Volume 54 · Issue 12 · 2018

This issue focuses on ocular surface diseases. The responsible editorial committee responsible for the planning, composition and review of this issue is Professor Zhang Mingchang.

An artificial cornea is a lamellar porcine corneal implant. Artificial corneas may be beneficial for the shortage of cornea donors and eye banks. It is necessary to grasp the indications of artificial corneal transplantation and pay attention to its perioperative treatment to reduce relapse and rejection, so as to achieve the best postoperative effect. (Chin J Ophthalmol, 2018, 54: 881-882)

In recent years, the shift from inpatient treatment to non-inpatient treatment has become a major change in the medical service model, and day surgery is the concentrated embodiment of this change. With the continuous development of medical technology, the transformation of medical payment methods, and the increase of medical demand caused by the aging of the population, day surgery has been popularized in many countries^[1]In the past 20 years, it has also been developed vigorously in China.

Pterygium is a common ocular surface disease in clinic, which mostly manifests as degeneration, hypertrophy and hyperplasia of subconjunctival tissue, and slowly invades the center of the cornea in a triangular shape. The prevalence of pterygium is reported to be geographically related, and the overall prevalence of pterygium in China is approximately 9.84%^[1], which is similar to the global overall prevalence (10.2%). Based on this calculation, as the world's most populous country, it is estimated that the total number of pterygium patients in China exceeds 100 million.

Thanks to the Chinese Journal of Ophthalmology for opening the academic controversy column, so that some hot issues in clinical work can be widely discussed through academic controversy articles.

To investigate the classification, possible risk factors, managements and clinical outcomes of suction loss in small incision lenticule extraction (SMILE).

In this nested case control study, subjects undergoing SMILE surgery between September 2013 and September 2017 were enrolled in the study. Eyes suffered from suction loss were included in the suction loss group, and eyes without intraoperative complications and operated at the same date were included in the control group. The refraction and visual outcomes were evaluated at preoperative and postoperative 1 day, 1 week, 1, 3 and 6 months. Independent t test and Pearson relation analysis were used for statistical analysis.

The study included 206 cases (344 eyes), of which 25 cases (27 eyes) were in suction loss group and 181 cases (317 eyes) were in control group. Suction loss occurred at: (1) scanning posterior surface of lenticule (5, 18.5%); (2) scanning lenticule side cut (1, 3.7%); (3) scanning anterior surface of lenticule (16, 59.3%);(4) scanning incision (5, 18.5%). The main reasons included: (1) abnormal eye movement (14, 51.9%); (2) extra fluid on corneal surface (13, 48.1%). There was significant difference in cap diameter between two groups (t=2.341, P<0.05). At postoperative 3 months, 3.7% (1 eyes) of eyes in cases lost one line; 2.6% (6 eyes) of eyes in controls lost one line. 92.6% (25 eyes) and 91.3% (209 eyes) of eyes had a UCVA of 0.10 LogMAR or better in cases and controls, respectively; 85.2% (31 eyes) and 93.4% (214 eyes) of eyes had a residual SE between±0.50D in cases and controls, respectively.

Suction lost during anterior surface of cornea was most common in SMILE surgery. Extra fluid in cornea surface, sudden eye movement of patient and larger corneal cap may result in suction loss. And it may slow the visual recovery, but appropriate and effective managements will be benefited to the final visual outcomes. (Chin J Ophthalmol, 2018, 54: 890-896)

To report the efficacy of fornix reconstruction with conjunctival inclusion cyst marsupialization in severe symblepharon.

Retrospective cases series study. Four patients (4 eyes) with Conjunctival Inclusion Cyst Marsupialization and severe Symblepharon during June 2016 to June 2018 at the PLA General Hospital were included. All of them were treated with Conjunctival Inclusion Cyst Marsupialization. The morphology, depth of the conjunctival sac and the degree of symblepharon before and after treatment were compared to observe the surgical results.

After operation, the conjunctival sacs were deepened, and the average depth was 4.75 mm. After follow-up, 2 cases of conjunctival sac were basically normal, and 2 cases of conjunctival sac became shallow, but still better than before surgery.

