Chinese Journal of Optometry Ophthalmology and Visual science

Small incision lenticule extraction (SMILE) surgery is a brand-new concept and treatment that uses excimer laser for refractive corneal surface or stromal ablation. To obtain a satisfactory outcome and provide comfort for the majority of the patients with ametropia, it is particularly important to understand and correctly apply the operational mode of the laser. To provide references for SMILE surgery clinical safety implementation and steady development, this article interprets the consensus of SMILE surgery outcomes obtained in clinical practice and further explores the connotation and clinical significance of the practical applications of this new surgical modality.

Objective To understand the clinical features and electrophysiological characteristics of familial nanophthalmos. Methods Pedigree clinical research was performed on a family with nanophthalmos. Detailed ocular examinations including visual acuity, fundus ophthalmoscopy, axial length, optical coherence tomography (OCT), pattern visual evoked potential (PVEP), pattern electroretinogram (PERG), and full-field ERG were obtained for each of the family members. Results Three consecutive generations, including five affected subjects were confirmed in this family. Affected subjects occurred in all three consecutive generations, and father to son transmission occurred, which was consistent with autosomal dominant inheritance. The best corrected visual acuity of five patients was lower than 0.8 LogMAR, and axial length of three patients ranged from 17.27 to 18.85 mm with shortening of the anterior chamber and the vitreous cavity. Three patients had a small crowded optic disc, and one had a normal fundus. OCT examination showed normal retinal morphology but increased foveal thickness (>280 µm). Visual electrophysiological tests revealed normal P100 latency and amplitude in the affected subjects. The PERG was normal but both a- and b- wave amplitudes were significantly higher than the age matched normal subjects for full-field ERG. Conclusion The nanophthalmos condition can be inherited in an autosomal dominant pattern. The presenting visual acuity was less than normal for all patients, and the foveal thickness was increased with a supernormal full-field ERG response.

Objective To investigate difference of retinal light sensitivity between high myopia subjects and low myopia to emmetropia subjects in the macular areas. Methods This descriptive study enrolled subjects from the Department of Optometry, Eye Hospital of Wenzhou Medical University, and campus volunteers, from November 2015 to May 2016. Clinical data were recorded and the subjects were divided into a high myopia group with 31 cases (31 eyes) and a control group with 30 cases (30 eyes). Retinal light sensitivity was measured in the central 20° of the macula using a microperimeter. The macular area covered by the microperimeter was divided into three rings, including central, inner, and outer rings. The rings were further divided into nine areas (A1-A9). Data in each area were compared by independent t-test between the two groups. The relationship between retinal light sensitivity and axial length was assessed by Pearson correlation analysis. Results The average retinal light sensitivity of the macula was reduced in the high myopia group compared to the control group (t=4.60, P＜0.001). In the inner and outer rings, the retinal light sensitivity of the high myopia group was reduced (t=3.30, P=0.002; t=3.63, P=0.001 respectively). For all three rings, the sensitivity was reduced in A2 (t=2.02, P=0.047), A4 (t=3.68, P=0.001), A5 (t=3.05, P=0.004), A6 (t=2.17, P=0.034), A7 (t=2.49, P=0.016), A8 (t=3.40, P=0.002), and A9 (t=4.35, P＜0.001). Retinal sensitivity was inversely correlated with the axial length (r=-0.477, P＜0.001). Conclusion Retinal sensitivity of the macular area was reduced in high myopia subjects with normal corrected visual acuity. The decreased sensitivity was more obvious in the outer ring and was correlated with increased axial length.

