Norristown, Pennsylvania (CNN) Spending two days sitting in a Pennsylvania courtroom listening to lawyers argue over his blindness -- and with a criminal trial seven months away -- is likely the last place Bill Cosby imagined he would find himself at 79 years of age.

But that's where he was this week as a Montgomery County judge listened to lengthy pre-trial arguments on several key issues -- the outcome of which will significantly shape the famous comedian's upcoming trial.

Much has changed in Cosby's life since May of last year when he wrapped up his "Far From Finished" comedy tour. Not only does he now face three counts of aggravated indecent assault stemming from accusations made by a former Temple University employee, Andrea Constand, but his lawyers say he is blind, and that condition is severely hampering his defense.

Cosby has pleaded not guilty to all charges.

'Can he really not see a photo six inches from his face?'

TV cameras, reporters, and onlookers swarmed the Norristown courthouse on Tuesday and Wednesday, hoping to catch their first glimpse of Cosby since his lawyers revealed in court filings last month that he suffers from a "degenerative eye condition."

"He can't write, he can't read, he can't draw or drive -- he's blind," defense attorney, Angela Agrusa, told CNN Friday.

Constand's allegations are only part of a longer story for prosecutors, as they want to show he's engaged in a specific, repeated pattern of criminal behavior over the years by introducing testimony from at least 13 other women who claim that Cosby sexually assaulted them. And this is where his sight becomes a legal issue, because Cosby's lawyers say the Commonwealth should have charged him long ago, and it is now impossible for him to effectively refute such claims, as he cannot identify the accusers without his sight.

"[W]ithout his eyesight, Mr. Cosby cannot even determine whether he has ever even seen some of his accusers, let alone develop defenses and gather exculpatory evidence," Cosby's lawyers said in a motion to get the case dismissed. On Tuesday, his lawyers provided Judge Steven O'Neill with a report from ophthalmologist Dr. David G. Lotufo to corroborate their claims.

While the report has not been released to the public, Cosby's lawyers revealed to CNN that the report by Lotufo said Cosby has "severe" glaucoma in both eyes and is already blind in his right eye.

Cosby's lawyers told CNN that Lotufo recently conducted a "full evaluation" of Cosby before making the diagnosis.

But in court on Wednesday, prosecutors initially cast doubt on the reliability of Lotufo's report, questioning whether it could constitute reliable evidence without a baseline evaluation of Cosby's vision at the time of the alleged incident in 2005. "It looks like something you'd get from a LensCrafters at a mall," Deputy District Attorney Robert Falin argued, referring to Dr. Lotufo's report -- causing Cosby to laugh out loud.

"Can he really not see a photo six inches from his face?" Falin added, posing the question to make his point.

'This didn't happen overnight'

Those who are close to Cosby say he has suffered from a gradual decline in vision for years. While unbeknownst to audiences who attended his performances last year, Cosby required neon yellow tape be stretched from the backstage area to his chair on stage so that he could see, according to his publicist, Andrew Wyatt.

"This didn't happen overnight," Wyatt told CNN on Thursday. Wyatt is regularly seen at court hearings by Cosby's side, guiding him by the bicep in and out of the courthouse, and helping him into his car.

His loss of sight has been a "major adjustment" in his life, according to Agrusa -- though it remains unclear when exactly he was first diagnosed with glaucoma or declared legally blind.

Medical experts say that glaucoma does "progressive damage" to the optic nerve, leading to blind spots in one's vision. Often by the time a person first notices symptoms, the condition has advanced, according to Dr. Anastasios Costarides of the Emory Eye Center in Atlanta.

"Once you've lost vision from glaucoma, you can't bring it back," Costarides, who is not involved in the Cosby case, told CNN.

Some legal experts, however, say that it is unlikely Cosby's blindness will result in the dismissal of all charges. Laura Coates, CNN legal analyst and a former prosecutor, explained that even if Cosby is blind, he has "ample tools at his disposal to provide his lawyers with an alibi or other exculpatory evidence" to challenge the credibility of the 13 other accusers. A fair trial is not "contingent on eyesight," Coates said.

The judge gave no indication when he would issue a ruling on the defense motion to dismiss.

Expressions in court show mixed emotions

Vision issues aside, the famous entertainer did not shy away from showing his feelings in court this week, entering the courtroom with a confident stride and cracking a smile as his lawyers wrangled with the judge. "He's doing well, he's in great spirits," Wyatt told CNN.

Yet at other times, he appeared more withdrawn.

Cosby frowned, looking down at the floor as District Attorney Kevin Steele began describing alleged "drug-facilitated rapes" and a "decades-long pattern of sexual assault." During other long stretches of argument, Cosby leaned back in his chair away from counsel table, with his head in his hand.

Cosby's wife, Camille, was not with him in court this week, but Wyatt told CNN that Cosby has the "full support" of his family and friends, and Wyatt expects that his wife will attend trial.

"He just looks so sad to me ... I feel bad for him," a supporter, Monica Lyons, said outside the courthouse as she watched Cosby's car drive away. "He's been America's dad for so long."