For the patients with large Conjunctival Inclusion Cyst and severe symblepharon, the Conjunctival Inclusion Cyst Marsupialization have many positive effects of deepening conjunctival sac, relieving symblepharon, increasing the degree of eye movement, improving appearance and relieving dry eyes. At the same time, this operation can avoid recurrence due to incomplete cystectomy. (Chin J Ophthalmol, 2018, 54: 897-901)

To study the effects of ultraviolet light combined with riboflavin treatment (corneal collagen-crosslinking, CXL) on infectious control and stromal reconstruction of bacterial keratitis.

Experimental Study. A Staphylococcus aureus rabbit keratitis model was established by injecting Staphylococcus aureus broth into the shallow stromal layer of the right eye cornea of New Zealand white rabbits. Forty-four rabbits that successfully established the model were randomly divided into four groups: corneal collagen cross-linking (CXL) group, antibiotic group, CXL+ antibiotic group and untreated group, with 11 rabbits in each group. Before the treatment and at 3, 7, 14 and 28 days after treatment, slit lamp corneal examination, AS-OCT and in vivo confocal microscopy (IVCM) were performed. Clinical efficacy of different treatments were evaluated at different time points. Parameters including conjunctival hyperemia, corneal ulcer, infiltration, edema, and neovascular. Histopathological examinations of corneal lesions were performed in order to detect the infiltration, inflammatory cells and repair in corneal tissue. Normal data were compared with paired t-test and non-normal data were compared with paired rank sum test before and after treatment. Kruskal-Wallis rank sum test was used to compare 4 groups of data and the generalized estimation equation is used to compare the repeated measurement data at each time point and the comparison between the groups of the treatment groups.

After treatment, different time points and specimens for pathological observation, we obtained the following results:Conjunctival hyperemia: in CXL and CXL+ antibiotic groups after treatment for 3 days from treatment before 3 (2, -4) and 3 (2, -3),The reduction was 2 (1, -3) and 2 (1, -2), the difference was statistically significant (Z=-3.91, -5.50; P<0.008); 14 days, the antibiotic group changed from 3 (3, -4) to 2 (1, -2) after treatment, the difference was statistically significant (Z=-5.11, P<0.008); the untreated group had no statistical significance before and after treatment. After 14 days of treatment, the area of corneal ulcer (0.08±0.11) cm², (0.07±0.05) cm² in CXL group and CXL+ antibiotic group was significantly lower than that before treatment (0.40±0.18) cm², (0.49±0.24) cm². The difference was statistically significant. Significance (Z=-3.29, -3.64; P<0.008); after 14 days of treatment, after 14 days of treatment, neovascularization in the CXL and CXL+ antibiotic groups began to resolve, 1 (1, -2) and 1 (0, -2) at 7 days of treatment. decreased to 1 (1, -1) and 0 (0, -1), the difference was statistically significant (Z=4.57, 3.80; P<0.012 5); The degree of corneal edema was significantly reduced in the CXL group and the CXL+ antibiotic group at 14 days after treatment, which was reduced from (650±154) μm and (785±255) μm before the treatment to (432±95) μm and (455±109) μm, the difference was statistically significant ( t=4.50, 4.92; P=0.00); The density of corneal stromal cells was also reduced from (446±257)/mm², (321±145)/mm² to (107±66)/mm², (114±94)/mm², the difference was statistically significant (t=4.15, 4.76; P<0.05). Histopathological observation under light microscope showed that most of the corneal ulcers healed in the CXL group and the CXL+ antibiotic group at 7 days of treatment. The epithelial cells were clearly visible and misaligned, and a small amount of neutrophils in the stromal layer. The upper epithelial layer was treated for 14 days. The cells are arranged neatly, the structure is clear, and the inflammatory cells are significantly reduced.

