Volume 52 · Issue 01 · 2016

Looking back at the past 2015, the indicators of various journals of this journal continue to improve, ranking first among ophthalmology journals. This is the result of the joint efforts of all ophthalmology colleagues, and we are proud of it! In the future years of running the journal, we will continue to adhere to the tenet of respecting science, seeking truth and being pragmatic, and adhere to the review system of "three reviews and five determinations" to provide better academic content for the majority of ophthalmologists. At the beginning of the new volume, Professor Xie Lixin, academician of Chinese Academy of Engineering, wrote the foreword "Future Development Trend of Ophthalmology", discussing the future development direction of ophthalmology from several aspects, such as scientific and technological talents and teams, information networks and telemedicine, stem cells and regenerative medicine, molecular targeting and precision medicine, hoping to help colleagues in ophthalmology to grasp the future development direction.

Since the 21st century, with the rapid development of science and technology, information network, biotechnology, stem cell and regenerative medicine, molecular targeted therapy, etc. have successively appeared subversive progress and applicable development prospect^[1]。 These technologies have contributed to the future development of ophthalmology, and at the same time, they have also brought new opportunities and challenges to the ophthalmology community. At the beginning of 2016, I discussed the future development of ophthalmology through Chinese Journal of Ophthalmology from several aspects, such as scientific and technological talents and teams, information networks and telemedicine, stem cells and regenerative medicine, molecular targeting and precision medicine, hoping to make more people pay attention to its direction, which will be beneficial to the progress of ophthalmology in China.

In recent years, new technologies and ideas of modern ophthalmology and optometry have emerged. Based on the wavefront technology and its derivatives, the traditional concepts of refractive errors and vision correction have been redefined and supplemented. Human optical quality can be evaluated effectively and objectively. Moreover, the studies about the wavefront vision correction have shown preferable vision correction results. Application of these modern methods of wavefront refraction and correction offers important opportunities for better optical quality and visual performance in corneal refractive surgery. It also provides a foundation for creating novel clinical diagnosis and treatment options in vision correction. (Chin J Ophthalmol, 2016, 52: 10-14)

Optical correction is the basis of optometry. Optimized visual quality through optical correction is more challenging and more scientific as visual quality is becoming more closely related to social integration and development. There are many visual quality problems associated with various non-surgical optical correction methods in different aspects and degrees. This article discusses in depth some of the problems regarding optical correction with spectacles for different age groups, from children to seniors. The use of soft contact lenses, rigid gas-permeable contact lenses, and orthokeratology lenses is also evaluated. Moreover, some suggestions and recommendations on promoting visual quality through optical correction are provided. (Chin J Ophthalmol, 2016, 52: 5-9)

This consensus is applicable to femtosecond laser small incision corneal stromal lens removal surgery carried out by qualified medical units at all levels in China.

To discuss the accuracy of intraocular pressure (IOP) values measured after small incision lenticule extraction (SMILE), analyze the corneal biomechanical influencing factors of IOP measurement before and after SMILE, and regress the equation of IOP variation for estimating actual IOP.

In this clinical controlled study, 116 eyes (60 patients) with myopia and myopic astigmatism undergoing SMILE surgery were included. The ocular response analyzer, noncontact tonometer (NCT), and Pentacam system were used to measure the IOP preoperatively and at 3 months postoperatively, acquiring IOPg, IOPcc, NCT, Ehlers, Shah, Dresden, Orssengo, and Kohlhaas. The eight IOPs before and after surgery were analyzed with the paired t-testing. The Pearson correlation coefficient and Spearman correlation coefficient were used to evaluate the relationship between preoperative and postoperative IOPs and influencing factors. The regression analysis of IOP variation ΔNCT and influencing factors was performed with the multiple linear regression analysis.

