Volume 54 · Issue 04 · 2018

This issue focuses on the research progress of fundus diseases. The responsible editorial committee responsible for the planning, composition and review of this issue is Professor Xu Xun.

Fundus imaging technologies have been developing rapidly in recent years. Among these technologies, the Optical Coherence Tomography Angiography (OCTA) is particularly noteworthy. Unlike traditional angiography, OCTA features non-dye-injection and non-invasivion, and is capable of providing high-resolution 3D images of vascular flow in the retina and choroid in a matter of seconds. Its clinical value is being more and more recognized by retinal specialists. In this article, we will illustrate how OCTA will change our daily practice in four aspects, namely: (1) changing our understanding of the diseases, (2) helping us with differential diagnosis, (3) optimizing clinical service process, (4) redesigning treatment & follow-up process. (Chin J Ophthalmol, 2018, 54: 241-243)

In recent years, many randomized intervention studies in the field of ophthalmology were published in influential journals such as The Lancet. There have been different voices about these published articles. It is important for academic associations and societies to select the right articles and incorporate the fitting results into the national clinical guidelines based on the proper interpretation and understanding of both the articles and China's national conditions. Chinese ophthalmologists should actively carry out high-quality clinical researches to meet the needs of developing domestic clinical guidelines and to enhance the international influence of Chinese ophthalmology.(Chin J Ophthalmol, 2018, 54: 243-244)

After more than two years, the international Tear Film and Ocular Surface Association (TFOS) published the first edition of the international dry eye workshop (DEWS) Ⅰ Based on the method of evidence-based medicine, combined with the new understanding of dry eye in the past 10 years, the definition and classification, pathogenesis, epidemiology, diagnostic criteria and treatment principles of dry eye were systematically and comprehensively revised^[1,2]。 DEWS II was officially released in July 2017. In this paper, the definition and classification of dry eye in DEWS Ⅱ are interpreted.

In 2007, the international Tear Film and Ocular Surface Association (TFOS) published the first edition of the international dry eye workshop (DEWS) I. Unlike the American Academy of Ophthalmology, which compiles relevant guidelines only by ophthalmic clinicians, DEWS invited scholars and optometrists in the basic research field of dry eye to participate in the discussion and writing work at the time of compilation. The compilation of the new edition of DEWS (DEWS II) in 2017 carries on this tradition. At the end of 2015, the author of this article was invited by TFOS to participate in the revision of DEWS II with Professor Liu Guoguo of the Institute of Ophthalmology of Xiamen University on behalf of mainland China. During the compilation process, I deeply realized that the research in the field of dry eye treatment has developed rapidly in the past 10 years, and the research and development of small molecule drugs, diet and behavioral intervention oriented to individualized treatment are bound to change the existing dry eye treatment model in the future. This time, TFOS has comprehensively revised the chapter on the treatment and treatment of dry eye. Compared with DEWS Ⅰ, the content and text structure have changed greatly, which fully reflects the research progress in the field of dry eye treatment in recent years^[1]。 It should be noted that DEWS II is different from the general clinical diagnosis and treatment guidelines (guideline) and the recommended practice pattern (preferred practice pattern). The former is completed by clinicians, optometrists and basic research scholars, so some of them are still in the basic research or preclinical research stage, and cannot be used as a direct basis to guide clinicians' work.

To evaluate the efficiency of 23 G vitrectomy combined with preoperative subtenon injecfion of triamcinolone acetonide for treatment of rhegmatogenous retinal detachment associated with choroidal detachment.

A retrospective analysis. Forty-eight (16 males and 32 females, aged 57.3±13.9) consecutive patients (48 eyes) who were diagnosed with rhegmatogenous retinal detachment associated with choroidal detachment and received 23 G vitrectomy at the Eye Hospital of Wenzhou Medical University during January 2012 and January 2015 were enrolled. Twenty-three eyes were treated with subtenon injection TA 5 d before the planned 23 G vitrectomy (TA group). Twenty-five eyes were treated with dexamethasone 3 to 5 d before the planned vitrectomy (Dex group). Type-B ultrasonic, intraocular pressure, best corrected visual acuity examinations were conducted for all eyes on admission day, preoperatively and at 1 month, 3 month postoperatively, and during the last visit. The rate of reattachment, change of height of choroidal detachment, intraocular pressure, best corrected visual acuity, and the complication of the eyes between the two groups were compared. All patients were followed up at least half a year after the repair surgery.

