Expanded understanding of the ocular surface and tear film interaction contributes to the pathophysiology of dry eye.Maintenance of tear film requires an intricate nervous and hormonal regulation.The changes in tear film,neurogenic inflammation and sex hormone are key factors in dry eye pathogenesis.

According to the anatomic classification,refractive surgery is divided into keratorefractive surgery,phakic refractive surgery and scleral refractive surgery.Most procedures for the correction of ametropia are performed on the cornea,with laser-assisted in situ keratomileusis(LASIK) being the most common one.LASIK has shown its limitations,however.For the correction of higher myopic and hyperopic refractive error,the procedure has considerable undesired effects,such as loss of contrast,glare,and iatrogenic keratectasia.Therefore,a variety of intraocular lens,known as phakic refractive surgery,have been designed to achieve full correction of high myopia and hyperopia without loss of accommodation.Phakic refractive surgery is different from kerato-or scleral refractive surgery in that it involves phakic intraocular lens,non-phakic intraocular lens and clear lens extraction +introcular lens.The author will outline recent progress in phakic intraocular lens and provide unifying concepts that are accepted by ophthalmologists.

Keratoconus is a relatively common, bilateral, non-inflammatory corneal ectasia characterized by thinning and scarring of the central portion of the cornea,seriously destroyed the vision. The aetiology of this condition is probably multiple factors,such as collagen themry,genetic themry,epithelia themry,etc.Now,recent investigations devote to gene,and think it one of the major aetiological factors. Laboratory studies suggest a role for degradative enzymes and proteinase inhibitors and a possible role for the interleukin-1 system in its pathogenesis, but these roles need to be more clearly defined. It has well-described clinical signs, but early forms of the disease may go undetected unless the anterior corneal topography is studied. Contact lenses are the most common treatment modality. When contact lenses fail, corneal transplant is the best and most successful surgical option.

corrected visual acuity and good visual quality are clinic effects standard of laser in situ keratomeleusis.Visual quality descending for patients after LASIK surgery depends on many factors.This review recommends analyses the influence of visual quality for patients after LASIK surgery and it's guiding significance to LASIK from seven sides,such as visual acuity,refactive diopter,contrast sensitivity,wavefront aberration,increment of Q-value,binocular visual function,the change of dominant eye.

Recent studies of immunology have aroused new interest in regulatory T cell for immune responses,and scientists have recognized that suppressor T cells exist in vivo and regulatory T(Treg) cells play a crucial role in mediating immune tolerance and preventing autoimmune diseases.This article reviews the types,characteristics,mechanisms,and roles of Treg in immune tolerance,aiming to offer some important theoretical evidence for the treatment of allograft rejection and autoimmune diseases.

Cataract surgery is now often referred to as refractive surgery.It has come into the focus in recent years to choose the intraocular lens of appropriate power so as to achieve the expected postoperative refraction.Two main factors influence the measurement of intraocular lens power(IOL),the IOL power calculation formula and biological measurement of the ocular.The achievement of expected surgical outcome depends on the selection of the IOL power calculation formula and biological measurement instrument that suit the intraocular lens the specific patient.The article presents an overview of IOL power calculation with a focus on the above two aspects.

Retinal neovascularization is a phenomenon observed in various kinds of eye diseases and it can threaten the visual function of patients. Medical treatment to inhibit retinal neovascularization will give them effective help. This article reviewed animal models of retinal neovascularization and researching development of medicine in this field.

Objective:To evaluate the efficacy of laser subepithelial keratomileusis(LASEK) for the treatment of myopia and astigmatism with a thinner cornea.Methods:Eyes(128) from 67 patients were divided into 2 groups,preoperatively,according to the refractive degree.Group I contained 28 eyes with spherical and cylindrical refraction at-2.5 ~-6.0 DS and 0 ~ 2.0 DC,respectively.Group II contained 100 eyes with spherical and cylindrical refraction at-6.25 ~-14.0 DS and 0 ~-2.0 DC,respectively.Following-up was lasted over half a year and the results were compared.Results:The rates of eyes that achieved vision of 0.5 or better after operation in group Ⅰ and Ⅱ were respectively 76 % and 39 % at one week,89 % and 67 % at 1 month,93 % and 56 % at 6 months.The rates of eyes after operation in group Ⅰ and Ⅱ were respectively 93 % and 56 % for spherical refraction within?1.0 DS,and 96.43% and 76% for cylindrical refraction within?1.0 DC.Conclusion:LASEK was safer and more effective in treating low to moderate myopia with astigmatism than in treating high myopia with astigmatism.

Objective:Contrast sensitivity(CS) is a new technique which measures the discrimination capacity of the human eye to an object under low contrast conditions.It is more acute and more complete in reflecting visual function than the Snellen chart which is used to test the discrimination under high contrast conditions.Our purpose is to compare the effect of an aspheric intraocular lens(IOL) with those of conventional monofocal silicone and acrylic IOL and multifocal IOL on functional visual performance. Methods:To 90 eyes after phaco emulsification with IOL implantation,30 eyes of age-matched patients were selected as control,all patients were 50-80 years old,with no disorders,other than cataract,known to affect CS.Corrected visions were all over 0.8.The CS was measured 30 days after surgery.Results:After surgery the patients' CS returned to the normal level,but which was lower than that of the control's.The aspheric IOL provided statistically significant better contrast sensitivity at 6,12 and 18 cycles per degree. Conclusion:The use of a modified prolate IOL in cataract surgery has the potential to improve CS,which is designed to partially compensate the average spherical aberration of the cornea.

Objective:To establish the mouse model of retinal neovascularization. Methods:Twenty neonatal C57BL/6J mice were divided into two groups randomly.The treated group was exposed to 75% oxygen for 5 days and then to room air.All animals were sacrificed at postnatal day 17 and both eyes were enucleated.Endothelial cell nuclei extending into the internal limiting membrane were counted via HE stain and the expression of vascular endothelial growth factor(VEGF) was detected via immunohistochemical stain. Results:On average,25.70?4.90 endothelial cell nuclei were seen in the treated group and 0.85?1.02 in the control group.The difference was statistically significant(P