The first part of the operation required to make space for the new nervous tissue without harming the patient. Lith had no experience in the field and the brain was too sensitive an organ for a rookie.
Vastor took the lead, removing what he could and using Body Sculpting to slightly alter Zinya's skull to create more room whenever he had no other choice. The changes were so subtle that only a detailed diagnostic spell like Scanner could detect them.
When he was done, he stepped out and made space for Lith.
"Remember, the best approach is always to go from easy to hard. Start by creating the optic nerve from the eye end and leave the connection with the thalamus for last. That way, we can immediately check if the brain receives the right stimuli.
"If we worked the other way around and make even just a few mistakes, the sudden massive flow of wrong inputs might cause permanent damage. Plus, we would need to destroy all the connections and redo everything from scratch, since we would have no idea what went wrong." Vastor said.
Lith did as instructed and created the optic nerve, the chiasma, and the optic trait. Then, he used his Probe spell to create small tendrils of semi solid mana that stimulated Zinya's visual cortex following Kamila's optic nerve pattern.
The tendrils would carry the electrical impulses that light generated by hitting Zinya's eyes and allow Lith to check how the brain processed the acquired information. That way Lith could make sure that the impulses would travel through the right pathway before making a physical connection.
"Zinya, I need you to keep talking during the entire procedure. I don't care what you say, I just need to check your cognitive functions and your mood. If you feel anything weird, just tell me. Don't hold anything." Lith said.
Zinya nodded and started to recount whatever she remembered from her youth. As long as everything was okay after testing with Probe, Lith would grow the optic nerve, yet more than once he was forced to stop and backtrack.
Sometimes the electrical impulses would cause her small spasms. Other times fits of pain or uncontrollable mood changes. Every time that happened, Lith had to quickly disconnect the tendrils and search for another point of access to her brain.
Luckily, the more the procedure progressed on the right track, the more Zinya regained her sight. It gave Lith a clear indicator of his progress and gave Zinya something useful to talk about.
At the beginning she could only see a white light, but every time Lith found a proper pathway she would start to see small dots of colors appear.
"Dammit, Lith. Your Probe spell is amazing. It saved us a lot of mana and the patient a lot of pain." Vastor said. Even with his expertise, he would have missed the right connection more than once.
Yet his help proved to be invaluable for Lith. Whenever he had no idea how to proceed, it would take the Professor just a couple of tries to find the right pathway among hundreds of seemingly identical alternatives.
"You are doing great, son. I'm really proud of you."
Lith nodded, not having the luxury of wasting his focus to reply. What Vastor had no idea of, was that to be able to carry a physical stimulus, Probe required a great expenditure of mana.
It was one of the reasons Lith couldn't hold it for long back when he had used Probe for the first time on Zinya. Such a huge amount of energy would have burned her brain and left him weakened in a matter of minutes.
Now, however, he was only creating the extremities of the optical nerve with Probe, lessening the burden on both Zinya and himself. The procedure took a few hours, forcing Lith to take some rest.
Vastor or Quylla stepped in to check on the progress, keeping the patient's conditions stable while Lith consumed a tonic and used Invigoration to regain his mental focus.
Mana wasn't an issue, but he could feel his concentration declining. For a normal Healer, it would have taken several minutes for a tonic to give them back their focus, but Invigoration had no such problem.
By the time everything was over, Zinya could see better than most.
"Is it over?" She asked when she felt the straps being removed.
"Yes. Can you touch my hand?" Lith offered her his right hand, keeping it low and on the right. Zinya had no problem with depth nor distance perception. She managed to grab Lith's hand easily no matter where he placed it within her field of view.
"Thank you so much. I know it isn't worth much coming from a blind person, but you all are the most gorgeous people I have ever met." Zinya embraced and kissed the entire medical staff and the nurses that had taken care of her until that day.
Kamila and Zinya hugged in joy while Lith and Vastor planned together her physiotherapy. Zinya still needed to learn how to move normally, read, write, and even to associate a name to common objects.
"One more thing." Vastor cleared his throat to get everyone's attention.
"We can keep Zinya here for a couple more days to make sure that there are no post-op complications, but then she has to leave. We need the room for the next patient."
"How much do I owe you?" Kamila asked.
"I'm sorry your sister isn't part of your family register, otherwise the army would cover part of the expenses." Vastor handed her the invoice.
Kamila owed the White Griffon much less than she had feared. Two gold coins for Vastor's consultation and Body Sculpting, 30 silver coins for Quylla's research job, and 70 silver coins for Zinya's stay at the White Griffon, for a total of three gold coins.
It was still a huge amount of money considering that Kamila was paid two silvers per week. Body Sculpting was the most difficult technique, after all. Most people would more easily afford a magical item to compensate for their handicap rather than having it treated.
"That's it? I expected at least ten gold coins." It was how much the cheapest and less competent Healer would have asked, the same price of two communication amulets.
Kamila wouldn't have been able to afford her own if the army hadn't gifted it to her when she had been promoted to First Lieutenant.
"You would be right if the lead Healer had charged you with something, but he didn't." Vastor pointed at Lith. He knew how Kamila hated to feel indebted, so he didn't ask for favors to Vastor nor the academy.
Otherwise the whole procedure would have been free of charge.
'I respect Kamila's desire to save her sister and I can't take it away from her. If I stepped in and solved everything by myself, she would feel useless. All of her struggles and fears would be for nothing.
'This way, she can still feel like she has done her part because she did. Even without me, Zinya would still have got her sight, it would have just been more expensive.' Lith thought.
"How much do I owe you?" Kamila turned to Lith repeating her question.
"I'll cut the workmanship and charge you only at cost price. So, it's 50 silver coins for the amulet and dinner for the procedure."
