Screening Examination for Retinopathy of Prematurity with Dual Parameter Protocol

So far most screening protocols for retinopathy of prematurity (ROP)have used a single parameter such as chronological age or postconceptional age. We attempted to test a screening protocol for ROP using dual parameter, chronological age and postconceptional age, to determine whether it could reduce the number of screening examinations safely.We retrospectively reviewed medical records of 23 infants (43 eyes)who had undergone laser treatment for threshold ROP.Mean gestational age at birth was 28 weeks and mean birth weight was 1055 gms.The mean age at which the study infants reached threshold ROP was 10 weeks in chronological age and 38 weeks in postconceptional age.Screening examinations as early as chronological age of 7 weeks or postconceptional age of 35 weeks could detect all threshold ROP while reducing the number of unnecessary early examinations.

Short-term Results of Laser Photocoagulation for Juxtafoveal/Extrafoveal Choroidal Neovascularization

To evaulate the closure and recurrence rate of laser treatment for juxtafoveal and extrafoveal CNV with well-defined boundary, we studied 15 eyes of 15 patients that could be followed up for at least 1 year. The follow-up ranged form 12 to 31 months(mean, 17.1 months). Three and six weeks after laser treatment, all neovascularization was obliterated. Eight months, after laserphotocoagulation was obliterated. Eight months, after laser photocoagulation there was one recurrence in juxtafoveal CNV. In7 of 10 laser-treated eyes in classic, extrafoveal CNV, visual or more in three eyes. Of 5 laser-treated eyes in classic, juxtafoveal CNV, visual acuity had changed by no more than 2 lines in 3 eyes and decreased by 2 or more lines in 2 eyes. The short-term results of laser treatment for classic CNV were good, but long-term evaluation is required.

Surgical Results of the Uncomplicated Giant Retinal Breaks

The surgical success rate for retinal detachment caused by giant retinal breaks was very low in the past because of its frequent association with proliferative vitreoretinopathy and inverted retina I flap. Recently advances in vitreoretinal surgical techniques as well as introduction of perfluorocarbon liquid result in good surgical results. Eleven eyes with uncomplicated retinal detachment from giant retinal breaks underwent vitrectorny. A special effort was made to remove as much vitreous gel of the vitreous base as possible. Lensectomy or encircling was performed, when needed. Inverted retinal flap was unfolded using perfluorocarbon liquid. After laser ph/otocoagulation, internal tamponade was performed with C3 F8 gas or silicone oil. Postoperatively, we achieved anatomical success in all eleven eyes and favorable visual acuity of better than 0.4 in nine eyes(81.8%). We obtained good surgical results for uncomplicated giant retinal breaks using meticulous vitreous base dissection and perfluorocarbon liquid. Removal of crystalline lens or scleral buckling is not always needed in this complex retinal detachment surgery.

Pseudophakic/Aphakic Retinal Detachment Surgery Using Scleral Depression Technique

In aphakic/pseudophakic retinal detachments, difficulty in visualizing the peripheral retina and perhaps higher incidence of proliferative vitreoretinopathy result in lower success rate than phakic retinal detachment. We performed pars plana vitrectomy on 20 eyes with aphakic/pseudophakic retinal detachment. In most cases, we combined scleral bucking or encircling procedure. Using scleral depression technique, we found retinal breaks, dissected the vitreous base meticulously, and removed the vitreoretinal tractions. Intraoperatively, we were able to find retinal breaks in 12 eyes in which retinal breaks were not identified preoperatively, and identify additional retinal breaks in 3 of the remaining 8 eyes. We obtained anatomical success in all eyes and favorable visual acuity of better than 0.025 in 16 eyes (80%). These results suggest that finding all retinal breaks and removing vitreoretinal tractions are directly related to the improvernent of the surgical results.

Complications of Vitrectomy for Proliferative Diabetic Retinopathy: Incidence and Management

More intraoperative and postoperative complications of diabetic vitrectomy may result in poor visual prognosis. Sixty eye (49 patients) underwent vitrectomy for complications of proliferative diabetic retinopathy. Iatrogenic retinal breaks occurred in 6 (10%) of 60 eyes. Postoperative vitreous emorrhage was complicated in 13 (21%) of 60 eyes. Postoperative vitreous hemorrhage cleared spontaneously in one eye. Fluid-air exchange alone was successful in clearing the vitreous cavity in 4 eyes. Two eyes in which clearing does not occur in the postexchange period underwent repeated vitrectomy. Remaining 6 eyes required repeated vitrectomy. Choroidal effusion occurred in 4 eyes (7%) and resolved spontaneously within one week. Neovascular glaucoma occurred in 4 eyes (7%) and was treated with glaucoma implant surgery in 2 eyes, trabeculectomy with Mitomycin C in 1 ye, and cyclophotocoagulation in 1 eye. Retinal detachment developed postoperatively in 3 eyes (5%) and was treated successfully. Corneal epithelial defect persisting more than one week was present in 2 eyes (3%). Accidental mechanical lens damage occurred in one eye. The anatomical success rate was 98% (59 eyes). Visual acuity of 0.025 or better was obtained in 49 eyes (82%). Minimizing intraoperative complications as well as properly managing postoperative complications produced better surgical results.

