The Clinical Aspect of Breaks Responsible for Retinal Derachment Associated with Lattice Degeneration

This study was undertaken to evaluate the retinal detachment related to lattice egeneration. We reviewed 54 eyes of 54 patients who had undergone retinal reattachment procedure from May 1992 to May 1995 at Yeungnam university hospital. Forty cases (74%) were due to atrophic holes in the lattice degeneration and 14 cases (26%) were due to tears at the lateral or posterior margin of lattice degeneration. Among 40 patients with atrophic hole, 25 patients (62.5%) were under 30-year-old and 26 patients (70.2%) were myopic over -3.0D. Among 14 patients with marginal tear, 9 patients (64.2%) were over 50-year-old and 8 patients had a refractive error of under -3.0D. Lattice degenerations were located most frequently in the temporal quadrants (46 cases, 85%). Retinal detachment related to lattice degeneration occurred in 30 eyes (56%) at superior retina, 20 eyes (37%) at inferior retina, 4 eyes (7%) at total retina, and had a much less serious prognosis in cases of atrophic hole compared with tear due to macula was less frequently involved in atrophic hole.

Clinical Result of Excimer Laser Photoastigmatic Refractive Keratectomy Using VISX 20/20 B VisionKeyTM with Version 4.01 Software

Photoastigmatic refractive keratectomy (PARK) using VISX 20/20 B excimer laser with version 4.01 software was performed in 205 consecutive eyes of compound myopic astigmatism to assess the efficacy, predictability, and safety of excimer laser treatment of compound myopic astigmatism between September 1994 and June 1996. The mean preoperative manifest spherical equivalent refraction was -6.95+/-2.52D (range -1.13 to -15D) and the mean preoperative manifest cylindrical refraction was -1.25+/-0.76D (range -0.5 to -4.50D). The patients were followed from 6 months to 1 year (mean 9.19 months). At 1 year, 82(75.2%) of all 109 eyes receiving PARK were within 1D of plano refraction, and 88(80.7%) of all 109 eyes achieved uncorrected visual acuity of 20/30 or better. Postoperative refractions were stable after 3 months without significant early overcorrection. Mean postoperative astigmatism was -0.29+/-0.40D at 6 months and -0.24+/-0.42D at 12 months. Overall improvement of astigmatism was 75% at 6 months and 82% at 12 months by vector analysis using Alpins` method. In conclusion, PARK using VISX 20/20 B VisionKeyTM excimer laser with version 4.01 software appears to be effective in the treatment of compound myopic astigmatism with a relatively high degree of accuracy and safety. The predictability and stability of the postoperative refraction during the first 12 months seem to be quite reliable.

Visual Outcome of Central Retinal Vein Occlusion

This study was performed to investigate the visual prognosis in ischemic and nonischemic central retinal vein occlusion(CRVO), to investigate the difference in clinical course of two types, and to identify prognostic factors for poor visual outcome. Fifty seven patients with CRVO were included. Eyes were classified into ischemic or nonischemic type by indirect ophthalmoscopy and fluorescein angiography. Among 58 eyes, 27 eyes(46.6%) were of the nonischemic CRVO and 31 eyes(53.4%) of the ischemic CRVO. Nonischemic CRVO was more common in patients under 45 years and had more benign clinical course than ischemic CRVO. Factors significantly related to visual outcome were initial visual acuity in ischemic CRVO(P<0.01) and the presence of systemic disease in nonischemic CRVO(P<0.01). Hypertension and diabetes were the most commonly associated systemic diseases. The leading causative factors for poor visual outcome were chronic macular edema and neovascular glaucoma in ishemic CRVO, and chronic macular edema in nonischemic CRVO.

