long loop for easy removal of the thread out of the button [ figure 2 g and h ] .
the temporal incision was then enlarged to 5 mm and the suture pull - through technique was used to insert the button through the ac with the stromal side up [ figure 2i  l ] .
the thread was cut and removed from the lenticule [ figure 2 m ] . after graft unfolding
, a large air bubble was injected into the ac to keep the graft adherent to the overlying stroma [ figure 2n ] .
partial decompression of the ac was done and the patient was positioned face up for 2 hours .
surgical technique of modified descemet 's stripping automated endothelial keratoplasty ( dsaek ) : preoperatively there was severe corneal cloudiness ( a ) , after placing an anterior chamber ( ac ) maintainer , a vertical corneal incision was made at 3 oclock ( b ) , a 10/0 nylon suture was introduced into the ac with the swaged end of the needle entering first ( c ) , the needle was pulled out through the temporal incision using a reverse sinsky hook ( d and e ) , the needle was passed through the fold line of an 8-mm donor disc at half thickness ( f ) , the thread was tied in a long loop ( g and h ) , the disk was pulled into the ac by the 10/0 nylon suture ( i - l ) , the graft was unfolded ( m ) and kept adherent to overlying stroma by injection of an air bubble ( n ) . on the first postoperative day , the graft was well centered .
the patient was given chloramphenicol eye drop 4 times a day for 1-week and betamethasone 1% eye drop every 2 hours which was tapered gradually over 1-month .
bcva at 4 months was counting fingers at 4 m and cct was decreased to 680 . due to residual corneal opacity , specular microscopy was not possible [ figure 3 ] . the same eye 4 months after dsaek shows a marked decrease in corneal edema .
conventional pkp , as the traditional treatment for ched , has a high risk of failure and complications in younger subjects
. low scleral rigidity and positive vitreous pressure may lead to devastating intraoperative complications such as suprachoroidal hemorrhage in children undergoing pkp .
postoperatively , children show more fibrin reaction . suture related problems including infection and graft rejection due to loose sutures , astigmatism and amblyopia , traumatic wound dehiscence and the need for multiple euas are the reasons for which surgeons defer pkp as long as possible in children with ched . in adults , dsaek is the treatment of choice for endothelial dysfunction .
it has higher safety and efficacy due to better preservation of globe integrity , elimination of corneal suture - related problems including astigmatism and infection , and faster visual recovery .
these advantages are especially important in pediatric patients ; however , there are only a few reports of dsaek in pediatric subjects
. positive vitreous pressure with shallow ac and phakic status of children 's eyes which increase the risk of lens damage are major concerns in these eyes .
pineda et al reported the first attempt of dsaek in a 7-year - old boy which was converted to pkp due to technical difficulty .
mittal et al reported the first successful dsaek in a 19-year - old patient with ched .
bellucci et al were the first to report successful endothelial keratoplasty in both eyes of a 3 months baby with ched .
busin et al reported successful results of dsaek in 15 eyes of 8 patients with mean age of 9 years ( range , 6 months to 30 years ) .
they performed standard dsaek using the busin glide with the 3 and 9 oclock incisions moving 1 mm superiorly to protect the lens by iris . in 6 eyes of 3 patients
owing to rapid restoration of corneal clarity in this series , they recommended the technique to be performed at an earlier age . in a study by asher et al , five ched patients with mean age of 7.8 ( range , 512 ) years underwent successful dsaek with reduced postoperative complication compared to pkp .
they used a microcapsulorhexis forceps and a light pipe to improve visualization of dm and inserted the lenticule into the ac by passing the sheet 's glide across the pupil to protect the crystalline lens .
they could not strip dm due to its firm attachment and used the busin glide and forceps to pull the disc into the ac .
although the results of dsek as an alternative to pkp for ched are encouraging , one may face several technical difficulties during surgery . due to firm adhesion of dm to the posterior stroma in cases of ched especially during the 1-year of life , dm does not peel off as easily as in older subjects and fuchs dystrophy and pseudophakic bullous keratopathy .
shallow and poorly visualized acs as well as phakic status of the eye are additional challenges during the surgery . in our patient
, we did not strip dm due to poor visibility , and did not use a busin glide to prevent accidental lens damage . instead
, a modified suture pull - through technique was employed with fewer instruments being introduced into the ac . by continued evolution and improving dsaek technique
 a 19-year - old male with congenital hereditary endothelial dystrophy ( ched ) presented with severe bilateral corneal clouding precluding any view of the intraocular structures . 
 he underwent modified descemet 's stripping automated endothelial keratoplasty ( dsaek ) technique including a suture pull - through technique to prevent lens damage . 
 surgery resulted in progressive clearing of the cornea and decreased corneal thickness . 
 visual acuity increased from hand motions preoperatively to counting fingers at 4 m after 4 months . 
 dsaek can be successfully performed in phakic eyes with ched as an alternative to penetrating keratoplasty . 
 it has the advantage of less wound problems and better preservation of globe integrity especially in children . 
INTRODUCTION
SURGICAL TECHNIQUE
DISCUSSION
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