Early changes to dry eye and ocular surface after small-incision lenticule extraction for myopia.

AIM: To investigate the early changes in dry eye symptoms, tear function and ocular surface following small-incision lenticule extraction (SMILE) for myopia. METHODS: Ninety-seven consecutive patients (193 eyes) who underwent SMILE for myopia were observed in this longitudinal and retrospective study. Parameters evaluated included: subjective dry eye symptoms (dryness, foreign body sensation and photophobia), tear film breakup time (TBUT), Schirmer I test (S I T) without anesthesia, tear meniscus height (TMH) and corneal fluorescein staining. Each parameter was evaluated before, and subsequently at 1d, 1wk, 1 and 3mo after surgery. RESULTS: Compared with preoperative data, dryness was noted to be significantly increased at 1wk and 1mo postoperatively (P<0.01). Symptoms of photophobia and foreign body sensation demonstrated significant differences at 1d and 1wk as compared with preoperative scores respectively (P<0.01). These values were decreased at 1 and 3mo post-surgery (P>0.05). Conversely the corneal staining scores were higher than the preoperative data at 1d, 1wk and 1mo (P<0.01), but were close to the preoperative level at 3mo postoperatively. There was a significant decrease in TMH at 1wk and 1mo (P<0.01), but the value was close to the preoperative level at 3mo postoperatively (P=0.16). The examination outcomes of S I T were significantly increased at 1d then reduced at 1wk after surgery (P<0.01). Each value subsequently returned to the baseline value at 1 and 3mo (P>0.05). TBUT was significantly decreased at all postoperative time points (P<0.01). CONCLUSION: SMILE resulted in mild dry eye symptoms, tear film instability and ocular surface damages; however, these complications can recover in a short period of time.

[Clinical evaluation of laser in situ keratomileusis operation with three different ablative patterns].

OBJECTIVE: To evaluate the clinical outcome among three different laser in situ keratomileusis (LASIK) ablations: Q-factor customized ablation (aberration smart ablation, ASA), wave-front guided ablation (WASCA) and ablation under wave-front guiding plus iris recognition system (IR+WASCA). METHODS: This prospective study comprised 96 eyes of 96 patients, and they were randomly divided into three groups: 30 patients in ASA group, 32 in WASCA group, and 34 in IR+WASCA group. There were no any statistical differences in spherical equivalent (SE), age, sex, pupil diameter, higher-order aberrations (HOA) among three groups preoperatively. Wave-front analysis was performed before and 1, 3 months after operation. RESULT: All patients got an uncorrected visual acuity (UCVA) ≥ 0.8 1 and 3 months after operation. The residual SE was in ± 0.50D both at 1 and 3 months after surgery. There was no statistical difference in SE value, HOA, change of HOA, and coma aberration postoperatively among three groups. Horizontal coma (Z3¹) aberration took the majority of coma. HOA, total coma aberrations and spherical aberration increased postoperatively (P = 0.000), but without significant difference between 1 month and 3 months after surgery. CONCLUSION: That three customized LASIK are all effective, safe, accurate and stable; meanwhile WASCA may have better UCVA than the other two groups postoperatively.

[Present status of genome-wide association studies and its applications in ophthalmology].

Genome-wide association studies (GWAS) assay a dense set of single-nucleotide polymorphisms (SNPs) in whole genome and relate them to various diseases and measurable traits. The completion of Human Genome Project and Human Haplotype Map Project has made this approach possible. Genome-wide association studies have identified a large number of robust associations between genetic variants and common diseases. Now, application of GWAS in eye diseases are actively being pursued and these studies provide an effective methodology for studying the genetic aspects of ophthalmic complex diseases. In this paper, we describe the current understanding of concept, background, development, advantages and disadvantages of GWAS, as well as applications of GWAS in the field of ophthalmology.

[The autonomic pupillary dysfunction in type II diabetes mellitus].

OBJECTIVE: To evaluate the pupillary disorder associated with autonomic neuropathy of type II diabetes mellitus by investigating pupil diameters under mesopic, photopic and pharmacologically dilated conditions. METHODS: Forty of type II diabetic patients were divided into two groups based on the results of fundus fluorescein angiography, one group was the subclinic diabetic retinopathy and another was the NPDR (nonproliferative diabetic retinopathy), 20 age-matched healthy subjects were selected as control. High-resolution images of the pupil in 60 subjects were taken using an infrared-sensitive camera under mesopic, photopic and pharmacologically dilated conditions, respectively. From the images, the pupil diameters, constriction ratio and dilatation ratio were analyzed using Photoshop, Acdsee, and Imagetools software. RESULTS: The mean pupil diameter of tested subjects in mesopic control, subclinic and the NPDR were (6.02 +/- 0.48), (5.87 +/- 0.99), (4.95 +/- 1.12)mm, respectively. The mean photopic pupil diameter in three groups were (3.40 +/- 0.33), (3.37 +/- 0.31), (3.25 +/- 0.47) mm, respectively, where the mean pharmacologically dilated pupil diameter in three groups were (7.37 +/- 0.59), (6.91 +/- 1.00), (5.49 +/- 1.24) mm, respectively. The mean constriction ratio of these three groups were (43 +/- 7)%, (41 +/- 10)%, (32 +/- 14)%, respectively. The mean dilatation ratio of these three groups were (23 +/- 8)%, (19 +/- 13)%, (11 +/- 5)%, respectively. There were statistically significant differences among three groups in dark adapted pupil diameter, dilated pupil diameter, constriction ratio and dilatation ratio (P < 0.05). CONCLUSIONS: Autonomic pupillary dysfunction occurs early in type II diabetic patients. Pupillary diameters under mesopic and pharmacologically dilated conditions, and other pupil changes such as constriction ratio and dilatation ratio can be the reliable sign to evaluate autonomic neuropathy of type II diabetes mellitus.

Bilateral comparison of conventional versus topographic-guided customized ablation for myopic LASIK with the NIDEK EC-5000.

PURPOSE: To compare visual acuity and higher order aberrations before and after myopic LASIK using conventional versus customized ablation. METHODS: This prospective, randomized study included 54 myopic eyes in 27 patients who underwent bilateral LASIK using the NIDEK EC-5000 excimer laser system (NIDEK Technologies, Gamagori, Japan). Customized aspheric treatment zone (CATz) treatment was used in one eye (CATz group) and conventional ablation (conventional group) was used in the fellow eye. Uncorrected visual acuity (UCVA) and higher order aberrations (root-mean-square [RMS] in 4-mm and 6-mm zones) of both groups were observed with the NIDEK OPD-Scan aberrometer before and 3 months after LASIK. Preoperative mean refractive error was similar for both eyes of each patient (P>.05). RESULTS: No statistically significant differences were noted in preoperative higher order aberrations (RMS in 4-mm and 6-mm zones) between groups (P>.05). No statistically significant difference was noted between pre- and postoperative higher order aberrations in the CATz group (P>.05). However, a highly statistically significant increase in higher order aberrations was observed after conventional ablation (P<.001). There was a statistically significant higher increase of higher order aberrations after LASIK in the conventional group than the CATz group (P<.05). Postoperative UCVA with both conventional and customized ablation was not significantly different (P>.05). CONCLUSIONS: LASIK with conventional ablation and CATz ablation resulted in the same UCVA. The increase in higher order aberrations after CATz ablation was less than after conventional ablation.