Surgical approaches to correct corneal astigmatism at time of cataract surgery: a mini-review

Among refractive errors,astigmatism is the most common optical aberration,where refraction changes in different meridians of the eye.It causes blurred vision at any distance and includes corneal,lenticular,and retinal astigmatism.Cataract surgery used to cause a progressive increase in the pre-exisiting corneal astigmatism because of creating a surgically induced astigmatism,for example,a large size surgery incision.The development of surgical techniques during last decades has made cataract surgery interchange to treat preoperative corneal astigmatism at time of surgery.Nowadays,three surgical approaches can be used.By placing a sutureless clear corneal incision on the steep meridian of the cornea,a preoperative corneal astigmatism less than 1.0 D can be corrected.Single or paired peripheral corneal relaxing incisions(PCRIs)provide 1.0-3.0 D corneal astigmatism correction.PCRIs are typically used for treating 1.0-1.5 D of regular corneal astigmatism,if more than 2.0 D,the risk of overcorrection and irregular astigmatism is increased.When toric intraocular lenses(IOLs)are unavailable in markets,PCRIs are still a reasonable option for patients with up to 3.0 D of pre-existing corneal astigmatism.Toric IOLs implantation can correct 1.0-4.5 D of corneal astigmatism.Several IOLs are approved to correct a high degree of corneal astigmatism with cylinder power up to 12.0 D.These approaches can be used alone or in combination.

Bandwidth expansion and pulse shape optimized for 10 PW laser design via spectral shaping

We demonstrated a scheme of bandwidth expansion and pulse shape optimized to afford 10 PW laser design via spec-tral shaping,which uses the existing Nd:glass amplifier chain of the SG PW laser.Compared to the amplified pulse with a gain-narrowing effect,the required parameters of injected pulse energy,spectral bandwidth,and shape are analyzed,to-gether with their influence on the system B-integral,energy output capability,and temporal intensity contrast.A bandwidth expansion to 7 nm by using LiNbO_(3) birefringent spectral shaping resulted in an output energy of 2 kJ in a proof-of-principle experiment.The results are consistent with the theoretical prediction which suggests that the amplifier chain of SG PW laser is capable of achieving 6 kJ at the bandwidth of 7 nm and the B-integral<π.This will support a 10 PW laser with a compressed pulse energy of 4.8 kJ(efficiency=80%)at 480 fs.

A case of circumscribed choroidal hemangioma in Sturge-Weber syndrome in China

We present a case of circumscribed choroidal hemangioma (CCH) in Sturge-Weber syndrome in a 30-year-old woman with congenital port-wine stains on the left side of face involving the upper eyelid, cheek and the nose, and she had undergone facial hemangioma surgery 3 years ago suggestive of Sturge-Weber syndrome. She presented with a 1-month history of rapidly decreased visual acuity (VA) to counting fingers in the left eye which had no prior history of visual problem. And there was no evidence of glaucoma. At 3 months after the treatment of the standard photodynannic therapy (PDT) the VA was 20/200. For some reasons, we have no idea about the changes of tumor thickness and subretinal fluid. We confirmed the curative effect of PDT treatment for CCH because of the significantly improved VA in the bad eye.

Analysis of Coronary Angiography Video Interpolation Methods to Reduce X-ray Exposure Frequency Based on Deep Learning

Cardiac coronary angiography is a major technique that assists physicians during interventional heart surgery.Under X-ray irradiation,the physician injects a contrast agent through a catheter and determines the coronary arteries’state in real time.However,to obtain a more accurate state of the coronary arteries,physicians need to increase the fre-quency and intensity of X-ray exposure,which will inevitably increase the potential for harm to both the patient and the surgeon.In the work reported here,we use advanced deep learning algorithms to fi nd a method of frame interpola-tion for coronary angiography videos that reduces the frequency of X-ray exposure by reducing the frame rate of the coronary angiography video,thereby reducing X-ray-induced damage to physicians.We established a new coronary angiography image group dataset containing 95,039 groups of images extracted from 31 videos.Each group includes three consecutive images,which are used to train the video interpolation network model.We apply six popular frame interpolation methods to this dataset to confi rm that the video frame interpolation technology can reduce the video frame rate and reduce exposure of physicians to X-rays.