Observation and study on uncorrected distance visual acuity and ocular adjustment function before and after excimer laser photorefractive keratectomy / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To analyze the changes of uncorrected distance visual acuity(UCDVA)and ocular accommodation before and after excimer laser photorefractive keratectomy(PRK).METHODS: A retrospective study. There were 120 patients(240 eyes)who underwent PRK surgery in our center from December 2017 to December 2019 divided into two groups according to the diopter of spherical equivalent(SE): 70 cases with SE≤-6.00D in the mild to moderate myopia group and 50 cases with -6.00D<SE≤-9.00D in the high myopia group which were observed and analyzed. The UCDVA(LogMAR), monocular accommodative amplitude(AMP), negative relative accommodation(NRA), positive relative accommodation(PRA)and monocular accommodative flipper(AF)were measured before and after operation at 1wk, 1 and 3mo. RESULTS: In the group of low-moderate myopia and high-myopia group, the UCDVA at 1wk, 1 and 3 mo after operation was significantly increased compared with those before operation(all P<0.01). The increase of UCDVA of low to moderate myopia group was better than that in the high myopia group at 3mo after operation(P<0.05). Monocular AMP in the both groups firstly decreased and increased afterwards, and there was a significant decrease than that before operation at 1wk and 1mo after operation(P<0.01). AMP reached and was better than that before operation at 3mo after operation(P<0.01). The increase of low to moderate myopia group was both higher and faster than that of high myopia group. Compared with PRA before operation, the patients of low to moderate myopia group decreased at 1wk after operation(P<0.01), postoperative levels at 1mo recovered to preoperative level(P>0.05)and postoperative at 3mo was superior to preoperative operation(P<0.05); High myopia group did not change significantly at 1wk and 1mo after operation compared with preoperative operation(P>0.05), and increased at 3mo after operation compared with preoperative level(P<0.01). For low to moderate myopia group, there was no significant difference in preoperative and postoperative NRA, and at 1wk after operation, NRA of high myopia group temporarily increased compared with preoperative operation(P<0.01). At 1mo after operation, it returned to the preoperative level(P>0.05), and significantly increased at 3mo after operation compared with preoperative operation(P<0.01). Monocular AF for both groups significantly decreased at 1wk after operation compared with preoperative operation, recovered at 1mo after operation and was significantly better at 3mo after operation(all P<0.01); The low-to-moderate group increased more than the high-myopia group.CONCLUSION: PRK has a good correction effect for myopia below -9.00D, and people in low to moderate myopia have a better postoperative UCDVA correction effect than those in high myopia. The eye accommodation will be abnormal in a short period after operation. The recovery and improvement time of accommodative function in low-moderate myopia group are shorter than that in high myopia group, but both groups can recover and improve at 3mo after operation compared with the preoperative levels.