The Shah program in Pentacam showed no difference between preoperative and postoperative IOP values (t=-0.08, P=0.940). There was significant difference in the other IOPs before and after SMILE (P<0.001). The preoperative IOPg, IOPcc, and NCT were correlated with the preoperative CRF (r=0.674, 0.248, 0.710,P<0.01). The preoperative IOPg, NCT, Ehlers, and Shah were correlated with the preoperative CCT (r=0.260, 0.259, -0.418, -0.245,P<0.01). A moderately positive correlation was shown between the preoperative and postoperative IOPs (r≥0.5,P=0.000). The postoperative IOPg, Ehlers, Shah, and Dresden were correlated with the postoperative CCT (P<0.05). The postoperative IOPg, NCT, Orssengo/Pye, and Kohlhaas were correlated with the postoperative CRF (r=0.707, 0.549, 0.276, 0.346,P<0.01). The postoperative IOPg, IOPcc, NCT, Ehlers, and Shah were correlated with the postoperative CH (r=0.296, -0.366, 0.270,-0.349,-0.197,P<0.05). The regression equation of IOP variation ΔNCT and influencing factors was ΔNCT=-4.618+ 0.389NCT _pre-0.431SC (SC was the algebraic sum of sphere and cylinder,R²=0.366, P=0.000).

The evaluation of IOP values after SMILE should not only take the preoperative IOP and postoperative CCT into consideration, but also the corneal biomechanics which may affect the postoperative IOP. IOPcc and Pentacam corrective IOPs are relatively reliable after SMILE. Among the five correction methods of Pentacam system, Shah program can be used as the first choice for correct IOP after SMILE. The regression equation of the postoperative corrected NCT, NCT_{post corrected}=NCT_{post measured} +0.389NCT_pre-0.431SC-4.618, may be used to evaluate the real postoperative IOP in clinical practice. (Chin J Ophthalmol, 2016, 52: 22-29)

To investigate the correlations between corneal sensation, tear meniscus volume, and tear film osmolarity after femtosecond laser-assisted LASIK (FS-LASIK) surgery.

In this prospective clinical study, 31 patients undergoing FS-LASIK for myopia were recruited. The upper and lower tear meniscus volumes (UTMV and LTMV) were measured by customized anterior segment optical coherence tomography, tear film osmolarity was measured by a TearLab Osmolarity test device, central corneal sensation was measured by a Cochet-Bonner esthesiometer preoperatively, at 1 week, 1 and 3 months postoperatively. Repeated measures analysis of variance was used to evaluate whether the tear film osmolarity, tear meniscus volume, and corneal sensation were changed after surgery. The correlations between these variables were analyzed by the Pearson correlation analysis.

The tear film osmolarity was (310.03 ± 16.48) mOsms/L preoperatively, (323.51 ± 15.92) mOsms/L at 1 week, (319.93 ± 14.27) mOsms/L at 1 month, and (314.97±12.91) mOsms/L at 3 months. The UTMV was (0.42±0.15), (0.25± 0.09), (0.30±0.11), and (0.35±0.09) μL, respectively; the LTMV was (0.60±0.21),(0.37±0.08), (0.44± 0.14), and (0.52±0.17) μL, respectively. The tear film osmolarity was significantly higher at 1 week and 1 month postoperatively compared with the baseline ( P=0.001, 0.004), and reduced to the preoperative level at 3 months (P=0.573). The UTMV, LTMV, and corneal sensation values presented significant decreases at all postoperative time points (all P<0.05). The Pearson correlation analysis showed the postoperative UTMV had a weak relationship with corneal sensation at 1 week after surgery (r=0.356,P=0.005). There were significant correlations between the preoperative LTMV and corneal sensation at 1 week, 1 and 3 months (respectively, r=0.422, 0.366, 0.352;P=0.001, 0.004, 0.006). No significant correlations were found between the tear film osmolarity, tear meniscus volume, and corneal sensation after surgery (all P>0.05).

The tear film osmolarity, tear meniscus volume, and corneal sensation became aggravated due to the FS-LASIK surgery procedures. There were significant correlations between the preoperative tear meniscus volume and recovery of corneal sensation early after surgery. A higher tear meniscus volume before surgery may contribute to a faster corneal sensation recovery. (Chin J Ophthalmol, 2016, 52:30-35)

To investigate the incidence rate, classification, and management of difficulties in lenticule extraction during small incision lenticule extraction (SMILE) with the continuous curvilinear lenticulerrhexis (CCL) technique, and surgical safety and efficacy.

