Surgical induced astigmatism correlated with corneal pachymetry and intraocular pressure: transconjunctival sutureless 23-gauge versus 20-gauge sutured vitrectomy in diabetes mellitus.

AIM: To determine the difference of surgical induced astigmatism between conventional 20-gauge sutured vitrectomy and 23-gauge transconjunctival sutureless vitrectomy, and the influence of corneal pachymetry and intraocular pressure (IOP) on surgical induced astigmatism in diabetic patients. METHODS: This retrospective, consecutive case series consisted of 40 eyes of 38 diabetic subjects who underwent either 20-gauge or 23-gauge vitrectomy. The corneal curvature and thickness were measured with Scheimpflug imaging before surgery and 1wk; 1, 3mo after surgery. We compared the surgical induced astigmatism (SIA) on the true net power in 23-gauge group with that in 20-gauge group. We determined the correlation between corneal thickness change ratio, IOP and SIA measured by Pentacam. RESULTS: The mean SIAs were 1.082±0.085 D (mean±SEM), 0.689±0.070 D and 0.459±0.063 D at postoperative 1wk; 1, 3mo respectively in diabetic subjects. The vitrectomy induced astigmatisms were declined significantly with time (F 2,36=33.629, P=0.000) postoperatively. The 23-gauge surgery group induced significantly less astigmatism than 20-gauge surgery group (F -1,37=11.046, P=0.020). Corneal thickness in diabetes elevated after surgery (F 3,78=10.532, P=0.000). The linear regression analysis at postoperatively 1wk went as: SIA=-4.519+4.931 change ratio (Port3) +0.026 IOP (R(2)=0.46, P=0.000), whereas the rate of corneal thickness change and IOP showed no correlation with the change of astigmatism at postoperatively 1 and 3mo. CONCLUSION: There are significant serial changes in both 20-gauge and 23-gauge group in diabetic subjects. 23-gauge induce less astigmatism than 20-gauge and become stable more rapidly than 20-gauge. The elevation of corneal thickness and IOP was associated with increased astigmatim at the early postoperative stage both in 23-gauge and 20-gauge surgery group.

[Pathogenic mechanisms and therapeutic strategies of myopic traction maculopathy].

Myopic traction maculopathy is a group of ocular fundus diseases related to high myopia, which can severely impact on patients' visual function. It is well recognized that the abnormal of macular structure and function in the disease are resulted from various traction mechanisms, including the forces from posterior vitreous detachment, posterior vitreous cortex, and macular epiretinal membrane which acting on the inner retina, the force from posterior staphyloma which acting on the outer retina, and retinal intrinsic features such as the changes of inner limiting membrane and arterioles. The treatments are mainly based on surgery, including vitrectomy and scleral reinforcement surgery in order to relieve the retinal traction. The options of specific surgery procedures are still under debated. In this article, we reviewed the pathogenic mechanisms and therapeutic strategies of myopic traction maculopathy.

[Coverage on cataract surgery among adults aged 40 or above in a multiethnic rural district of high altitude area in Gongshan county, Yunnan province, China].

OBJECTIVE: To estimate the prevalence of cataract and its surgical coverage rate together with the burden related to bilateral cataract-blindness, among adults aged 40 or above in Gongshan county of Yunnan province and to evaluate the current cataract status and the efficacy of local cataract prevention program. METHODS: Cluster sampling was used. The protocol consisted of personal interview, pilot study, visual acuity checking, measuring the intraocular pressure; slit lamp microscopy and the fundus of the eye examination etc. Cataract was graded clinically using the Lens Opacity Classification System (LOCS) III. Bilateral cataract-blindness burden, bilateral cataract-blindness burden and cataract surgical coverage rate were calculated respectively, using two different criteria. Odds ratios (OR) were compared among different groups regarding age, gender, education, ethnic group and altitude of living area. RESULTS: Among the 1236 eligible residents, 1116 (90.3%) were enrolled in the present study. The prevalence of cataract was 23.8% among adults aged 40 or order. When the bilateral best refractive vision<3/60 was defined as the blindness criterion, the bilateral cataract-blindness burden showed as 1.3%, and cataract blindness surgical coverage rate was 50.0%. When the bilateral presenting vision<6/60 was defined as the blindness criterion, the bilateral cataract-blindness burden was 25.0%, and cataract blindness surgical coverage rate was 12.9%. The cataract surgical coverage rates were much lower and the bilateral cataract-blindness burden much higher in women, illiterates, living in high altitude areas and those who were aged 70 or above. CONCLUSION: Cataract blindness was a serious public health problem in aged individuals and illiteracy in the residents of the studied areas. Poor prevention programs on cataract called for urgent action to be taken.

[Prevalence survey of visual impairment in a multiethnic rural district in the high altitude area of Yunnan Province, China].

OBJECTIVE: To estimate the prevalence and causes of visual impairment by a population-based survey conducted in Gongshan County of Yunnan Province. METHODS: Cluster sampling method was used for sample selection. In person interview, pilot study, visual acuity (VA) check, intraocular pressure, slit lamp microscopy and fundus examination were performed. The diagnoses of blindness (VA<0.05) and visual impairment (VA<0.3 to ≥0.05) were based on best-corrected visual acuity in the better eye. The prevalence of visual impairment was calculated as to age, gender, education, ethnic group and altitude of living area. The dominant causes of blindness and visual impairment were then identified. The comparison of prevalence among different group examined by four-fold table Chi-square test, R×2 Chi-square test and trend Chi-square test. RESULTS: Among 3070 eligible residents, 2460 (80.1%) were finally enrolled in the present study. The total prevalence of visual impairment was 6.46%. The bilateral blindness and unilateral blindness was 19 and 46 respectively. The bilateral and unilateral low vision was 49 and 45 respectively. There was no statistical significant difference of prevalence of visual impairment among different ethnic groups (χ2=0.75, P=0.388). There was significantly statistical difference of prevalence of visual impairment among groups who lives in different altitude area (χ2=18.34, P=0.000). High prevalence were also observed in the elder (≥70 years), illiterate and outdoor-workers, which was 2.24%, 4.19%, 5.65% respectively. The leading causes of bilateral blindness was cataract (42.1%, 8/19), corneal opacity (26.3%, 5/19), and retinal abnormality (21.1%, 4/19). The leading cause of bilateral low vision was also cataract (42.9%, 21/49). CONCLUSIONS: Cataract was the dominant cause of visual impairment in Gongshan County of Yunnan Province. The study highlights an urgent need of visual impairment prevention program conducted by local public heath intervention, especially focusing on cataract treatment.