Relationship between the structural and functional changes of macular and HbA1c after cataract surgery in diabetic patients / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To explore the relationship between HbA1c and the changes of retinal and choroidal structures in macular region, and between HbA1c and corrected distant visual acuity before and after cataract surgery in diabetic patients.<p>METHODS: It is a prospective randomized clinical trial. According to the patient's history, the subjects were divided into the non-diabetes group and the diabetic group. According to the level of HbA1c before operation, the diabetic group was divided into the high HbA1c group(HbA1c>7.0%)and the normal HbA1c group(HbA1c≤7.0%). All 87 eyes from 82 patients who met the criteria from October 2016 to December 2017 in the Department of Ophthalmology at Qingdao Municipal Hospital were enrolled in this study. There were 30 eyes from 28 patients in the non-diabetes group(4%≤HbA1c≤6.0%), 29 eyes from 28 patients in the high HbA1c group and 28 eyes from 26 patients in the normal HbA1c group. Spectral-domain optical coherence tomography(SD-OCT)was used to examine central subifield thickness(CST), central volume(CV)and subfoveal choroidal thickness(SFCT)at 1d before surgery, 1d after surgery, 1wk after surgery, 1mo after surgery and 3mo after surgery. The variance analysis and Pearson correlation analysis were used to analyze the changes and the correlation with HbA1c value. At the same time, the incidence of macular edema after surgery(PCME)was compared among the groups, and the relationship between HbA1c and postoperative corrected distance visual acuity(CDVA)in diabetes patients was also analyzed. <p>RESULTS: In non diabetic group, high HbA1c group and normal HbA1c group, CST was 239.03+11.55μm, 254.38+26.44μm, 247.07+19.51μm at 1wk after cataract surgery. Their CST was 241.00±11.15μm, 271.55±61.05μm, 248.64±38.28μm at 1mo after cataract surgery(<i>F</i>=3.001, <i>P</i>=0.048). Besides, there was a positive correlation between HbA1c and CST at 1wk and 1mo after operation in the two groups at <i>P</i>=0.01 level(<i>r</i>1wk=0.338, <i>r</i>1mo=0.297)(<i>P</i><0.05). The postoperative macular cystoid edema in non-diabetic group, high HbA1c group and normal HbA1c group were 0, 5(5 eyes, 17%)and 1(1 eye, 4%)respectively. In non diabetic group, high HbA1c group and normal HbA1c group, CDVA was 0.07±0.06, 0.12±0.10, 0.09±0.08 at 1wk after cataract surgery. Their CDVA was 0.03±0.06, 0.11±0.15, 0.11±0.09 at 1mo after cataract surgery. Their CDVA was 0.02±0.04, 0.08±0.12, 0.06±0.06 at 3mo after cataract surgery(<i>F</i>=3.272, <i>P</i>=0.045). The differences among three groups in the CDVA were statistically significant at 1wk, 1mo and 3mo after surgery. There was no significant difference between the high HbA1c group and the normal HbA1c group(<i>P</i>>0.05). However, CDVA(LogMAR)of the two groups was positively correlated with HbA1c at <i>P</i>=0.01 level(<i>r</i>1wk=0.425, <i>r</i>1mo=0.235, <i>r</i>3mo=0.332). There was no statistically significant difference in the changes of CV and SFCT among the three groups, and the trend of changes among these groups was approximately the same. <p>CONCLUSION: There is a close relationship between the microscopic structure of macula and HbA1c before phacoemulsification in diabetic patients. The risk of macular edema increased in patients with hba1c >7.0% before surgery. The best corrected visual acuity of diabetes patients after surgery was significantly related to the hba1c value before surgery. The higher the hba1c value before surgery, the poorer the improvement of vision after surgery. The level of HbA1c before surgery in diabetic patients is related to the anatomical structure of macular after cataract surgery. The risk of macular edema after surgery is increased in patients with high HbA1c(HbA1c>7.0%)before surgery. Meanwhile, the preoperative HbA1c of diabetic patients is closely related to CDVA after cataract surgery. The higher the preoperative HbA1c value, the worse the CDVA in diabetics after surgery.

Vision distribution and its influencing factors of two teenager aviation schools in Western China / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To analyze the vision distribution and its related risk factors of two teenager aviation schools in Western China. <p>METHODS: The study was a cross-sectional survey. A total of 233 participants were randomly selected from two teenager aviation schools in Western China in November and December of 2017, which were all qualified through the standard of physical examination by Air Force. Distance visual acuity of students was checked and questionnaires about influencing factors of vision were filled voluntarily. Mann-Whitney <i>U</i> rank-sum test and chi-square test were applied for single factor analysis, and Multiple factor Logistic regression analysis was used for the main influence factors of the vision difference. <p>RESULTS: The proportion of students with less than 0.8 eyesight in school B of Grade 2 and Grade 3 were 18.6% and 45.9%, which was significantly higher than that of 2.6% and 20% of school A. The well-vision distribution in school B of Grade 2 and Grade 3 were lower than that of school A(<i>P</i><0.05). Single factor analysis showed that school reading and writing time in school B of Grade 2(360min, average: 180-535min)and Grade 3(470min, average: 440-500min)were higher than that of school A(Greade 2: 200min, average: 180-315min; Grade 3: 440min, average: 400-480min; <i>P</i><0.05); and outdoor activity time of the two grades(Grade 2: 420min, average: 325-516min and Grade 3: 378min, average: 265-515min)were lower than that of school A(Grade 2: 510min, average: 439-681min and Grade 3: 440min, average: 370-601min; <i>P</i><0.05), and the proportion of students whose mother had a senior high school degree or above in school B was lower than that of school A(<i>P</i>=0.032). Multiple factor Logistic regression analysis showed that reading and writing time was a risk factor for vision loss(<i>OR</i>=1.109, <i>P</i>=0.010)and outdoor activity time was a protective factor(<i>OR</i>=0.986, <i>P</i>=0.001). Mothers' education background, father's educational background, parents' myopia, primary school enrollment age, class time and electronic product using time were not the main factors affecting the vision. <p>CONCLUSION: More reading and writing time and less outdoor activity time are the main factors for loss of vision, the key point of school myopia prevention needs to coordinate the time between reading, writing and outdoor activity.