Objective To determine if retinal oxygen metabolism is different in glaucoma patients compared to healthy subjects and to determine if retinal vessel oxygen saturation is correlated with structural and functional damage in glaucoma patients. Methods This case control study included 28 patients (35 eyes) with primary open-angle glaucoma and 27 healthy individuals(41 eyes). Visual fields were measured with a Humphrey field analyzer. Optical coherence tomography (OCT) was performed to detect the thickness of the retinal nerve fiber layer (RNFL) in glaucoma patients. Retinal vessel oxygen saturation was measured in glaucoma patients and healthy individuals with a non-invasive spectrophotometric retinal oximeter. Statistical analysis was performed using independent t-test and Pearson′s correlation. Results There was no significant difference in retinal arteriole oxygen saturation between glaucoma patients and healthy individuals. However, the oxygen saturation in venules was higher and the arteriovenous difference was lower in glaucoma patients (t=4.017, P＜0.001; t=-4.431, P＜0.001). Retinal arteriolar oxygen saturation was not associated with age, intraocular pressure, blood pressure, cup-to-disc ratio, mean deviation (MD), visual field index (VFI), or RNFL thickness in glaucoma patients. The retinal oxygen saturation in both the venules and arteriovenous (AV) difference was not correlated with age, intraocular pressure, or blood pressure in glaucoma patients. Retinal venous oxygen saturation was positively correlated with the cup-to-disc ratio (r=0.418, P=0.012) and MD (r=0.504, P=0.002) and negatively correlated with RNFL thickness (r=-0.514, P=0.002) and VFI (r=-0.470, P=0.004) in glaucoma patients. On the other hand, the AV difference was negatively correlated with the cup-to-disc ratio (r=-0.390, P=0.021) and MD (r=-0.478, P=0.004) and positively correlated with RNFL thickness (r=0.385, P=0.022) and VFI (r=0.449, P=0.007) in glaucoma patients. Conclusion Severe glaucomatous damage is associated with increased oxygen saturation in venules and a decrease in the AV difference in retinal oxygen saturation, suggesting that reduced retinal oxygen consumption is related to the atrophy of the retinal nerve fibers.

Objective To investigate changes in corrected visual acuity (CVA) and refractive error after strabismus surgery. Methods Four groups of patients (n=133, 194 eyes) undergoing strabismus surgery at Beijing Tongren Hospital from December 16, 2013 to August 13, 2014 participated in this prospective study. Group 1 had one rectus recession (n=63, 102 eyes); Group 2 had one rectus recession combined with rectus resection on the antagonistic muscle (n=19, 27 eyes); Group 3 had one rectus recession combined with improved rectus linear tucking on the antagonistic muscle (n=40, 50 eyes); and Group 4 had one rectus recession combined with one oblique recession (n=11, 15 eyes). A two-way repeated measures ANOVA was used to examine the CVA and refractive error before surgery and at 1, 3, and 6 months after surgery. The amount and type of astigmatism were compared by chi-square test. Results There were no significant differences in preoperative CVA, spherical equivalent (SE), or astigmatism among the four groups. There were no significant differences in group, time, or interaction of CVA and SE. There were no significant differences in groups or in interactions, but there were significant differences in the groups at different time points (F=30.50, P＜0.001). The astigmatism increased at one and three months in all groups compared to preoperative levels (P＜0.05) but decreased 6 months after surgery compared to levels at one and three months postoperatively. The astigmatism ratios preoperatively and at 1, 3, and 6 months postoperatively were 57%, 73%, 76%, and 62%, respectively. The ratio of astigmatism increased at one and three months after surgery (χ²=20.29, 19.80, P＜0.001), but there were no significant differences between the preoperative and the 6 months postoperative values. Conclusion CVA changes can be expected in the short term after strabismus surgery, especially increasing astigmatism. However, the refractive status can recover to preoperative levels over time．There were no significant variations between different surgical methods．

Objective To examine the changes in lens parameters in pre-school myopic children with a history of retinopathy of prematurity (ROP) and to identify the relationship between lens parameters and myopia with ROP. Methods In this cases control study, 66 children (126 eyes) aged 1 to 6 years were recruited from the Department of Ophthalmology in Hunan Children's Hospital from January 2014 to December 2015. ROP surgical patients were excluded. They were divided into the following two groups based on gestational age, history of ROP, and refractive status: (1)myopia with a history of ROP (36 cases, 68 eyes, MOR group) and (2) no myopia with ROP (30 cases, 58 eyes, Non-MOR group). Differences in optical parameters and lens thickness variation before and after cycloplegia were compared. Data between two groups were compared by t-test. Results For children aged 1-3 years, the MOR group had a steeper corneal curvature (t=2.916, P＜0.01) and greater lens thickness (LT) (t=3.227, P＜0.01) than did the non-MOR group. For children aged 4-6 years, only the LT of the MOR group was thicker (t=2.257, P＜0.05). The MOR group had a thicker LT before cycloplegia (t=3.152, P＜0.01) and less lens thickness variation before and after cycloplegia (t=2.045, P＜0.05) compared to the non-MOR group. Conclusion (1)In pre-school children, ROP myopia derives mainly from the increase in lens power. (2)Myopic children with ROP have a thicker lens. The change in the LT before and after mydriasis is small, suggesting that ROP may affect the elasticity and regulation of the lens. (3)The adjustment function of the lens and the matching optical components may be one of the important factors in the myopia of ROP.