The intraocular pressure of the TA group was higher than the Dex group[(8.58±3.83)mmHg vs. (6.70±2.49)mmHg (1 mmHg=0.133 kPa), (t=2.032)], and the height of choroidal detachment was lower in TA group [0.90(0.00, 3.84)mm vs. 4.03(1.05, 5.38)mm, Z=-2.569, P<0.05]. There is no statistic difference between the reattachment rate of the two groups [95.7%(22/23) vs. 76.0%(19/25), χ ²=2.304, P=0.129], but it seems it was better in TA group. The best corrected visual acuity results of the last visit was better in TA group than Dex group [(0.91±0.54) vs. (1.25±0.62), t=-2.034, P=0.048]. The rate of hypertention was higher in TA group than Dex group at 1 month, 3 month postoperatively(χ²=2.304, 5.648, P<0.05), while there was no statistic difference of hypertention rate during last visit between the two groups (χ²=0.006, P=0.941).

The treatment of 23 G vitrectomy combined with subtenon injection of triamcinolone acetonide can improve the intraocular pressure, reduce the height of choroidal detachment, and improve the best corrected visual acuity after the surgery, but it may cause heyertenion. (Chin J Ophthalmol, 2018, 54: 252-257)

To evaluate the relationship between the structure of macular region and prognosis after vitrectomy in idiopathic macular epiretinal membrane patients.

Retrospective case series study. The cases of 74 idiopathic macular epiretinal membrane patients (31 female patients, 43 male patients, aged 68.1±6.9) who received surgery treatment in our hospital during January 2013 and December were collected and analyzed. Ophthalmic routine examination and optical coherence tomography (OCT) have been conducted for all patients prior to operation. All eyes underwent vitecrtomy and macular epiretinal membrane peeling. During the 12 months follow up, the preoperative and postoperative data including best corrected visual acuity (BCVA), foveal thickness, changes of morphology in ellipsoid zone were observed and analyzed. All the patients were divided into two groups, continuous group (52 patients) and discontinuous group (22 patients), based on the preoperative continuity status of ellipsoid zone. The data of preoperative macular retinal thickness, the relationship between age and course of the disease, preoperative BCVA and postoperative BCVA were analyzed statistically with repeated ANOVA method. The postoperative BCVA were analyzed statistically with t test mtehod, based on the different grouping of continuity status of ellipsoid zone.

The preoperative LogMar BCVA, and the postoperative LogMAR BCVA of 1 month, 3 month, 6 month and 12 month after operation were 0.59±0.26, 0.63±0.34, 0.46±0.22, 0.45±0.23, 0.41±0.23 (F=25.122, P<0.05) respectively. The preoperative foveal thickness, and the postoperative foveal thickness of 1 month, 3 month, 6 month and 12 month after operation were (468.12±73.07), (371.57±57.09), (320.57±65.88), (294.85±69.36), (283.5±66.56)μm (F=8.802, P<0.05), the difference between the figures are of statistical significance. The postoperative BCVA of continuous group (0.34±0.27) improved significantly, as compared to the BCVA of discontinuous group (0.62±0.24) (t=-4.209, P<0.05). There is no obvious relationship between the degree of preoperative macular edema and postoperative visual function (r=0.015, P> 0.015). Seven patients still have macular edema one year after surgery.

The postoperative visual function in patients with idiopathic macular epiretinal membrane has negative correlation with preoperative thickness of fovea, and has positive correlation with continuity of ellipsoid zone. (Chin J Ophthalmol, 2018, 54: 258-262)

To study the clinical and imaging features of autosomal recessive bestrophinopathy (ARB).

Retrospective study. The clinical and imaging data of 14 participants were analyzed in using autofluorescence (AF), fluorescein angiography (FA) and spectral-domain optical coherence tomography (SD-OCT). Ten patients were screened for mutations in BEST1 gene.

Retinopathy of ARB were shown as bilaterally and circularly distributed yellow subretinal deposits in the mid-peripheral and posterior retina, which was observed more clearly by AF and FA. The abnormalities were observed as hyperreflection between the sub-retinal pigment epithelium space as well as the subretinal space by SD-OCT imaging. All of the patients showed serous retinal detachment, and 4 of them were found to have intraretinal schisis. Other ocular complications include choroidal neovascularization (CNV) and angle closure glaucoma (ACG) were also found in the patients. Genetic examinations showed that the mutations are compound heterozygous in five patients, homozygous in one patient and heterozygous in only one of the rest 4 patients.