Comparison of Improvement Rates between Distance and Near Visual Acuity in Children with Unilateral Amblyopia

PURPOSE: To compare the improvement rates of distance visual acuity (VA) with that of near VA in amblyopic eyes of children with unilateral amblyopia. METHODS: The medical records of children with unilateral amblyopia successfully treated with patching were reviewed. During subsequent visits for amblyopia treatment, subjects had best-corrected VA measured at 4 meters and 1/3 meters every 2 months. Duration of treatment to achieve equal VA between both eyes and improvement rates were compared between distance and near, and analyzed according to the cause and severity of amblyopia, or age. RESULTS: A total of 76 children with amblyopia due to anisometropia and/or strabismus started amblyopia treatment at a mean age of 5.8 years and were followed up during a mean period of 16.4 months. Baseline VA was better at near than at distance in 52 children (68.4%), and better at distance than at near in 4 (5.3%). The mean duration of treatment was 5.4 months at distance and 3.9 months at near. However, the improvement rate considering the amount of improvement of VA was faster at distance; 0.11 log MAR/month at distance, and 0.08 log MAR/month at near (p = 0.016). The improvement rate differences between distance and near did not differ based on the cause of amblyopia, or age, whereas in mild amblyopia the improvement rate of distance VA was significantly faster than near. Additionally, children with better initial near VA tended to have a faster improvement rate of distance VA. CONCLUSIONS: Although baseline VA was better at near than at distance in more patients, the improvement rate was faster at distance than at near. Children with better initial near VA appeared to have a faster improvement rate of distance VA.

Outcomes of Small Incision Lenticule Extraction: Mild to Moderate Myopia versus High Myopia

PURPOSE: To evaluate the refractive outcomes of small incision lenticule extraction (SMILE) in high myopia patients compared with mild to moderate myopia patients. METHODS: This study included 332 eyes of 166 myopic patients treated with SMILE using Visumax 500 kHz femtosecond laser. Treated eyes were divided into 2 groups according to preoperative spherical equivalent (SE): mild to moderate myopia (A group, or =-6.0 D). Follow-up visits were at 1 day, 1 week, 1 month, 3 months, and 6 months. The outcome measures included uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BDVA), postoperative SE, efficacy index, safety index and predictability. RESULTS: Preoperative SE was -4.85 +/- 0.86 D in the A group and -7.70 +/- 1.0 D in the B group. No differences were observed between -0.04 +/- 0.29 D in the A group and -0.30 +/- 0.37 D in the B group at 6 months postoperatively (p = 0.062). At 6 months postoperatively, 98.3% and 97.3% had UDVA of 20/25 or better in the A group and B group, respectively. In the A group, 97.3% and 100% were within +/-0.5 D and +/-1.0 D of intended correction and in the B group, 91.7% and 96.9% were within +/-0.5 D and +/-1.0 D, respectively. Efficacy indices were 1.02 +/- 0.19 in the A group and 0.99 +/- 0.18 in the B group. Safety indices were 1.16 +/- 0.16 in the A group and 1.14 +/- 0.16 in the B group. The efficacy and safety indices were not significantly different between the A and B groups at 6 months postoperatively (p = 0.09, p = 0.695, respectively). CONCLUSIONS: This study showed that SMILE is effective and safe for correcting high myopia as well as mild to moderate myopia.