Objective To investigate the distribution of refractive state in children aged 3 to 6 years old with subnormal vision and to analyze the relationship between different refractive types and amblyopia. Methods This was a descriptive study of 674 children (1 348 eyes) aged 3 to 6 years old who had subnormal vision (3 years old≤20/40, 4 years old≤20/32, 5-6 years old≤20/25). Refraction and corrected visual acuity were detected after cycloplegia using 1% atropine ointment. The distribution of refractive errors in cases with and without amblyopia were analyzed. The incidence of anisometropia at different ages and the relationship between anisometropia and amblyopia were studied. The distribution of refractive errors and the incidence of amblyopia were compared by the chi-square test. Results The majority of the children were hyperopic, and myopia rarely occurred. With increasing age, the proportion of children with hyperopia decreased gradually while myopia increased, and the difference was statistically significant (χ²=99.7, P＜0.001). There was a significant difference in the distribution of refraction between amblyopic and non-amblyopic eyes (χ²=20.1, P=0.01). The first three refractive causes of amblyopia were compound hyperopic astigmatism (59.4%), simple hyperopia astigmatism (17.8%), and mixed astigmatism (15.8%). No amblyopia occurred in the eyes with simple myopia. The incidence of amblyopia was higher when the spherical equivalent difference between the two eyes was or more than 1 diopter. There was a significant increase in the occurrence of amblyopia with increased anisometropia (χ²=62.9, P＜0.001). Conclusion The majority of children 3 to 6 years old with subnormal vision have hyperopia. Hyperopia, astigmatism, and anisometropia are prone to cause amblyopia.

Objective To compare the effect of atropine drug penalization and patching therapies of children with anisometropic amblyopia or strabismus amblyopia. Methods In this prospective clinical study, children and adolescents diagnosed with anisometropic amblyopia or strabismus amblyopia who had complete clinical data of more than 12 months were recruited from January 2013 to March 2015. They were divided into an atropine penalization group and patching group. And patients were further divided into mild, moderate, severe degree to analyze. The degree of amblyopia for the two groups was compared with the Wilcoxon rank sum test. The effective rate and cure rate for the two groups were compared by chi-square tests. Results A total of 85 patients (85 eyes) with anisometropic or strabismus amblyopia were recruited and divided into a patching group of 52 patients (52 eyes) and an atropine penalization group of 33 patients (33 eyes). The cure rates were 60% and 64% in the patching and penalization groups respectively (χ²=0.137, P=0.711). The effective rates were 88% and 85% for the patching and penalization groups respectively (χ²=0.234, P=0.629). There was also no significant difference between the two groups when the rates of effectiveness for different degrees of amblyopia were compared. Fifty-two eyes in the patching group and 29 eyes in the penalization group developed a fixating eye after 3-6 months of treatment, but 4 eyes in the penalization group did not develop a fixating eye. Conclusion Atropine drug penalization therapy has a similar effect on anisometropic or strabismus amblyopia in children as does traditional patching therapy.

Objective To summarize the clinical features of intraorbital foreign bodies and the surgical management. Methods Retrospective study of 22 clinical cases. Clinical manifestations, image findings, and surgical treatment of patients with intraorbital foreign bodies diognosed and treated in the Zhongshan Ophthalmic Center between January 2002 and July 2013 were reviewed. Results Of the patients, 19 were males and 3 were females with ages from 3 to 67 years. Patients with ≤14 years of age accounted for 46% of the cases. The right orbit was affected in 10 cases and the left one in 12 cases. Of the cases, 73% had an organic intraorbital foreign body. The sites of the foreign bodies within the orbit were superior (41%), medial (27%), lateral (18%), inferior (9%), and muscle cone posterior segment (4%). Half of the subjects presented with preoperative visual impairment, and 46% with preoperative limited motility/strabismus and ptosis. Orbital computed tomography scans showed that the organic foreign bodies appeared as rod-like strips with high density compared to the surrounding soft tissue. Magnetic resonance imaging revealed hypointense images on both T1WI and T2WI. The intraorbital foreign bodies were completely removed by anterior orbitotomy in 21 cases and by lateral orbitotomy in one case. Among them, 21 cases underwent a single operation and one case had two operations. Only two patients had temporary mild postoperative ptosis. Conclusion Intraorbital foreign bodies usually occurred in male children. Orbital imaging played an important role in accurate presurgical diagnoses. Anterior orbitotomy usually resulted in a satisfactory surgical outcome.