Retrospective study. A total of 342 continuous subjects (680 eyes) received surgical treatment by the same surgeon using the SMILE-CCL technique. The separation was performed only between the cap and anterior surface of the lenticule (8 to 2 o'clock) and at the edge between the cap and posterior surface of the lenticule (1 o'clock). The lenticule was then extracted in a clockwise motion using the CCL technique. Cases with lenticule extraction difficulties were observed through surgery videos. Classification and management of the difficulties were recorded. The rate of intact lenticule extraction was calculated.

Twenty-two subjects (22 eyes) had lenticule extraction difficulties. The rate was 3.24%. No difficulty was found in side cut lifting. The microforceps grip loss occurred more than once in five eyes. It was difficult to separate the cap and anterior surface in 12 eyes. One eye had a microdefect in the margin of the lenticule. Five eyes were observed to have single side tearing of side cut. No eyes had double sides tearing of side cut. The microforceps were changed when grip loss occurred more than once. When there were separation difficulties, the pace of lenticule extraction was slowed down, with tearing through the tangential direction of the circle (clockwise). The conventional technique was used in three cases with severe difficulties. All lenticules were successfully extracted from the 22 eyes (100%). Uncorrected visual acuity was ≥1.0 in all eyes at 1 day after surgery. The safety index (the ratio between best corrected visual acuity at 1 month and preoperatively) was 1.11. The efficacy index (the ratio between uncorrected visual acuity at 1 month and preoperative best corrected visual acuity) was 1.04.

Difficulties in lenticule extraction occur during SMILE-CCL with a low incidence. Various difficulties can be managed with different techniques. There are no extra effects on surgical safety and efficacy. It is safe and effective to switch back to the conventional technique when severe lenticule extraction difficulties occur. (Chin J Ophthalmol, 2016, 52:36-40)

To explore the incidence of intraoperative and early postoperative complications associated with the WaveLight FS200 femtosecond laser-assisted flap creation in LASIK surgery.

A consecutive series of 400 patients (786 eyes) who underwent LASIK using the WaveLight FS200 femtosecond laser from March 2011 to December 2012 were included in this retrospective study. Intraoperative and early postoperative complications were described and analyzed.

The intraoperative complications included suction loss (two eyes, 0.25%), incomplete flap creation (one eye, 0.13%), severe opaque bubble layers (three eyes, 0.38%), anterior chamber gas bubbles (eight eyes, 1.02%), skip lines (12 eyes, 1.53%), and corneal epithelial defects (eight eyes, 1.02%). The early postoperative complications included canal bleeding (eight eyes, 1.02%), diffuse lamellar keratitis (23 eyes, 2.93%), haze (six eyes, 0.76% ), and flap dislocation (one eye, 0.13% ).

Intraoperative and early postoperative complications of LASIK using the WaveLight FS200 were relatively mild. All patients could obtain satisfactory clinical results with proper treatment. (Chin J Ophthalmol, 2016, 52:41-46)

To objectively assess and compare comprehensive optical quality among adults at different ages.

In this cross-sectional study, there were 432 subjects (432 eyes) aged from 20 to 70 years with best corrected visual acuity (BCVA) better than 4.9. If both eyes of a subject had equal BCVA, one eye was selected randomly. Otherwise, the eye with better BCVA was chosen. The patients were divided into 5 groups at an age interval of 10 years. The optical quality analysis system Ⅱ (OQASⅡ) was used to measure the following optical quality parameters: the modulation transfer function cutoff frequency (MTF_cutoff), the Strehl ratio, three OQAS values (OV100%, OV20%, and OV9%), and the objective scatter index (OSI). Each optical quality parameter was compared among different groups by One-way ANOVA.

