Relationship between Preoperative Biometry and Intraocular Pressure Reduction after Phacoemulsification in Normal and Glaucoma Patients

PURPOSE: To investigate the relationships between preoperative factors and intraocular pressure (IOP) reduction after phacoemulsification in normal, open-angle glaucoma (OAG) and angle-closure glaucoma (ACG) patients. METHODS: IOP was measured before and 3 months after cataract surgery in 30 normal, 24 OAG and 31 ACG patients. The relationship between IOP reduction after cataract surgery and preoperative parameters including anterior chamber depth (ACD), axial length (AL), preoperative IOP/ACD ratio (PD ratio), preoperative IOP/AL ratio (PL ratio) were investigated in the 3 groups. RESULTS: Significant IOP reduction was observed in all 3 groups after surgery (paired sample t-test; p < 0.05), and IOP reduction was correlated with preoperative IOP level in all 3 groups (Pearson's correlation; p < 0.05). Other preoperative parameters such as ACD and AL were not correlated with IOP reduction, and PD ratio was significantly correlated with IOP reduction only in the OAG group (Pearson's correlation; p < 0.001). PL ratio was significantly correlated with IOP reduction in all 3 groups (Pearson's correlation; p < 0.05) and showed the best sensitivity and specificity to predict significant reduction in IOP after cataract surgery among parameters including preoperative IOP, PD ratio and PL ratio. CONCLUSIONS: PL ratio was significantly correlated with IOP reduction after cataract surgery in all 3 groups and showed a higher predictive value for IOP reduction in the OAG group than in the other groups.

Factor Influencing Anatomical Failure of Simple Rhegmatogenous Retinal Detachment

PURPOSE: This study analyzes the factors influencing anatomical failure of the primary operation for simple rhegmatogenous retinal detachment. METHODS: The patients in this study were diagnosed with simple rhegmatogenous retinal detachment and operated on by a single physician. The success group comprised 251 eyes and the failure group comprised 29 eyes. The factors analyzed between the two groups were the type of primary procedure, the type of retinal defect; the numbers of retinal defects; the extent of retinal detachment; the duration of retinal detachment; the existence of peripheral degeneration; carrying out of subretinal fluid drainage; the type of tamponade material used and the position of retinal defects. RESULTS: The anatomical success rate of the primary operation for simple rhegmatogenous retinal detachment was 89.64%. Patient sex, the type of tamponade material used and the position of the retinal defect showed significant differences between the success and failure groups. There was a higher percentage of male patients in the failure group than in success group (p=0.034). Silicone oil used as the tamponade material resulted in a greater chance of failure than success (p=0.017). Analysis of the position of the retinal defect showed that, defects distributed in the inferior retina or through multiple area led to a greater likelihood of anatomical failure (p=0.036). CONCLUSIONS: Due ti the greater possibility of anatomical failure of the primary operation when retinal defects are distributed in the inferior retina or through multiple area, clinicians should consider intensive treatment for such cases.

Effect of Correction Lens for Anisometropia on Aniseikonia and Binocular Function

PURPOSE: To study the effect of the corrective lens for anisometropia on aniseikonia and binocular function. METHODS: The study subjects were 30 patients without strabismus and amblyopia, who had anisometropia of more than 1.00D between the spherical equivalent of each correction lens. The amount of aniseikonia was measured by Awaya's New Aniseikonia Test. The degree of stereopsis and fusion were determined with Titmus Stereo Test and fusion card of major amblyoscope, respectively. RESULTS: The amount of aniseikonia increased significantly with increasing level of anisometropia (p=0.000). There was a statistically significant correlation between the amount of anisometropia and fusion (p=0.046). With increased aniseikonia, the stereopsis declined consequently, but the decline was not statistically significant. Aniseikonia was induced when there was more than 2.00D of anisometropia. With anisometropia increased by 1.00D, the odds ratio of induced aniseikonia was 7.197 (p=0.047). CONCLUSIONS: Anisometropia is an important factor for aniseikonia and can disturb binocular function.

Effect of Spherical Lens Induced Aniseikonia on Binocular Function

PURPOSE: To study the effect of spherical lens induced aniseikonia on stereopsis and fusion. METHODS: One hundred subjects, with normal binocular function without any ophthalmic disease or surgery history, were examined. The aniseikonia was induced with spherical lenses in 1 diopter (D) stepwise manner from -2 D to +2 D. The amount of aniseikonia was measured by Awaya's New Aniseikonia Test. Stereopsis and fusion were determined with Titmus Stereo Test and fusion card of major amblyoscope respectively. RESULTS: As the amount of aniseikonia was increased, the stereopsis and fusion were decreased. The change was statistically significant (ANOVA, p<0.001). Aniseikonia was more correlated to fusion than stereopsis. A significant decline in the stereopsis was detected when the size of aniseikonia changed from 1% to 2%. A significant decline in fusion was noticed when aniseikonia changed from 2% to 3% (Independent t-test, p<0.01). CONCLUSIONS: Our study suggests that binocular function can be disturbed by experimentally induced aniseikonia in normal subjects and that stereoacuities and fusional amplitude can be decreased as the degree of aniseikonia becomes larger.