A Novel Dual-wavelength, Dual-function Laser System for Presbyopia and Glaucoma Treatments

To update the accommodation mechanisms and propose a dual-wavelength, dual-function laser system for presbyopia and glaucoma treatments.Study Design: Laser sclera softening (LSS) for increased accommodation of presbyopic eyes.Place and Duration of Study: New Taipei City, Taiwan, between Jan., 2023 and Feb., 2023.Methodology: Accommodation gain (AG) can be improved by: (i) thermal shrinkage of the scleral stroma and ciliary body, or (ii) softening of the scleral stroma (with temperature range of 700C to 900C), such that the the lens front and back curvature change (or lens thickening), leading to the thickening of ciliary body and its apex, and the increase of the space of ciliary body and lens equation (SCL), and the length of the posterior vitreal zonules (PVZ) increases.Results: A novel dual-color laser system having wavelength A and B, acting on the front-zone and back-zone of the sclera, respectively, where laser-A has a deep thermal penetration the sclera and ciliary body (CB) (0.5 to 1.0 mm); and laser-B has a shallow penetration depth in the sclera (0.3 to 0.5 mm), based on the optical property of the sclera. Laser-A (having a wavelength about0.8 to 0.98 um) leads to thermal shrinkage of the ciliary body such that the CLS is increased for accommodation gain which is much more effective than the prior art.Conclusion: The increase of AG can be achieved by scleral softening and ciliary body shrinkage which increase the SCL. A proposed novel dual-color laser system acting on the front-zone and back-zone of the sclera, respectively, could provide higher AG than that of single wavelength, or prior arts using scleral ablation. However, further clinical studies are required to justified the proposed novel system with predicted advantages and efficacy based on the optical properties of sclera.

Research progress on the relationship between ciliary muscle and myopia / 国际眼科杂志(Guoji Yanke Zazhi)

As a key ocular structure, ciliary muscle has a major role in accommodating both eye and aqueous humor drainage. Recent studies have found that the position and shape of ciliary muscles in myopia are significantly different from those in emmetropia or hyperopia, and the differences of ciliary muscle may affect the progress of myopia by altering ocular accommodation, choroidal tension and intraocular pressure. The present evidence indicating that the thickening of posterior ciliary muscle was associated with the development of myopia, but the mechanism has not been clearly confirmed. This paper summarizes the relationship between the differences of ciliary muscle and myopia, and the possible mechanism of myopia changes affected by ciliary muscle, so as to provide reference for follow-up research.

Multisectorial changes in the ciliary muscle during accommodation measured with high-resolution optical coherence tomography / Alterações multissetoriais no músculo ciliar durante a acomodação com uma tomografía de coerência óptica de alta resolução

ABSTRACT Purpose: To measure changes in the anterior ciliary muscle during accommodation at the nasal, superior, temporal, and inferior sectors by means of an anterior chamber optical coherence tomographer, and correlate them with vergence changes. Methods: Twenty-four subjects with healthy, phakic eyes, whose mean age was 27.1 ± 8.9 years, underwent measurement with an anterior chamber optical coherence tomographer. The anterior ciliary muscle was measured at the nasal, temporal, superior, and inferior sectors for 0, -1, -2, and -3 D of vergence. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. Results: The anterior ciliary muscle area significantly increased with accommodation for each sector, with a maximum increase of about 30% for the nasal-temporal sectors and about 25% for the inferior-temporal sectors. The linear model showed a tendency toward a positive relationship between change in the ciliary muscle area of each sector and vergence. Conclusion: The anterior ciliary muscle area tends to increase with accommodation, although the increase has been shown to be symmetric between the pair sectors superior-nasal and inferior-temporal. These results may help to increase understanding of accommodation biometry and biomechanics.

RESUMO Objetivo: Medir as alterações do músculo ciliar anterior durante a acomodação nos setores nasal, superior, temporal e inferior, através de um tomógrafo de coerência óptica de câmara anterior, e correlacioná-las com alterações de vergência. Métodos: Vinte e quatro indivíduos com olhos saudáveis e fácicos, com idade média de 27,1 ± 8,9 anos, foram submetidos à medida com um tomógrafo de coerência óptica de câmara anterior. O músculo ciliar anterior foi medido nos setores nasal, temporal, superior e inferior para 0, -1, -2 e -3D de vergência. Um modelo linear foi utilizado para avaliar a correlação de cada parâmetro do olho com a demanda acomodativa. Resultados: A área do músculo ciliar anterior aumentou significativamente com a acomodação em cada setor, com um aumento máximo foi de cerca de 30% para os setores naso-temporais, e cerca de 25% para os inferiores-temporais. O modelo linear mostrou uma tendência para uma relação positiva entre a alteração da área do músculo ciliar de cada setor e a vergência. Conclusão: A área do músculo ciliar anterior tende a aumentar com a acomodação, embora o aumento tenha se mostrado simétrico entre os setores superior-nasal e inferior-temporal. Estes resultados podem ajudar a aumentar a compreensão da biometria e biomecânica da acomodação.

