Foveal Thickness between Stratus and Spectralis Optical Coherence Tomography in Retinal Diseases

PURPOSE: To compare the foveal thickness (FT) parameters measured by Stratus optical coherence tomography (OCT) and Spectralis OCT in various retinal diseases and to construct conversion formulas between the two types of OCT devices. METHODS: We examined 366 consecutive patients (475 eyes) with retinal diseases and 13 normal controls (13 eyes). The patients were categorized into eight retinal disease groups. The mean amount and distribution of foveal thickness differences (FTD) measured by Stratus and Spectralis OCT were determined, and conversion formulas were constructed for Stratus OCT FT from Spectralis OCT FT for each retinal disease group. RESULTS: Among retinal diseases, the mean FTD was significantly larger in exudative age-related macular degeneration (AMD) patients (mean +/- SD, 94.0 +/- 55.0 microm) compared to normal subjects (66.2 +/- 11.7 microm; p < 0.0001). The proportion of eyes with a mean FTD outside 1.96 standard deviations of normal subject FTD was greatest in the exudative AMD (50.0%) group and smallest in the macular hole (18.2%) group. The predicted FTs obtained through the conversion formulas showed lower variance than the actual FTD values, especially in the exudative AMD group. The prediction line for exudative AMD deviated most from that of normal subjects. CONCLUSIONS: FTD shows diverse values and variances among various retinal diseases, especially in exudative AMD, which indicates that Stratus OCT FT cannot be predicted from Spectralis OCT FT by FTD value alone. We constructed statistically significant conversion formulas, which provided more reliable methods to predict Stratus OCT-measured FT from Spectralis OCT measurements for different retinal disease groups.

Changes in Clinical Manifestations of Dry Eye Syndrome after Cataract Surgery and the Affecting Factors

PURPOSE: To evaluate the changes in the clinical signs and symptoms of dry eye syndrome before and after cataract surgery according to the main incision location and the type of artificial tears. METHODS: Twenty-four eyes of 17 patients who underwent phacoemulsification and posterior chamber lens insertion from May 2009 to July 2009 were enrolled in the present study prospectively. The main incision location (temporal or superior incision) was determined according to the axis of astigmatism and the postoperative artificial tears (sodium hyaluronate with or without preservatives) were determined randomly. The tear film break-up time (TF-BUT), Schirmer test, esthesiometer, corneal surface grading with Oxford system and ocular surface disease index (OSDI) questionnaire before and 1, 2 and 6 months after surgery were evaluated. The corneal nerve was also analyzed using corneal confocal microscopy (Confoscan 4, Nidek, Italy) before, and 1 and 6 months after surgery. RESULTS: The TF-BUT was significantly longer (p = 0.010) and the OSDI score was significantly lower (p = 0.007) in the patient group with preservative-free sodium hyaluronate than the group with sodium hyaluronate containing preservatives at 6 months after cataract surgery. There were no statistically significant differences according to the main incision location in the sodium hyaluronate without preservatives group. CONCLUSIONS: Symptoms and several signs of dry eye syndrome triggered by cataract surgery decreased with preservative- free artificial tears compared to tears with preservatives.

Acute-Onset Bilateral Myopia and Ciliochoroidal Effusion Induced by Hydrochlorothiazide

The authors experienced two cases of hydrochlorothiazide (HCTZ)-induced acute-onset bilateral myopia and shallowing of the anterior chambers. Two middle-aged women taking HCTZ, a sulfa derivative, visited our clinic complaining of acute bilateral visual deterioration. Both had good visual acuity without corrective lenses before taking HCTZ. A complete ophthalmologic examination revealed bilateral myopic shift, intraocular pressure elevation, shallowing of the anterior chambers, choroidal effusions, radiating retinal folds, and conjunctival chemosis. Approximately one week after HCTZ discontinuance, all ocular changes disappeared completely. Physicians should be aware of the adverse ocular effects of HCTZ and should manage patients accordingly.

