Trading on Wall Street got off to a quiet start on Wednesday, with investors generally taking a pause after extremely high volatility levels over the past several weeks. Most major market indexes eased lower, giving back small portions of their recent gains.

However, even with earnings season winding down, a few noteworthy companies delivered some surprises to their shareholders. The news from Advance Auto Parts (AAP -4.93%) wasn't good, with weak results for the third quarter and an earnings guidance cut for the full year. When it came to eye-care specialist Alcon (ALC), however, shareholders generally liked what they saw. Read on to learn more about what both companies had to say on Wednesday.

Breaking down

Shares of Advance Auto Parts were down by 15% early Wednesday. Investors reacted negatively to the auto parts retailer's latest financial report, which showed unexpected weakness and suggested a tougher road ahead for the company.

The numbers weren't exciting. Advance Auto Parts' revenue growth slowed to 0.8% year over year, with sales clocking in at $2.6 billion. Comparable-store sales actually declined, falling 0.7%, and adjusted earnings of $2.84 per share fell well short of what most investors had anticipated and were down 11.5% from year-ago levels.

Management made several observations that caught investors' eyes. First, the auto parts retailer blamed some of the pressure on sales on increased purchases of its store-brand products, which sell at lower prices than the national brands it carries. In addition, the company maintained its 2022 sales guidance, projecting $11 billion to $11.2 billion in total revenue and comparable-store sales coming in flat to down 1%.

However, the company did cut its full-year earnings per share guidance range by $0.15 to $0.45. Its new projection is for adjusted earnings of $12.60 per share to $12.80 per share. It appears many shareholders were focused on that guidance cut and the quarter's sluggish results Wednesday morning.

Investors, it seems, are coming to realize that even some of the companies that have appeared resilient during this year's bear market are still vulnerable to changing economic conditions.

Seeing more clearly

Meanwhile, shares of Alcon picked up more than 8%. The specialist in ocular surgical supplies and vision care products announced solid performance figures for the third quarter, affirming the upbeat sentiments that investors have had about the state of the healthcare sector throughout most of 2022.

Alcon overcame tough macroeconomic conditions to post reasonably good Q3 results. Sales climbed by about 2% year over year to $2.12 billion, with particular strength in surgical equipment, implantable products, and consumables. Top-line growth would have been much higher had it not been for the strong U.S. dollar, which cost Alcon about 7 percentage points of year-over-year revenue gains. Indeed, foreign currency headwinds were strong enough to turn what would have been modest single-digit percentage sales gains for Alcon's contact lens and ocular health products into small declines from year-ago levels.

The hit on Alcon's bottom line from currency exchange impacts was even stronger. Its core earnings of $0.50 per share were down 7% in U.S. dollar terms, but would have been up 14% if measured on a constant-currency basis.

Investors weren't disturbed by management's modest reductions in full-year guidance, which included a $100 million cut in sales projections to a new range of $8.5 billion to $8.7 billion. That was largely because the company also said its constant-currency metrics would likely come in at the top end of its previous guidance ranges. With signs that the dollar's unusual strength is waning and Alcon's pending acquisition of Aerie Pharmaceuticals, shareholders hope that this healthcare company's fundamental strengths will shine through in the fourth quarter and beyond.