长期配戴软性角膜接触镜者角膜上皮的病理改变

目的研究软性角膜接触镜对角膜上皮组织的基底细胞数目、上皮厚度、基底细胞形态、增殖细胞核抗原（PCNA）等的影响。方法前瞻性病例对照研究。选择配戴软性角膜接触镜超过3年的患者33例（66眼,角膜接触镜组）和从未配戴软性角膜接触镜患者33例（66眼,对照组）,对所选患者,在去瓣准分子激光上皮下角膜磨镶术（Flap—freeEpi．LASIK）手术中,用Epi-K角膜上皮刀取下角膜上皮瓣。2组中各取30例（60眼）采用超声进行离体角膜上皮瓣厚度的测量和采用显微镜进行基底细胞计数,各取3例（6眼）进行石蜡切片及免疫组化染色,观察角膜上皮瓣基底细胞形态的变化和进行PCNA的测定。数据采用独立样本t检验进行分析。结果角膜接触镜组角膜上皮层厚度为（55．33±4．56）μm;对照组角膜上皮层厚度为（57．19±3．82）μm,二者之间差异有统计学意义（t=-2．422,P〈0．05）。角膜接触镜组基底上皮细胞数目减少,为（3872．6±153．2）eells／mm^2;对照组基底上皮细胞数目为（3989．2±289．6）cells／mm^2,二者之间差异有统计学意义（t=-2．757,P〈0．01）。角膜接触镜组较对照组角膜基底细胞排列疏松,细胞形态欠规整,基底膜较厚,相对粗糙。角膜接触镜组角膜上皮基底细胞可发现PCNA阳性细胞,而对照组无阳性细胞。结论长期配戴软性角膜接触镜可导致角膜上皮损伤：使角膜上皮层变薄;单位面积内的的角膜上皮基底细胞数量减少;角膜上皮的组织结构发生病理学改变,细胞形态发生改变。细胞之间的连接和基底膜遭到破坏,PCNA阳性细胞存在。     

Histopathological analysis of the corneal epithelium after contact lens wear

Complications from contact lens wear are seldom examined histopathologically. Understanding of the epithelial reactions in response to contact lens wear would help early diagnosis and direct treatment action. Therefore, this study examines the histopathology of abrasion, epithelial edema, epithelial thinning and superficial punctate staining. Important factors in the etiology of these conditions are various definable lens and tear characteristics as well as mechanical effects from the lens. Observations on corneal innervation that have not been previously reported are used to help explain the reduced corneal sensitivity in the contact lens wearer. It is concluded that the breakdown of the epithelial surface prevents the epithelium from fulfilling its fluid and microorganism barrier functions. In addition, disturbance of the normal epithelial structure interferes with its ability to withstand further trauma and to convey the injury to the brain via the neural pathways.     

Proliferation rate of rabbit corneal epithelium during overnight rigid contact lens wear.

PURPOSE: To examine cell proliferation of the normal corneal epithelium and during extended rigid gas-permeable (RGP) lens wear. METHODS: Twenty-three New Zealand White rabbits were fitted unilaterally with either a low oxygen transmissible (Dk/t) or hyper-Dk/t RGP lens, with the other eye serving as a control. The rabbits were injected with 5-bromo-2-deoxyuridine (BrdU) 24-hours later and killed at three time points: 1, 3, and 7 days after injection. Corneas were processed for immunocytochemistry, and sequential digital images were taken from the superior limbus to the central epithelium with an epifluorescence microscope. The total number of BrdU-labeled cell pairs was quantified. RESULTS: The limbus in normal corneas was significantly less populated with BrdU-labeled cells than the central and peripheral epithelium (P < 0.05). The peripheral epithelium adjacent to the limbus was marked by a peak of labeled cells (P < 0.05). Both types of RGP lenses produced an increase in BrdU labeling in the limbus and a dramatic decrease in the central epithelium (80% for low Dk/t, 37% for hyper Dk/t). At day 3 and 7 after BrdU injection, the low-Dk/t lens continued to show decreased BrdU labeling centrally, whereas the limbus remained increased. Hyper-Dk/t lens wear however, showed persistent limbal elevation but equivalent numbers of BrdU-labeled cells centrally at days 3 and 7, compared with control corneas. Keratocytes unexpectedly showed BrdU labeling during RGP lens wear. CONCLUSIONS: Limbus, peripheral, and central epithelium were characterized by different proliferation rates in the normal rabbit cornea. RGP lens wear significantly altered the homeostatic proliferation pattern of the epithelium with the low-Dk/t lens having the most dramatic effect. RGP contact lens wear appears to stimulate proliferation of keratocytes.     

