基于Pentacam HR的角膜屈光指数计算

目的 评估Pentacam HR测量角膜屈光术后眼角膜参数的可重复性并比较用Pentacam HR角膜参数计算未手术眼和角膜屈光术后眼角膜屈光指数的差异。设计 前瞻性研究。研究对象 接受角膜屈光手术术前及术后检查者,分为两组：A组为接受常规术前检查者207例207眼;B组为接受常规术前检查且术后3个月（LASIK）或6个月（PRK）以上复查者67例133眼。方法 A组受试眼行主觉验光和Pentacam HR检查;B组受试眼手术前后分别行主觉验光和Pentacam HR检查。两组中Pentacam HR检查均获得三次有效结果。主要指标  变异系数（CVw）、组内标准差（Sw）和组内相关系数（ICC）评估Pentacam HR获得的未手术眼（A组）和角膜屈光术后眼（B组）的角膜中央前表面3 mm范围内平均曲率半径（Ra）、角膜中央后表面3 mm范围内平均曲率半径（Rp）和中央角膜厚度（CCT）的可重复性。独立样本t检验分别分析A组和B组中计算获得的角膜屈光指数的差异。结果 A组中Pentacam HR获得的Ra、Rp和CCT分别为（7.780±0.235）mm、（6.341±0.225）mm和（541.67±31.79）μm; B组中Pentacam HR获得的Ra、Rp和CCT分别为（8.625±0.412）mm、（6.379±0.237）mm和（461.89±34.70）μm,均具有很好的可重复性（CVw均<1%,ICC均≥0.99）。基于Pentacam HR获得的参数计算角膜屈光指数,A组为（1.3278 ± 0.0008）;B组为（1.3227±0.0019）（t=34.634,P=0.000）。结论 Pentacam HR获得的未手术眼和角膜屈光术后眼角膜中央前、后表面3 mm范围内曲率半径和中央角膜厚度均具有很好的可重复性。基于Pentacam HR获得的角膜屈光术后眼的角膜屈光指数小于未手术眼的角膜屈光指数。（眼科, 2014, 23： 308-312）     

Color shifts induced by S-cone patterns are mediated by a neural representation driven by multiple cone types

This study investigated chromatic induction from inhomogeneous background patterns. Previous work showed that a background pattern detected by only S cones induced strong color shifts in a nearby test area (Monnier & Shevell, 2003). In that work, the S-cone patterns were composed with constant L- and M-cone stimulation over the entire background; in terms of L and M cones, therefore, the background was uniform. S-cone stimulation was varied over space to produce S-cone-isolated background patterns. These S-cone patterns, however, established spatial structure (the pattern) at both the receptoral level (S-cone stimulation) and the postreceptoral level (S/(L+M)). Here, these two levels of pattern representation were unconfounded to determine whether color shifts induced by S-cone patterns were due to spatial structure within an S-cone-specific neural pathway versus a pathway that combines responses from S cones and other cone types (e.g. S/(L+M)). The results showed that the induced color shifts were mediated by signals within a pathway that combines responses from multiple cone types. These results are consistent with a +s/-s spatially antagonistic neural receptive field, which is found in some neurons in V1 and V2.     

Evaluation of visual fields by ophthalmologists and by OCTOSMART program

The introduction of Goldmann perimetry standardized measuring conditions as much as possible. In spite of this, it had been possible for the perimetrist to influence the results of perimeter measurements. The introduction of computer-controlled perimetry, however, has largely eliminated the influence of the investigator on perimetry results. Nevertheless, the interpretation of a perimetric result in the everyday clinical situation is still extensively subjectively coloured and is liable to vary, depending on the doctor carrying it out. The OCTOPUS Program G1 was introduced a few years ago and used above all for glaucoma. This program greatly simplified visual field assessment thanks to its visual field indices. The indices make it possible to compare visual field results with those of a normal population. The present introduction of the OCTOSMART program represents a further step forward. This program analyses measured visual fields with the aid of standardized, statistical criteria based on a large, normal value study. This analysis standardizes and thereby simplifies the interpretation of visual field results. This study compares the outcome of the OCTOSMART program with visual field interpretations by eye doctors.     