Interpreting human eye accommodation from the perspective of morphological studies: A discussion with the author of ‘A novel concept of accommodation: Human eyes optical system based on hyperfocal distance-micro zoom ' / 中华实验眼科杂志

Accommodation of the human eye ian extremely complex and dynamiprocess,which iaccomplished by the interaction between the central nervousystem and variouoculastructurethaare relevanto accommodation.Varioumechanismof accommodation have been puforward since the beginning of the 19th century,among which Helmhohz'theory ithe mosfamous.However,iistill challenged by othetheories.So far,the mechanism of accommodation hanobeen fully understood.The mosdirecmethod to study accommodation ito observe changein the biometry of the oculastructureduring accommodation,which ialso the mosobjective interpretation of accommodative mechanisms.The rapid developmenof imaging technologiein regardto ophthalmology makethipossible.Thiarticle aimto describe the use of variouimaging technologiein oculaaccommodative studiein vivo from the perspective of morphology.

A novel concept of accommodation:Human eyes optical system based on hyperfocal distance-micro zoom / 中华实验眼科杂志

Based on a concept of the hyperfocal distance from photographic lens,this study proposes that emmetropia presents far-hyperfocal distance,near-hyperfocal distance and accommodative hyperfocal distance.When emmetropic presbyopias completely lose the ability of accommodation,its farthest blur point is not beyond 1.5 m,even not being at infinity,and the phenomenon of dark focus both completely match with the definition of hyperfocal distance.On the other hand,after cycloplegic mydriatics in emmetropia,it could be found in the region of depth-of-field that there is no change in the back depth of field (clearness in far vision),but change was found in the front depth of field (blur in near vision).It conforms well to the definition of the hyperfocal distance,demonstrating that human eyes belong to the hyperfocal distance optical system.Furthermore,it is reported that the emmetropic presbyopias rarely matched the spectacles higher than +2.50 D in their whole life;therefore,it can be inferred that their accommodative amplitude in youth is equal to this corrected value.This value accounts for about 4％ of the total refractive power in human eyes,so it is suggested that human eye is a micro zoom optical system.Based on the objective existence of hyperfocal distance,the author proposes that human eye is an integrated accommodative mechanism.It includes three components:the accommodative mechanism of near vision,the measuring and controlling mechanism of near vision,and the general control of near vision.This paper discusses the accommodative mechanism of near vision and the resting mechanism of distance vision based on the hyperfocal distance,and considers that when human eye transfer into the accommodation of near vision from the normal distance vision of hyperfocal distance.There are three different pushing forces contributing to lens deformation and its anterior shift,and these forces cause four different accommodative efforts,which constitute the real accommodative efforts in the relative tissue.This paper also points out that it is only the mode of pushing accommodation that can make the lens vary refraction quickly and greatly,and control the amount of deformation effectively.That can not be achieved by the stretching mode proposed by Tscherning & Schachar,because some authors have verified that excessive pulling would result in decline in the refraction,which would be difficult to regulate and control the eye.Similarly,the self-bulging mode of Helmholtz & Gullstrand will not work neither,because it is unable to control the amount of lens deformation that is its fatal defect.

A brief talk on ‘ A novel concept of accommodation : Human eyes optical system based on hyperfocal distance-micro zoom ' / 中华实验眼科杂志