In the groups of 20-29 years, 30-39 years, 40-49 years, 50-59 years, and 60-69 years, the MTF_cutoff was (43.91±7.43), (40.93±9.92), (37.16±9.04), (36.69±7.87), and (28.52±8.31) cpd, respectively; the Strehl ratio was 0.26±0.06, 0.24±0.06, 0.20±0.05, 0.20±0.04, and 0.16±0.04, respectively; the OV100% was 1.47±0.24, 1.36±0.33, 1.24±0.30, 1.22±0.26, and 0.96±0.28, respectively; the OV20% was 1.51±0.33, 1.40±0.38, 1.22±0.36, 1.20±0.28, and 0.91±0.32, respectively; the OV9% was 1.14±0.26, 1.41±0.40, 1.20± 0.37, 1.18±0.28, and 0.89±0.28, respectively; the OSI was 0.42±0.24, 0.53±0.32, 0.54±0.34, 0.54±0.26, and 1.06±0.56, respectively. There were significant differences in the mean values of MTF_cutoff, Strehl ratio, OV100%, and OV20% among groups (P<0.05), except for the groups of 40-49 years and 50-59 years (P>0.05). The OV9% was significantly different among groups (P<0.05), except for the groups of 20-29 years, 40-49 years, and 50-59 years (P>0.19). The OSI was also significantly different among groups (P<0.05), except for the groups of 30-39 years, 40-49 years, and 50-59 years (P>0.70).

The comprehensive optical quality in the young healthy population is better than the old, except for a plateau in the middle-aged population. (Chin J Ophthalmol, 2016, 52:47-50)

To investigate the theoretical basis and practical limitations of the existing calculation formulas in the evaluation of ametropic state.

The evaluation indicators and their calculation parameters of ametropia were analyzed by using the reduced schematic model eye, the paraxial imaging principle, and the dimension laws.

The existing formulas resulted from the reduced object vergence of object distance and image distance relation. Regarding the two measurement indicators of the existing formulas, diopter was misused for refractive power. "Ametropia degree" was a non-standard diction. Both of them were not suitable as the evaluation indicators. The outcomes of the existing formulas and their related plus or minus sign rules showed refractive corrections instead of refractive errors proper. For refractive errors, there was no suitable evaluation indicator.

In the evaluation of ametropic state, there are fundamental problems in the existing formulas resulting from the reduced object vergence. The measurement indicators and their dimensional units are confused and misused. The calculation results refer to the refractive corrections only. The evaluation indicators for ametropia need to be further discussed. (Chin J Ophthalmol, 2016, 52: 51-55)

The patient was a 26-year-old male. On January 28, 2013, he was hospitalized for the first time in the Department of Ophthalmology, Yuhuangding Hospital, Yantai, because his right eye was occluded for 6 months. Being in good health. There were no abnormalities in the whole body examination. Ophthalmic examination: corrected visual acuity in right eye 0.03 (-4.00 DS-1.25 DC ×5°), corrected visual acuity of left eye 1.0 (-4.50 DS), transparent cornea in both eyes, normal anterior chamber, transparent lens in both eyes after cycloplegia, no abnormal morphology, mild opacity of vitreous body, retinal detachment on the temporal side and lower side of right fundus, involving macular area, multiple lattice-like degeneration areas of 360° peripheral retina and more than 10 retinal atrophic holes, peripheral retina detachment below left fundus, and multiple adjacent atrophic holes of the retina at 5 points. IOP was 10 mmHg (1 mmHg =0.133 kPa) in the right eye and 16.8 mmHg in the left eye. Diagnosis: Rhegmatogenous retinal detachment in both eyes, vitreous opacity in both eyes, refractive error in both eyes. After admission, vitrectomy + stripping + intraocular laser photocoagulation + silicone oil filling in the right eye and extrascleral cushion pressure + condensation in the left eye were performed, and the retinas of both eyes were repositioned after operation. One month after discharge, the patient was admitted for the second time on March 5 due to recurrent retinal detachment in his right eye. Ophthalmological examination: the cornea of both eyes was transparent, the anterior chamber was normal, the lens of both eyes was transparent after cycloplegia, and there was no abnormal shape. There was no obvious emulsification of silicone oil in the vitreous cavity of the right eye, and the retina in the lower peripheral part of the right eye was superficially detached. Two round atrophic holes were seen in the detachment area. On March 7, he underwent scleral cerclage + external cushion pressure + condensation in his right eye, and was cured and discharged. The corrected visual acuity of his right eye at discharge was 0.1 (+5.00 DS-1.75 DC ×2°).