Intraocular Lens Power Calculation Using IOLMaster and Various Formulas in Short Eyes

PURPOSE: To evaluate the predictability of intraocular lens (IOL) power calculations using the IOLMaster and four different IOL power calculation formulas (Haigis, Hoffer Q, SRK II, and SRK/T) for cataract surgery in eyes with a short axial length (AL). METHODS: The present study was a retrospective comparative analysis which included 25 eyes with an AL shorter than 22.0 mm that underwent uneventful phacoemulsification with IOL implantation from July 2007 to December 2008 at Seoul National University Boramae Hospital. Preoperative AL and keratometric power were measured by the IOLMaster, and power of the implanted IOL was determined using Haigis, Hoffer Q, SRK II, and SRK/T formulas. Postoperative refractive errors two months after surgery were measured using automatic refracto-keratometry (Nidek) and were compared with the predicted postoperative power. The mean absolute error (MAE) was defined as the average of the absolute value of the difference between actual and predicted spherical equivalences of postoperative refractive error. RESULTS: The MAE was smallest with the Haigis formula (0.37 +/- 0.26 diopter [D]), followed by those of SRK/T (0.53 +/- 0.25 D), SRK II (0.56 +/- 0.20 D), and Hoffer Q (0.62 +/- 0.16 D) in 25 eyes with an AL shorter than 22.0 mm. The proportion with an absolute error (AE) of less than 1 D was greatest in the Haigis formula (96%), followed by those in the SRK II (88%), SRK-T (84%), and Hoffer Q (80%). CONCLUSIONS: The MAE was less than 0.7 D and the proportion of AE less than 1 D was more than 80% in all formulas. The IOL power calculation using the Haigis formula showed the best results for postoperative power prediction in short eyes.

Comparison of the Detection Rate, Location and Amount of Retinal Nerve Fiber Layer Defect

PURPOSE: To compare the detection rate of the patients with retinal nerve fiber layer (RNFL) defect and the amount of RNFL defect according to the patients' age. METHODS: Retrospective chart reviews of 22,811 subjects, who visited the health care center from January 2009 to December 2009 were performed. The detection rate, location and average amount of RNFL defect and the proportions of the patients who were diagnosed with glaucoma through Humphrey visual field (HVF) test or determined as a glaucomatous optic disc were compared according to the patients' age. RESULTS: The proportions of the patients whose RNFL defect were detected was highest in the patients 60 years old or older (2.3%) and was statistically significant (p = 0.012). However, there was no significant difference among the other age groups (under 40 years: 1.7%, 40 thru 49 years: 1.5%, 50 thru 59 years: 2.0%). The proportions of the patients who were determined as glaucoma through the HVF test or glaucomatous optic disc were also highest in the patients 60 years old or older (1.4%), however, there was no statistically significant difference (p = 0.070) among the age groups (under 40 years: 1.1%, 40 thru 49 years: 0.9%, 50 thru 59 years: 1.2%). CONCLUSIONS: The RNFL defect is likely to be detected in subjects less than 40 years of age and the detection rate is similar to subjects in their 40's and 50's. The use of fundus photography to detect RNFL defect in a health care center is recommended in subjects under 40 years of age.

A Case of Coats' Disease Accompanying A Retinal Macrocyst

PURPOSE: To report a case of laser photocoagulation treatment for the patient of Coats' disease accompanying a retinal macrocyst. CASE SUMMARY: A three-year-old boy visited the hospital whose chief complaint was visual acuity decrease of his left eye. Fundus examination showed macular scar, foveal hard exudates and inferior retinal cystic lesion in his left eye. Two months later, examination under anesthesia (EUA) and fluorescein angiography (FAG) was performed. The results revealed inferior retinal macrocyst, nasal avascular retina and telangiectasia around the retinal macrocyst. Laser photocoagulation was performed around the retinal macrocyst and at the nasal avascular retina. One year after the laser photocoagulation, retinal macrocyst did not further progress and the retina was stabilized. CONCLUSIONS: Laser photocoagulation was done around the retinal macrocyst and at the nasal avascular retina of the Coats' disease accompanying a retinal macrocyst and the lesions did not further progress and the retina was stabilized.

The Study of Anatomical Attachment of the Extraocular Muscles following Recession with Hang-loose Technique in Rabbits

This study was designed to assess the postoperative status of the large-recessed superior rectus muscle using hang-loose technique(HLT) in rabbits. We also examined the histopathological featores of the muscles in HLT recession. The results were as follows: In HLT recession, anterior displacement of the muscles was noted in 16 of 20 eyes(80%) and the degree of anterior displacement increased in time to three months postoperatively. The average degree of displacement in 20 eyes was 1.1mm. The anterior margin of the muscle was parallel with limbus in 12 of 20 eyes(60%). In HLT recession, inflammation and foreign body reaction in the muscle decreased while fibrosis increased with time. Two weeks after HLT recession, adhesion between the muscle and the sclera was observed. Therefore, the authors thought that these findings should be considered in the clinical use of hang-loose technique.