Incomplete Central Retinal Artery Occlusion

Ophthalmic artery occlusion results in a circulatory disturbance of both central retinal artery and posterior ciliary arteries, causing an ischemia of retina and choroid. On fundus examination, white retinal opacification and cherry-red spot can be noted if central retinal artery occlusion is not associated with lateral posterior ciliary artery obstruction. If, however, central retinal artery occlusion is asssociated with lateral posterior ciliary artery obstruction, the cherry-red spot is no longer visible. The author experienced five patients with a mottled loss of retinal transparency in the macular region. Combined central retinal artery occlusion with obstruction of both medial posterior ciliary artery and lateral posterior ciliary artery were observed in two patients, both central retinal artery occlusion and medial posterior ciliary obstruction in two patients, and central retinal artery occlusion alone in one patient. The fundus findings in all five cases are compatible with an incomplete central retinal artery occlusion which in at least four cases was associated with evidence of choroidal vascular obstruction.

Surgical Results of Anterior Proliferative Vitreoretinopathy

Proliferative vitreoretinopathy is the principal cause of failure in rhegmatogenous retinal detachment surgery. The final cause of anatomic failure is anterior proliferative vitreoretinopathy. Surgical outcome of anterior proliferative vitreoretinopathy is poorer than that of posterior proliferative vitreoretinopathy. Of 147 cases which underwent vitreoretinal surgery from January through December 1993, 16 eyes(l6 patients) had anterior proliferative vitreoretinopathy. Seven eyes had anterior proliferative vitreoretinopathy at initial surgery(group 1). Remaining 9 eyes developed anterior proliferative vitreoretinopathy after primary vitrectomy(group 2). Of 16 eyes, 3 were aphakic, 2 were pseudophakic, and remaining 11 were phakic. Lens was removed in 11 phakic eyes. Meticulous vitreous base dissection and removal of anterior epiretinal membrane were performed. After minimal follow-up of 6 months, retina reattached in 11 eyes(69%) including all nine eyes of group 2. Nine eyes(56%) had postoperative visual acuity of 0.025 or better. These results suggest that both vitreous base dissection and meticulous removal of anterior and posterior epiretinal membrane should be crucial in improving surgical success rate of anterior proliferative vitreoretinopathy.

Spontaneous reattachment of retinal detachment with macular hole in nonmyopic patients

The occurrence of a retinal detachment in a patient with a macular hole is quite rare unless the patient is a high myope or has experienced ocular trauma. The incidence of spontaneous reattachment of retinal detachment with a macular hole is not uncommon in the highly myopic patients. However, data on nonmyopic cases are lacking. I herein describe two nonmyopic cases of retinal detachment with a macular hole, of which retinas reattached spontaneously.

Vitreous Surgery for Retinal Detachment associated with Acute Retinal Necrosis Syndrome

The acute retinal necrosis syndrome(ARN) is characterized by acute peripheral necrotizing retinitis, occlusive arteritis, and panuveitis. ARN is often complicated by late retinal detachment and a poor visual outcome. We describe herein a series of 4 consecutive patients(5 eyes) with ARN, complicated by retinal detachment. A patient with bilateral ARN(case 1) underwent prophylactic vitrectomy, 360 degrees scleral buckling, and intravitreal injection of acyclovir on the right eye while the retina was attached. Subsequently, the retina became detached. The retina was successfully reattached by performing fluid-gas exchange and laser photocoagulation. Argon laser photocoagulation was performed as a prophylaxis to prevent retinal detachment in two eyes. However, the two retinas subsequently detached. The two eyes were treated with vitrectomy, 360 degrees scleral buckling, fluid-gas exchange, and endolaser photocoagulation. Remaining two eyes required vitrectomy, silicone oil injection, and endolaser photocoagulation with(case 3) or without(case 4) 360 degrees scleral buckling. The retinas remined attached in all five eyes with no additional treatment. Four eyes achieved a visual acutiy of 0.1 or better. One had a final visual acuity of FC/40cm because of macular pucker and optic nerve atrophy.