The patient was a 40-year-old male. Due to the rash for 45 days, aggravated with fever for 25 days, he went to Beijing Ditan Hospital on January 9, 2010. And admitted to the hospital for treatment with immunodeficiency syndrome, lymphoma, syphilis and rash (syphilis rash). During hospitalization, due to red left eye, accompanied by mild pain and discomfort, I had my first ophthalmology consultation on January 14, 2010, and then I was reviewed once a week for a total of 3 times. Ophthalmological examination: visual acuity: right eye 1.0, left eye 0.25, intraocular pressure: right eye 13 mmHg (1 mmHg =0.133 kPa), left eye 10 mmHg Basal tear secretion test results: right eye 12 mm/5 min, left eye 10 mm/5 min, previous radial keratotomy in both eyes for 10 years. Visual field: visual field defect connected to the nipple in the left eye. Slit lamp microscopy: gray-white flat bulge with a diameter of 12 to 13 mm was seen on the median-temporal side of the bulbar conjunctiva above the left eye, with a height of about 2.5 mm, with a smooth surface and a cartilage-like texture. The bulbar conjunctiva was congested (+) and edema (+ +) from 12: 00 to 8: 00, and subconjunctival hemorrhage was seen near 6: 00. Gray-white cotton wool spots were seen in the retina of the posterior pole of the right eye, which was a typical human immunodeficiency virus (HIV) retinopathy, and no other abnormalities were observed. Ophthalmological diagnosis: syphilitic conjunctival chancre in the left eye and HIV retinopathy in the right eye. Ophthalmic treatment: The left eye was given 0.3% tobramycin eye drops 4 times/d and erythromycin eye ointment was applied.

The patient was a 57-year-old male. Due to night blindness and photophobia in both eyes for more than 5 years, he went to Beijing Tongren Eye Center, Beijing Tongren Hospital affiliated to Capital Medical University on March 1, 2013. The patient underwent cataract extraction in both eyes 3 years ago. Other medical history is denied, family medical history is denied. Ophthalmic examination: visual acuity of right eye 0.02, left eye 0.1; IOP in the right eye was 11.9 mmHg (1 mmHg =0.133 kPa) and 12.4 mmHg in the left eye; There was no congestion in the bulbar conjunctiva of both eyelids; Corneal clearance in both eyes; Deep in the anterior chamber of both eyes; Tyndall sign (-); The pupils of both eyes are equal in size and round, which are directly and indirectly sensitive to light reflection; The intraocular lenses of both eyes were in place, and the posterior capsules of the lenses of both eyes were transparent. Vitreous opacity in both eyes. Fundus examination of both eyes: the papilla boundary of both eyes is clear and colorful, C/D =0.2~0.3, retinal blood vessels are slender, A/V =2/3, scattered mass pigmentation is seen in the retina of both eyes, accompanied by retinoschisis, macular edema in both eyes, and large choroidal blood vessels are visible (Figure 1）。 Results of FFA: The right eye showed obvious retinal atrophy in the middle periphery and large choroidal vessels in the arteriovenous phase (0: 38.67). The posterior pole retina was slightly stained, with hyperfluorescence at the edges, and patchy hyperfluorescence and fluorescence masking in the macular area. In the late stage (8:24.60), it showed tissue staining of the optic papilla, unclear structure of the macular area with tissue staining, partial fading of the large choroidal vessels, unclear contour, and mild tissue staining. In the left eye arteriovenous phase (0:27.45), the large choroidal vessels were clearly visible, the retinal tissue between the upper and lower vascular arches was stained, hyperfluorescence leakage was seen at the edges, and punctate hyperfluorescence was seen in the macular area. In the late stage (8:31.03), it showed mild tissue staining of the optic papilla, unclear structure of the macular area with tissue staining, unclear contour of choroidal blood vessels with mild tissue staining (Figure 2）。 OCT results: Atrophic changes of conus cell layer and RPE layer in macular area of both eyes, accompanied by cystoid edema in macular area and epiretinal macular membrane (Figure 3）。 flash electroretinogram (f-ERG) results showed no waveforms in both rods, cones and maximal response (Figure 4）。 Multifocal electroretinogram (mf-ERG) results: Severe impairment of retinal and macular function at the posterior pole of both eyes (Figure 5）。 Octopus automatic visual field examination results: peripheral visual field defects in both eyes, residual central visual field (Figure 6）。 The results of color Doppler imaging (CDI) examination showed abnormal intrabulbar echoes in both eyes, mild vitreous opacity, and decreased blood flow parameters of central retinal artery and posterior ciliary artery in both eyes. Diagnosis: Goldmann-Favre syndrome.