The combination of clinical and retinal imaging data may facilitate the diagnosis of ARB. Physicians should be cautious of the vision-threatening complications of the disease. (Chin J Ophthalmol, 2018, 54: 263-269)

To evaluate the efficacy of vitrectomy and etiological diagnosis in the treatment of fungal endophthalmitis.

A retrospective survey was done on the clinical manifestation, etiological diagnosis and treatment efficacy of 15 patients (15 eyes) who had been diagnosed with fungal endophthalmitis at the inpatient department of Peking Union Medical College Hospital during 2002-2015. A total of 15 eyes of 15 patients, 3 male and 12 female patients, were included in this study. The mean age of the patients was (45.8±15.3) years. Among the 15 eyes, 12 (12 patients) were diagnosed with endogenous fungal endophthalmitis and 3 (3 patients) were diagnosed with exogenous fungal endophthalmitis. Fourteen eyes have been misdiagnosed with uveitis, systematic or local application of glucocorticoid and/or immunosuppressor have been conducted on the patients which resulted in exacerbation. Baseline visual acuity: light perception in 2 eyes, hand movement for 12 eyes, and 1 eye of 0.1. Six eyes showed slight inflammatory reaction in anterior chamber, four eyes showed moderate inflammatory reaction in anterior chamber, while five eyes showed severe inflammatory reaction with hypopyon in anterior chamber. B-Scan ultrasound examination showed inflammatory vitreous opacity in all 15 eyes, combined proliferative vitreoretinopathy (PVR) were found in 11 eyes, retinal detachment were found in 10 eyes, which include 6 cases of tractional retinal detachment, 1 case of exudative retinal detachment, and 3 cases of retinal and choroid detachment. Forty eyes underwent vitrectomy, 1 eye underwent intravitreal injection. Nine eyes were processed with silicone oil tamponade, one eye was processed with C₃F₈ tamponade. At the beginning of the operation, vitreous fluids were collected for preparing smears which were later used for fungus culture and drug susceptibility testing.

According to the smear results of vitreous fluid, fungal hyphae and spores were found in 10 eyes. The fungus culture indicated positive results in 12 eyes, including candida albicans in 6 eyes, fusarium, candida parapsilosis, paecilomyces lilacinus, asoergullus terreus, mulan candida and aspergillus in 1 eye respectively. Based on etiological diagnosis, 14 eyes received amphotericin B intraocular injection during operation, and 9 patients received fluconazole (venous transfusion or oral administration), 2 patients received voriconazole through venous transfusion or oral administration, one patient received itraconazole through oral administration. All 15 eyes received local application of amphotericin B eyedrop or fluconazole eyedrop. The intraocular inflammations in all 15 eyes were mitigated. The visual acuity improved in 6 eyes, remained unchanged in 4 eyes, and reduced in 5 eyes. Postoperative visual acuity achieved 0.1 to 0.15 in 2 eyes, 0.01 to 0.04 in 2 eyes, CF in 2 eyes, HM in 4 eyes, LP in 2 eyes, and NLP in 3 eyes. The retina of 5 eyes remained in position, the retina of 2 eyes reattached, the retina of 2 eyes failed to reattach. Recurrent retinal detachment happened in the other 6 eyes, 5 of which received reoperation. Eventually, the retina of 10 eyes reattached, and the retina of the 5 eyes failed to reattach.

Vitrectomy is an effective method for treatment of fungal endophthalmitis. The positive rates of vitreous smear and fungus culture were really high. Application of sensitive anti-fungal drugs based on etiological diagnose can improve therapeutic level. (Chin J Ophthalmol, 2018, 54: 270-276)

To evaluate the adhesion effect of tissue engineering retinal nerve scaffolds modified with biological glue.