Extended contact lens wear enhances Pseudomonas aeruginosa adherence to human corneal epithelium.

Extended wear of soft contact lenses is associated with an increased risk of Pseudomonas aeruginosa infection of the cornea. To assess the role of bacterial adherence in the pathogenesis of these infections, superficial corneal epithelial cells and leukocytes from ten patients who use extended-wear soft lenses and ten control eyes were compared for their propensity to attach P. aeruginosa in vitro. Cells were washed from the cornea by saline irrigation, incubated with a 10-ml solution containing 10(7) colony-forming units/ml of bacteria at 35 degrees C for 30 min, collected on a filter, and prepared using a modified acridine orange staining method. Fluorescence microscopy showed bacterial adherence to corneal epithelial cells, leukocytes, and ocular mucus. The mean number of bacteria adhering to epithelial cells was 2.6 for control eyes and 6.6 for the lens-wearing eyes (P = 0.002). The percentage of epithelial cells attaching greater than or equal to four bacteria was higher for lens-wearing eyes than control eyes (57.4% versus 26.0%, P = 0.0005). There was no significant difference between contact lens-wearing eyes and control eyes in the number of leukocytes collected or in the number of bacteria attached to these cells. These results show that P. aeruginosa adherence to epithelial cells is enhanced in those who use extended-wear soft contact lenses, and this may contribute to the increased incidence of P. aeruginosa keratitis for this population.     

Spherical indentations of human and rabbit corneal epithelium following extended contact lens wear.

PURPOSE: Mucin balls appear to cause spherical indentations in the corneal epithelium during silicone hydrogel extended contact lens wear. The purpose of this report is to describe and quantify these spherical indentations, as examined in the human cornea by in vivo confocal microscopy and by in vitro immunocytochemistry in the rabbit cornea. METHODS: Confocal images of full-thickness corneal epithelium were taken from three human patients participating in a 1-year extended contact lens-wear trial. Diameter and depth of the indentations were determined and measured. Two rabbit corneas showing identical indentations were stained with propidium iodide (nuclear stain) and Ki-67 (proliferation marker) and were examined using a laser scanning confocal microscope. RESULTS: The diameter of the spherical indentations is largest on the epithelial surface, ranging from 33.9 to 78.8 microm. Indentations form spherical sections whose depth variably extends into the corneal epithelium, reaching as far as the basal lamina. The rabbit model showed no epithelial nuclei within the indentation. Furthermore, stromal cells localized immediately beneath the indentations were positive for Ki-67 (proliferation). DISCUSSION: Spherical indentations of the corneal epithelium induced by mucin balls appear to be gaps or holes that can extend deep into the corneal epithelium. Indentations may potentially open a pathway for infectious microorganisms to penetrate the cornea. Surprisingly, stromal cells immediately beneath the holes were stimulated to proliferate, and there seemed to be an increase in localized cell density.     

An extended wear hard contact lens in aphakia.

In reviewing the literature, there are several reports of limited success with both hard and soft contact lenses for continuous or extended wear. Aphakia is the most common indication for continuous wear, especially in monocular aphakes who are unable to insert and remove their lenses for various reasons. Because of its unusual oxygen permeability, silicone is the logical choice of material for an extended wear lens. However, because of the problems in manufacture, as well as its hydrophobic characteristics, poor centering, and problems with proper edging, no silicone lens has had wide clinical application to date. This paper reports on a preliminary study in a group of 21 aphakic patients fitted with the Polycon lens made of a new material consisting of polymethylmethacrylate in combination with silicone. Although gas permeable, the oxygen permeability is probably not adequate to maintain corneal metabolism without some interchange of oxygen containing tears. However, a significant proportion of the patients were able to wear this lens for an extended period of time without removal.     

