A Study of Patients with Spasm of the Near Reflex

PURPOSE: To determine changes in the degree of pseudomyopia and convergence in patients with spasm of the near reflex. METHODS: In 5 patients with spasm of the near reflex, we checked following: UCVA/BCVA, the degree of pseudomyopia revealed through manifest and cycloplegic refraction tests, pupil size, limitation of EOM, the amount of convergence defined by the alternate prism cover test, and slit lamp and funduscopic exams. RESULTS: Of the 5 patients with spasm of near reflex, 3 had accommodative spasm alone and 2 had accommodative spasm, convergence spasm and miosis. The patients' degrees of pseudomyopia and convergence were -8.0D and 14PD on the average. which disappeared after an average of 10.8 months but recurred in 1 of the 3 patients with accommodative spasm. As for spasm of the near reflex, 1 patient showed improvement in convergence but worsening pseudomyopia during the follow-up period, and another patient showed recurrence. CONCLUSIONS: The most common clinical feature of spasm of the near reflex is accommodative spasm. Patients with accommodative spasm alone showed better prognosis among all patients with spasm of the near reflex in terms of recurrence and the disease course.

Minimal Requirement of Limbal Epithelium for Successful Limbal Cell Transplantation in Rabbit Corneas

PURPOSE: To investigate the minimal requirements of the limbal epithelium for successful limbal stem cell transplantation and the healing process. METHODS: Nine rabbits were divided into 4, 6, and 8 clock-hour transplantation groups. Limbal autografts from the healthy fellow eye were transplanted to the iatrogenic damaged eye. The amniotic membrane served as a stem cell niche. Experimental corneas were evaluated by slit lamp examination and immunohistochemistry. RESULTS: In the over 9 hours transplantation group, the healing process of the epithelium from the limbal stem cell was revealed and cornea-specific keratin k3, transcription factor p63, and connexin 43 were detected by immunohistochemistry. The normal corneal epithelium was regenerated after 60 days postoperatively in the fellow donor eye. CONCLUSIONS: Limbal cell transplantation of over 9 hours seems to be a safe and effective method in the treatment of severe ocular surface disorders. In addition, the donation of limbal epithelium for up to 8 hours did not affect the normal corneal regenerating capability.

Long-term Follow-up Results of Hyperopic Refractive Change

PURPOSE: To investigate the trend of refractive change in hyperopic patients according to increases in age. METHODS: Eighty-eight children who had hyperopia of more than +1.50 diopters (D) and could be followed up for at least 5 years were included in this study. We divided the patients into two groups according to the level of initial hyperopia and retrospectively analyzed hyperopic refractive changes over a 5-year period according to age at initial diagnosis, presence of esotropia, amblyopia, astigmatism and anisometropia. RESULTS: We gained the following formula about the aspect of hyperopic reduction in 88 patients over a period of 5 years: Diopter (D)=7.99-2.14 Ln (age). The presence of anisometropia and amblyopia did not affect hyperopic reduction. Hyperopic reduction amounts in the group with a hyperopic eye of more than +5D at initial diagnosis were greater than in the group with a hyperopic eye less than +5D, and greater in the group with an astigmatic eye of more than 1D. The presence of esotropia and the age at initial diagnosis did not affect hyperopic reduction. CONCLUSIONS: We show that emmetropization in hyperopic children occurs according to the following formula: Diopter (D)=7.99-2.14 Ln (age). Both the initial level of hyperopia and the concurrent presence of astigmatism affected hyperopic reduction. However, the presence of anisometropia, amblyopia, esotropia and the age at initial diagnosis did not significantly affect hyperopic reduction.

The Effect of Capsular Tension Ring on Posterior Capsular Opacity in Cataract Surgery

PURPOSE: To determine the efficacy of tension ring on posterior capsular opacity by comparing the incidence of capsular opacity with cases undergoing intraocular lens implantation alone. METHODS: In this study, we examined as many as 73 eyes which had undergone cataract surgery including CCC by the same surgeon from September 1998 to September 1999. In the tension ring group of 38 eyes, we inserted the tension ring prior to intraocular lens implantation, while in the silicon lens group of 35 eyes, we did not use the tension ring. RESULTS: We compared the difference in percentage of posterior capsular opacity (PCO) between the two groups at 1 year postoperatively. The tension ring group (group 1) were associated with less PCO (0%) than silicone (11.4%) lens group (p=0.048). The visual acuity were not significantly different between the two groups (p=0.964). CONCLUSIONS: The use of capsular tension ring is associated with significantly reduced degree of posterior capsular opacity and is thought to reduce lens epithelial cell migration onto the posterior capsule by mechanical apposition of the posterior capsule.

The Change of Tear Flim after laser Epithelial keratomileusis and laser in situ keratomileusis

PURPOSE: To compare the effects of laser epithelial keratomileusis(LASEK) and laser in situ keratomileusis(LASIK) on tear secretion and tear film stability. METHODS: Sixty two eyes went through photorefractive surgery including LASEK(26 eyes, 14 patients) or LASIK(36 eyes, 18 patients) by the same surgeon from January in 2000 to April in 2000. Tear secretion was measured with schirmer test and tear stability was measured with tear breakup time(BUT) preoperatively and 2 months after procedures. RESULTS: In the LASEK group, the preoperative mean values were BUT, 7.46 sec; Shirmer, 11.92 mm, and at postoperative 2 months, they were 6.62 sec and 9.31 mm, respectively. The difference was statistically insignificant(P=0.51, P=0.22). In the LASIK group, the preoperative mean values were BUT, 7.56 sec; Shirmer, 10.56 mm. At 2 months, they were 5.56 sec and 7 mm, respectively. The difference was statistically significant(P=0.02, P=0.02). CONCLUSIONS: Our result showed that tear secretion seemed to be significantly decreased after LASIK, but not after LASEK.