Posterior Chamber Intraocular Lens Implantation Combined with Pars Plana Lensectomy and Intraocular Foreign Body Removal

Four patients with intraocular foreign bodies and traumatic cataracts underwent combined pars plana lensectomy, vitrectomy, and intraocular foreign body removal. During pars plana lensectomy, anterior lens capsule and zonules were left intact. At the end of surgery, a posterior chamber intraocular lens was placed in the sulcus in front of the anterior capsule through a 7-mm limbal incision. This procedure was performed in selected cases of combined anterior and posterior segment trauma. Combining pars plana lensectomy and posterior chamber intraocular lens implantation with posteior segment procedures allows rapid visual rehabilitation and functional unaided vision. We therefore suggest that this technique is effective in treating selected patients with both cataract and vitreoretinal diseases.

Causes of Failure after Initial Vitreoretinal Surgery

We reviewed the records of 23 patients who underwent repeat operation after initial vitreoretinal surgery in Chungnam National University Hospital between January 1993 and December 1993. Of 193 eyes who underwent vitreoretinal surgery in that period, 23(12%) had undergone reoperation. The most common cause of initial anatomic failure and reoperation was either new or recurrent proliferative vitreoretinopathy(10 eyes). Other causes included iatrogenic retinal tears(5 eyes), hidden retinal breaks(4 eyes), vitreous traction(1 eye), inappropriate chorioretinal adhesion(1 eye), and new break(1 eye). We performed vitreous base dissection on all 9 eyes with anterior proliferative vitreoretinopathy. With additional surgery and after a mean follow-up period of 10.4 months, 21(91%) of 23 retinas were reattached. The final cause of anatomic failure was anterior proliferative vitreoretinopathy. Of the 23 reoperated eyes, 20(87%) had postoperative visual acuity of 0.05 or better.

A Case of Cilioretinal Artery Occlusion Associated with Central Retinal Vein Occlusion

A cilioretinal artery occlusion associated with a central retinal vein occlusion is a rare condition and has been reported to have a good visual prognosis. We report a young patient with this condition who also demonstrated prolonged filling of the branch retinal arteries with fluorescein angiography. Her initial visual acuity was 0.03 in the affected eye. Two months later, normal central retinal artery inflow resumed. Her visual acuity has improved to 0.5 over the three years' follow-up.

Two cases of Multiple Evanescent White Dot Syndrome

Multiple evanscent white dot syndrom(MEWDS) has the characteristic clinical, funduscopic, fluorescein angiographic and electrophysiologic findings. The etiology of MEWDS remains unknown. The authors report on two patients with MEWDS. They were young females. Funduscopic examination showed that multiple, white dots are found at the level of the retinal pigment epithelium. These dots extended from macula into mideriphery. Also, the patients had a tiny, granular gray-white dots in the fovea. Fluorescein angiography showed an early hyperfluorescence in the areas corresponding to the white dots with late staining. Two patients had spontaneous recovery of vision in four to seven weeks. They had persistent enlargement of the physiologic blind spot or paracentral scotoma in their visual field, respectively.

Repetitive low-dose tissue plasminogen activator for the clearance of experimental vitreous hemorrhage

Our previous experimental work with tissue plasminogen activator (TPA) suggested the possibility of the clearance of vitreous hemorrhage by repetitive injections of low-dose TPA. We therefore investigated in rabbits the effect of both repeated injections of TPA and the change of the integrity of the vitreous body on the clearance of vitreous hemorrhage. Vitreous hemorrhage was produced by intravitreal injection of 0.05 ml of autologous whole blood in the pigmented rabbit eyes with intact vitreous or gas-compressed vitreous. Three intravitreal injections of 3-g TPA (total dose of 9 microgram), separated by 7-day intervals, were performed. The endpoint for vitreous hemorrhage clearance was defined as clear visualization of the posterior central retina of the rabbits. Regardless of whether gas compression vitrectomy was performed, repeated injections of low-dose TPA resulted in rapid clearance of fresh vitreous hemorrhage in approximately two to three weeks after the last TPA injection. No evidence of retinal toxicity was seen in all experimental groups. Repetitive injections of low-dose TPA may be effective in the treatment of fresh vitreous hemorrhage.

Posterior Chamber Intraocular Lens Implantation in front of the Anterior Lens Capsule during Pars Plana Lensectomy and Vitrectomy

Many patients present simultaneously with visually significant (to the patient and surgeon) lens opacities and vitreoretional disease. Traditional management of this problem has included two operations: vitrectomy followed by cataract extraction or cataract extraction followed by vitrectomy. Visual rehabilitation of aphakic eyes after pars plana vitrectomy is often difficult when anatomic objectives are achieved. Intraocular lens provides more natural and convenient vision. Now, simultaneous cataract extraction and lens implantation during pars plana vitrectomy can be considered. We performed posterior chamber lens insertion in the ciliary sulcus after completion of pars plana lensectomy, vitrectomy, and removal of intraocular foreign body. During pars plana lensectomy, we left the anterior lens capsule and zonules intact. After posterior chamber lens insertion, we removed the central anterior lens capsules from behind the optical component leaving a peripheral rim to support the haptics. The procedure provided good pseudophakic vision.