Ultraviolet light combined with riboflavin corneal collagen cross-linking has a certain therapeutic effect on rabbit bacterial keratitis infection control and ulcer repair, and can be used as an auxiliary treatment for antibiotics. (Chin J Ophthalmol, 2018, 54:902-910)

To investigate the differential expression of small leucine-rich proteoglycans at mRNA level in Lumican transgenic mouse cornea with Real-time Quantitative PCR Detecting System.

Experimental research. Ten Lumican transgenic mice (5 male and 5 female) were chosen as experimental group and 10 wild mice (5 male and 5 female) were chosen as control group. All the mice were killed and enucleated both eyes at eight weeks of age. Gene expression levels of Lumican, Decorin, Biglycan, Keratocan, Fibromodulin in the excised corneas were analyzed by real-time quantitative polymerase chain reaction (RT-Q-PCR) using Real-time Quantitative PCR Detecting System. Differential expression within each group were analysed by fold changes and independent t-test.

There were statistic different expression level of Lumican, Decorin, Biglycan and Keratocan mRNA between experimental and control group. The expression level of Lumican RNA was found to be 1.497-fold increased relative to the control (t=4.34, P<0.05) , while Decorin, Biglycan, Keratocan were 0.648-fold (t=-9.98, P<0.05) , 0.522-fold (t=-7.74,P<0.05), 0.323-fold (t=-95.94, P<0.05)decreased in transgenic mice. Fibromodulin mRNA up regulated 1.193-fold in transgenic mice without statistic difference (t=1.66, P>0.05).

Lumican gene mutation(cDNA 569T>C) results in abnormal SLRP expression in transgenic mouse cornea at mRNA level, which may indicate that this mutation changes the structure of Lumican and impairs the function of regulating SLRP expression. Also, Lumican gene mutation leads to amio acid exchanging(L199P), which may hinder Lumican from binding to collagens and result in abnormal expression of SLRP at mRNA level.(Chin J Ophthalmol, 2018, 54:911-917)

To report the clinical outcomes and safety profile of 27G⁺ transconjunctival sutureless vitrectomy (TSV) in eyes with posterior segment disease.

Prospective, interventional case series. Eyes undergoing 27G⁺ TSV for a vitreoretinal surgery indication were included from Dec 2015 to Mar 2016. Change in visual acuity and occurrence of intraoperative and postoperative complications with minimum follow-up of 6 weeks were recorded.

Eighty-three eyes met the inclusion criteria. Surgical indications included epiretinal membrane (n=27), proliferative diabetic retinopathy (n=17), full-thickness macular hole (n=11), rhegmatogenous retinal detachment with or without proliferative vitreoretinopathy (PVR) (n=8), vitreous hemorrhage(n=7), vitreous opacities (n=7), diabetic macular edema non-response to anti-VEGF agents(n=4), intraocular lens or cataract nucleus dropped into vitreous cavity (n=2). Mean follow-up was 19 weeks (range 6-34 weeks). Visual acuity improved in all cases. The cutter incarcerated with trocar in a vitreous hemorrhage case. There were no other intraoperative complications and no case required sutured at the conclusion of surgery. Postoperative complications included transient ocular hypertension in 2 eyes (2.4%) and transient hypotony in 1 eye (1.2%). No cases of postoperative endophthalmitis, sclerotomy related retinal tears, or choroidal detachments were encountered in the follow-up period.

The 27G⁺ TSV was effective and safe for varied surgical indications with low rates of intraoperative and postoperative complications. (Chin J Ophthalmol, 2018, 54:918-922)

To investigate whether exogenous CRX gene would be able to induce Müller cells-derived progenitors to differentiate into photoreceptors.

Experimental study. Müller cells-derived progenitors resulted from primary Müller cells isolated from KunMing mice(5-7 days old) and cultured in free-serum media. Markers of Müller cells(glutamine synthetase, GS and Vimentin) and stem cells (Nestin and Sox2) were analysed by immnocytochemical assays. The secondary passage progenitors were divided into three groups: (1)the control group; (2)the empty vector group was transfected with lentivirus GFP; (3)the treated group was transfected with lentivirus GFP-CRX. After differentiation for 7 days, 7 days after differentiation, the expression of markers of photoreceptors were analyzed by q-PCR and Western blot assay.