Argon Laser Photocoagulation for Neovascularization in Retinal Vein Occlusion

We performed a retrospective study of 47 patients(47 eyes) with retinal vein occlusion who had treated with laser photocoagulation for neovascularization from January 1991 through January 1992. Only cases with a minimum of one year follow up were included in this study. The majority of patients were 50 year old(78.7%). Sixteen patients were male(34%) and thirty one patients were female(66%). The proportion of branch retinal vein occlusion and central retinal vein occlusion was 74.5%, 25.5%, respectively. New vessles elsewhere were developed in 36 eyes(76.6%), new vessles on the disc in 7 eyes(14.9%), and 4 eyes(8.5%) had both types of neovascularization. The percents of regression in neovascularization was 72.3% which ranged from 84% for under 10 disc diameter area of retinal ischemia to 64% for over 10 disc diameter area of retinal ischemia. Vitreous hemorrhage occured in 12 eyes(25.5%) within 1 year and especially when ischemic area was over 10 disc diameters and associated with systemic vascular diseases.

Ocular Fundus Findings in Children with Strabismus

The authors have examined 980 children with strabismus who were 6 years of age or under at the Eye Clinic of Yeungnam University Hospital. This study was conducted during the 4-year period between January 1990 and December 1994. The main objective of this study was to determine the incidence and clinical characteristics of fundus abnormality in children with strabismus. The total number of subjects in this study are 980 cases. Sixty subjects(6.1%) are found to have optic disc, chorioretinal and vitreous anomalies. Among them, 26 cases(43%) are diagnosed as having optic nervehypoplasia, in 7 cases (12%) coloboma, in 4 cases(7%) morning glory syndrome, in another 4 cases persistent hyperplastic primary vitreous, and in 3 cases retinoblastoma. In our study, 6.1% of the patients with strabismus are found to have disorders in optic disc and vitreoretina. These finding suggests that infants and young children with strabismus should have been examined to detect other related disorders of the eye.

Intravitreal Tissue Plasminogen Activator and Gas Injection in Submacular Hemorrhage

Tissue plasminogen activator(tPA) has been used as useful adjunct in the submacular hemorrhage due to age-related macular degeneration, which was injected and able to dissolve clotted blood. It was also known that intravitreal injection of tPA was effective as much as subretinal injection for lysis of blood. Recently, the rationale was introduced that residual dissolved subretinal blood with tPA was displaced from fovea away by intravitreal injection of an expanding gas. We have experienced the improvement of vision in an 83-year old woman with submacular hemorrhage, treated with intravitreal tPA and gas injection.

Spontaneous Resolution of Sub-Retinal Pigment Epithelial Hemorrhage

Sub-retinal pigment epithelial hemorrhage, located between sub-retinal pigment epithelial space and Bruchs membrane, develops from various etiology and usually is associated with subretinal hemorrhage. When sub retinal pigment epithelial hemorrhage occurs with choroidal neovascularization(CNV) within macular area, it generally has a poor visual prognosis. We report the case of a 54-years old man who initially had large sub-retinal pigment epithelial hemorrhage with presumed CNV. Without treatmetn, visual improvement with spontaneous resolution of hemorrhage occured.

Detection of Hepatitis B Virus DNA in Tear of the patients with Hepatitis Surface Antigen Positive in Serum by Polymerase Chain Reaction

In order to examine a possibility of hepatitis B virus(HBV) transmission via tears, detection of HBV DNA in tear was esamined using polymerase chain reaction (PCR) in 39 patients with HBsAg positive in serum. The detection of HBV DNA in tears was compared that in serums. The patients were divided into group I (n=21, serum HBsAg+HBeAg-) and group II (n=18, serum HBsAg+/HBeAg+). The total detection rates of HBV DNA in tears and serums were 76.9% and 92.3%, respectively. In detail, detection rates of HBV DNA in tears were 71.4% (group I) and 83.3% (group II) and those in serums were 85.7% (group I)and 100% (group II). There was no statisticlly significant difference in detection rate between group I and group II (p>0.05). However, mean values for serum aminotransferase activities in group II were higher than those in group I (p<0.05). The titer of HBsAg or HBeAg did not influence on the detection rate of HBV DNA. With these results, it was found that HBV DNA would be easily detected in tear of patients with HBV infection and HBV could be transmitted via ophthalmic instruments touched with ocular surface. Therefore, history taking concerning hepatitis B, screening test for hepatitis B, chemical or physical sterilization of ophthalmic instruments, and vaccination for workers in ophthalmologic department would be important in prophylactic aspects.