Treatment of Infectious Endophthalmitis

Endophthalmitis is a rare but catastrophic complication of intraocular surqeries and penetrating injuries. In spite of advances in diagnosis and therapy, the overall prognosis for recovery of useful vision has been regarded as poor. We experienced eight cases of endophthalmitis and performed vitrectomy combined with intravitreal antibiotics. Four(50%) had a final isual acuty of 0.2 or better. Vitrectomy was performed in cases of advanced intraocular inflammation, and intraocular lens was removed for suspected fungal endophthalmitis or to facilitate performance of a vitrectomy. A sample of vitreous, diluted by the irrigating solution, was passed through a disposable membrane filter system and inoculated into the culture media. Modification of therapy after initial broad spectrum antibiotics was based on the culture results and clinical responses. Repetitive intraocular antibiotic injections or reoperation were performed in severe cases.

Transecleral Suture Fixation for a Posterior Chamber Intraocular Lens Implantation

Posterior chamber intraocular lenses were implanted into 20 eyes without the posterior capsular capsular support by securing both haptics of the lens to the sclera with 10-0 prolene suture. The follow-up period ranged from 6 to 24 months(average 9.4 months). At the last follow-up visit, 17 eyes(85%) had a vision of 0.7 or better. The position of the implanted lens was proved satisfactory when compard with eyes with posterior chamber intraocular lens without scleral fixation suture by postoperative A-scan measurement of the anterior chamber depth, the results of refraction and slit-lamp examination. There were no eyes with remarkable decentration or tilt of the implanted lens. In two eyes, intraoperative bleeding occurred from the inferior chamber angle and ceased spontaneously. Postoperatively there were no remarkable inflammatory responses or complications. From the results, we suggest that the position of scleral puncture with a hypodermic needle is 1.2 - 1.4mm from the posterior surgical limbus in the upper quadrant and the advancement of the needle is directing parallel to the posterior surface of the iris.

Early surgical management in bilateral acute retinal necrosis

One patient with bilateral acute retinal necrosis underwent encircling scleral buckle, vitrectomy, and intravitreal acyclovir on both eyes. This procedure was performed on the right eye while the retina was attached. The retina of the right eye was reattached by performing fluid-gas exchange and modified panretinal photocoagulation when the retina subsequently detached. Soon after the development of retinal detachment in the left eye, the above surgical procedures were performed on the left eye, and the retina was successfully reattached.Bilateral acute retinal necrosis with significant vitreous opacification, which is a devastating ocular disease causing possible blindness in both eyes, requires more aggressive, early surgical management.

Resolution of experimental intravitreal fibrin by tissue plasminogen activator

Intravitreal fibrin clots were produced by intravitreal injection of 0.2 ml of autologous plasma in 62 rabbit eyes. The intravitreal injection of 0.25 micrograms or more of tissue plasminogen activator(tPA) resulted in a total clearing of intravitreal fibrin within one day in all treated eyes. This was significantly faster than in the control eyes, in which complete clearing was not seen until 8 days later. This represents the plateau on the dose-response curve in doses ranging from 0.25 to 200 micrograms. With light microscopy and transmission electron microscopy, retinal toxicity was demonstrated in eyes enucleated seven days after injection of 25 micrograms or more of tPA. This study demonstrates that tPA was effective and safe at 12.5 micrograms or less in clearing intravitreal fibrin in an experimental model. These results suggest that low dosages of tPA, probably of 3 micrograms or less, may be useful in the treatment of severe postvitrectomy fibrin formation seen clinically.

Treatment of experimental vitreous hemorrhage with tissue plasminogen activator

Tissue plasminogen activator(tPA) is a fibrin-specific fibrinolytic agent that has recently been shown to be effective in accelerating the clearance of hyphema. Intravitreal injection of tPA can promote rapid lysis of experimental intravitreal fibrin clots. The purpose of this study was to investigate the efficacy of intravitreal tPA injection for the treatment of vitreous hemorrhage in normal phakic non-vitrectomized rabbit eyes. Vitreous hemorrhages were produced by intravitreal injections of 0.05 ml of autologous whole blood in 25 rabbit eyes with intact vitreous. The injection of 25 or 100 micrograms of tPA in 15 eyes resulted in the clearance of vitreous hemorrhage in 99 +/- 19 or 34 +/- 6.5 days, respectively. This was significantly faster than in the control eyes in which the clearance was not seen until 131 +/- 17 days later. No tractional retinal detachment was observed.