There were 96.03%±1.21% of Müllerz cells cultured in vitro were immunoreactive to both GS and Vimentin. The dedifferentiation cells expressed Nestin and Sox2. After 7 days of induction, Exogenous CRX induced Müller cell-derived progenitors to differentiate into rod-like cells showed appearance like neuron morphology. q-PCR demonstrated that mRNAs of CRX and Rhodopsin were upregulated greatly. CRX mRNA were 9 times (P<0.05) and Rhodopsin mRNA were 20 times (P<0.05). The difference between the control group and the empty vector group was not statistically significant. Western blot showed that the expression of CRX was upregulated significantly, and was 2.7 times(P<0.05). But expression of Rhodopsin was weak and was nearly not detected in the control group and empty vector group. The expression of S-opsin was not detected.

CRX gene could induce the differentiation of Müller cell-derived progenitor into rod photoreceptors, indicating a new avenue to study müller cells as endogenous seed cells for retinal photoreceptor. (Chin J Ophthalmol, 2018, 54: 923-928)

To master the status of ophthalmic human resource allocation and service delivery at county level in Mainland China, and to provide the basis for strengthening the construction of grassroots ophthalmic personnel team and formulating feasible medium and long-term eye health plans.

All the medical institutions that provided ophthalmic service at county level or above were investigated by online reporting. This study only included medical institutions at county level. Descriptive statistics were used.

Three thousand three hundred and fifty-nine medical institutions were included, of which 1 463 hospitals had independent departments of ophthalmology (43.55%). Each medical institution has 3.93 ophthalmologists, 4.59 ophthalmic nurses, 0.30 full-time optometrist and 0.21 full-time optician. Ophthalmologists are mainly undergraduate, and the ratio of senior, intermediate and junior titles is 1.0∶1.7∶1.9. The ophthalmic nurses are mainly graduated from junior colleges or secondary schools, and the ratio of senior, intermediate and junior titles is 1.0∶7.3∶22.3. There were statistically differences in the distribution of job titles of ophthalmologists (χ²=106.21, P<0.01) and nurses (χ²=128.54, P<0.01) in the eastern, central and western regions. Of each ophthalmologist, the annual number of outpatient, outpatient surgery, inpatient and inpatient operation was 2 377.62, 109.79, 124.03, and 85.97 respectively. Four thousand one hundred and sixty ophthalmologists were able to carry out cataract surgeries independently, accounting for 31.50% of all ophthalmologists. The quantity for annual per capita cataract operation among ophthalmologists who can perform cataract surgery independently was 181.81 per capita. The average beds rate of utilization was 68.91%, and that was less than 60% in 52.99% of medical institutions.

Compared with 1998, ophthalmic health personnel at county level in Mainland China has expanded rapidly. But cataract ability of ophthalmologists and the number of cataract surgeries still need to be improved. The structure of ophthalmic nursing staff is irrational. The full-time optometrists and opticians are extremely scarce. It is necessary to cultivate high-quality ophthalmic health personnel and improve beds rate of utilization at county level. (Chin J Ophthalmol, 2018, 54:929-934)