Experimental study. To fabricate a biological glue by blending laminin, collagen Ⅳ, entactin and HSPG₂ with phosphate-buffered saline (PBS) buffer solution, scaffolds were then modified with the biological glue of various concentration levels (10 μl/cm ², 20 μl/cm ², 30 μl/cm ² and 40 μl/cm ²). The effects of various concentration levels glue on inducing scaffold adhesion were analyzed after 24 h. Cell count method and CCK-8 kit were used to assess the effects of biological glue on cell growth and toxicity. Then the scaffolds modified with or without glue were transplanted into rabbit's retina by 23 G pars plana vitrectomy. Intraocular pressure(IOP) and retina examination were assessed by ICare, fundus photograph and OCT. The adhesion effects of various concentration levels glue were analyzed bychi-square test. The cell adhesion rate of different scaffolds was analyzed by Mann-Whitney U test. One-Way ANOVA was used to compare the cell survival rate of different scaffolds. After transplantation, the IOP variance of rabbits was analyzed by repetitive measurement deviation analysis.

Compared with the control groups, the maximum adhesion rate of the biological glue was 91.7% (χ²=8.79, P<0.05) at 30μl/cm² concentration level. After 24h of cultivation, cell adhesion rate of glue-scaffold group (86.85%) was significantly higher than that of pure scaffold group (13.78%, U=0.01, P<0.05), while there was no significant difference between the cell survival rates of the two groups (F=7.235, P=0.11). There was no significant difference (F=79.16, P=0.07) between the IOP of viscosity modified group [(18.4+0.93) mmHg (1 mmHg=0.133 kPa)] and non- modified group [(17.1±0.04)mmHg]. The retina adhesion rate of viscosity modified scaffold was 80% at 7 days postoperatively, and the fundus examination showed no inflammatory response in retina and vitreous cavity.

This study showed that the biological glue has favorable viscosity modifying effect on tissue engineering neural retina scaffolds, which is beneficial for the biological material transplantation. (Chin J Ophthalmol, 2018, 54: 277-282)

To investigate the common causes, onset age of vision impairment and complications of sensory strabismus, and to explore the effective surgical methods for sensory strabismus and associated complications.

In this retrospective study, there were 948 cases of surgical treatment for sensory strabismus from 2005 to 2015 in Tianjin Eye Hospital, including 822 cases of sensory exotropia and 126 cases of sensory esotropia. Causative disease, onset age of vision impairment, eye movement, horizontal and vertical deviation and surgical methods were evaluated. Statistical methods included independent samples t test, Mann-Whitney U test and chi-squared test.

Congenital or traumatic cataract was the most common cause of sensory strabismus. Anisometropia, optic atrophy, corneal opacity and retinal detachment were also primary reasons. The mean onset age of vision impairment was (2.3±4.2) years in the sensory esotropia group and (8.8±9.0) years in the exotropia group, and a positive correlation was found between the two groups (t=-8.00, P<0.01). Sensory strabismus occurred with A- or V-pattern in 100 cases (10.5%), nystagmus in 42 cases (5.1%), DVD in 57 cases (6%) and oblique overaction in 134 cases (14.1%;including 54 cases with A- or V-pattern). No statistically significant difference existed between the relevance ratio of A- or V-pattern, oblique overaction and the type of strabismus (χ²=0.13, 0.04; P>0.05), but significance difference existed between the relevance ratio of nystagmus, DVD and the type of strabismus (χ²=48.33, 12.04; P<0.01).

The leading cause of sensory strabismus was cataract. The onset age of vision impairment was earlier in the sensory esotropia group than the exotropia group. Patients were more likely to suffer from DVD and nystagmus in the sensory esotropia group than the exotropia group. Surgeons should make a comprehensive assessment before surgery to design a rational surgical procedure. (Chin J Ophthalmol, 2018, 54: 283-287)

This study investigates the effect of simplified and traditional Chinese character on accommodative microfluctuation in young adult myopes and emmetropes.

Prospective cohort study. Based on refractive errors, Young adult candidates (18-28 years) were classified into two groups based on their spherical equivalent degrees: emmetropes (n=18), myopes (n=18). Four different reading targets (12pt size simplified and traditional Chinese characters, and 8pt size simplified and traditional Chinese characters) were displayed on computer screen collectively for 135s. The accommodative microfluctuation of the candidates were measured using the free space Grand-Seiko WAM-5500 autorefractor.