The patient was a 38-year-old male. Because of the discovery of unknown white object in front of his right eye for 2 weeks, he went to the Department of Ophthalmology of the 474 Hospital of the People's Liberation Army. The patient had undergone binocular LASIK 13 years ago, and the postoperative visual acuity of both eyes was 1.2. Two years ago, the patient had suffered trauma in his right eye, and the eyes were red, painful, and tearing for 2 days after the injury. After self-administering eye fluid, it improved, and he did not go to the hospital. Eye examination: naked eye vision was 0.5+ in the right eye and 0.5+ in the left eye; Corrected visual acuity was-0.50 DS in the right eye-2.50 DC ×70° =0.6, -1.75 DS for left eye-0.75 DC x 165° =0.9+; Subflap epithelial implantation in the right eye (Quintessence Picture 1）； No abnormalities were observed in the anterior segment and fundus of both eyes. Clinical diagnosis: after LASIK in both eyes; Epithelial implantation under the flap of the right cornea.

The patient was a 71-year-old female. Because of foreign body sensation in his right eye for 3 months, he went to Changchun Aier Eye Hospital. More than 20 years after anti-glaucoma surgery in the right eye. Eye examination: visual acuity was 50 cm index in the right eye and 0.4 in the left eye; IOP was 10 mmHg (1 mmHg =0.133 kPa) in the right eye and 21 mmHg in the left eye. The conjunctiva of the right eyeball is congested, the upper bulbar conjunctival filter vesicle is flat and raised, pale in color, and a round translucent cyst, about 5 mm in diameter, can be seen above the cornea, with posterior iris adhesion, and a root incision can be seen in the iris (Quintessence Picture 1）。 Clinical diagnosis: cystoid follicles after anti-glaucoma surgery in the right eye.

Since sixty percent of ametropes obtain astigmatism, which has influence on the visual quality, correcting the astigmatism is always the focus of concerns during visual correction procedures especially for the corneal refractive surgery. The postoperative spherical equivalent or residual cylindrical dioptors was used as quantitative index to evaluate the correction of astigmatism previously; however, such results neglect the effect of astigmatic axis shift on the treatment. Taking astigmatism as a vector parameter could describe the magnitude and direction of astigmatism accurately, thus it was increasingly applied in the evaluation of astigmatism correction. This paper reviews the present vector analysis methods, evaluation indexes and its application for the correction of astigmatism in the corneal refractive surgery. (Chin J Ophthalmol, 2016, 52:63-67)

Femtosecond small incision lenticule extraction (SMILE) had been performed in clinic more than 5 years in China. With the gradual development of the technology, SMILE has caused more and more attention because of the remarkable clinical effect, micro incision, minimally invasive and refractive stability. The reuse of the refractive lenticule (RL) from SMILE has recently become extensive focus, which brings potential method to corneal refractive surgery from subtraction to addition. This review has clarified the technology of SMILE on the aspects of corneal refractive correct, the clinical effect of reuse the materials (RL), the basis of related research and the possible improvement in the future. (Chin J Ophthalmol, 2016, 52: 68-72)

As an influencing factor of visual quality, straylight is a functional measure of the effect of light scatter across the retina. The phenomenon depends on the refractive index and the turbidity of the ocular media. This light scattering reduces the contrast of the image projected on the retina, and thus decreases the quality of vision. The review focuses on the concept and classification of straylight, and the relationship between straylight and visual quality. (Chin J Ophthalmol, 2016, 52:73-76)