A Clinical Experience of Phototherapeutic Keratectomy for Reis-Bucklers' Dystrophy

Reis-Bucklers' dystrophy is an autosomal dominant disorder involving Bowman's membrane. It usually appears as a recurrent corneal erosion in early childhood and is characterized by an irregular, semi-opaque accumulation of fibrous connective tissue in the area of Bowman's membrane and symmetrical progressive opacity of superficial central cornea. Eventually, it causes visual disturbance due to re-ticulated gray-white corneal opacity and corneal surface irregularity. The ophthalmic surgeons have met difficulties in the management of Reis-Bucklers' corneal dystrophy because of poor long-term results following conventional penetrating and lamellar keratoplasties. We experienced a case of Reis-Bucklers' dystrophy in 25 years old man which was confirmed by clinical and pathological evidences and successfully treated by excimer laser phototherapeutic keratectomy(PTK) with VISX 20/20 B(R). In conclusion, we would suggest that PTK could be another modality of management in this anterior corneal disease when surgical intervention is required.

A Case of Unilateral Retinitis Pigmentosa

Retinitis pigmentosa has been recognized as a symmetrical, bilateral, hereditary, tapetoretinal degeneration with night blindness, visual field loss, and abnormal ERG. Unilateral retinitis pigmentosa is a rather rare disease. Pedraglia described first reported a case of suspected unilateral retinitis pigmentosa in 1865. Francois and Verriest proposed the following four criteria of the unilateral retinitis pigmentosa: the presence of functional changes ophthalmoscopically typical primary pigmentary degeneration in the affected eye, the absence of a tapetoretinal dystrophy in the fellow eye with normal ERG over five years and exclusion of the inflammatory cause in the affected eye. We report a case of unilateral retinitis pigmentosa in 29 year-old female who has been followed for over five years.

Prevalence of Central Islands in Corneal Topographic Analysis after Excimer Laser Photo refractive Keratectomy for Myopia

We analyzed the central islands in corneal topography after excimer laser photo refractive keratectomy(VISX Twenty/Twenty B(R) with VisionKey(TM) VISX, Inc. Santa Clara, CA, USA) to evaluate the prevalence of central island and the factors associated with their occurrence, prospectively. Corneal topographic analysis using Corneal Analysis System(EyeSys Technologies, Inc. Houston, TX, USA) was performed in 94 eyes of 77 patients at the postoperative 1-, 3- and 6-months after excimer laser PRK. Central islands were seen in 27%(25/92), 10%(8/79) and 8%(5/64) of patients at postoperative 1-, 3- and 6-months, respectively. There was statistically significant decrease in the occurrence of central island between postoperative 1 and 3 months follow-up groups(p0.05). We found that there was no demonstrable effect of central islands on the decrease of best spectacle corrected visual acuity at postoperative 1 month(p>0.05). Occurrence was statistically significantly decreased in the patients treated with the version 4.01 of central island removal software(1 month: p<0.01, 3 months: p<0.05). We suggest that the version 4.01 software of VISX 20/20B(R) was very effective to reduce the prevalence of central island after excimer laser PRK. In conclusion, if the software would be adjusted to increase the number of pulses centrally, this might reduce the prevalence of central island. New strategies and algorithms might be developed to reduce the prevalence of central islands.

