Intraocular lens power calculation in eyes with keratoconus.

PURPOSE: To assess the refractive accuracy of different formulas for intraocular lens (IOL) power calculation in eyes with keratoconus. SETTING: IRCCS Fondazione Bietti, Rome, Italy. DESIGN: Multicenter retrospective interventional study. METHODS: A consecutive series of eyes with keratoconus that had cataract surgery were evaluated. Keratometry, anterior chamber depth, and axial length were measured preoperatively with optical biometry; IOL power was calculated with the Barrett Universal II, Haigis, Hoffer Q, Holladay 1, and SRK/T formulas. Subjective refraction was assessed at 1 month. The mean prediction error (PE), median absolute error (MedAE) and percentage of eyes with a PE within ±0.50 diopters (D), ±0.75 D, and ±1.00 D were calculated. RESULTS: The final spherical equivalent was -0.52 D ±1.61 (SD). In the whole sample (41 eyes), the mean PE was positive (hyperopic surprise) with all formulas; the lowest PE (0.91 D) and MedAE (0.62 D) were obtained with the SRK/T formula. In stage I eyes (n = 21), the MedAE ranged between 0.43 and 0.91 D; the SRK/T formula achieved the lowest MedAE and the highest rate of eyes with a PE within ±0.50 (61.9%). In stage II eyes (n = 13), the MedAE ranged between 0.75 D and 1.50 D; the SRK/T formula achieved the lowest MedAE and the highest rate of eyes with a PE within ±0.50 (30.8%). In stage III eyes (n = 7), the MedAE was higher than 2.50 D with all formulas. CONCLUSIONS: In keratoconus eyes, all formulas led to a hyperopic refractive outcome. The SRK/T was the most accurate formula. The results were worse in advanced stages of the disease.

The Relationship between Macular Pigment and Vessel Density in Patients with Type 1 Diabetes Mellitus.

AIM: Macular pigment density and microvascular density on optical coherence tomography angiography (OCTA) were measured in a cohort of type 1 diabetes mellitus (T1DM) patients with retinopathy in the attempt to shed light on the pathophysiology of this condition. METHODS: Eighty-two consecutive eyes of 59 patients with diabetic retinopathy examined at the Eye Clinic of the University of Naples Federico II from November 2016 to April 2017 were enrolled in this prospective study. Eighty normal eyes of 40 age-matched subjects without diabetes mellitus, without a history of glaucoma or evidence of intraocular surgery, and without retinal pathologic features constituted the control group. All patients and controls underwent a complete ophthalmic examination, best corrected visual acuity evaluation according to the ETDRS visual logMAR scale, measurement of intraocular pressure, OCTA, and evaluation of macular pigment. RESULTS: There were no significant age differences between patients and controls. Both macular pigment measurements and vessel density measured by OCTA were significantly lower in patients than in controls. A moderate correlation was found between vessel density in all ETDRS sectors and macular pigment parameters. CONCLUSIONS: There was a reduction in macular pigment and in OCTA vessel density in T1DM patients with retinopathy, which may have prognostic value in determining disease progression.

Influence of macular choroidal thickness on visual function in highly myopic eyes.

PURPOSE: To explore the retinal and choroidal thicknesses (RT, CT), as measured using enhanced depth imaging (EDI) optical coherence tomography (OCT, Spectralis) in highly myopic eyes and its relationship with visual function. MATERIALS AND METHODS: Prospective, case-control, noninterventional clinical study. CT was measured by EDI-OCT in highly myopic eyes (≥6 dpt) without any macular diseases and age-matched control eyes. A complete ophthalmological examination, visual acuity assessment and MP1 microperimetry were obtained. RESULTS: 38 myopic (15 M/23 F, mean age 51 ± 8.9 years) and 21 control eyes (5 M/16 F, mean age 50 ± 5.4 years) were included. The myopic mean refractive error was -13.3 ± 4.9 dpt and axial length 29.2 ± 2.2 mm. The mean best-corrected visual acuity (BCVA) was lower in highly myopic than in control eyes (77.3 ± 9.25 vs. 84.8 ± 0.6 letters, p = 0.0001, respectively) as was the mean retinal sensitivity (MRS; 16.32 ± 2.6 vs. 19.9 ± 0.2 dB, p < 0.0001). While RT was similar between groups (291.5 ± 24.2 vs. 283.6 ± 13.9 µm, p = 0.06, respectively), subfoveal CT was thinner in highly myopic compared to control eyes (114.3 ± 78.5 vs. 272.6 ± 110.2 µm, p < 0.0001). A significant relationship was found between subfoveal CT and MRS (R(2) = 0.22; p = 0.003) and BCVA (R(2) = 0.13; p = 0.027). CONCLUSIONS: Macular function is reduced in highly myopic eyes without any visible macular diseases compared to controls, and a significant proportion of the macular function variability seems to be related to a reduced CT.