患者男性，26岁，双眼近视眼。2017年4月于外院行双眼飞秒激光小切口角膜基质透镜取出术（femtosecond laser small incision lenticule extraction，SMILE）。术前右眼-6.25 DS（）-0.75 DC× 85°矫正至1.2左眼-6.25 DS（）-0.50 DC×85°矫正至1.2，角膜地形图未见异常。角膜中央厚度右眼为501 µm，左眼为503 µm；眼压、眼底均未见异常。SMILE术中透镜直径6.3 mm，切口长度2 mm，切口位置120^o，透镜厚度右眼106 µm，左眼103 µm。手术结束时发现左眼角膜中央上皮约2 mm糜烂。术后1 d上午复查双眼结膜轻度充血，角膜无明显异常，双眼视力1.0。术后给予0.3%左旋氧氟沙星、0.1%氟米龙、0.3%玻璃酸钠滴眼液滴眼4次/d。当日下午患者感觉左眼磨，不适，未处理。术后2 d左眼症状加重，感觉视物模糊，可见大量黄色分泌物，角膜中央原上皮缺损部位有黄白色浸润，考虑感染性角膜炎，停用0.1%氟米龙滴眼液，给予0.3%左旋氧氟沙星滴眼液每30 min 1次。术后第3天左眼症状加重，视力降至0.1，转入河南省眼科研究所。检查可见左眼睫毛根部大量黄白色分泌物，结膜混合充血，角膜水肿，角膜中央约直径1.5 mm的角膜帽融解，中央及颞侧各有一白色致密浸润灶，角膜层间大量炎症细胞浸润，角膜后壁少量颗粒状沉着物（图1），前房闪光（-）。眼前节OCT示角膜水肿，中央变薄，部分缺损，角膜层间混浊，角膜中央后表面前突（图2）。角膜地形图显示角膜前表面扁平，不规则，角膜帽融解处后表面前突，后表面高度达64 µm（图3）。取结膜囊分泌物及角膜刮片镜检及培养。角膜刮片镜检见大量坏死组织及少量革兰阳性球菌（图4）。诊断：左眼SMILE术后感染性角膜炎。加用头孢唑啉钠滴眼液1次/h，他克莫司滴眼液2次/d，加替沙星凝胶1次/d。全身静脉滴注头孢唑啉钠和维生素C。治疗3 d后症状减轻，视力恢复至0.2，裂隙灯检查可见角膜水肿减轻，中央上皮覆盖，浸润灶缩小，角膜层间炎症细胞减少，角膜后沉积物减少（图5）。细菌培养结果为表皮葡萄球菌（图6），对左氧氟沙星、莫西沙星、阿米卡星、阿奇霉素、头孢唑啉等药物敏感。停止全身用药，局部0.3%左氧氟沙星滴眼液，0.5%头孢唑啉滴眼液每2 h 1次，加点复方妥布霉素滴眼液4次/d。他克莫司滴眼液2次/d，加替沙星眼用凝胶睡前1次。继续治疗3 d症状明显减轻，视力恢复至0.4，裂隙灯检查见结膜充血减轻，角膜水肿、层间反应减轻，角膜透明性增加，角膜后沉积物消失，角膜上皮愈合，眼前节OCT显示角膜水肿消失，中央基质轻度混浊，角膜后表面前突后移（图7）。抗生素滴眼液减为4次/d。继续治疗1周，停用复方妥布霉素滴眼液，改为0.1%氟米龙滴眼液4次/d，他克莫司滴眼液2次/d，0.3%左氧氟沙星滴眼液4次/d。术后1个月复查，左眼裸眼视力0.8。裂隙灯检查角膜透明，瞳孔偏颞上方约2 mm大小薄翳。角膜地形图相应部位变平，原突起的后表面恢复正常，后表面高度变为10 µm（图8）。停用药物，观察3个月，视力稳定，角膜遗留薄翳（图9），角膜地形图无变化。

A 23-year-old male patient with blurred vision for 4 d 1 month after keratoconus surgery in his left eye was seen in Henan Provincial Eye Hospital on March 24, 2015. The patient was given tobramycin dexamethasone eye drops, gatifloxacin gel, sodium hyaluronate eye drops and bovine alkaline recombinant fibrous growth factor gel for 1 month after keratoconus surgery. The patient felt eye astringency and discomfort to see a doctor. In addition to the above drugs, vitamin A sodium palmitate eye drops were added for 1 week. Under the slit lamp microscope, the patient's left eye was wearing contact lenses, the conjunctiva was moderately mixed congested, the corneal graft and the implant bed were well aligned, the sutures were in place and clear, and 5 mm ×3mm irregular gray-white infiltration focuses were seen above the graft, epithelial defects, and the underlying matrix was turbid. The ulcer and turbid area was about 6 mm ×8 mm (Figure 1）。 Confocal microscopy of the cornea revealed a large number of fungal hyphae, vertically branched (Figure 2）； Following local anesthesia with 0.5% tetracaine, Giemsa staining microscopy of the corneal scraper revealed a large number of blue fungal hyphae with long, right or acute branches, and rod-shaped conidia (Figure 3）； No typical bacteria were seen. The corneal scraper and contact lens were inoculated in Sabourand medium, blood plate medium and enriched broth medium, respectively, and placed at 26℃ ~28℃ and 35℃ for fungal and bacterial culture. Patients were given alternating eye points with 0.5% natamycin eye drops, 0.5% voriconazole eye drops and 0.5% terbinafine eye drops once/h.