Clinical Experience of Conjunctival Flaps for Persistent Ulcerative Keratitis

One hundred and fourteen patients(72 males and 42 females) who received a conjunctival flap for uncontrollable corneal ulcers with medical therapy between June 1983 and October 1994 were studied retrospectively. The range of the patients' ages were 7 to 81 years in which 60s' were popular and the patients were followed up for 15.2 months in average. Major underlying conditions of the patients were microbial infection(40%, 46 eyes) and trauma (25%, 29 eyes). The pathogenic organisms were identified by culture in 35 cases. Gram positive organisms of which staphylococcus species were the commonest were found in 23 cases, while Gram negative organisms of which pseudomonas species were the commonest were found in 11 cases. The location of the corneal ulceration was central(48.2%, 55 cases), paracentral(25.4%, 29 cases), total(19.3%, 22 cases) and marginal(7.0%, 8 cases) in order. The methods of operations were consisted of bipedicle bridge flap(82 cases), total conjuncti val flap(20 cases) and partial conjunctival flap(12 cases) in which 108 cases could be followed up and 96 cases(89%) were healed completely with one operation. As a postoperative complication retraction and displacement (12 cases), melting(10 cases), corneal perforation under the flap(5 cases) and corneal staphyloma (3 cases) etc. were found. Conclusively, the conjunctival flap can be a choice of the procedure for improving corneal wound healing for persistent corneal ulceration recalcitrant to medical therapy.

Evaluation of VEP in Optic Nerve Diseases and Amblyopia

We performed full field pattern reversal VEP using UTAS-E 2000, in 87 eyes of the 70 patients with amblyopia(14 eyes) and optic nerve diseases; optic neuritis(21 eyes), optic nerve atrophy(23 eyes), toxic optic neuropathy(15 eyes) and optic nerve injury(14 eyes) from December 1993 to July 1994. This study was carried out to evaluate the relationship of the visual acuity with P1 amplitude, P1 latency, and to compare the latency of P1, and P1-N2 amplitude to each disease group and the normal groups. There was no correlation between the visual acuity and P1 latency, but significant correlation between the visual acuity and P1 amplitude(p<0.01). In the P1 implicit time, optic neuritis, optic nerve atrophy and toxic optic neuropathy patients presented marked delay and amblyopia patients presented moderate delay, but there was no other significant difference in each disease group. Over 50% of each disease group except amblyopia presented P1 destruction. Therefore, the authers concluded that P1 amplitude might not be good parameter in diagnosis of the optic nerve disease because of its variability to the visual acuity, but P1 latency and P1 destruction could be good parameter.

Risk Factors and Clinical Course of Bilateral Branch Retinal Vein Occlusion

We did clinical analysis of 14 patients who had bilateral BRVO. The peak age distribution of the patients was between 60 and 69 years of age. In this 14 patients, there were 12 women and 2 men, and the most commonly associated systemic disease was hypertension(50%). In majority of patients, the interval of disease onset between two eyes was within two years. Complications developed, including maculopathy, retinal neovascularization, vitreous hemorrhage, glaucoma, and retinal detachment. Twenty one of 28 eyes(75%) had a final visual acuity of 0.4 or less. The larger the size of capillary nonperfusion was the higher was the incidence of neovasculgulation was an effective means of prevention of vitreous hemorrhage in BRVO with neovascularzation, and vitrectomy that was done in case of persistent vitreous hemorrhage improved final visual acuity. Our findings suggest that women with history of unilateral BRVO associated with hypertension in seventh, decade have high risk of occurrence in fellow eyes within two years.

Acute Phase Retinal Phototoxicity Induced by Blue Fluorescent Light / 영남의대학술지

Even though phototherapy is an effective means of treating hyperbilirubinemia, adequate binocular shields are essential to prevent light hazard of retina during phototherapy. The phototherapy to young albino rabbits was performed under various conditions; exposured for 12, 24, and 48 hours, continuity or intermittence of irradiation, and use of shields. Although there was no definite pathologic change in indirect ophthalmoscopic examination, severe damage was seen at electron microscopic level. In all experimental groups, swelling and edema of photoreceptor were seen. at right after phototherapy. Futhermore, more severe damage was seen in case of intermittent irradiated group and prolong exposed group. In mydriatic eyes, severity of damage was similiar to non mydi iatic eyes, but area of retinal damage was more extensive than non-mydriatic eves.. In control group which was protected by binocular shields during phototherapy, no significant abnormality was found.