Accommodation is a phenomenon that crystalline lens change its refractive power when human eyes see the near objects clearly.The article of A brief talk on ‘ A novel concept of accommodation:Human eyes optical system based on hyperfocal distance-micro zoom'.written by Luo Fu-ming introduces a concept of hyperfocal distance from the camera.Based on the characteristic of hyperfocal distance,the author proposes that there are actually three kinds of hyperfocal distances in human eyes:far-hyperfocal distance,near-hyperfocal distance and accommodative hyperfocal distance.It is important to understand this article that whether the ciliary muscles contract to push the zonules in accommodation,and then the zonules are forced to push the lens equator,or the ciliary muscles contract to relax the tensional zonules,then the posterior surface of the lens moves forward.In view of the anatomic structure,the possibility that the ciliary muscles contract to push the zonule and then the slim zonules push the lens equator is less than that the ciliary muscles contract to relax the tensional zonules and then the posterior surface of the lens moves forward in accommodation.In my opinion,the contraction of the ciliary muscles would startup actively in accommodation.So when the eyes transfer from near vision to distance vision,the ciliary muscles (contracting circular muscles) will return to the relaxed normal state immediately.The crystalline lens will immediately recover to its original relatively flatten state by traction of the zonules,rather than passive compression.Because the crystalline lens is not the startup body but a supporting body in accommodation.The accommodation of human eye is very complicated.During the whole process of accommodation,there are not only contraction of ciliary muscles and increase of refractive power in crystalline lens,but also accompanied reaction of miosis and convergence.So it is difficult to explain the complex activity of human eyes using any extreme,mechanical and single mode.

Effect of Prostaglandin F2alpha on the Production of Nitric Oxide in Cultured Ciliary Muscle Cells

PURPOSE: To investigate whether prostaglandin F2alpha (PGF2alpha) affects on the production of nitric oxide (NO) in cultured ciliary muscle (CM) cells. METHODS: Following primary culture of CM cells from porcine eyes, the cells were exposed to PGF2alpha (PhXA85, latanoprost free acid) with and without pretreatments of NO synthase inhibitor (L-NAME, N omega- Nitro-L-arginine methyl ester) and cyclooxygenase inhibitors (indomethacin and dexamethasone) for 3 days. The cellular survivals were also evaluated in serum-deprived and hypoxic conditions induced by sodium cyanide. The cellular survival and nitrite production were assessed by MTT and Griess assay, respectively. RESULTS: PGF2alpha enhanced the production of NO significantly in cultured CM cells in a dose-dependent manner, while various inhibitors abolished this effect. PGF2alpha was not cytoprotective in serum-deprived and hypoxic conditions. CONCLUSIONS: The current results suggest that PGF2alpha potentiates NO production but is not cytoprotective in CM cells. This PGF2alpha-induced NO production in CM cells may be involved in the regulation of uveoscleral outflow.

Effect of Cholinergics on the Survival and Production of Nitric Oxide in Cultured Ciliary Muscle Cells

PURPOSE: To investigate the effect of cholinergics on the survival and production of nitric oxide (NO) in the cultured ciliary muscle cells. METHODS: Primarily cultured porcine ciliary muscle cells were exposed to the pilocarpine and to the atropine at various concentrations for 24 hours. The cellular survival was assessed by rapid colormetric assay (MTT assay) and the production of nitrite was measured by Griess reaction. NO production was measured after co-administration of pilocarpine and atropine. RESULTS: Cultured ciliary muscle cells expressed alpha-smooth muscle actin. Both pilocarpine and atropine did not affect the cellular survival (p>0.05). Pilocarpine decreased the production of NO significantly from 10 micro M (p<0.05). Atropine increased NO production from 1 micro M and inhibited pilocarpine-induced inhibition of NO production. CONCLUSIONS: Pilocarpine decreases the production of NO that abolished by atropine in the ciliary muscle cells. Pilocarpine may constrict the ciliary muscle by inhibiting production of NO and decrease uveoscleral outflow subsequently.

The Effect of Lens on the Contractability of Ciliary Muscle

There are many factors affecting the outflow facility. Structural changes of aqueous outflow channel by ciliary muscle contraction play major role in the control of outflow facility. Although many studies on the physiology of outflow facility have been done by many authors, the lens effect on the ciliary muscle contractability has not been reported. We performed clear corneal phacoemulsification and foldable intraocular lens implantation in 42 cataract patients and measured intraocular pressure(IOP) pre and postoperatively by Goldmann applanation tonometer and determined outflow facility with and without 2% pilocarpine before and after cataract surgery, respectively. We analysed IOP changes after surgery, and assessed ciliary muscle contractability by analysing outflow facility changes. Statistical analysis was done by Wilcoxon`s signed rank test. IOP decreased by 2.4+/-0.4mmHg(mean+/-SEM)(P<0.001): outflow facility with and without pilocarpine increased by 0.080+/-0.012microliter/min/mmHg(P<0.001) and 0.045+/-0.006microliter/min/mmHg(P<0.01), respectively after lens extraction: outflow facility increased 2.8+/-0.4 times by pilocarpine itself after lens extraction(P<0.001). The lens connected to the ciliary muscle muscle by zonnule may have an influence on ciliary muscle contractability.