Orbital decompression for Graves' ophthalmopathy by inferomedial, by inferomedial plus lateral, and by coronal approach

To test the efficacy and safety of orbital decompression for Graves' ophthalmopathy, the authors studied the records of 60 consecutive patients who were operated on for dysthyroid optic neuropathy or for rehabilitative purposes. Patients decompressed for neuropathy were older, had less proptosis, and a shorter duration of eye disease than patients operated on for disfigurement. The authors compared the results of three surgical procedures including the inferomedial, the inferomedial plus lateral, and the coronal approach. Regarding improvement of visual function, no difference was found between the three techniques. Patients in whom vision failed to recover had a high prevalence of diabetes mellitus. Proptosis reduction varied from 1 to 9 mm, depending on the number of walls decompressed. There was no net change in the prevalence of diplopia. Persistent complications were seen in less than 5% of all decompressions. The authors conclude that orbital decompression for Graves' ophthalmopathy is safe and efficacious, regardless of surgical procedure. However, the coronal approach gives the best cosmetic results.     

Filamentary keratopathy caused by corneal occlusion by large-angle paralytic strabismus

PURPOSE: To report a case of filamentary keratopathy in a patient with large-angle paralytic strabismus. METHODS: A 31-year-old man who had a traffic accident was diagnosed to have third cranial nerve palsy and a large-angle exotropia in his right eye. The patient complained of foreign body sensation in his right eye 2 months after the accident. RESULTS: Slit-lamp examination showed multiple filaments on the right cornea. Debridement of the filaments and artificial tears relieved the symptoms and were used until the paralysis resolved. CONCLUSION: Large-angle paralytic strabismus with ptosis and poor elevation and depression of the eye may occlude the cornea and lead to filamentary keratopathy.     

Acuity estimated by visually evoked potentials is affected by scaling

Seven subjects whose corrected Snellen acuities were normal had their monocular acuities (14 eyes) tested by visually evoked potentials (VEPs) elicited by eight checkerboard patterns which reversed 15 times per second. Check size ranged from 20 to 3.4 min arc. Monocular VEP acuities were determined by least squares regression with linear or logarithmic scales of amplitude and pattern size. Pattern size was measured as arc minutes (horizontal size) or fundamental spatial frequency of the checkerboard. The extrapolated VEP acuities were obtained by analyses of variance and post hoc tests. The presence of statistically significant differences in VEP acuity which result from varying combinations of stimulus and response scales indicates a need for caution in selecting scales for VEP estimates of visual acuity.     

Screening by optometrists

The optometrist is well placed to screen a large proportion of the population for a variety of conditions. Two examples of such screening, for vascular hypertension and learning underachievement, are discussed.     

Retinopexy by endodiathermocoagulation

Retinopexy was performed by endodiathermy coagulation around a retinal tear provoked during dissection of epiretinal membranes. The dissection was a complement to vitrectomy for Candida albicans endophthalmia. The choice of this technique was dependent on the absence of need for the laser, and allowed an internal buffering to be carried out by the use of silicone oil. Angiography showed depigmented areas confirming the presence of scar tissue as seen in experimental rabbit studies. The scar involved the whole thickness of the retina and choroid adjacent to the cauterized pigmented epithelium. This method is simple and possesses the advantage of being able to be used when the perioperative laser beam is unable to cross the transparent media of the eye.     

ROS ingestion by RPE cells is turned off by increased protein kinase C activity and by increased calcium

The activation of protein kinase C (PKC) by phorbol myristate acetate (PMA) rapidly inhibits the phagocytosis of rod outer segments (ROS) by cultured rat retinal pigment epithelial (RPE) cells. PMA, at a concentration between 3.3 and 10 nM, blocks ROS ingestion by 50%, but does not inhibit the binding of ROS. The Ca2+ ionophore, A23187, also inhibits ROS phagocytosis, with an IC50 of about 0.5-1.0 microM and interferes with the ability of RPE cells to bind ROS. The effects of both of these drugs are reversible after drug washout. When PMA and A23187 are applied to cells consecutively, the effects are additive. These results suggest either that PMA and A23187, act upon the same proteins in the pathway which controls ROS ingestion, or that A23187 affects phagocytosis at the ROS binding level, while PKC affects steps further along the ingestion path. The effect of this process is to shut down the ingestion of ROS, as is seen during the prolonged feeding of ROS to RPE cells in culture.     