Case 1 was a 46-year-old female. On July 5, 2016, he went to the Department of Ophthalmology of Enshi Central Hospital because he was found to have no vision in his left eye for 2 months. Two months ago, the patient accidentally occluded his right eye and found that his left eye was not visible, without symptoms such as eye pain and eye swelling, without headache, convulsions, and without movement and sensory impairment. There was no diagnosis and treatment, and there was no obvious change in visual acuity after 2 months of self-observation. Past physical fitness. Ocular examination: visual acuity of right eye 0.8, anterior segment (-), unclear boundary of fundus optic disc, pale color, atrophic focus visible above temporal optic disc, unclear reflection of fovea, intraocular pressure 9.1mmHg (1 mmHg =0.133 kPa); The visual acuity of the left eye was 40 cm, without correction, anterior segment (-), fundus optic disc congestion, edema, unclear boundary, macular hemorrhage with yellow exudation, no foveal reflection, intraocular pressure 10.8 mmHg (Figure 1）。 Diagnosis: optic disc edema in both eyes. Routine systemic examination after admission excluded systemic diseases and infectious diseases. Specialist examination: OCT examination results showed thickening of nerve fiber layers on the nasal side and lower side of the optic disc of the right eye, and thickening of nerve fiber layers on the nasal side, temporal side and lower side of the left eye; Macular edema in the right eye was not obvious; The macular retina of the left eye was thickened and bulged, with multiple liquid dark areas between the layers (Figure 2，Figure 3）。 The results of FFA examination showed late fluorescein leakage and blurred boundary in the optic disk of both eyes; The temporal side of the optic disc of the right eye showed flaky hyperfluorescence with clear boundaries and no obvious enlargement in the late stage. Irregular flaky hyperfluorescence in the macular area of the left eye mixed with masked fluorescence, late leakage (Figure 4，Figure 5）。 CT examination showed that the left frontal lobe density was not uniform, and further MRI examination was recommended. MRI results showed abnormal signals in the left frontal lobe. Considering the possibility of vascular malformation, CT angiography is recommended (Figure 6）。 He was transferred to the neurosurgery department on July 10, 2016, and underwent digital subtraction angiography of the head on July 15, 2016. The results showed that the M2 segment of the left middle cerebral artery showed local vascular thickening and tortuous deformity, forming a vascular mass, arteriovenous communication, drainage vein flowing back into the superior sagittal sinus, left anterior cerebral artery atrophy and thinning, and left ophthalmic artery showed poor display; The right internal carotid artery supplies bilateral anterior cerebral arteries and some branches of the left middle cerebral artery, and a thickened and tortuous vascular mass similar to the M2 segment of the middle cerebral artery can be seen, with arteriovenous communication. No significant abnormalities were observed in the right ophthalmic artery (Figure 7）。 Resection of left frontal vascular malformation under general anesthesia on 16 Jul 2016. The visual acuity of the left eye recovered to 0.1 3 months after surgery.

