In Ki Park

New Clinical Grading Scales and Objective Measurement for Conjunctival Injection

PURPOSE To establish a new clinical grading scale and objective measurement method to evaluate conjunctival injection. METHODS Photographs of conjunctival injection with variable ocular diseases in 429 eyes were reviewed. Seventy-three images with concordance by three ophthalmologists were classified into a 4-step and 10-step subjective grading scale, and used as standard photographs. Each image was quantified in four ways: the relative magnitude of the redness component of each red-green-blue (RGB) pixel; two different algorithms based on the occupied area by blood vessels (K-means clustering with LAB color model and contrast-limited adaptive histogram equalization [CLAHE] algorithm); and the presence of blood vessel edges, based on the Canny edge-detection algorithm. Area under the receiver operating characteristic curves (AUCs) were calculated to summarize diagnostic accuracies of the four algorithms. RESULTS The RGB color model, K-means clustering with LAB color model, and CLAHE algorithm showed good correlation with the clinical 10-step grading scale (R = 0.741, 0.784, 0.919, respectively) and with the clinical 4-step grading scale (R = 0.645, 0.702, 0.838, respectively). The CLAHE method showed the largest AUC, best distinction power (P < 0.001, ANOVA, Bonferroni multiple comparison test), and high reproducibility (R = 0.996). CONCLUSIONS CLAHE algorithm showed the best correlation with the 10-step and 4-step subjective clinical grading scales together with high distinction power and reproducibility. CLAHE algorithm can be a useful for method for assessment of conjunctival injection.

Recurrent Occlusion of Laser Iridotomy Sites After Posterior Chamber Phakic IOL Implantation

We report a case of recurrent occlusion of laser iridotomy (LI) sites after a Visian ICL (Implantable contact lens version 4, Staar Surgical AG, Nidau, Switzerland) implantation. A 45-year-old woman had bilateral ICL implantation after placement of two peripheral LI sites in each eye to prevent pupillary block. At one month after the operation, severe narrowing or occlusion of four LI sites occurred. After this, although she received four additional LIs at postoperative months 1, 6, 9 and 10 in both eyes, the narrowing or occlusion recurred. Mild chronic anterior chamber inflammation was observed intermittently throughout the follow-up period. We performed clear lens extraction in both eyes (at postoperative month 11 in the left eye and month 26 in the right eye) due to recurrent occlusion of the LI sites and excess trabecular meshwork pigment deposition presumably caused by the four repeated LIs. Recurrent obstruction of LI sites can occur after ICL implantation. These problems were unresolvable despite four repeated laser iridotomies. The risks associated with anterior uveitis must be considered when planning an ICL implantation.

Objective assessment of corneal staining using digital image analysis.

PURPOSE To validate a new objective digital image analysis technique to evaluate corneal staining. METHODS One hundred photographs of corneal staining from various ocular surface diseases in 100 patients were quantified by a new strategy: a combination of the difference of Gaussians (DoG) edge detection for morphologic properties of corneal erosions and the red-green-blue (RGB) systems and hue-saturation-value (HSV) color model for detection of color. To enhance the image, we adopted a median filter, Otsu thresholding, and contrast-limited adaptive histogram equalization (CLAHE). To validate the diagnostic value of this new strategy, the same photographs were also graded by two independent clinicians using the Oxford scheme and the National Eye Institute/Industry (NEI)-recommended guidelines. The correlation between the average subjective grade and objective image analysis measurement was evaluated using the Pearsons correlation coefficient. RESULTS The new algorithm showed a strong correlation with the clinical grading scale in the Oxford scheme and the NEI-recommended guidelines (R = 0.850 and 0.903, P < 0.001, respectively). The repeatability of the objective measurement was excellent (R = 0.994). CONCLUSIONS The new algorithm showed excellent correlation with the traditional subjective clinical grading scales. It may be useful for objective assessment of corneal staining, independent of disease conditions.

Technique for autologous nasal mucosa transplantation in severe ocular surface disease

Purpose To describe the detailed surgical technique used for harvesting and transplantation of autologous nasal mucosa grafts for ocular surface reconstruction, to evaluate the clinical results and utility of autologous nasal mucosa grafts in ocular surface diseases. Methods Autologous nasal mucosa was harvested from either the middle or inferior turbinate. It was transplanted on 11 eyes with severe ocular surface diseases including 4 eyes with chemical burns, 2 eyes with thermal burns, 1 eye with Stevens-Johnson syndrome, 1 eye with erythema multiforme major, and 3 eyes with extensively recurred pterygiums. Clinical outcomes were assessed based on ocular manifestation, epithelization, and visual acuity. Results The mean follow-up period was 19.9 months (range 13–32 months). Nasal mucosal tissues were safely excised, and their mucosal harvest sites were completely healed in 2 weeks without postoperative complications. All nasal mucosa autograft survived successfully with rapid epithelization, well-developed horizontal vascularization, and abundant mucin secretion. Clinical success, intact ocular surface epithelium without epithelial erosion more than 4 weeks, was achieved in all eyes. There was no recurrence of significant ulceration, conjunctivalization, fibrovascularization, Symblepharon, or pterygium. Conclusions Goblet cell transplantation using autologous turbinate nasal mucosa presents a promising treatment method in patients with severe ocular surface disorders.