软性角膜接触镜诱发角膜改变的共焦显微镜观察

目的应用共焦显微镜对长期配戴软性角膜接触镜所诱发的活体角膜组织改变情况进行观察.方法选择2002年8月～2003年4月于天津医科大学眼科中心门诊进行检查的患者36例(72眼),其中男性19例(36眼),女性17例(34眼),平均年龄为(27.63±10.7)岁,平均等效球镜度为(-5.87±0.67)D(-1.0～-9.0D),平均日戴时间超过8h,平均戴镜时间为(5.60±3.38)年(1～13年).选择未戴角膜接触镜者41例(82眼)作为对照组,其中男性20例(40眼),女性21例(42眼).平均年龄为(28.54±12.4)岁(18～52岁),平均等效球镜度为(-5.94±4.06)D(-1.25～-13D).结果戴软性角膜接触镜组角膜上皮的厚度为(42.6±6.1)μm,前基质角膜细胞密度为(1243±116)个/μm2,与对照组比较存在差异,其差异有显著性.戴角膜接触镜组的内皮细胞密度与对照组之间无差异,多形性内皮细胞和内皮细胞异形性百分比与对照组之间存在差异,其差异有显著性.结论长期戴软性角膜接触镜可诱发角膜组织改变.     

Blepharoptosis induced by prolonged hard contact lens wear.

PURPOSE: The authors attempt to establish a relation between hard contact lens wear and upper eyelid ptosis. METHODS: This study consists of two parts. In the first part, the authors compare the unilateral or bilateral ptosis that developed during hard contact lens wear in 17 patients with the involutional ptosis that developed in another group of 73 patients. In the second part, the authors compare both upper and lower eyelid position in 46 patients who had been wearing hard contact lenses for at least 10 years with the position of 50 matched controls who had never worn contact lenses. RESULTS: The ptosis that had developed in the 17 patients who wore hard contact lenses was clinically similar to that caused by involutional levator disinsertion. The second part of the study shows that the prolonged wearers of hard contact lenses had upper eyelids that were lower by approximately 0.5 mm when compared with control subjects. This difference is statistically significant. According to standard criteria, there were at least 10 ptotic eyelids in the contact lens group versus 1 in the control group. CONCLUSION: The study findings suggest that prolonged hard contact lens wear may induce a lower position of the upper eyelid and eventually lead to ptosis through levator disinsertion.     

The effect of hard contact lens wear on the keratoconic corneal endothelium after penetrating keratoplasty

Using wide-field specular microscopy, we evaluated the morphologic features of the corneal endothelium in 14 eyes of 14 patients with keratoconus who had worn a polymethylmethacrylate hard contact lens for at least four years (mean, 71 months) after penetrating keratoplasty. Comparisons were made with 14 non-lens-wearing eyes of 14 patients with keratoconus matched for age, length of postoperative period, and other variables. Examination of the endothelium of the contact lens wearers showed a significantly higher coefficient of variation in cell size (polymegethism) and a marked decrease in the percentage of hexagonal cells (pleomorphism), with a significant decrease in cell density (P less than .05). The cause of these morphologic abnormalities remains unclear but may be related to lens-induced hypoxic stress to the corneal endothelium causing ongoing cell loss.     

Morphologic effects of contact lens wear on the corneal surface.

We used specular microscopy of the corneal epithelium to examine 29 eyes of 29 patients each wearing one of five different types of contact lenses. We compared these with 24 eyes of 24 age-matched control patients. We found patients with aphakic extended wear soft contact lenses had significantly larger cells (818 +/- 186 microns2) than all other groups; and they were significantly larger than their age-matched control group (573 +/- 174 microns2) (P less than .002). The epithelial cells of extended wear soft contact lens patients (609 +/- 97 microns2) and daily wear rigid gas permeable contact lens patients (613 +/- 103 microns2) were larger than their control group of normal young patients (513 +/- 53 microns2). The cells of daily wear soft contact lens patients (484 +/- 111 microns2) and hard contact lens patients (517 +/- 46 microns2), however, were not different from controls. This study demonstrates a statistically significant shift in mean cell area of corneal epithelial cells in patients wearing some types of contact lenses.     