A Case of Crystalline Retinopathy

A 41-year-old woman showed a bilateral chorioretinal dystrophy with retinal crystal deposits, geographic areas of atrophy of the retinal pigment epithelium, and choriocapillaris in the posterior pole. Crystals were observed in the sensory retina and on the retinal vessels. But the patient did not have corneal crystals. There was no visual symptom, however, the results of electrophysiologic tests were subnormal. To our knowledge, this is the first report of Bietti's crystalline retinopathy in Korea.

Clinical Evaluation of The Retinal Injuries following Perforating Ocular Traumas

We reviewed the records of 152 patients with retinal injuries following perforating ocular traumas who had visited at the Department of Ophthalmology, Yeungnam University Hospital from March 1983 to December 1993. Young men predominated, and the most common cause of injury was metallic particle(63.3%). The ocular perforation site was found in sclera(38.2%), cornea(36.2%) and corneosclera(25.6%). The associated disorders with retinal injuries revealed retinal tear alone in 45 eyes, retinal detachment in 46 eyes, marked vitreous hemorrhage in 66 eyes, and endophthalmitis in 15 eyes. The site and length of perforating ocular injuries, traumatic cataract, traumatic hyphema, intraocular foreign body and endophthalmitis did not affect visual prognosis significantly. Significant predictors of good visual outcome were good initial visual acuity, absence of vitreous hemorrhage or retinal detachment, and early vitrectomy.

Surgical Management of Scleral Necrosis

Scleral necrosis is a focal thinning of the sclera, and causes an exposure of underlying uveal tissue, endophthalmitis, and eyeball perforation. The authors experienced 16 cases of scleral necrosis after pterygium excision and performed combined lamellar scleral grafting and conjunctival flap for 13 cases, and simple conjunctival flap for 3 cases. After 12 months of follow-up period, all of the scleral grafts healed well except one case of graft melting. Six cases associated with endophthalmitis showed three lines of mean visual acuity improvement with Snellen chart after postoperative healing of inflammation. Postoperative complications included temporary corneal erosion(6 cases), conjunctival cyst formation(2 cases), scleral graft melting(1 case), and partial absorption of conjuctival flap(1 case).

Vitrectomy for Vitreous Hemorrhage Associated with Branch Retinal Vein Occlusion

Fifty-two eyes with vitreous hemorrhages caused by branch retinal vein occulusion underwent pars plana vitrectomy. The vIsion was improved postoperatively in 50 of 52 eyes(96.2%) and no change or worsened in 2 eyes. Regarding postoperative visual acuity 73% showed 0.1 or better, and 0.5 or better in 25%. The lens opacity, the most common surgical complication occured in 14 of 43 phakic eyes, and the incidence of later lens opacification increased as the follow-up lengthened. Other surgical complications were retinal tear in 2 eyes, recurrent vitreous hemorrhage in 3 eyes and secondary glaucoma in 2 eyes. Thirty-two eyes revealed postoperative visual acuity less than 0.3, in which 20 eyes showed maculopathy as the cause of poor visual outcome, and surgical complications in 16 eyes. The level of vision depends lagely upon the macular function.

Pars Plana Vitrectomy in Pars Planitis and Posterior Uveitis

This study was undertaken to evaluate the effectiveness of pars plana vitrectomy in pars planitis and posterior uveitis. We performed pars plana vitrectomies in consecutive series of 31 eyes with pars planitis and posterior uveitis that were complicated with vitreous opacities, epiretinal membrane formation, tractional retinal detachment and posterior subcapsular cataract. Postoperatively improvement of visual acuity, 2 lines or more in Snellen chart, was noted in 19 eyes(61.2%) with a mean follow-up of 21 months. The inflammatory cells were not visible in anterior chamber or anterior vitreous after 1 month thereafter. In three patients, however, the postoperative visual acuities were worSe due to preoperatively combined cystoid macular edema, macular pucker and tractional retinal detachment. We believe early pars plana vitrectomy before the formation of epiretinal membrane is an important factor in minimizing and postoperative complications.