If you have that doctors note you can get away with tinting the front windshield.

But try to get some cop cards. They help.

The NJAC 13:20-1 provides sun-screening materials shall not be applied to tha windshield of a motor vehicle which, in conjunction with factory-installed glazing,reduce the transmittance of normally incident visible light below 70 percent.
Sun-screening materials may be applie to that portion of the windshield of a motor vehicle above tha AS-1 line which, in conjuction with factory-installed glazing, reduce the transmittance of normally incident visible light below 70 percent.

On February 1 2001 legislation went into effect authorizing vehicle window sun-screening material for people suffering from specific eye or skin conditions and /or transmittance and reflectivity for this clear or light tint.

Sun-screening for medical reasons
RELATED LINKSForm MR-15: Request for Medical Exemption
to Apply Vehicle Sun-screening [pdf]
Due to certain medical conditions, some drivers may need to have the windows of their vehicles tinted or "sun-screened" in a way that is not legal for other drivers. This page explains how to certify your need for sun-screening and get a "medical exemption card" from MVC for a specific vehicle.
First you need a copy of Form MR-15: Request for Medical Exemption to Apply Vehicle Sun-screening [pdf]. You may also request this form by phone at (856) 853-4118.
A licensed physician must answer the questions on the form and sign it
Mail completed forms to NJ Motor Vehicle Commission, West Deptford Regional Service Center, 215 Crown Point Road, Suite 100, West Deptford, NJ 08086
Within 3-6 weeks, MVC will mail you a "medical exemption card" that authorizes you to have specially sun-screened windows. The card is only valid for one driver and one vehicle, both of which are specified on the card
Sun-screening businesses are required to check your "medical exemption card" before applying sun-screening that is not permitted under ordinary circumstances. All window tints must meet New Jersey guidelines to pass inspection. For your convenience, MVC maintains the following list of licensed tinting facilities:

looks good! keep it, but watch for the cops