The results indicated that the type of character (simplified and traditional) had significant influence on accommodative microfluctuation. For myopic candidates, the accommodative microfluctuation for traditional Chinese character was greater than that for simplified Chinese character [traditional Chinese character: (0.35±0.17) D, vs. simplified Chinese character: (0.29±0.11) D, t=2.556, P=0.017], however as for emmetropic candidates, the difference between the accommodative microflucuation for the two types of characters was of no statistical significance [traditional Chinese character: (0.24±0.11) D, vs. simplified Chinese character: (0.24±0.12) D, t=0.004, P=0.996]. There was a difference between emmetropic and myopic candidates in terms of accommodative microfluctuation for traditional Chinese character, myopes had greater accommodative microfluctuation than emmetropes (t=3.140, P=0.02). However the difference between emmetropic and myopic candidates in terms of accommodative microfluctuation for simplified Chinese character was of no statistical significance (t=1.866, P=0.066).

The results of the study indicated that myopes were more susceptible than emmetropic in accommodative microfluctuation when reading traditional Chinese character of high spatial frequency. (Chin J Ophthalmol, 2018, 54: 288-293)

The patient was a 6-year-old male. The abnormal fundus of his right eye was found for nearly 1 month, and he went to Beijing Tongren Eye Center, Beijing Tongren Hospital affiliated to Capital Medical University on August 10, 2017. Two months ago, the patient suffered from chickenpox, and his eyes were red and itchy, which improved after antiviral treatment in the local hospital. One month ago, after a cold and fever, both eyes appeared red and itchy again, and the local hospital examination found that the right fundus was abnormal. Perinatal condition was good with no other previous medical history and no family history of related ophthalmopathy. Eye examination: visual acuity of right eye 1.0, left eye 0.8; IOP was 9 mmHg (1 mmHg =0.133 kPa) in the right eye and 9 mmHg in the left eye. Anterior segment examination showed no abnormalities. Fundus photography showed a flat, torpedo-shaped lesion about 1 PD on the temporal side of the macula in the right eye, pale and internally uneven, with clear boundaries, its tip pointing to the macula, with a transverse diameter of about 3 PD and a longitudinal diameter of about 2 PD (Figure 1), the retinal vessels on the surface of the lesion were normal. No abnormalities were observed in the left fundus (Figure 2）。 Fundus autofluorescence shows that the right eye lesion is uniformly hypofluorescent, and a circle of hyperfluorescence can be seen around it, and the left eye is normal (Figure 3）。 OCT examination showed that the neuroepithelial layer in the lesion area of the right eye was detached, there was a small interlaminar cystic cavity in the inner retina, the structure of the outer retina was disordered, the RPE layer was missing, the lower choroid was depressed and thinned, and the reflex was slightly enhanced (Figure 4）； No abnormalities were observed in the macular area (Figure 5）。 OCT examination of left eye showed no abnormalities. Diagnosis: torpedo-like maculopathy in the right eye. It is recommended that the patient be reviewed regularly and undergo laser treatment if necessary.

A 15-year-old male was admitted to the Department of Urology of the 309th Hospital of the People's Liberation Army due to dizziness and fatigue with increased serum creatinine for 2 weeks. The blood urea nitrogen was 34.22 mmol/L, creatinine was 981 μ mol/L, occult blood +, urine protein + + +, and hemoglobin was 105 g. Urinary tract ultrasound examination showed that the size of both kidneys was reduced, the left kidney was about 3.4 cm ×3.7 cm ×6.1 cm, and the right kidney was about 3.2 cm ×3.5 cm ×6.3 cm, the cortex was thinned, the diffuse echo of the parenchyma was enhanced, the cortex and medulla were unclear, and the collective system was disordered, suggesting kidney atrophy and diffuse kidney lesions. He was diagnosed as a renal insufficiency uremic stage and came to an ophthalmologist consultation to rule out Alport syndrome. There was no hearing loss in the otolaryngology consultation. The patient had poor vision since childhood. When he was 3 years old, he went to a hospital and was diagnosed with optic nerve dysplasia in his right eye. He was treated with short-term oral traditional Chinese medicine. There was no history of ocular trauma, kidney disease and family history of ocular disease. Ophthalmic examination: the visual acuity of the right eye was 0.1 and the visual acuity of the left eye was 0.4, both of which could not be corrected. Both eyes had horizontal nystagmus, normal anterior chamber, equal size and round pupils, and no abnormal morphological changes in the lens. Fundus examination: Both eyes have large optic discs, deep depression of optic discs, defect of central blood vessels, replaced by ciliary blood vessels located at the edge of optic discs, and normal retinal blood vessels. Fundus changes are similar to those of optic nerve head defect or morning glory syndrome fundus changes (Figure 1）。 OCT showed that the foveal thickness of the right eye was normal, the reflection was visible, the omentum around the fovea was atrophied and thinned, the IS/OS light band was discontinuous, and the RPE reflection light band was normal. The shape and thickness of the macular area in the left eye were normal, the foveal reflection was visible, the IS/OS layer and the RPE reflected light band were normal (Figure 2）。 Diagnosis: papillorenal syndrome (PRS) in both eyes. There is no special treatment in ophthalmology, and the nephrology department is recommended to treat renal insufficiency. The patient underwent renal transplantation of relatives, and the renal function recovered well after operation. Genetic analysis showed that the patient's PAX2 gene had a known pathogenic mutation c.69_70insG (p.Leu23LeufsX31; Het) (Figure 3）。