The patient was a 25-year-old female. Due to the discovery of a subconjunctival mass in his left eye for 22 months and the enlargement of the mass for 3 months, he went to Beijing Tongren Hospital affiliated to Capital Medical University on December 8, 2016. The patient had no ocular and systemic symptoms and was previously in good health. Physical examination: There were no obvious positive signs on general physical examination. Ophthalmic examination: visual acuity 0.9 in the right eye and 1.0 in the left eye; IOP was 12 mmHg (1 mmHg =0.133 kPa) in the right eye and 19 mmHg in the left eye. No obvious abnormalities were observed in the anterior segment of the right eye; Left eye: There is no conjunctiva congestion, and a subconjunctival hemispherical black mass can be seen at 11:00 above the nose, with a clear boundary, about 8 mm ×8 mm, about 3 mm away from the limbus, and nourishing blood vessels can be seen (Figure 1）。 Cornea transparent, sclera porcelain white, anterior chamber medium deep, subcorneal deposits (-), aqueous humor flash (-), iris texture clear, no abnormal pigmentation, pupil round, 3 mm in diameter, sensitive to light reflection, crystalline lens transparent. The dilated pupil examination of the fundus showed that the vitreous body of both eyes was transparent, and no obvious abnormality was found in the fundus. Auxiliary examination: Ocular ultrasound showed hemispherical solid lesions (8.6 mm ×2.8 mm ×8.1 mm) detectable in the peripheral bulbar wall of the left eye and nose, with clear boundaries and uneven internal echoes (Figure 2), color Doppler flow imaging can detect blood flow signals; Ultrasound biomicroscopy showed a solid subconjunctival mass above the nose of the left eye, about 7.3 mm ×7.01 mm ×2.24 mm in size, involving the sclera and choroid, with unclear boundaries and uneven internal echoes (Figure 3）； OCT, wide-angle fundus phase, orbital MRI, plain chest radiograph and abdominal B-ultrasound showed no obvious abnormalities.

In recent years, the use of collagen cross-linking with ultraviolet A and riboflavin is being developed universally due to its significance in the improvement of the mechanical strength of collagen fibers in clinical and basic research. It has been used in treating some corneal diseases including keratoconus, keratectasia and keratohelcosis. Thus, it might become a new treatment to prevent progressive myopia by strengthening scleral tissue. This article focuses on the effectiveness and safety of ultraviolet A-riboflavin cross-linking, and discusses the application prospect, focal points and problems related to cross-linking therapy. (Chin J Ophthalmol, 2018, 54:948-953)

Endothelial keratoplasty is a surgery that selectively replaces the diseased endothelium and reserves the normal corneal epithelial and stromal layers. It is now gradually replacing penetrating keratoplasty in treating endothelial dysfunction. Although endothelial cell loss exists after endothelial keratoplasty, the number of lost cells is obviously less than that of penetrating keratoplasty. The amount and function of corneal endothelial cells are important factors for maintaining corneal transparency and indicating the survival of the graft. Thus, the changes of corneal endothelial cell density after surgery are significant in predicting the prognosis. This article elaborates on the changes of endothelial cell density after endothelial keratoplasty and related influencing factors, aiming to provide reference and basis for clinical diagnosis and treatment. (Chin J Ophthalmol, 2018, 54:954-960)

The patient was a 4-year-old female. He was seen in Tianjin Eye Hospital because he found that the painless black mass in the medial canthus of his right eye was increasing for 1 year. The child had a full-term cesarean section, and no abnormalities were found in the whole body examination. Eye examination: visual acuity was 0.8 for the right eye and 0.6 for the left eye; IOP was 13.5 mmHg (1 mmHg =0.133 kPa) in the right eye and 12.0 mmHg in the left eye; The eyeballs of both eyes can move freely in all directions; The appearance of the right eye was normal, with no redness and swelling of the eyelid, no conjunctiva congestion, and a circular black mass with a diameter of about 5 mm was visible in the mons lacrimal, protruding about 4 mm from the surface of the conjunctiva. It was soft in texture, clearly defined, without tenderness, and had a certain degree of mobility. The surface of the mass was smooth but uneven (Quintessence Picture 1）； Anterior segment and fundus examination of other eyes showed no abnormalities. The left eye examination showed no abnormalities. After admission, the right eye caruncle tumor was resected, and histopathological examination was performed after operation (Quintessence Picture 2）。 Diagnosis: Pigmented nevus of the conjunctiva in the mons lacrimal of the right eye (compound nevus).