共焦显微镜评价长期配戴角膜接触镜对眼角膜组织的影响

目的应用共焦显微镜对长期配戴角膜接触镜患眼在不同时期的角膜组织的变化进行观察和分析。方法选择于大连医科大学附属一院眼科门诊进行检查的戴角膜接触镜患者47例（93眼1，年龄为17-38岁，屈光度为-1．75- 10．00D．平均日戴时间超过8h，戴镜时间为1～18年。分为三组：第一组（G1），戴镜时间5年以内者（含5年）；第二组（G2），戴镜时间5～10年者（含10年）；第三组（G3），戴镜时间10年以上者。另选择未戴角膜接触镜者15例（30眼）为第四组（G4），年龄为18～40岁，屈光度为-0．75～8．00D。共焦显微镜记录各层角膜图像,并对各层组织细胞形态、细胞密度等进行自动分析。四组间统计学分析采用单因素方差分析。结果①四组的角膜中央区Langerhans细胞密度分别为：（206．0±21．7）个/μm^2、（229．0±28．0）个／μm^2、（251．0±50．8）个／μm^2（154．0±36．7）个／μm^2。四组的角膜缘Langerhans细胞密度分别为：（308．0±76．4）个／μm^2、（364．0±53．9）个／μm^2．（417．0±83．6）个／μm^2、（254．0±127．0）个／μm^2。四组之间差异有统计学意义（P〈0．05）。②四组的角膜上皮厚度分别为：（51．2±4．5）μm、（45．6±2．7）μm、（43．5±5．0）μm、（53．6±2．5）μm。四组的前基质角膜细胞密度分别为：（1157．0±120．5）个／μm^2、（1094．0±103．0）个／μm^2、（1011．0±197．8）个／μm^2、（1187．0±139．0）个／μm^2。四组之间差异有统计学意义（P〈0．05）③四组的多形性内皮细胞百分比分别为：（36．2±1．7）％、（33．7±1．7）％、（32．8±1．5）％、（45．1±9．1）％四组的内皮细胞异形性百分比分别为：（56．5±3.4）％、（63．3±3．7）％、（64．2±7．11％、（45．8±12．2）％四组之间差异有统计学意义（P〈0．05）④四组的角膜全层厚度、后?     

Severe corneal infections associated with contact lens wear

An analysis of acute contact lens-related complications, with particular emphasis on severe microbial keratitis, was undertaken at the Department of Ophthalmology, Sahlgren's Hospital in Gothenburg. A total of 224 contact lens wearers presented with acute complications over a 2-year period (1981-1982). The lowest incidence of acute complications was found with hard contact lens wear. Similar numbers of daily wear and extended wear soft contact lens wearers presented with acute complications. The highest incidence of severe microbial keratitis was found in patients wearing soft contact lenses on an extended-wear basis. Inappropriate topical steroid therapy was implicated as a major factor contributing to the severity of these cases. Less severe sequelae of contact lens-related complications were also over-represented in the extended lens wear group. These findings emphasize the need for a conservative approach to the use of an extended wear regimen with soft contact lenses.     

Deep corneal stromal opacities in long-term contact lens wear

In 32 patients with long-term contact lens wear (up to 19 years), deep whitish opacities directly adjacent to Descemet's membrane were seen in the central part of the cornea. These opacities were seen in soft hydroxyethylmethacrylate (HEMA) as well as in hard (polymethylmethacrylate, PMMA) contact lens wear. These conditions could reduce visual acuity. When contact lens wear was discontinued or when the HEMA or PMMA lenses were replaced by gas-permeable rigid lenses, the lesions gradually diminished and resolved completely in most patients. One possible cause of these opacities is an allergic reaction to thimerosal. Another possible cause is chronic anoxia of the corneal stroma and endothelium. Endothelial cell density was not abnormal, but there was a marked polymegethism of the endothelium as a sign of endothelial stress.     

