I’m not a formal historian. What I am, is a physician. This is not superbly well parsed, as I am using my phone on a very slow shift here at the hospital.

TL;DR: We are currently incapable of performing that type of surgery today. Arthur Schopenhauer was writing what he hoped, as he was a transcendental philosopher, and definitely not a doctor or surgeon.

With regards to surgically treatable options to cure blindness:
The most common sight-restoration surgery is actually cataract removal... but that does not affect early childhood/ blindness from birth. For a quick overview, primitive cataract surgery was literally a needle that was inserted and used to push the cataract out of the way (couching). Extracapsular cataract extraction was documented to 600CE by Sashruta in India. In that a sharp needle would puncture the eye, a small incision was made in the capsule and the patient would valsalva maneuver with a closed nostril until the lens started to pop out of the eyeball and vision improved. “Modern” ECCE began in 1747, by Jacque Daviel in France with a 10mm incision cataract surgery began with in France. Actually, the type of spoon he developed is essentially still used today for cataract removal. Intracapsular cataract extraction was developed in 1753 by Samuel Sharp in London. The placement of Intraocular lenses was developed in 1949 by Sir Harold Ridley in London. Foldable Intraocular Lenses were developed in 1979 by Kai-yi Zhou. “Modern” cataract surgery in 1993 combining the foldable lens, topical anesthetic and antibiotics and using Phacoemulsification (ultrasound to emulsify the cataract). Laser technique was approved in 2010. (*)

With regards to general surgical practices and the rapid development of surgery in the 1700s: Surgery in the 1750s-1820s was making huge advances overall. In 1718, French surgeon Jean Louis Petit (1674-1750) developed a tourniquet to stop bleeding during an amputation. Petit's tourniquet worked by twisting a screw compressor device that clamped down on the patient's leg and on the lower abdomen. It could stop the blood flow in the main artery and provide for higher leg amputations. Petit's tourniquet is considered by many sources to be one of the "most important surgical advancements before the advent of anesthesia." (1). Multiple theories and best practices to clean wounds (and surgical incisions) draining over closing wounds with sutures were developed and led to increased -survival- from surgery and amputations within the 1700s. (2)

Antiseptics were started to be developed circa 1752, the term coined by John Pringle in 1752. So interested were French surgeons in antiseptics that the Academy of Sciences and Arts and Fine Letters of Dijon offered a prize for the best essay on the use of antiseptics. The winner discussed applications of turpentine, alcohol, benzoin, and aloe. (3)

In 1756 British and French surgeons were performing glossectomies, the ligation and removal of the tongue to treat tongue cancer. Cauterization however was still performed by the use of hot iron. (2)

By the 1790s, surgeons were treating cancer of the colon by removing sections of the bowel and redirecting the anus to the abdomen (colostomy). The first recognized successful colostomy was performed in 1793 when French surgeon C. Duret attended a three-day-old infant with a perforated anus. Duret performed a colostomy and the patient lived to be 45 years old. (2)

A German surgeon, Lorenz Heister performed the first known successful thyroidectomy in 1752. Appendectomies were performed first in London in 1736 and then in Paris 20 years later. (2)

Great advances in medical literature in this era include: Percival Pott, Injuries of the Head from External Violence. Pott also wrote on fractures, ruptures, and palsy. William Cheselden, The Anatomy of the Human Body (1713), and The Anatomy of Bones (1733). John Hunter, The Natural History of Human Teeth (1771), A Treatise on Venereal Disease (1786), and A Treatise on the Blood, Inflammation and Gunshot Wounds (1794). (3)

In 1785, John Hunter and Pierre Joseph Desault both developed a surgical ligation of the femoral artery to repair an aneurism. (5)

The 18th century in general had a massive increase in the functionality, cleanliness and development of hospitals, separate surgical rooms, new anatomical techniques. The overall mortality rate remained very high, primarily from post surgical infections. The earliest general anesthetic was developed in Japan in the early 1800s. Patients were rendered unconscious for anywhere from 6-24 hours. By the mid 1800s, ether and chloroform were being used as anesthetic. (5)

It wasn't until the 1900s that the likelihood of surviving surgery was greater than the likelihood of dying during or as a result of surgery. (6)

In terms of childhood blindness: Genetic blindness (multiple syndromes) and other forms of childhood blindness, including birth anoxia (not enough oxygen during the birth process), structural damage or defect of the eye, lens, or retina remains incurable today. There are major research programs worldwide involved in trying to furnish sight to those who cannot see. We might actually be able to fulfill Schopenhauer’s vision for many within the next few years... only 200 years late, but hey. Science and Philosophy work differently.

Current research: Recent developments include the use of CRISPR to treat genetic retinal impairment. https://geneticliteracyproject.org/2021/01/27/inherited-blindness-can-now-be-cured-thanks-to-crispr/

A mixture of gene therapy and specialized bionic glasses. https://www.fightingblindness.org/research/bionic-sight-s-optogenetic-therapy-enables-blind-patients-to-detect-light-and-motion-in-early-trial-217

Gene therapy for Leber congenital amaurosis, https://www.newsobserver.com/news/business/article244552802.html

Reprogramming the eye to “be young again.” https://www.studyfinds.org/blindness-cure-vision-loss-fully-restored-glaucoma/

1 Davis, Geetha. “The Evolution of Cataract Surgery.” Missouri medicine vol. 113,1 (2016): 58-62.

2 Cartwright, Frederick F. The Development of Modern Surgery. New York: Thomas Y. Crowell and Company, 1967.

3 Meade, Richard Hardaway. An Introduction to the History of General Surgery. Philadelphia: W.B. Saunders Company, 1968.

4 Wangenstein, O.H. and Sarah D. Wangenstein. The Rise of Surgery. Minneapolis: The University of Minnesota Press, 1978.

5 Zimmerman, Leo M. and Ilza Veith. Great Ideas in the History of Surgery. New York: Dover Publications, 1967.

6 Brock C. Risk, responsibility and surgery in the 1890s and early 1900s. Med Hist. 2013 Jul;57(3):317-37. doi:10.1017/mdh.2013.16