Comparison of Rates of Change Between Binocular and Monocular Visual Fields

PURPOSE To compare rates of change between binocular and monocular visual fields. METHODS The study included 1264 visual fields from 62 normal-tension glaucoma patients with a minimum of nine pairs of visual fields for at least 5 years of follow-up. Integrated binocular visual fields (BVFs) were calculated from the two monocular visual fields using a binocular summation. Linear regression of mean deviation (MD) values was used to evaluate the rates of change of the BVFs and monocular visual fields. For each patient, the eye with the worse MD value at baseline was defined as the worse MD eye. The eye with the faster rate of change of monocular visual fields was defined as the faster-changing eye. RESULTS The mean age of subjects was 61.8 years at baseline, the mean number of paired visual field tests was 10.2, and the mean follow-up was 8.1 years. The mean rate of change in the BVFs (-0.10 dB/y) was significantly slower than that of the faster-changing eyes (-0.34 dB/y) and faster than that of the slower-changing eyes (-0.06 dB/y; P < 0.001 for both comparisons). Forty-five eyes (64.5%) among the worse MD eyes at baseline were identified as faster-changing eyes at last follow-up, and having a worse MD value at baseline was a risk factor for being the faster-changing eye (P = 0.025). CONCLUSIONS The rate of change in BVFs was intermediate between the rates of the faster-changing and slower-changing eyes.

Topographic analysis of eyelid position using digital image processing software

To propose a novel analysis technique for objective quantification of topographic eyelid position with an algorithmatically calculated scheme and to determine its feasibility.

Long-term Reliability of Diurnal Intraocular Pressure Patterns in Healthy Asians

Purpose To determine the long-term repeatability of diurnal intraocular pressure (IOP) patterns in healthy Asian subjects without glaucoma. Methods Twenty-three eyes in 23 healthy Asian subjects without glaucoma underwent diurnal IOP measurements using Goldmann applanation tonometry every 2 hours from 9 AM to 11 PM during two visits that were 8 weeks apart. To validate repeatability between visits, we calculated intra-class correlation coefficients (ICCs) mean IOP, peak IOP, minimum IOP, and IOP fluctuation at each time point and expressed the results as the difference between peak IOP and minimum IOP or as the standard deviation of all diurnal IOP values in the diurnal IOP curve. Results IOP repeatability was excellent at all time points, with ICCs ranging from 0.812 to 0.946 (p < 0.001). The 9 AM IOP showed the best repeatability between visits (ICCs, 0.946). Repeatability of mean IOP, peak IOP, and minimum IOP was also excellent (ICCs ranging from 0.899 to 0.929). However, IOP fluctuations showed poor repeatability, with an ICC lower than 0.15. Conclusions Long-term repeatability of diurnal IOP patterns in healthy Asian subjects was excellent. These findings suggest that IOP measurements at standardized times of the day will be useful for assessing the effectiveness of glaucoma therapy.

Comparison of Objective and Subjective Changes Induced by Multiple-Pinhole Glasses and Single-Pinhole Glasses

Multiple-pinhole (MPH) glasses are currently sold in many countries with unproven advertisements; however, their objective and subjective effects have not been investigated. Therefore, to investigate the effects of MPH glasses excluding the single-pinhole (SPH) effect, we compared the visual functional changes, reading speed, and ocular discomfort after reading caused by MPH and SPH glasses. Healthy 36 participants with a mean age of 33.1 years underwent examinations of pupil size, visual acuity (VA), depth of focus (DOF), and near point accommodation (NPA); tests for visual field (VF), contrast sensitivity (CS), stereopsis, and reading speed; and a survey of ocular discomfort after reading. Both types of pinhole glasses enlarged pupil diameter and improved VA, DOF, and NPA. However, CS, stereopsis, and VF parameters deteriorated. In comparison with SPH glasses, MPH glasses induced smaller pupil dilation (5.3 and 5.9 mm, P < 0.001) and showed better VF parameters with preserved peripheral VF. However, no significant difference was observed for VA, DOF, NPA, stereopsis, and CS. Reading speed using pinhole glasses was significantly slower than baseline; SPH glasses showed the slowest reading speed. Both types of glasses caused significant ocular discomfort after reading compared with baseline, and symptoms were worst with MPH glasses. In conclusion, both types of pinhole glasses had positive effects due to the pinhole effect; however, they had negative effects on VF, CS, stereopsis, reading speed, and ocular discomfort. In spite of the increased luminance and preserved peripheral VF with MPHs, these glasses caused more severe ocular discomfort than SPH glasses. This clinical trial was registered at www.ClinicalTrials.gov (Identifier: NCT02572544).

A Congruous Superior Quadrantanopsia Following a Junctional Scotoma Induced by Asperogillosis

A 69-year old man presented to us with decreased vision in his right eye and a relative afferent pupillary defect. Under the presumption that he was suffering from retrobulbar optic neuritis or ischemic optic neuropathy, visual field tests were performed, revealing the presence of a junctional scotoma. Imaging studies revealed tumorous lesions extending from the sphenoid sinus at the right superior orbital fissure, with erosion of the right medial orbital wall and optic canal. Right optic nerve decompression was performed via an endoscopic sphenoidectomy, and histopathologic examination confirmed the presence of aspergillosis. The patient did not receive any postoperative antifungal treatment; however, his vision improved to 20 / 40, and his visual field developed a left congruous superior quadrantanopsia 18 months postoperatively. A junctional scotoma can be caused by aspergillosis, demonstrating the importance of examining the asymptomatic eye when a patient is experiencing a loss of vision in one eye. Furthermore, damage to the distal optic nerve adjacent to the proximal optic chiasm can induce unusual congruous superior quadrantanopsia.