Since Jensen reported the first case of intraocular lens opacity in 1994^[1]Current reports cover several major materials used on the market, including silicone gels, polymethyl methacrylate, hydrophobic and hydrophilic acrylate intraocular lenses^[2]and is the most common cause of hydrophilic acrylate lens removal^[3]。 At present, most of the reported intraocular lens opacity is simple cataract extraction surgery. A relatively rare case of intraocular lens opacity (Akreos, Bausch & Lomb, USA) in patients undergoing cataract extraction combined with vitrectomy admitted to Sir Run Run Shaw Hospital Eye Center affiliated to Zhejiang University School of Medicine is reported as follows.

The patient was a 54-year-old male. He was treated in the Department of Ophthalmology of Peking Union Medical College Hospital on April 13, 2017 due to high fever for more than 20 days, swelling and pain in his left eye with visual acuity loss for 10 days. Previous type 2 diabetes for 10 years, without regular control and monitoring of blood glucose.

Perfluorocarbon liquid, also known as heavy water, is an extremely useful auxiliary tool in clinical vitreoretinal surgery. Heavy water can remain in different locations in the eye after surgery (Quintessence Picture 1）。

Acute retinal necrosis is an uncommon but devastating and potentially blinding ophthalmopathy featured with unfavorable prognosis as the lesions tend to develop rapidly in a circumferential way in few days. Therefore timely diagnosis and early treatment are of great significance. The polymerase chain reaction test on intraocular fluid can improve specificity and sensitivity of the etiological detection for acute retinal necrosis. Etiology results included in the diagnostic criteria is favorable for etiological diagnosis. Current treatment for acute retinal necrosis is generally based on systemic antiviral therapy, and supported by hormone and antithrombotic drugs, while surgical treatment should be considered when the disease progresses. This article reviews the research progress on the diagnosis and treatment of acute retinal necrosis in an effort to improve the diagnosis and treatment performance of acute retinal necrosis. (Chin J Ophthalmol, 2018, 54: 306-311)

Retinal degeneration (RD) is a common eye disease which may result in blindness. At present, there is no effective clinical treatment for RD. It is known that apoptosis causes the occurrence and development of retinal degeneration, therefore antiapoptotic/antioxidative treatment has always been the focus in the treatment of RD. There are many kinds of antioxidant drugs, among which natural antioxidants are featured with reliable sources, high safety and less side effects. Hence researchers across the world made tremendous efforts in finding the safe and effective natural antioxidants. This paper focuses on the research progress of natural antioxidants in the treatment of retinal degeneration, in an effort to provide some valuable reference for clinical research. (Chin J Ophthalmol, 2018, 54: 312-315)

Idiopathic optic neuritis (ON) is an idiopathic inflammatory disease of the optic nerve. The two most common types of ON are multiple sclerosis related ON and neuromyelitis optica related ON. But so far the precise mechanisms of different types of ON have been unclear and treatments are not satisfactory. Animal disease models play critical roles in the disease mechanism research. On the other hand, with more understanding about the etiology and mechanism of ON, new models mimicking different types of ON are under development. This article reviews the recent research progression of animal models of multiple sclerosis related ON and neuromyelitis optica related ON and the model evaluation methods. (Chin J Ophthalmol, 2018, 54: 316-320)