Pain induced by phacoemulsification performed by residents using topical anesthesia.

BACKGROUND AND OBJECTIVE: To evaluate patient-reported pain induced by phacoemulsification performed by residents using topical anesthesia. PATIENTS AND METHODS: This prospective study comprised 81 eyes of 76 consecutive patients having phacoemulsification under topical anesthesia. Surgery was performed by an experienced surgeon (group 1; n=41 eyes) or by two residents (group 2; n=40 eyes). No sedation or intracameral anesthesia was used in either group. Eighty eyes had clear corneal phacoemulsification with foldable acrylic posterior chamber intraocular lens implantation. Patients were asked postoperatively to grade the pain they experienced during the procedure using a visual analog pain scale from 0 to 10. RESULTS: The median pain score for the overall pain was 1.59 +/- 1.43 (range: 0 to 6) in group 1 and 1.95 +/- 1.64 (range: 0 to 7) in group 2 (P = .291). The mean pain score for the maximum pain perceived was 2.39 +/- 1.86 (range: 0 to 7) in group 1 and 2.53 +/- 1.67 (range: 0 to 7) in group 2 (P = .734). There was no significant correlation between the duration of surgery and the overall pain score (r = 0.102, P = .365). CONCLUSION: Topical anesthesia had sufficient analgesic effects in selected patients undergoing phacoemulsification cataract surgery by resident surgeons. The pain felt during the operation was low and tolerable.     

莫索尼定对兔高眼压损伤后视网膜的保护作用

目的探讨咪唑啉受体激动剂莫索尼定(Moxonidine,Mox)对兔眼压的影响和对急性高眼压损伤后视网膜的保护作用。方法家兔24只(兔眼48只),随机分为A组和B组,各12只家兔(24眼)。A组家兔右眼为模型眼(12眼),左眼为正常对照眼(12眼)。B组家兔右眼为Mox模型眼(12眼),左眼为Mox对照眼(12眼)。模型眼和Mox模型眼制备急性高眼压模型。Mox模型眼和Mox对照眼2次·d滴Mox滴眼液。正常对照眼和Mox对照眼给药后每间隔2h测定眼压。制模后1d、3d、7d、15d,观察每眼fERGb波振幅和视网膜超氧化物歧化酶活性变化。结果用药后Mox对照眼与正常对照眼相比眼压明显降低,滴眼后2h下降了26.1%,2～6h降眼压幅度较大,降眼压作用持续8h。模型眼1d时fERGb波振幅明显降低,3d时最低,随后略有回升,15d回升至52.0%.Mox模型眼3d、7d、15dfERGb波振幅明显高于模型眼(P<0.05)。制模后模型眼SOD活性先降低,3d时最低,随后逐渐回升。Mox模型眼在1d、3d、7d、15dSOD活性均高于模型眼(P<0.05)。结论Mox具有良好的降眼压作用。Mox可减轻急性高眼压对兔视网膜缺血性损伤,促进视网膜功能的恢复。     

Synthesis of chondroitin sulfate by fibrotic vitreous induced by monocytes and lymphocytes

Vitreous fibrosis was induced in rabbit eyes by intravitreal injection of monocytes and lymphocytes. The fibrotic vitreous and normal vitreous removed from experimental animals were then incubated with [3H]-glucosamine at 37 degrees C for 24 hr. The newly synthesized 3H-labeled glycosaminoglycans (GAGs) were isolated by 4 M GuHCl extraction followed by pronase digestion. The 3H-labeled GAGs were then characterized by gel-filtration column chromatography and by specific enzymatic degradation, i.e. hyaluronidase, chondroitinase AC and/or chondroitinase ABC. The disaccahrides derived from chondroitinase ABC degradation were identified by thin-layer chromatography. Our results indicated that 91% of the total glycosaminoglycan synthesized by normal vitreous was hyaluronic acid. In contrast, in the fibrotic vitreous, the synthesis of hyaluronic acid was decreased to 30% whereas the synthesis of chondroitin sulfate increased to 47% of the total newly synthesized glycosaminoglycans. Control vitreous which was injected with freeze-thawed monocytes and lymphocytes synthesized 70% hyaluronic acid and 12% chondroitin sulfate although no fibrosis was observed.