Macular Hemodynamics before and after Retinal Photocoagulation in Branch Retinal Vein Occlusion using Heidelberg Retina Flow meter(HRF )

To investigate the pathogenesis of macular edema in branch retinal vein occlusion(BRVO)and its attributing factors, we measured the macular circulation using HRF(Heidelberg Retina Flowmeter)before, 1 hour, 1 day, and 1 month after grid laser photocoagulation in 12 patients. After laser photocoagulation, the macula circulation significantly increased in 8 eyes(group 1), and remained unchanged in 4 eyes(group 2). Mean postoperative macular circulation of group 1 was blood volume 136.2%, blood flow 148.0%, and blood velocity 144.4%. And mean postoperative macular circulation of group 2 was blood volume 103.8%, blood flow 97.8%, and blood velocity 98.8%. The mean age of the patient was higher in group 1(group1:mean age 59.0, group 2:mean age 43.5, p=0.0008)and the interval between the onset of BRVO and photocoagulation was longer in group 1 than in group 2(group 1:12.4 months, group 2:4.3 months, p=0.0233). Our results suggest that retinal autoregulation may play an important role in the resolution of macular edema in BRVO after grid photocoagulation. Therefore the evaluation of retinal autoregulation using HRF is important in determining the treatment guide line and the prognosis of photocoagulation.

Refractive Change and Complications of Reverse-inserted Foldable Intraocular Lens

To evaluate the refractive consequences and complications of inadvertently implanting reverse-inserted foldable posterior chamber intraocular lenses (IOL)from May 1997 to December 1998, a total of 8 eyes (8 patients) were analyzed.One of these patients was male, seven were female and the mean age of patients was 70 years.The used IOLs were Chiroflex 32-C31SX (4 eyes), Corneal SP57T (2 eyes), and AcrySof MA60BM (2 eyes).The SRK-II formula was used to predict target spherical equivalent refractive error (SE).Actual postoperative SE were determined at 1 year after surgery and these results were compared with nonreversed control group (29 eyes). The target postoperative SE were subtracted from the actual postoperative SE to calculate diopter differences, between the actual SE and the target SE.The mean (+/-standard deviation)diopter difference in reversed IOL group was -0.95D +/-1.04D (ranged from -2.81D to 0.87D)more myopic than control group :-0.13D +/-0.98D (ranged from -3.23D to 1.47D), but the differ-ence (0.82D)was not statistically significant (p=0.07).The mean postoperative 1 year visual acuity in reversed IOL group was 0.74 +/-0.24, and in control group 0.76 +/-0.22;the difference (0.02)was not statistically significant (p=0.83).Posterior capsular opacity (PCO)developed in only 1 eye in reversed IOL group after 1 year postoperatively, and it occurred in 1 eye in the control group.No statistically significant difference was found in the incidence of PCO between the two groups (Chi-Square test, p>0.05).There-fore reversed IOL group is likely to produce a satisfactory refractive result and not to warrant the risks of repositioning the lens.

Excimer Laser Photore fractive KeratectomyPRKfor Low and Mode rate Myopia using VIXS STAR Excimer Laser System

Excimer laser photorefractive keratectomy[PRK]for low and moderate myopia[-2D~-6D]has been performed recently as a predictable and effective method for correcting myopia. We analyzed refractive change, postoperative visual acuity, and postoperative complications of 168 eyes[104patients]for 6 months and 33 eyes among them for 1 year after excimer PRK using VISX STAR excimer laser system from February 1997 to February 1998.Among the patients male were 8 patients, and female were 96patients.The myopic range was from-2.00 diopters[D]to -6.00D with astigmatism less than 3D.Uncorrected visual acuity of 4/5 or better was achieved in 91%postoperatively ;corrected visual acuity of 4/5 or better in 97%postoperatively.Eighty-eight eyes received spherical photorefractive keratectomy[PRK]to correct myopia ;80 eyes received photoastigmatic refractive keratectomy[PARK]to correct both myopia and astigmatism.In spherical PRK group the mean spherical equivalent was -4.67 +/-1.69D preopratively, 0.11 +/-0.93D 6 months after PRK, -0.31 +/-0.80D 1 year after PRK ;in photoastigmatic refractive keratectomy[PARK]group these figures were -4 .9 4 +/-1.42D, -0.37 +/-0.81D, -0.62 +/-0.78D, respectively.In the PARK group13.8%were undercorrected but in the spherical PRK group only 5.7% were undercorrected.So we report the ndercorrection rate of PARK group was relatively higher than that of spherical PRK group, but statisticallyinsignificant[Chi-Square test, p=0.075, but Relative Risk=2.65].We evaluated the surgically induced astigmatism by using both Jaffe and Clayman's vector-corrected methods.In the spherical PRK group the mean surgically induced astigmatism[SIA]was 0.83 +/-0.49D 6 months after PRK, 0.72 +/-0.47D 1 year after PRK ;in the PARK group these figures were 1.36 +/-0.71D, 1.29 +/-0.72D, respectively.The differences between the two groups were statistically significant[unpaired T-test.p=0.001].Astigmatism greater than 0.25D was reduced in 23.86%and induced in 55.68%of eyes that received spherical PRK and astigmatism greater than 0.25D was reduced in 80%and induced in 3.75%of eyes that received PARK.There were several complications including transient punctate keratopathies[6 eyes, 3.5%], undercorrection [-1D][16 eyes, 9.5%], and overcorrection[-1D][28 eyes, 16.67%].The decrease in the best corrected visual acuity in 10 eyes[5.9%] may be the result of a grade 2 or more corneal haze[15 eyes]and central island[2 eyes].