By Dr. Doug Benoit
Patient JM, a 47 yo soft lens wearer, presented for a second opinion regarding her contact lenses and vision. Current soft lenses seemed blurry compared to her glasses, and her near vision seemed strained with the monovision system she presently used (OD distance, OS near spherical SCLs). Previous doctor said this was the best she could get.
BCVA was 20/20, OD, OS, OU at distance and near with the following RX:
OD -1.75-0.75 X 180
OS -1.00-0.75 X 180
Add +1.25 OU. OS was dominant eye
Ks: OD 42.87/43.50@90; OS 43.25/43.87@85
Anterior segment exam normal. Fissure 10.5 mm.
Lower lid tangent to limbus, upper lid covers limbus by 2 mm.
Pupils 4mm in average room light
Trial lenses: Essential (aspheric)
OD 7.80 BC, -2.00, 9.5 LD, Series 2 Add
OS 7.70 BC, -2.00, 9.5 LD, Series 2 Add
Both lenses were comfortable after 10 minutes settling time.
Vision was 20/20 OD with -0.25 over-refraction; 20/20 OS with +0.50. Near vision was 20/20. Both lenses had a slightly superior ride with lid attachment, OD lens slightly higher than OS lens.
Movement was good in all positions of gaze, and translated up slightly on down gaze. Fluorescein pattern showed alignment OD centrally and slight apical clearance OS centrally, with good peripheral clearance OU.
The resultant lens powers were ordered and dispensed to JM about one week later. Her acuity and comfort were great and she has continued to do very well.
This patient really should have had a GP lens (or at least a toric SCL) from the start due to her astigmatism. Also, since her left eye was dominant, the distance eye in a monovision set up should have been her left. This was a great patient for an aspheric GP multifocal.
Patient KB, a 55 yo former GP lens wearer presented for a routine eye examination. She had recently moved to the area and wondered about getting back into contact lenses. She had stopped due to poor vision with her previous lenses.
BCVA was 20/20 OD with -4.00-1.25 X 97
20/20 OS with -5.00-0.50 X 85
Add +2.25 gave 20/20 OU at near
OD was dominant
Ks: OD 41.87/42.75@ 95; OS 41.50/42.12@85
Anterior segment exam showed mild meibomian gland plugging, but was otherwise normal. Fissure 11mm. Upper lid 1.5mm below limbus, lower lid tangent to limbus. Pupils 4mm in average light.
First lenses tried were Essential GP – 8.10 BC, -3.00 9.5 LD, Series 2 Add OU. Comfort was good OU. Acuity was 20/20 -2 OD with OR -1.50 and 20/20 OS with OR -2.25 at distance and 20/20 at near with +1.50 over the distance OR/trial lens combo.
Both lenses had slight superior positioning with lid attachment. Movement was good in all positions of gaze. Fluorescein showed slight apical clearance OU with good peripheral clearance.
The resultant lenses were ordered and dispensed, and while generally doing well, KB felt the vision OD was not adequate. Numerous parameter changes OD failed to correct the problem.
Next, a Solutions Bifocal (segmented design) was tried. Following the fitting nomogram from the lab, trial lenses were used with the following parameters:
OD 8.03 BC, -3.00, 9.5 LD, +2.00 Add 0.5 mm below geometric center, med prism @ 90.
OS 8.13 BC, -3.00, 9.5 LD, +2.00 Add 0.5 mm bgc, med prism @ 90.
Vision was 20/20 OD with -1.75 OR, 20/20 OS with -2.25 OR. Near vision was 20/20 with the distance OR in place.
The OD lens had a central position and good movement, with good translation up on down gaze. The OS lens was a bit high and the segment rode into the pupil on primary gaze. Both lenses rotated nasally about 40 degrees. Fluorescein showed alignment OD, slightly flat fit OS, with good peripheral clearance.
The resultant lenses were ordered:
OD 8.03 BC, -4.75, 9.5 LD, Add +2.00 0.5mm bgc, MAX prism @ 90
OS 8.08 BC, -5.25, 9.5 LD, Add +2.00 0.5mm bgc, MAX prism @ 90
These lenses gave 20/20 OD, OS, OU at distance and near. Both positioned centrally with the segment at the lower pupil edge in primary gaze, and translated up well on down gaze. Each lens rotated approximately 5 degrees nasal. Fluorescein showed alignment OU with good peripheral clearance.
This patient is very happy with the vision quality these lenses provide.
It is possible that the aspheric design was not correcting the corneal cyl well enough in this patient’s right eye, while the spherical BC of the latter design did the job.