长期配戴软性角膜接触镜者角结膜上皮的变化

目的:探讨软性角膜接触镜(soft contact lens,SCL)长期配戴者角结膜上皮的变化。方法:正常对照组35例70眼,病例组99例198眼均采用角膜荧光素染色(fluorescein vital staining,FLS)、结膜印迹细胞学检查(conjunctival impression cytology,CIC)等检查方法。依据SCL戴镜时间将SCL戴镜者区分为<5a组,5~10a组和>10a组,共3组。比较分析各组间的角膜荧光素染色、杯状细胞密度和结膜上皮鳞状化分级的差异。结果:SCL戴镜各组FLS记分、杯状细胞密度与结膜上皮鳞状化分级与正常对照组间差异有统计学意义(P<0.01);<5a组与5~10a组间,及<5a组与>10a组之间杯状细胞密度与结膜上皮鳞状化分级的差异有统计学意义(P<0.01);但5~10a组与>10a组之间杯状细胞密度与结膜上皮鳞状化分级的差异无统计学意义。结膜上皮鳞状化分级与FLS呈正相关(r=0.589,P<0.01);杯状细胞密度与FLS负相关(r=-0.351,P<0.01)。结论:长期配戴SCL会引起角膜上皮损伤和结膜上皮印迹细胞学改变,且戴镜时间越长,损害越大。     

Not only hard contact lens wear but also soft contact lens wear may be associated with blepharoptosis

Objective

The authors attempt to establish an association between prolonged hard and soft contact lens wear and ptosis.

Design

Single-center retrospective consecutive series.

Participants

All patients between 18 and 50 years of age who were diagnosed with unilateral or bilateral ptosis between January 2002 and December 2005 (35 patients).

Methods

In a retrospective consecutive series, we included all patients between 18 and 50 years of age, with unilateral or bilateral ptosis between January 2002 and December 2005. Patients with congenital ptosis, ophthalmic surgery or disease, trauma, giant papillary conjunctivitis, unknown duration of contact lens wear, or muscular or neurologic disorders were excluded. We compared this study group to a Dutch reference population (the total underlying population from which the ptosis cases derive).

Results

The group included 35 patients: 20 (57%) (ages 18 to 50 years, average 37 years) had been wearing hard contact lenses for, on average, 17.6 years (range 6 to 27 years); 9 (26%) (ages 18 to 45 years, average 30 years) had been wearing soft contact lenses for, on average, 9 years (range 1.5 to 20 years); and 6 (17%) (ages 23 to 39 years, average 33 years) had no history of contact lens wear. The odds ratio for soft contact lenses was 14.7 (4.2 to 50.7; CI = 95) and for hard contact lenses 97.8 (22.5 to 424).

Conclusions

This study suggests that not only hard contact lens wear but also soft contact lens wear may be associated with ptosis.     

Long-term changes in corneal endothelial morphology after discontinuation of low gas-permeable contact lens wear

PURPOSE: Low gas-permeable contact lens wear of polymethyl methacrylate or hydroxyethyl methacrylate material is known to cause morphologic abnormalities in the corneal endothelial cell layer. These lenses were widely prescribed and successfully worn until their use was actively discouraged in the late 1980s and early 1990s. This study was designed to investigate whether discontinuation of low gas-permeable contact lens wear leads to an improvement of corneal endothelial cell morphology. METHODS: At the time of discontinuation and at least 5 years after discontinuation of low gas-permeable contact lens wear, noncontact specular photographs of the central corneal endothelium were made in 66 patients (14 male and 52 female, mean age 37.7 +/- 8.4, range 24.6-69.0). By computer analysis of endothelial photographs, parameters for polymegethism and pleomorphism were calculated, as well as cell density. RESULTS: Mean follow-up time between photographs was 6.8 years (SD 1.1). Sixty-one patients were refitted with rigid high gas-permeable contact lenses or high-water-content soft lenses, and 5 patients switched to spectacle wear. A small but significant recovery of the corneal endothelial cell morphology was found for the mean coefficient of variation of cell area, from 37.5 to 35.7 (P = 0.022), and for the coefficient of variation of the number of sides, from 13.1 to 12.4 (P = 0.004). The mean percentage of hexagonal cells increased from 54.2 to 56.2 (P = 0.013). Although the corneal endothelial cell morphology improved significantly on cessation of LGP contact lens wear, the values did not return to levels observed in normal, non-contact lens wearing individuals. During follow-up, the mean endothelial cell density decreased significantly (P = 0.001) from 2994 to 2890 (a 3.5% cell loss in 6.8 years), which is similar to the known normal age-related cell loss of 0.6% per year in non-contact lens wearing healthy individuals. CONCLUSION: Endothelial polymegethism and pleomorphism caused by PMMA or HEMA contact lens wear is partly reversible.